Legg Calve Perthes Disease
Overview
Legg Calve Perthes is a disease of the femoral head (the “ball” structure of the large leg bone that connects into the hip), and has many “aliases” (eg aseptic necrosis of femoral head, avascular necrosis of femoral head).
The problem stems from an interruption in the blood supply to the head of the femur (the large long bone in the hind leg) which forms the “ball” portion of the hip's ball and socket joint. When starved of blood supply, portions of the bone begin to die and the cartilage that line the hip joint collapses. This results in a painful, ill-fitting hip joint. Initial symptoms tend to occur between 5-8 months of age. Unfortunately, without treatment, the condition will progress to irreversible arthritis, hip pain, shrinkage of muscles and ongoing lameness.
Predispositions
Small breed dogs e.g. Terriers and Toy breeds
Breeds commonly affected:
- Australian terrier
- Bichon frise
- Boston terrier
- Cairn terrier
- Chihuahua
- Cocker spaniel
- Dachshund
- Fox terrier
- Jack Russell terrier
- Miniature pinscher
- Miniature schnauzer
- Pekingese
- Pomeranian
- Poodle
- Pug
- Scottish terrier
- Silky terrier
- West highland white terrier
Cause
While trauma to the hip can occasionally be the cause of the disruption in blood supply, most cases are thought to be due to genetics.
Signs
- Lameness that progresses over several weeks
- Non-weight-bearing on the affected hind leg
- Pain
- Muscle loss
Diagnosis
A ongoing history of hindlimb lameness in a small breed puppy is highly suspicious of a diagnosis. X-rays confirm the appearance of an affected femoral head and hip joint.
Management
Medical therapy may be recommended for mild cases of lameness and where there are very few findings on X-rays.
Surgery is recommended for all other cases and those that don’t respond to medical therapy. Surgical options include a femoral head and neck osteotomy (FHO) or a total hip replacement.
Femoral head and neck osteotomy (FHO)
The surgical removal of the affected femoral head and neck to develop a false joint that is supported by scar tissue and surrounding muscles. This may result in a shorter leg on the affected side.
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Total hip replacement (THR)
A total hip replacement involves the surgical replacement of the affected femoral head, neck, and acetabulum with orthopaedic prostheses.
Physical therapy
Physical therapy is recommended following surgery to aid in the recovery and ensure optimal mobility. Physical therapy may include passive range of motion exercises and/or hydrotherapy. Having the pet walk on the affected leg as soon after surgery will help reduce muscle weakening and put them on track for a speedy recovery. You should expect to see weight-bearing within 1-2 weeks after surgery.
Home care
It is important the pet maintains a healthy weight to prevent added pressure on the joint.
Prognosis
Most small to medium size dogs do well and return to pain-free function following surgery.
Medically managed pets will continue to have a deformed femoral head that may result in ongoing joint discomfort and progress to osteoarthritis later in life.