Method for measuring axial (transverse), coronal (frontal), and sagittal (bisection) alignment of the lower extremities

Abstract

A method for determining axial alignment of a lower extremity includes determining a three-dimensional volume based on a scan of a patient's lower extremity; determining a level of hip torsion by referencing a first axis of symmetry of a femoral neck and a second axis of symmetry of a distal part of the femur, where the hip torsion level is defined by an angle between the first axis of symmetry and the second axis of symmetry; determining a level of tibial torsion by referencing a third axis of symmetry of a proximal part of the tibia and a fourth axis of symmetry of a distal part of the tibia, where the tibial torsion level is defined by an angle between the third axis of symmetry and the fourth axis of symmetry; and providing the level of hip torsion and the level of tibial torsion to a user.

Description

Detailed Description of the Invention

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 256,741, filed October 18, 2021, the disclosure of which is incorporated by reference in its entirety herein. [Background to disclosure]

[0002] The lower leg consists of the femur, tibia and fibula, and the foot. Alignment of the lower leg is important for proper function, joint longevity, avoidance of injury, and comfortable use of the lower leg. Malalignment of the lower leg can result in the opposite results: improper function, deterioration of the joint, vulnerability to injury, and discomfort when using the lower leg. Femoral version and tibial torsion are important factors when considering lower leg alignment.

[0003] Femoral torsion is a measure of the orientation of the femoral neck relative to the femoral condyles at knee level. In most cases, the femoral neck is oriented anteriorly in the coronal (frontal) plane compared to the posterior aspect of the femoral condyles, to which the term femoral anteversion applies. In cases of posterior orientation, the term femoral retroversion applies.

[0004] The natural history of femoral anteversion is that infants are born with a high degree of femoral anteversion, which decreases with age. Typically, femoral anteversion is 40° at birth and decreases to 16° with skeletal maturation. Population differences have been observed based on sex, with females having greater anteversion than males. Other series suggest that additional variation exists based on ethnicity.

[0005] Femoral torsion is a relevant measurement that affects hip joint range of motion and pathology. Significantly increased femoral anteversion affects the rotation profile of the lower limb, leading to increased internal rotation, and is associated with developmental dysplasia of the hip joint, as well as femoroacetabular impingement ("FAI") and hip osteoarthritis ("hip OA").

[0006] Although a high degree of correlation has been found between computed tomography ("CT") and magnetic resonance imaging ("MRI") anteversion measurements, significant deviations in absolute anteversion numbers suggest that they may not be interchangeable. The lack of a high degree of correlation for range of motion suggests that the description of the complex anatomical rotation of the hip joint that femoral anteversion represents may be incomplete or oversimplified.

[0007] Tibial torsion is a measurement of the twisting or angulation of the tibia in a patient. Tibial torsion is often seen in children and in some cases in adults. Tibial torsion can manifest as either an internal rotation resulting in a turned-in (i.e., clubfoot) or an external rotation resulting in a turned-in.

[0008] Tibial torsion is a relevant measurement affecting pathology. Significant tibial internal and / or external rotation is known to affect the rotation profile of the lower extremity, leading to pain and discomfort that may be experienced in the leg, hip, knee, and / or foot, as well as instability of the foot and vulnerability to other injuries.

[0009] In one study, CT data used to measure the relationship between the foot and the tibiotalar joint showed large variations in patients with tibial torsion who underwent ankle arthroplasty. In this study, 157 patients demonstrated a mean tibial torsion of 34.5 ± 10.3 degrees (range 11.8 to 62 degrees) (Ali-Asgar Najefi A, Malhotra K, Goldberg AJ, Mechanical and anatomical axis of the lower limb in total ankle arthroplasty. Foot (Edinb). 2020 Sep;44:101666. doi:10.1016 / j.foot.2020.101666. Epub 2020 Feb 4).

[0010] Physicians use the hip-knee-ankle angle (HKA), a measurement of lower limb alignment. In healthy subjects, there is a large variability in lower limb alignment, and there is a great interest in lower limb alignment for total knee arthroplasty (TKA) surgery to restore the natural 3D knee alignment and soft tissue balance after surgery. Several studies have validated arithmetic HKA (aHKA) algorithms to estimate the natural alignment in the prearthritic stage of the lower limb using full-length lower limb radiographs. aHKA can represent prearthritic alignment in the absence of asymmetric bone loss. However, HKA implements two-dimensional radiographs, which are often inaccurate for measuring axial (transverse) plane alignment.

[0011] Coronal (or frontal) plane ankle alignment is typically assessed using the tibiotalar angle (TTA), which relies on the anatomical axis of the tibia (AAT) and the articular surface of the talus as landmarks. The AAT often differs from the functional axis of the lower extremity (MAL), especially in proximal deformities (genu valgum or genu varum) and post-traumatic cases, so a more accurate measurement has been suggested: the functional axis of the lower extremity relative to the articular surface of the talus (MAL-TA).

[0012] In some instances, the foot attempts to compensate or adapt to problems in the leg that manifest above the foot. For example, the foot may adapt to malalignment due to tibial or hip twist (e.g., genu varum or genu valgus). Whether the compensation occurs in the foot or elsewhere in the leg, undesirable pathology may result including joint deterioration, discomfort, and limited range of motion.

[0013] Improper reduction of alignment in the coronal, sagittal, or axial planes and failure to address soft tissue imbalances in the joint replacement increases the risk of failure.

[0014] This poor understanding of axial alignment issues may also explain the poor understanding of the etiology of many musculoskeletal (MSK) pathologies. For example, patellofemoral disorders, flat feet, and lower extremity soft tissue injuries may be secondary to tibial and / or hip torsion issues, as well as the development of unilateral arthritis.

[0015] What is needed are improved systems and methods for determining the axial alignment of a patient's lower extremities, and more specifically, what is needed are intra- and inter-operator reliability to provide accurate and reliable measurements of hip and tibial torsion, either alone or in combination. [overview]

[0016] According to one example ("Example 1"), a method for determining axial alignment of a lower extremity includes determining a three-dimensional volume based on a scan of a patient's lower extremity; determining a level of hip torsion by referencing a first axis of symmetry of a femoral neck and a second axis of symmetry of a distal part of the femur, where the hip torsion level is defined by an angle between the first axis of symmetry and the second axis of symmetry; determining a level of tibial torsion by referencing a third axis of symmetry of a proximal part of the tibia and a fourth axis of symmetry of a distal part of the tibia, where the tibial torsion level is defined by an angle between the third axis of symmetry and the fourth axis of symmetry; and providing the level of hip torsion and the level of tibial torsion to a user.

[0017] According to another example ("Example 2") in addition to Example 1, the step of determining the axis of symmetry of the femoral neck, the distal portion of the femur, the proximal portion of the tibia, and the distal portion of the tibia includes determining the axis of symmetry by referencing a two-dimensional or three-dimensional shape of the lower leg in an image from the scan.

[0018] According to another example ("Example 3") in addition to Example 1, the step of determining the axis of symmetry of the femoral neck, the distal portion of the femur, the proximal portion of the tibia, and the distal portion of the tibia includes determining the axis of symmetry by referencing a reference point on the lower leg in an image from the scan.

[0019] According to any one of Examples 1 to 3 plus another Example ("Example 4"), the angles between the first axis and the second axis are compared within a single plane.

[0020] According to any one of Examples 1 to 4 as well as another example ("Example 5"), the scan is a single scan of the entire lower extremity.

[0021] According to any one of Examples 1-5 as well as another example ("Example 6"), the scan is taken while the patient is weight bearing.

[0022] According to any one of Examples 1 to 6 as well as another example ("Example 7"), the method further includes providing a relationship of the patient's levels of hip torsion and tibial torsion to predetermined levels of hip torsion and tibial torsion.

[0023] According to any one of Examples 1 to 7 plus another example ("Example 8"), the method further includes displaying the alignment of the lower limbs to a user, the alignment being displayed by superimposing the second axis, the third axis, and the fourth axis on the first axis.

[0024] According to one example ("Example 9"), a method for determining axial alignment of a lower extremity includes positioning a patient, scanning the patient's lower extremity to generate images including cross-sections in a frontal plane, a sagittal plane, and a transverse plane, obtaining a level of hip torsion based on the images, and obtaining a level of tibial torsion based on the images, wherein the level of hip torsion and the level of tibial torsion are mapped in three-dimensional space.

[0025] According to another example ("Example 10") in addition to Example 9, the method further includes aligning the image by viewing the image in the transverse plane through the patient's pelvis and at the level of the anterior iliac spine of the iliac crest, where aligning includes rotating the image in the transverse plane for symmetry.

[0026] According to another example ("Example 11") in addition to any one of Examples 9 to 10, the step of obtaining the level of hip torsion includes determining a femoral neck angle based on a position of a center of the femoral head relative to a center of the base of the femoral neck, where the position of the center of the femoral head and the position of the center of the base of the femoral neck are determined in three dimensional space in a first image set and a second image set, respectively, each of the first image set and the second image set including images in the coronal plane, the sagittal plane, and the transverse plane.

[0027] According to any one of Examples 9 to 11 plus another example ("Example 12"), the step of obtaining the level of hip torsion further includes determining a femoral distal angle based on a position of the medial femoral condyle or posterior position of the medial epicondyle relative to a posterior position of the lateral femoral condyle or lateral epicondyle, respectively, wherein the posterior position of the medial femoral condyle or posterior position of the medial epicondyle and the posterior position of the lateral femoral condyle or lateral epicondyle are determined in three dimensional space in a third image set and a fourth image set, respectively, each of the third image set and the fourth image set including images in the coronal plane, the sagittal plane, and the transverse plane.

[0028] According to any one of Examples 9 to 12 plus another example ("Example 13"), the step of obtaining the level of tibial torsion includes determining a proximal tibial angle relative to an axis of rotation of the proximal end of the tibia, the proximal tibial angle being based on a position of an anterior position of the medial tibial condyle relative to an anterior position of the lateral tibial condyle, the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle being determined in three dimensional space in a fifth image set and a sixth image set, respectively, each of the fifth image set and the sixth image set including images in the coronal plane, the sagittal plane, and the transverse plane.

[0029] According to another example ("Example 14") in addition to Example 13, the step of obtaining the level of tibial torsion includes determining a distal tibial angle associated with a line connecting the centers of a first tangent extending between the outermost lateral surfaces of the medial malleolus and a second tangent extending between the innermost medial surfaces of the lateral malleolus.

[0030] According to another example ("Example 15") in addition to Example 14, the step of determining tibial torsion includes determining a posterior position on the lateralmost lateral surface of the medial malleolus, an anterior position on the lateralmost lateral surface of the medial malleolus, a posterior position on the medialmost medial surface of the lateral malleolus, and an anterior position on the medialmost lateral surface of the medial malleolus in three dimensional space in a seventh image set, an eighth image set, a ninth image set, and a tenth image set, each of which includes images in the coronal plane, the sagittal plane, and the transverse plane.

[0031] According to one example ("Example 16"), a computer-implemented method for providing hip and tibial torsion values ​​includes receiving a plurality of images from a three-dimensional scan of at least one lower extremity of a patient, the images including a plurality of image sets, each of the image sets including an image in a coronal plane, an image in a sagittal plane, and an image in a transverse plane; identifying a femoral neck axis by identifying a center of the femoral head on a first image set and a center of a base of the femoral neck on a second image set; identifying a distal femoral axis of the patient's femur associated with an axis of rotation at a distal end of the femur, the distal femoral axis being determined in a third image set and a fourth image set; and determining an angle between the femoral neck axis and the distal femoral axis, the angle being determined in a fourth image set. identifying a proximal tibia axis associated with an axis of rotation of the patient's tibia at a proximal end of the tibia, the proximal tibia axis being determined in a fifth image set and a sixth image set; identifying a distal tibia axis associated with an axis of rotation of the patient's tibia at a distal end of the tibia, the proximal tibia axis being determined in a seventh image set, an eighth image set, a ninth image set, and a tenth image set; identifying an angle between the proximal tibia axis and the distal tibia axis, a neck axis and the distal femoral axis, the angle between the proximal tibia axis and the distal tibia axis being indicative of hip torsion.

[0032] According to another example ("Example 17") in addition to Example 16, the step of identifying the femoral neck axis includes providing a predetermined shape on the first set of three images and the second set of three images, the shape representing a three-dimensional shape.

[0033] According to another example ("Example 18") in addition to Example 17, the step of identifying the femoral neck axis includes sizing the shape to a maximum size that can be positioned within the base of the femoral neck such that the shape is shown in at least two images of the second image set to be in contact with the cortex of the base of the femoral neck.

[0034] According to any one of Examples 16 to 18 as well as another example ("Example 19"), the step of identifying the femoral neck axis includes finding the center of mass of the femoral head and the center of mass of the base of the femoral neck.

[0035] According to another example ("Example 20") in addition to any one of Examples 16 to 18, the step of identifying the femoral neck axis includes identifying and selecting the center of the femoral head and the center of the base of the femoral neck on the first image set and the second image set, the first image set and the second image set being selected from a plurality of image sets.

[0036] According to any one of Examples 16 to 18 as well as another example ("Example 21"), the steps of identifying the center of the femoral head, identifying the center of the base of the femoral neck, identifying the distal axis of the femur, identifying the proximal axis of the tibia, and identifying the distal axis of the tibia are accomplished by a computer system including a software module programmed to perform the identification based on prior training on multiple samples.

[0037] According to one example ("Example 22"), a computing device for providing hip torsion values ​​and tibial torsion values ​​includes one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the one or more processors to: identify a three-dimensional volume based on a scan of a patient's lower leg; determine a level of hip torsion by referencing a first axis of symmetry of a femoral neck and a second axis of symmetry of a distal part of the femur, where the hip torsion level is defined by an angle between the first axis of symmetry and the second axis of symmetry; determine a level of tibial torsion by referencing a third axis of symmetry of a proximal part of the tibia and a fourth axis of symmetry of a distal part of the tibia, where the tibial torsion level is defined by the angle between the third axis of symmetry and the fourth axis of symmetry; and provide the level of hip torsion and the level of tibial torsion to a user.

[0038] According to another example ("Example 23") in addition to Example 22, the step of determining the axis of symmetry of the femoral neck, the distal portion of the femur, the proximal portion of the tibia, and the distal portion of the tibia includes determining the axis of symmetry by reference to a two-dimensional or three-dimensional shape of the lower leg in an image from the scan.

[0039] According to another example ("Example 24") in addition to Example 22, the step of determining the axis of symmetry of the femoral neck, the distal portion of the femur, the proximal portion of the tibia, and the distal portion of the tibia includes determining the axis of symmetry by reference to a reference point on the lower leg in an image from the scan.

[0040] According to any one of Examples 22 to 24 plus another Example ("Example 25"), the angles between the first axis and the second axis are compared within a single plane.

[0041] According to any one of Examples 22 to 25 as well as another example ("Example 26"), the scan is a single scan of the entire lower extremity.

[0042] According to any one of Examples 22-26 as well as another example ("Example 27"), the scan is taken while the patient is weight bearing.

[0043] According to any one of Examples 22 to 27 as well as another example ("Example 28"), the method as implemented further includes providing a relationship of the patient's levels of hip torsion and tibial torsion to predetermined levels of hip torsion and tibial torsion.

[0044] According to any one of Examples 22 to 28 plus another example ("Example 29"), the method as implemented further includes displaying the alignment of the lower limbs to a user, the alignment being displayed by superimposing the second axis, the third axis, and the fourth axis on the first axis.

[0045] According to one example ("Example 30"), a non-transitory computer readable medium having computer readable instructions stored thereon for providing hip torsion values ​​and tibial torsion values, which, when executed by one or more processors of a computing device, cause the computing device to: identify a three dimensional volume based on a scan of a patient's lower leg; determine a level of hip torsion by referencing a first axis of symmetry of a femoral neck and a second axis of symmetry of a distal part of the femur, where the hip torsion level is defined by an angle between the first axis of symmetry and the second axis of symmetry; determine a level of tibial torsion by referencing a third axis of symmetry of a proximal part of the tibia and a fourth axis of symmetry of a distal part of the tibia, where the tibial torsion level is defined by the angle between the third axis of symmetry and the fourth axis of symmetry; and provide the level of hip torsion and the level of tibial torsion to a user.

[0046] According to another example ("Example 31") in addition to Example 30, the step of determining the axis of symmetry of the femoral neck, the distal portion of the femur, the proximal portion of the tibia, and the distal portion of the tibia includes determining the axis of symmetry by reference to a two-dimensional or three-dimensional shape of the lower leg in an image from the scan.

[0047] According to another example ("Example 32") in addition to Example 30, the step of determining the axis of symmetry of the femoral neck, the distal portion of the femur, the proximal portion of the tibia, and the distal portion of the tibia includes determining the axis of symmetry by reference to a reference point on the lower leg in an image from the scan.

[0048] According to any one of Examples 30 to 32 plus another Example ("Example 33"), the angles between the first axis and the second axis are compared within a single plane.

[0049] According to any one of Examples 30 to 33 as well as another example ("Example 34"), the scan is a single scan of the entire lower extremity.

[0050] According to any one of Examples 30-34 as well as another example ("Example 35"), the scan is taken while the patient is weight bearing.

[0051] According to any one of Examples 30 to 35 plus another example ("Example 36"), the method further includes providing a relationship of the patient's levels of hip torsion and tibial torsion to predetermined levels of hip torsion and tibial torsion.

[0052] According to any one of Examples 30 to 36 plus another example ("Example 37"), the method further includes displaying the alignment of the lower limb to a user, the alignment being displayed by superimposing the second axis, the third axis, and the fourth axis on the first axis.

[0053] The foregoing examples are merely examples and should not be read to limit or otherwise narrow the scope of any of the inventive concepts otherwise provided by this disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Thus, the drawings and detailed description are to be regarded as illustrative in nature, rather than restrictive in nature. [Brief description of the drawings]

[0054] The accompanying drawings are included to provide a further understanding of this disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the description, serve to explain the principles of the disclosure. [Figure 1] 1 is an illustration of a patient with reference planes and axes according to one embodiment. [Diagram 2] 1 is an illustration of a pelvis and a proximal femur according to one embodiment. [Figure 3A] 3 is an image of a scan shown in cross-section at the location shown in the cross-section of FIG. 2, according to one embodiment. [Figure 3B] 3B is an image of the aligned scans of FIG. 3A according to one embodiment. [Figure 4A] 1 is an illustration of a pelvis and a proximal femur with various planes shown at the femoral head according to one embodiment. [Figure 4B] 4B-4C are images of scans in various planes determined in FIG. 4A according to one embodiment. [Figure 4C] 4B-4C are images of scans in various planes determined in FIG. 4A according to one embodiment. [Figure 4D] 4B-4C are images of scans in various planes determined in FIG. 4A according to one embodiment. [Figure 5A] 1 is an illustration of a pelvis and proximal femur with various planes shown at the base of the femoral neck, according to one embodiment. [Figure 5B]5B-5C are images of scans in various planes determined in FIG. 5A according to one embodiment. [Figure 5C] 5B-5C are images of scans in various planes determined in FIG. 5A according to one embodiment. [Figure 5D] 5B-5C are images of scans in various planes determined in FIG. 5A according to one embodiment. [Figure 6A] 1 is an illustration of a proximal portion of a femur including a femoral neck according to one embodiment. [Figure 6B] 1 is an illustration of a proximal portion of a femur including a femoral neck according to one embodiment. [Figure 7A] 1 is an illustration of a distal portion of a femur with various planes shown at the lateral condyle according to one embodiment. [Figure 7B] 7B-7C are images of scans in various planes determined in FIG. 7A according to one embodiment. [Figure 7C] 7B-7C are images of scans in various planes determined in FIG. 7A according to one embodiment. [Figure 7D] 7B-7C are images of scans in various planes determined in FIG. 7A according to one embodiment. [Figure 8A] 1 is an illustration of a distal portion of a femur with various planes shown at the medial condyle according to one embodiment. [Figure 8B] 8B is an image of a scan in various planes determined in FIG. 8A according to one embodiment. [Figure 8C] 8B is an image of a scan in various planes determined in FIG. 8A according to one embodiment. [Figure 8D] 8B is an image of a scan in various planes determined in FIG. 8A according to one embodiment. [Figure 9A] 1 is an illustration of a proximal portion of a femur including a distal femoral shaft according to one embodiment. [Figure 9B] 1 is an illustration of a proximal portion of a femur including a distal femoral shaft according to one embodiment. [Figure 10A]1 is an illustration of a proximal portion of a femur including a femoral neck shaft and a femoral distal shaft according to one embodiment. [Figure 10B] 1 is an illustration of a proximal portion of a femur including a femoral neck shaft and a femoral distal shaft according to one embodiment. [Figure 11A] 1 is an illustration of a proximal tibia with various planes shown at the lateral condyle according to one embodiment. [Figure 11B] 11B is an image of a scan in various planes determined in FIG. 11A according to one embodiment. [Figure 11C] 11B is an image of a scan in various planes determined in FIG. 11A according to one embodiment. [Figure 11D] 11B is an image of a scan in various planes determined in FIG. 11A according to one embodiment. [Figure 12A] 1 is an illustration of a proximal tibia with various planes shown at the medial condyle according to one embodiment. [Figure 12B] 12B is an image of a scan in various planes determined in FIG. 12A according to one embodiment. [Figure 12C] 12B is an image of a scan in various planes determined in FIG. 12A according to one embodiment. [Figure 12D] 12B is an image of a scan in various planes determined in FIG. 12A according to one embodiment. [Figure 13] 1 is an illustration of a proximal portion of a tibia including a proximal tibia shaft according to one embodiment. [Figure 14A] 1 is an illustration of the distal tibia and fibula and the ankle joint with various planes shown at the anterior portion of the medial malleolus, according to one embodiment. [Figure 14B] 12B is an image of a scan in various planes determined in FIG. 12A according to one embodiment. [Figure 14C] 12B is an image of a scan in various planes determined in FIG. 12A according to one embodiment. [Figure 14D] 12B is an image of a scan in various planes determined in FIG. 12A according to one embodiment. [Figure 15A] 1 is an illustration of the distal tibia and fibula and the ankle joint with various planes shown at the dorsal aspect of the lateral malleolus, according to one embodiment. [Figure 15B] 15B is an image of a scan in various planes determined in FIG. 15A according to one embodiment. [Figure 15C] 15B is an image of a scan in various planes determined in FIG. 15A according to one embodiment. [Figure 15D] 15B is an image of a scan in various planes determined in FIG. 15A according to one embodiment. [Figure 16A] 1 is an illustration of the distal tibia and fibula and the ankle joint with various planes shown at the anterior portion of the lateral malleolus, according to one embodiment. [Figure 16B] 16B is an image of a scan in various planes determined in FIG. 16A according to one embodiment. [Figure 16C] 16B is an image of a scan in various planes determined in FIG. 16A according to one embodiment. [Figure 16D] 16B is an image of a scan in various planes determined in FIG. 16A according to one embodiment. [Figure 17A] 1 is an illustration of the distal tibia and fibula and the ankle joint with various planes shown at the dorsal aspect of the lateral malleolus, according to one embodiment. [Figure 17B] 17B-17C are images of scans in various planes determined in FIG. 17A according to one embodiment. [Figure 17C] 17B-17C are images of scans in various planes determined in FIG. 17A according to one embodiment. [Figure 17D] 17B-17C are images of scans in various planes determined in FIG. 17A according to one embodiment. [Figure 18A] 1A-1C are images and examples showing the medial and lateral malleolus axes, the medial and lateral malleolus axes, according to one embodiment. [Figure 18B] 1A-1C are images and examples showing the medial and lateral malleolus axes, the medial and lateral malleolus axes, according to one embodiment. [Figure 18C]1A-1C are images and examples showing the medial and lateral malleolus axes, the medial and lateral malleolus axes, according to one embodiment. [Figure 19] 1 is an illustration of a tibia including a proximal tibial axis and medial and lateral malleolus axes according to one embodiment. [Figure 20A] 1 is an image of a scan showing alignment of the scan according to one embodiment. [Figure 20B] 1 is an image of a scan showing alignment of the scan according to one embodiment. [Figure 21] 1 illustrates the calculation and registration of various angles defined by a patient's anatomy, according to one embodiment. [Figure 22] 1 illustrates the calculation and registration of various angles defined by a patient's anatomy, according to one embodiment. [Diagram 23] 1 illustrates various illustrations of hip and tibial torsion, according to various embodiments. [Figure 24] 1 illustrates various illustrations of hip and tibial torsion, according to various embodiments. [Diagram 25] 1 illustrates various illustrations of hip and tibial torsion, according to various embodiments. [Figure 26] 1 illustrates various illustrations of hip and tibial torsion, according to various embodiments. [Figure 27] 1 is an image of a scan showing alignment of the scan, according to one embodiment. [Figure 28] 1 shows an image of a scan showing the femoral head and femoral neck, according to one embodiment. [Figure 29] 1 shows an image of a scan showing the femoral head and femoral neck, according to one embodiment. [Diagram 30] 1 shows an image of a scan showing a distal portion of a femur, according to one embodiment. [Diagram 31] 1 shows an image of a scan showing a distal portion of a femur, according to one embodiment. [Diagram 32] 1 shows an image of a scan showing the proximal tibia, according to one embodiment. [Diagram 33] 1 shows an image of a scan showing the proximal tibia, according to one embodiment. [Diagram 34] 1 shows an image of a scan showing the distal portion of the tibia, according to one embodiment. [Diagram 35] 1 shows an image of a scan showing the distal portion of the tibia, according to one embodiment. [Diagram 36] 1 shows an image of a scan showing the distal portion of the tibia, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] [Detailed Description] [Definitions and Terminology] This disclosure is not meant to be read in a limiting manner, for example, the terminology used in the application should be read broadly in the context of the meaning that such terminology would have to one of ordinary skill in the art.

[0056] With respect to terminology of non-exactness, the terms "approximately" and "about" may be used interchangeably to refer to measurements that include the stated measurement and also include any measurements that are reasonably close to the stated measurement. A measurement that is reasonably close to a stated measurement deviates from the stated measurement by a reasonably small amount, as would be understood and readily appreciated by a person of ordinary skill in the relevant art. Such deviations may be due, for example, to errors in the measurements, differences in the calibration of measurements and / or manufacturing equipment, human error in reading and / or setting the measurements, minor adjustments made to optimize performance and / or construction parameters in light of differences in measurements associated with other components, specific implementation scenarios, imprecise alignment and / or manipulation of objects by humans or machines, and / or otherwise. Where it is determined that a person of ordinary skill in the relevant art would not readily appreciate the value of such reasonably small differences, the terms "approximately" and "about" may be understood to mean plus or minus 10% of the stated value.

[0057] According to reported studies, about 25% of knee replacement patients show dissatisfaction after knee replacement as judged by clinical and quality of life scores. One reason for dissatisfaction may be axial malalignment between the femoral and tibial components, resulting in patellofemoral tracking failure. The method discussed herein allows surgeons to obtain pre-operative and post-operative measurements that act as radiological biomarkers for both diagnosis and aid in guiding treatment.

[0058] Femoral torsion is described as the relationship between the distal femur and the femoral neck. Traditionally, the hip joint is anteverted by approximately 15° to approximately 20°. Retroversion is traditionally considered to be backwards. However, if the femoral rotation is 5° forward, this would still be referred to as anteversion. The terms "relative retroversion" and "relative hip retroversion" as used herein refer to a situation in which the hip joint is still pointing backwards by 5° to 10° compared to normal, still forward, but still relatively retroverted. As best understood, relative femoral retroversion is associated with labral tears, FAI, and ultimately hip OA.

[0059] There is a relationship between axial malalignment and flat feet. Traditionally, flat feet (planus) are treated with orthotic insoles (e.g., arch supports), suggesting that the underlying cause is in the foot. However, in a percentage of patients, the origin of the problem may be proximal, at the hip joint, or within the tibia, because axial malalignment leads to relative internal rotation of the ankle, which then leads to alignment at the subtalar joint. In effect, the subtalar joint everts as the tibia internally rotates, and the reciprocating motion at the Chopart joint places the foot in a flatter position. In these patients, orthotic insoles are less effective and may even worsen the condition by transmitting loads up the kinetic chain. For some patients, surgical correction of the axial malalignment, rather than insoles, may be the solution.

[0060] However, it is less clear how malalignment in hip torsion can affect joints or tissues below the hip and knee, such as the ankle, and conversely, how tibial torsion can affect joints or tissues above the ankle and knee, such as the hip. Preliminary data related to different pathologies suggests that malalignment can indeed cause problems in other joints, damage to other tissues, or reduced success of interventions. For example, hip retroversion or arthritis in the hip can lead to poor outcomes when performing ankle fusion. In another example, flat feet (or progressively collapsing foot deformity) can lead to hip joint pathology.

[0061] The present disclosure provides methods and systems for implementing methods for measuring alignment of the lower extremities (e.g., axial (transverse), coronal (frontal), and sagittal (bisect) alignment). In general, a method for determining axial alignment of a lower extremity may include identifying a three-dimensional volume based on a scan of a patient's lower extremity; determining a level of hip twist by referencing a first plurality of reference points in the three-dimensional volume associated with a femoral neck and a second plurality of reference points associated with a distal portion of the femur, where the hip twist level is defined by a relationship between the first and second plurality of reference points; determining a level of tibial twist by referencing a third plurality of reference points in the three-dimensional volume associated with a proximal portion of the tibia and a fourth plurality of reference points associated with a distal portion of the tibia, where the tibial twist level is defined by a relationship between the third and fourth plurality of reference points; and providing the level of hip twist and the level of tibial twist to a user.

[0062] In some embodiments, the method includes providing a first line generally representing an axis of the femoral neck, the first line generally coinciding with the first plurality of reference points (e.g., the first line is defined by at least two of the plurality of reference points), and a second line generally representing an axis of rotation of the distal portion of the fibula, the second line generally corresponding to the second plurality of reference points (e.g., the second line is defined by at least two of the plurality of reference points). In some embodiments, the method may include providing a third line generally representing an axis of rotation of the proximal portion of the tibia, the third line generally corresponding to the third plurality of reference points (e.g., the third line is defined by at least two of the plurality of reference points), and a fourth line generally representing an axis of rotation of the distal portion of the tibia, the fourth line generally corresponding to the fourth plurality of reference points (e.g., the fourth line is defined by at least two of the plurality of reference points). In some embodiments, the method includes calculating an angle between the first line and the second line and calculating an angle between the third line and the fourth line.

[0063] Various methods described herein may be implemented to identify reference points, lines, and angles, which may be implemented either alone or in combination with various embodiments described. For example, in some embodiments, unique anatomical locations (e.g., femoral head, center of condyle, etc.) may be determined and their locations recorded as reference points. It is understood that the locations and reference points as described herein may be used interchangeably to discuss actual anatomical locations in addition to indicators or data as recorded by a system implementing these methods. These various methods may generally include identifying unique anatomical locations. The anatomical locations may be determined within a three-dimensional volume defined with reference to a three-dimensional scan of the patient's lower leg. This may be accomplished by determining each location by reviewing images provided from the scan or by reviewing a three-dimensional model provided from the scan. When reviewing the images, a single location may be determined in at least two images in different planes. For example, a single location may be determined in three images, the three images being in three planes (e.g., coronal, sagittal, and transverse). Upon examination of a three-dimensional model, these locations may be determined directly within the three-dimensional model. These methods will be more fully explained, and it will be understood that the general concepts described herein may be implemented with respect to any of the unique locations discussed hereinafter.

[0064] FIG. 1 is provided to clearly illustrate various planes and axes as they relate to the human body, which are discussed throughout this disclosure. More specifically, this disclosure relates to a method for assessing the degree of axial malalignment (e.g., in the transverse plane) for both diagnostic and / or direct therapeutic aid. The method may be implemented using a system as described herein or on other systems capable of performing similar steps or providing similar output. The systems and methods discussed herein provide an accurate and reproducible way of identifying a patient's hip and tibial torsion. FIG. 1 illustrates a patient's body 2 having a left leg 4 and a right leg 6. A frontal plane 10 is indicated by a long dashed line relative to the patient's body 2, a transverse plane 12 is indicated by a dashed and dotted line relative to the patient's body 2, and a sagittal plane 14 is indicated by a short dashed line relative to the patient's body 2. All figures including representations of the coronal, transverse and sagittal planes 10, 12 and 14 planes include the same dashed line features throughout for each of those planes. Each of the coronal, longitudinal and sagittal axes 16, 18 and 20 are shown relative to the patient's body 2. The planes 10, 12 and 14 and axes 16, 18 and 20 are discussed throughout and the positions shown in FIG. 1 do not represent the exact locations of these planes and axes, but are instead shown as a guide for orientation. It is understood that other terms are applicable for similar or equivalent concepts and the terms implemented herein are not intended to be limiting in scope. For example, the term "coronal plane" may also be understood as "coronal plane".

[0065] In some embodiments, a computed tomography ("CT") scan is taken of the patient, which provides an image of the patient in slices representing the patient's anatomy in three different planes (i.e., axial, sagittal, and coronal). Although CT scans are discussed throughout, it is understood that other imaging techniques may be utilized in the methods described herein (e.g., magnetic resonance imaging). A method of determining the axial alignment of the lower extremities may include positioning the patient, scanning the patient's lower extremities to generate images including cross-sections in the frontal plane, the sagittal plane, and the transverse plane, obtaining a level of hip torsion based on the images, and obtaining a level of tibial torsion based on the images. The scans are taken in various formats, including weight-bearing scans or supine scans. It is generally understood that the scans discussed herein relate to a single scan of one entire lower extremity or a single scan of both entire lower extremities. Although multiple scans may be implemented in the methods and systems described herein, it is understood that in some embodiments a single scan will provide a more accurate view of the alignment of the lower extremity than multiple scans, as typically, user movement between scans will result in inaccurate measurements of alignment between the various positions discussed herein.

[0066] In some embodiments, the method includes aligning the images and / or data sets prior to determining the axial alignment of the lower extremities. For example, and with reference to FIGS. 2, 3A, and 3B, the data sets are aligned for best possible symmetry when projected onto the coronal plane (e.g., the images show cross-sections in the transverse plane 12). This allows for comparison of angular measurements between the left lower extremity 4 and the right lower extremity 6. Alignment of the data sets and / or images is completed by viewing an image (e.g., an axial slice) in the transverse plane 12 through the patient's pelvis 22 and at the level of the anterior iliac spine of the iliac crest, and aligning includes rotating the image in the transverse plane 12 for symmetry. For example, FIG. 2 clearly shows where an axial slice may be viewed (i.e., an axial slice in the transverse plane 12). 2, a femur 24 is shown, including a femoral head 26, a femoral neck 28, and a femoral neck base 30. FIG. 3A shows an axial slice at the location shown in FIG. 2 (i.e., at the level of the anterior iliac spine of the iliac crest), which shows the spinal segment off-axis. The data set is then rotated so that the axial slice showing the spinal segment is aligned to show symmetry (e.g., bilateral symmetry or symmetry about the sagittal plane). Once the data set is aligned, a user (e.g., a physician, radiologist, medical professional, etc.) and / or a system (e.g., an automated or semi-automated program running on a computer) may specify the axial alignment of one or more of the lower extremities. Once alignment is completed for the images and data set, the axial alignment may be specified for one or both lower extremities.

[0067] Turning attention to the discussion of identifying the level of hip torsion, FIGS. 4A-10B demonstrate how hip torsion is calculated. For reference, FIGS. 10A and 10B demonstrate two anatomically representative lines as they relate to the natural anatomy of the patient's femur. The angular relationship between these two anatomically representative lines provides the level of hip torsion. A first anatomically representative line indicates the femoral neck axis 32 and a second anatomically representative line indicates the femoral distal axis 34. FIGS. 4A-6B demonstrate how the femoral neck axis 32 is identified and FIGS. 7A-9B demonstrate how the femoral distal axis 34 is identified. Although lines are discussed herein, it is understood that the methods and systems discussed herein may be implemented with vectors or other representations corresponding to the axes discussed herein, whichever is appropriate.

[0068] Referring to FIG. 4A, an exemplary pelvis 22 and proximal end of a femur 24 are illustrated. To identify the level of hip torsion, a femoral neck angle is identified by defining the location of the femoral neck axis 32. The femoral neck axis 32, and therefore the femoral neck angle, is based on the location of the center of the femoral head 26 relative to the center of the base of the femoral neck 28. The locations of the various planes 10, 12, and 14 in FIG. 4A represent the locations corresponding to the axial slices (e.g., three image sets with one image in each plane) of FIGS. 4B-4D. Thus, FIGS. 4A-4D are relative to the femoral head 26. To identify the femoral neck axis 32, the center of the femoral head 26 is located. The center of the femoral head is determined by correlating the centers in three-dimensional space by determining the centers in a first image in the coronal plane 10 (i.e., FIG. 4B), a second image in the sagittal plane 14 (i.e., FIG. 4C), and a third image in the transverse plane 12 (i.e., FIG. 4D). The center of the head 26 of the femur 24 can be determined in a variety of ways. In some embodiments, the center of mass of the head 26 of the femur 24 can be determined using mathematical analysis. In some embodiments, the center of the head 26 of the femur 24 can be determined by providing a predetermined three-dimensional shape in the data set that would fall within the femoral head 26. For example, a sphere may be represented in the data set, which appears as a circle on the axial slice being viewed by the user. It will be understood that any suitable shape may be implemented, and a sphere is provided only as an example. The user and / or the system may size the sphere so that it fits or sits within the cortex of the femoral head 26. As the sphere relates to the axial slices, the sphere, represented as a circle on each of the axial slices, is positioned within the cortex of the femoral head 26. Once the circle in each of the axial slices is positioned within the femoral head 26, the center of the sphere (e.g., the center of the circle in each of the coronal, transverse, and sagittal planes) is defined as the center of the femoral head 26.

[0069] In some embodiments, locating the center of the femoral head 26 is accomplished via a method (e.g., a computer-implemented method) that allows a user to identify the center of the femoral head 26 by correlating frontal, transverse, and sagittal slices from the data set, which are represented by images in each of the frontal, transverse, and sagittal planes. For example, FIG. 4B represents an image in the frontal plane 10. A sphere is represented in the frontal plane 10 by a circle in the image of FIG. 4B. The other planes (transverse plane 12 and sagittal plane 14) are provided for reference as lines that are also illustrated in FIG. 4B. As can be seen in FIG. 4B, a circle representing the sphere in the two-dimensional image is shown as a long dashed line in the frontal plane 10. In FIG. 4C, a circle representing the sphere in the two-dimensional image is shown as a short dashed line in the sagittal plane 14. The other planes (frontal plane 10 and transverse plane 12) are provided for reference as lines that are also illustrated in FIG. 4C. In Figure 4D, a circle representing a sphere in a two-dimensional image is shown as a dashed line in transverse plane 12. The other planes (coronal plane 10 and sagittal plane 14) are provided for reference as are the lines also illustrated in Figure 4D. The circle in each of Figures 4B-4D falls within the cortex of the femoral head 26.

[0070] In some embodiments, identification of the femoral neck base 30 is accomplished via a method (e.g., a computer-implemented method) that allows a user to identify the center of the femoral neck base 30 by correlating frontal, transverse, and sagittal slices from a data set (e.g., a set of three images in each plane), which slices are represented by images in each of the frontal, transverse, and sagittal planes. The center of the femoral neck base 30 is identified by correlating the center in three-dimensional space by identifying the center in the fourth image in the frontal plane 10 (i.e., FIG. 5B), the fifth image in the sagittal plane 14 (i.e., FIG. 5C), and the sixth image in the transverse plane 12 (i.e., FIG. 5D). The locations of the various planes 10, 12, and 14 can be seen in FIG. 5A and represent locations corresponding to the axial slices of FIGS. 5B-5D, all of which are associated with the femoral neck base 30. Referring to FIG. 5B, the sphere is represented in the frontal plane 10 by a circle in the image of FIG. 5B. The other planes (transverse plane 12 and sagittal plane 14) are provided for reference as lines also illustrated in FIG. 5B. As can be seen in FIG. 5B, the circle representing the sphere in the two-dimensional image is shown as a long dashed line in the frontal plane 10. In FIG. 5C, the circle representing the sphere in the two-dimensional image is shown as a short dashed line in the sagittal plane 14. The other planes (frontal plane 10 and transverse plane 12) are provided for reference as lines also illustrated in FIG. 5C. In FIG. 5D, the circle representing the sphere in the two-dimensional image is shown as a dashed line in the transverse plane 12. The other planes (frontal plane 10 and sagittal plane 14) are provided for reference as lines also illustrated in FIG. 5D. The circles in each of FIG. 5B-5D fall within the cortex of the femoral neck base 30. 5B-5D represent a single point in three-dimensional space. That single point represents the center of a sphere that locates the center of the femoral neck base 30.

[0071] 6A and 6B, once the center of the femoral head 26 has been located and the center of the femoral neck base 30 has been located, the femoral neck axis 32 can be located. The femoral neck axis 32 extends between the center of the femoral head 26 and the center of the femoral neck base 30 (e.g., along and through the center of the femoral neck 28). To determine hip torsion, i.e., the angle between the femoral neck axis 32 and the distal femoral axis 40 (see, e.g., FIGS. 9A and 9B), FIGS. 10A and 10B show the relationship between the femoral neck axis 32 and the distal femoral axis 40 in more detail.

[0072] 7A-9B, the femoral distal axis 34 generally represents the axis of rotation of the distal part of the femur 24 or an axis parallel to that axis of rotation. The distal part of the femur 24 generally rotates along a curved surface of both condyles on the distal face, the center point of which is defined by the condyles generally representing the axis of rotation. The surfaces of the condyles define a contact position and are therefore generally parallel to the axis of rotation of the distal part of the femur 24. Thus, one way to identify the femoral distal axis 34 is to identify a line extending between the condyles of the distal part of the femur 24. On a three-view view, the marker in the coronal plane is located at the level of the upper edge of the femoral recess (which corresponds to the most prominent distal femoral posterior condylar element).

[0073] More specifically, referring to FIG. 7A, a distal portion of the femur 24 is illustrated, including a lateral femoral condyle 36 and a medial femoral condyle 38. The locations of the various planes 10, 12, and 14 in FIG. 7A represent corresponding locations of axial slices (e.g., a three image set with one image in each plane) in FIG. 7B-7D. Based on the locations of the axial slices shown in FIG. 7A, FIG. 7A-7D relate to the medial femoral condyle 38. To identify the distal femoral axis 34, a predetermined location is identified on the lateral femoral condyle 36. For example, as shown in FIG. 7A-7D, the apex 36a of the lateral femoral condyle 36 is identified at a dorsal location of the femur 24. The apex 36a can be identified and correlated in each of three images in the various planes (e.g., a three image set in each of the planes 10, 12, and 14). By correlating the position of the apex 36a in the three images, a three-dimensional position for the apex 36a of the lateral femoral condyle 36 is obtained.

[0074] With reference to FIG. 8A, a distal portion of the femur 24 is illustrated, including a lateral femoral condyle 36 and a medial femoral condyle 38. The locations of the various planes 10, 12, and 14 in FIG. 8A represent corresponding locations of axial slices (e.g., a three image set with one image in each plane) in FIG. 8B-8D. Based on the locations of the axial slices shown in FIG. 8A, FIG. 8A-8D relate to the medial femoral condyle 38. To identify the distal femoral axis 34, a predetermined location on the medial femoral condyle 38 is identified. For example, as shown in FIG. 8A-8D, at a dorsal location of the femur 24, the apex 38a of the medial femoral condyle 38 is identified. The apex 38a can be identified and correlated in each of three images in the various planes (e.g., a three image set in each of the planes 10, 12, and 14). By correlating the position of the apex 38a in the three images, a three-dimensional position for the apex 38a of the medial femoral condyle 38 is obtained.

[0075] 9A and 9B, once the apexes 36a and 38a of the lateral and medial condyles 36, 38 have been indexed dorsally on the distal portion of the femur 24, a distal femoral axis 34 can be identified. The distal femoral axis 34 extends between the apexes 36a and 38a of the lateral and medial condyles 36, 38. The distal femoral axis 34 is generally parallel to the axis of rotation of the distal portion of the femur 24. The distal femoral axis 34 as identified in the described method generally represents the femoral condyle axis when represented in an axial plane.

[0076] 10A and 10B, the level of hip torsion may then be calculated by determining the relationship between the femoral neck axis 32 and the distal femoral axis 34. More specifically, the angular relationship is of interest in determining the level of hip torsion. For example, hip torsion may be defined as the relationship between the femoral neck axis 32 and the distal femoral axis 34 in the transverse plane. When the femoral neck axis 32 is anterior to the distal femoral axis 34 in the transverse plane, the orientation is referred to as anteversion. Otherwise, the relationship between the femoral neck axis 32 and the distal femoral axis 34 is referred to as retversion and is expressed in degrees.

[0077] It is understood that the methods described throughout may include defining a three-dimensional space in which the described points may be mapped. The three-dimensional space may include a coordinate system in which each of the described points and locations may be defined. For example, the center of the femoral head 26 may be assigned a predetermined coordinate in the coordinate system (X, Y, and Z values ​​to describe a three-dimensional location in the coordinate system), the center of the femoral neck base 30 may be assigned a predetermined coordinate in the coordinate system, the apex 36a of the lateral femoral condyle 36 may be assigned a predetermined coordinate in the coordinate system, and the apex 38a of the medial femoral condyle 38 may be assigned a predetermined coordinate in the coordinate system. The femoral neck axis 32 and the distal femoral axis 34 may be mapped in the coordinate system. In this manner, the relationship between the femoral neck axis 32 and the distal femoral axis 34 may be easily understood and calculated based on the coordinate system.

[0078] In another embodiment, and with reference to FIGS. 20A and 20B, hip torsion can be identified by manually drawing a line from the center of the femoral head 26 to the central bisection point between the proximal femoral condyles (corresponding to the center of the femoral neck 28). A second line is drawn parallel to the distal femoral condyles 36 and 38 in the transverse plane at the level of the mid-knee condyles in the coronal plane. These images and lines are then superimposed on each other. There are two methods that can be used: either directly measuring the bones at once on two different axial slices (one at hip level and one at knee level) or taking two separate angle measurements using a horizontal line as a static reference on either slice and subsequently adding or subtracting the resulting angles depending on the orientation / direction of the bone. The angle between the drawn lines is recorded in degrees as a measure of hip torsion. If this angle is anterior, it is known as hip anteversion. When this angle is posterior, it is known as hip retroversion.

[0079] 11A-19, a method for identifying tibial torsion is provided. Tibial torsion is defined as the angle between a line connecting both posterior condyles of the tibia (i.e., the proximal tibial axis 46) and a line bisecting the articular surfaces of the medial and lateral malleolus, i.e., the medial-lateral malleolus axis 48 (hereinafter, "TMA"). The TMA 48 is related to the distal tibial angle and therefore may be used interchangeably throughout. Additional lines are drawn along the most prominent point of the medial third of the tibial tuberosity and the TMA. Determining these positions is described in more detail herein.

[0080] 11A-13, the location of the proximal tibial axis 46 is illustrated. For example, the proximal end of the tibia 50 is shown. The proximal end of the tibia 50 includes a lateral posterior tibial condyle 52 and a medial posterior tibial condyle 54. The proximal tibial axis 46 is defined between similar locations on each of the lateral posterior tibial condyle 52 and the medial posterior tibial condyle 54. The proximal tibial axis 46 generally represents the axis of rotation of the proximal portion of the tibia 50, or an axis parallel to the axis of rotation. The proximal portion of the tibia 50 generally rotates along a curved surface of both condyles on the proximal face, with the center point of the curved surface defined by the condyles generally representing the axis of rotation. The surfaces of both condyles define a contact location and are therefore generally parallel to the axis of rotation of the proximal portion of the tibia 50. Therefore, one way to identify the proximal tibia axis 46 is to identify a line extending between the condyles of the proximal portion of the tibia 50 .

[0081] As previously discussed, a three-dimensional scan of the patient's lower leg is taken. Images and / or data generated by the three-dimensional scan can be used to identify or define locations (either through manual or automated processes) within the data and / or images. In some embodiments, the images are centered around the patient's knee. A three-dimensional location of a set of three images of the proximal portion of the tibia 50 is first provided in the coronal plane, approximately 1 mm proximal to the fibular head (e.g., one slice above the fibular head).

[0082] More specifically, referring to FIG. 11A, a proximal portion of a tibia 50 is illustrated, including a lateral tibial posterior condyle 52 and a medial tibial posterior condyle 54. The locations of the various planes 10, 12, and 14 in FIG. 11A represent the locations corresponding to the axial slices (e.g., a three image set with one image in each plane) of FIGS. 11B-11D. Based on the locations of the axial slices shown in FIG. 11A, FIGS. 11A-11D relate to the lateral tibial posterior condyle 52. To identify the proximal tibial axis 46, a predetermined location on the lateral tibial posterior condyle 52 is identified. For example, as shown in FIGS. 11A-11D, at a dorsal location of the tibia 50, the apex 52a of the lateral tibial posterior condyle 52 is identified. The apex 52a can be identified and correlated in each of the three images in various planes (e.g., a set of three images in each of planes 10, 12, and 14). By correlating the position of the apex 52a in the three images, a three-dimensional position for the apex 52a of the lateral posterior tibia condyle 52 is obtained.

[0083] With reference to FIG. 12A, a proximal portion of a tibia 50 is illustrated, including a lateral tibial posterior condyle 52 and a medial tibial posterior condyle 54. The locations of the various planes 10, 12, and 14 in FIG. 12A represent the locations corresponding to the axial slices of FIGS. 12B-12D (e.g., a three image set with one image in each plane). Based on the locations of the axial slices shown in FIG. 12A, FIGS. 12A-12D relate to the medial tibial posterior condyle 54. To identify the proximal tibial axis 46, a predetermined location on the medial tibial posterior condyle 54 is identified. For example, as shown in FIGS. 12A-12D, at a dorsal location of the tibia 50, the apex 54a of the medial tibial posterior condyle 54 is identified. The apex 54a can be identified and correlated in each of the three images in the various planes (e.g., a three image set in each of the planes 10, 12, and 14). By correlating the position of the apex 38a in the three images, a three-dimensional position for the apex 52a of the tibial medial posterior condyle 54 is obtained.

[0084] 13, once the apexes 52a and 54a of the lateral and medial tibial posterior condyles 52, 54 have been indexed dorsally on the proximal portion of the tibia 50, the proximal tibial axis 46 can be identified. The proximal tibial axis 46 extends between the apexes 52a and 54a of the lateral and medial tibial posterior condyles 52, 54. The proximal tibial axis 46 is generally parallel to the axis of rotation of the proximal portion of the tibia 50. The proximal tibial axis 46 as identified in the described method generally represents the tibial condyle axis when represented in an axial plane.

[0085] 14A-18C, the location of the TMA 48 is identified by locating various anatomical locations relative to the patient's ankle. As previously discussed, the TMA 48 is relative to an axis extending between the bisecting points of the medial malleolar axis 60 and the lateral malleolar axis 62. Because each of the medial malleolar axis 60 and the lateral malleolar axis 62 is required to identify the TMA 48, an explanation of how the medial malleolar axis 60 and the lateral malleolar axis 62 are identified and defined is provided herein.

[0086] 14A-15D, a location defining the medial malleolus axis 60 is provided. More specifically, FIGS. 14A and 14A' show rear and front views, respectively, of the distal portion of the tibia 50 and the distal portion of the fibula 51, the same views being provided in FIGS. 15A, 15A', 16A, 16A', 17A, and 17A' and orienting the location shown in the associated images. More specifically, referring to FIGS. 14A-15D, to identify the medial malleolus axis 60, a location relative to the structure of the medial malleolus 64 is determined. The structure of the medial malleolus 64 in combination with the lateral malleolus 66 of the fibula 51 may be implemented to determine the axis of rotation of the distal portion of the tibia 50 as it relates to the ankle joint, and thus define the TMA 48.

[0087] In some embodiments, the medial malleolar axis 60 may be generally defined between the anterior medial malleolar margin 64a and the dorsal medial malleolar margin 64b. Referring to FIGS. 14A-14D, the distal end of the tibia 50 is shown and these views generally relate to the anterior medial malleolar margin 64a. The positions of the various planes 10, 12, and 14 in FIG. 14A represent the positions corresponding to the axial slices (e.g., a three-image set with one image in each plane) of FIGS. 14B-14D. As indicated by the positions of the axial slices shown in FIG. 14A, FIGS. 14A-14D illustrated the position of the anterior medial malleolar margin 64a. To obtain the views shown in FIGS. 14B-14D, the positions at which the images and / or data of the three-dimensional scan are provided are such that the three planes 10, 12, and 14 intersect at a coronal level approximately 1 mm distal to a line drawn across the upper portion of the talar cortical surface 80. It will be appreciated that in the event that the talus is abnormally positioned (e.g., if the talus is tilted following a ligament injury), images and / or data may be provided such that the sagittal plane 14 is approximately parallel to the distal tibial articular surface. To identify the medial malleolus axis 60, a predetermined location on the anterior medial malleolus 64a is identified. The anterior medial malleolus 64a may be identified and correlated in each of three images in various planes (e.g., a set of three images in each of planes 10, 12, and 14). By correlating the location of the anterior medial malleolus 64a in the three images, a three-dimensional location for the anterior medial malleolus 64a of the medial malleolus is obtained.

[0088] 15A-15D, the distal end of the tibia 50 is shown and these figures are generally related to the dorsal medial malleolar edge 64b. The locations of the various planes 10, 12, and 14 in FIG. 15A represent the locations corresponding to the axial slices (e.g., a three-image set with one image in each plane) of FIG. 15B-15D. As indicated by the locations of the axial slices shown in FIG. 15A, FIG. 15A-15D illustrated the location of the dorsal medial malleolar edge 64b. The locations at which the images and / or data of the three-dimensional scan are provided to obtain the views shown in FIG. 15B-15D may be similar to those provided in connection with FIG. 14A-14D. To identify the medial malleolar axis 60, a predetermined location on the dorsal medial malleolar edge 64b is identified. The dorsal medial malleolar edge 64b can be identified and correlated in each of the three images in the various planes (e.g., a three-image set in each of the planes 10, 12, and 14). By correlating the position of the dorsal medial malleolus 64b in the three images, a three-dimensional position for the dorsal medial malleolus 64b is obtained.

[0089] Once the anterior medial malleolus margin 64 a and the posterior medial malleolus margin 64 b have been determined, a medial malleolus axis 60 is defined between the two locations associated with the anterior medial malleolus margin 64 a and the posterior medial malleolus margin 64 b. As previously discussed with respect to other axes, the medial malleolus axis 60 can be determined in a three-dimensional coordinate system.

[0090] The method for identifying the lateral malleolar axis 62 may be similar to the method for identifying the medial malleolar axis 60. For example, referring to FIGS. 16A-16D, the distal end of the tibia 50 is shown, and these figures generally relate to the anterior lateral malleolar edge 66a. The locations of the various planes 10, 12, and 14 in FIG. 16A represent the locations corresponding to the axial slices (e.g., a three-image set with one image in each plane) of FIGS. 16B-16D. As indicated by the locations of the axial slices shown in FIG. 16A, FIGS. 16-16D illustrated the location of the anterior lateral malleolar edge 66a. The locations at which the images and / or data of the three-dimensional scan are provided to obtain the views shown in FIGS. 16B-16D may be similar to those provided in connection with FIGS. 14A-14D. To identify the lateral malleolar axis 62, a predetermined location on the anterior lateral malleolar edge 66a is identified. The anterior lateral malleolus 66a can be located and correlated in each of the three images in various planes (e.g., a set of three images in each of planes 10, 12, and 14). By correlating the location of the anterior lateral malleolus 66a in the three images, a three-dimensional location for the anterior lateral malleolus 66a of the lateral malleolus is obtained.

[0091] 17-17D, the distal end of the tibia 50 is shown and these views are generally related to the dorsal lateral malleolus 66b. The locations of the various planes 10, 12, and 14 in FIG. 17A represent the locations corresponding to the axial slices (e.g., a three-image set with one image in each plane) of FIG. 17B-17D. As indicated by the location of the axial slices shown in FIG. 17A, FIG. 17-17D illustrated the location of the dorsal lateral malleolus 66b. The locations at which the images and / or data of the three-dimensional scan are provided to obtain the views shown in FIG. 17B-17D may be similar to those provided in connection with FIG. 14A-14D. To identify the lateral malleolus axis 62, a predetermined location on the dorsal lateral malleolus 66b is identified. The dorsal lateral malleolus 66b can be identified and correlated in each of the three images in the various planes (e.g., a three-image set in each of the planes 10, 12, and 14). By correlating the position of the dorsal lateral margin 66b in the three images, a three-dimensional position for the dorsal lateral margin 66b of the lateral malleolus is obtained.

[0092] Once the anterior lateral malleolus margin 66 a and the posterior lateral malleolus margin 66 b have been determined, a lateral malleolus axis 62 is defined between the two locations associated with the anterior lateral malleolus margin 66 a and the posterior lateral malleolus margin 66 b. As discussed above with respect to the other axes, the lateral malleolus axis 62 can be determined in a three-dimensional coordinate system.

[0093] 18A-18C , once the medial malleolar axis 60 and the lateral malleolar axis 62 have been determined, the TMA 48 is defined. The TMA 48 is defined between the medial malleolar axis 60 and the lateral malleolar axis 62, with the TMA 48 extending from the midpoint of each of the medial malleolar axis 60 and the lateral malleolar axis 62. As previously discussed with respect to the other axes, the TMA 48 can be determined in a three-dimensional coordinate system.

[0094] 19, the proximal tibia axis 46 can be seen relative to the TMA 48. Tibial torsion is determined by calculating the relative angle defined between the proximal tibia axis 46 and the TMA 48. If the torsion is oriented externally relative to the sagittal plane, it is known as tibial external rotation. If the torsion is oriented internally relative to the sagittal plane, it is known as tibial internal rotation.

[0095] In some embodiments, and with reference to FIGS. 21 and 22, measurements can be calculated to identify hip and tibial torsion. In some embodiments, a two-dimensional angle calculation can implement a vector match (i.e., dot product or cosine law) to generate six individual angle values ​​between the horizontal line and each of the six lines drawn. The two-dimensional angle calculation may implement measurements shown in the sagittal plane, or may be simplified from the positions determined in the methods provided herein to only view the relative angles in a single plane. In other embodiments, angle measurements can be measured in three-dimensional space, as discussed throughout, and a vector dot product or cosine law can be used to calculate each of the hip and tibial torsion individually, and then the relationship between the hip and tibial torsion can be calculated.

[0096] It is understood that the methods described herein may be accomplished manually or may be provided via an automated system. The methods described herein provide intra- and inter-operator reliability between calculations. In some embodiments, the methods described herein may be implemented in an automated system where the selection and determination of the described locations may be performed by a processor. The processor may be trained using artificial intelligence and deep learning approaches to determine the locations described herein or other locations and anatomical features that generally provide coordinates or reference points for identifying hip and tibial torsion.

[0097] These coordinates and / or fiducials, whether identified manually or through an automated process, may be mapped within the three-dimensional space. For example, the scans discussed herein may be used to provide and define the three-dimensional volume. The various axes discussed herein (e.g., femoral neck axis, distal femoral axis, proximal tibia axis, and distal tibia axis) may be provided within the three-dimensional volume. These various axes may be represented within the three-dimensional volume by vectors that may align with and be coextensive with these axes (e.g., starting and ending at locations described herein) or that may be provided as aligning with and extending beyond the locations defining the axes. Thus, in some embodiments, vectors are used to map or represent relevant axes within the three-dimensional volume as they relate to the data points used to identify hip and tibial torsion. In some embodiments, the scans may be used to construct a three-dimensional model of the patient's lower extremity, which may be implemented to select the various locations described herein (either alone or in combination with the images or slices described herein) rather than relying solely on the images or slices described herein.

[0098] It will be appreciated that the relationships between each of the anatomical locations described herein may be represented or provided to the user in different formats. For example, when lines are implemented to represent the femoral neck angle (e.g., a first line), the distal femoral angle (e.g., a second line), the proximal tibial angle (e.g., a third line), and the distal tibial angle (e.g., a fourth line), the relationships between these lines may be provided to the user in various formats (e.g., percentages, degrees, etc.). Additionally, when a first line and a second line are implemented to provide a hip torsion value, the angle between the first line and the second line may be provided as an angle in a single plane (e.g., the coronal plane) or as the actual angle between the two. For example, because the angle between a first line and a second line may have components in each of the X, Y, and Z axes, the angle between the lines may vary depending on how the relationship is viewed (e.g., depending on whether the relationship between the two is viewed in a single plane or in a three-dimensional volume, or, if the relationship is provided in a single plane, depending on which plane is implemented). In some embodiments, the angle between a first line and a second line is provided as a relationship between the two in a single plane because the relationship provides a level of hip twist that is commonly used in medical practice.

[0099] Once both the patient's hip and tibial torsion are identified, a relative difference in the patient's hip torsion compared to a baseline hip torsion and a relative difference in the patient's tibial torsion compared to a baseline tibial torsion are determined. The baseline hip and tibial torsions may be based on population averages, may be provided based on subgroups of the population such as age, sex, and height, or may be provided based on factors including optimal anatomical and / or biomechanical factors.

[0100] 21 and 22, a method for identifying hip and tibial torsion may include using data acquired from a High-Rise™ Scanner (Curvebeam®, PA, USA) where various axial slices through the hip, knee and ankle are examined. The data is conventionally displayed on a screen or viewer with right-hand data on the left hand side and left-hand data on the right, as if viewed from opposite positions. On all images, a reference line is drawn to the horizontal, because this then takes into account pelvic rotation, and all lines are referenced to the horizontal.

[0101] 23-26 provide examples of hip and tibial torsion. To refer to the drawings, various identifiers are provided and are defined as follows:

[0102] Functional Axis of the Lower Limb (MAL) - This is the center of the femoral head to the center of the tibial roof. The corrected MAL is measured from the center of the femoral head to the weight-bearing point of the calcaneus (aMAL).

[0103] Hip Knee Angle (HKA) - Draw a line from the center of the femoral head to the femoral intercondylar notch (line A below). Draw a second line from the tibial interspinous point to a midpoint on the distal tibia roof (line B below). The HKA is defined as the angle between these two lines.

[0104] Proximal Femoral Lateral Angle (LPFA) - First, draw a line from the superior point of the greater trochanter to the center of the femoral head. Then draw a second line (line A below) from the center of the femoral head to the femoral intercondylar notch. The line connecting these two is the LPFA and is usually 90 degrees.

[0105] The medial lateral femoral angle to functional axis (mLDFA), also called the femoral functional axis-anatomical axis (FMA) angle, is the intersection of a line drawn from the center of the femoral head to the femoral intercondylar notch (line A below) and a second line drawn across the distal-most portions of the medial and lateral femoral condyles.

[0106] Proximal Medial Tibial Angle (MPTA) - Also called the Tibial Functional Axis (TMA). First, draw a line from the tibial interspinous point to a midpoint on the distal tibia roof (line B). Draw a second line from the most proximal medial area of ​​the tibial plateau to the most proximal lateral area (while excluding the osteophytes on the surface of the tibial plateau). The junction of these two lines is the MPTA.

[0107] Joint Line Convergence Angle (JLCA) - The JLCA is defined as the angle between the tangent to the most distal portion of the medial and lateral femoral condyles and the subchondral plate of the tibial plateau. Two lines are measured, one connecting the distal femoral articular surfaces and the second connecting the proximal tibial articular surfaces. The line subtended between these lines is the JLCA.

[0108] Distal Lateral Tibial Angle (LDTA) - The LDTA is measured by the angle made by a line on the central axis of the tibia (line B) and a line drawn across the distal tibia articular surface.

[0109] Tibiotalar Angle (TTA) - The tibiotalar angle is the midpoint of the medial and lateral edges of the tibial shaft (using two balls at 5cm and 15cm above the ankle). Draw a separate line along the top of the articular surface of the talus. The medial angle produces the tibiotalar angle.

[0110] The limb functional axis relative to the tibial articular surface (MALTA) is a line subtended between the limb functional axis (MAL) and a line drawn along the top of the talus articular surface (Bernasconi 2021).

[0111] With reference to Figures 28 and 29, a transverse (axial) slice is selected that best illustrates both the femoral head and the position of the femoral neck (shaft). The user (or computer program) locates the central shaft of the femur by moving up and down the leg. Then, using the axial slice through the femoral head, a line is drawn from the center of the femoral shaft to the center of the femoral head. A second line is drawn along the horizontal axis. The angle subtended between these lines is the femoral neck rotation. When the femoral head is anterior to the horizontal (towards the front of the body), the number is positive, indicating anteversion (which is counterclockwise on the right hip and clockwise on the left hip). If the femoral head is behind the horizontal, the number is negative, which is called retroversion.

[0112] With reference to Figures 30 and 31, the next axial scan to be examined is at the knee, in the center of the femoral condyles. A line is drawn along the posterior condyles of the femur and a second line is drawn along the horizontal axis. The angle subtended between these lines is the rotation of the distal femur. When the kneecap is pointing inward (clockwise on the right knee), the femur is internally rotated. This angle is positive. Similarly, on the left knee, the patella should be pointing forward, but if it is pointing inward (counterclockwise), the distal femur is internally rotated and this number is positive. If the kneecap (patella) is pointing outward, the number is inverted and negative.

[0113] To calculate hip twist, the femoral neck angle and the distal femoral angle are added together. In the example illustrated in Figure 21, on the right side (shown on the left hand side of the page), these angles are 7 degrees and 16 degrees, resulting in a right femoral anteversion of 23 degrees. On the left side, the angles are 21 degrees of distal femoral internal rotation and 6 degrees of femoral neck anterior rotation, resulting in a total femoral twist angle of 27 degrees of anteversion.

[0114] 32 and 33, the axial slice is then moved down to the proximal tibia and a line is drawn across the back of the tibial condyle and a second line is drawn to the horizontal (this approximates the same rotation as the femur). The angle subtended by these two lines is the rotation of the proximal tibia.

[0115] 34 and 35, an axial slice is then taken down to the ankle approximately 2 mm above the ankle and a line is drawn bisecting the medial and lateral malleolus. This is recorded as the medial-lateral malleolus axis. A second line is drawn relative to the horizontal and the angle subtended between them is the medial-lateral malleolus axis. As above, external rotation is expressed as a positive angle and internal relative to the midline is expressed as a negative angle (positive is counterclockwise on the right versus clockwise on the left).

[0116] 36, to calculate tibial torsion (or tibial twist), the proximal tibia measurement is added to the medial and lateral malleolus measurements. So, in the above example, 16 degrees of knee internal rotation is added to 16 degrees of ankle external rotation to produce a tibial torsion of 32 degrees for the right tibia. On the left tibia, the proximal tibia is internally rotated 32 degrees and the ankle is externally rotated 11 degrees, producing a tibial torsion of 33 degrees.

[0117] The system also provides the clinician with an exemplary overview of the lower limb alignment by presenting all of the axial measurements superimposed on top of each other, as shown in FIG. 22, thereby allowing the user to see the relationship of the foot to the hip joint.

[0118] Referring again to FIG. 6, the system also captures leg length (resolved into the height of the lateral lip of the acetabulum to the floor, the height of the central femoral head to the floor, including the absolute femoral length and the absolute tibia length). In some embodiments, there may be angulation of the bones relative to each other, in addition to rotation in the transverse (axial) plane. In such cases, there may be no bone loss, but there may be genu valgum or genu varum on one side, or flat feet, resulting in the appearance of leg length discrepancy. Leg length discrepancy may lead to pelvic obliquity, which is measured by measuring the top part of both iliac crests to the floor. This is illustrated at least in FIGS. 24-26.

[0119] In some embodiments, the processor may generate the lower limb alignment measurements either semi-automatically or automatically, as described below. For example, in a semi-automatic embodiment, the method may include loading a dataset into memory. The dataset can be either a single volume containing voxels from the pelvis to one or both feet, or it can consist of separate volumes containing the pelvis, knees, and feet individually, sorted in the patient's length direction. In some embodiments, the dataset may contain only one leg, or preferably both legs, i.e., a bilateral scan. With reference to FIG. 27, the dataset may be calibrated to ensure that it is correctly oriented, i.e., displaying axial slices with no rotation (due to patient positioning). For example, one landmark for assessing correct rotation would be the pelvic bone structure.

[0120] The method involves marking 12 locations within the three-dimensional data set, six on each side of the patient, for example, two locations are marked at the hip joint (locations indexed at the crosshairs as seen in Figures 28 and 29), two locations are marked at the knee (locations indexed at the crosshairs as seen in Figures 30 and 31), and two locations are marked at the lower tibia (locations indexed at the crosshairs as seen in Figures 32 and 33).

[0121] The method further includes calculating the hip joint angle between a line connecting the points marked in Figures 28 and 29 and a horizontal baseline. This is illustrated in Figure 34.

[0122] The method further includes calculating the knee angle between a line connecting the points marked in Figures 30 and 31 and a horizontal baseline. This is illustrated in Figure 35.

[0123] The method further includes calculating the tibial inferior angle between a line connecting the points marked in Figures 32 and 33 and a horizontal baseline. This is illustrated in Figure 36.

[0124] The method further includes displaying and comparing the hip angle / knee angle / inferior tibia angle.

[0125] In a fully automated method, many steps are similar to those described with respect to Figures 27-36, and all 12 positions discussed are determined from an AI-based algorithm with no user interaction requirements other than loading the data set where it can be processed by a processor via an algorithm. The output is formatted into quantitative results and visual graphics that are displayed in an interactive user interface. [example] [Example 1]

[0126] A method for determining axial alignment of a lower extremity is provided, the method including: determining a three-dimensional volume based on a scan of a patient's lower extremity, determining a level of hip torsion by reference to a first axis of symmetry of a femoral neck and a second axis of symmetry of a distal part of the femur, the hip torsion level being defined by an angle between the first axis of symmetry and the second axis of symmetry, determining a level of tibial torsion by reference to a third axis of symmetry of a proximal part of the tibia and a fourth axis of symmetry of a distal part of the tibia, the tibial torsion level being defined by an angle between the third axis of symmetry and the fourth axis of symmetry, and providing the level of hip torsion and the level of tibial torsion to a user.

[0127] The method involves determining the axis of symmetry by reference to the two- or three-dimensional shape of the bone (either as shown in an image of the scan, or as shown in a three-dimensional model of the scan).

[0128] The method involves locating the axis of symmetry by reference to a reference point on the bone (either located in an image of the scan or located in a three-dimensional model of the scan).

[0129] The method includes providing a first line generally representing an axis of the femoral neck, the first line generally coinciding with the first axis of symmetry, and a second line generally representing an axis of rotation of the distal portion of the fibula, the second line generally corresponding to the second axis of symmetry, and optionally further including providing a third line generally representing an axis of rotation of the proximal portion of the tibia, the third line generally corresponding to the third axis of symmetry, and a fourth line generally representing an axis of rotation of the distal portion of the tibia, the fourth line generally corresponding to the fourth axis of symmetry.

[0130] The method includes calculating an angle between the first line and the second line, and calculating an angle between the third line and the fourth line. [Example 2]

[0131] A method for determining axial alignment of a lower extremity includes determining a three-dimensional volume based on a scan of a patient's lower extremity; determining a level of hip twist by referencing a first plurality of reference points in the three-dimensional volume associated with a femoral neck and a second plurality of reference points in the three-dimensional volume associated with a distal portion of the femur, wherein the level of hip twist is defined by a relationship between the first and second plurality of reference points; determining a level of tibial twist by referencing a third plurality of reference points in the three-dimensional volume associated with a proximal portion of the tibia and a fourth plurality of reference points in the three-dimensional volume associated with a distal portion of the tibia, wherein the level of tibial twist is defined by a relationship between the third and fourth plurality of reference points; and providing the level of hip twist and the level of tibial twist to a user.

[0132] The method includes providing a first line generally representing an axis of the femoral neck, the first line generally coinciding with the first plurality of reference points, a second line generally representing an axis of rotation of the distal portion of the fibula, the second line generally corresponding to the second plurality of reference points, and providing a third line generally representing an axis of rotation of the proximal portion of the tibia, the third line generally corresponding to the third plurality of reference points, and a fourth line generally representing an axis of rotation of the distal portion of the tibia, the fourth line generally corresponding to the fourth plurality of reference points.

[0133] The method includes calculating an angle between the first line and the second line, and calculating an angle between the third line and the fourth line.

[0134] The method includes determining a femoral neck angle based on a position of a center of the femoral head relative to a center of the base of the femoral neck, wherein the first line is defined to extend between the center of the femoral head and the center of the base of the femoral neck.

[0135] The method includes determining the locations of the center of the femoral head and the center of the base of the femoral neck in three dimensional space by determining the center of the femoral head on at least two images, each of which is in a different plane, and by determining the base of the femoral neck on at least two images, each of which is in a different plane.

[0136] The method includes identifying a distal femoral angle associated with an axis of rotation of a distal end of the femur, the second line associated with the distal femoral angle.

[0137] The method includes the femoral distal angle being based on a position of the medial femoral condyle or posterior position of the medial epicondyle relative to a posterior position of the lateral femoral condyle or lateral epicondyle, respectively, and the posterior position of the medial femoral condyle or posterior position of the lateral femoral condyle or lateral epicondyle are determined in three dimensional space by determining the posterior position of the medial femoral condyle or posterior position of the medial femoral condyle on at least two images, each of which is in a different plane, and by determining the posterior position of the lateral femoral condyle or posterior position of the medial femoral condyle on at least two images, each of which is in a different plane.

[0138] The method includes determining a proximal tibial angle associated with an axis of rotation of the proximal end of the tibia, the third line associated with the proximal tibial angle.

[0139] The method includes the proximal tibial angle being based on a position of an anterior position of the medial tibial condyle relative to an anterior position of the lateral tibial condyle, the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle being determined in three dimensional space by determining the anterior position of the medial tibial condyle on at least two images, each of which is in a different plane, and by determining the anterior position of the lateral tibial condyle on at least two images, each of which is in a different plane.

[0140] The method includes determining a distal tibial angle associated with a line connecting centers of a first tangent extending between the lateral most lateral surfaces of the medial malleolus and a second tangent extending between the medial most medial surfaces of the lateral malleolus, and a fourth line associated with a line between the first tangent and the second tangent.

[0141] The method includes determining a posterior position on the lateral most lateral surface of the medial malleolus in three of the received images, an anterior position on the lateral most lateral surface of the medial malleolus in at least two of the received images, each of the images being in a different plane, a posterior position on the medial most medial surface of the lateral malleolus in at least two of the received images, each of the images being in a different plane, and an anterior position on the medial most lateral surface of the medial malleolus in three of the received images.

[0142] The method includes comparing the relationship between the first line and the second line within a single plane.

[0143] The method includes the scan being a single scan of the entire lower extremity.

[0144] The method includes the scan being taken while the patient is weight bearing.

[0145] The method includes providing a relationship of the patient's levels of hip and tibial torsion to predetermined levels of hip and tibial torsion.

[0146] The method includes displaying the alignment of the lower extremities to a user, the alignment being displayed by superimposing the second line, the third line, and the fourth line on the first line. [Example 3]

[0147] A method for determining axial alignment of a lower extremity includes determining a three-dimensional volume based on a scan of a patient's lower extremity; determining a level of hip twist by referencing a first plurality of reference points in the three-dimensional volume associated with a femoral neck and a second plurality of reference points in the three-dimensional volume associated with a distal portion of the femur, wherein the level of hip twist is defined by a relationship between the first and second plurality of reference points; determining a level of tibial twist by referencing a third plurality of reference points in the three-dimensional volume associated with a proximal portion of the tibia and a fourth plurality of reference points in the three-dimensional volume associated with a distal portion of the tibia, wherein the level of tibial twist is defined by a relationship between the third and fourth plurality of reference points; and providing the level of hip twist and the level of tibial twist to a user.

[0148] The method includes providing a first line generally representing an axis of the femoral neck, the first line generally coinciding with the first plurality of reference points, a second line generally representing an axis of rotation of the distal portion of the fibula, the second line generally corresponding to the second plurality of reference points, and providing a third line generally representing an axis of rotation of the proximal portion of the tibia, the third line generally corresponding to the third plurality of reference points, and a fourth line generally representing an axis of rotation of the distal portion of the tibia, the fourth line generally corresponding to the fourth plurality of reference points.

[0149] The method includes calculating an angle between the first line and the second line, and calculating an angle between the third line and the fourth line.

[0150] The method includes determining a femoral neck angle based on a position of a center of the femoral head relative to a center of the base of the femoral neck, wherein the first line is defined to extend between the center of the femoral head and the center of the base of the femoral neck.

[0151] The method includes locating the locations of the center of the femoral head and the center of the base of the femoral neck in three dimensional space by locating the center of the femoral head on a first image in the coronal plane, on a second image in the sagittal plane, and on a third image in the transverse plane, and by locating the center of the base of the femoral neck on a fourth image in the coronal plane, on a fifth image in the sagittal plane, and on a sixth image in the transverse plane.

[0152] The method includes identifying a distal femoral angle associated with an axis of rotation of a distal end of the femur, the second line associated with the distal femoral angle.

[0153] The method includes the femoral distal angle being based on a position of a medial femoral condyle or posterior position of the medial epicondyle relative to a posterior position of the lateral femoral condyle or lateral epicondyle, respectively, and the posterior position of the medial femoral condyle or posterior position of the medial femoral condyle and the posterior position of the lateral femoral condyle or lateral epicondyle are determined in three dimensional space by determining the posterior position of the medial femoral condyle or posterior position of the medial femoral condyle on a seventh image in the coronal plane, an eighth image in the sagittal plane, and a ninth image in the transverse plane, and by determining the posterior position of the lateral femoral condyle or posterior position of the medial femoral condyle on a tenth image in the coronal plane, an eleventh image in the sagittal plane, and a twelfth image in the transverse plane.

[0154] The method includes identifying a proximal tibial angle associated with an axis of rotation of the proximal end of the tibia, the third line associated with the proximal tibial angle.

[0155] The method includes the proximal tibial angle being based on a position of an anterior position of the medial tibial condyle relative to an anterior position of the lateral tibial condyle, and the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle are determined in three dimensional space by determining the anterior position of the medial tibial condyle on a thirteenth image in the coronal plane, on a fourteenth image in the sagittal plane, and on a fifteenth image in the transverse plane, and by determining the anterior position of the lateral tibial condyle on a sixteenth image in the coronal plane, on a seventeenth image in the sagittal plane, and on an eighteenth image in the transverse plane.

[0156] The method includes determining a distal tibial angle associated with a line connecting centers of a first tangent extending between the lateral most lateral surfaces of the medial malleolus and a second tangent extending between the medial most medial surfaces of the lateral malleolus, and a fourth line associated with a line between the first tangent and the second tangent.

[0157] The method includes determining a posterior position on the lateral most lateral surface of the medial malleolus in three of the received images, an anterior position on the lateral most lateral surface of the medial malleolus in at least two of the received images, each of the images being in a different plane, a posterior position on the medial most medial surface of the lateral malleolus in at least two of the received images, each of the images being in a different plane, and an anterior position on the medial most lateral surface of the medial malleolus in three of the received images.

[0158] The method includes comparing the relationship between the first line and the second line within a single plane.

[0159] The method includes the scan being a single scan of the entire lower extremity.

[0160] The method includes the scan being taken while the patient is weight bearing.

[0161] The method includes providing a relationship of the patient's levels of hip and tibial torsion to predetermined levels of hip and tibial torsion.

[0162] The method includes displaying an alignment of the lower extremity to a user, the alignment being displayed by superimposing the second line, the third line, and the fourth line on the first line. [Example 4]

[0163] A method for determining axial alignment of a lower extremity includes determining a three-dimensional volume based on a scan of a patient's lower extremity; determining a level of hip twist by referencing a first plurality of reference points in the three-dimensional volume associated with a femoral neck and a second plurality of reference points in the three-dimensional volume associated with a distal portion of the femur, wherein the hip twist level is defined by a relationship between the first and second plurality of reference points; determining a level of tibial twist by referencing a third plurality of reference points in the three-dimensional volume associated with a proximal portion of the tibia and a fourth plurality of reference points in the three-dimensional volume associated with a distal portion of the tibia, wherein the tibial twist level is defined by a relationship between the third and fourth plurality of reference points; and providing the level of hip twist and the level of tibial twist to a user.

[0164] The method includes providing a first line generally representing an axis of the femoral neck, the first line generally coinciding with the first plurality of reference points, a second line generally representing an axis of rotation of the distal portion of the fibula, the second line generally corresponding to the second plurality of reference points, a third line generally representing an axis of rotation of the proximal portion of the tibia, the third line generally corresponding to the third plurality of reference points, and a fourth line generally representing an axis of rotation of the distal portion of the tibia, the fourth line generally corresponding to the fourth plurality of reference points.

[0165] The method includes calculating an angle between the first line and the second line, and calculating an angle between the third line and the fourth line.

[0166] The method includes determining a femoral neck angle based on a position of a center of the femoral head relative to a center of the base of the femoral neck, wherein the first line is defined to extend between the center of the femoral head and the center of the base of the femoral neck.

[0167] The method includes determining a location of a center of the femoral head and a location of a center of the base of the femoral neck in three dimensional space by determining the center of the femoral head and the center of the base of the femoral neck within a three dimensional model based on the scan of the patient's lower leg.

[0168] The method includes identifying a distal femoral angle associated with an axis of rotation of a distal end of the femur, the second line associated with the distal femoral angle.

[0169] The method includes the femoral distal angle being based on a position of the medial femoral condyle or posterior position of the medial epicondyle relative to a posterior position of the lateral femoral condyle or lateral epicondyle, respectively, and the positions of the medial femoral condyle or posterior position of the medial epicondyle and the lateral femoral condyle or posterior position of the lateral epicondyle are determined in three dimensional space by determining the posterior position of the medial femoral condyle or posterior position of the medial epicondyle and the lateral femoral condyle or posterior position of the lateral epicondyle within a three dimensional model based on the scan of the lower leg of the patient.

[0170] The method includes identifying a proximal tibial angle associated with an axis of rotation of the proximal end of the tibia, the third line associated with the proximal tibial angle.

[0171] The method includes the proximal tibial angle being based on a position of an anterior position of the medial tibial condyle relative to an anterior position of the lateral tibial condyle, the positions of the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle being determined in three dimensional space by determining the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle within a three dimensional model based on the scan of the patient's lower leg.

[0172] The method includes determining a distal tibial angle associated with a line connecting centers of a first tangent extending between the lateral most lateral surfaces of the medial malleolus and a second tangent extending between the medial most medial surfaces of the lateral malleolus, and a fourth line associated with a line between the first tangent and the second tangent.

[0173] The method includes determining in three dimensional space a posterior location on the lateral most lateral surface of the medial malleolus and an anterior location on the lateral most lateral surface of the medial malleolus by determining the posterior location on the lateral most lateral surface of the medial malleolus and the anterior location on the lateral most lateral surface of the medial malleolus based on the scan of the lower extremity of the patient by determining within a three dimensional model.

[0174] The method includes comparing the relationship between the first line and the second line within a single plane.

[0175] The method includes the scan being a single scan of the entire lower extremity.

[0176] The method includes the scan being taken while the patient is weight bearing.

[0177] The method includes providing a relationship of the patient's levels of hip and tibial torsion to predetermined levels of hip and tibial torsion.

[0178] The method includes displaying an alignment of the lower extremity to a user, the alignment being displayed by superimposing the second line, the third line, and the fourth line on the first line. [Example 5]

[0179] A method for determining axial alignment of the lower extremity includes positioning a patient, scanning the patient's lower extremity to generate images including cross-sections in a frontal plane, a sagittal plane, and a transverse plane, obtaining a level of hip torsion based on the images, and obtaining a level of tibial torsion based on the images, wherein the level of hip torsion and the level of tibial torsion are mapped in three-dimensional space.

[0180] The method includes aligning the image by viewing the image in the transverse plane through the patient's pelvis and at the level of the anterior iliac spine of the iliac crest, and aligning includes rotating the image in the transverse plane for symmetry.

[0181] The method includes determining a femoral neck angle based on a position of a center of the femoral head relative to a center of the base of the femoral neck, wherein the positions of the center of the femoral head and the center of the base of the femoral neck are determined in three dimensional space in a first set of three images and a second set of three images, respectively, each of the first set of three images and the second set of three images including images in the coronal plane, the sagittal plane, and the transverse plane.

[0182] The method includes determining a femoral distal angle based on a position of a medial femoral condyle or a posterior position of the medial epicondyle relative to a posterior position of a lateral femoral condyle or a posterior position of the lateral epicondyle, respectively, wherein the posterior position of the medial femoral condyle or the posterior position of the lateral femoral condyle or the posterior position of the lateral epicondyle are determined in three dimensional space in a third set of three images and a fourth set of three images, respectively, each of the third set of three images and the fourth set of three images including images in the coronal plane, the sagittal plane, and the transverse plane.

[0183] The method includes determining a proximal tibial angle relative to an axis of rotation of the proximal end of the tibia, the proximal tibial angle being based on a position of an anterior position of the medial tibial condyle relative to an anterior position of the lateral tibial condyle, the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle being determined in three dimensional space in a fifth set of three images and a sixth set of three images, respectively, the first set of three images and the second set of three images each including images in the coronal plane, the sagittal plane, and the transverse plane.

[0184] The method includes determining a distal tibial angle associated with a line connecting the centers of a first tangent line extending between the outermost lateral surface of the medial malleolus and a second tangent line extending between the innermost medial surface of the lateral malleolus.

[0185] The method includes determining in three dimensional space a posterior location on the lateral most lateral surface of the medial malleolus, an anterior location on the lateral most lateral surface of the medial malleolus, a posterior location on the medial most medial surface of the lateral malleolus, and an anterior location on the medial most lateral surface of the medial malleolus, respectively, in a seventh set of three images, an eighth set of three images, a ninth set of three images, and a tenth set of three images, each of the seventh set of three images through the tenth set of three images including images in the coronal plane, the sagittal plane, and the transverse plane. [Example 6]

[0186] 1. A computer-implemented method for providing hip and tibial torsion values, the method comprising: receiving a plurality of images from a three-dimensional scan of at least one lower extremity of a patient, the images including a plurality of three-image sets, the three-image sets including an image in a coronal plane, an image in a sagittal plane, and an image in a transverse plane; identifying a femoral neck axis by identifying a center of the femoral head on a first set of three images and a center of a base of the femoral neck on a second set of three images; identifying a distal femoral axis of a patient's femur associated with an axis of rotation at a distal end of the femur, the distal femoral axis being determined in a third set of three images and a fourth set of three images; and identifying an angle between the femoral neck axis and the distal femoral axis, the angle between the femoral neck axis and the distal femoral axis. identifying a proximal tibia axis associated with an axis of rotation of the patient's tibia at a proximal end of the tibia, the proximal tibia axis being determined in a fifth set of three images and a sixth set of three images; identifying a distal tibia axis associated with an axis of rotation of the patient's tibia at a distal end of the tibia, the proximal tibia axis being determined in a seventh set of three images, an eighth set of three images, a ninth set of three images, and a tenth set of three images; identifying an angle between the proximal tibia axis and the distal tibia axis, a neck axis and the distal femoral axis, the angle between the femoral neck axis and the distal femoral axis being indicative of tibial torsion.

[0187] The computer-implemented method includes providing a shape over the first set of three images and the second set of three images, the shape representing a three-dimensional shape.

[0188] The computer-implemented method includes sizing the shape to a maximum size that can be positioned within the base of the femoral neck such that the shape is shown in at least two images of the second set of three images to be in contact with the cortex of the base of the femoral neck.

[0189] The computer-implemented method includes finding a center of mass of the femoral head and a center of mass of the base of the femoral neck.

[0190] The computer-implemented method includes identifying and selecting the center of the femoral head and the center of the base of the femoral neck on the first set of three images and the second set of three images, the first set of three images and the second set of three images being selected from a plurality of sets of three images.

[0191] The computer-implemented method includes locating the center of the femoral head, locating the center of the base of the femoral neck, locating the distal axis of the femur, locating the proximal axis of the tibia, and locating the distal axis of the tibia, accomplished by a computer system, with software programmed to perform the identification based on prior training on multiple samples.

[0192] The description and illustrations of one or more aspects provided in this application are not intended to limit or restrict in any manner the scope of the disclosure as claimed. The aspects, examples, and details provided in this application are believed to be sufficient to transfer ownership and enable others to make and use the best mode of the claimed disclosure. The claimed disclosure should not be construed as being limited to any aspect, example, or detail provided in this application. Various features (both structural and methodological), whether shown and described in combination or separately, are intended to be selectively included or omitted to produce an embodiment having a particular set of features. Those skilled in the art may, given the description and illustrations provided herein, conceive modifications, variations, and alternative aspects that fall within the spirit of the broader aspects of the general inventive concept embodied in this application without departing from the broader scope of the claimed disclosure.

[0193] Within the context of describing this invention (particularly in the context of the claims which follow), the use of the terms "a," "an," and "the," and similar referents, should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended (i.e., meaning "including, but not limited to"), unless otherwise noted. The term "connected" should be construed as being partially or wholly contained within, attached to, or joined together, even if there is something intervening.

[0194] Recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within that range, unless otherwise stated herein, and each separate value is incorporated into the specification as if it were individually set forth herein.

[0195] The use of directions such as front, rear, top and bottom, upper and lower, etc., refers to the embodiment shown in the drawings and therefore should not be taken as limiting. A reversal or rotation of the embodiment in the drawings will, of course, result in a consistent reversal or rotation of the terminology.

[0196] As will be apparent to those skilled in the art, various modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention. There is no intention to limit the present invention to one or more specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents that fall within the spirit and scope of the present invention as defined in the appended claims. Thus, it is intended that the present invention cover modifications and variations of the present invention, provided that they fall within the scope of the appended claims and their equivalents.

[0197] One or more systems described herein may be implemented on one or more computers in any form, and the algorithms and programs may be implemented as dedicated applications or in client-server architectures, including web-based architectures, and may include functional programs, codes, and code segments. The computer system of the present invention may include software programs that may be stored on a computer and / or storage device (e.g., medium) and / or executed over a network. The computer steps may be implemented through program code or program modules stored on a storage medium.

[0198] It is contemplated that any of the methods and / or systems may include providing output to a display, such as a computer display. The output may include graphics, such as one or more of lines, that may be displayed in relation to (i) a 3D model of the lower leg, (ii) other lines, and / or (iii) predefined reference data, such as data representing baseline hip or tibial torsion. The methods and systems may also allow a user to manipulate the 3D model to visualize the lines in different orientations. The methods and systems may also provide associated metrics, such as angles, percentages, and anatomical conditions, associated with hip flexion and tibial torsion identified via the methods and systems described herein.

[0199] The computer processes herein may be described in terms of various processing steps. Such processing steps may be realized by any number of hardware and / or software components that perform the specified functions. For example, the described embodiments may employ various integrated circuit components, such as memory elements, processing elements, logic elements, look-up tables, etc., which may perform a wide variety of functions under the control of one or more microprocessors or other control devices. Similarly, where elements of the described embodiments are implemented using software programming or elements, the invention may be implemented using any programming or scripting language, such as C, C++, Java, or assembler, and the various algorithms are implemented using any combination of data structures, objects, processes, routines, or other programming elements. Functional aspects may be implemented in algorithms that run on one or more processors. Additionally, embodiments of the invention may employ any number of conventional techniques for electronics configuration, signal processing and / or signal control, data processing, and the like. The terms "mechanism" and "element" are used broadly and are not limited to mechanical or physical embodiments, but rather may include software routines and the like in conjunction with processors.

[0200] The specific implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any manner. For purposes of brevity, conventional electronics, control systems, software development, and other functional aspects of the system (and components of the individual operating components of the system) may not be described in detail.

[0201] Any of the methods and examples provided herein may, where applicable, be implemented on a computing device that includes one or more processors and memory storing instructions that, when executed by the one or more processors, cause the one or more processors to perform the methods as described herein.

[0202] Any of the methods and examples provided herein may be stored on a temporary or non-transitory computer-readable medium storing instructions for providing hip and tibial torsion values, as applicable, that, when executed by one or more processors of a computing device, cause the computing device to perform the methods as described herein.

[0203] Finally, the steps of any method described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better elucidate the invention and does not impose limitations on the scope of the invention unless specifically claimed. Numerous modifications and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention.

[0204] The invention of this application has been described above both generically and with respect to specific embodiments. As will be apparent to those skilled in the art, various modifications and variations can be made in these embodiments without departing from the scope of this disclosure. Therefore, it is intended that these embodiments cover the modifications and variations of this invention, provided that they fall within the scope of the appended claims and their equivalents.

Claims

1. 1. A method for determining axial alignment of a lower extremity, comprising: identifying a three-dimensional volume based on a scan of the patient's lower extremity; determining a level of hip twist by referencing a first axis of symmetry of the femoral neck and a second axis of symmetry of the distal portion of the femur, wherein the hip twist is defined by the angle between the first axis of symmetry and the second axis of symmetry; determining a level of tibial torsion by referencing a third axis of symmetry of the proximal portion of the tibia and a fourth axis of symmetry of the distal portion of the tibia, wherein the tibial torsion is defined by the angle between the third axis of symmetry and the fourth axis of symmetry; providing the level of hip torsion and the level of tibial torsion to a user; A method comprising:

2. The method described in claim 1, comprising determining the first to fourth axes of symmetry by referencing the two-dimensional or three-dimensional shape of the lower limb in images from the scan.

3. The method of claim 1, comprising determining the first to fourth axes of symmetry by referencing reference points on the lower limb in images from the scan.

4. 4. The method of claim 1, comprising comparing the angle between the first axis of symmetry and the second axis of symmetry in a single plane.

5. 4. The method of claim 1, wherein the scan is a single scan of the entire lower limb.

6. 4. The method of claim 1, wherein the scan is taken while the patient is weight-bearing.

7. A method described in any one of claims 1 to 3, further comprising providing a relationship of the patient's level of hip torsion and tibial torsion to a predetermined level of the hip torsion and tibial torsion.

8. 4. The method of claim 1, further comprising displaying the alignment of the lower limb to a user, the alignment being displayed by superimposing the second axis of symmetry, the third axis of symmetry, and the fourth axis of symmetry on the first axis of symmetry.

9. 1. A method for determining axial alignment of a lower extremity, comprising: positioning the patient; scanning the patient's lower extremity to generate images including cross-sections in a coronal plane, a sagittal plane, and a transverse plane; obtaining a level of hip joint torsion based on the image; obtaining a level of tibial torsion based on the image; Including, The method wherein the levels of hip torsion and the levels of tibial torsion are mapped in three-dimensional space.

10. 10. The method of claim 9, further comprising aligning the images by viewing the images in the transverse plane through the patient's pelvis at the level of the anterior iliac spine of the iliac crest, wherein the aligning the images comprises rotating the images in the transverse plane for symmetry.

11. 11. The method of claim 9 or 10, wherein obtaining the level of hip torsion includes determining a femoral neck angle based on a position of a center of the femoral head relative to a center of a base of the femoral neck, wherein the position of the center of the femoral head and the position of the center of the base of the femoral neck are determined in three-dimensional space in a first image set and a second image set, respectively, and each of the first image set and the second image set includes images in the coronal plane, the sagittal plane, and the transverse plane.

12. 11. The method of claim 9 or 10, wherein obtaining the level of hip torsion further comprises determining a distal femoral angle based on a position of the medial femoral condyle or posterior position of the medial femoral epicondyle relative to a posterior position of the lateral femoral condyle or lateral epicondyle, respectively, wherein the posterior position of the medial femoral condyle or the posterior position of the lateral femoral condyle or the posterior position of the lateral femoral epicondyle are determined in three-dimensional space in a third image set and a fourth image set, respectively, and each of the third image set and the fourth image set includes images in the coronal plane, the sagittal plane, and the transverse plane.

13. 11. The method of claim 9 or 10, wherein obtaining the level of tibial torsion includes determining a proximal tibial angle relative to an axis of rotation of the proximal end of the tibia, the proximal tibial angle being based on a position of an anterior position of a medial tibial condyle relative to an anterior position of a lateral tibial condyle, the anterior position of the medial tibial condyle and the anterior position of the lateral tibial condyle being determined in three-dimensional space in fifth and sixth image sets, respectively, the fifth and sixth image sets each including images in the coronal, sagittal, and transverse planes.

14. 14. The method of claim 13, wherein obtaining the level of tibial torsion includes identifying a distal tibial angle associated with a line connecting centers of a first tangent line extending between the outermost lateral surfaces of the medial malleolus and a second tangent line extending between the innermost medial surfaces of the lateral malleolus.

15. 15. The method of claim 14, wherein determining tibial torsion comprises determining in three-dimensional space a posterior position on the lateral-most surface of the medial malleolus, an anterior position on the lateral-most surface of the medial malleolus, a posterior position on the medial-most surface of the lateral malleolus, and an anterior position on the medial-most surface of the medial malleolus in seventh, eighth, ninth, and tenth image sets, respectively, wherein each of the seventh through tenth image sets includes images in the coronal, sagittal, and transverse planes.

16. 1. A computer-implemented method for providing hip and tibial torsion values, comprising: receiving a plurality of images from a three-dimensional scan of at least one lower extremity of a patient, the images including a plurality of image sets, each of the image sets including an image in a coronal plane, an image in a sagittal plane, and an image in a transverse plane; Identifying the femoral neck axis by identifying the center of the femoral head on the first set of images and the center of the base of the femoral neck on the second set of images; identifying a distal femoral axis of the patient's femur associated with an axis of rotation at a distal end of the femur, the distal femoral axis being determined in a third set of images and a fourth set of images; determining an angle between the femoral neck axis and the distal femoral axis, the angle between the femoral neck axis and the distal femoral axis representing hip torsion; identifying a proximal tibial axis of the patient's tibia associated with an axis of rotation at a proximal end of the tibia, the proximal tibial axis being determined in a fifth image set and a sixth image set; identifying a distal tibial axis of the patient's tibia associated with an axis of rotation at a distal end of the tibia, the distal tibial axis being determined in a seventh image set, an eighth image set, a ninth image set, and a tenth image set; determining an angle between the proximal tibia axis and the distal tibia axis or the medial / lateral malleolar axis, wherein the angle between the proximal tibia axis and the distal tibia axis or the medial / lateral malleolar axis represents tibial torsion; 11. A computer-implemented method comprising:

17. 17. The computer-implemented method of claim 16, wherein identifying the femoral neck axis comprises providing a predetermined shape on the first set of images and the second set of images, the predetermined shape representing a three-dimensional shape.

18. 18. The computer-implemented method of claim 17, wherein identifying the femoral neck axis comprises sizing the predetermined shape to a maximum size that can be positioned within the base of the femoral neck such that the predetermined shape is shown in contact with the cortex of the base of the femoral neck in at least two images of the second image set.

19. 19. The computer-implemented method of claim 16, wherein identifying the femoral neck axis comprises finding the center of mass of the femoral head and the center of mass of the base of the femoral neck.

20. 19. The computer-implemented method of claim 16, wherein identifying the femoral neck axis comprises identifying and selecting the center of the femoral head and the center of the base of the femoral neck on the first image set and the second image set, the first image set and the second image set being selected from a plurality of image sets.

21. 19. The computer-implemented method of claim 16, wherein identifying the center of the femoral head, identifying the center of the base of the femoral neck, identifying the distal axis of the femur, identifying the proximal axis of the tibia, and identifying the distal axis of the tibia are accomplished by a computer system including a software module, the software module being programmed to perform the identification based on prior training on multiple samples.

22. 1. A computing device for providing hip and tibial torsion values, comprising: one or more processors; a memory storing instructions that, when executed by the one or more processors, cause the one or more processors to: identifying a three-dimensional volume based on a scan of the patient's lower extremity; determining a level of hip twist by referencing a first axis of symmetry of the femoral neck and a second axis of symmetry of the distal portion of the femur, the hip twist being defined by the angle between the first axis of symmetry and the second axis of symmetry; determining a level of tibial torsion by referencing a third axis of symmetry of the proximal portion of the tibia and a fourth axis of symmetry of the distal portion of the tibia, wherein the tibial torsion is defined by the angle between the third axis of symmetry and the fourth axis of symmetry; providing the level of hip torsion and the level of tibial torsion to a user; a memory for performing the A computing device comprising:

23. A computing device as described in claim 22, wherein determining the first to fourth axes of symmetry includes determining the first to fourth axes of symmetry by reference to a two-dimensional or three-dimensional shape of the lower limb in an image from the scan.

24. A computing device as described in claim 22, wherein determining the first to fourth axes of symmetry includes determining the first to fourth axes of symmetry by reference to reference points on the lower limb in images from the scan.

25. A computing device as described in any one of claims 22 to 24, wherein when the instructions are executed by the one or more processors, the one or more processors further compare the angle between the first axis of symmetry and the second axis of symmetry within a single plane.

26. 25. The computing device of any one of claims 22 to 24, wherein the scan is a single scan of the entire lower limb.

27. 25. The computing device of any one of claims 22 to 24, wherein the scan is taken while the patient is weight-bearing.

28. A computing device as described in any one of claims 22 to 24, further configured to provide a relationship of the patient's level of hip torsion and tibial torsion to a predetermined level of the hip torsion and tibial torsion.

29. 25. The computing device of claim 22, further configured to display to a user an alignment of the lower limb, the alignment being displayed by superimposing the second axis of symmetry, the third axis of symmetry, and the fourth axis of symmetry on the first axis of symmetry.

30. 1. A non-transitory computer-readable medium having stored thereon computer-readable instructions for providing hip and tibial torsion values, the computer-readable instructions, when executed by one or more processors of a computing device, causing the computing device to: identifying a three-dimensional volume based on a scan of the patient's lower extremity; determining a level of hip twist by referencing a first axis of symmetry of the femoral neck and a second axis of symmetry of the distal portion of the femur, the hip twist being defined by the angle between the first axis of symmetry and the second axis of symmetry; determining a level of tibial torsion by referencing a third axis of symmetry of the proximal portion of the tibia and a fourth axis of symmetry of the distal portion of the tibia, wherein the tibial torsion is defined by the angle between the third axis of symmetry and the fourth axis of symmetry; providing the level of hip torsion and the level of tibial torsion to a user; A non-transitory computer-readable medium for causing

31. A non-transitory computer-readable medium as described in claim 30, wherein determining the first to fourth axes of symmetry includes determining the first to fourth axes of symmetry by reference to a two-dimensional or three-dimensional shape of the lower limb in an image from the scan.

32. A non-transitory computer-readable medium as described in claim 30, wherein determining the first to fourth axes of symmetry includes determining the first to fourth axes of symmetry by reference to reference points on the lower limb in images from the scan.

33. 33. The non-transitory computer-readable medium of any one of claims 30 to 32, wherein the angles between the first and second axes of symmetry are compared within a single plane.

34. 33. The non-transitory computer-readable medium of any one of claims 30 to 32, wherein the scan is a single scan of the entire lower extremity.

35. 33. The non-transitory computer readable medium of any one of claims 30 to 32, wherein the scan is taken while the patient is weight bearing.

36. A non-transitory computer-readable medium as described in any one of claims 30 to 32, wherein the computing device is provided with access to a relationship of the patient's level of hip torsion and tibial torsion to predetermined levels of the hip torsion and tibial torsion.

37. The computer-readable instructions, when executed by the one or more processors of the computing device, 33. The non-transitory computer-readable medium of any one of claims 30 to 32, causing the computing device to display alignment of the lower extremity by superimposing the second axis of symmetry, the third axis of symmetry, and the fourth axis of symmetry on the first axis of symmetry.

Images