FHO (femoral head ostectomy) is a surgical procedure that removes the ball-shaped top of your dog’s thigh bone where it meets the hip socket. Rather than repairing the joint, the surgery eliminates it entirely. Over the following weeks, scar tissue forms between the remaining femur and the pelvis, creating a “false joint” that allows pain-free movement without bone-on-bone contact. It’s one of the most common orthopedic surgeries in veterinary medicine, particularly for smaller dogs.
How the Surgery Works
A normal hip joint is a ball-and-socket design: the round head of the femur (thigh bone) sits snugly inside a cup-shaped socket in the pelvis called the acetabulum. When disease or injury damages this joint, every movement grinds damaged bone surfaces together, causing significant pain.
During FHO, the surgeon cuts away the femoral head and neck, removing the “ball” from the equation entirely. With that bone gone, the body does something remarkably useful on its own. Dense fibrous scar tissue gradually fills the gap between the femur and pelvis, forming a cushion that acts as a functional joint. This false joint doesn’t have the same range of motion as a natural hip, but it eliminates the primary source of pain and restores enough mobility for most dogs to walk, run, and play comfortably.
Conditions That Lead to FHO
Veterinarians recommend FHO for several hip conditions where the joint is too damaged to salvage:
- Legg-Perthes disease: Most common in toy and miniature breeds, this condition causes the bone inside the femoral head to lose its blood supply and begin dying at a young age. The bone collapses, causing severe pain. FHO removes the deteriorating bone entirely.
- Hip fractures: When a break involves the hip joint itself and can’t be repaired surgically, whether due to the fracture pattern or financial constraints, FHO offers a reliable path to pain-free mobility.
- Hip luxation or dislocation: Sometimes a hip pops out of its socket from trauma or severe dysplasia, and it can’t be put back with manipulation or other methods. Surgical repair of luxations can be expensive and isn’t always successful, so many owners of small dogs choose FHO instead.
- Severe hip arthritis: In end-stage arthritis, the protective cartilage on both the femoral head and the socket wears away completely. Every movement becomes painful bone grinding against bone. Removing the femoral head stops that contact.
Which Dogs Are Good Candidates
FHO works best in dogs weighing under about 70 pounds. Smaller, lighter dogs put less stress on the false joint that forms after surgery, and their muscle and scar tissue can more easily support the limb. In research looking at outcomes, dogs under 15 kg (about 33 pounds) consistently did well, while results became more mixed for dogs over 25 kg (about 55 pounds).
That doesn’t mean FHO is never performed on larger dogs. When total hip replacement isn’t an option, FHO can still provide meaningful pain relief for bigger breeds. But the functional outcome tends to be better the lighter the dog is, because less weight needs to be supported by scar tissue alone.
What to Expect After Surgery
Most dogs show improvement surprisingly quickly. In one study published in the Journal of the American Veterinary Medical Association, lameness scores dropped significantly within 4 to 6 weeks after surgery, regardless of whether the original problem was a sudden injury or a chronic condition like arthritis. That said, the research also found that dogs after FHO generally don’t return to completely normal movement patterns. Most reach a functional level where they’re comfortable and active, but subtle differences in gait often remain.
A retrospective study of 132 dogs that underwent the procedure found that 84% had some upward displacement of the femur on the surgical side, 75% had measurable muscle atrophy in the affected leg, and 74% had a restricted range of motion compared to a healthy hip. About 32% showed discomfort during passive movement of the joint. These numbers sound alarming, but many of these dogs were still functionally comfortable in daily life. The surgery trades a perfect joint for a pain-free one.
Recovery and Rehabilitation
Rehabilitation is not optional after FHO. The quality of the outcome depends heavily on how consistently your dog does physical therapy in the weeks following surgery. Without it, the leg muscles weaken, scar tissue forms too tightly, and your dog may avoid using the leg altogether.
Days 1 to 3
Gentle passive range of motion exercises begin almost immediately. This means slowly and carefully moving the leg through its natural arc while your dog is resting. The goal is to prevent stiffness from setting in before the healing process even gets started.
Weeks 1 to 2
Apply moist heat to the hip for about 10 minutes before each exercise session to relax the muscles. Gentle massage around the thigh and hip area improves blood flow. Continue daily passive range of motion work. Cookie bends, where you use a treat to guide your dog’s nose toward each side of their body, encourage gentle stretching and help build core balance.
Weeks 3 to 6
This is when active strengthening ramps up. Sit-to-stand exercises done with your dog’s side against a wall engage the rear legs. Controlled stair climbing on low steps builds strength gradually. Walking on gentle slopes improves balance and weight-bearing confidence. Cavaletti poles (bars set a few inches off the ground) teach your dog to lift their legs deliberately. Weaving through cones or furniture improves coordination. Standing on a cushion or balance pad and encouraging gentle side-to-side weight shifts helps rebuild stability.
Week 6 and Beyond
Water therapy becomes especially valuable at this stage. Swimming and underwater treadmill work build muscle with minimal joint stress, improving both strength and range of motion simultaneously. Wobble boards and physio balls challenge your dog’s balance further. Earlier exercises should continue alongside these advanced activities to maintain the gains already made. Low-impact exercise like swimming remains ideal for long-term muscle tone even after the formal rehab period ends.
FHO vs. Total Hip Replacement
Total hip replacement (THR) is the other major surgical option for severe hip problems. It replaces both the ball and socket with prosthetic components, restoring something much closer to normal joint mechanics. Dogs that receive THR typically return to full activity without lameness.
The tradeoffs are significant. THR costs substantially more, requires a specialist surgeon, and carries its own surgical risks. FHO is simpler, more widely available, and less expensive. But biomechanical studies show that legs treated with FHO produce significantly lower forces during walking compared to normal legs, meaning the limb never quite works as efficiently as it did before.
One important consideration: if FHO doesn’t produce a satisfactory result, converting to a total hip replacement later is extremely difficult. Extensive scar tissue and muscle contracture make it hard to fit and stabilize a prosthetic joint. Anecdotal guidelines suggest THR becomes inadvisable if more than 6 months have passed since the FHO. So if your dog is a potential candidate for both procedures, that decision is best made upfront rather than treating FHO as a trial run.
Cost of FHO Surgery
The national average cost for FHO is approximately $2,629, with a typical range of $2,059 to $4,546. The price varies based on the complexity of the case, your geographic region, and the experience level of the surgeon. Post-surgical rehabilitation adds to the total, particularly if you use a professional canine rehab facility for water therapy or guided exercises. Even so, FHO is generally far less expensive than total hip replacement, which can run well above $5,000 and sometimes closer to $10,000.