Heterotopic Ossification After Total Knee Arthroplasty

ABSTRACT

PURPOSE: To investigate the incidence, clinical and radiological courses of the heterotopic ossification following total knee arthroplasty (TKA). MATERIALS AND METHODS: We investigated the incidence, time of detection, location, symptom and treatment of the heterotopic ossification with retrospective study in 160 cases (111 patients) of primary TKA from Mar. 1997 to Sept. 2001. RESULTS: The incidence of the heterotopoic ossification was 3.8% (5 patients, 6 cases), the mean follow-up period was 20 months (12 months to 42 months). All of preoperative disagnosis was osteoarthritis. The average time of detection was 3.5weeks (2 weeks to 6 weeks) after operation. The sites of the heterotopic ossification were anterior cortex of distal femur in 5 cases, posterior cortex of distal femur in 3 cases, quadriceps expansion in 4 cases, the femoral attachment site of the MCL in 1 case and posterior compartment of knee in 1 case. The symptom was variable painful limitaion of motion. No specific treatment had been done except continuous passive or active motion exercise. The average preoperative range of motion was 20 degree to 110 degree and at last follow-up, the average range of motion was 5 degree to 105 degree with relief of pain. CONCLUSION: Although the heterotopic ossification following TKA is a rare complication, it should be suspected in patients with painful deterioration of motion between the second and sixth postoperative week. The relief of pain and the improvement of range of motion could be achieved with the lapse of time without specific treatment except continuous passive or active motion exercise.