THE UNCEMENTED PRIMARY BICONTACT STEM IN REVISION TOTAL HIP ARTHROPLASTY

Abstract

Introduction: Revision in total hip arthroplasty (THA) continues to be a technical challenge because of difficulties in fixation of the femoral component in mostly deficient bone in the proximal femur. In the past, the use of primary stems in revision surgery has also been described by many authors. Very often, the cortical bone is not sufficient enough for torsional or axial load bearing. In this retrospective study we present our clinical results of femoral component revision surgery using the uncemented primary BiCONTACT stem (Aesculap).

Methods: In this study, seventy-nine patients were examined who underwent a revision of the femoral component in total hip arthroplasty (THA) with the uncemented primary BiCONTACT stem between December 1991 and April 2004 (mean follow-up 6.8+/−3.9 years). Only patient with a defect classification of Paprosky I–II were analysed. The average patient age was 67.1+/−10.1 years (range from 34–87 years). Forty-six female and thirty-three male patients (168+/−10 cm mean height, 75+/−12 kg mean weight, mean Body Mass Index: 26.4+/−2.5) were included in the study. All patients were clinically evaluated both preoperatively and postoperatively using the Harris Hip Score (HHS), a pain score (from 0 [no pain], to 10 [max. pain]) and a motion score (from 0 to [no flexion], to 10 [max. flexion]). Furthermore, the radiographs (anteroposterior and axial) before, after surgery and at follow-up were analysed concerning femoral defects, proximal bone loss, and to determine the quality of bony fixation. The defects were classified using the Paprosky classification. For statistical analysis, the paired Student t-test was used for preoperative and postoperative data.

Results: The postoperative Harris Hip Score (78.9+/−12.5, p < 0.001), Range of Motion Score (p < 0.05) and Pain Score (p =0.005) improved significantly. During follow-up there were only four re-revisions within two years after revision surgery: two re-infections in the first year, two aseptic loosening in the second year. There were only two cases of mild stress shielding. The survival curve (Kaplan-Meyer) showed a 10-years survival rate of 96.2 %. In two cases we found intraoperative periprosthetic fractures and in fourteen cases small fissures during removal or implantation of the stem.

Discussion: The primary uncemented BiCONTACT stem appears to be a good alternative to other revision systems in well-selected femoral revision cases with minor defects. The results of this study correspond to those published before, using a primary cementless stem in cases of revision. Therefore, in cases of minor proximal and metaphyseal bone defects (Paprosky I–II) the use of a primary stem in femoral revision should be considered. However, an exact preoperative planning, intraoperative assessment of bone stock, and experienced surgeon is necessary.