What is canine elbow dysplasia?
The word “dysplasia” means “abnormality of development”. The elbow is a complex joint because it involves the articulation of three bones; the humerus, radius and ulna. These fit together to allow normal movement. When these three bones do not develop correctly it results in abnormal forces acting on specific regions of the elbow joint. Elbow dysplasia is a syndrome that includes several conditions that result in incongruency (the joint doesn’t line up properly) and can lead to degenerative joint disease/osteoarthritis. These conditions include ununited anconeal process, and medial compartment disease most commonly, there are other conditions that make up elbow dysplasia but they are less common.
What is the cause of elbow dysplasia?
This condition is primarily of genetic cause, although environmental factors such as obesity during puppyhood may influence whether an animal with the genes coding for elbow dysplasia will develop a clinical problem.
The anconeal process of the ulna articulates with the humerus, which in a normal dog provides stability to the elbow joint. An ununited anconeal process can result from a disruption in the normal closure of growth plates in the elbow. This disruption leads to a lack of strong connection between two bones that is normally present in an adult dog. It can also result from damage to the distal ulnar growth plate, which results in the ulna becoming shorter than the radius and increasing force on the anconeal process, causing it to separate from the ulna.
Medial compartment disease refers to fragmentation of the medial portion of the coronoid process of the ulna, cartilage disease of the humeral trochlea and coronoid process, with or without incongruity of the joint. The coronoid process also develops from a separate centre of ossification, and failure of ossification results in fragmented medial coronoid process.
Elbow incongruity is commonly seen in the above described conditions. This is due to subtle differences in the growth rate of the two bones that make up the forearm (the radius and ulna) and can cause severe overloading of the prominent coronoid process and/or the anconeal process of the ulna. The consequence of this transient incongruity is stress fracturing of the coronoid process and ununited anconeal process.
What breeds are at risk for elbow dysplasia?
Ununited anconeal process is most common in large to giant breed dogs such as the Bernese Mountain Dog, German Shepherd, Golden Retriever, Labrador Retriever, Bull Mastiff, Newfoundland, Rottweiler and Saint Bernard Dog.
Medial compartment disease is most common in young large to giant breed dogs, including Labrador Retrievers, German Shepherds and Rottweilers, with males affected more commonly.
How can I tell if my dog has elbow dysplasia?
Elbow dysplasia is the most common cause of forelimb lameness in young large and giant breed dogs. There will often be a gradual onset of weight-bearing lameness in one or both forelimbs. This lameness may be triggered by exercise, with most affected dogs exercising normally but becoming lame afterwards.
Small dogs can also be affected by elbow dysplasia, and this problem should be suspected in any dog with fore limb lameness that has not been caused by trauma.
How is elbow dysplasia diagnosed?
During your consultation at North Coast Veterinary Specialist and Referral Centre one of our orthopaedic clinicians will perform a thorough clinical examination to isolate pain to the elbow and will discuss further investigation requirements and possible surgical intervention options should they be indicated.
Radiographs will usually show changes in affected dogs, although this is not always the case. Sometimes changes can be very subtle and difficult to detect and therefore the position in which the elbow is placed and the type of radiograph taken will have great bearing on the ability to perceive pathology.
In addition to radiography, we use CT imaging to facilitate the diagnosis of elbow dysplasia. CT must be performed under general anaesthesia. It is a very sensitive method for the diagnosis of stress fracturing of the coronoid process of the ulna and for the assessment of elbow incongruity. The images are submitted to a radiologist for interpretation once they have been taken and a report is provided outlining the changes noted in the elbows.
Arthroscopy is the gold standard technique for diagnosis of problems within a joint. It is a keyhole surgical technique that is performed under general anaesthesia for both diagnostic and treatment purposes. Arthroscopy allows us to obtain a magnified panoramic view of the inside of the elbow joint. In dogs requiring treatment of problems in both elbows, arthroscopy and surgery are performed as part of a single surgical procedure under the same general anaesthetic. When resolution of the problem can be arthroscopically achieved, your dog will generally be walking well the following day and recovery times are usually rapid.
How is elbow dysplasia treated?
Non-surgical treatments for elbow dysplasia
Non-surgical treatments are sometimes recommended for dogs that are affected by subtle pathology, and in dogs having no evidence of current elbow incongruity or radio-ulnar conflict. The cornerstones of non-surgical treatment are body weight management, physiotherapy, exercise modification, and medication (anti-inflammatory pain killers). These same techniques are also important in the short-term management of dogs who are treated surgically, although the primary surgical aim is to minimize the requirement for long-term exercise restriction and medication.
At North Coast Veterinary Specialist and Referral Centre, we have an in house physiotherapist that can provide your dog with a physiotherapy regime to aid in recovery much like in people. Physiotherapy will not cure any arthritic changes in the joint or on its own remove pain, but it can significantly help mobility and improve function for arthritic joints; and it can significantly improve outcomes achieved after surgery.
Surgical treatments for elbow dysplasia:
- Surgical reattachment of fragments: Surgical reattachment of the anconeal process or fragmented medial humeral epicondyle can be performed in dogs younger than 6 months and if the fragments are large enough to facilitate placement of an implant, but suitability would be decided upon on a case-by-case basis.
- Arthroscopic fragment removal: This is commonly performed in cases of ununited anconeal process. The majority of dogs will make a rapid clinical improvement after arthroscopic fragment removal, and in some cases this improvement will be maintained in the long term.
- Subtotal coronoid ostectomy (SCO): Performed in cases of fragmented medial coronoid process, where the fragment is removed arthroscopically. The majority of dogs will make a good clinical improvement after SCO and in many cases this improvement is maintained in the longer term. Osteoarthritis is progressive for all forms of medial coronoid disease regardless of whether fragment removal alone or SCO is performed.
- Ulnar ostectomy: In elbow joints that have documented incongruency as the underlying cause of ununited anconeal process, distal ulnar ostectomy may be performed additionally to realign the joint. The triceps muscles act to pull the ulna proximally during weight bearing into an anatomically normal position. Cutting the bone does not prevent the animal from using the limb to weight-bear and walk, and healing of the ulna occurs in a new position to provide a more congruent elbow joint.
- Bicipital Ulnar Release Procedure (BURP): This procedure is also used in some cases of rotational incongruity of the elbow joint that results from forces of the biceps muscles on the elbow by cutting the biceps tendon at its distal (toward the elbow) attachment.
- Elbow arthrodesis: Elbow arthrodesis (fusion of the elbow joint) is considered a salvage procedure that alleviates pain due to arthritis but results in significant loss of function.
- Elbow replacement: Elbow replacement is considered a salvage procedure. Although it is often preferred compared to elbow arthrodesis, it has a much longer recovery and increased risk of complications.
Elbow dysplasia is a complex disease process with many different surgical options for treatment or management of this condition. Each case may present differently, and the optimal treatment option for your pet will be decided upon on a case-by-case basis and discussed with you after diagnosis.
What is the long-term consequence of elbow dysplasia?
Every dog with elbow dysplasia is affected by some degree of elbow osteoarthritis at the time of diagnosis. Surgical treatments for elbow dysplasia aim to treat the current source of pain and minimize the progression of osteoarthritis. Non-surgical treatments for elbow dysplasia aim to treat elbow pain and maintain mobility, but do not have the potential to minimize osteoarthritis progression.
Rehabilitation of elbow dysplasia can be provided through our rehabilitation service whereby one of our physiotherapists will design a home care physiotherapy and exercise plan for you to follow at home between outpatient physiotherapy and hydrotherapy appointments.
The clinical impact of elbow osteoarthritis is unpredictable and regardless of treatment, arthritis will progress to some extent for all affected joints. In some dogs, lameness can be mild and intermittent, whilst in others lameness can cause severe and permanent disability.
The long-term prognosis is dependent on the degree of osteoarthritis in the remainder of the elbow joint and this is discussed by your orthopaedic clinician on an individual basis.
