Elbow dysplasia is a term used to describe generalized osteoarthritis of the elbow joint caused by non-traumatic developmental abnormalities. Four common manifestations of elbow dysplasia include: fragmented medial coronoid process (FMCP), osteochondritis dissecans (OCD) of the medial aspect of the humeral condyle, ununited anconeal process (UAP), and articular cartilage anomaly or incongruence between the humerus, radius , and ulna. See illustration. The International Elbow Working Group in 1993 agreed that elbow arthrosis caused by one of these four conditions is the manifestation of inherited canine elbow dysplasia. Elbow dysplasia is a common inherited condition seen in Labrador Retrievers and Bernese Mountain Dogs, but can be seen in most breeds. This disease is bilateral (both elbows) in approximately 35% of affected dogs.
What are the clinical signs seen with this condition?
Affected dogs are often lame or have an abnormal gait. The onset of lameness is usually between 4-6 months of age however, clinical signs may not be obvious until much older (1-2 years of age). In some cases, we see late onset FMCP perhaps secondary to chronic increased stress in the medial compartment of the joint and/or traumatic insult to an otherwise abnormal joint. Delayed presentation of lameness may also manifest in middle-aged or older patients as arthritis progresses.
How do we diagnose these problems?
The diagnosis of elbow dysplasia is primarily based on clinical signs and radiographic evaluation of the elbow joint. Specific developmental abnormalities such as UAP and OCD of the elbow joint are often fairly apparent on standard x-ray projections. The diagnosis of FMCP however, can be somewhat more elusive. Orthopedic examination findings (pain over the inner aspect of the elbow joint), x-ray changes in the elbow joint, and exclusion of other orthopedic conditions are tools that aid in the diagnosis. Standard x-rays often do not confirm the presence of FMCP, but rather provide information about the general congruency of the elbow joint and highlight changes around the joint that support the diagnosis of FMCP. It is recommended that x-rays be performed on both elbows due to the high incidence of bilateral disease.Confirmation of FMCP is made either with a CT scan or with arthroscopy/surgery.
What are the treatment options?
Each patient is unique based on the age of diagnosis, the severity of the osteoarthritis, and the specific problem(s) affecting the elbow joint. There is some degree of variability amongst surgeons as to the preferred surgical approach based on the nature of the problem. Most agree that the joint should be surgically explored (mini surgical approach or arthroscopy) preferably before severe osteoarthritis develops. In the case of FMCP, debridement (removal) of the loose fragment(s) and /or performing a sub-total coronoidectomy is the cornerstone of surgical treatment. This may be combined with a surgical release of the lower attachment of the biceps tendon; biceps ulnar release procedure (BURP). Early anecdotal evidence suggests this technique may relieve ongoing pressure over the inner (medial) aspect of the elbow.
Newer surgical treatments are being developed to address end-stage osteoarthritis of elbow joints. These patients have substantial cartilage loss that is irreversible. Sliding humeral osteotomy (SHO) and ulnar osteotomies (bone cuts) can transfer forces to the lateral or outer part of the elbow joint thereby alleviating stress on the medial or inner compartment. Complete and partial elbow replacements, stem cell therapy and platelet rich plasma (PRP) injections are also being researched and developed.
Expectations with Surgery
The success of surgery largely depends upon the extent of arthritis and cartilage damage that is already present as well as the degree of incongruency (improper fit) of the elbow joint. Most dogs, if operated early enough, are significantly improved in their lameness within the first 8-10 weeks after surgery. However, some dogs don’t show considerable improvement for 3-4 months after surgery. There is also a subset of dogs that continue to show lameness despite the successful removal of loose fragments. For these patients, consideration is given to the above mentioned load-transfer surgeries. The sooner surgery is performed to address elbow dysplasia the more likely dogs are to improve in their mobility and pain.
Osteoarthritis, with or without surgery, often progresses in the affected elbow joint(s). The aim of surgery is to remove the source of pain and slow the advancement of arthritis.
Physical therapy/rehabilitation/hydrotherapy, acupuncture, cold laser therapy, Adequan injections and traditional anti-inflammatory and pain relief medications are often considered for patients that continue to display lameness.