A Method for Widening the Range of Force Measurement and Gap Adjustment in the Total Knee Replacement

The artificial knee replacement (TKR) surgery is one of the major surgeries to cure the severe pathological changes in the knee for osteoarthritis. The soft tissue balance is very important to prolong the artificial joint´s life in the TKR, the authors have developed a soft tissue balance measurement system to meet the quantitative soft tissues balance measurement requirement in the TKR. In the system applications, we found that the system can not fully satisfy the range of the soft tissue´s force measurement and gap adjustment. In this paper, we proposed a method to widen the range of the force measurement based on the level principle, and gap adjustment by combining the adjustable mechanical structure with fixed thickness block. And by designing some different shapes of touch plate, the system can measure the soft tissue´s force generated in the different parts round the knee. The preliminary test shows that the measurement system can evidently improve the force measurement range and the gap adjustment range in the knee joint, and largely reducing the designing the difficulty of the mechanical machining.