Mid-term results of the cementless CLS stem

Between 1986 and 1990, 335 primary total hip arthroplasty (THA) were performed using the cementless CLS stem. The mean age at surgery was 55.3 years. The retrospective study was performed at an average follow-up time of 8.9 years. A total of 232 patients (69.3%) underwent clinical and radiological examination, 33 patients (9.9%) were interviewed by telephone, and 9 stems (2.7%) had been replaced meanwhile. The mean Harris hip score was 91.7 points, and the mean Merle D’Aubigne score was 16.8 points. One stem had subsided during the first postoperative year. Ectopic ossifications classified as Brooker III were noted in 5.7%, with no Brooker IV being seen. Radiolucent lines were found in 43.5%, and 11% showed enlargement with time. Focal osteolyses were present in 36%, of which 24% progressed with time. At the latest follow-up, we did not find any stem loosening clinically or radiologically.