Canine Hip Dysplasia (CHD) is a common orthopedic condition involving the malformation of a dog’s hip joint during its growth period. The hip is a ball-and-socket joint, but in CHD, the head of the femur (the ball) and the acetabulum (the socket) do not develop uniformly. This results in a loose fit, known as joint laxity, which prevents the joint from functioning properly. This instability causes abnormal wear and tear on the joint surfaces, ultimately leading to the painful secondary condition of osteoarthritis.
Understanding the Joint Structure and Dysfunction
A healthy canine hip functions smoothly because the femoral head sits deeply and securely within the cup-like acetabulum. In hip dysplasia, this relationship is disturbed, and joint laxity allows the femoral head to move excessively within the socket. This abnormal movement stretches the surrounding ligaments and joint capsule, which stabilize the joint. The body attempts to compensate for this instability by developing scar tissue and bone spurs.
The development of CHD is complex, stemming from a combination of genetic and environmental influences. It is a heritable, polygenic trait, meaning a dog’s risk is passed down through multiple genes. Environmental factors significantly affect whether the condition manifests and how severely it progresses.
Rapid growth and excessive weight gain during puppyhood place undue stress on the developing, unstable hip joint. Overfeeding large-breed puppies, allowing them to grow too quickly, substantially increases the likelihood of developing hip dysplasia. Maintaining a lean body condition and using diets specifically formulated for large-breed growth can help mitigate the expression of the inherited trait. This disparity between the rapid growth of bone and the slower development of stabilizing soft tissues is considered the underlying mechanical issue.
Recognizing Clinical Signs
The signs of hip dysplasia can vary widely depending on the severity of joint looseness and secondary arthritis. Owners may notice a reluctance to rise from a lying position or difficulty jumping up onto furniture or into a vehicle. This hesitancy often becomes more pronounced after periods of rest or vigorous exercise. Changes in gait are a common indicator, including noticeable lameness or limping in one or both hind legs. When running, some dogs adopt a distinct “bunny-hopping” gait, moving both hind legs simultaneously to minimize painful hip extension.
Over time, the dog may shift its weight predominantly to its front limbs, leading to visible loss of muscle mass (atrophy) in the rear quarters. Stiffness, reduced activity levels, and decreased enthusiasm for play or walks also signal discomfort.
Options for Management and Care
The approach to managing hip dysplasia is tailored to the dog’s age, size, lifestyle, and the condition’s severity. Many dogs can maintain a good quality of life through conservative, non-surgical methods aimed at controlling pain and inflammation. Maintaining a healthy body weight is the single most impactful non-surgical intervention, as reducing strain on the joint directly lessens discomfort.
Conservative care relies on modifying activity to include controlled, low-impact exercise, such as walking or swimming, which builds muscle support without jarring the joints. Other elements of conservative management include:
- Veterinary-prescribed medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), to manage pain and reduce inflammation.
- Joint supplements containing ingredients like glucosamine, chondroitin, and omega fatty acids to support cartilage health.
- Physical rehabilitation, including hydrotherapy and therapeutic exercise, for improving mobility and strengthening supporting muscles.
For dogs with severe pain that does not respond adequately to medical management, surgical interventions may be considered. Total Hip Replacement (THR) involves replacing the damaged joint with prosthetic components, offering the best potential for restoring normal function and eliminating pain. An alternative procedure, the Femoral Head Ostectomy (FHO), removes the femoral head entirely, allowing a “false joint” of scar tissue to form that alleviates pain caused by bone-on-bone contact. Other surgeries, such as the Triple Pelvic Osteotomy (TPO), are reserved for young dogs without existing arthritis, aiming to correct joint alignment before degenerative changes occur.