Hip problems in dogs are an all too common problem, with some issues being more serious than others. For the dog with severe hip dysplasia or a growth deformity of the hip, the vet may recommend a femoral head osteotomy (FHO surgery). But what is this procedure, which dogs are good candidates, and how successful is the outcome?

What is FHO and How Does it Work?

FHO stands for 'femoral head osteotomy', or in plain speaking the surgical removal of the top part of the thigh bone which sits in the pelvis. The aim of surgery is to remove the source of pain (bone rubbing against bone) and form a new muscular hip joint which is pain-free. So how does this work?

A Healthy Hip

To understand how FHO surgery works, let's first look at the healthy hip. The hip is a ball-and-socket joint with the femoral head forming the ball, with a cup in the pelvis being the socket. This joint is engineered to contain joint fluid so everything moves as sweetly as a ball-bearing in ball-bearing race.

A Diseased Hip

A dog with hip dysplasia or another form of damage to the bone, doesn't move smoothly. Instead, the rough or misshapen femoral head knocks and clunks with each step. This causes inflammation and it's this that causes pain. In short, bone banging against bone hurts!

A FHO Hip

Femoral head osteotomy works by physically removing the top part of the thigh bone (femur) so that it no longer bumps into the pelvis. With the bone-on-bone contact gone, so is the pain.

What happens during the recovery period is that the strong muscles of the hip step up and form a 'muscular sling'. The equivalent of a muscular cushion forms between the top of the thigh bone and the pelvis, whilst the powerful thigh muscles take up the slack to move the thigh bone when the dog takes a step. Hey presto! A good-as-new pain free hip.

What are the Reasons for Performing an FHO?

If a dog is in pain because of poor anatomy of the bony part of the hip joint, then FHO surgery may help. Some of the more common reasons this surgery is undertaken are listed below.

• Hip Dysplasia: The word 'dysplasia' refers to abnormal growth of the bone, which causes pain and impairs quality of life.
• Fracture of the Femoral Neck: Road traffic accidents can result in the femoral head snapping off the top of the thigh bone. Surgical pinning or plating may offer an answer, but where there is too much damage or the cost of specialist surgery is prohibitive, then FHO is a good solution.
• Legge-Perthe's Disease: This condition affects the hip joints of small breed puppies. The blood supply to the hip shuts down too early, so the femoral head is weak and crumbly.
• Hip Dislocation or Subluxation: Some hip dislocations are difficult to put back into place or pop out again once the dog stands on the leg. Removing the femoral head allows for pain-free movement in cases where surgery to permanently toggle the hip in place isn't possible.
• Severe Arthritis: Bone that is remodelled due to arthritis, causes a great deal of pain. Remove the bone and this gives some measure of comfort.

Which Dogs might Benefit from FHO Surgery?

Femoral head osteotomy is a good solution for many dogs with long term hip pain. However, it's not suitable for everyone. The dogs that do best are:

• Smaller dogs, under 50 lbs body weight
• Lean dogs in good body condition
• Fit dogs

This is due to the downward forces through the hip joint being greater, the bigger the dog. If the dog is heavy then the compression on the muscular cushion in itself causes discomfort. However, for smaller, lighter dogs this is not a worry and they do well.

Also, because the joint is muscular, the fitter the dog the more they benefit. Whereas an unfit dog with a lot of muscle wastage, may struggle to rehabilitate and get back on their paws after the op.

This doesn't mean that vets never perform FSO surgery on large or overweight dogs, but they will be extra careful to discuss the risks and benefits so the owner can make an informed decision.

What are the Alternatives to a Femoral Head Osteotomy?

The gold standard for large, adult dogs is total hip replacement surgery. This successful operation gives the dog a better-than-new hip and the gift of great mobility. For pups at high risk of developing hip dysplasia, the triple pelvic osteotomy may be the answer. And if surgery isn't an option then physiotherapy, pain relief, and joint supplements help make the most of a bad deal.

Post Operative Care

For the first few days after FHO surgery it is surgical sutures that support the hip joint. Thus, it's important the dog rests and doesn't over exert themself. For the first week, rest and recuperation is what the doctor ordered.

Once the skin sutures are removed, the dog enters a rehabilitation phase. This lasts for roughly six weeks. The aim is to slowly build up the dog's muscles with gentle exercise so that they become strong enough (at around the six week point) for normal play.

Good activities during the recovery start with lead walking, following by walking up hills or stairs, or indeed walking through water. But avoid sudden twisting and turning movements as these may wrench the muscles and set things back. Once the dog has been signed off by the vet, this is the time to get more energetic.

What to Expect after an FHO

Femoral head osteotomy helps to control pain, but the dog may remain slightly lame after surgery. This is because a piece of bone is removed, leaving one leg fractionally shorter than the other side. This mild lameness is mechanical (due to a shortened leg) rather than due to discomfort.

What are the Possible Complications of FHO Surgery?

Complications of FHO surgery are rare, but no procedure is entirely without risk. Uncommon complications include:

• Boney spurs: If the femoral head comes away leaving a spur of bone, this can grate and cause pain. To avoid this the vet takes postoperative radiographs to ensure everything is smooth.
• Nerve damage: The major nerve to the back leg hooks around the hip joint. It is theoretically possible to damage this nerve during hip surgery, causing paralysis.
• Infection: Any surgical can become infected, especially if the dog licks the op site.

In short, for small dogs in constant hip pain then FHO is a good option. The best placed person to assess the dog is their vet, who will be able to talk through the pros and cons for each case, in order to get the pooch back on their paws.

 

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