Juvenile pubic symphysiodesis associated with pectineus myectomy for treatment of hip dysplasia in dog

Resumo

Background: Hip dysplasia (HD) is the most common non-traumatic orthopedic disease in large breed dogs. Treatment is chosen according to the severity of the condition, the age of the dog and the involvement of osteoarthritis (OA). For puppies up to 20-weeks-old, surgical treatment by the juvenile pubic symphysiodesis (JPS) technique can be performed. This procedure promotes the ventrolateral rotation of the acetabulum over the femoral head, which improves hip joint congruence and stability. The objective of this study is to report the case of a young dog with HD treated with JPS and pectineus myectomy. Clinical and radiographic outcomes were assessed for up to one year after surgery.

Case: A 17-week-old Saint Bernard puppy was attended at the University Veterinary Hospital showing abnormal weight bearing and lameness in pelvic limbs, without history of previous trauma. On orthopedic examination, there was a marked hypotrophy of the pelvic limb muscles, severe pain and laxity in the hip joints, and positive feature in the Ortolani test. The hip joint subluxation angle (SA) and reduction angle (RA) were measured. A radiographic study was carried out to evaluate the hip joints and measure the Norberg angle (NA), distraction index (DI), acetabular angle (AA) and dorsal acetabular rim angle (DARA). The 20-week-old dog underwent surgical treatment by JPS technique. A ventral surgical approach to the pubis was performed and the pubic symphysis was cauterized with electrocautery. Partial pectineus myectomy technique was also performed. Drug therapy and restriction of physical activities were indicated in the early postoperative. The dog was evaluated by clinical and radiographic examinations at 4 months and 1 year after the surgical procedure. In the reassessment after 4 months of surgical treatment, the patient showed improvement in clinical signs, with mild lameness and absence of painful sensitivity in the movement of the hip joints. Radiographically, hip joint incongruity was observed, but with progressive improvement in the values of the measured variables. In the clinical examination 1 year after the procedure, the dog showed satisfactory weight bearing with slight lameness in pelvic limbs in the running gait. There was improvement in the thigh muscles and no painful signs were observed in the hip joints, but a positive result was detected in the Ortolani test. In the radiographic examination, bilateral articular incongruity was still observed, however, there was a mild improvement in the coverage of the acetabulum over the femoral head. The measured angles and indices showed favorable results regarding the recovery of hip joint stability and proper development.

Discussion: Studies evaluating the JPS technique for the treatment of HD have shown to be a relatively simple and effective procedure, which allows altering the acetabular coverage, reducing the development of HD and the progression of OA. The need for an early diagnosis of this condition is essential, so that the JPS technique can be used in young dogs and offer effective results. In the present report, in the late postoperative period, the dog showed improvement in clinical signs, with favorable weight bearing and ambulation in pelvic limbs, recovery of limb muscles, absence of pain in the hip joints and decrease in RA and SA. Radiographically, the reduction in joint subluxation, improvement in acetabular coverage over femoral heads, increase in NA and AA, reduction in DI and DARA are evidence of the favorable outcome of ventrolateral rotation of the acetabulum after surgical treatment. The surgical technique used was effective, which enabled the dog to recover the functional use of the pelvic limbs and improve the quality of life.

Keywords: hip dysplasia, juvenile pubic symphysiodesis, hip joint, osteoarthritis, dog.

Título: Sinfisiodese púbica juvenil associada à miectomia do pectíneo
para tratamento de displasia coxofemoral em cão

Descritores: displasia coxofemoral, sinfisiodese púbica juvenil, coxofemoral, osteoartrite.