Femoral head ostectomy
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. It is a salvage procedure, reserved for condition where pain can not be alleviated in any other way. It is common in veterinary surgery. Other names are excision arthroplasty of the femoral head and neck, Girdlestone's operation and femoral head and neck ostectomy.
FHO was first described by Gathorne Robert Girdlestone(1881–1950) in 1945. He originally designed the procedure for treating tuberculosis and other disorders of the hips. This has led to the procedure also being known as a "Girdlestone operation". Other surgeons added various modifications to the procedure to improve recovery and outcomes.
FHO was first described in veterinary science in 1961 by J.S.A. Spreull.
Indications in veterinary science 
Small breeds of dog, cats and small horses, donkeys and ponies have all had the procedure performed successfully. Hip dysplasia, an extremely painful congenital condition found in many dog breeds and some cats, is an example of such a condition where this procedure may be used. It is also performed in cases of trauma where the head of the femur is badly broken or severed, or in response to other diseases of the hip bone, such as Legg-Calve-Perthes' disease. It is sometimes the procedure of last resort when other methods have failed and or sepsis of the joint has occurred, but it can be indicated when the hip joint is severely affected or if arthritis In the joint is serious enough. It can also be indicated in small animals with pelvic fractures, particularly fractures of the acetabulum (socket of the pelvis).
The procedure exposes the head section of the femur bone (the ball of the ball and socket joint), and then the head is removed using a small saw or a bone hammer and chisel. Rarely both sides are done in one operation, most times one side is done and allowed to heal before the other side is done.
Unlike most other hip surgeries, the head of the femur is not replaced, but is allowed to heal and develop its own fibrous scar tissue so that the joint is no longer bone−to-bone, a pseudoarthrosis (also called a "false joint"). The neck of the femur is usually removed at the same time as the head. This prevents the post operative complication of bone rubbing on bone and continued pain. This has led to the procedure often also called "Femoral head and neck ostectomy".
Animals who have had FHO surgery are required to maintain a lower weight throughout their lives to compensate for the loss of skeletal integrity, and typically of excellent functional outcomes with appropriate physical therapy.
Other species 
Small horses and ponies can have an ostectomy without an osteotomy of the greater trochanter. As a salvage procedure, this is usually performed in those animals which have the specific injury of a fracture of the capital physis. These patients would not return to function as a riding horse and the procedure may be performed for those animals involved in breeding, milking, and being kept as companion animals.
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- Spreull, R.S.A (1961). "Excision Arthroplasty as a method of treatment for hip diseases in the dog". Veterinary Record 73: 573.
- Rawson EA, Aronsohn MG, Burk RL (2005). "Simultaneous bilateral femoral head and neck ostectomy for the treatment of canine hip dysplasia". J Am Anim Hosp Assoc 41 (3): 166–70. PMID 15870250.
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