Prognostic factors in the outcome of supracondylar femoral osteotomy for lateral compartment osteoarthritis of the knee.

OBJECTIVE: To identify the demographic and operative factors that determine outcome in supracondylar femoral osteotomy for lateral compartment osteoarthritis of the knee.

DESIGN: Clinical and radiologic review of a nonrandomized, consecutive one-surgeon series.

SETTING: A university-affiliated, elective surgical referral centre.

PATIENTS: Forty-nine consecutive patients with unicompartmental osteoarthritis of the knee, involving the lateral compartment, and of sufficient severity that the alternative surgical procedure would be total knee replacement.

INTERVENTION: Supracondylar varus osteotomy stabilized with a blade plate.

MAIN OUTCOME MEASURES: Knee function measured by the Knee Society Score and time to conversion to total knee replacement.

RESULTS: A Knee Society Score greater than 80 was obtained in 81% of patients, but in the function portion of the measurement only 30% had a similar score. After discarding the patients who died, life-table analysis demonstrated the predicted survival before conversion to total knee replacement to be 87% at 7 years. There was no correlation with patient age or sex, femorotibial angulation, amount of correction or time after the intervention. Removal of the fixation device improved the clinical result.

CONCLUSION: The role of supracondylar femoral osteotomy remains poorly defined, but the procedure can delay total knee replacement for considerable time in appropriate patients.