Femoral Head Ostectomy (FHO) is a surgical procedure used primarily in small to medium-sized animals to address chronic hip pain. The operation involves removing the femoral head and neck, the “ball” portion of the ball-and-socket hip joint. This action eliminates painful bone-on-bone friction caused by a damaged or diseased joint. The goal is to create a functional, pain-free limb rather than restoring the original anatomical structure, making it a “salvage” procedure.
When FHO Surgery is Necessary
The decision to perform an FHO is made when less invasive treatments have failed to alleviate severe hip discomfort. This procedure is recommended for smaller patients, typically cats and dogs under 50 pounds, because their body weight is more easily supported by the resulting false joint.
A frequent indication for FHO is severe hip dysplasia, a genetic condition where the hip joint develops abnormally, leading to instability and debilitating arthritis. The surgery also treats non-reducible hip luxation, which occurs when the joint is traumatically forced out of its socket and cannot be realigned.
Conditions Requiring FHO
FHO is also necessary for Legg-Calvé-Perthes disease, a disorder in small-breed dogs causing spontaneous degeneration of the femoral head due to lack of blood supply. Furthermore, the procedure is employed for severe, irreparable fractures of the femoral head or neck that cannot be fixed with traditional orthopedic hardware.
How the False Joint is Created
The FHO procedure involves surgically removing the head and neck of the femur, the parts that normally fit into the acetabulum or hip socket. This action removes the painful bone-on-bone contact characterizing conditions like severe arthritis or hip dysplasia.
The surgeon smooths the remaining femur to ensure no sharp edges rub against the pelvis. With the “ball” removed, the leg muscles and surrounding soft tissues initially hold the femur in place.
Over several weeks, the body naturally forms a fibrous connection, known as a pseudoarthrosis or “false joint,” in the space where the femoral head was. This scar tissue acts as a cushion between the pelvis and the remaining thigh bone, allowing movement without direct bone-on-bone friction. While anatomically different from a true joint, this new structure provides a stable and pain-free hip for most patients.
Managing Immediate Recovery
The initial post-operative period, typically the first one to two weeks, focuses on pain control and protecting the surgical site. A veterinarian will prescribe a strict pain management protocol, often including non-steroidal anti-inflammatory drugs (NSAIDs) or opioids, which must be administered exactly as directed to manage acute discomfort.
The pet must be kept in a quiet, confined space, such as a crate or small room, to prevent sudden movements that could damage healing tissues. Activity must be severely restricted; only slow, leashed walks are permitted for bathroom breaks. Jumping, running, and climbing stairs are strictly prohibited.
Incision care involves monitoring the surgical site daily for signs of infection, such as excessive redness, swelling, or discharge. Although rest is important, gentle, controlled movement is also encouraged early on, sometimes starting three to five days post-surgery. Early passive range of motion (PROM) exercises, guided by a veterinarian, help prevent overly stiff scar tissue and maintain joint flexibility.
Achieving Full Mobility
Long-term success after FHO surgery relies on a dedicated rehabilitation phase, which can last three to six months. The primary goal is to rebuild muscle mass lost due to pre-surgical disuse and post-operative rest.
Physical therapy (PT) is a major determinant of the final outcome. It often includes controlled exercises. Hydrotherapy, such as walking on an underwater treadmill, is effective because it allows for controlled movement and muscle strengthening without placing excessive pressure on the hip joint.
Maintaining an ideal body weight is paramount, as extra weight puts unnecessary strain on the newly formed pseudoarthrosis. While most pets regain good to excellent function, owners should have realistic expectations; a slight mechanical limp or reduced range of motion may remain permanently. Consistent, long-term rehabilitation ultimately determines how well the pet integrates the false joint into its active life.