Relationship between Postoperative Knee Extension Lag and Preoperative Limitation of Knee Extension in Patients with Total Knee Arthroplasty

Abstract

[Purpose] The purpose of this study was to investigate the time course of knee extension lag (Lag) up to 3 months after total knee arthroplasty (TKA) to clarify its relationship with preoperative knee extension range of motion (ROM). [Subjects and Methods] The subjects were 22 patients diagnosed as having bilateral varus knee osteoarthritis who received primary TKA. Lag was measured at 1, 2, 3 and 4 weeks, and 3 months after TKA. Hierarchical multiple regression analysis was performed using Lag at 3 months post-TKA as the objective variable, and the preoperative values of the operated-side knee pain, bilateral knee flexion and extension ROM, and bilateral femoral-tibial angles as the explanatory variables. [Result] Lag of more than 5° was found in 19 (86.4%) patients at 1 week, and 9 (40.9%) patients at 3 months post-TKA. The preoperative operated-side knee extension ROM significantly contributed to Lag at 3 months post-TKA. [Conclusion] The results suggest that preoperative operated-side knee extension ROM is related to Lag at 3 months post-TKA.