[130] Towards a better understanding of the need for better joint force monitoring when balancing knee joint force during total knee replacements
S Noroozi1, Z Searle1, S Al-Nasser1 and A Harvey2
1Bournemouth University, UK
2The Royal Bournemouth Hospital, UK
Osteoarthritis (OA) is the most common joint disease affecting 18% of women and 10% of men over 60. OA is where articular cartilage in the joint is removed in excess either by old age, trauma, mechanical wear or obesity which results in abnormal regrowth of the bone, causing swelling, pain and reduced mobility of the joint. If OA is in the knee, it can reduce a person’s ability to walk on level ground and walk upstairs, reducing the amount of work and daily tasks they can perform and is considered a major disability. For this reason, a partial or a total knee replacement joint, in this case knee (TKR), is often implemented by removing the affected area and replacing the damaged areas with a metal and polymer prosthesis. One important element in any joint operation is the adjustment or presetting of the initial tension or forces holding the joint in position. Currently, there are no ideal tension or load intensities existing to target for. Sufficient initial tension is to prevent dislocation. Excess tension causes overload or stress in the joint. The excess initial load can result in higher stress during ambulation that can also cause joint failure. Correct initial tension and alignment ensure correct kinematics as well as normal range of motion. Some joints have single hemispherical contact surfaces such as the shoulder or hip and some have multiple contact surfaces. Surgeons are speculating about the importance of accurate joint force measurement during joint operation and discuss various force measurement techniques such as the use of robotics manipulator arms or force plate or dedicated force transducers. These forces are important as they control the outcomes such as symmetry or range of motions. In this paper, we are investigating the nature of the forces through knee during gait analysis. Measuring force using a force plate, and interpolating it, to force through the knee is different from measuring forces in the joint during operation. The later needs dedicated smart transducers. The relative merit is discussed and how these two can inform each other.
