Postarthroplasty palsy, occurrence of dysfunction of the sciatic or peroneal nerve after total joint replacement of the hip or knee, is a complication that remains poorly understood Characteristics of a series of 24 patients with postarthroplasty palsy are reviewed, with the finding that, overall, 58 4% of the patients had an underlying peripheral neuropathy. The role of this neuropathy predisposing the arthroplasty patient to stretch/traction injury is discussed and should be emphasized as a risk factor prior to surgery and should influence the surgeon's intraoperative use of force during the arthroplasty procedure. This clinical problem is addressed from the perspective of peripheral nerve surgery, with an algorithm suggested for its management The algorithm suggests that if a peroneal palsy is still present at 3 months after an arthroplasty and neurosensory testing falls to demonstrate a sensory reinnervation pattern in the territories of the deep or superficial peroneal nerve then surgical neurolysis of the common peroneal nerve is indicated.