Canine Hip Dysplasia (CHD) is a multifactorial disease that has received massive amounts of funding.
The clinical signs of hip dysplasia generally become evident to owners between 5-9 months of age. Since laxity can be measured at 4 months of age this suggests that laxity is not the sole cause of clinical signs. This gives credence to the thought that the consequences of laxity, namely, damage to the joint margins and synovitis result in the clinical signs.
Palpation tests – Ortolani Sign: This is the most widely used palpation test. This can be performed in the anaesthetised or heavily sedated patient in lateral or dorsal recumbency. The test relies on manual force to subluxate the femoral head, gradual abduction of the hip joint allows relocation of the femoral head in to the acetabulum. This relocation is palpated as a “clunk.” The clinician is required to evaluate this clunk to give some idea as to the depth of the acetabulum. There is little correlation demonstrated between Ortolani signs and radiographic signs (Puerta).
Traditional radiographs give little information on laxity but does allow for evaluation of the secondary changes within the joint. Extension of the hip can cause tension in the joint capsule and resultant medial displacement of the femoral head within the acetabulum creating a false impression of the joints congruence.
Tests for Laxity:
Penn Hip -This is a technique to assess laxity on a neutral hip position, provides a numerical value to the degree of laxity termed the distraction index (DI). There is an alternative technique the dorsolateral subluxation technique (DLS) which is similarly designed to assess the degree of laxity. Evaluation of DI has highlighted breed differences in tolerance for passive laxity. In various studies DI was the strongest predictor for development of osteoarthritis. Across all breeds a DI of less than 0.3 indicates a low likelihood for development of osteoarthritis.
The options for treatment of CHD depend on a number of variables such as severity of clinical signs, age, breed, weight and also the feelings of the owner. There is a study (Barr) that suggests that 75% of animals that are born with hip dysplasia will have good clinical function without the requirement for surgery. Conservative therapy is relatively uniform across the board for orthopaedic disease and consists of controlled activity such as leash walking, dietary management to provide an optimum body weight, physical therapy and judicious use of non steroidal anti-inflammatory medications when necessary. Joint supplements such as glucosamine and chondroitin are also being commonly used at this point in time based on their use in the human field.
Non-surgical management may allow some improvements in lameness or pain in the short term, particularly in patients with only very limited disease development, with approximately 60-80% of younger dogs showing good improvements. Four basic methods are usually recommended:
- Body weight management
- Exercise modification, physiotherapy and hydrotherapy
- Anti-inflammatory / pain relief medications
- Nutraceutical supplements
In many patients with hip dysplasia, even those as young as 7-10 months old, the cartilage damage and osteoarthritis is so severe that medical management cannot achieve a good enough quality of life and further intervention is indicated.
Juvenile Pubic Symphsiodesis (JPS)
JPS is a relatively recent development largely pioneered at the University of Wisconsin-Madison. Clinical and research trials have shown that this technique needs to be performed between 15 and 20 weeks of age to have appropriate clinical response. This technique requires fusion of the pubic symphysis which results in rotation of the acetabulum to provide greater coverage of the femoral head. This fusion is achieved via ventral approach to the pubis and treatment with either metallic staples or most commonly electrocautery. All patients undergoing this technique should be neutered as the radiographic phenotype of these dysplastic patients will be altered. This surgery is hampered by the requirement to see these patients prior to 20 weeks of age and so is at present rarely performed in our practice.
Total Hip Replacement (THR)
THR has revolutionised the treatment of debilitating osteoarthritis of the hip joint.
When is a Total Hip Replacement required?
When relevant orthopaedic conditions progress to the point where they’re causing an animal significant pain, despite drug and exercise management, our orthopaedic specialists may suggest a total hip replacement.
Total hip replacement has revolutionised the treatment of debilitating osteoarthritis of the hip joint. It can also be used in the management of recurrent luxations and fractures of the hip joint that can’t be reconstructed.
How to Tell If Your Pet Needs a Hip Replacement?
If your pet is running with a swing or bunny hop, it’s likely that they’re suffering from an orthopaedic condition that could result in the need for a hip replacement. Once seen by a specialist, such as Hamilton Specialist Referrals, you will be able to establish if your pet is a good candidate for this surgery.
To undergo total hip replacement surgery, your pet needs to be in good overall health with no other bone or nerve disease. They will also need to be fully grown (unless the condition is too severe to wait) to ensure they don’t outgrow the hip replacement. This typically occurs between 9 and 12 months of age, depending on the breed.
What does Hip Replacement Surgery Entail?
The hip joint is made up of a ball and socket joint, with the ball joint at the top of the thigh bone and the socket in the pelvis. This surgery removes both the ball and the socket joint, replacing them with prosthetics. Hamilton Specialist Referrals exclusively use joint replacement implants manufactured by BiomedtrixTM, who are considered the world leader in veterinary joint replacement technology.
Primarily, they use non-cemented components in larger dogs but have the ability to perform this procedure on even the smallest dog breeds, as well as cats.
Rehabilitation and Recovery from Total Hip Replacement Surgery
After the surgery is complete, your pet will likely have to stay in the hospital for between 3 to 5 days, ensuring the beginning of the healing process runs smoothly. Once your pet has been released from the hospital, the stiches from the incision will still be in for a further 10 to 14 days, so it’s important to ensure these are left alone to heal.
Once the initial healing process is complete, comprehensive/physical pain management with our rehabilitation team will be an essential part of your pets successful recovery.