Congenital Synostosis of the Knee: Long-term Outcomes of Limb Reconstruction Surgery.

Abstract

Congenital synostosis of the knee is a rare condition with limited data on treatment options and outcomes. This study reports clinical findings, treatment approach, and surgical/clinical outcomes for congenital synostosis of the knee. An institutional review board-approved retrospective review of patients with congenital synostosis of the knee presenting to 2 institutions between 1997 and 2021 was performed. Eight patients (13 knees) with a median follow-up of 11.3 years (3.3 to 17y) were included. Seven patients had associated syndromes. Patients presented with an average knee flexion deformity of 100° (range 60 to 130°) and delayed walking ability. Seven patients had associated upper extremity hypoplasia/phocomelia. The average age at the index surgery was 4.3 years (range 1.2 to 9.2y). Synostosis resection with gradual deformity correction was performed in most patients. An attempt was made at a mobile knee in some patients, but all went on to knee fusion. Mean flexion deformity at final follow-up was 11.6° (range: 0 to 40°) and 5 limbs were fused in full extension. Mean limb length discrepancy at final follow-up was 6.8cm (range: 0 to 8cm). All patients maintained their improved ambulation status at final follow-up. Twenty-two complications were identified. Reliable correction of the deformity associated with congenital knee synostosis was achieved at a median follow-up of 11 years. Importantly, all patients maintained their improved ambulation at final follow-up. This is the largest study on patients with congenital knee synostosis and outlines a reconstructive approach to improve ambulatory status. Level IV.