Clinical and Radiographic Results for the Richards Modular Hip System Prosthesis in Total Hip Arthroplasty : Average 10-Year Follow-Up

The clinical results of total hip arthroplasty using the Richards Modular Hip System prosthesis were evaluated in 41 patients (44 joints). The mean Harris hip score improved from 42 points before surgery to 82 after 1 year, 85 at 5 years, and 79 at the final examination. The average polyethylene wear rate was 0.09 ± 0.07 mm/y. Forty joints (90.9%) achieved press fit in either of the proximal or the distal stem portion, and only 4 joints (9.1%) failed to achieve press fit in both the proximal and distal stem portions. Although the 10-year survival of the stem was 94.5% and no revisions of the stem were performed, osteolysis was found at high frequency at a distal stem. The high incidence of osteolysis has been the limiting factor in the long-term success of Richards Modular Hip System. Achievement of good canal fill in both the proximal and distal stem portions did not contribute to the good long-term result of the stem.