Novel Force Measurement System for Soft Tissue Balance in Total Knee Arthroplasty Based on Flexible Pressure Sensor Arrays

Total knee arthroplasty (TKA) is a common treatment for terminal knee arthropathy. Soft tissue balance is one of the key factors affecting the success rate of TKA. However, current measurement systems still face great challenges in terms of accuracy and timeliness. Herein, a novel force measurement system based on a smart spacer is proposed to measure soft tissue balance in a timely and accurate manner. The smart spacer is designed according to the simulated results, where six flexible pressure sensors with a high sensitivity of 99.56 N-1 and a wide detection range of 50 N are attached to the spacer base to directly detect the soft tissue balance force. Moreover, a soft tissue balance measurement system is constructed, which can measure the force at different positions, such as the extension position (0 degrees), the middle position (45 degrees), and the flexion position (90 degrees), and display them on the computer in a timely manner. This novel real-time knee soft tissue balance measurement system provides a way for surgeons or knee joint replacement surgery robots to accurately evaluate soft tissue balance and paves the way for improving the success rate of TKA and the patient's postoperative rehabilitation.