Towards better understanding the need for better joint force monitoring when balancing knee joint force during Total Knee Replacements.

Abstract

Osteoarthritis (OA) is the most common joint disease affecting 18% of women and 10% of men over 60 (1). OA breaks down the articular cartilage in the joint in excess either from, old age, trauma, mechanical wear, or obesity which results in abnormal regrowth of the bone, causing swelling, pain, and reduced mobility of the joint (2,3). A partial or a total knee replacement of joint, in this case knee (TKR) is often implemented by removing the affected area and replacing it with a metal and polymer prothesis (4). However, TKRs in practice often result in failure, requiring revision surgery (5). One important element in any joint operation is the adjustment of the initial tension and forces holding the joint in position while still providing sufficient initial tension to prevent dislocation or excess stress in a normal unloaded condition. Excess initial load can result is higher stress causing a bone fracture or joint failure due to debonding or looseness. Correct initial tension setting and alignment ensures correct kinematics and an adequate range of motion. Research speculates the importance or lack thereof of proper tension and alignment in the knee joint and discusses various force measurement techniques, some being artisan in nature. The introduction of new technology such as robotic manipulator arms or dedicated contact force sensors can measure contact forces intraoperatively when limb is in a passive state and link it to the forces involved in walking and running. These forces are important as it controls the range of motion as well as the gait symmetry. This paper investigates the nature of force monitoring using a force plate during gait analysis and comparing it with data from smart transducers used intraoperatively for knee force measurements to discuss how these two can inform each other.