PERONEAL NERVE PALSY AFTER TOTAL KNEE ARTHROPLASTY - ASSESSMENT OF PREDISPOSING AND PROGNOSTIC FACTORS

Thirty-two postoperative peroneal-nerve palsies in thirty patients wer e documented in a retrospective review of 10,361. consecutive total kn ee arthroplasties performed at one institution from 1979 through 1992, The mean age of the thirty patients was sixty-five Sears (range, twen ty-eight to seventy-eight years), Four of these patients had had a pre vious proximal tibial osteotomy and five had had a previous lumbar lam inectomy. Ten knees (ten patients) had preoperative valgus alignment o f 12 degrees or more, A control group of 100 patients who had had tota l knee arthroplasty during the same period was computer-matched to the patients by age, sex, and operating surgeon, Comparison of this contr ol group with the thirty patients showed that epidural anesthesia for postoperative control of pain (p < 0.03), previous laminectomy (p < 0. 04), and preoperative valgus deformity (p < 0.0001) were significantly associated with peroneal nerve palsy The relative risk for patients w ho had had a previous proximal tibial osteotomy was doubled, but this was not significant (p < 0.4), To determine risk factors associated wi th anesthesia better, a subgroup of 4388 total knee arthroplasties per formed during a five-year period (1988 through 1992) was also studied, In this sample, twenty-five peroneal-nerve palsies were documented, E ighteen occurred after epidural anesthesia (p < 0.03); five, after gen eral anesthesia; and two, after spinal anesthesia. An important findin g of this study is the high frequency of delayed presentation of peron eal nerve palsy We believe that epidural anesthesia for postoperative control of pain leads to decreased proprioception and sensation postop eratively, It is postulated that positioning of the limb in this unpro tected state may be a factor in the late development of palsy The conc ept of the so-called double-crush phenomenon may partially explain the palsy seen in the patients who had had a lumbar laminectomy and asymp tomatic peripheral neuropathy.