Single-stage revision using an uncemented, porous-coated, anatomic endoprosthesis in two dogs: case report

To describe the clinical and radiographic features of septic and aseptic failure of two femoral endoprostheses and their successful revision. Case report. Two skeletally mature male research dogs. An uncemented porous-coated anatomic (PCA) endoprosthesis was implanted in a single-stage revision procedure after thorough debridement and lavage of the femoral canal. An autogenous cancellous bone graft was used in dog 2 (aseptic loosening). Serial clinical and radiographic examinations were performed postoperatively. The dogs were euthanatized 1 year (dog 1) and 2 years (dog 2) after revision surgery, and necropsy was performed. High-resolution contact radiographs and histopathologic evaluation of femoral sections were obtained. The cause of implant failure was septic loosening in dog 1 and aseptic loosening in dog 2. In both dogs, clinical function returned to normal after revision. Serial radiographic assessment after revision documented disappearance of the bone pedestal and the periprosthetic lucency. Cancellous hypertrophy seen adjacent to the proximal porous-coated region of the implants provided radiographic evidence of bony fixation. Histological evaluation of femoral sections documented successful implant integration with bone and fibrous tissue. Revision with an uncemented implant in a single-stage procedure was successful in the two dogs described in this report. This report provides a detailed description of the clinical course and serial radiographic assessment of septic and aseptic loosening of two femoral endoprostheses. Single-stage revision is a potential treatment for either condition as demonstrated by the successful outcome in these two dogs.