Hip dysplasia
What is hip dysplasia?
Hip dysplasia is a common condition in dogs where the hip joint doesn’t form properly as they grow. The hip is a “ball and socket” joint. In a healthy hip, the ball fits snugly into the socket and moves smoothly (Figure 1). In dogs with hip dysplasia, the joint is loose and doesn’t fit together well (Figure 2). Over time, this extra movement causes wear and tear inside the joint. This can lead to pain, stiffness, and arthritis as the dog gets older (Figure 3).
Some dogs show signs when they’re young, while others may not develop obvious problems until later in life. It is helpful to understand that dogs with hip dysplasia are not born with abnormally shaped joints, rather they have a laxity in the soft tissues (basically loose joints) which allow the bone to move around more than it should, and over time this is what causes the abnormal bone shape we see on radiographs.
What is hip dysplasia caused by?
Hip dysplasia is multifactorial; a number of factors (both genetic and environmental) can contribute to its development. We know that genetics are heavily implicated, meaning it is partly inherited from the dog’s parents.
Similarly, some breeds are more likely to develop it, especially larger breeds. For this reason, a lot of research has been aimed at finding ways to identify dogs that are likely to pass on genes leading to hip dysplasia. Screening tools and hip scoring schemes such as PennHIP and OFA utilise specially positioned radiographs to provide a means of detecting hip dysplasia even in dogs that do not show obvious signs, in an attempt to discourage breeding of dogs with a genetic predisposition to it (see section on diagnosis below for more information).
Genetics aren’t alone in the development of hip dysplasia.
Other factors that can impact the severity of hip dysplasia include:
- How fast they grow – Larger dogs that grow rapidly are more likely to have hip dysplasia and show early signs
- Body weight – Overweight dogs are more likely to have problems earlier and to be more affected by the arthritis that develops as a result of hip dysplasia
- Exercise while growing – too much high-impact exercise in young puppies can increase load on the joints, especially if there is underlying laxity in the hip joints
- Nutrition – overfeeding and excess calories can exacerbate developing hip dysplasia
Figure 1: Normal “tight” hips
Figure 2: “Loose” hips typical of hip dysplasia
Figure 3: Hip dysplasia with significant secondary osteoarthritis
Consequences of hip dysplasia
Because the hip joint is loose, it doesn’t move smoothly. This causes inflammation inside the joint, damage to cartilage, and early arthritis (degenerative joint disease). As time progresses, the shape of the joint continues to change which then contributes to more arthritis and pain, but also to less stability in the joint, speeding up the inflammation, damage and arthritis. You can see how this becomes a vicious cycle.
Over time, dogs may develop:
- A “hip sway” – swaying their back end from side to side so that each hip doesn’t need to move as far when they walk
- Pain in one or both back legs
- Stiffness, especially after resting
- Difficulty getting up, jumping, or climbing stairs
- A “bunny hopping” run (hopping on both back legs at the same time instead of striding out with one at a time)
- Reduced interest in exercise
- Muscle loss in the back legs
Not only can this start to cause pain, lameness and loss of mobility, but it can also place them at an increased risk of hip dislocation, sometimes even without any traumatic cause.
How is it diagnosed?
In general, hip dysplasia is diagnosed with a combination of information from the dogs history, physical examination findings, and radiographs (X-rays) to assess how the hip joint is formed and whether arthritis is present. Because other problems (like knee injuries or spinal issues) can look similar, your vet will also rule out other causes of hindlimb pain or lameness.
In young dogs, hip laxity is present before arthritis develops, so changes are not seen on the “standard” radiographic views. In these cases, we use a combination of palpation under anaesthetic and a unique series of radiographs called PennHIP radiographs, which assess hip laxity and help to identify and characterise hip dysplasia. PennHIP radiographs require a specialised positioning device and need to be performed by someone trained and accredited to take these particular views.
We have staff at all of our hospitals with PennHIP accreditation and can arrange for these to be performed if you have concerns about hip dysplasia in your dog, or want to assess their suitability for breeding.
What can be done about hip dysplasia?
There’s no ‘cure’ for hip dysplasia, but there’s a lot we can do to reduce pain, slow down arthritis, and keep your dog comfortable and active, and if needed, provide comfort surgically.
Non-surgical options (suitable for many dogs):
- Weight management – keeping your dog lean is one of the most powerful treatments
- Joint supplements
- Controlled exercise – staying active, but avoiding high-impact activities
- Pain relief and anti-inflammatory medications if needed
Surgical options
There are a number of surgical procedures that can be considered for hip dysplasia, depending on the age of the dog.
In the very early stages, if diagnosed before any remodelling of the bone has occurred, there are a number of procedures aimed at altering the shape of the joint to assist with how it load-bears, and therefore increase stability as they grow. The most effective of these is a juvenile pubic symphesiodesis (JPS) however this requires extremely early detection while they still have a lot of growth remaining, and as such we often recommend screening of dogs that show any subtle signs at an early age or are at particular risk of hip dysplasia based on their breed or known genetics.
In older dogs that already have arthritis or are too old to benefit from these bone-altering procedures, total hip replacement is the gold standard treatment to replace their arthritic joint with a smooth, artificial ball and socket. This restores normal joint function, range of motion, and provides pain-free movement of the hip joint.
When to get your dog assessed
Book an appointment with your regular vet for an assessment if you dog is showing any of these signs:
- Limping
- Slowing down
- Struggling to get up
- Avoiding stairs or jumping
- Or just not themselves
Early management can make a huge difference to long-term comfort and quality of life. If your regular vet has concerns about hip dysplasia in your dog, and would like to confirm the diagnosis through further imaging or surgery, they can refer you to one of our specialist hospitals to see our surgery team.
Dr Ryan Swepson
Specialist - Surgery
BVSc GradDipEd MVetClinStud MVetSurg DipECVS
If you have concerns for your pet in connection to this condition we recommend discussing it with your primary care vet in the first instance, or get in touch with our team for more information.
If you need urgent medical help, contact our 24 hour Pet Emergency team at Stafford, North Lakes, or Sunshine Coast on 1300 QLD VET (1300 753 838)