RESULTS OF REVISION HIP ARTHROPLASTY USING S-ROM PROSTHESIS. FOLLOW UP AT 3 TO 8 YEARS

Abstract

Introduction: Revision total hip replacement has high rates of failure which appears to be due, in part, to deficient bone stock that does not provide an adequate environment for fixation of the implant. Cementless modular implant offers the possibility of restoration of bone stock in conjunction with adequate fixation, thus re-establishing the function of the hip without the use of additional cement. This study reviews patients treated with the S-ROM system, assessing clinical outcomes, implant stability and osseous response to the hip revisions.

Methods: Sixty two cementless revision hip arthroplasties were performed using the S-ROM prosthesis between 1996 and 2001. Fifty four were available for follow up evaluation at 3 to 8 years (median 4.5 years). Radiological analysis, patient satisfaction and Harris hip scores were assessed pre and post operatively then at average of 4.5 years later.

Results: Eighty-five percent of patients were satisfied with the result of surgery. Clinical scores improved from a preoperative value 34 to 80 points post-operatively and were maintained on further assessment at average of 4.5 years. Forty-three stems had solid bony ingrowth, nine had mild subsidence initially averaged 6.4 mm then stabilized. Two had marked initial subsidence, which also later stabilised. There was gradual filling of the osteolytic defects in 32 of the 37 (86.5%) femoral lesions.

Discussion: With improvement of the postoperative hip score by more than 50 points and absence of definite implant instability at the final follow up, the results of use of S-ROM prosthesis in the revision cases of this study seems to be successful. The follow up is relatively short, but the experience derived from this work confirms the versatility of the S-ROM prosthesis in the complex hip revision situations as well as its favourable mechanical and biologic impact on the adjacent osseous structures.