How do dogs hip joints work?

The dog’s hip joint is a ball and socket joint. The head of the femur (the femoral head) sits in the acetabulum. The acetabular bone fuses with the ilium, ischium and pubis of the pelvis to form the acetabulum.

The femoral head is nearly completely covered with articular cartilage which is thicker and has greater coverage than the cartilage within the acetabulum.

The hip joint has three axes of motion: flexion / extension, abduction / adduction and internal / external rotation. Adduction / abduction and rotation have a much smaller range than flexion / extension.

The hip joint is a very strong joint. During the three legged stance phase of the walking gait, the hip joint maximally bears the dog’s entire body weight. As speed increases or when the dog is jumping, load on the hip joint can be several times the dog’s body weight.

The role of the dog’s hind limbs is to provide propulsion. There are three muscles groups that articulate the hip joint to perform this function.

The first group are the hamstring muscles (femoral biceps, gluteals, semimembranous, adductor) which are responsible for hindlimb retraction (backward motion of the legs) and propulsion of the dog’s body forward

The second group of muscles include the femoral biceps, semitendinous, and gracilis. These muscles provide more propulsion or power as in when
walking uphill, moving at speed or jumping

The third group of muscles swing the hind leg forward. This muscle group includes the iliopsoas, tensor muscle of the fascia latae, sartorius and rectus femoris.

Ways to prevent hip joint problems in dogs

Diet

Over nutrition – Rapid growth in puppies

Over feeding and providing “extra” nutrients to growing puppies contributes to skeletal and joint problems. For more information please see https://www.fullstride.com.au/blog/should-i-feed-my-puppy-extra-calcium-and-protein

Weight management

Weight management is important for maintaining healthy hips. When the dog moves the hip joint bears the dog’s full weight during the stance phase of the gait. These forces increase with speed. To prevent overloading and wear injuries, maintaining a healthy body weight is critical.

For more information about the effect of obesity on dogs with osteoarthritis https://www.fullstride.com.au/blog/obesity-and-osteoarthritis-in-dogs

Appropriate exercise

Along with poor nutrition, over exercising puppies can negatively affect their skeletal development. For more information please see http://www.fullstride.com.au/blog/safe-exercise-for-puppies

After the skeletal growth phase, dogs need regular activity to to maintain soft tissue (muscle, tendon and ligaments) performance. Too little activity reduces the muscle’s ability to generate force. Regular physical activity produces additional myofibrils in the muscle fibres which increase the diameter of muscle fibres and the overall tone of the muscle. Activity also improves the muscles’ ability to use oxygen for energy supply and enhances the supply of nutrient rich blood to muscles by forming new capillaries in the muscles.

Additionally, exercise helps maintain healthy, well lubricated joints. Healthy, articular cartilage within the hip joint requires continuous strain. The cartilage within the hip joint is nourished by the diffusion of the joint fluid. When compressed, the joint fluid is pushed into the firm matrix of collagen fibres from which the solid matter in cartilage is comprised.

Conditioning for the dog’s activities

Very active dogs particularly those participating in dogs sports such as flyball, agility, dock diving, disc dogs, weight pull and the like put high demand on the muscles, tendons and ligaments that support the hip joint.

Without appropriate conditioning, the dog can easily strain the soft tissue surrounding the hip. The resulting muscle soreness and inflammation is likely to affect the dog’s gait and restrict hind leg movement.

Conditioning programmes for active dogs need to focus on building soft tissue strength and flexibility appropriate to the type of activity the dog performs. Additionally, balance and co-ordination skills needs to be considered to help prevent hip injuries. Finally, the dog’s cardiovascular fitness should be factored into a conditioning programme. Without the appropriate levels of endurance and stamina, the dog can easily strain muscles which in turn can affect hip joint function.

Lifestyle

The environment in which dogs live has a big impact on the health of their hips. Living on slippery floors increases the risk of slips and trips which can damage soft tissues and overload hip joints. Placing non-slip mats over slippery floors is a simple way to protect your dog from slips.

Dogs jumping up on furniture, beds or vehicles also places considerable strain on the hip joint. Consider adding ramps or stairs to ease the load on the dog’s musculoskeletal structure.

Finally, consider the dog’s bedding particularly for dogs with degenerative hip joint disease. Firm, raised beds will aid those dogs who are already experiencing difficulty getting out of a bed. It will also help maintain the health of younger dogs’ hip joints.

Muscle and joint maintenance

In addition to regular exercise and conditioning, regular maintenance of your dog’s hips and hind quarters can prevent serious muscle strain, inflammation and joint stiffness. Maintenance treatments reduce muscle tension and address inflammation. They will also maintain the flexibility in the hip joint and the full joint range of motion. Quarterly or bi-annual treatments can also serve as early detection of more serious joint problems.

As the hindquarters are the dog’s “engine” it is crucial that the hip joint and surrounding muscles are maintained and healthy. Leave me a comment here or on the Full Stride Facebook page on how you keep your dog’s hips healthy and supple.

Until next time, enjoy your dogs.

Sources:

Fischer, M.S & Lilje, K. E, 2014 Dogs in motion, 2nd edition, VDH Service GmbH, Dortmund, Germany

Hourdebaight, Jean-Pierre 2004, Canine Massage: A complete reference manual 2nd edition, Dogwise Publishing, Wenatchee WA, USA

Kainer, Robert A & McCracken, Thomas O 2003, Dog Anatomy: A Coloring Atlas, Telon New Media, Wyoming USA.