Custom acetabular prosthesis for total hip replacement: A case report in a dog with acetabular bone loss after femoral head and neck ostectomy

Authors: 
Castelli E, Schmierer PA, Pozzi A.
Vet Surg. 2019 Aug 23. doi: 10.1111/vsu.13303.

OBJECTIVE: To describe the application of a custom acetabular prosthesis (CAP) for total hip replacement (THR) in a dog 20 months after femoral head and neck ostectomy (FHNO).

STUDY DESIGN: Case report.

ANIMAL: A 10-year-old, male, castrated, Labrador retriever with progressive lameness and pain after FHNO.

METHODS: Acetabular bone stock was assessed as insufficient for conventional THR, so a biflanged CAP was designed and three-dimensionally printed in titanium to bridge the bone defect. The CAP had a porous surface for long-term biologic fixation on the backside and was anchored to the ilium and ischium with screws. A polyethylene cup was cemented into the CAP, and a bolted cementless femoral stem was inserted.

RESULTS: The loss of the conventional anatomic landmarks complicated intraoperative orientation and led to eccentric reaming and 5-mm malalignment of the CAP. Reduction of the prosthetic joint was difficult because of periarticular fibrosis, loss of functional muscle length, and thickness of the CAP, and intraoperative shortening of the stem neck was required. Postoperative complications included sciatic neurapraxia, which resolved with time and conservative management. Absence of pain and improvement of range of motion were observed at clinical examination 12 months after surgery; however, moderate hind limb lameness persisted due to muscle tension. No evidence of implant loosening was noted on radiographs acquired 24 months after surgery.

CONCLUSION: Femoral head and neck ostectomy with poor functional outcome was ameliorated by using a CAP in this dog.

CLINICAL SIGNIFICANCE: Use of a CAP can be considered to treat acetabular defects in dogs.

Small animal: