LONG-TERM FOLLOW-UP OF THE UNCEMENTED CLS STEM IN VERY YOUNG PATIENTS (< 45 YEARS)

Abstract

Introduction: Despite improved cementing techniques, the long term survival of hip arthroplasty in younger patients have been disappointing. THA in this group of young and active patients remains a major challenge. Consequently, cementless components have been developed. Longer implant survival, preservation of bone stock and ‘easier’ revisions have been advocated as potential benefits of cementless stems. Up to date there are only few reports in the literature on the long term results of uncemented stems. Like in cemented THA, 10 year survival of at least 90% is required for any THA.

Materials and Methods: We followed 133 implantations of an uncemented, grit blasted straight titanium stem (CLS, Zimmer Inc, Warsaw, USA). The mean follow-up evaluation was 14 (10 – 20) years. The mean age at surgery was 37 (16 – 45) years.

Results: At follow-up, 14 patients (10,5%) had died, and 10 (7,5%) were lost to follow-up. 3 patients under-went femoral revision. One for infection an two for aseptic loosening of the stem. There was no case of clinical or radiographic loosening at the time of follow-up. Overall survival was 96% at 14 years, survival with femoral revision for aseptic loosening as an end point was 97% at 14 years. The mean Harris-Hip-Score at follow-up was 81 points (range 45–100). 96 hips were available for radiolographic evaluation. Radiolucent lines (< 2mm) in Gruen zone 1 were present in 7 hips and in Gruen zone 7 in 2 hips, respectively. Small osteolytic lesions (< 1cm) in Gruen zone 1 were present in one hip and in Gruen zone 7 in 5 hips. Larger lesions (> 1cm) were present in one case in Gruen zone 1 and 7. No osteolysis or radiolucency was found in zones 2 – 6. No case of severe femoral osteolysis was found.

Conclusions: The long-term results with this type uncemented stem in a young and active patient group are encouraging and better than those of cemented stems in this age group. We recommend the uncemented CLS stem for hip arthroplasty in young demanding patients.