LONG-TERM (15 –20 YEAR) RESULTS OF THE UNCEMENTED CLS STEM IN YOUNG AND ACTIVE PATIENTS UNDER THE AGE OF 55 YEARS.

Abstract

Introduction: THA in young and active patients remains a major challenge. Uncemented femoral components have been advocated in young patients, but there are only few reports with more than 10 years follow-up.

Materials and Methods: We followed the first 153 consecutive implantations of an uncemented, straight femoral stem (CLS, Zimmer Inc, Warsaw, USA) in 141 patients. Mean time of follow-up evaluation was 17 years (range, 15 – 20 years), mean age at surgery was 47 years (23–55).

Results: At follow-up, 20 patients (20 hips) had died, and 7 (7 hips) were lost to follow-up. 10 patients (10 hips) underwent femoral revision- 1 for infection, 4 for periprosthetic fracture, and 5 for aseptic loosening of the stem. Overall survival was 91% at 17 years (95%-confidence limits, 88%–94%), survival with femoral revision for aseptic loosening as an end point was 95% (95%-confidence limits, 93% – 98%). The mean Harris-Hip-Score at follow-up evaluation was 84 points. 116 hips were available for radiolographic evaluation. Radiolucent lines (< 2mm) in Gruen zones 1 and 7 were present in 12,9% (15 hips) and 13,8% (16 hips), respectively. Radiolucencies in zones 2 – 6 were found in 0,9% (1 hip) – 2,6% (3 hips) on ap x-rays. Only one case of distal osteolysis was found after a previous Wagner resurfacing. No case of severe femoral osteolysis was found at follow-up.

Conclusions: The long-term results with this type of uncemented femoral component are encouraging and compare favorably with those achieved in primary cemented total hip arthroplasty in this group of young and active patients.