Elbow dysplasia in dogs

Overview

The elbow consists of three bones: the humerus, radius and ulna, whose joint surfaces must fit together.

A developmental disorder can distribute load unevenly across the joint, causing pain and lameness.

It is the most common cause of front-leg joint pain and lameness in large and giant dogs.

Changes have been found in both elbows in up to 80% of affected dogs.

Disease on both sides may be missed because the dog does not necessarily show obvious lameness in just one leg.

A damaged joint cannot be restored to complete health, but managing pain and function can provide a good long-term outcome.

More than one form of elbow dysplasia may occur in the same dog at once.

Causes

Developmental abnormalities of joint structures

Incongruence means that the opposing surfaces of the elbow joint do not fit together normally.

A difference in length between the radius and ulna can create a step in the joint surface, altering load distribution.

Cartilage wear and bone damage may develop in the overloaded inner part of the joint.

Medial coronoid process disease may involve a loose fragment, fissures, cartilage damage or abnormal bone shape.

In osteochondrosis, normal conversion of joint cartilage to bone is disrupted around the humeral condyle.

A flap or loose fragment of cartilage may form, causing inflammation within the joint.

In an ununited anconeal process, or UAP, a bony projection fails to join the ulna normally.

Fusion of the process should be complete by 5–6 months of age.

A process that remains mobile causes joint instability and predisposes the joint to osteoarthritis.

Instead of bony fusion, a fibrous connection remains between the ununited anconeal process and the ulna.

An abnormal shape of the ulna's joint notch may also contribute to incongruence of the joint surfaces.

Risk factors

Elbow dysplasia is influenced by several genes, rather than being inherited through a simple defect in one gene.

Genetics plays a major role, but environmental factors also affect how the disease develops.

The condition is more common in males than females.

Predisposed breeds include Labrador Retrievers, Golden Retrievers, Bernese Mountain Dogs and Rottweilers, which can develop medial coronoid process disease.

Ununited anconeal process is seen in German Shepherds, St Bernards and Basset Hounds.

Large size is not a requirement, because elbow dysplasia can affect a dog of any breed.

Offspring of apparently healthy parents can also develop elbow problems.

In short-legged breeds, premature closure of the ulna's growth plate can cause a distinct type of incongruence.

Elbow osteochondrosis is typically diagnosed in a rapidly growing dog at 5–10 months of age.

Different forms of elbow dysplasia are more common in different breeds, suggesting different inherited factors.

An inherited basis for ununited anconeal process is suspected but has not been confirmed.

Typical symptoms

Symptoms commonly begin at 4–7 months of age.

Mild disease may not become apparent until osteoarthritis develops at 7–8 years of age.

• Front-leg lameness worsens with exercise or is more obvious when starting to move after rest.

• Your dog takes shorter strides and moves the elbows through a smaller range than before.

• Your dog holds the elbow out to the side and may turn the paw inwards to take weight off the painful area.

• Enthusiasm for exercise decreases, and your dog does not want to continue a previously enjoyable walk.

• The joint looks swollen or feels warmer than usual.

• Your dog extends and bends the front leg because of pain.

Persistent pain can reduce muscle mass in the affected limb.

Cold or damp weather may make front-leg stiffness more noticeable.

A dog taking weight off a painful leg may lift their head as that foot touches the ground and lower it when stepping on the healthy leg.

Not every ununited anconeal process causes visible symptoms in a young dog.

Lameness does not usually disappear completely with rest alone, although it may improve at times.

Complications and consequences

A common consequence of untreated elbow dysplasia is progressive osteoarthritis, which can substantially affect a dog's everyday life.

About 60% of a dog's weight is carried on the front of the body, so painful elbows can severely restrict movement.

Osteoarthritis may progress despite surgery, even if lameness and pain improve.

On average, 85% of treated dogs show at least some improvement in lameness or discomfort.

This does not mean that the joint becomes healthy: treatment aims to preserve elbow function for as long as possible.

The long-term outlook depends on factors including the form of dysplasia and how much damage has already occurred.

When a joint already has obvious osteoarthritis, the additional benefit of surgery is less certain.

Diagnosis at the vet

Some dogs are not diagnosed until 4–6 years of age.

Investigating lameness

The vet assesses the dog walking and trotting, and checks for pain when bending and extending the elbow.

Both elbows are examined even if lameness at home seems to affect only one front leg.

X-rays may reveal osteoarthritis, loose fragments or an ununited anconeal process.

Computed tomography, or CT, helps identify even small coronoid process lesions.

Arthroscopy can be used both to identify and to treat damage inside the joint.

The severity of X-ray changes does not always match the amount of pain or the degree of visible lameness.

Elbow dysplasia is often diagnosed during a lameness investigation as early as 4–12 months of age.

A side-view X-ray with the elbow fully bent helps show an ununited anconeal process.

In osteochondrosis, imaging may reveal defects in the bone beneath the cartilage, loose fragments or flattening of the joint surface.

The vet may detect a grating sensation, called crepitus, when moving the joint.

Breeding screening schemes

Some breed-club screening schemes require a dog to be at least 12 months old.

The minimum age for particular breeds may be 18 or 24 months.

Some schemes require sedation for official X-rays.

In these schemes, the overall result is determined by the worse elbow.

Grade 0 indicates a normal elbow without detectable changes.

Grade 1 indicates mild changes; osteoarthritic changes may measure up to two millimetres.

Grade 2 indicates moderate changes: bony changes may measure up to five millimetres, or the joint may show findings suggesting dysplasia.

Grade 3 is assigned for severe changes or clearly demonstrable elbow dysplasia.

Some schemes accept CT at an approved centre either as the initial assessment or to clarify an X-ray result.

A CT assessment may change a previous official X-ray result in such a scheme.

Treatment

Choosing treatment

The vet plans treatment according to the type of lesion, the dog's age and the severity of clinical signs.

For a dog with mild symptoms, options may include weight management, adjusted exercise, physiotherapy and vet-prescribed pain relief.

Surgery may be needed when changes are substantial or other treatment does not relieve symptoms.

Arthroscopy can remove loose bone and cartilage fragments.

It also allows assessment of the extent of cartilage damage to help estimate the outlook.

However, removing a coronoid fragment does not correct all overloading of the inner part of the joint.

When necessary, a surgical cut in a bone can shift load away from the damaged part of the joint.

Depending on the situation, an ununited anconeal process may be fixed in place or removed surgically.

For a very severely damaged joint, joint replacement may be considered as a final surgical option.

However, elbow replacements can have serious complications.

Conservative treatment may also suit a severely damaged joint if conventional surgery is not expected to help.

Open surgery is an alternative when the chosen correction is not performed arthroscopically.

In osteochondrosis, after removal of a loose cartilage flap, the damaged area may be treated to encourage formation of repair cartilage.

In certain types of incongruence, a procedure on the ulna to guide growth may be considered for a dog under six months old.

Recovery and long-term osteoarthritis care

After surgery, calm, restricted activity usually continues for 2–6 weeks or longer, depending on the procedure.

Treatment of osteoarthritis associated with the medial coronoid process usually continues throughout the dog's life.

Weight loss can substantially reduce joint pain if the dog is overweight.

Rehabilitation may include massage and water-based exercise, even when surgery is not possible.

Suitable moderate exercise maintains joint function as part of pain management.

Supplements on the market do not all have the same effectiveness, so product selection forms part of the overall treatment plan.

Prevention

Feeding a growing puppy aims to maintain a lean body condition without restricting essential nutrients.

Repeated jumping down from a car or sofa, for example, can strain the front limbs.

Systematic examination of breeding dogs and openness about results help reduce the occurrence of elbow dysplasia.

Breeding from affected dogs is not recommended.

For certain short-legged breeds, some screening schemes issue an incongruence assessment instead of the usual elbow dysplasia assessment.

Appropriately moderated exercise during growth may reduce the development of clinical elbow disease.

Elbow results from other dogs in the litter also help with breeding choices, because examining the parents alone does not describe the full inherited risk.

Important for dog owners

When monitoring symptoms, consider willingness to exercise too, because disease in both elbows may appear as avoidance of walks.

Your dog may move more normally at times because lameness can be intermittent.

A support bandage or brace does not remove loose bone or cartilage fragments inside the joint.

Some official screening schemes require previous surgery for elbow dysplasia to be reported at the imaging appointment.

In such schemes, an operated joint is recorded as operated in the official assessment.

For breeding purposes, an operated result may be treated in the same way as the worst grade.

Before the appointment, record the age at which symptoms began and whether they are most apparent during walks or after rest. Agree rehabilitation, a target weight and pain monitoring with the treating vet.

A suitable warm-up may be about ten minutes of gentle walking before other planned exercise.

If a support or brace is tried, correct fit is essential for it to work.

Frequently asked questions

When does elbow dysplasia start causing symptoms in a puppy?

Symptoms often begin at 4–7 months of age. Lameness may initially be intermittent. Some mild cases do not become apparent until 7–8 years of age, when osteoarthritis starts causing symptoms. A puppy with symptoms needs clinical examination before reaching the age for official breeding screening.

Should both elbows be imaged if only one leg is lame?

Yes. Changes may affect both joints even if visible lameness mainly affects one leg. Disease has been bilateral in up to 80% of patients. Some official screening schemes also image both elbows at the same appointment. In these schemes, the overall result is determined by the worse joint.

Does a mild elbow grade mean the dog cannot be in pain?

No. X-ray grading and pain severity do not always match. A dog with grade 1 changes may be very painful, while a dog assessed as grade 3 may show little lameness. Treatment is therefore planned according to symptoms and the complete assessment.

Does removing a loose fragment completely cure the elbow?

No. Removing a coronoid fragment treats only part of the joint problem. Osteoarthritis that has already begun usually progresses despite treatment. Pain management, weight control and suitable rehabilitation can nevertheless provide a good long-term outcome. The resulting osteoarthritis often requires lifelong care.

Can elbow dysplasia be treated without surgery?

In mild or early cases, weight management, suitable exercise, pain relief and physiotherapy can relieve symptoms. Surgery is often needed if the disease has progressed or symptoms do not settle with other treatment. The vet assesses the options based on the examination findings.