Causes: The mode of inheritance as demonstrated by breeding studies in Westies is complex and probably polygenic but it is suggested that there is a an autosomal recessive trait with incomplete penetrance. 

Symptoms: Typically clinical signs consist of  lameness in one leg with deformity of the hip joint occurring  in young dogs  between 4 to 11 months old. Sometimes, the dog may show at first some irritability.  Pain ranges from mild to severe. In 15% of cases, both hips are affected. There may be substantial atrophy of the muscles in the affected area. 

Diagnosis: The diagnosis is made by clinical signs and confirmed by radiographs. Some veterinarians also advocate the use of biopsies. Sometimes, x-rays taken early in the course of the disease may appear normal. That is why it is often necessary to have them repeated in 3 to 4 weeks to  see the bony changes since they occur slowly. 

Treatment:  Treatment varies depending on the severity of the condition.  Some dogs have only mild forms of this condition and require no treatment or only enforced rest in crate or in small exercise pens.  In some cases, immobilisation of the affected limb in an Ehmer sling is preferred. In other dogs, pain is severe and surgical treatment is required. Conservative treatment is less satisfactory once the necrosis has begun so that surgery is most often the method of choice. It consists in excision of the femoral head (ball portion of the hip joint) to form a  fibrous pseudo-joint which will be free from pain although range of motion and stability are decreased.

Prognosis:  The surgical treatment relieves the pain and recovery is usually quick although occasionally recovering the use of the leg can take up to a year. If the atrophy of the muscles is severe, the recovery period is longer. Physiotherapy in the form of exercises and  swimming may prove helpful.  Some pain relievers and anti-inflammatory medication may be beneficial. The long term prognosis after surgery is quite good, especially since Westies are a small breed who do not bear a lot of weight in the hip joint. It is not uncommon to see a Westie jump and run as though nothing has ever happened so that the slight residual limp is often overlooked by a casual observer. 

Prevention: To eliminate the disease in West Highland White Terriers, breeders must select animals with no family history of Legg-Calve-Perthes.  An open registry is provided by the Institute for Genetic Disease Control in Animals (GDC). The Orthopaedic Foundation for Animals (OFA) is a registry which examines X-rays of hips and certifies that they are normal.
 

Further reading:

Ackerman, L. Keeping your West Highland White Terrier Healthy.  Project TEACH Course Notes for Westie Breeders. Version 1.05  Pet Health Initiative, 1996.
 

Duff R, Campbell JR. Long Term Results of Excision Arthroplasty of the Canine Hip. Vet Rec 1977 Sep 3;101(10):181-4.

Lee R.  A Study of the Radiographic and Histological Changes Occurring in Legg-Calve-Perthes Disease (LCP) in the Dog. J Small Anim Pract 1970 Sep;11(9):621-38.

Robinson, R. Legg-Calve-Perthes Disease in Dogs: Genetic Aetiology. 33:p275-6, 1992.

Warren, DV, Dingwall JS. Legg-Perthes Disease in the Dog - a Review. Can Vet J 1972 Jun;13(6);135-7.

West Highland Anomaly Task Council, Inc. (Watch). Understanding and Reducing Genetic Disease in West Highland White Terriers, 2nd ed., 1991.
 

Useful links

http://www.westieclubamerica.com/health/leggcalveperthes.html

http://www.showdog-magazine.com/medical/legperth.htm

http://www.offa.org/ofaothr.html
 

Author: Monique Courtois
Gailuron Kennel
Revised by Dr Yves Gosselin , D.M.V.