What is canine hip dysplasia?
Hip dysplasia is an abnormality in the hip joint that affects the ‘ball and socket’ nature of the joint and makes the hip more lax.
It’s a common condition, particularly in larger dogs, but can also affect small dog breeds and cats. The condition is mostly genetic, although external factors like obesity in puppyhood may have an effect on its development in later years.
What are the symptoms?
Hip dysplasia in dogs tends to be noticeable in symptoms relating to their hind legs. These can include:
- Hind limb stiffness
- Trouble exercising
- Difficulty rising
- Swaying when walking
- Limping on hind legs
These symptoms usually develop when the dog is young and growing (the first year of their life) or during early adulthood. Hip dysplasia will often lead to arthritis.
Hip dysplasia signs vary with the age of the animal. Those in the younger group often present with a sudden onset of unilateral disease. Owners often report a sudden reduction in activity associated with marked discomfort of the hindlimbs. Difficulty rising is often reported along with a decreased willingness to walk, run and climb stairs. At this age the femoral heads often appear normal on x-rays.
Most affected dogs between 12-14 months of age walk and run freely and are free of significant pain. Most exhibit a “bunny hopping” gait when running. Those dogs that present in the older group have different signs as they suffer from chronic degenerative joint disease and its associated pain.
Lameness may be unilateral but is more commonly bilateral and most commonly signs become apparent over a long period of time. Owners report lameness after prolonged or heavy exercise, a waddling gait and severe difficulty rising. The range of motion of the affected joints is restricted.
Examination – The first step of diagnosis may be a clinical examination. Your vet might have noticed an unusual gait, and wish to examine your pet further.
Advanced imaging – Our specialists might suggest your pet undergoes an MRI or CT scan, where they’ll be looked after by our caring nursing team.
Consultation – You’ll then have a consultation with one of our orthopaedic clinicians, who will be able to effective diagnose hip dysplasia and offer a proposed treatment route.
How do we treat hip dysplasia?
There are a range of treatment options that will depend on the severity of the condition. Many dogs with hip dysplasia show no signs of pain while others only have mild intermittent signs. Approximately 75% of dogs in which hip dysplasia is diagnosed at an early age have minimal gait abnormalities 4-5 years later. A large number of these animals can be treated with conservative methods including minimising activity and the use of anti-inflammatory agents when required. Your specialist will be able to advise on the best course of action for your pet.
A large variety of surgical techniques have been introduced in an attempt to treat the clinical signs of hip dysplasia and arthrosis. The four most commonly employed are Juvenile Pubic Symphysiodesis (JPS), Triple Pelvic Osteotomy and Double Pelvic Osteotomy (TPO and DPO), Femoral Head and Neck Excision and Total Hip Replacement (THR). The operation most suitable for your dog will be discussed in detail in your consultation.
Juvenile Pubic Symphysiodesis
This is a procedure that may be performed in dogs with hip dysplasia if it is recognised at a very early age. It is a relatively minor procedure that may result in a more stable hip in the very young animal. For maximum effect the surgery should be performed at approximately 3-5 months of age while significant growth potential remains.
A small incision is made between the hindlimbs to expose the pubic bone of the pelvis and the area from which growth of this bone occurs, the growth plate, is cauterised to destroy all the growing cells. When growth from this centre stops and the remaining portions of the pelvis continue to grow, the sockets of the hips rotate over the femoral head. It is likely that your dog will be allowed home on the same day.
It is very unusual for hip dysplasia to be diagnosed sufficiently early for this procedure to be of benefit but in the unlikely case that this surgery is applicable for your pet, this will be discussed in more detail in your consultation.
Triple pelvic osteotomy and double pelvic osteotomy (TPO/ DPO)
TPO/DPO is an effective method of treating dysplasia if carried out early. This operation is most commonly carried out between 4 and 7 months of age. The most important criterion determining success of TPO is not age but the condition of the joint surfaces. If the acetabulum is filled with bone or fibrous tissue or the socket has been worn away or the cartilage on the head of the femur is damaged then TPO will fail. This analysis is made on standard radiography and using a test, performed under anaesthesia, to assess the condition of the socket via the sensations felt when the hip joint is manually dislocated and popped back into place.
The operation involves two or three cuts being made in the pelvis allowing the socket to be rotated to provide adequate stabilisation for the head of the femur. A plate is then used to maintain the new positioning of the bones. Recovery involves 6 weeks of restricted exercise with lead only walking. In many cases this operation will be required bilaterally, and the second operation will normally be carried out 4-6 weeks following the first. Cases must be selected carefully as many patients will not benefit from this surgery.
One further factor to consider is that total hip replacement is significantly more difficult to perform in an animal which has already undergone TPO.
Femoral head and neck excision
This operation is only normally considered in cases where THR is not a financially viable option. This is a non- reversible procedure and must be considered a salvage option. However, it is a valuable method for improving the quality of life of patients with hip dysplasia by elimination of pain.
In this technique, the femoral head and neck are completely removed allowing a false joint to form. Pain is relieved by elimination of bony contact between the femur and the pelvis as scar tissue interposes. Some abnormality of gait persists due to limb shortening and a slightly reduced range of motion but the animal is pain free. This procedure can be performed bilaterally if required. Recovery involves early active use of the limb. Exercises are performed known as “passive range of motion exercises” which are started immediately following the operation and lead walking is encouraged for two weeks. After stitches have been removed, swimming is encouraged. This operation is much more successful in animals which have maintained an appropriate body weight with smaller animals experiencing significantly less severe gait abnormality following surgery, however, pain relief is readily accomplished with this technique even in larger patients.
As for TPO, THR becomes much more complicated following femoral head and neck excision.
Total Hip Replacement
Not every dog with hip dysplasia is a candidate for THR. Other causes of lameness must be ruled out before THR is considered, including knee problems and spinal disorders, and in some patients there is insufficient bone present to allow placement of the implants.
Detailed planning is required before the operation allowing measurement of required implants and assessment of the joint. For some animals, femoral head and neck excision may be the only option. As both options offer pain relief the major advantage of THR over femoral head and neck excision is that normal biomechanical function is maintained.
In this technique a new socket of polyethylene, and a new femoral head and neck of stainless steel are implanted. Recently, new, smaller implants have become available making this procedure viable in any size of dog. Two different systems are available termed biologic (non-cemented) and cemented systems, and which is used depends on various factors related to each individual patient. Recovery involves six weeks of cage rest with twelve weeks lead only walking.
Most dogs return to full function by eight weeks postoperatively and the operation carries a 95% success rate. Catastrophic complications can occur however with infection, fractures and loosening of the implants being the most significant causes. Failure may be perceived in the weeks following surgery or can become apparent years later. You can view further information about total hip replacement here.