[Prevention of heterotopic ossifications in hip arthroplasty: effectiveness of selective Cox-2 inhibitors (celecoxib) versus ketoprofen].

PURPOSE OF THE STUDY

Peri-prosthetic ossifications are a frequent complication of total hip arthroplasty, which, if effective preventive measures are not taken, occur in 60% of patients. Numerous classic antiinflammatory agents have shown their preventive efficacy. New selective Cox-2 inhibitors offer the possibility of reducing the adverse effects of antiinflammatory drugs but remain to be proven effective in this indication. The purpose of this pilot study was to compare the efficacy of celecoxib versus ketoprofen.

MATERIAL AND METHODS

In order to obtain sufficient statistical power to have a 70% chance of detecting a 25% difference between the two treatments with a 5% risk of error, we evaluated the incidence of peri-prosthetic ossifications of the hip in a prospective monocentric series of 52 patients receiving 400 mg celecoxib a day during a week. It was compared with the incidence in a control series of 52 matched patients (same age, gender, diagnosis, operator experience) given 200 mg ketoprofen iv for 48 hr then 300 mg po for 5 days as preventive treatment. Ossifications were studied on the plain AP view of the pelvis at a mean follow-up of more than 11 months (11.4 vs 11.9). The Brooker classification was determined.

RESULTS

The percent of patients presenting peri-prosthetic ossifications was equivalent. For the celecoxib group, 60% of the patients were free of ossifications; 28.9% presented stage 1 ossification and 11.1% stage 2 ossification; none of the hip exhibited a higher stage. In the ketoprofen control group, 53.2% of patients were free of ossification, 38.2% had stage 1 ossification, 6.4% stage 2, and 2.1% stage 3; there was no patient with stage 4. Fisher's exact test did not demonstrate a significant difference between the groups (p<0.51). Compared with an older series of patients who were not given preventive treatment, there was a significant reduction in incidence of peri-prosthetic ossification (p=0.014).

DISCUSSION

The two study groups were not significantly different for age, gender, or underlying disease. There were an equivalent number of cases of intolerance to treatment in the two groups.

CONCLUSION

These findings appear to indicate an equivalent efficacy for celecoxib and ketoprofen for the reduction of peri-prosthetic ossifications. Based on these results, a randomized prospective comparative study can be undertaken without risk of losing effective prevention in one group. This prospective study should enable a more precise evaluation of treatment equivalence and quantify any potential gain in morbidity obtained with celecoxib.