Functional results after surgical treatment for congenital knee dislocation.

BACKGROUND: Congenital knee dislocation (CDK) is a rare congenital deformity, which often requires surgery for treatment. Little objective data exist characterizing the outcome of patients who require operative treatment for this condition. The purposes of this study were to objectively evaluate the functional, clinical, and gait outcomes of patients who underwent surgical treatment of CDK; and compare the results of outcome between 2 surgical approaches for this condition: quadricepsplasty and femoral shortening.

METHODS: We performed a retrospective review of all patients (7) treated surgically for CDK. Patients were evaluated at an average follow-up of 12+6 years. Each patient underwent a clinical examination, functional evaluation using the Lysholm Knee Questionnaire and Pediatric Outcomes Data Collection Instrument, and a 3-dimensional gait evaluation. The results of the total group were compared with normal controls. Additionally, results of the patients treated with quadricepsplasty were compared with patients treated with femoral shortening.

RESULTS: Total knee range of motion for the entire group averaged 112 degrees, with 8 of the 9 knees having flexion>90 degrees. Seven of the 9 knees were found to have some degree of instability on examination, yet none of the patients reported using any form of brace for ambulation. Functional evaluation showed good knee specific and overall function, comparable to normal controls. There were no differences in clinical or functional outcomes between the 2 surgical approaches. Gait analysis revealed a stiff-knee gait pattern to the congenital knee dislocation group, as compared with normal controls, and subtle differences in knee function between the surgical approaches.

CONCLUSIONS: The function of patients after surgical treatment for CDK seems to be quite good compared with normal controls. Good knee specific and overall function scores are reported with limitations seen only in higher demand activities. Despite instability of the knee noticed on clinical examination, patients ambulate without braces and have a functional knee range of motion. Little difference in outcome was seen between the 2 surgical approaches used to treat this condition.

LEVEL OF EVIDENCE: Therapeutic Study, Level III.