Influence of intra-operative parameters on postoperative early recovery of active knee flexion in posterior-stabilized total knee arthroplasty
Nagai, K., Muratsu, H., Matsumoto, T. et al.Knee
Purpose
Active knee flexion is more important for daily activities than passive knee flexion. The hypothesis is that the intra-operative parameters such as osteotomized bone thickness and soft tissue balance affect the postoperative active flexion angle in total knee arthroplasty (TKA). Therefore, we evaluate the influence of intra-operative parameters on postoperative early recovery of active flexion after posterior-stabilized (PS) TKA.
Methods
The subjects were 45 osteoarthritic knees undergoing primary PS TKA with anterior-reference technique. Intra-operative soft tissue balance was measured using an offset type tensor, and each osteotomized bone thickness was also measured. Pre- and postoperative active knee flexion angles were measured using lateral radiographs. Liner regression analysis was used to determine the influence of these intra-operative parameters on postoperative active flexion angles or recovery of active flexion angles.
Results
Pre-operative flexion angle was positively correlated with postoperative flexion angle (R = 0.52, P = 0.0002). Postoperative flexion angle was negatively correlated with the osteotomized bone thickness of femoral medial posterior condyle (R = −0.37, P = 0.012), and femoral lateral posterior condyle (R = −0.36, P = 0.015). Recovery of flexion angle was slightly negatively correlated with gap difference calculated by subtracting joint gap at extension from that at flexion between osteotomized surfaces (R = −0.30, P = 0.046).
Conclusions
The osteotomized bone thickness of the femoral posterior condyle is a significant independent factor of postoperative flexion angles. This indicates that the restoration of the posterior condyle offset may lead to larger postoperative active flexion angles in PS TKA.
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