We analysed periprosthetic bone mineral density (BMD) by dual-energy X-ray absorptiometry (DEXA) in patients after uncemented total hip arthroplasty (THA) (press-fit CLS Spotorno stem). Only patients with good clinical outcome (Merle d‘ Aubigne score > 12) were included to obtain normative data for regular bone response.

Two separate studies were performed: A prospective longitudinal study over a time period of 7 years (group A) (n = 26 patients: 12 women, 14 men) and an additional cross-sectional study, mean follow-up13 years (10 to 15 years) (group B) (n = 35 patients: 18 women, 17 men). Regions of interest were defined according to Gruen (ROI 1–7) and as netto average ROI (NETAVG) for the periprosthetic femoral bone. After the initial remodelling process, BMD at 1 year was compared to the 7-year (longitidinal) and to the 13-year (cross-sectional) follow-up values of the affected limb to determine long term periprosthetic changes of bone mineral density.

The longitudinal study (group A) showed BMD values of 91.1% and 92.8% after 1 year, 91.2% and 90.2% after 7 years compared to the initial post-operative values for women and men, respectively. ROIs around the proximal stem (ROI 1 and 7) showed the lowest absolute values and decreased most during follow-up (ROI 1: 80.7% and 84.5%, ROI 7: 71.1% and 75.5% after 7 years, for women and men respectively). In the cross-sectional study (group B) BMD was determined 89.1% and 87.8% after 13 years compared to the initial values of group A for women and men. Distribution of BMD in ROIs 1-7 (group B) showed no significant changes compared to the 1 year and 7 year results of group A. The results reflect normative long term changes in the periprosthetic bone after implantation of THA in defined ROIs of a well functioning tapered corundum-blasted titanium stem.

We studied the effects of irradiation on the reintegration of autologous osteoarticular grafts over a period of 24 weeks in a canine model. In 16 foxhounds the medial femoral condyle was resected, irradiated and immediately replanted. In the control group resection and replantation were performed without irradiation. Reintegration was assessed by macroscopic analysis, histology, radiography and gait analysis.

Reintegration was equal at 12 weeks, but significantly inferior in the irradiated group after 24 weeks with delayed bone remodelling. The articular cartilage showed modest degeneration. Conventional radiography and histology showed corresponding changes. Limb function was adequate but the gait was inferior in the treated group.

We report our results using three different threaded acetabular components (Mecring A, Mecring B and Weill) in 715 hips with a follow-up of between one and ten years (median: 99.1, 56.5, 38.3 months, respectively). All cups were implanted with one type of cementless stem.

The clinical results were good or acceptable in about 70% of the hips, but signs of loosening with radiolucency and/or migration were found in 10.1%. Radiological evidence of loosening did not correlate significantly with the clinical outcome. Pain was not a reliable indicator of loosening and its absence sometimes allowed severe osteolysis to develop. Twenty-five hips were revised (3.5%) for aseptic loosening of the acetabular component. Kaplan-Meier estimates of the cumulative rate of failure showed a rapid increase five years after the initial operation, but no significant correlation with gender, age or weight.

The high rate of failure indicates that further use of these acetabular components cannot be recommended. Annual radiographs are required to assess osteolysis even if the patients are free from pain.