How hip dysplasia effects movement in dogs...

Hip dysplasia is one of those terms dog owners dread to hear but vets are diagnosing it more often nowdays. Technology which collects data from the dogs movement has allowed us to gather a better understanding of its impact on dogs and therefore can help in the diagnosis of this condition.

Hip dysplasia accounts for 30% of orthopaedic conditions diagnosed within dogs and is commonly associated with large breeds, genetically exposed puppies and fast growing dogs. Hip dysplasia is caused by a change in forces applied to the coxofemoral (hip) joint. More specifically the ball and socket joint which connects the fmeur (thigh bone) to the hip. This starts to reduce the strength of the bone as the cells within the bone are not able to produce more cells quick enough than the cells getting damaged. This is why hip dysplasia is commonly assosciated with osteoarthritis.

Clinical signs:

• Difficulty standing up or sitting down.

• Narrow based stance.

• Lameness.

• Reluctancy to move.

• Not lifting limbs high.

• Bunny hopping gait.

• Loading more weight onto the forelimbs.

• Pain and discomfort during range of motion tests.

Dogs are very good at compensating, however, these issues begin to spiral and without intervention will undoubtedly get worse.

Ground reaction forces (GRFs) have become an invaluable part of diagnosis. They provide us with information regarding the amount of force travelling up the dogs limb when the dog lands/stands on it. One study compared GRFs in the hindlimb of a healthy dog and dog with hip dysplasia of a healthy dog and a dog with hip dysplasia which found ther to be lower GRFs in dogs with hip dysplasia which indicated that the dogs will reduce their load on the hindlimbs. Further research regarding the movement of dogs with hip dysplasai found there to eb reduced stride frequency (the amount of strides the dog takes within a second) but longer stride length. This is said to be due to the joint having more laxity (movement) due to the alteration in forces previously discussed associated with hip dysplasia.

As well as aiding in diganosis it can also help determine the best course of treatment for dogs. Non-surgical treatment commonly opted for is non-steroidal anti-ifnlammtory drugs (NSAIDs) which help minimise pain and inflammation as well as weight control for dogs which can be deemed overweight or obese. Conservative treatment has shown to have promising results including that 6 out of the 7 owners with dogs diagnosed with hip dysplasia found that conservative treatment helped the dog to return to normal gait movement, improved joint range of motion and they were pleased with their dogs actviity level.

In more serious cases surgical intervention may be required with the most common survey being a total hip replacement. This specific surgery involves removing the top of part of the femur (femoral head) and replacing it with a metal ball whislt also resurfacing where the ball sits into the socket (acetabulum) with a cup implant allowing for a complete new joint. Dogs which underwent this type of surgery found that range of motion improved in 94% of cases within 5 years after surgery.