Osseointegration of threaded acetabular cups - radiological and histological evaluation after total hip arthroplasty

Aseptic loosening of the acetabular cup component is the primary cause for complex revision surgery following total hip arthroplasty. However, the extent to which the different zones of the prosthetic contribute to successful osseointegration and how reliable this integration can be assessed using conventional radiographs remain unclear. The aim of the study was to evaluate the osseointegration of cementless threaded acetabular cups through a combination of radiological analysis and histological validation.

Eight hemipelves of body donors with cementless threaded acetabular cups were included in this study. Conventional radiographs were used to assess the specimens for existing radiolucent lines, periprosthetic osteolysis, or fractures. For histological analysis, thin sections of the acetabular cup were examined for the presence of a periprosthetic membrane, particle debris or inflammatory cells. The areas of visible contact were identified and the bone-to-implant contact (BIC) was calculated.

Radiographic analysis revealed no signs of insufficient osseointegration, osteolytic lesions, or periprosthetic loosening, in any of the specimens. Histological examination showed an average osseointegration rate of 41.84%. Bone-to-implant contact analysis showed no significant differences between different sectors or zones, or between conical and bi-conical acetabular cups.

This study highlights successful osseointegration of cementless threaded acetabular cups, with a mean survival of 18.2 years. Radiological imaging aligned closely to histological finding, confirming implant stability and long-term clinical effectiveness.