Patellofemoral arthritis in a fused knee with proximal femoral focal deficiency.

A patient with proximal femoral focal deficiency (PFFD) who underwent knee fusion without patella resection and Boyd amputation at age 2.5 years developed severe symptomatic patellofemoral arthritis 10 years later that required excision of her patella. A survey among the 780 members of the Pediatric Orthopaedic Society of North America with a 58% response rate showed that 8 of the 355 pediatric orthopaedists who perform knee fusion without patellar removal in PFFD have experienced problems with patellofemoral degeneration, whereas 57 surgeons excise the patella either routinely or occasionally. Nine respondents reported they use the patella as graft to enhance knee arthrodesis. Twenty-eight surgeons reported no experience in management of patients with PFFD, 3 prefer leg-lengthening procedures as the treatment of choice, and 16 encountered problems related to prosthetic fitting. Patellar resection may be considered when knee fusion and foot amputation are performed in children with PFFD to anticipate for late patellofemoral arthritis.