Hip Dysplasia
Hip dysplasia is a complex orthopaedic pathology that leads to joint inflammation and arthritis. The pathology is characterised by early joint subluxations due to joint laxity during the growth followed by bone remodelling (shallow acetabulum and flattening of the femoral head) and arthritis. In the adult age, severe arthritis results in discomfort, lameness, and disability.
Normal Hip, The femoral head is sitting within the acetabulum.
Joint laxity, the femoral head is not sitting within the femoral head.
Joint laxity leads to dorsal subluxation of the femoral head.
Developing of osteoarthritis and bone remodelling.
Clinical Signs
Stiffness, exercise intolerance, lameness on one or both pelvic limbs, bunny hopping when running, difficulty to stand after exercise, reluctance to walk, run, jump, or climbing stairs are the most common clinical signs.
Moreover, older patients affected by chronic degenerative hip joint disease prefer sitting rather than standing. Muscle atrophy (weakness) on both pelvic limbs (back legs) and muscle hypertrophy (increased muscle tone) on the thoracic limbs (front legs) are likely clinical finding.
Diagnosis
Diagnosis is based on clinical signs, physical examination, and XR.
Radiographic examination and clinical assessment under general anaesthetic are essential to establish the final diagnosis, and to plan a correct treatment plan.
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Adult patient with normal hips
Adult patient affected by severe arthritis and bone remodelling
Treatment
Medical Management
Medical management of hip dysplasia is mainly based on nutritional, (slim body weight), physiotherapy, joint supplements and painkillers. The aim of these treatments is to increase the quality of the life of the patient improving leg movement and slowing down the degenerative process. However, medical managements are considered palliative treatments.
Surgical Management
In young patients, procedures such as Double Pelvic Osteotomy (DPO) or Juvenile Pubic Symphysiodesis (JPS) are performed to reduce the hip subluxation changing the coxo-femoral joint angle. The aim of those procedures is to increase the dorsal coverage of the femoral head by the acetabulum reducing the subluxation. In adult age or in young puppy affected by severe laxity, Total Hip Replacement is the treatment of choice. However, Femoral Head and Neck Excision could be considered as a salvage procedure to relieve pain in patients that are good surgical candidate.
Juveline Pubic Symphysiodesis (JPS)
The surgery is performed in patients younger than 5 months of age (ideally 3 to 5 months of age) and involves the application of electrosurgery on the ventral pelvis (pubic symphysis)
This results in slower growth of the ventral pelvis and normal growth of the dorsal pelvis. As the patient growth progress, the dorsal pelvis grows in a slightly lateral direction resulting in better coverage of the femoral head.
The patient selection is not based only on the patient age but also on the radiographic findings, patient with mild to moderate joint laxity are the ideal candidates.
Duplice Pelivc Osteotomy (DPO)
Whereas the JPS is performed on patient younger than 5 months of age, the DPO is performed in patients younger than 12 months of age (ideally 5 to 8 months) in the absence of arthritis.
The DPO includes two bone cuts: one on the wing of the Ilium and a second one on the pubis. A third incision could be performed on the Ischium to release the sacrotuberous ligament. The ilium is rotated in an angle of 20-25-30 degree according to presurgical planning based on XR and this is fixed at this angle with a pre-countered plate. Sometimes, extra plates or wire can be placed on the ventral part of the ileum to strengthen the implants.
Case Studies
