Classification of acetabular changes in osteoarthritis: a histological and radiological analysis of 122 consecutive drill biopsies routinely taken during THA

Histological evaluation of acetabular bone quality during revision hip arthroplasty

PURPOSE

Aim of this study was to evaluate acetabular bone vitality during revision hip arthroplasty and to compare the bone quality between revision and primary acetabular arthroplasty.

METHODS

During primary and revision total hip arthroplasty surgeries, biopsies were taken from the acetabulum after reaming. The samples (osteochondral cylinders of approximately ⩽1 cm long and 3 mm thickness), after removing the mineral component, were cut longitudinally with a thickness section of 5 µm and colored with hematoxylin-eosin dichromic dye and then evaluated histologically by optical microscopy with 40× magnification. Preoperative radiographs were evaluated.

RESULTS

According to inclusion and exclusion criteria, 14 patients formed the revision group patients (mean age: 67.9 years, average time before revision 8.8 years, SD ± 7.06) and 5 patients formed the control primary group (mean age: 61.4 years). The bone quality of the revision group was generally poorer than the primary group, while similar vitality and bone quality has been found between septic and aseptic group. Variables such as age, gender and BMI did not significantly contribute to define bone quality classes.

CONCLUSIONS

The study confirms the differences in quality and bone vitality between cases and controls and the necessity to find strategies to improve the osteointegrative processes in revision arthroplasties.

The histology around the cemented Müller straight stem: A post-mortem analysis of eight well-fixed stems with a mean follow-up of 12.1 years

The aim of this study was to obtain detailed long-term data on the cement-bone interface in patients with cemented stems, implanted using the constrained fixation technique. A total of eight stems were removed together with adjacent bone during post-mortem examinations of patients with well-functioning prostheses. Specimens were cut at four defined levels, contact radiographs were obtained for each level, and slices were prepared for histological analysis. Clinical data, clinical radiographs, contact radiographs and histological samples were examined for signs of loosening and remodelling. The mean radiological follow-up was 9.6 years and all stems were well-fixed, based on clinical and radiological criteria. Contact radiographs revealed an incomplete cement mantle but a complete filling of the medullary canal for all implants. Various amounts of polyethylene particles were evident at the cement-bone interface of seven stems, with no accompanying inflammatory reaction. Cortical atrophy and the formation of an 'inner cortex' were confirmed in six of eight stems by contact radiographs and histology, but were only visible on two clinical radiographs. Our results confirm that a complete cement mantle is not essential for the survival of Müller straight stems into the mid term, and support our hypothesis that no benefit to long-term survival can be expected from modern cementing techniques.