Seventeen-year survival of the cementless CLS Spotorno stem

For primary uncemented hip arthroplasty, various stem designs are available. The cementless CLS((R)) Spotorno stem has been used for more than 20 years. We re-evaluated a group of patients previously examined for a 10-year follow-up to assess the clinical and radiological stem performance in the long run.

Between 1987 and 1988, a consecutive series of 107 uncemented CLS((R))-Spotorno stems (Zimmer Ltd., Germany) were implanted in 94 patients. The patients' mean age at the time of surgery was 51 years (range 20-77 years); 80 hips out of 107 (86%) were available for a clinical examination [Harris Hip Score (HHS)] after a mean of 17 years (range 15-18 years). In addition, radiographs were available from 74 out of 80 examined hips (92%) and analyzed for radiolucency, stress shielding, stem migration and heterotopic ossification.

Stable stem fixation was present in 64 hips (98.5%). With "non-traumatic loosening" as an endpoint, stem survival was 100% after 17 years. Two stems (3%) showed mild subsidence already in the 10-year follow-up with no progression after 17 years. The HHS described excellent results in 47 hips (59%), good results in 16 hips (20%) and fair or poor results in 7 hips (9%) and 10 hips (13%), respectively. Radiolucency and grades II and III stress shielding were progressive at 17 years compared with the 10-year results. Grade IV stress shielding associated with osteolysis was seen in 9 hips (14%). Thigh pain was present in 20 hips (25%).

The CLS((R)) Spotorno stem allows excellent long-term results in cementless hip arthroplasty, leaving only minimal options for substantial improvements. Our findings on progressive stress shielding point towards a more diaphyseal load transfer of the CLS stem.