Abnormal Development of the Elbow in Dogs

Three bones, the radius, the ulna and the humerus, combine to form the elbow joint on a dog’s foreleg. Abnormal growth patterns among any of the bones can lead to pain and eventually joint degeneration and arthritis. This is called elbow dysplasia. In dogs, there are a number of different conditions that cause elbow dysplasia. Mismatched growth can lead to improper closure of growth plates and fragmented bone spurs, or improper cartilage development may increase joint wear and tear. The different types of elbow dysplasia all have similar symptoms of pain, inflammation, and lameness. The problem may develop in only one leg, or it may be bilateral. Most cases can be treated with surgery, but many dogs may not completely regain normal function. Dogs that are not diagnosed in the early stages of the disease often have higher levels of joint degeneration and are less treatable. The problem is more common in large and mid-sized breeds of dogs, but veterinarians don’t know exactly what causes it. There may be some dietary factors, especially a diet high in calcium and vitamin D supplements. Elbow dysplasia is usually diagnosed in the first year of a dog’s life, but in some cases, dogs don’t show symptoms until middle age.

If the bones of a dog’s foreleg develop abnormally, this can limit mobility and cause pain and inflammation. Veterinarians call this elbow dysplasia. Untreated, it will lead to joint degeneration and early onset arthritis.

Take your dog to see a veterinarian if you notice any of the following symptoms.

• Inability to extend elbow joint
• Pain
• Lameness in one or both front limbs
• Asymmetrical gait
• Joint inflammation
• Stiffness especially after lying down
• Unwillingness to exercise
• Joint degeneration and progressive arthritis in the front legs

Types

There are four different types of elbow dysplasia which may occur separately or together.

• Fragmented medial coronoid process (FMCP) – the radius develops shorter than the ulna putting pressure on the medial coronoid and causing fragmentation
• Osteochondritis dissecans (OCD or OD) – the cartilage flap is partially or completely separated from the joint
• Ununited anconeal process (UAP) – failure of the growth plate between the ulna and the anconeal process to close
• Incongruity of the elbow joint (INC) – the bones grow asymmetrically and do not fit together well

Elbow dysplasia is more prevalent in some breeds, but it can develop in any dog. Veterinarians believe some lifestyle factors may contribute to the problem.

• More common in medium to large breeds
• FMCP – Labradors, Bernese Mountain Dogs, Rottweilers, German Shepherds
• OD – Retrievers, Newfoundlanders
• UAP – German Shepherds, Bloodhounds, Bassets, St. Bernards, Great Danes
• INC – Bernese Mountain Dogs, Chondrodystrophic breeds (dogs with shortened limbs)
• Diet too high in calcium or vitamin D
• Excess weight

The veterinarian will examine your dog’s symptoms of inflammation and test the range of motion in the joint. Lameness and abnormal gaits can be demonstrated on an office visit, or via a cell phone recording. The vet will ask about your dog’s breed and family history, especially for dogs in their first year of life when elbow dysplasia usually becomes apparent.

X-rays will be taken of the joint. These will show the degree of joint degeneration and sometimes the type of elbow dysplasia as well. UAP is often visible on an X-ray, but the bone fragments and displaced cartilage that are present with FMCP and OD may be more difficult to detect. A CT scan and/or an MRI may be ordered to diagnose these conditions.

Surgery is the most common treatment for elbow dysplasia. FMCP and OD can usually be treated with minimally invasive arthroscopic surgery. For this surgery, only a small incision is necessary, and an instrument will be inserted to extract the bone fragment or the piece of loose cartilage. UAP usually requires more invasive surgery. In some cases, the entire anconeal process can is removed; in others screws will be inserted to reattach the growth plate. Various types of reconstructive surgery may be necessary to realign the bones for INC. In many cases, the veterinarian will refer your dog to a specialist surgeon.

Depending on the extent of the surgery, your dog may need to be confined for 2-6 weeks. Arthroscopic surgery has a quick recovery time, but other types of surgery and joint reconstruction will take longer. In some instances, the veterinarian may not recommend surgery if symptoms are very mild, or if joint degeneration is very severe and there is a low chance of successfully reconstructing the elbow. Daily NSAIDs may be prescribed to reduce pain and inflammation and the dog will need to maintain a low weight and limit exercise.

About 60% of dogs with UAP return to normal function after surgery. About 75 % of dogs with OD and FMCP will have improved elbow function, but any recovery will depend on the amount of degeneration that is present in the joint. Most dogs will have some improvement, but may still have reduced mobility and will probably develop arthritis in the joint at a younger than normal age. It’s very important to maintain a low weight and limit activities that could put stress on the joint. Hydrotherapy can be a beneficial form of non-weight bearing exercise. Dietary supplements of Omega 3 and glucosamine can help reduce arthritis. Prescription diets are also available for this purpose.

Dogs that are at risk breed-wise could benefit from being kept on a diet lower in calcium and vitamin D in order to prevent a problem from developing. Some studies have shown that large amounts of these nutrients added to dog food can contribute to the problem. Regular check-ups and monitoring can also help to catch elbow dysplasia before it becomes untreatable.