Hip dysplasia is a common term for the separation of the two pieces of the ball and socket joint that makes up the hip, the acetabulum (socket) & femoral head (ball). A femoral head ostectomy (FHO) is a surgical procedure that removes the head and neck from the femur. FHO surgery is performed to alleviate pain.
Hip Anatomy:
The hip joint in a normal dog is composed of two bones that form a ball and socket joint:
- The femoral neck or head comprises the ball portion
- The acetabulum, a cup in the pelvis, forms the socket portion.
- The ball and socket are held in position by a ligament called the capital ligament.
Additional support is provided by the upper rim of the acetabulum and a fibrous capsule that encloses the whole joint, in conjunction with muscles which provide the majority of support.
While hip dislocation is usually due to trauma and in many cases can simply be manually replaced, hip dysplasia is more often due to poor genetics. Patients may present with lameness after exercise, have difficulty with stairs, be unable to sit or stand fluidly, and often carry more of their weight forward creating a mildly hunched stance.
Dysplasia & Diagnosis:
Physical Exam: It is possible for your veterinarian to feel if a hip is feels lose or arthritic, and if severe enough, they may even feel the hip “pop” in and out of the joint.
Radiograph of a Patient with Hip Dysplasia
Radiographs: X-rays will help to clearly diagnose hip dislocation and displacement, as well as:
- Assess additional damage to the joint.
- Possible cause of the displacement.
- Identify if the acetabulum is shallow, allowing the femoral head to slip out of place.
- Determine if surgical correction is required.
- Show the development of any arthritis or bone spurs, which can cause arthritis.
The Femoral Head Ostectomy (FHO):
A femoral head ostectomy (commonly referred to as FHO surgery) is the most commonly performed surgery to correct hip dysplasia.
- During surgery, the femoral head, the ball portion of the joint is removed to alleviate the pain of bone rubbing on bone.
- The capital ligament is removed to eliminate painful tearing of the ligament.
- The joint capsule is removed to alleviate painful stretching of the capsule.
- After surgery, the joint heals as a “false” joint.
- The capsule connecting the two bones is still in place, as are the muscles that support the joint.
Radiograph of a patient after FHO surgery