Patellar Instability in Juvenile Amputees

JOHN McIVOR, MD, FRCSC**, AND ROBERT GILLESPIE, FRCSC, FRCS (EDINEdmonton, Alberta


Forty-three knees in a sample of 14 girls and 27 boys were reviewed by history, physical examination, and radiographs. Seventeen had Syme's and 26 had below-knee amputations performed for trauma in 13 patients and for revision of congenital anomalies in 28 patients. Eleven had patellar instability and three had pain in the patello-femoral joint. Radiographs revealed patella alta, lateral subluxation, and patellar hypoplasia in all cases. Of 31 asymptomatic patients, 68 percent had patella alta, and 35 percent had hypoplastic patellae. Patients with problematic patellar instability were managed successfully with prosthetic modifications in four cases and surgery in two cases. One surgical procedure failed. The group with patella alta had more below-knee amputations and had worn a prosthesis longer than the group with normal knees.

Pressure of the prosthesis in the region of the patellar tendon in a growing child may lead to patella alta which may contribute to patellar instability.

**214 11520 100th Avenue, Edmonton, Alberta, Canada T5K OJ7