Femoral Head Ostectomy (FHO)

FHO is a well-established option when the hip joint is beyond repair or when other procedures are not feasible. Specific indications include:

• Avascular necrosis of the femoral head (Legg-Calvé-Perthes disease) in small breeds
• Advanced hip dysplasia with severe arthritis in cats or small dogs who are not candidates for total hip replacement
• Irreducible or repeatedly luxating (dislocating) hip joints
• Femoral head or neck fractures, particularly in cats

In cats and dogs under roughly 50 lbs, the fibrous pseudo-joint that forms after FHO typically provides very comfortable, functional limb use. In larger dogs, total hip replacement may provide better long-term function, though FHO remains a viable option when cost or other factors make that procedure impractical.

FHO is performed under general anesthesia. The steps are straightforward but require precise technique:

• An incision over the hip exposes the joint capsule
• The round ligament holding the femoral head in the socket is cut (if still intact)
• The femoral head and neck are removed with an oscillating saw at the level of the femoral neck, leaving a smooth cut surface with no sharp edges
• The incision is closed in layers; the muscle mass that once surrounded the joint now cushions the femur against the pelvis

Over the following weeks, fibrous connective tissue fills the space and organizes into a functional false joint. Most pets use the leg within days of surgery and steadily improve over the subsequent months.

X-rays of both hips confirm the diagnosis and help the surgeon plan the osteotomy angle for a smooth cut. Pre-anesthetic bloodwork assesses organ function. Pets with hip dysplasia or long-standing arthritis sometimes have muscle atrophy, and the surgeon will note this when planning post-operative physical therapy. Fast your pet from food the evening before surgery, continue any prescribed medications unless directed otherwise, and prepare a soft, non-slip area at home for recovery. Physical therapy and range-of-motion exercises are a critical part of getting the best outcome — the team will demonstrate these techniques before discharge.

Early use of the leg is actively encouraged after FHO — motion stimulates formation of the fibrous pseudo-joint and prevents muscle atrophy. The recovery milestones:

• Days 1–7: the pet is encouraged to touch the toe down immediately; pain medication supports comfortable movement; passive range-of-motion exercises begin at home
• Weeks 2–6: leash walks increase in duration; swimming or underwater treadmill (hydrotherapy) is highly beneficial if available; incision recheck at two weeks
• Weeks 6–12: most pets are using the leg comfortably; cats often return to near-normal activity; follow-up to assess muscle mass and gait

Physical therapy exercises — particularly active range-of-motion activities like controlled walking and stair climbing (if approved) — are among the most important factors in achieving a good functional outcome.

FHO is a reliable and durable procedure with a low rate of major complications. Potential issues include infection, incomplete bone removal leading to continued pain (addressed with a revision), and temporary or permanent muscle atrophy if early mobilization is not performed diligently. In larger dogs the pseudo-joint may provide less perfect function than a healthy native hip, and some dogs show a mild gait abnormality at very high exercise levels. Cats and small dogs consistently do exceptionally well — many owners cannot tell which leg was operated on after full recovery. The surgical team provides realistic expectations based on your pet's size and pre-operative muscle condition.