Nerve palsy after knee arthroplasty in patients with rheumatoid arthritis.

Forty-two consecutive knee arthroplasties on rheumatoid knees (19 Attenborough, 20 Total Condylar, 3 Marmor) were examined pre- and postoperatively for signs of below-the-knee nerve lesions. Sixteen of these knees were also studied neurophysiologically (EMG). Four patients (knees) had peroneal nerve palsy, three early and one late. Three further knees had only EMG signs of nerve lesion. Predisposing factor was correction of flexion contracture of more than 10 degrees and especially when combined with varus change in alignment. Preoperative EMG could not predict nerve lesion.