Use of clinical and computed tomography findings to assess long-term unsatisfactory outcome after femoral head and neck ostectomy in four large breed dogs

Femoral head and neck ostectomy (FHNO) is a salvage surgical procedure intended to eliminate hip joint laxity associated pain in the immature dog, or pain due to secondary osteoarthritis in the mature dog. The outcome of the procedure is associated with the size of the dog but the cause of a generally poorer outcome in larger breeds has not been determined. The objective of this study was to assess the long-term results of FHNO associated with unsatisfactory functional outcome by means of clinical examination and computed tomography (CT) scanning. Four large mixed breed dogs underwent FHNO in different veterinary clinics. Clinical and CT scanning evaluations were carried out long time after the procedures had been done. Hip pain, muscle atrophy, decreased range of motion and chronic lameness were observed at clinical examination. Extensive remodelling, unacceptable bone-on-bone contact with bony proliferation involving the femoral neck and acetabulum, but also excessive removal with bone lysis were observed by CT scanning. Revision osteotomy was performed in one dog. Deep gluteal muscle interposition was used, but no improvements were observed postoperatively. This is the first report on the evaluation of three-dimensional CT reconstructions of the late bone remodelling associated with poor clinical outcome in large dogs. The study shows that FHNO could lead to severe functional deficits in large breed dogs. An extensive follow-study is necessary to more accurately determine the frequency of such complications.