Distal femoral pin guide instrument and method of using the same in an orthopaedic surgical knee procedure

Abstract

An orthopaedic surgical instrument includes an alignment guide and an anterior stylus. The alignment guide is configured to contact the distal femoral condyles of a patient's femur so as to align a distal cutting block. A number of shims are selectively installed on the alignment guide based on desired extension gaps. A method of surgically preparing a patient's femur is also disclosed.

Description

DISTAL FEMORAL PIN GUIDE INSTRUMENT AND METHOD OF USING THE SAME IN AN ORTHOPAEDIC SURGICAL KNEE PROCEDURETECHNICAL FIELD

[0001] The present disclosure relates generally to orthopaedic surgical instruments and, more particularly, to surgical instruments used to resect a patient’s bone.BACKGROUND

[0002] Joint arthroplasty is a well-known surgical procedure by which a diseased and / or damaged natural joint is replaced by a prosthetic joint. For example, in a total knee arthroplasty surgical procedure, a patient’s natural knee joint is partially or totally replaced by a prosthetic knee joint or knee prosthesis. To facilitate the replacement of the natural joint with the prosthesis, orthopaedic surgeons use a variety of orthopaedic surgical instruments such as, for example, saws, drills, reamers, rasps, broaches, cutting blocks, drill guides, milling guides, and other surgical instruments.

[0003] In total knee arthroplasty (TKA), the femur and tibia of the patient’s knee are resected to create planar surfaces onto which a prosthetic femoral component and tibial component, respectively, are installed. Traditional TKA involves determining the resection planes based on a pre-determined angle as a function of mechanical alignment or by using a balanced approach that sets the resection planes based on ligament tension. More recently, kinematic alignment techniques involve determining the resection planes as a function of the native, pre-disease state of the patient’s knee.

[0004] In any of such approaches, the patient’s knee is analyzed and the desired extension gaps are determined with the patient’s knee positioned in extension. The cutting blocks may be positioned using an intramedullary rod for the femur and an extramedullary jig on the tibia with the knee in flexion.SUMMARY

[0005] According to one aspect of the disclosure, an orthopaedic surgical instrument for use in the surgical preparation of a patient’s femur during performance of an orthopaedic knee procedure includes a medial pin guide and a lateral pin guide. The medial pin guide hasan elongated guide bore that includes a longitudinal axis extending in the anterior / posterior direction. The lateral pin guide has an elongated guide bore that includes a longitudinal axis extending in the anterior / posterior direction so as to be parallel with the longitudinal axis of the elongated guide bore of the medial pin guide. The orthopaedic surgical instrument also includes a medial paddle and a lateral paddle that are spaced apart inferiorly from the medial pin guide and the lateral pin guide. The medial paddle has an alignment surface that extends parallel to the longitudinal axis of the elongated guide bore of the medial pin guide and is configured to be positioned in contact with a medial distal condyle of the patient’s femur. The lateral paddle has an alignment surface that extends parallel to the longitudinal axis of the elongated guide bore of the lateral pin guide and is configured to be positioned in contact with a lateral distal condyle of the patient’s femur. The orthopaedic surgical instrument also includes an anterior stylus extending superiorly away from the medial paddle and the lateral paddle. The anterior stylus includes an alignment surface that is configured to be positioned in contact with an anterior surface of the patient’s femur.

[0006] The anterior stylus may be configured to rotate relative to the medial paddle and the lateral paddle while remaining perpendicular to the medial pin guide and the lateral pin guide.

[0007] In an embodiment, the alignment surface of the anterior stylus extends perpendicularly to both the longitudinal axis of the elongated guide bore of the medial pin guide and the longitudinal axis of the elongated guide bore of the lateral pin guide.

[0008] The orthopaedic surgical instrument also includes a femoral platform, with both the medial paddle and the lateral paddle being formed in the femoral platform. The anterior stylus may include an inferior end secured to the platform and an opposite superior end, with the alignment surface of the anterior stylus being formed in its superior end.

[0009] In an embodiment, the femoral platform includes a pin-receiving bore positioned between the medial paddle and the lateral paddle. In such an embodiment, the anterior stylus includes a pin extending posteriorly from its inferior end, with such a pin being received into the pin-receiving bore of the femoral platform so as to removably secure the anterior stylus to the femoral platform.

[0010] The orthopaedic surgical instrument also includes a plurality of shims. Each of the plurality of shims has a thickness that is different from the thickness of at least some of the other of the plurality of shims. In one embodiment, each of the plurality of shims includes a locking mechanism that mates with a locking mechanism of the medial paddle and the lateral paddle such that each of the plurality of shims is configured to be separately coupled to boththe medial paddle and the lateral paddle. In another embodiment, each of the plurality of shims includes a locking mechanism that mates with a locking mechanism of one or both of the medial paddle and the lateral paddle such that each of the plurality of shims is configured to be separately coupled to one or both of the medial paddle and the lateral paddle.

[0011] In one embodiment, the locking mechanism of each of the plurality of shims includes an arcuate-shaped rail, and the locking mechanism of the medial paddle and the lateral paddle includes an arcuate-shaped slot configured to receive the arcuate-shaped rail of each of the plurality of shims.

[0012] In another embodiment, the locking mechanism of each of the plurality of shims includes a post, and the locking mechanism of the medial paddle and the lateral paddle includes an elongated bore configured to receive the post of each of the plurality of shims.

[0013] In another embodiment, the femoral platform of the orthopaedic surgical instrument has a medial arm and a lateral arm extending superiorly therefrom. The medial pin guide is secured to a superior end of the medial arm, and the lateral pin guide is secured to a superior end of the lateral arm.

[0014] According to another aspect, a method of surgically preparing a femur and a tibia of a knee of a patient during performance of an orthopaedic knee procedure includes determining, with the patient’s knee positioned in extension, (i) a desired medial extension gap indicative of a distance between a medial condyle of the patient’s femur and a medial plateau of the patient’s tibia, and (ii) a desired lateral extension gap indicative of a distance between a lateral condyle of the patient’s femur and a lateral plateau of the patient’s tibia. A medial shim having a thickness that corresponds to the determined medial extension gap is selected from a plurality of shims of differing thicknesses and installed onto a medial paddle of a femoral pin guide instrument. A lateral shim having a thickness that corresponds to the determined lateral extension gap is selected from a plurality of shims of differing thicknesses and installed onto a lateral paddle of the femoral pin guide instrument. With the patient’s knee positioned in flexion, the femoral pin guide instrument is positioned on a distal end of the patient’s femur such that (i) the femoral shim installed on the medial paddle of the femoral pin guide instrument contacts a medial distal femoral condyle of the patient’s femur, (ii) the femoral shim installed on the lateral paddle of the femoral pin guide instrument contacts a lateral distal femoral condyle of the patient’s femur, and (iii) an anterior stylus of the femoral pin guide instrument contacts an anterior surface of the patient’s femur. With the femoral pin guide instrument positioned on the distal end of the patient’s femur, a pair of guide pins are installed into the distal end of the patient’s femur.

[0015] The desired medial extension gap and the desired lateral extension gap may be determined by operating a ligament balancer to balance the patient’s knee.

[0016] The desired medial extension gap and the desired lateral extension gap may be determined by mechanically aligning the patient’s knee.

[0017] The desired medial extension gap and the desired lateral extension gap may be determined by determining an amount of cartilage loss within the patient’s knee.

[0018] In an embodiment, a distal cutting block is installed on the pair of guide pins subsequent to installation of the pins. A distal resection of the distal end of the patient’s knee so as to produce a planar resected surface is then performed by use of the distal cutting block.

[0019] According to another aspect, a method of surgically preparing a femur and a tibia of a knee of a patient during performance of an orthopaedic knee procedure includes determining, with the patient’s knee positioned in extension, a desired extension gap indicative of a distance between a condyle of the patient’s femur and a plateau of the patient’s tibia. A shim having a thickness based on the determined extension gap is selected from a plurality of shims of differing thicknesses and installed onto a paddle of a femoral pin guide instrument. With the patient’s knee positioned in flexion, the femoral pin guide instrument is then positioned on a distal end of the patient’s femur such that the femoral shim installed on the paddle of the femoral pin guide instrument contacts a distal femoral condyle of the patient’s femur. With the femoral pin guide instrument positioned on the distal end of the patient’s femur, a pair of guide pins are installed into the distal end of the patient’s femur.

[0020] The desired extension gap may be determined by operating a ligament balancer to balance the patient’s knee.

[0021] The desired extension gap may be determined by mechanically aligning the patient’s knee.

[0022] The desired extension gap may be determined by determining an amount of cartilage loss within the patient’s knee.

[0023] In an embodiment, a distal cutting block is installed on the pair of guide pins subsequent to installation of the pins. A distal resection of the distal end of the patient’s knee so as to produce a planar resected surface is then performed by use of the distal cutting block.

[0024] In an embodiment, the desired extension gap is a desired medial extension gap indicative of a distance between a medial condyle of the patient’s femur and a medial plateau of the patient’s tibia. In such an embodiment, the selected shim is installed onto a medial paddle of the femoral pin guide instrument so as to contact a medial distal femoral condyle of the patient’s femur.

[0025] In an embodiment, the desired extension gap is a desired lateral extension gap indicative of a distance between a lateral condyle of the patient’s femur and a lateral plateau of the patient’s tibia. In such an embodiment, the selected shim is installed onto a lateral paddle of the femoral pin guide instrument so as to contact a lateral distal femoral condyle of the patient’s femur.

[0026] In an embodiment, the selected shim has a thickness that corresponds to the determined extension gap.

[0027] The method may also include resecting a proximal end of a patient’s tibia to remove a portion of the patient’s tibia having a thickness based on the determined extension gap. In such an embodiment, a sum of the thickness of the resected portion of the patient’s tibia and the thickness of the shim corresponds to the determined extension gap.BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The detailed description particularly refers to the following figures, in which:

[0029] FIGS. 1 and 2 are perspective views of a distal femoral pin guide instrument for use in the surgical preparation of a patient’s femur during performance of an orthopaedic knee procedure;

[0030] FIG. 3 is an exploded perspective view of the distal femoral pin guide instrument of FIG. 1;

[0031] FIG. 4 is a perspective view showing the shims being assembled to the distal femoral pin guide instrument;

[0032] FIG. 5 is a frontal view of a patient’s knee prior to performance of an orthopaedic knee procedure;

[0033] FIG. 6 is a frontal view showing the distal femoral pin guide instrument installed on the distal end of the patient’s femur prior to performance of a distal resection of the patient’s femur, note the patient’s knee is shown in flexion in FIG. 6;

[0034] FIG. 7 is a side view showing the distal femoral pin guide instrument installed on the distal end of the patient’s femur prior to performance of a distal resection of the patient’s femur, note the patient’s knee is shown in flexion in FIG. 7; and

[0035] FIG. 8 is a perspective view showing a distal cutting block installed on the distal end of the patient’s femur and being used during performance of a distal resection of the patient’s femur, note the patient’s knee is shown in flexion in FIG. 8.DETAILED DESCRIPTION OF THE DRAWINGS

[0036] While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

[0037] Terms representing anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etcetera, may be used throughout the specification in reference to the orthopaedic implants and surgical instruments described herein as well as in reference to thepatient’s natural anatomy. Such terms have well-understood meanings in both the study of anatomy and the field of orthopaedics. Use of such anatomical reference terms in the written description and claims is intended to be consistent with their well -understood meanings unless noted otherwise.

[0038] Referring to FIGS. 1-4, an orthopaedic surgical instrument 10 - in the form of a distal femoral pin guide instrument - for use in the surgical preparation of a patient’s femur during performance of an orthopaedic knee procedure is shown. The distal femoral pin guide instrument 10 includes an alignment guide 12 and a removable anterior stylus 14. The distal femoral pin guide instrument 10 is used to position and install a pair of guide pins 110 (see FIGS. 6-8) in the surgical preparation of the patient’s distal femur during a knee replacement procedure. As will be discussed below in greater detail, the installed guide pins 110 are used to position a femoral distal cutting block 112 (see FIG. 8) that is used to perform a distal cut on the patient’s femur.

[0039] As can be seen in FIG. 1-4, the alignment guide 12 of the distal femoral pin guide instrument 10 includes a pair of pin guides 20, 22 configured to guide the placement of the pair of guide pins 110 into the distal end 108 of a patient’s femur 100 (see FIGS. 6 and 7). The medial pin guide 20 has an elongated guide bore 24 defined therein. The guide bore 24 of the medial pin guide 20 has a longitudinal axis 28 that extends in the anterior / posterior direction. Similarly, the lateral pin guide 22 has an elongated guide bore 26 defined therein. The guide bore 28 of the lateral pin guide 22 includes a longitudinal axis 30 that extends in the anterior / posterior direction and is parallel with the longitudinal axis 28 of the elongated guide bore 24 of the medial pin guide 20.

[0040] As can be seen in FIGS. 1-4, the alignment guide 12 includes a femoral platform 38 that has a pair of paddles 40, 42 formed therein. The pin guides 20, 22 are respectively secured to the femoral platform 38 via a pair of arms 50, 52 extending superiorly away from the platform 38. Specifically, the medial pin guide 20 is secured to the superior end of the medial arm 50, whereas the lateral pin guide 22 is secured to the superior end of the lateral arm 52. In such a way, the medial paddle 40 is spaced apart inferiorly from the medial pin guide 20. Similarly, the lateral paddle 42 is spaced apart inferiorly from the lateral pin guide 22.

[0041] As can also be seen in FIGS. 1-4, the paddles 40, 42 include alignment surfaces 44, 46, respectively, that have a fixed relationship relative to the pin guides 20, 22 such that during use of the distal femoral pin guide instrument 10 the pin guides 20, 22 are positioned in a desired location for placement of the guide pins and the paddles 40, 42 are positioned to contact the distal condyles of the patient’s femur. In the illustrative embodiment describedherein, the alignment surface 44 of the lateral paddle 42 extends parallel to the longitudinal axis 28 of the elongated guide bore 24 of the medial pin guide 20, whereas the alignment surface 46 of the lateral paddle 42 extends parallel to the longitudinal axis 30 of the elongated guide bore 26 of the lateral pin guide 22.

[0042] As alluded to above, and as will be discussed below in more detail, the alignment surface 44 of the medial paddle 40 is configured to confront or abut a medial distal condyle 102 of the patient’s femur 100. As will also be described below in greater detail, in some instances, the alignment surface 44 may also include a shim that confronts (and may be positioned in contact with) the medial distal condyle 102 of the patient’s femur 100. Similarly, the alignment surface 46 of the lateral paddle 42 is configured to confront or abut a lateral distal condyle 104 of the patient’s femur 100. In some instances, the alignment surface 46 may also include a shim that confronts (and may be positioned in contact with) the lateral distal condyle 104 of the patient’s femur 100.

[0043] As can be seen in FIG. 1, the medial paddle 40 and the lateral paddle 42 extend parallel to one another in the anterior / posterior direction. Specifically, the longitudinal axis 54 of the medial paddle 40 extends in the anterior / posterior direction and is parallel to the longitudinal axis 56 of the lateral paddle 42 which also extends in the anterior / posterior direction. Such an arrangement allows the alignment surfaces 44, 46 of the paddles 40, 42 to be positioned in the desired orientation for contact with the distal condyles 102, 104 of the patient’s femur 100, respectively.

[0044] Referring again to FIGS. 1-4, the anterior stylus 14 extends superiorly away from the femoral platform 38 and thus the paddles 40, 42 of the alignment guide 12. The anterior stylus 14 includes an inferior end 62 that is secured to the femoral platform 38 and an opposite superior end 64. As can be seen best in FIGS. 1, 3, and 7, the anterior stylus 14 has an alignment surface 66 formed in its superior end 64. The alignment surface 66 is arranged generally perpendicular to the longitudinal axes 28, 30 of the pin guides 20, 22 and the alignment surfaces 44, 46 of the paddles 40, 42. The anterior stylus 14 is configured rotate relative to the medial paddle 40 and the lateral paddle 42 while remaining perpendicular to the medial pin guide 20 and the lateral pin guide 22. In such a way, the alignment surface 66 of the anterior stylus 14 is may be positioned in contact with the anterior surface 106 of the patient’s femur 100 (see FIG. 7). In such a way, when the distal femoral pin guide instrument 10 is positioned on the patient’s femur 100, the anterior stylus 14 functions to position and maintain the pin guides 20, 22 in a desired angle relative to the anterior surface 106 of the femur 100. This angle can be perpendicular to the anterior surface 106 of the patient’s femur100 or can be flexed or extended relative to the anterior surface 106 of the patient’s femur 100, and it thus affects the final sagittal angle of the femoral prosthetic implant component. In the illustrative embodiment described herein, the anterior stylus 14 functions to position and maintain the pin guides 20, 22 such that their respective longitudinal axes 28, 30 are generally perpendicular to the anterior surface 106 of the patient’s femur 100 when the distal femoral pin guide instrument 10 is positioned on the patient’s femur 100. In doing so, the anterior stylus 14 may also function as an intramedullary hole locator.

[0045] As noted above, the anterior stylus 14 is selectively removable from the alignment guide 12. In particular, the femoral platform 38 includes a pin-receiving bore 48 positioned between the medial paddle 40 and the lateral paddle 42. The anterior stylus 14 includes a mounting pin 68 extending posteriorly from its inferior end 62. The mounting pin 68 is received into the pin-receiving bore 48 of the femoral platform 38 so as to removably secure the anterior stylus 14 to the femoral platform 38. In some embodiments, the mounting pin 68 and the surfaces of the platform 38 defining the pin-receiving bore 48 may be embodied with locking features such as tabs and correspondingly-shaped slots to retain the mounting pin 68 in the bore 48. As noted above, when positioned in the pin-receiving bore 48, the mounting pin 68 is rotatable along its longitudinal axis relative to the femoral platform 38, and thus relative to the paddles 40, 42. In such a way, the anterior stylus 14 may be rotated relative to the paddles 40, 42 while remaining perpendicular to the pin guides 20, 22.

[0046] As alluded to above, the distal femoral pin guide instrument 10 also includes a number of shims 90. This shims 90 are configured with varying different sizes (i.e., different thicknesses) so that the surgeon can intraoperatively select a best-fit option to pair with the paddles 40, 42 of the alignment guide 12. For example, the shims 90 of the distal femoral pin guide instrument 10 may be provided in size 1 (e.g., having a 1 mm thickness), size 2 (e.g., having a 2 mm thickness), size 3 (e.g., having a 3 mm thickness), size 4 (e.g., having a 4 mm thickness), and size 5 (e.g., having a 5 mm thickness). Shims 90 of additional sizes may also be provided to fit the needs of a given design of the distal femoral pin guide instrument 10.

[0047] Each of the shims 90 includes a locking mechanism 92 that mates with a locking mechanism 70, 72 of the alignment guide’s paddles 40, 42, respectively. In the illustrative embodiment described herein, the locking mechanism 92 of the shims 90 is embodied as arcuate-shaped rail 94 having a dove-tail cross sectional shape and the locking mechanisms 70, 72 of the alignment guide’s paddles 40, 42 are respectively embodied as a pair of elongated arcuate-shaped slots 74, 76. The elongated arcuate-shaped slots 74, 76 each have a dove-tail cross sectional shape that is sized and shaped to receive the arcuate-shaped rail 94 of the shims90. As such, the rail 94 is configured to slide into the slots 74, 76 such that the dove-tail interface couples the shim 90 to the paddles 40, 42. In another illustrative embodiment, the locking mechanism 92 of the shims 90 is embodied as a post and the locking mechanisms 70, 72 of the alignment guide’s paddles 40, 42 are embodied as a pair of vertical elongated bores extending through the paddles 40, 42. In such an embodiment, the post is sized to be press fit into the elongated bores to couple the shim 90 to the paddles 40, 42.

[0048] In the illustrative embodiment described herein, the shims 90 are “universal” (i.e., not side-specific). In other words, each of the shims 90 may be coupled to either the medial paddle 40 or the lateral paddle 42. However, in some embodiments, the shims 90 may be side-specific and, as a result, specifically-shaped to be coupled to one of the paddles 40, 42, but not both.

[0049] As will be described below in greater detail, during performance of a surgical procedure to prepare the distal end 108 of the patient’s femur 100, the surgeon positions the patient’s knee in extension and determines a desired extension gap indicative of the desired distance between one or both of the medial distal condyle 102 and the lateral distal condyle 104 of the patient’s femur 100 and one or both of the medial plateau 122 and the lateral plateau 124, respectively, of the patient’ s tibia 120. It should be appreciated that the surgeon may make this determination before or after a resection of the patient’s proximal tibia to remove a portion of the tibia. The surgeon may then utilize a shim 90 that has a size (i.e., thickness) that corresponds to the determined desired extension gap on the medial side and / or the lateral side of the patient’s knee. In particular, the surgeon selects a shim 90 having a size (i.e., thickness) that corresponds with the desired extension gap from the differently sized shims 90. It should be appreciated that the selected thickness of the shim and the thickness of the removed portion of the tibia together equal the desired extension gap. After selecting the shim 90, the surgeon may install the selected shim 90 on the corresponding paddle 40, 42.

[0050] In operation, the surgeon may utilize the distal femoral pin guide instrument 10 during performance of an orthopaedic knee procedure to prepare the distal end 108 of the patient’s femur 100 to receive a prosthetic femoral component. To do so, the surgeon may utilize the distal femoral pin guide instrument 10 to install a pair of guide pins 110 on the patient’s femur 100 and thereafter use a distal cutting block 112 to guide a bone saw blade 114 in making a distal cut on the distal end 108 of the patient’s femur 100.

[0051] As shown in FIG. 5, during such an orthopaedic surgical procedure, the surgeon first orientates the patient’s femur 100 and tibia 120 such that the patient’s knee is positioned in extension. With the patient’s knee positioned in extension, the surgeon may use any ofnumerous known techniques to determine the desired extension gaps on each side (i.e., the medial and lateral sides) of the patient’s knee. In particular, as shown in FIG. 5, the surgeon may use any of numerous known techniques to determine a desired medial extension gap 132 indicative of the distance between the medial distal condyle 102 of the patient’s femur 100 and the medial plateau 122 of the patient’s tibia 120. The surgeon may also use any of such known techniques to determine a desired lateral extension gap 134 indicative of the distance between the lateral distal condyle 104 of the patient’s femur 100 and the lateral plateau 124 of the patient’s tibia 120.

[0052] In some cases, the surgeon may resect the patient’s proximal tibia to remove a portion of the tibia before determining the desired extension gap. The final extension gap may therefore be based a distal femoral resection, proximal tibial resection, or a combination of both.

[0053] The specific technique used by the surgeon to determine the desired medial extension gap 132 and the desired lateral extension gap 134 (with the patient’s knee positioned in extension) may be selected based on the needs of a given surgical procedure or the preferences of a given surgeon. Amongst other techniques, the surgeon may use a balanced approach in which the surgeon operates a ligament balancer to position the femur 100 and the tibia 120 of the patient’s knee based on ligament tension and then measures (i) the distance between the medial distal condyle 102 of the patient’s femur 100 and the medial plateau 122 of the patient’s tibia 120 and (ii) the distance between the lateral distal condyle 104 of the patient’s femur 100 and the lateral plateau 124 of the patient’s tibia 120. As a further example, the surgeon may use a kinematic alignment technique in which the surgeon measures cartilage loss and / or other tissue loss within the patient’s knee to position the patient’s knee in a position that represents the native, pre-disease state of the patient’s knee and thereafter selects shims based on the measured cartilage loss. It should be appreciated that any of such techniques may be performed using mechanical instruments, automated instruments, computer-assisted surgical systems, or any other type of instrument, system, or method conventionally used by surgeons to determine the desired extension gaps 132, 134 with the patient’s knee positioned in extension.

[0054] Once the surgeon has determined the desired extension gaps 132, 134 with the patient’s knee positioned in extension, the surgeon then orientates the patient’s femur 100 and tibia 120 so that the patient’s knee is positioned in flexion. The various resections on the patient’s femur 100 and tibia 120 are performed with the patient’s knee positioned in flexion. The surgeon utilizes the distal femoral pin guide instrument 10, along with otherinstrumentation, to surgically prepare the patient’s knee with the desired extension gaps 132, 134 (as they were previously determined with the patient’s knee positioned in extension). It should be appreciated that the distal femoral pin guide instrument 10 is not secured to the patient’s femur 100 prior to positioning the patient’s knee in flexion thereby eliminating the cumbersome process of pinning conventional guides and / or cutting blocks in knee extension and then attempting to move such pinned instruments to knee flexion without altering their pinned positions. Moreover, use of the distal femoral pin guide instrument 10 allows the cutting guide to be positioned with an extramedullary technique as opposed to intramedullary technique.

[0055] Based on the desired extension gaps 132, 134 (as previously determined by the surgeon with the patient’s knee positioned in extension), the surgeon then installs any necessary shims 90 on the alignment guide 12. Specifically, the surgeon selects an appropriately sized shim 90 for each of the paddles 40, 42 based on the previously-determined desired extension gaps 132, 134, respectively. In particular, as shown in FIG. 4, the surgeon selects a shim 90 having a size (i.e., thickness) which corresponds to the desired extension gaps 132, 134 on each side of the patient’s knee (i.e., the medial and lateral sides) and installs it on the respective paddle 40, 42. For example, if the surgeon previously determined that the medial side of the patient’s knee has a desired extension gap 132 of 4 mm, the surgeon selects a size 4 (4 mm thick) shim 90 and installs it on the medial paddle 40 of the alignment guide 12. Similarly, for example, if the surgeon previously determined that the lateral side of the patient’s knee has a desired extension gap 134 of 2 mm, the surgeon selects a size 2 (2 mm thick) shim 90 and installs it on the lateral paddle 42 of the alignment guide 12. It should be appreciated that if the surgeon previously determined that either side (or both sides) of the patient’s knee does not require an augmented extension gap, a shim 90 is not installed on the respective paddle(s) 40, 42. For example, if the surgeon previously determined that the medial side of the patient’s knee has a desired extension gap 132 of 2 mm, but the lateral side of the patient’s knee does not require an augmented extension gap, the surgeon selects a size 2 (2 mm thick) shim 90 and installs it on the medial paddle 40 of the alignment guide 14, but does not install any shims 90 on the lateral paddle 42. It should be appreciated that the selected thickness of the shim and the thickness of the removed proximal portion of the tibia together equal the desired extension gap-

[0056] Once the surgeon has both positioned the patient’s knee in flexion and installed the selected shims 90 (if any) on both the paddles 40, 42, the surgeon positions the assembled distal femoral pin guide instrument 10 on the distal end 108 of the patient’s femur 100, asshown in FIGS. 6 and 7. In particular, the surgeon positions the instrument 10 such that the alignment surface 44 of the medial paddle 40 (including any shims 90 included therewith) is positioned in contact with the medial distal condyle 102 of the patient’s femur 100, the alignment surface 46 of the lateral paddle 42 (including any shims 90 included therewith) is positioned in contact with the lateral distal condyle 104 of the patient’s femur 100, and the alignment surface 66 of the anterior stylus 14 is positioned in contact with the anterior surface 106 of the patient’s femur 100. Doing so positions the pin guides 20, 22 (and then ultimately the distal cutting block 112) in a position based off the desired extension gaps 132, 134 (as they were previously determined with the patient’s knee positioned in extension) since the size (i.e., thickness) of the installed shims 90 account for the desired gaps 132, 134. In arriving at such a position, the surgeon may apply a light pressure on the anterior stylus 14 to confirm proper contact between the stylus 14 and the femur 100.

[0057] Once the surgeon is satisfied with the alignment of the alignment guide 12, the surgeon may pin the distal femoral pin guide instrument 10 to the distal end 108 of the patient’s femur 100 by installing a pair of guide pins 110 through guide bores 24, 26 of the pin guides 20, 22, respectively. With the guide pins 110 installed on the distal end 108 of the patient’s femur 100, the surgeon removes the distal femoral pin guide instrument 10 and thereafter installs the distal cutting block 112 on the guide pins 110, as shown in FIG. 8. As also shown in FIG. 8, the surgeon may then use the distal cutting block 112 to perform a distal resection of the distal end 108 of the patient’s femur 100. Specifically, the surgeon may advance the bone saw blade 114 of a surgical saw through the distal cutting slot 116 to engage the patient’s femur 100 and operate the surgical saw to surgically form a planar distal resected surface of the patient’s femur 100. The surgeon may then pin an additional cutting block, such as a 4-in-l cutting block (not shown) on the surgically-prepared distal resected surface and thereafter perform additional resections such as an anterior cut, a posterior cut, and a pair of chamfer cuts. Once the anterior cut, posterior cut, and both chamfer cuts have been made, the surgeon removes the 4-in-l cutting block from the patient’s femur and completes the orthopaedic knee procedure.

[0058] It should be appreciated that use of the distal femoral pin guide instrument 10 allows the surgeon to transfer measurements (e.g., the desired extension gaps) obtained with the patient’s knee positioned in extension to a desired alignment of the distal cutting block 112 with the patient’s knee positioned in flexion without requiring the surgeon to position the block in extension and then maintain the alignment of the block while moving the bones of the knee to flexion. It should also be appreciated that the distal femoral pin guide instrument 10 may beembodied with other features to fit the needs of a given design. For example, the alignment guide 12 may be embodied with arms 50, 52 that pivot and / or rotate relative to the femoral platform 38 to provide additional alignment flexibility. In addition, the distal cutting block 112 may be integrated into the design of the distal femoral pin guide instrument 10.

[0059] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.

[0060] There are a plurality of advantages of the present disclosure arising from the various features of the method, apparatus, and system described herein. It will be noted that alternative embodiments of the method, apparatus, and system of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the method, apparatus, and system that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present disclosure as defined by the appended claims.

Claims

CLAIMS1. An orthopaedic surgical instrument for use in the surgical preparation of a patient’s femur during performance of an orthopaedic knee procedure, the orthopaedic surgical instrument comprising: a medial pin guide having an elongated guide bore, the elongated guide bore of the medial pin guide has a longitudinal axis extending in the anterior / posterior direction, a lateral pin guide having an elongated guide bore, the elongated guide bore of the lateral pin guide has a longitudinal axis extending in the anterior / posterior direction so as to be parallel with the longitudinal axis of the elongated guide bore of the medial pin guide, a medial paddle spaced apart inferiorly from the medial pin guide, the medial paddle having an alignment surface that extends parallel to the longitudinal axis of the elongated guide bore of the medial pin guide and is configured to be positioned in contact with a medial distal condyle of the patient’s femur, a lateral paddle spaced apart inferiorly from the lateral pin guide, the lateral paddle having an alignment surface that extends parallel to the longitudinal axis of the elongated guide bore of the lateral pin guide and is configured to be positioned in contact with a lateral distal condyle of the patient’s femur, and an anterior stylus extending superiorly away from the medial paddle and the lateral paddle, the anterior stylus having an alignment surface that is configured to be positioned in contact with an anterior surface of the patient’s femur.

2. The orthopaedic surgical instrument of claim 1, wherein the alignment surface of the anterior stylus extends perpendicularly to both the longitudinal axis of the elongated guide bore of the medial pin guide and the longitudinal axis of the elongated guide bore of the lateral pin guide.

3. The orthopaedic surgical instrument of claim 1, further comprising a femoral platform, wherein: the medial paddle and the lateral paddle are formed in the femoral platform, the anterior stylus includes an inferior end secured to the platform and an opposite superior end, and the alignment surface of the anterior stylus is formed in its superior end.

4. The orthopaedic surgical instrument of claim 1, wherein the anterior stylus is rotatable relative to the medial paddle and the lateral paddle.

5. The orthopaedic surgical instrument of claim 1, further comprising a plurality of shims, wherein: each of the plurality of shims has a thickness that is different from the thickness of at least some of the other of the plurality of shims, and each of the plurality of shims includes a locking mechanism that mates with a locking mechanism of the medial paddle and the lateral paddle such that each of the plurality of shims is configured to be separately coupled to both the medial paddle and the lateral paddle.

6. The orthopaedic surgical instrument of claim 1, further comprising a plurality of shims, wherein: each of the plurality of shims has a thickness that is different from the thickness of at least some of the other of the plurality of shims, and each of the plurality of shims includes a locking mechanism that mates with a locking mechanism of one or both of the medial paddle and the lateral paddle such that each of the plurality of shims is configured to be separately coupled to one or both of the medial paddle and the lateral paddle.

7. The orthopaedic surgical instrument of claim 6, wherein: the locking mechanism of each of the plurality of shims comprises an arcuateshaped rail, and the locking mechanism of the medial paddle and the lateral paddle comprises an arcuate-shaped slot configured to receive the arcuate-shaped rail of each of the plurality of shims.

8. The orthopaedic surgical instrument of claim 6, wherein: the locking mechanism of each of the plurality of shims comprises a post, and the locking mechanism of the medial paddle and the lateral paddle comprises an elongated bore configured to receive the post of each of the plurality of shims.

9. The orthopaedic surgical instrument of claim 1, further comprising a femoral platform, wherein: the medial paddle and the lateral paddle are formed in the femoral platform, a medial arm extends superiorly away from the platform, the medial pin guide is secured to a superior end of the medial arm, a lateral arm extends superiorly away from the platform, and the lateral pin guide is secured to a superior end of the lateral arm.

10. A method of surgically preparing a femur and a tibia of a knee of a patient during performance of an orthopaedic knee procedure, the method comprising: determining, with the patient’ s knee positioned in extension, (i) a desired medial extension gap indicative of a distance between a medial condyle of the patient’s femur and a medial plateau of the patient’s tibia, and (ii) a desired lateral extension gap indicative of a distance between a lateral condyle of the patient’s femur and a lateral plateau of the patient’s tibia, selecting a medial shim having a thickness that corresponds to the determined medial extension gap from a plurality of shims of differing thicknesses and installing the selected medial shim onto a medial paddle of a femoral pin guide instrument, selecting a lateral shim having a thickness that corresponds to the determined lateral extension gap from a plurality of shims of differing thicknesses and installing the selected lateral shim onto a lateral paddle of the femoral pin guide instrument,positioning, with the patient’s knee positioned in flexion, the femoral pin guide instrument on a distal end of the patient’s femur such that (i) the femoral shim installed on the medial paddle of the femoral pin guide instrument contacts a medial distal femoral condyle of the patient’s femur, (ii) the femoral shim installed on the lateral paddle of the femoral pin guide instrument contacts a lateral distal femoral condyle of the patient’s femur, and (iii) an anterior stylus of the femoral pin guide instrument contacts an anterior surface of the patient’s femur, and installing, with the femoral pin guide instrument positioned on the distal end of the patient’s femur, a pair of guide pins into the distal end of the patient’s femur.

11. The method of claim 10, wherein determining the desired medial extension gap and the desired lateral extension gap comprises operating a ligament balancer to balance the patient’s knee.

12. The method of claim 10, wherein determining the desired medial extension gap and the desired lateral extension gap comprises mechanically aligning the patient’s knee.

13. The method of claim 10, wherein determining the desired medial extension gap and the desired lateral extension gap comprises determining an amount of cartilage loss within the patient’s knee.

14. The method of claim 10, further comprising: installing a distal cutting block on the pair of guide pins, and performing a distal resection of the distal end of the patient’s knee so as to produce a planar resected surface by use of the distal cutting block.

15. A method of surgically preparing a femur and a tibia of a knee of a patient during performance of an orthopaedic knee procedure, the method comprising: determining, with the patient’s knee positioned in extension, a desired extension gap indicative of a distance between a condyle of the patient’s femur and a plateau of the patient’s tibia, selecting a shim having a thickness based on the determined extension gap from a plurality of shims of differing thicknesses and installing the selected shim onto a paddle of a femoral pin guide instrument,positioning, with the patient’s knee positioned in flexion, the femoral pin guide instrument on a distal end of the patient’s femur such that the femoral shim installed on the paddle of the femoral pin guide instrument contacts a distal femoral condyle of the patient’s femur, and installing, with the femoral pin guide instrument positioned on the distal end of the patient’s femur, a pair of guide pins into the distal end of the patient’s femur.

16. The method of claim 15, wherein determining the desired extension gap comprises operating a ligament balancer to balance the patient’s knee.

17. The method of claim 15, wherein determining the desired extension gap comprises mechanically aligning the patient’s knee.

18. The method of claim 15, wherein determining the desired extension gap comprises determining an amount of cartilage loss within the patient’s knee.

19. The method of claim 15, further comprising: installing a distal cutting block on the pair of guide pins, and performing a distal resection of the distal end of the patient’s knee so as to produce a planar resected surface by use of the distal cutting block.

20. The method of claim 15, wherein: determining the desired extension gap comprises determining, with the patient’s knee positioned in extension, a desired medial extension gap indicative of a distance between a medial condyle of the patient’s femur and a medial plateau of the patient’s tibia, selecting the shim comprises selecting a medial shim having a thickness that corresponds to the determined medial extension gap from a plurality of shims of differing thicknesses and installing the selected medial shim onto a medial paddle of the femoral pin guide instrument, and positioning the femoral pin guide comprises positioning, with the patient’s knee positioned in flexion, the femoral pin guide instrument on the distal end of the patient’s femur such that the medial shim installed on the medial paddle of the femoral pin guide instrument contacts a distal femoral condyle of the patient’s femur.

21. The method of claim 15, wherein: determining the desired extension gap comprises determining, with the patient’s knee positioned in extension, a desired lateral extension gap indicative of a distance between a lateral condyle of the patient’s femur and a lateral plateau of the patient’s tibia, selecting the shim comprises selecting a lateral shim having a thickness that corresponds to the determined lateral extension gap from a plurality of shims of differing thicknesses and installing the selected lateral shim onto a lateral paddle of the femoral pin guide instrument, and positioning the femoral pin guide instrument comprises positioning, with the patient’s knee positioned in flexion, the femoral pin guide instrument on the distal end of the patient’s femur such that the lateral shim installed on the lateral paddle of the femoral pin guide instrument contacts a distal femoral condyle of the patient’s femur.

22. The method of claim 15, wherein selecting the shim having the thickness based on the determined extension gap comprises selecting a shim having a thickness that corresponds to the determined extension gap.

23. The method of claim 15, further comprising: resecting a proximal end of a patient’s tibia to remove a portion of the patient’s tibia having a thickness based on the determined extension gap, and wherein a sum of the thickness of the resected portion of the patient’s tibia and the thickness of the shim corresponds to the determined extension gap.

Images