Erythrocyte sedimentation rate and heterotopic bone formation after cemented total hip arthroplasty

The erythrocyte sedimentation rate (ESR) was analyzed in 176 patients treated with cemented total hip arthroplasty (THA) for primary osteoarthritis and correlated with the degree of heterotopic bone formation (HBF) one year after the THA. Ninety patients were treated with indomethacin in the first six postoperative weeks, and 86 patients had no antiinflammatory treatment during that same period. The ESR was measured with the Westergren method and estimated preoperatively and six and 12 weeks after THA. Patients treated with indomethacin had no or only Grade I HBF and no significant elevation in the six- and 12-week ESR. In the placebo group, 44 patients (51%) developed Grade II or Grade III HBF, and six weeks after THA, patients with Grade III HBF had a significant elevated ESR when compared with patients without or with Grade I HBF. Moreover, in patients not treated with indomethacin in the first six postoperative weeks, an ESR above 35 mm/hour 12 weeks after THA was found to be a reliable predictor for the development of severe HBF.