Long-term results with the cemetless CLS stem in hip replacement

Objective: The present work aims at evaluating the clinical and radiological long-term results of the cementless CLS stem in hip replacement. Method: Sixty-six consecutively operated patients were examined clinically and radiologically at an average follow-up time of 10.7 (7.6 - 13.8) years. The clinical evaluation was done with the Merle d'Aubigne and the Harris hip scores. The radiological evaluation included the evaluation of radiolucencies as well as the occurrence of heterotopic ossifications. Results: A total of four stems had to be revised (two infections, two periprosthetic fractures). No stem revision had to be done because of aseptic loosening. This results in a survival rate of 94.5% according to Kaplan-Meier. The mean Merle d'Aubigne scores increased from 9.0 preoperatively to 16.0 points at follow-up. The mean follow-up Harris hip score was 87.3 points. Periprothetic osteolytic zones were observed in 45% of the cases, particularly in the Gruen zones 1 and 7. These osteolytic zones were mainly found in connection with cementless polyethylene cups. Conclusion: The results of this study confirm the positive short and medium-term results with the CLS stem in a long-term process. The formerly described phenomenon of the residual thigh pain with cementless stems was clearly minimized.