Stable bony integration with and without short-term indomethacin prophylaxis - A 5-year follow-up

We included in a prospective study of a standardized indomethacin protocol 134 consecutive patients undergoing primary cementless endoprosthetic hip r eplacement between January and June 1990. Periarticular heterotopic ossific ation (HO) was graded according to the Arcq classification (grades 0 to III ). At final follow-up, all patients were analyzed clinically and radiograph ically for HO and aseptic loosening. A similar group of 44 patients (mean a ge of 64 years, range 38-82 years) undergoing total hip replacement (THR) w ith the same prosthesis and technique in 1987 did not receive HO prophylaxi s and served as a control group. The average age of the 134 prophylaxis pat ients was 66.5 years (range 32-85 years), and the average follow-up was 65 months (range 60-71 months). Thirty patients (25%) were lost to final follo wup (19 died, 10 unknown, 1 amputation). In the study group, 77% had HO gra de 0, while none had I-IO grade III, compared with 18% HO grade 0 and 16% H O grade III in the control goup. These differences were statistically signi ficant (P = < 0.001). At a minimum of 60 months follow-up, clinical and rad iographic evaluation revealed no aseptic loosening in the study group: 4 ca ses of prosthesis subsidence during the first year did not progress. In the control group, there was a higher incidence of radiolucency around the fem oral component, and one patient met all criteria for radiographic evidence of aseptic loosening. Statistical analysis revealed no significant differen ce between the two groups (P = 0.104). Based on our clinical and radiologic al results, indomethacin does not inhibit stable bony integration of the fe moral component.