Devices, systems and methods for monitoring hip replacements

Abstract

Hip replacement prosthesis are provided, comprising a femoral stem, a femoral head coupled to the femoral stem, and an acetabular assembly coupled to the femoral head, and a plurality of sensors coupled to at least of the femoral stem, femoral head, and acetabular assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61 / 789,170 filed Mar. 15, 2013, which application is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Field of the Invention[0003]The present invention relates generally to hip replacements, and more specifically, to devices and methods for monitoring the performance of total and partial hip replacements.[0004]2. Description of the Related Art[0005]Hip replacement is one of the most common orthopedic surgical procedures. It may be carried out when the patient loses sufficient use of the hip, typically due to injury, avascular necrosis of the hip, or for the treatment of extreme and / or constant joint pain (e.g., due to various types of arthritis (such as rheumatoid or osteoarthritis)).[0006]Hip replacement can take a variety of different forms. In total hip replacement (THR), both the femoral head and the acetabulum are ...

AI Technical Summary

Benefits of technology

This patent describes a system for measuring the range of motion (ROM) of a hip joint using sensors that are integrated into a prosthetic hip joint or attached to the surrounding tissues. The sensors provide data on the ROM during physical examination and daily activities, which can be used to assess the functionality of the hip joint. The system includes an interrogation module that sends signals to the sensors, powers them up, and collects the data they collect. The interrogation module is controlled by a control unit that processes the data and communicates it for further analysis. The technical effects of this system are improved accuracy and precision in measuring ROM, as well as better understanding the movement patterns and limitations of the hip joint.

Problems solved by technology

Unfortunately, when a total hip is inserted, various complications may arise over time.

For example, as shown in FIG. 3, there may be wear between the femoral head and the acetabular liner, which leads to improper operation of the artificial hip joint.

In addition, the patient may experience inflammation and pain if there is slight movement or dislocation of any of the components.

Depending on the types of materials used for the acetabular liner (if present, as in THR) and the femoral head (both THR and Hemi-arthroplasty), there may be wear in the acetabular liner and / or the femoral head which results in loosening or partial (or full) dislocation of the joint, may degrade the performance of the hip, result in difficulty in movement and ambulation, and may cause pain and inflammation for the patient.

Erosion of the bone around the implant may be caused by material debris (metal, ceramic, and / or polyurethane fragments) generated by friction between the femoral head and acetabular cup entering the tissues surrounding the implant and causing inflammation and bone loss.

Other potential causes of inflammation and osteolysis are implant vibration and motion, mechanical wear and tear, lack of biocompatibility between the implant materials and the surrounding bone, metal allergy, and lack of biocompatibility between the bone cement and the surrounding bone.

Unfortunately, most of the patient's recuperative period occurs between hospital or office visits.

It can, therefore, be very difficult to accurately measure and follow full joint range of motion (ROM can change depending on pain control, degree of anti-inflammatory medication, time of day, recent activities, and / or how the patient is feeling at the time of the examination), “real life” prosthesis performance, patient activity levels, exercise tolerance, and the effectiveness of rehabilitation efforts (physiotherapy, medications, etc.) from the day of surgery through to full recovery.

For much of this information, the physician is dependent upon patient self-reporting or third party observation to obtain insight into post-operative treatment effectiveness and recovery and rehabilitation progress; in many cases this is further complicated by a patient who is uncertain what to look for, has no knowledge of what “normal / expected” post-operative recovery should be, is non-compliant, or is unable to effectively communicate their symptoms.

Sudden increases in strain may indicate that too much stress is being placed on the replacement prosthesis, which may increase damage to the body.

For example, a gradual, long-term decrease in strain may cause bone reabsorption around the implant, leading to loosening of the prosthesis or fractures in the bone surrounding the prosthesis.

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