To determine the prevalence of heterotopic bone formation in cemented versus noncemented total hip joint replacement.
A prospective randomized controlled trial. Follow-up ranged from 2 to 6 years (mean 4 years).
A university hospital.
Two hundred and twenty-six patients who had primary or secondary osteoarthrosis of the hip were stratified according to type of fixation, surgeon and age. Patients were randomized within strata: 112 received noncemented total hip prostheses and 114 received cemented prostheses. The 2 groups were similar with respect to age and sex.
Primary total hip arthroplasty. A cemented (methylmethacrylate) or noncemented prosthesis was inserted by a lateral surgical approach.
The Brooker classification was used to grade heterotopic bone formation from postoperative radiographs.
Overall, 148 (66%) hips had no heterotopic ossification, 56 (25%) were Brooker class I, 14 (6%) were class II, 8 (3%) were class III and none were class IV. In the noncemented group of patients, 76 (68%) hips had no heterotopic ossification, 25 (22%) were Brooker class I, 7 (6%) were class II, 4 (4%) were class III and none were class IV. In the cemented group of patients, 72 (63%) hips had no heterotopic ossification, 31 (27%) hips were Brooker class I, 7 (6%) were class II, 4 (4%) were class III and none were class IV.
There was no significant difference in the prevalence of heterotopic ossification between cemented and noncemented total hip replacements in patients with osteoarthrosis.