Effects of multimodal pain management following total knee arthroplasty on gait recovery and falls

Purpose Adequate post-operative pain control is essential for recovery after total knee arthroplasty (TKA). Periarticular multimodal drug injection (PMDI) and femoral nerve block (FNB) are commonly used. Although continuous FNB provides effective analgesia, it may impair quadriceps strength and increase the risk of delayed recovery and post-operative falls. This study evaluated the effects of different analgesic strategies on functional recovery and falls after TKA. Methods This retrospective cohort study included 183 patients undergoing unilateral primary TKA. Patients were divided into three groups: PMDI alone (PMDI group, n = 54); continuous FNB combined with PMDI (cFNB group, n = 79); and single-shot FNB combined with PMDI (sFNB group, n = 50). All patients followed a standardized rehabilitation protocol from post-operative day 1. Outcomes included pain scores, opioid consumption, fall events, time to walking with a cane, hospital stay, and functional outcomes at discharge. Results Time to walking with a cane was significantly longer in the cFNB group ( p = 0.01). No differences were observed in discharge outcomes or hospital stay. The cFNB group had lower pain scores on post-operative day 1, with a higher proportion achieving Numerical Rating Scale for pain ≤ 2 ( p = 0.042). Falls were more frequent in the cFNB group (10.1%), although not statistically significant ( p = 0.094), and most occurred within 2 days. Conclusions Continuous FNB improves early analgesia but may delay gait recovery and increase early post-operative fall risk. Careful post-operative monitoring and fall prevention strategies are recommended when continuous FNB is used.