The purpose of this study was to evaluate the effectiveness of intermittent femoral and sciatic nerve blocks combined with an in-house physiotherapy protocol for treating postoperative knee stiffness. Sixty-eight patients with postoperative knee stiffness were evaluated for passive knee flexion and extension at different time points, beginning preoperatively and continuing throughout a median 10-month follow-up after mobilization intervention. Sciatic and femoral nerve catheters were activated 1 hour prior to each physiotherapy session, which was performed twice per day and supported by a continuous passive range of motion machine. Median time from admission to catheter removal was 4 days (range, 1-8 days). Mean hospital length of stay was 7 days (range, 2-19 days). Overall mean flexion increased significantly from pretreatment (74°) to discharge (109°; P<.01). There was no significant difference in mean flexion at 6-week follow-up compared with that at discharge (108°; P=.764), but there was a significant increase in flexion at final follow-up (120°; P=.002). Overall mean knee extension lag decreased significantly from pretreatment (5°) to discharge (0.4°; P=.001). There was no significant increase in mean extension lag from discharge to final follow-up (1°; P=.2). Overall, 11 patients underwent revision surgery for persistent stiffness. This novel protocol for continuous knee mobilization under perineural blocks is a valuable alternative to knee manipulation under anesthesia for this select group of procedures. The 2 techniques produced a similar early range of motion gain, but the reported protocol resulted in less range of motion loss at follow-up and fewer possible complications.