Devices, systems and methods for monitoring hip replacements

Abstract

A replacement hip joint is provided. [Solution] A replacement artificial hip joint is provided, characterized by having an artificial femoral stem, an artificial femoral head connected to the femoral stem, an artificial acetabulum assembly connected to the femoral head, and a plurality of sensors connected to at least one of the femoral stem, the femoral head, and the acetabulum assembly.

Description

[Technical Field]

[0001] The present invention relates generally to hip replacement surgery, and more particularly to instruments and methods for monitoring the performance of total and partial hip replacement surgeries.

[0002] Description of Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 61 / 789,170, filed March 15, 2013, under 35 U.S.C. § 119(e), which is incorporated by reference in its entirety. [Background technology]

[0003] Hip replacement surgery is one of the most common orthopedic procedures. It may be performed when a patient has lost full use of the hip joint, typically due to trauma to the hip joint, avascular necrosis of the hip joint, or for the treatment of severe and / or persistent joint pain (e.g., due to various types of arthritis, such as rheumatoid arthritis or osteoarthritis).

[0004] Hip replacements can take many different forms. In a total hip replacement, or total hip replacement (THR), both the femoral head and acetabulum are replaced. In a hemi- (partial) hip arthroplasty, only the femoral head is replaced, while the patient's own acetabulum is retained. The femoral component of a hip replacement may be a single piece, with the head and stem as one complete unit, or it may be made in several pieces, such as bonding a prosthetic femoral stem to a separate femoral head component and neck section (often to provide a custom fit for the patient based on length and / or femoral head size). The femoral component may be cemented in place with bone cement (cemented hip joint) or may be held in place without cement by fitting the femoral component precisely within the femoral intermedullary space of the femur (AML - anatomic medullary locking - stem design). Similarly, the acetabular component of a THR may also be a single piece that is attached to the hip joint space to receive the femoral head, or it may be a two-piece component that includes a shell that is attached to the pelvic bone and an inner liner attached to the shell. The acetabular component of a THR may be held in place with screws and / or cement, or it may be attached without cement.

[0005] Currently, various components may be made of the same material (e.g., all parts may be made of metal), or individual components may be made of a variety of materials. For example, acetabular components typically have a metal shell with an outer coating to facilitate bone attachment and ingrowth, and an inner liner made of polyethylene, ultra-high molecular weight polyethylene, ceramic, or surgical stainless steel. Similarly, there may be several different combinations of materials used to construct the femoral head. For example, the femoral head may be composed of a metal, usually cobalt chrome (although stainless steel or titanium may also be used) or a ceramic material, while the femoral stem is typically metal (stainless steel, titanium, or cobalt chrome) and often has a surface coating to promote bonding of the implant within the femur.

[0006] Figure 1 shows a complete hip prosthesis of a type known in the art. Figure 2 shows an exploded view of the complete hip prosthesis of Figure 1. The acetabular shell (which, unless the context requires otherwise, is meant to refer to "prosthetic acetabular shell" even when not otherwise specified) can be made of any suitable material, preferably metal or ceramic, and the inner liner can also be made of any suitable material that is compatible with the material for the acetabular shell. For example, the liner can be made of polyethylene, ultra-high molecular weight polyethylene, ceramic, metal, or other types of materials. The femoral head (hereinafter referred to as "prosthetic femoral head" unless the context requires otherwise, even if not otherwise specified) may be made of metal or ceramic and may be of the same or a different material as that constituting the acetabular liner (hereinafter referred to as "prosthetic acetabular liner" unless the context requires otherwise, even if not otherwise specified), such as a ceramic femoral head on a ceramic acetabular liner (ceramic-on-ceramic hip joint; COC), a metal femoral head on a metal acetabular liner (metal-on-metal hip joint; MOM) or alternatively a metal or ceramic femoral head on a polyethylene acetabular liner (metal-on-polyurethane, MOP; metal-on-crosslinked polyurethane, MOXP; ceramic-on-polyurethane, COP; ceramic-on-crosslinked polyurethane, COXP), or other combinations thereof. A femoral stem (which will also be referred to hereinafter as "prosthetic femoral stem" unless the context requires otherwise) is typically made of a biocompatible metal (stainless steel, titanium, cobalt chrome) for long-term use within the patient's body, and is inserted into the femoral shaft and held in place with or without bone cement.

[0007] Unfortunately, inserting a total hip joint can result in various complications over time. For example, as shown in Figure 3, wear can occur between the femoral head and the acetabular liner, resulting in improper hip prosthesis movement. In addition, patients can experience inflammation and pain from even slight movement or displacement of any of the components. Depending on the type of material used for the acetabular liner (if present, as in THR) and femoral head (both THR and hemiarthroplasty), wear can occur in the acetabular liner and / or femoral head, resulting in loosening or partial (or complete) displacement of the joint and poor hip joint performance, resulting in difficulty moving and walking, and causing pain and inflammation for the patient. A second common complication is bone loss over time (e.g., 8-12 years) in the tissues surrounding the implant in either the pelvis and / or femur due to a process known as bone softening or osteolysis.

[0008] Bone erosion around implants can be caused by material debris (metal, ceramic, and / or polyurethane fragments) generated by friction between the femoral head and the acetabular cup, which can penetrate the tissue surrounding the implant and cause inflammation and bone loss. Other potential causes of inflammation and bone softening are vibration and movement of the implant, mechanical wear and tear, lack of biocompatibility between the implant material and the surrounding bone, metal allergies, and lack of biocompatibility between the bone cement and the surrounding bone. Additional complications include infection, nerve injury, material sensitivity, nerve impingement, and hip dislocation (which is more likely if muscles have not fully healed, usually during the first 4 to 12 weeks after surgery).

[0009] Currently, postoperative in-hospital monitoring of patients undergoing hip replacement surgery is performed by personal visits by hospital staff and medical teams, including medical monitoring (e.g., vital signs), assessment of hip range of motion (ROM), physical therapy (including early mobilization and activity), and diagnostic imaging and blood studies as needed. Once the patient is discharged from the hospital, prosthesis performance and patient satisfaction are monitored during regular physician office visits, where a complete medical history, physical examination, and complementary imaging and diagnostic studies are used to monitor the patient's progress and identify any potential complications. During these visits, the surgeon typically assesses the hip's range of motion, attempts to identify any pain that occurs during certain movements or activities, and questions the patient to determine activity level, daily function, pain control, and rehabilitation progress. Summary of the Invention [Problem to be solved by the invention]

[0010] Unfortunately, the majority of a patient's recovery occurs between hospital or clinic visits. Accurately measuring and tracking total joint range of motion (ROM may vary depending on pain control, the level of anti-inflammatory medication, time of day, recent activity, and / or how the patient feels at the time of consultation), "real-life" prosthesis performance, patient activity level, exercise tolerance, and the effectiveness of rehabilitation efforts (physical therapy, medications, etc.) from the date of surgery through to full recovery can be extremely difficult. For much of this information, physicians rely on patient self-report or third-party observation to gain insight into postoperative treatment effectiveness and the recovery and rehabilitation process; often, this is further complicated by patients who are unclear about what to look for, unfamiliar with "normal / expected" postoperative recovery, non-compliant, or unable to effectively communicate these symptoms. Furthermore, identifying and tracking complications (in and out of hospital) before they become symptomatic and occur between physician visits, or whose presence is difficult to detect, also provides valuable additional information for the management of THR patients. Currently, in all cases, neither physicians nor patients have access to the type of "real-time," continuous, objective prosthesis performance measurement they might otherwise have. [Means for solving the problem]

[0011] The present invention discloses novel total and partial hip replacements that overcome many of the shortcomings of conventional artificial hip joints, methods for constructing and monitoring these novel hip replacements, and further provides other related advantages.

[0012] In summary, total and partial hip prostheses are provided that include a number of sensors for monitoring the health and effectiveness of the prosthesis within the patient. The sensors may be located on the exterior surface of the prosthesis, on the interior surface of the prosthesis, within the prosthesis material itself (stainless steel, titanium, cobalt chrome, polyurethane, high molecular weight polyurethane, ceramics, etc.), between the various components that make up the prosthesis, within the bone cement (e.g., PMMA or PMMA and MMA copolymer blends) used to secure the prosthesis (if present), and / or within the tissue surrounding the prosthesis. In certain embodiments, the sensors are passive, and thus do not require their own power source.

[0013] One aspect of the present invention provides an assembly for positioning and deploying an implant within a patient, including a total or partial hip prosthesis and sensors disposed on, within, or around the hip prosthesis. In various embodiments, the sensors may be located on the exterior surface of the hip prosthesis, on the interior surface of the hip prosthesis, within the material used to construct the hip prosthesis, between the various components that make up the hip prosthesis, on or within bone cement used to secure the hip prosthesis, on or within tissues surrounding the hip prosthesis (typically bone or bone marrow, but also muscle, ligaments, tendons, joint capsule, and / or synovial compartment), or any combination thereof. Representative examples of sensors suitable for use within the present invention include accelerometers (acceleration sensors, tilt sensors, vibration sensors, shock sensors, and rotation sensors), pressure sensors, contact sensors, position sensors, chemical microsensors, tissue metabolism sensors, mechanical stress sensors, and temperature sensors. In particularly preferred embodiments, the sensors are wireless sensors or sensors connected to a wireless microprocessor.

[0014] In another embodiment, multiple sensors as described above are placed on, in, or around the hip joint prosthesis (bone cement or tissue), and in a preferred embodiment, the hip joint prosthesis may include one or more types of sensors (e.g., one or more of the following sensors: acceleration sensors, tilt sensors, vibration sensors, shock sensors, rotation sensors, pressure sensors, contact sensors, position sensors, chemical microsensors, tissue metabolism sensors, and mechanical stress sensors, or any combination thereof).

[0015] According to various embodiments, sensors are placed at various locations within the replacement hip prosthesis to monitor the action, motion, function, wear, performance, potential side effects, and medical condition of the prosthesis and its interface with the patient's living tissue. Live, continuous, in-situ monitoring of patient activity, patient function, prosthesis activity, prosthesis function, prosthesis performance, and potential side effects is provided. In addition, information is available about many aspects of the replacement hip prosthesis and its interaction with the patient's own body tissue, including clinically important measurements not currently available through anthropometry, medical imaging, and diagnostic medical studies.

[0016] According to one embodiment, sensors provide assessment data regarding the range of motion (ROM) of the prosthetic hip joint. Currently, ROM is typically measured clinically by a physician passively moving the prosthetic hip joint through its range of motion during a physical examination and recording the results (flexion, extension, abduction, adduction, external rotation, internal rotation, and degree of rotation during flexion). Motion sensors and accelerometers can be used to accurately determine the total ROM of the prosthetic hip joint both during the physical examination and during normal daily activities between visits.

[0017] According to one embodiment, contact sensors are provided between the prosthesis and the surrounding bone, between the prosthesis and the surrounding bone cement, and / or between the bone cement and the surrounding bone to measure bone erosion and loosening around the implant. In other embodiments, strain gauges are provided to detect strain between the prosthesis and the surrounding bone, between the prosthesis and the surrounding bone cement, between the bone cement and the surrounding bone, and also strains exerted on various portions of the prosthesis. It is understood that a sudden increase in strain can impose excessive stress on the replacement prosthesis, thereby causing significant damage to the body. For example, a gradual decrease in strain over a long period of time can cause resorption of bone around the implant, resulting in loosening of the prosthesis or fracture around the prosthesis.

[0018] According to other embodiments, accelerometers are provided to detect vibration, shock, tilt, and rotation. In other embodiments, sensors that measure surface wear, such as contact or pressure sensors, may be embedded at various depths within the femoral head, acetabulum, and / or acetabular cup to monitor the articular surface. In other embodiments, position sensors and other types of sensors are provided to indicate range of motion and monitor for partial (or complete) hip dislocation during actual use over a period of time.

[0019] In another embodiment, a hip prosthesis (full or partial) can have sensors at a density specified for a particular placement location. For example, a hip prosthesis can have a sensor density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, or greater than 10 sensors (e.g., acceleration sensors, tilt sensors, vibration sensors, impact sensors, rotation sensors, pressure sensors, contact sensors, position sensors, chemical microsensors, tissue metabolism sensors, and mechanical stress sensors, or any combination thereof) per square centimeter of device. In other embodiments, a hip prosthesis (full or partial) can have a sensor density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, or greater than 10 sensors (e.g., acceleration sensors, tilt sensors, vibration sensors, impact sensors, rotation sensors, pressure sensors, contact sensors, position sensors, chemical microsensors, tissue metabolism sensors, and mechanical stress sensors, or any combination thereof) per cubic centimeter of device. In related embodiments, sensors (e.g., acceleration sensors, tilt sensors, vibration sensors, impact sensors, rotation sensors, pressure sensors, contact sensors, position sensors, chemical microsensors, tissue metabolism sensors, and mechanical stress sensors) may be placed at specific locations on, in, or around the hip prosthesis, including, for example, in the prosthetic femoral stem, prosthetic femoral neck, prosthetic femoral head, acetabular cup, acetabular liner, various parts of the devices to be connected (e.g., the connecting segments of the femoral stem, femoral neck and femoral head, the connecting segments of the acetabular cup and acetabular liner), and around the hip prosthesis (on or in the bone cement used to fix the hip prosthesis, on or in the tissues around the hip prosthesis, typically on or in the bone or bone marrow, but also on or in the muscles, ligaments, tendons, joint capsule, and / or synovial compartment).

[0020] In certain embodiments of the invention, the total or partial hip prosthesis is provided with a specific unique identification number, and in other embodiments, each of the sensors on, in, or around the hip prosthesis has either a specific unique identification number or a group identification number (e.g., an identification number identifying the sensor as an acceleration sensor, tilt sensor, vibration sensor, shock sensor, rotation sensor, pressure sensor, contact sensor, position sensor, chemical microsensor, tissue metabolism sensor, or mechanical stress sensor). In yet other embodiments, the specific unique identification number or group identification number is specifically associated with a location on, in, or around the hip prosthesis.

[0021] In another aspect of the present invention, a method of monitoring an implanted total or partial hip prosthesis is provided, the method comprising the steps of transmitting a wireless electrical signal from a location outside the body to a location inside the body, receiving the electrical signal at a sensor located on, in or around the hip prosthesis located inside the body, powering the sensor using the received signal, detecting data at the sensor, and outputting the detected data from the sensor to a receiving unit located outside the body.

[0022] The health of the partial or total hip prosthesis can be wirelessly queried and the results reported periodically, allowing the patient's health to be checked periodically or at any time desired by the patient and / or physician.

[0023] In another embodiment, each of the sensors includes a signal receiving circuit and a signal output circuit. The signal receiving circuit receives an interrogation signal that includes both power and data collection request components. Using power from the interrogation signal, the sensor activates the portions of the circuitry necessary to perform the detection, performs the detection, and then outputs data to the interrogation module. The interrogation module operates under the control of a control unit that includes appropriate I / O circuitry, memory, a controller in the form of a microprocessor, and other circuitry for driving the interrogation module. In yet another embodiment, the sensors (e.g., acceleration sensors, tilt sensors, vibration sensors, shock sensors, rotation sensors, pressure sensors, contact sensors, position sensors, chemical microsensors, tissue metabolism sensors, or mechanical stress sensors) are configured so that they can be easily incorporated into or otherwise mechanically attached to the hip joint prosthesis (e.g., via openings or other attachments that allow the sensor to be permanently attached to the hip joint prosthesis) and / or into the bone cement or tissue surrounding the hip joint prosthesis.

[0024] In yet another aspect of the present invention, there is provided a method or apparatus suitable for transmitting a wireless electrical signal from a location outside the body to a location inside the body, receiving the electrical signal with one of the above-mentioned sensors located on, in or around a hip joint prosthesis located inside the body, powering the sensor using the received signal, detecting data at the sensor, and outputting the detected data from the sensor to a receiving unit located outside the body. In certain embodiments, the receiving unit is capable of analyzing the signal provided by the sensor.

[0025] The data collected by the sensor can be stored in memory located within the prosthetic femoral stem. During a visit to a physician, the data can be downloaded by the wireless sensor, providing the physician with data representing the real-time performance of the prosthesis.

[0026] Advantages include more accurate monitoring of the prosthesis and accurate, on-the-spot medical reporting of data that contributes to patient health. Details of one or more embodiments are set forth in the description below. Other features, objects, and advantages will be apparent from the specification, drawings, and claims. Additionally, all patents and patent applications cited herein are incorporated by reference, and the disclosures thereof are incorporated herein in their entirety. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is an isometric view of a total hip replacement. [Figure 2] FIG. 2 is an exploded view of the total hip replacement of FIG. 1. [Figure 3] FIG. 1 illustrates a total hip replacement in a patient's pelvis. [Figure 4] FIG. 1 is an exploded view of a total hip prosthesis equipped with sensors according to various embodiments described herein. [Figure 5] 5 shows the embodiment of FIG. 4 after replacement of the hip prosthesis, illustrating the location of contact with the patient's bone. [Figure 6A] FIG. 2 is an exploded view of an acetabular cup, liner, and femoral prosthesis with various sensors in accordance with various embodiments described herein. [Figure 6B] 1A and 1B are diagrams showing how strain gauges are incorporated into various locations. [Figure 7A] FIG. 1 is a side view of a prosthetic femoral implant with a ball attached. [Figure 7B] FIG. 1 is a side close-up view of a prosthetic femoral implant with various sensors and power-generating segments. [Figure 8A] FIG. 1 is a top view of an acetabular cup having various sensors in accordance with embodiments described herein. [Figure 8B] FIG. 10 shows a liner in the acetabular cup of FIG. 9 provided with various sensors. [Figure 9]FIG. 1 is a side view of an assembled total hip prosthesis including examples of various sensor placement locations. [Figure 10] FIG. 10 shows the entire hip prosthesis assembly of FIG. 9 in a fully functional state within a patient, with various different types of sensors. [Figure 11A] 1A-1C illustrate the movements of a prosthetic hip joint that can be measured and monitored in accordance with various embodiments disclosed herein. [Figure 11B] 1A-1C illustrate the movements of a prosthetic hip joint that can be measured and monitored in accordance with various embodiments disclosed herein. [Figure 12] FIG. 1 illustrates an information and communication technology system embodiment configured for processing sensor data. [Figure 13] FIG. 2 is a block diagram of a sensor, an interrogation module, and a control unit according to one embodiment of the present invention. [Figure 14] 1 is a schematic illustration of one or more sensors positioned on a hip replacement within a patient being probed to obtain and output data in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Briefly described, the present invention provides a variety of hip replacement devices that can be utilized to monitor the health and effectiveness of the device. However, before describing the invention, it may be helpful to an understanding of the invention to first provide definitions of certain terms that will be used below.

[0029] "Hip replacement," as the term is used herein, can take a variety of different forms and may involve replacing all or part of a patient's hip joint with synthetic material. In a total hip replacement or total hip replacement (THR), both the femoral head and acetabulum are replaced. In a hemi- (partial) hip arthroplasty, only the femoral head is replaced, while the patient's own acetabulum is retained. The femoral component of a hip replacement may be a single piece, with the head and stem as one complete unit, or it may be made in several pieces, such as mating a prosthetic femoral stem with a separate femoral head component and neck section (this is often done to provide a custom fit for the patient based on length and / or femoral head size). The femoral component may be cemented in place with PMMA bone cement (glued hip joint) or may be held in place without cement by fitting the femoral component precisely within the femoral intermedullary space of the femur (AML - anatomic medullary locking - stem design). Similarly, the acetabular component of a THR may also be a single piece that is bonded to the hip joint space to receive the femoral head, or it may be a two-piece component that includes a shell that is bonded to the pelvic bone and an inner liner attached to the shell. The acetabular component of a THR may be held in place with screws and / or cement, or may be attached without cement.

[0030] Currently, various components may be made of the same material (e.g., all parts may be made of metal), or individual components may be made of a variety of materials. For example, acetabular components typically have a metal shell with an outer coating to facilitate bone attachment and ingrowth, and an inner liner made of polyethylene, ultra-high molecular weight polyethylene, ceramic, or surgical stainless steel. Similarly, there may be several different combinations of materials used to construct the femoral head. For example, the femoral head may be composed of a metal, usually cobalt chrome (although stainless steel or titanium may also be used) or a ceramic material, while the femoral stem is typically metal (stainless steel, titanium, or cobalt chrome) and often has a surface coating to promote bonding of the implant within the femur.

[0031] As used herein, unless the context specifically requires otherwise, the terms "hip implant" or "hip replacement" or "hip replacement or portion thereof" or "medical device" should be understood to mean any or all of the various components that make up a total hip prosthesis, including, for example, a prosthetic femoral stem, a prosthetic femoral head and acetabular assembly, and the various subcomponents thereof. The term "prosthetic hip joint" should be understood to mean either a partial or total hip prosthesis.

[0032] "Sensor" refers to a device that can be used to measure one or more different aspects of the human body, a hip implant inserted therein, and / or the health, impact, effectiveness, or performance of a hip implant inserted therein. Representative examples of sensors suitable for use in the present invention include, for example, fluid pressure sensors, contact sensors, position sensors, pulse pressure sensors, blood volume sensors, blood flow sensors, chemical sensors (e.g., for blood and / or other bodily fluids), metabolic sensors (e.g., for blood and / or other bodily fluids), accelerometers, mechanical stress sensors, and temperature sensors. In certain embodiments, the sensors may be wireless sensors, or in other embodiments, the sensors may be connected to a wireless microprocessor. In another embodiment, one or more (including all) of the sensors may have a unique sensor identification number ("USI") that specifically identifies the sensor.

[0033] A wide variety of sensors (also known as microelectromechanical systems or "MEMS" or nanoelectromechanical systems or "NEMS," and BioMEMS or BioNEMS, see generally https: / / en.wikipedia.org / wiki / MEMS) can be used in the present invention. Representative patents and patent applications include U.S. Pat. No. 7,383,071 and U.S. Patent Application Publication No. 2010 / 0285082. Representative publications include Albert Foch, "Introduction to BioMEMS," CRC Press, 2013; Marc J. Madow, "From MEMS to Bio-MEMS and Bio-NEMS: Manufacturing Techniques and Applications," CRC Press, 2011; Simona Badilescu, "Bio-MEMS: Science and Engineering Perspectives," CRC Press, 2011; and Steven S. Saliterman. S.Saliterman), "Fundamentals of BioMEMS and Medical Microdevices", SPIE - The International Society of Optical Engineering, 2006; Wanjunn Wang and Steven A. Soper (eds.), "Bio-MEMS: Technologies and Applications", CRC Press, 2012; Volker Kempe, "Inertial MEMS: Principles and Practice", Cambridge University Press Press), 2011. Polla, DL et al., "Microdevices in Medicine", Annual Review of Biomedical Engineering (Ann. Rev. Biomed. Eng.), 2000, Vol. 2, pp. 551-576. Yun, KS et al., "A Surface-Tension Driven Micropump for Low-Voltage and Low Power Operations", J. Microelectromechanical Sys., October 2002, 11:5. Yeh, R. et al.), "Single Mask, Large Force, and Large Displacement Electrostatic Linear Inchworm Motors," J. Microelectromechanical Sys., August 2002, 11:4, pp.330-336; Loh, NC et al., "Sub-10cm. 3 Interferometric Accelerometer with Nano-G Resolution (Sub-10cm 3 "Interferometric Accelerometer with Nano-g Rsolution," J. Microelectromechanical Sys., June 2002, 11:3, pp. 182-187, all of which publications are incorporated by reference herein in their entireties.

[0034] To further understand the various aspects of the invention provided herein, the following sections are provided below: A. Medical Uses of Hip Implants; B. Exemplary Embodiments of Hip Implants; C. Coatings Applied to Hip Implants; D. Drug-Eluting Hip Implants; E. Methods of Monitoring Infection in Hip Implants; F. Power Generation; G. Medical Uses of Sensors; H. Medical Imaging and Self-Diagnosis, Predictive Analysis, and Predictive Maintenance of Assemblies Including Hip Implants; I. Methods of Monitoring Assemblies Including Hip Implants; and J. Collection, Transmission, Analysis, and Distribution of Data from Assemblies Including Hip Implants.

[0035] A. Medical Use of Hip Replacements Hip replacement is performed when a patient loses sufficient use of the hip joint, resulting in disability, loss of motion and function, impaired ambulation, and / or persistent joint pain and discomfort. Common causes of hip dysfunction leading to total or partial hip replacement include trauma (typically a hip fracture, often at the femoral neck), avascular necrosis of the hip joint, or various forms of arthritis (e.g., rheumatoid arthritis or osteoarthritis). In most patients, surgery is successful in improving ambulation, restoring function, and reducing pain, and as a result, this surgery is one of the most common orthopedic procedures in the Western world.

[0036] B. Exemplary Embodiments of Hip Implants 4 shows a prosthesis 10 in the form of a hip replacement incorporating one or more sensors 22 as described herein. The hip replacement has an acetabular shell 12 within which is placed an acetabular liner 14. The hip replacement also has two components, a femoral prosthesis 16 including a prosthetic femoral head 18 and a prosthetic femoral implant or stem 20 (which in turn includes a prosthetic femoral neck 17).

[0037] Figure 5 shows an exploded view of the replacement hip prosthesis 10 in place within a patient. As shown in Figure 5, the acetabular shell 12 is secured to the pelvic bone 23. The femoral stem 20 is coupled to the femur 24, with the femoral head 18 shown ready to be placed on the femoral stem 20 and into the acetabular shell liner 14. Figures 4 and 5 are discussed together to explain various embodiments.

[0038] A number of sensors 22 are positioned within the prosthesis 10 for in situ or in-situ monitoring of real-time behavior of the patient and prosthesis performance. Various of these sensors will now be described according to various embodiments.

[0039] In one embodiment, contact sensors 22 are provided on the exterior surface of the acetabular shell 12. These sensors 22 detect and record contact between adjacent components, such as between the acetabular shell 12 and the pelvis 23 and / or between the acetabular shell and bone cement (if present) and / or between the bone cement (if present) and the pelvis. The contact sensors 22 can detect loosening of the prosthesis 10 and its connection to the surrounding cement (if present) and / or the pelvic bone. Acetabular loosening is a common complication that occurs when bone loss occurs in the pelvic bone around the acetabulum (typically over 8-12 years) (e.g., due to a process called osteomalacia or osteolysis). Bone erosion around the implant can be caused by friction between the femoral head and the acetabular cup, which can cause material debris (metal, ceramic, and / or polyurethane fragments) to enter the tissue surrounding the implant and cause inflammation and bone loss. Other potential causes of inflammation and bone softening are vibration and movement of the implant, mechanical wear and tear, lack of biocompatibility of the implant material with the surrounding bone, metal allergies, and lack of biocompatibility of the bone cement with the surrounding bone. Additionally, the contact sensor 22 can indicate that it is positioned farther from the pelvic bone 23 than desired as a result of material debris buildup over time and / or the presence of inflammation between the shell and the pelvic bone. Multiple contact sensors 22 are positioned at different locations around the acetabular shell 12. In the illustrated embodiment, multiple sensors are shown positioned on the exterior surface of the acetabular shell 12. In various embodiments, the sensors can be positioned in a variety of patterns based on the location of contact with the pelvic bone and / or the surrounding bone cement (if present). For example, the sensors may be arranged in an X-shaped pattern, as oval or concentric rings around the acetabular shell from the outermost periphery to the crown, or in various other patterns to gather accurate data regarding the physical contact of the acetabular shell 12 with the pelvic bone 23 and / or surrounding bone cement (if present).In various embodiments, contact sensors may also be dispersed and / or arranged within the bone cement (if present) to collect data regarding the physical contact of the bone cement with the acetabular prosthesis and / or the physical contact of the bone cement with the pelvic bone.

[0040] Contact sensors 22 may also be positioned at various locations on the two surfaces of the acetabular liner 14. Thus, the contact sensors 22 can detect contact (and / or relative motion) between the acetabular liner and the acetabular shell (these sensors may be "paired" to detect slippage between the acetabular liner and the shell) as well as contact between the femoral head and the acetabular liner. Similarly, contact sensors 22 may be positioned at various locations on the femoral head to detect contact between the femoral head and the acetabular liner. Thus, in the embodiment of FIGS. 4 and 5, various contact sensors are provided to monitor contact between the bone and the acetabular component and between the femoral head and the acetabular liner. Dislocation of the femoral head from the natural acetabulum or the synthetic acetabulum of an artificial hip joint is a common complication of hip replacements, occurring shortly after surgery (particularly while the surrounding supportive tissues are healing from surgery), and sensors on the femoral head and / or acetabulum can alert the patient and healthcare provider if joint dislocation occurs. Partial or incomplete displacement (subluxation) of the hip joint may also occur, which may not be readily apparent to the patient or physician; contact sensors on the femoral head and acetabulum can determine whether the joint is functioning correctly (tracking) and whether subluxation (even if subclinical or asymptomatic) is occurring.

[0041] Additional contact sensors may also be located on the femoral stem to monitor contact between the femur and / or the surrounding bone cement (if present). Contact sensors may also be distributed and / or arranged within the bone cement (e.g., 22B, if present) to collect data regarding physical contact between the bone cement and the femoral prosthesis and / or the femoral canal. These sensors 22, 22B can detect and record contact between the connecting components within the modular femoral prosthesis, such as the femoral head 18, femoral neck 17, and / or femoral stem 20. These sensors, which may be located in corresponding pairs on adjacent components, can be used to verify that the connecting elements of the modular femoral prosthesis are properly aligned and attached. Sensors on the femoral body 20 can be used to monitor contact between the femoral body and the femur and / or between the femoral body and the surrounding bone cement (if present), and sensors in the bone cement can be used to monitor contact between the femoral body and the bone cement (e.g., 22B, if present) and the femur. Contact sensors on the femoral body 22 can detect loosening of the prosthesis and its connection to the surrounding cement (if present) and / or the femur. Femoral body loosening is a common complication that occurs when bone loss occurs within the femoral canal around the femoral body due to osteolysis (typically over 8-12 years). As mentioned above, bone erosion around the implant can be caused by material debris (metal, ceramic, and / or polyurethane fragments) that arise from friction between the femoral head and the acetabular cup and enter the tissues around the femoral prosthesis, causing inflammation and bone loss. Other potential causes of inflammation and bone softening are implant vibration and movement, mechanical wear and abrasion, lack of biocompatibility of the implant material with the surrounding bone, metal allergies, and lack of biocompatibility of the bone cement with the surrounding bone. Multiple contact sensors 22 are positioned at different locations around the femoral shaft. As shown in Figures 4 and 5, the sensors are shown positioned on the outer surface of the femoral shaft.In various embodiments, the sensors may be arranged in a variety of different patterns based on the location of contact with the femoral canal and / or surrounding bone cement, if present. For example, the sensors may be arranged in a spiral pattern, as vertical lines or concentric rings around the femoral shaft, or in various other patterns to gather accurate data regarding the physical contact of the femoral shaft 20 with the femur and / or surrounding bone cement, if present. In various embodiments of the present invention, the contact sensors are arranged on the femoral shaft and femoral bone and / or bone cement at a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, or greater than 10 sensors per square centimeter or per cubic centimeter of the device.

[0042] FIG. 6A is an exploded view of the acetabular shell 12, liner 14, and femoral head 18 to clearly illustrate various locations for strain gauges 26 that can be placed on the prosthesis. Contact sensors 22, not shown in FIG. 6, can be used simultaneously with the strain gauges, and such contact sensors can be positioned adjacent to each other or can be the same sensor. The strain gauges 26 can be placed at various locations on the acetabular shell 12 to detect stresses between the prosthesis and the anterior bone. A decrease in strain indicates bone resorption (loss), which indicates likely prosthesis loosening or fracture. The strain sensors 26 provide different data points than the contact sensors 22. The contact sensors 22 only indicate whether there is currently contact between adjacent structures and thus provide a good indication of whether abutting contact between two surfaces is occurring. However, these contact sensors do not provide an indication of whether strain is present on any of the surfaces, whereas the strain sensor 26 outputs data representative of the mechanical strain forces being exerted on the entire implant, which, if not corrected, may be a precursor to future loosening and prosthesis failure. Additionally, the strain gauge 26 may be of a type that indicates strain occurring between two surfaces, such as between the acetabular liner and the pelvic bone, or between the acetabular shell 12 and the acetabular liner 14. Furthermore, such a strain gauge may gather data regarding the strain between the femoral head 18 and the acetabular liner 14 and the location of such strain.

[0043] As shown in Figure 6B, strain gauges can be placed on the femoral prosthesis, particularly on the femoral stem, but also on the femoral neck and femoral head. Strain gauges can be positioned at various locations on the femoral stem to detect strains occurring between the prosthesis and the surrounding bone. A decrease in strain indicates bone resorption (loss) within the femoral canal, which likely indicates loosening of the prosthesis or fracture of the femur. Strain sensors provide an indication of strains present in the femoral shaft and can measure the most significant mechanical strain stresses being applied to the entire implant, which, if not corrected, result in loosening and a high probability of prosthesis failure. In various embodiments of the invention, strain sensors are positioned on the acetabular shell, acetabular liner, femoral shaft, and femur and / or bone cement at a density of 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more sensors per square centimeter or per cubic centimeter of the device.

[0044] 7A and 7B illustrate an embodiment in which accelerometers are positioned at various locations in and on the femoral shaft 18, femoral neck, and femoral head. Specifically, as shown in FIG. 7A, one or more accelerometers may be positioned on the femoral head 18. Additionally, one or more acceleration sensors 42 in the form of accelerometers or gyroscopes may be positioned on or within the femoral shaft portion 18. Accelerometers offer the advantage of being able to detect acceleration, vibration, shock, tilt, and rotation of various components, thereby enabling the performance of the prosthesis 10 to be measured under various conditions and over time. In this particular example, the prosthesis 10 is a hip replacement. Of course, it could also be any other prosthesis, such as an artificial elbow, shoulder, metacarpal, talocrural (ankle) joint, etc. In various embodiments of the invention, strain sensors are positioned on the acetabular shell, acetabular liner, femoral shaft, and femur and / or bone cement at a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, or greater than 10 sensors per square centimeter or per cubic centimeter of the device.

[0045] Shortly after the hip replacement, the lower limb is first passively moved, then actively moved, and soon thereafter, the patient begins to progressively bear weight on the joint. The accelerometer 42 will measure the motion of the hip joint space during movement, including walking, as the leg swings forward, strikes the ground, lifts off the ground, and propels the body forward. Additionally, the accelerometer will measure the impact of the foot striking the ground and the force transmitted through the femur to the pelvic bone, as well as any vibration, impulse, or rotation that may occur at different locations within the prosthesis 10. As the patient continues to improve their range of motion postoperatively, accelerations occurring at different locations within the prosthetic hip joint can be monitored. As expected, as the patient heals from surgery, their activity level will gradually improve, their gait will improve, their steps will become more rapid (and fluid), and longer stride lengths will be achieved with each step. This can result in a significant impact whenever the foot strikes the ground, which can be measured over time (and compared to previous values) by various accelerometers 42 located on the femoral head 18, in the femoral stem 20, and elsewhere on the prosthesis 10. Post-operative progress can be monitored (readings can be compared daily, weekly, etc.), and information can be compiled and relayed to both the patient and their physician so that rehabilitation can be followed and compared to expected (typically age-group) norms. In certain embodiments, the wearable device interrogates the sensors in a selected or randomized manner and captures and / or stores the collected sensor data. This data can then be downloaded to another system or device (as described in more detail below).

[0046] By integrating the data collected by the sensors described herein (e.g., contact sensors, strain gauges, and / or accelerometers) with simple, widely available, commercially available analytical techniques, such as pedometers and global positioning system (GPS) capabilities, further clinically relevant data can be gathered, including, but not limited to, the patient's ambulation level (time, distance, steps, speed, cadence), the patient's activity level (activity frequency, duration, intensity), exercise tolerance (work, calories, power, training effect), range of motion (discussed below), and prosthesis performance under various "real-world" conditions. The value of this information in enabling better management of a patient's recovery is difficult to overstate. The treating physician (or physical therapist or rehabilitation specialist) only observes the patient episodically during scheduled visits, and the patient's degree of function at the precise moment of the visit may be affected by many non-correlated factors, such as the presence or absence of pain, the presence or absence of inflammation, stiffness, time of day, compliance and timing of medications (pain medications, anti-inflammatory medications), recent activity and exercise level, the patient's endurance, mood, language barriers, characteristics of the physician-patient relationship, or the patient's ability to accurately describe their symptoms, to name a few. Continuous monitoring and data collection allow patients and physicians to objectively monitor progress by providing information about the patient's function under many conditions and circumstances, thereby enabling them to assess how performance has been affected by various interventions (pain control, exercise, physical therapy, anti-inflammatory medications, respiration, etc.), and to compare rehabilitation progress with prior and future predicted function. Better treatment decisions and better patient compliance are expected when both physicians and patients have the advantage of observing the effects of various treatment modalities on the patient's rehabilitation, activity, function, and overall performance.

[0047] The sensors used for contact, strain sensors and accelerometers may be of any commonly available strain-acceptable type (see, for example, U.S. Pat. Nos. 7,450,332, 7,463,997, and 7,924,267, which describe various types of such sensors, including strain gauges, accelerometers, and MEMS sensors that can act as many other sensing functions). The particular sensor described in U.S. Pat. No. 7,450,332 detects the free fall and movement of an object relative to a gravitational field, and has particular advantages in that it can detect and store all of the forces acting on the lower limb and the entire movement of the lower limb during passive and active movement of the lower limb, as well as when the lower limb swings out between steps, all before, after, and during impact with the ground.

[0048] 7A, 8A, and 8B illustrate yet another type of sensor, namely, an articular surface wear sensor 46, which can be positioned at various locations within the acetabular liner and femoral head. According to one embodiment, one or more articular surface wear sensors are positioned at various depths within the acetabular liner 14 and / or femoral head 18, as shown in FIGS. 7A and 8B. These sensors 46, which measure the degree of surface wear, may be contact pressure sensors embedded at various depths within the acetabular liner and / or femoral head to monitor erosion of the articular surface (and provide information regarding the degree and depth of surface wear of the two components). These sensors may also be positioned between the acetabular shell 12 and acetabular liner 14, as shown in FIGS. 8A and 8B, to monitor any given wear or deterioration of the physical contact between the acetabular shell 12 and acetabular liner 14.

[0049] 9 shows an example of an entire prosthesis in the form of a replacement hip joint provided with multiple different sensors (e.g., 22, 24, 42, 44, 46). The prosthesis may include multiple contact sensors 22, strain gauges 24, accelerometers 42, articular wear surface sensors 46, and electrical power generating structures 44 within a single hip joint prosthesis 10. Additionally, multiple position sensors may also be positioned to monitor, record, and transmit the precise position of the femoral head 18 relative to the acetabular liner 14.

[0050] FIG. 10 illustrates different locations where position sensors 52 and / or accelerometers 53 can be located within a prosthesis. Position sensors 52 and accelerometers 53 can be located both proximally and distally within the femoral stem, femoral neck, or femoral head. These position sensors may also be housed within the acetabular components, i.e., both the acetabular liner and the acetabular shell. By placing position sensors and / or accelerometers along the length of the femoral stem, the exact location of the femur relative to the acetabular component and pelvis can be accurately determined and stored in memory. Similarly, by placing accelerometers at different locations within the neck and head of the femoral implant, the amount of pressure applied at different locations, movement at those locations, and the relative position of the acetabular components relative to one another can be accurately determined. Similarly, such sensors can improve the accuracy of anthropometry and detect complete or partial dislocation (subluxation) of the hip joint.

[0051] C. Coating applied to hip implants Certain embodiments of the present invention provide hip implants that may have one or more coatings applied to one or more surfaces of the hip implant. Coatings may be applied to the hip implant for a variety of purposes. Coatings may be biodegradable, non-biodegradable, or a combination thereof. Representative examples of coatings are those based on polymers (e.g., polymers composed of polyurethane, polyester, polylactic acid, polyamino acid, polytetrafluoroethylene, Teflon®, Gortex®), although non-polymeric coatings may also be utilized. In certain embodiments of the present invention, one or more sensors as described herein may be dispersed throughout the coating (e.g., even in a random manner).

[0052] D. Drug-eluting hip implant In certain embodiments of the present invention, a drug-eluting hip implant is provided that has one or more sensors and can be used to release a desired agent (e.g., a drug or therapeutic agent) to a desired location within the body. Representative examples of suitable anti-scarring or anti-fibrotic agents are disclosed in U.S. Patent No. 5,716,981, U.S. Patent Application Publication Nos. 2005 / 0021126, 2005 / 0171594, 2005 / 0181005, and 2005 / 0181009, the disclosures of which are incorporated by reference in their entireties.

[0053] In related embodiments, a drug-eluting delivery device may be provided within the hip implant to release a desired drug on demand (e.g., remotely activated / on demand or based on a timed schedule, see generally U.S. Patent Application Publication No. 2011 / 0092948, entitled "Remotely Activated Piezoelectric Pump For Delivery of Biological Agents to the Intervertebral Disc and Spine," which is incorporated herein by reference in its entirety) or upon detection of an activation event (e.g., upon detection of a leak via a pressure sensor). For example, in certain embodiments of the present invention, a biological agent may be administered with or released from the hip implant to treat or prevent disease (e.g., i) in the case of cancer, with a chemotherapeutic agent or to prevent restenosis, or ii) in the case of infection, with an antimicrobial agent).

[0054] In a preferred embodiment, one or more sensors (e.g., pressure sensors, contact sensors, and / or position sensors) may be utilized to determine proper placement of the desired agent, as well as the amount and release kinetics of the agent to be released at the desired site.

[0055] E. How to monitor for infection In another embodiment, a hip implant is provided having one or more temperature sensors that can be used to measure the temperature of the hip joint, the temperature of the hip implant, and the temperature of the local tissue and environment adjacent to the hip implant. Also provided is a method for monitoring changes in temperature over time to determine and / or provide notification (e.g., to a patient and / or healthcare provider) of impending infection.

[0056] In certain embodiments of the present invention, metabolic and physical sensors can be used to monitor for rare but potentially life-threatening complications of joint replacement surgery. In a small percentage of patients (less than 1%), the artificial hip joint and surrounding tissues can become infected, typically due to bacteria (often Staphylococcus aureus or Staphylococcus epidermidis) that contaminate the surgical field and colonize the patient's own skin. Sensors such as temperature sensors (detecting increased temperature), pH sensors (detecting decreased pH), and other metabolic sensors can be used to indicate the presence of infection on or around the implant. Early detection of infection allows preemptive treatment with antibiotics or surgical drainage, eliminating the need for artificial removal of the prosthesis.

[0057] F. Power generation FIG. 7B illustrates a particular advantage that can be gained when a patient is walking with a new hip prosthesis. As shown in FIG. 7B, a small electrical generating unit 44 can be placed along the outer surface of the femoral stem 18, or alternatively, along the inner surface. Specifically, each time the user takes a step, a pressure release and buildup occurs within the internal structure of the femoral stem 16. Using a suitable piezoelectric material or a micro-electrical generator, a small amount of electricity can be generated with each step. This electricity can be stored in a capacitor also located within the femoral stem 16. This electricity can then be used to power sensors located at various locations within the prosthesis.

[0058] Various techniques for extracting electrical power from slight mechanical motion or vibration have been described. See, for example, UK Singh et al., "Piezoelectric Power Scavenging of Mechanical Vibration Energy," Australian Mining Technology Conference, October 24, 2007, pp. 111-118. This paper provides examples of various types of power scavengers that can generate electricity from extremely slight motion and store this electricity for later use. The paper also describes embodiments in which pressure is applied and extracted from a particular structure to generate electricity as a result of the application of high pressure, eliminating the need for motion. As described in the embodiments herein, when a patient takes a step and puts their weight on their leg, a force is applied to the internal structure of the femoral stem 16, which can generate more than enough power to power all of the sensors described herein. Another mechanism capable of generating electricity from very small amounts of repetitive motion is described in U.S. Patent Application Publication No. 2010 / 0164705, published July 1, 2010. This U.S. patent application describes the fact that energy can be extracted during tire rotation, which can then be used to power multiple different sensors, which can then output collected data to a central collection location over selected time periods. Another sensor of this type is described in issued U.S. Patent No. 7,603,894, entitled "Self-Powered Tire Monitoring System."

[0059] In a preferred embodiment, the electrical generation system does not move, relying only on the pressure applied during a step and the release of that pressure as the step is completed and the leg is free to swing out for the next step. Because no movement occurs, the patient does not experience any sensation due to slight changes in the position or length of the femoral stem 18 during a step. Instead, the length is held constant and the electricity is generated by a piezoelectric structure or an internal suspension structure that is not part of the support structure of the femoral stem 18.

[0060] Other techniques are also available for harvesting power, such as those disclosed in Chandrakasan et al., "Next Generation Micro-power Systems," Symposium on VLSI Circuits Digest of Technical Papers, 2008, pp. 1-5 (see also U.S. Pat. No. 8,283,793, entitled "Device for Energy Harvesting within a Vessel," and U.S. Pat. No. 8,331,632, entitled "Devices, Methods and Systems for Harvesting Energy in the Body"). All of these patent and non-patent documents are incorporated herein by reference in their entirety.

[0061] After electricity is generated by one or more electrical generators 44, it is transmitted to any one of the various sensors described herein. For example, the electricity can be transmitted to the contact sensor 22, the strain gauge 24, or the accelerometer 42. The electricity can also be transmitted to other sensors described later in this specification. The transmission of power can be accomplished by any acceptable technique. For example, if the sensor is physically coupled to the femoral stem, an electrical wire can run from the electrical generator 44 to the particular sensor, such as the accelerometer 42 or other surface wear structure that is part of the femoral stem. For sensors located within the acetabular component, the electricity can be transmitted wirelessly in the same manner that a wireless smart card receives power from a nearby power source using appropriate transmit and receive antennas. Such power transmission and reception techniques are also described in the publications, published patent applications, and issued U.S. patents referenced above, all of which are incorporated herein by reference.

[0062] G. Medical Use of Sensors 11A and 11B show examples of sensor use during a patient's anthropometry and various types of data that can be obtained from sensors implanted in accordance with the teachings herein. The sensors provide assessment data regarding the range of motion (ROM) of the prosthetic hip joint. Currently, ROM is typically measured clinically by a physician passively moving the prosthetic hip joint through its entire range of motion during anthropometry and recording the results (degree of flexion, extension, abduction, adduction, external rotation, internal rotation, and rotation during flexion). Motion sensors and accelerometers can be used to accurately determine the total ROM of the prosthetic hip joint both during anthropometry and during normal daily activities between visits. As shown in FIG. 11A, one key factor in hip joint health is the angle X that the patient can achieve at various points during physical therapy as the patient recovers from surgery. As angle X decreases, physicians can be more confident that the joint's function is improving. By tracking angle X over time, a physical therapist can monitor a patient's progress, assess whether scar tissue formation, subluxation, or other pathological features are limiting / impacting hip ROM, and modify / implement treatment as needed. With the sensor attached as instructed herein, the physical therapist or physician does not need to assume that the angle has been achieved; instead, when the lower extremity is placed adjacent to the readout computer, the exact angle can be known right at the time the hip joint is being clinically evaluated. On the other hand, if X continues to not decrease but remains large (or even increases), the physical therapist or physician may be alerted to problems the patient may be having with rehabilitation or delayed recovery from surgery, and can investigate and / or take action sooner rather than later. Similarly, the embodiment of FIG. 11B indicates measurements that can be taken when the user is holding the lower extremity at exactly the 90° angle Y as shown. With the leg held firmly at a 90° angle, data can be collected from various sensors on the entire leg to obtain strain, contact location, acceleration and other data.A sensor used in the present invention can remind the patient that the leg is held at exactly 90°, allowing data collection to be accurate when the patient is monitored and data is collected at different times over several months. While flexion and extension are shown in the diagrams, it should be clear to one skilled in the art that data can also be collected for abduction, adduction, external rotation, internal rotation, and rotation during flexion. Additionally, ROM can also be monitored between patient visits by interpreting the ROM occurring during daily activities when the patient is at home.

[0063] Several aspects of operation and the benefits they provide are now described. One particular advantage is the patient's recovery and live, in-situ monitoring of the hip implant 10. The sensors described herein collect data in a consistent manner during normal daily activities, and even overnight if necessary. That is, strain is measured, collected, and stored periodically over an extended period of time, and certain measurements are taken periodically. For example, a contact sensor may acquire and report data once every 10 seconds, once a minute, or once a day. Other sensors may collect data more frequently, for example, several times a second. For example, acceleration and position data are likely to be collected and stored several times a second. Other types of data may only need to be collected on a minute-by-minute or hourly basis. Because femoral stems in the prior art have large inner sections or solid bars of metal that are hollow, this internal structure has more than enough space to accommodate one or more processor circuits, CPUs, memory chips, and other electronic circuits, as well as antennas for transmitting and receiving data. The processor can be programmed to collect data from the various sensors on any desired schedule set by the medical professional. All procedures can be continuously monitored post-operatively, and data can be collected and stored in memory located within the femoral stem 18.

[0064] Patients typically undergo periodic health checkups. When the patient visits a physician's office for a checkup, the physician places a reader in close proximity to the implant 10, in this example, a hip replacement, to transfer data from the internal circuitry within the femoral stem 18 to a database within the physician's office. The use of wireless transmission using smart cards or other technologies is extremely well known in the art and need not be described in detail. Examples of such wireless data transmission are described in the U.S. patent applications and patents mentioned herein. Data collected based on the patient's exercise and use of the lower limb over the preceding weeks or even months is transferred from memory located within the femoral stem 18 to the physician's computer or wireless device over the next few months. The computer then analyzes the data for abnormalities, unexpected changes over time, positive or negative trends, and other indications of the patient's health and the functionality of the prosthesis. Additionally, the physician can collect data detailing a record of all impacts on the hip joint, including the magnitude and direction of accelerations. If the physician locates a high acceleration event, such as a patient fall or other physical activity or movement, the physician can be alerted to inquire with the patient about any issues the patient had at the time of the fall, or alternatively, warn the patient against overly vigorous activity that could potentially cause damage to the hip implant. For example, if the patient decides to go skiing or jogging, the physician can monitor the effects of such activity on the implant 10, including the accelerations and strains during the event itself. The physician can then examine the health of the prosthesis in the hours and days following the event and compare this to data prior to the event, thereby determining whether any particular event caused long-term damage, i.e., separation of the prosthesis from the surrounding bone tissue or joint subluxation, or whether the activity subjected the implant to stresses / strains / impact forces that exceed the manufacturer's performance specifications for that particular hip prosthesis.Data can be collected and compared to the current and long-term performance of the implant from strain gauges, contact sensors, surface wear sensors, or other sensors that may be present.

[0065] In one variation, patients may also have such a reading device at home, which periodically collates data from the implant, e.g., once a day or once a week. Empowering patients to pursue their own rehabilitation—and allowing them to recognize the positive (and negative) effects of various lifestyle choices on their health and rehabilitation—can be expected to improve compliance and patient outcomes. Furthermore, patients' experiences can be shared with other patients via the Web, allowing them to compare their progress with expected "norms" for function and rehabilitation and alert them to signs and symptoms that should be brought to the attention of their physicians. The performance of different implants can be compared in different patients (e.g., different genders, weights, activity levels), thereby helping manufacturers design better prostheses and helping orthopedic surgeons select the correct prosthesis for a particular patient type. Payers, patients, manufacturers, and physicians can all benefit from the collection of this comparative information. Finally, data collected at home can be collected and transmitted via the internet to a doctor's office for analysis—potentially eliminating unnecessary visits and potentially facilitating prompt medical follow-up.

[0066] H. Medical imaging and self-diagnosis, predictive analysis and predictive maintenance of assemblies including hip implants The present invention provides a hip implant that can be imaged through the use of sensors over a variety of conditions. For example, according to various aspects of the present invention, a method of imaging an assembly including a hip implant or hip replacement with sensors is provided, the method including detecting changes in sensors in, on, and / or within the hip implant over time, the hip implant having a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, greater than 10, or greater than 20 sensors per square centimeter. In other aspects, the hip implant has a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, greater than 10, or greater than 20 sensors per cubic centimeter. In any of these embodiments, there may be fewer than 50, fewer than 75, fewer than 100, or 100 sensors per square centimeter or cubic centimeter. As mentioned above, a variety of sensors can be utilized in the present invention, including, for example, contact sensors, strain gauge sensors, pressure sensors, fluid pressure sensors, position sensors, pulse pressure sensors, blood volume sensors, blood flow sensors, blood chemistry sensors, blood metabolism sensors, mechanical stress sensors, and temperature sensors.

[0067] For example, using a hip implant with sensors described herein, the hip joint anatomy can be imaged with sensors capable of detecting positional motion. The sensors used may further include an accelerometer and a motion sensor to detect hip joint implant motion due to various physical changes. Changes in the position of the accelerometer and / or motion sensor over time can be used as a measure of changes in the position of the hip joint implant over time. Such positional changes can be used as surrogate markers of the hip joint anatomy—i.e., they can generate an “image” of the hip joint implant to provide information regarding changes in size, shape, and location of the hip joint implant and / or movement / translation of the hip joint implant. For example, loosening of the hip joint implant (typically within the femoral stem or acetabular shell) can result in undesired movement of the prosthesis relative to the weight-bearing bone in which it is implanted during activity. By utilizing sensors in the present invention, the location and magnitude of undesired motion present during different movements and activities can be determined. Similarly, monitoring changes in the joint space (i.e., changes in the space separating the femur and acetabular component) over time can be used as an indicator of erosion and wear of the articular surfaces (femoral head and / or acetabular liner). Finally, following the movement of the sensor through the joint's range of motion can provide a dynamic "picture" (video) of the joint, allowing the physician to monitor both the improvement and progression of joint function (and surrounding tissues) over time.

[0068] Certain exemplary embodiments will now be described in detail. One particular advantage is live, in situ monitoring of a patient's recovery with a hip implant. The sensors described herein collect data on a regular basis, during normal daily activities, and even overnight if necessary. For example, a contact sensor may acquire and report data once every 10 seconds, once a minute, or once a day. Other sensors will collect data more frequently, for example, several times a second. For example, it is expected that temperature, contact, and / or position data will be collected and stored several times a second. Other types of data only need to be collected on a minute-by-minute or hourly basis. Still other sensors may collect data only when signaled by the patient as part of an "event record" - i.e., when the patient experiences a particular event (e.g., pain, trauma, etc.) - and may send a signal to an instrument to obtain a reading at that time (by an external signal generating / triggering device), the purpose of which is to allow comparison of subjective / symptomatic data with subjective / sensor data in an attempt to better understand the underlying cause or trigger of the patient's symptoms.

[0069] In certain cases, the hip implant is of sufficient size and has more than enough space to accommodate one or more processor circuits, CPUs, memory chips, and other electrical circuits, as well as antennas for transmitting and receiving data. In other embodiments, the associated medical instrument may accommodate one or more processor circuits, CPUs, memory chips, and other electrical circuits, as well as antennas for transmitting and receiving data. The processor can be programmed to collect data from various sensors on any desired schedule set by the medical professional. All procedures can be continuously monitored postoperatively, and data can be collected and stored in memory located within the hip implant.

[0070] Patients with hip implants typically undergo periodic health checkups. When the patient visits a doctor's office for a checkup, the doctor places a reader in close proximity to the implant, in this example, the hip implant, to transfer data from the internal circuitry within the hip implant to a database within the doctor's office. The use of wireless transmission using smart cards or other technologies is quite well known in the art and need not be described in detail. Examples of such wireless transmission of data are described in the U.S. patent applications and patents mentioned herein. Collected data (e.g., collected over a short period of time, over weeks, or even over several months) is transferred from a memory located within the hip implant to the doctor's computer or wireless device in several months. The computer then analyzes the data for abnormalities, unexpected changes over time, positive or negative trends, and other indications of the patient's health and the functionality of the hip implant. For example, if the patient decides to go skiing or jogging, the doctor can monitor the effects of such activity on the hip implant, including accelerations and strains during the event itself. The physician can then examine the health of the hip implant in the hours and days following the event and compare this to data prior to the event to determine whether any particular event caused long-term damage or whether activity subjected the hip implant to forces that exceed the manufacturer's performance specifications for that particular hip implant. Data can be collected and compared to the current and long-term performance of the hip implant from strain gauges, contact sensors, surface wear sensors, or other sensors that may be present. A representative example of an Electronic Data Capture, Documentation, and Clinical Decision Support System (EDDS) is described in WO 2012 / 061825, which is incorporated by reference in its entirety.

[0071] In one variation, patients may also have such a reading device at home, which periodically collates data from the implant, e.g., once a day or once a week. As mentioned above, patients may also "trigger" device readings (via an external signal-generating / triggering device) as part of an "event log." Empowering patients to pursue their own rehabilitation—and allowing them to recognize the positive (and negative) effects of various lifestyle choices on their health and rehabilitation—can be expected to improve compliance and patient outcomes. Furthermore, patients' experiences can be shared with other patients via the Web, allowing them to compare their progress with expected "norms" for function and rehabilitation and alert them to signs and symptoms that should be brought to the attention of their physicians. The performance of different hip implants can be compared in different patients (e.g., different genders, weights, activity levels), thereby helping manufacturers design better devices and assisting surgeons and other healthcare providers in selecting the right hip implant for a particular patient type. Payers, patients, manufacturers, and physicians can all benefit from the collection of this comparative information. Finally, data collected at home can be collected and transmitted via the internet to a doctor's office for analysis—potentially eliminating unnecessary visits and potentially facilitating prompt medical follow-up.

[0072] I. How to monitor hip implants As mentioned above, the present invention also provides a method for monitoring one or more of the hip implants provided herein. FIG. 12 illustrates a monitoring system that can be used with a hip implant 10, for example, of the type shown in any one of the above-described figures. The monitoring system includes sensors (e.g., 22, 22B, 24, 42, and / or 46), an interrogation module 124, and a control unit 126. The sensors (e.g., 22, 22B, 24, 42, and / or 46) are of a passive wireless type that can operate with power received from a wireless source. Such sensors are well known and widely available in the art. This type of pressure sensor can be a MEMS pressure sensor, such as part number LPS331AP, available on the open market from STMicroelectronics. MEMS pressure sensors are well known to operate with very little power and are suitable for remaining unpowered and idle for long periods of time. These pressure sensors can be wirelessly powered by an RF signal, and based on the power received wirelessly over the RF signal, these pressure sensors detect pressure and then output the detected data.

[0073] In one embodiment, an electrical generation system (described above) is provided that can be utilized to power the sensors described herein. In operation, as shown in FIG. 12 , interrogation module 124 outputs signal 128. Signal 128 is a wireless signal, typically in the RF band, that includes power for the sensor (e.g., 22, 22B, 24, 42, and / or 46) and an interrogation request for sensor 22 to perform sensing. Upon interrogation by signal 128, the sensor (e.g., 22, 22B, 24, 42, and / or 46) wakes up and stores sufficient power in an on-board capacitor to maintain operation during sensing and data reporting. Such power receiving circuitry and power storage in on-board capacitors are well known in the art and therefore need not be described in detail. Appropriate detection is performed by a sensor (e.g., 22, 22B, 24, 42 and / or 46), and data is then output from the sensor and returned in the form of a signal 130 to the interrogation module 124, where the signal 130 is received at an input port of the interrogation module.

[0074] According to one embodiment, sufficient signal strength is provided in the initial signal 128 to power the sensor, perform detection operations, and output a signal back to the interrogation module 124. In other embodiments, two or more signals 128 are sent, each providing sufficient power to the sensor to complete detection operations and then transmit data over signal path 130 back to the interrogation module 124. For example, the signal 128 can be sent continuously with a detection request component in a first portion of the signal, followed by subsequent power to operate the sensor, either as a steady signal or as a pulse. When the sensor is ready to output data, it can send a warning signal to the interrogation module 124 that data is coming and turn off the signal 128 to avoid interference. Alternatively, the interrogation signal 128 can be at a first frequency and the output signal 130 can be at a second frequency that is sufficiently separated so that the signals 128, 130 do not interfere with each other. In a preferred embodiment, both of these signals are at the same frequency so that the same antenna on the sensor can receive signal 128 and transmit signal 130 .

[0075] The interrogation signal 128 may include data for selecting a particular signal on the hip replacement. For example, the signal 128 may activate all sensors on the hip replacement simultaneously, then send a request for data from each at different selected times, so that one interrogation signal 128 is provided for a set period of time, e.g., 1-2 seconds, so that each of the sensors on the hip replacement collects data during this period, and then at the end of the period, reports the data at different times over the next 0.5-2 seconds on respective signals 130, so that data from all sensors 22 is collected with one interrogation signal 128.

[0076] The interrogation module 124 operates under the control of a control unit 126, which includes a microprocessor for the controller, memory, I / O circuitry for interfacing with the interrogation module, and a power supply, which outputs data to a computer or other device for display and use by a physician to treat the patient.

[0077] FIG. 13 illustrates operation of a preferred embodiment within a patient's body. The patient has an epidermis 132. As shown in FIG. 13, the interrogation module 124 and control unit 126 are positioned external to the patient's skin 132. An interrogation signal 128 passes through the patient's skin as a wireless RF signal, and data is received on a wireless RF signal 130 from the sensors (e.g., 22, 22B, 24, 42, and / or 46) and returned to the interrogation module 124. The wireless signal can be in any frequency range, but the RF range is preferred. Frequencies in the VLF-LF range of 3-1300 kHz are preferred to allow the signal to travel deep enough into the body with low power, although frequencies below 3 kHz and above 1300 kHz can also be used. Detection does not require the transfer of large amounts of data and low power is preferred, so a low-frequency RF signal is preferable. This also avoids conflicts with and accidental activation by other wireless signal generators, such as Bluetooth, cell phones, etc.

[0078] J. Collection, transfer, analysis, and distribution of data from hip implants FIG. 14 illustrates one embodiment of an information and communications technology (ICT) system 800 configured to process sensor data (e.g., data from sensors (e.g., 22, 22B, 24, 42, and / or 46) of any one of the figures provided herein). In FIG. 14, ICT system 800 is shown as including computing devices that communicate over network 804; however, in other embodiments, the computing devices may communicate directly with each other or through other intervening devices, and in some cases, the computing devices may not communicate at all. The computing device of FIG. 14 includes a computing server 802, a control unit 126, a query unit 124, and other devices not shown for clarity.

[0079] 14 , one or more sensors (e.g., 22, 22B, 24, 42, and / or 46) communicate with an interrogation module 124. In some cases, the interrogation module 124 is directed by a control unit 126, while in other cases the interrogation module 124 operates autonomously to provide and receive information from the sensors 22. One or both of the interrogation module 124 and the control unit 126 may be in communication with a computing server 802.

[0080] In certain embodiments, the interrogation module and / or control unit may be a wearable device attached to the patient. The wearable device (e.g., a watch-like device, a wristband, glasses, or other device portable or wearable by the patient) may interrogate the sensors for set (or random) periods to collect data and transmit the data to one or more networks (804). Additionally, the wearable device may autonomously collect data that may also be transmitted to a network. Representative examples of data that may be collected include location (e.g., GPS), body or skin temperature, and other physiological data (e.g., pulse rate). In yet another embodiment, the wearable device may directly notify the patient of any of a number of predetermined conditions, including, but not limited to, threatened or actual equipment failure.

[0081] The information communicated between interrogation module 124 and sensors (e.g., 22, 22B, 24, 42, and / or 46) may be useful for many purposes described herein. In some cases, for example, sensor data information may be collected and analyzed explicitly for an individual patient's health. In other cases, sensor data may be collected and transmitted to another computing device for aggregation with other data (e.g., sensor data from sensor 22 may be collected and aggregated with other data collected from a wearable device (e.g., which in certain embodiments may include GPS data, etc.)).

[0082] 14 illustrates the perspective of computing server 802 as a collaboration of servers that further includes computing servers 802a, 802b, and one or more other servers 802n. As will be appreciated, computing server 802 may include any number of computing servers that operate individually or collectively for the benefit of users of the computing servers.

[0083] In some embodiments, computing server 802 is configured as a cloud computing service hosted in one or more geographic locations, such as the United States and Canada. The computing service may be hosted as a Microsoft Azure cloud computing service or some other virtually accessible remote computing service.

[0084] The interrogation module 124 and the control unit 126 are shown as optionally in communication with the computing server 802. Via the interrogation module 124 or the control unit 126, the sensor data is transferred over the network 804 to (and additionally or alternatively from) the computing server 802.

[0085] Network 804 may include some or all of a cellular communications network, a conventional cable network, a satellite network, an optical fiber network, and one or more local area networks, wide area networks, personal area networks, etc. configured as a computing network. In a preferred embodiment, network 804 includes any communications hardware and software that cooperate to enable users of computing devices to view and interact with other computing devices.

[0086] The computing server 802 includes a central processing unit (CPU), a digital signal processing unit (DSP) 808, a communications module 810, an input / output (I / O) module 812, and a storage module 814. The components of the computing server 802 are cooperatively coupled to one another by one or more buses 816, which facilitate the transfer and control of information within and through the computing server 802. The communications module 810 can be configured to communicate information between the computing server 802 and other computing devices (e.g., computing servers 802a, 802b, 802n, the control unit 126, the interrogation unit 124, etc.). The I / O module 812 can be configured to receive input from devices such as a keyboard, a computer mouse, a trackball, etc. The I / O module 812 can be configured to provide output to devices such as a display, a recorder, an LED, an audio device, etc.

[0087] The storage module 814 may include one or more types of storage media. For example, the storage module 814 of Figure 14 includes a read-write memory (RAM) 818, a read-only memory (ROM) 810, a disk-based memory 822, an optical memory 824, and other types of memory storage media 826. In some embodiments, one or more database structures are configured on one or more of the storage devices in the storage module 814. The database structures may be used to store data collected from the sensors 22.

[0088] In some embodiments, the storage module 814 may further include one or more portions of memory organized as a non-transitory computer-readable medium (CRM). The CRM is configured to store computer computational instructions executable by the CPU 808. The computer computational instructions may be stored as one or more files, each of which may include one or more computer programs. The computer programs may be stand-alone programs or part of a larger computer program. Alternatively or additionally, each file may include data or other computer computational support material for an application that directs the collection, analysis, processing, and / or distribution of data from sensors (e.g., sensors in a hip replacement). A sensor data application typically executes a set of instructions stored on a computer-readable medium.

[0089] It should be understood that the computing server shown and described herein is exemplary only and does not limit the scope of the present invention. Computing server 802 may be connected to other devices, not shown, including via one or more networks, such as the Internet or via the Web integrated into network 804. Generally speaking, a computing system or device (e.g., a "client" or "server"), or any portion thereof, may include any combination of hardware, optionally programmed or otherwise configured with software, capable of interacting with each other to perform functions of the type described, including, but not limited to, desktop or other types of computers, database servers, network storage devices and other network devices, PDAs, cellular phones, wireless phones, pagers, electronic organizers, Internet appliances, television-based systems (e.g., set-top boxes and / or personal / digital video recorders), and various other products that include appropriate local area communication capabilities. Additionally, the functionality provided by the illustrated system modules may in some embodiments be combined into fewer modules or distributed among additional modules. Similarly, in some embodiments, the functionality of some of the illustrated modules may not be provided and / or other additional functionality may be available.

[0090] Additionally, while various items are shown as being stored in memory or as being stored while in use, these items, or portions of these items, may be transferred between memory and other storage devices for purposes of memory management and / or data integrity. In at least some embodiments, the illustrated modules and / or systems are software modules / systems that include software instructions that, when executed by a CPU / DSP 808 or other processor, program the processor to automatically perform the described operations for the module / system. Alternatively, in other embodiments, some or all of the software modules and / or systems may operate in memory located on another device and communicate information with the illustrated computing system / device via intercomputer communications.

[0091] Furthermore, in some embodiments, some or all of the modules and / or systems may be implemented or provided in other ways, for example, at least partially in firmware and / or hardware means, including, but not limited to, one or more application specific integrated circuits (ASICs), standard integrated circuits, controllers (e.g., by executing appropriate instructions, and including microcontrollers and embedded controllers), field programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), etc. Some or all of the systems, modules, or data structures may also be stored (e.g., as software instructions or structured data) on a transient or non-transitory computer-readable storage medium 814, such as a hard disk 822 or flash drive or other non-volatile storage device 826, volatile memory 818, non-volatile memory 810, network storage, or portable media article (e.g., DVD disk, CD disk, optical disk, flash memory device, etc.), to be read by an appropriate input or output system or via a suitable connection scheme. The systems, modules, and data structures may also, in some embodiments, be transmitted as generated data signals (e.g., as carrier waves or other analog or digital propagated signals) over various computer-readable transmission media, including wireless and wired / cabled media. The data signals may take various forms, such as part of a single or multiplexed analog signal, as multiple separate signal packets or frames, as separate or streaming sets of digital bits, or some other form. Such computer program products may take other forms in other embodiments. Accordingly, the present invention may be practiced with other computer system configurations.

[0092] 14, for example, sensor data from sensors (e.g., 22, 22B, 24, 42, and / or 46) is provided to computing server 802. Generally speaking, the sensor data represents data retrieved from a known patient and a known sensor. The sensor data may include or further be associated with additional information, such as a USI, UDI, timestamp, location (e.g., GPS) stamp, date stamp, and other information. The differences between various sensors are that some may include more or fewer data bits that associate the data with a particular source, collection device, transmission characteristics, etc.

[0093] In some embodiments, sensor data may include sensitive or delicate information, such as private health information associated with a particular patient. Sensitive information, such as sensor data from sensors (e.g., 22, 22B, 24, 42, and / or 46), may include any information that a party desires not to be widely or easily disclosed. Sensitive information may stand alone or may be combined with other, non-sensitive information. For example, patient medical information is typically sensitive information. In some cases, the storage and transmission of patient medical information is protected by government mandates (e.g., laws, regulations, etc.), such as the Health Insurance Portability and Accountability Act (HIPPA) in the United States.

[0094] As used herein, "sensitive" information includes information that is entirely sensitive and information that is any combination of sensitive and non-sensitive information. Sensitive information may be represented in a data file or in some other format. As used herein, a data file containing a patient's medical information may be referred to as "sensitive information." Other information, such as employment information, financial status, identification information, and many other types of information, may also be considered sensitive information.

[0095] A computing system may represent sensitive information through a coding algorithm (e.g., ASCII), a well-recognized file format (e.g., PDF), or some other format, where sensitive information can be protected from wide or easy disclosure by an encryption algorithm.

[0096] Generally speaking, sensitive information can be stored by a computing system as a discrete set of data bits. A set of data bits is sometimes referred to as "plaintext." Furthermore, a computing system can employ an encryption process to convert the plaintext into a set of data bits having a highly unreadable state (i.e., cipher text) using an encryption algorithm (i.e., a cipher). A computing system with knowledge of the encryption key used to create the cipher text can restore this information to its plaintext, readable state. Thus, in some cases, sensitive data (e.g., sensor data 806a, 806b) is optionally encrypted before being communicated to a computing device.

[0097] In one embodiment, the operation of the information and communications technology (ICT) system 800 of Figure 14 includes one or more sensor data computer programs stored on a computer-readable medium. The computer programs can optionally derive and / or receive data from one or more hip replacement sensors implanted within one or more patients. The sensor data computer programs can be executed within the computing server 802. Alternatively or additionally, the sensor data computer programs can be executed within the control unit 126, the interrogation unit 124.

[0098] In one embodiment, a computer program directing the collection and use of hip replacement sensor data is stored on a non-transitory computer readable medium in the storage module 814. The computer program is configured to identify a patient in whom a wireless hip replacement has been inserted. The wireless hip replacement may include one or more wireless sensors.

[0099] In some cases, the computer program identifies one patient, and in other cases, two or more patients are identified, each having one or more wireless hip replacements, each having one or more wireless sensors of the type described herein.

[0100] A computer program is configured to command the collection of sensor data from the wireless hip replacement device. The sensor data is typically collected by a wireless interrogation unit 124. In some cases, the program communicates with the wireless interrogation unit 124. In other cases, the program communicates with a control unit 126, which issues commands to the wireless interrogation unit 124. In still other cases, other mechanisms for commanding the collection of sensor data are used.

[0101] Once the sensor data is collected, it may be further processed. For example, in some cases, the sensor data may include sensitive patient data that may be deleted or disassociated from such data. The sensor data may be stored individually (e.g., by unique sensor identification number, device number, etc.) or may be aggregated with other sensor data by sensor type, timestamp, location stamp, date stamp, patient type, other patient characteristics, or some other means.

[0102] The following pseudo-code description is executed by the computing server 802 and is used to generally describe one example algorithm generally described herein with reference to FIG. TIFF0007722944000001.tif80143

[0103] Those skilled in the art will recognize that it is common practice in the art to embody devices and / or processes and / or systems and then incorporate such embodying devices and / or processes and / or systems into more comprehensive devices and / or processes and / or systems using techniques and / or other practices, i.e., at least portions of the devices and / or processes and / or systems described herein can be incorporated into other devices and / or processes and / or systems with a reasonable amount of experimentation. As will be appreciated by those skilled in the art, examples of such other devices and / or processes and / or systems may include, as appropriate for the context and application, all or part of: (a) air vehicles (e.g., airplanes, rockets, helicopters, etc.); (b) ground vehicles (e.g., automobiles, trucks, locomotives, tanks, armored personnel carriers, etc.); (c) buildings (e.g., homes, warehouses, offices, etc.); (d) appliances (e.g., refrigerators, washers, dryers, etc.); (e) communications systems (e.g., networked systems, telephone systems, voice over IP systems, etc.); (f) businesses (e.g., Internet Service Provider (ISP) businesses, e.g., Comcast Cable, Qwest, Southwestern Bell, etc.); or (g) wired / wireless service entities (e.g., Sprint, Cingular, Nextel, etc.).

[0104] In certain cases, use of a system or method may occur within a jurisdiction even if components are located outside the jurisdiction. For example, in a distributed computing context, use of a distributed computing system may occur within a jurisdiction even if parts of the system (e.g., relays, servers, processors, signal-bearing media, sending computers, receiving computers, etc., that are located outside the jurisdiction) are located outside the jurisdiction.

[0105] Similarly, the sale of a system or method may occur in a jurisdiction even if components of the system or method are located and / or used outside the jurisdiction. Furthermore, the instantiation of at least a portion of a system that performs a method in one jurisdiction does not preclude use of the system in another jurisdiction.

[0106] In conclusion, hip replacements utilizing various sensors can be used to assist in a variety of important clinical functions, such as safe, accurate, and minimally traumatic placement and deployment of the hip replacement, procedural and postoperative (real-time) imaging of the hip replacement and its anterior anatomy, the occurrence of hip replacement complications, and the overall health of the patient. Currently, postoperative evaluation (both inpatient and outpatient) of patients with hip replacements relies on medical monitoring supplemented with patient history, anthropometry, and diagnostic imaging studies as needed. However, the majority of a patient's recovery period occurs between hospital and clinic visits, and much of the data regarding daily function is uncaptured. Furthermore, monitoring a patient's progress using any diagnostic imaging technology can be expensive and invasive, and may carry its own health risks (e.g., coronary angiography). Therefore, accurately measuring and following the onset or worsening of symptoms and assessing hip replacement performance in "real life" can be extremely difficult. This is especially true because symptoms are related to the patient's activity level, exercise tolerance, and the effectiveness of rehabilitation efforts and medications.

[0107] Currently, neither physicians nor patients have access to any form of "real-time," continuous, objective measurement of hip replacement performance that they might otherwise desire. The ability to monitor the function, health, anatomical, and physiological characteristics of the hip replacement in situ can provide useful objective information to the physician during office visits, and the patient can obtain additional readings at home at various times (e.g., when experiencing pain, during exercise, after taking medication, etc.) to provide important complementary clinical information to the physician (which can be sent electronically to a healthcare provider, even from a remote location). From a patient's perspective, the ability to monitor many of these same parameters at home can allow them to play a more preventative role in the patient's care and recovery and can provide the patient with either an early warning indicator or a warrant to seek medical assistance.

[0108] In one variation, the patient may also have such a reading device at home, which periodically collates data from the hip replacement, e.g., once a day or once a week. In addition to empowering patients to pursue their own rehabilitation—and allowing them to recognize the positive (and negative) effects of various lifestyle choices on their health and rehabilitation—such information access is expected to improve compliance and patient outcomes. For example, in certain embodiments, the devices and systems provided herein can inform or otherwise notify the patient or an authorized third party of deviations (e.g., greater than 10%, 20%, 25%, 50%, 70%, and / or 100%) from normal and / or set parameters. Furthermore, a patient's recovery experience can be shared with other patients via the web, thereby comparing their progress with expected "norms" for function and rehabilitation and alerting the patient to signs and symptoms that should be brought to the attention of their physician. The performance of different hip replacements can be compared in different patients (with different genders, weights, activity levels, and comorbidities such as hypertension, diabetes, smoking status, obesity, etc.), thereby helping manufacturers design better hip replacements and assisting physicians in selecting the appropriate hip replacement for a particular patient type. Payers, patients, manufacturers, and physicians can all benefit from the collection of this comparative information. Adulterated or unsafe products can be identified and removed from the market, and objective, long-term valid data can be collected and analyzed. Finally, data collected at home can be collected and transmitted via the Internet to physician offices for analysis—potentially eliminating unnecessary visits and facilitating prompt medical follow-up.

[0109] Below are some specific numbered embodiments of the systems and methods disclosed herein. These embodiments are exemplary only. It is understood that the present invention is not limited to the embodiments set forth herein for purposes of illustration, but includes all such forms of the invention that fall within the scope of the above disclosure. [Embodiment 1] 1. A replacement hip joint prosthesis, comprising: an artificial femoral stem; an artificial femoral head coupled to the femoral stem; A replacement hip prosthesis having an acetabulum prosthesis assembly coupled to the femoral head, and a plurality of sensors coupled to at least one of the femoral stem, the femoral head, and the acetabulum assembly. [Embodiment 2] 2. The artificial hip joint replacement according to claim 1, wherein said plurality of sensors includes a sensor mounted on said femoral stem. [Embodiment 3] 2. The replacement hip prosthesis of claim 1, wherein the plurality of sensors includes a sensor mounted on the femoral head. [Embodiment 4] 2. The replacement hip prosthesis of claim 1, wherein the plurality of sensors includes a sensor provided in the acetabulum assembly. [Embodiment 5] The replacement hip prosthesis according to any one of embodiments 1 to 4, wherein the sensor is selected from the group consisting of an accelerometer, a pressure sensor, a contact sensor, a position sensor, a chemical microsensor, a tissue metabolism sensor, a mechanical stress sensor, and a temperature sensor. [Embodiment 6] 6. The replacement hip prosthesis of embodiment 5, wherein the accelerometer detects acceleration, tilt, vibration, shock and / or rotation. [Embodiment 7] 2. The replacement hip prosthesis of embodiment 1, wherein the plurality of sensors includes a contact sensor disposed between the femoral head and the acetabulum assembly. [Embodiment 8] 2. The replacement hip prosthesis of embodiment 1, wherein the plurality of sensors includes a plurality of contact sensors disposed on an outer surface of the acetabulum assembly. [Embodiment Item 9] 2. The replacement hip prosthesis of embodiment 1, wherein the plurality of sensors includes a plurality of contact sensors disposed on an outer surface of the acetabulum assembly. [Embodiment 10] 2. The replacement hip prosthesis of embodiment 1, wherein the plurality of sensors includes a plurality of strain sensors disposed between the femoral head and the acetabulum assembly. [Embodiment 11] 2. The replacement hip prosthesis of embodiment 1, wherein the plurality of sensors includes an accelerometer disposed on the femoral stem. [Embodiment 12] 2. The replacement hip prosthesis of embodiment 1, wherein the acetabular assembly includes an acetabular shell and an acetabular liner. [Embodiment 13] 8. The replacement hip prosthesis of embodiment 7, further comprising a strain sensor disposed between the acetabular liner and the acetabular shell. [Embodiment 14] A medical device comprising a prosthetic femoral stem and a plurality of sensors coupled to the femoral stem. [Embodiment 15] A medical device comprising: a prosthetic femoral head; and a plurality of sensors coupled to the femoral head. [Embodiment 16] A medical device comprising: a prosthetic acetabular assembly; and a plurality of sensors coupled to the acetabular assembly. [Embodiment 17] 17. The medical device according to any one of embodiments 14 to 16, wherein the sensor is disposed in and on the surface of the medical device. [Embodiment 18] 18. The hip replacement prosthesis of any one of embodiments 14 to 17, wherein the sensor is selected from the group consisting of an accelerometer, a pressure sensor, a contact sensor, a position sensor, a chemical microsensor, a tissue metabolism sensor, a mechanical stress sensor, and a temperature sensor. [Embodiment 19] 19. The hip replacement prosthesis of embodiment 18, wherein the accelerometer detects acceleration, tilt, vibration, shock and / or rotation. [Embodiment 20] 20. The replacement hip prosthesis or medical device of any one of embodiments 1-19, further comprising an electronic processor disposed within the femoral stem and electrically coupled to the sensor. [Embodiment 21] 21. The replacement hip prosthesis or medical device of embodiment 20, wherein the electrical coupling is a wireless coupling. [Embodiment 22] 22. The replacement hip prosthesis or medical device of claim 20 or 21, further comprising a memory coupled to said electronic processor and located within said femoral stem. [Embodiment 23] 23. The replacement hip prosthesis or medical device according to any one of embodiments 1 to 22, wherein the sensors are a plurality of sensors disposed on or within the replacement hip prosthesis or medical device at a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, greater than 10 or greater than 20 sensors per square centimeter. [Embodiment 24] 23. The replacement hip prosthesis or medical device of any one of embodiments 1 to 22, wherein the sensors are a plurality of sensors disposed on or within the hip replacement at a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, greater than 10, or greater than 20 sensors per cubic centimeter. [Embodiment 25] 1. A method comprising: obtaining contact data from contact sensors positioned at a plurality of locations between the prosthetic femoral head and the prosthetic acetabulum assembly in situ in the patient's hip joint; storing the contact data in a memory disposed in a femoral stem prosthesis coupled to the femoral head; transmitting the contact data from the memory to a location external to the femoral stem. [Embodiment 26] obtaining strain data from strain sensors positioned at a plurality of locations between the prosthetic femoral head and the prosthetic acetabulum assembly in situ in the patient's hip joint; storing the strain data in a memory disposed in a femoral stem prosthesis coupled to the femoral head; 26. The method of embodiment 25, further comprising the step of: transmitting said strain data from said memory within said femoral stem to a memory located at a location external to said femoral stem. [Embodiment 27] obtaining contact data from a contact sensor positioned between the acetabular assembly and a pelvic bone of the patient while the acetabular assembly is in situ within the patient; storing the contact data in a memory located within the femoral stem; 26. The method of embodiment 25, further comprising the step of: transmitting said contact data from said memory within said femoral stem to a memory located at a location external to said femoral stem. [Embodiment 28] obtaining acceleration data from accelerometers positioned at multiple locations on a replacement hip joint assembly placed in situ within the patient's hip; storing the acceleration data in a memory provided in a femoral stem prosthesis coupled to the femoral head; and transmitting the acceleration data from the memory within the femoral stem to a memory located at a location external to the femoral stem. [Embodiment 29] a) obtaining data from a sensor of a replacement hip prosthesis or medical device according to any one of embodiments 1 to 24; b) storing the data in a memory located at a storage site within the replacement hip prosthesis or medical device according to any one of embodiments 1 to 24; and c) transmitting said data from said memory to a location external to said storage site. [Embodiment 30] 30. The method of embodiment 29, wherein the replacement hip prosthesis or medical device is implanted within a patient and the data is transmitted to a site external to the patient. [Embodiment 31] 31. The method of embodiment 30, wherein the data is transmitted to a watch, a wristband, a mobile phone, or eyeglasses. [Embodiment 32] 31. The method of embodiment 30, wherein the data is transmitted to a residence or office. [Embodiment 33] 31. The method of embodiment 30, wherein said data is transmitted to a health care provider. [Embodiment 34] The method of any one of embodiments 25 to 33, further comprising the step of analyzing said data. [Embodiment 35] 1. A non-transitory computer-readable storage medium having stored contents for configuring a computing system to perform a method, the method comprising: identifying a patient, the identified patient having at least one wireless hip implant, the hip implant having one or more sensors; detecting a wireless interrogation unit to collect sensor data from at least one of said respective sensors; and receiving the collected sensor data. [Embodiment 36] A storage medium as described in embodiment 35, wherein the stored content configures a computer system to perform the method, the method further comprising the steps of removing sensitive patient data from the collected sensor data and analyzing the data according to the type or location of the sensor. [Embodiment 37] A storage medium according to any one of the embodiments 35 and 36, wherein the hip joint implant is a replacement artificial hip joint or medical device according to any one of the embodiments 1 to 24. [Embodiment 38] The storage medium according to any one of embodiments 35 to 37, wherein the data is received on a wristwatch, a wristband, a mobile phone, or glasses. [Embodiment 39] The storage medium according to any one of embodiments 35 to 38, wherein the data is received at the patient's residence or office. [Embodiment 40] The storage medium according to any one of embodiments 35 to 39, wherein the data is provided to a healthcare provider. [Embodiment 41] The storage medium according to any one of embodiments 35 to 40, wherein the data is written to one or more websites. [Embodiment 42] The method according to any one of embodiments 25 to 34 or the storage medium according to any one of embodiments 35 to 41, wherein the data is plotted to allow visualization of changes over time. [Embodiment 43] 43. The method or storage medium of claim 42, wherein the data is plotted to provide a two-dimensional or three-dimensional image. [Embodiment 44] 44. The method or storage medium of claim 42 or 43, wherein the data is plotted to provide a two-dimensional or three-dimensional animation. [Embodiment 45] 45. The method or storage medium according to any one of embodiments 42 to 44, wherein the data is used to determine the range of motion of a patient having a hip prosthesis implant or medical device. [Embodiment 46] The method or storage medium according to any one of embodiments 42 to 44, wherein the data is used to determine or predict a defect or malfunction of the artificial hip joint implant or medical device. [Embodiment 47] 1. A method for detecting deterioration of a replacement hip prosthesis or medical device, comprising: a) providing a patient with an artificial hip joint implant or medical device according to any one of embodiments 1 to 24; b) detecting changes in the sensor and thereby determining deterioration of said hip implant or medical device. [Embodiment 48] The method of embodiment 47, wherein the sensor is capable of detecting one or more physiological and / or location parameters. [Embodiment 49] 1. A method for detecting infection in a replacement hip prosthesis or medical device, comprising: a) providing a patient with an artificial hip joint implant or medical device according to any one of embodiments 1 to 24; b) detecting a change in the sensor and thereby identifying an infection in said hip implant or medical device. [Embodiment 50] The method of embodiment 49, wherein the change in the sensor is an increase in temperature. [Embodiment 51] 26. A method of imaging a hip replacement or medical device, comprising detecting changes in sensors disposed in, on, and / or within the hip replacement or medical device of any one of embodiments 1-24, wherein the hip replacement or medical device has a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, greater than 10, or greater than 20 sensors per square centimeter. [Embodiment 52] 26. A method of imaging a hip implant or medical device, comprising detecting changes over time in sensors disposed in, on, and / or within the hip implant or medical device of any one of embodiments 1 to 24, wherein the hip implant or medical device has a density of greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 6, greater than 7, greater than 8, greater than 9, greater than 10, or greater than 20 sensors per cubic centimeter. [Embodiment 53] The method of embodiment 51 or 52, wherein the sensor is one or more of a fluid pressure sensor, a contact sensor, a position sensor, an accelerometer, a pressure sensor, a blood volume sensor, a blood flow sensor, a blood chemistry sensor, a blood metabolism sensor, a mechanical stress sensor, and a temperature sensor. [Embodiment 54] A method for placing an artificial hip joint implant or medical device in a patient's body, comprising the steps of: a) implanting an artificial hip joint implant or medical device according to any one of embodiments 1 to 24; and b) detecting the placement of the artificial hip joint implant or medical device by detecting a sensor. [Embodiment 55] The method of embodiment 54, wherein the artificial hip implant or medical device has two or more sections, and detection of the two or more sections can be determined by analysis of one or more sensors. [Embodiment 56] 56. The method of embodiment 54 or 55, wherein the placement of the artificial hip implant or medical device can be visualized by a two-dimensional or three-dimensional display or image of the one or more sensors provided on the artificial hip implant or medical device. [Embodiment 57] 57. The method of any one of embodiments 54 to 56, wherein the step of detecting the placement of the artificial hip implant or medical device allows for determining whether the artificial hip implant or medical device has been placed incorrectly.

[0110] Any of the various embodiments described above may be combined to provide additional embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, PCT application publications, foreign patents, foreign patent applications, and non-patent literature referenced herein are incorporated by reference in their entireties. Aspects of the embodiments may be modified, if necessary, to employ concepts from various patents, patent applications, and patent application publications to provide further embodiments. These and other modifications can be made to the embodiments in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the claimed invention to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments, along with the full scope of equivalents to which the claims are entitled. Therefore, the claimed invention is not limited by the disclosure.

Claims

1. 1. A monitoring system comprising a replacement hip joint, an artificial femoral stem; an artificial femoral head coupled to the artificial femoral stem; an artificial acetabulum assembly coupled to the artificial femoral head; a plurality of sensors coupled to the prosthetic femoral stem, the plurality of sensors including an acceleration sensor for measuring acceleration and a rotation sensor for measuring rotation, the plurality of sensors configured to obtain data that, when implanted in a subject, can measure a full range of motion of the replacement hip prosthesis, including degrees of flexion, extension, abduction, adduction, external rotation, internal rotation, and rotation in flexion; the monitoring system further comprising a memory for storing data collected by the plurality of sensors and an antenna for transmitting data to a location outside the replacement hip joint prosthesis, each of the memory and the antenna being coupled to the prosthetic femoral stem; The monitoring system further comprises an electronic processor disposed within the femoral stem prosthesis and electrically coupled to the plurality of sensors, the memory being coupled to the electronic processor and disposed within the femoral stem prosthesis; the monitoring system further comprises an interrogation module operating under the control of a control unit, the control unit including a microprocessor for a controller, I / O circuitry for interfacing with the interrogation module, and a power supply; A monitoring system comprising a replacement prosthetic hip joint, wherein the plurality of sensors further comprises an articular surface wear sensor for monitoring erosion of the articular surface, the articular surface wear sensor being a contact pressure sensor embedded within the prosthetic acetabulum assembly and / or the prosthetic femoral head.

2. A monitoring system as described in claim 1, wherein the plurality of sensors further includes a contact sensor positioned between the artificial femoral head and the artificial acetabulum assembly.

3. A monitoring system as described in claim 1, wherein the plurality of sensors further includes a plurality of contact sensors arranged on the outer surface of the artificial acetabulum assembly.

4. The monitoring system of claim 1 , wherein the plurality of sensors includes a plurality of strain sensors disposed between the prosthetic femoral head and the prosthetic acetabular assembly.

5. The monitoring system of claim 1 , wherein electrically coupled to the sensor comprises wirelessly coupled to the sensor.

6. 10. The monitoring system of claim 1, wherein one or more processor circuits, a CPU, a memory chip, other electrical circuits, and an antenna for transmitting and receiving data are disposed within the prosthetic femoral stem.

7. 2. The monitoring system of claim 1, wherein a processor circuit, a CPU, a memory chip, and an antenna for transmitting and receiving data are disposed within the prosthetic femoral stem.

8. The monitoring system of claim 1 , wherein the plurality of sensors are disposed within the femoral stem prosthesis at a sensor density of greater than three sensors per cubic centimeter.

9. The monitoring system of claim 1 , wherein the plurality of sensors are disposed within the femoral stem prosthesis at a sensor density of greater than 5 sensors per cubic centimeter.

10. A medical device comprising a monitoring system according to any one of claims 1 to 9.

11. A method for monitoring the replacement hip prosthesis using the monitoring system according to any one of claims 1 to 9, comprising: a) obtaining said data from said plurality of sensors of said monitoring system; b) storing said data in said memory at a storage site located within the femoral stem prosthesis; c) transmitting said data from said memory to a location external to said storage site.

12. 12. The method of claim 11, wherein the replacement hip joint is implanted within a patient and the data is transmitted to a site external to the patient.

13. The method of claim 11 , wherein the data is transmitted to a watch, a wristband, a mobile phone, or eyeglasses.

14. The method of claim 11 , wherein the data is transmitted to a residence or an office.

15. The method of claim 11 , wherein the data is transmitted to a healthcare provider.

16. The method of claim 11, further comprising a step of a computer analyzing the data.

17. A non-transitory computer readable storage medium, the stored contents of which configure a computing system to perform the monitoring method of any one of claims 11 to 16, comprising: The method of monitoring includes identifying a patient, the identified patient having the replacement hip prosthesis of claim 1; detecting a wireless interrogation unit to collect sensor data from at least one of the plurality of sensors; and receiving the collected sensor data.

18. The non-transitory computer-readable storage medium of claim 17, configuring a computing system to perform the method of monitoring its stored contents; 20. The storage medium of claim 17, wherein the monitoring method further comprises filtering sensitive patient data from the collected sensor data and analyzing the data according to sensor type or location.

19. 1. A method of imaging a hip prosthetic implant, comprising:

10. A method comprising detecting changes over time in sensors disposed within the replacement hip prosthesis of claim 1, wherein the monitoring system has sensors at a sensor density greater than two per cubic centimeter.

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