Introduction: High survival rates have been reported for the uncemented CLS Spotorno stem up to 20 years. To confirm survival at longer follow-up we report the minimum 20-year (mean, 22 years; range, 20–25 years) results using this device.

Methods: We retrospectively evaluated the clinical and radiographic results of a consecutive series of 354 total hip arthroplasties using an uncemented grit-blasted, tapered femoral stem (CLS Spotorno) in 326 patients. Mean time of follow-up evaluation was 22 years (range, 20–25 years), mean age at surgery was 57 years (range, 13–81 years). Clinical results were evaluated using the Harris Hip Score. Kaplan-Meier survivorship analysis was used to determine long term outcomes for different end points.

Results: At final follow-up, 126 patients (136 hips) had died, and 7 patients (8 hips) were lost to follow-up. Forty-one hips (12%) in 38 patients underwent femoral revision – 10 (3%) for infection, 12 (3%) for late periprosthetic fracture, and 19 (5%) for aseptic loosening of the stem. Kaplan-Meier analysis, with revision of the femoral component for any reason as the end point, revealed that the survival rate at 22 years was 86% (95%-confidence limits, 82%–90%). The survival rate with femoral revision for aseptic loosening as the end point was 93% at 22 years (95%-confidence limits, 90% – 96%).

Discussion and Conclusion: The long-term results with this type of uncemented femoral component are encouraging and compare to the best reported series in primary cemented total hip arthroplasty. Besides aseptic loosening, periprosthetic femoral fracture is an important mode of failure in the long term following uncemented THA.

Introduction: Continous periprosthetic bone loss after uncemented THA may lead to proximal femoral atrophy and increase the risk for aseptic loosening or peripros-thetic femoral fracture in the long-term. Little is known about the extent and the pattern of bone remodeling around stable, straight uncemented stems after 15 years.

Patients and Methods: In a prospective longitudinal study, bone mineral density (BMD) was measured in 131 patients with 146 stable, uncemented, double- tapered, grit- blasted stems (CLS Spotorno, Zimmer, Warsaw, USA) using dual- energy x-ray absorptiometry (DEXA) after a mean of 12 years (range:10–15, t1) postoperatively. Patients were followed with radiographs and Harris hip scores (HHS), and a second and third DEXA were performed at a mean follow-up of 17 years (range: 15–20, t2) and 22 years (range: 20–25, t3) using the identical protocol.

Results: We obtained a complete prospective set of data of three consecutive DEXA measurements for 37 hips (32 patients, 14 male, 18 female). In all cases regular bone ongrowth did occur and on radiographic evaluation there were no signs of loosening and no significant change in periprosthetic bone formation. There was no case of severe bone loss and no case of diaphyseal cortical hypertrophy. We analyzed the differences in overall femoral BMD (netavg) and in BMD in zones 1–7 according Gruen. There was no significant change in overall netavg BMD for both male and female patients (p> 0,05) comparing t1 and t3. We found a significant change in periprosthetic BMD in zone 7 (−6,62%, p< 0,05) in male patients and in zones 1, 6 and 7 (−8,7%/−5,1%/−14,2%, p< 0,01/0,05/0,01) in female patients.

Discussion and Conclusion: The results of our study suggest that there are no clinically relevant changes in overall periprosthetic BMD around stable, uncemented straight stems in the long- term. However, continuous bone remodeling with slow but steady proximal bone loss occurs, predominantly in female patients. Once osseous integration is observed, stress shielding remains moderate and changes in periprosthetic BMD are limited to the metaphyseal region.

Peri-prosthetic femoral fracture after total hip replacement (THR) is associated with a poor outcome and high mortality. However, little is known about its long-term incidence after uncemented THR.

We retrospectively reviewed a consecutive series of 326 patients (354 hips) who had received a CLS Spotorno replacement with an uncemented, straight, collarless tapered titanium stem between January 1985 and December 1989. The mean follow-up was 17 years (15 to 20). The occurrence of peri-prosthetic femoral fracture during follow-up was noted. Kaplan-Meier survival analysis was used to estimate the cumulative incidence of fracture.

At the last follow-up, 86 patients (89 hips) had died and eight patients (eight hips) had been lost to follow-up. A total of 14 fractures in 14 patients had occurred. In ten hips, the femoral component had to be revised and in four the fracture was treated by open reduction and internal fixation. The cumulative incidence of peri-prosthetic femoral fracture was 1.6% (95% confidence interval 0.7 to 3.8) at ten years and 4.5% (95% confidence interval 2.6 to 8.0) at 17 years after the primary THR. There was no association between the occurrence of fracture and gender or age at the time of the primary replacement.

Our findings indicate that peri-prosthetic femoral fracture is a significant mode of failure in the long term after the insertion of an uncemented CLS Spotorno stem. Revision rates for this fracture rise in the second decade. Further research is required to investigate the risk factors involved in the occurrence of late peri-prosthetic femoral fracture after the implantation of any uncemented stem, and to assess possible methods of prevention.