Osteochondritis Dessicans (OCD) of the elbow refers to poor mineralisation of the bone under the articular cartilage at the bottom of the upper arm (humerus). This abnormality in the bone under the cartilage allows a flap of cartilage to form within the joint. This flap of cartilage can be large and cause significant lameness and pain in the elbow joint when it becomes detached.

The condition is commonly diagnosed in young, rapidly growing, large breed dogs, with patients being diagnosed at 1-2 years of age. The large mobile fragment and abnormal wear of cartilage within the joint lead to the progression of debilitating osteoarthritis and ongoing joint pain. The diagnosis of elbow OCD is based on clinical examination and evidence of a bone defect on the humerus seen on x-rays.

Treatment usually involves arthroscopic removal of the cartilage fragment and clearing of the underlying bone, to allow the formation of scar-cartilage in its place. Other options include Kyon PAUL with 80% having an excellent outcome.

The prognosis for resolution of the lameness and return to function is reasonable, despite the progression of osteoarthritis, but considerably better than those patients who are left untreated.

Complications following arthroscopy are very low, with an expected quick post-operative recovery, and improvement of function in the weeks following the procedure. The joint will have some swelling following the surgery, but this should resolve without issue in 2-5 days. Infection is the most common complication (usually less than 2%) which should be monitored for following surgery, and is generally easily treated with antibiotics and in serious infections, washing of the joint with sterile salin

One of the most common causes of fore limb lameness in the dog is Elbow Dysplasia. Elbow Dysplasia is a generic term meaning arthritis in the elbow joint. As in people, arthritis in the dog is painful, resulting in intermittent and persistent lameness, especially following physical activity.

Elbow Dysplasia has 4 developmental causes:

1. Osteochondritis Dessicans (OCD)
2. Ununited Anconeal Process (UAP)
3. Fragmented Coronoid Process (FCP)
4. Elbow In-congruency

Elbow Dysplasia that develops as a result of one or a combination of OCD, FCP, and Elbow incongruency is referred to as Medial Compartment Syndrome. Put simply, elbow dysplasia is early onset arthritis resulting from the abnormal development of the elbow joint. It is believed to be due to a combination of genetic factors, diet, rapid growth, and/or trauma.

Signs of Medial Compartment Disease:

• Sudden and/or gradual lameness on one or both fore limbs
• Stiffness and/or decreased range of motion after long periods of rest
• Fore limb lameness following exercise
• Initial signs may appear between 5-12 months of age

Consequences of Elbow Dysplasia

• Cartilage deterioration releases a combination of inflammatory factors from the ligament.
• Increasing instability of the joint from the damaged cartilage causes arthritis to develop quickly within the joint.
• Every time the pet bears weight on the affected leg, abnormal or overloading of the medial compartment occurs. This abnormal loading often leads to concurrent cartilage erosions (often full thickness) and possible fragmentation of the medial coronoid. Once the cartilage is damaged arthritic change accelerates and perceived pain worsens.
• A vicious cycle of compensation related damage leads, in many instances, to debilitating lameness.

Treatment Options:

Elbow dysplasia and medial compartment disease is a condition in need of a better treatment. At the moment relatively few options are available for these patients. Treatment options to minimize lameness range from conservative treatment, prescribing pain management drugs and special diets, to aggressive surgical treatment, cutting bone to alter joint biomechanics and even total elbow replacement. Although pain management drugs may help the dog feel better and cope with a bad elbow, they do not alter the progression of disease.

The PAUL is a novel new paliative technique for the treatment of this lameness, showing particular benefit in younger patients, treated prior to the advanced stages of osteoarthritis.

BIOMECHANICAL RATIONALE:

The PAUL technique was developed on the basis of several observations and biomechanical analysis of the canine elbow joint:

• A consequence of medial compartment disease, a subset of elbow dysplasia, is medial collapse of the contact mechanics of the elbow joint;
• Medial collapse overloads the medial compartment, exacerbating existing lameness and joint pain;
• A slight abduction, by 4 – 6 degrees, of the ulna results in an unloading of the medial compartment, alleviating pain;

EXECUTION:

The PAUL involves an osteotomy of the proximal portion of the ulna. A specially designed ALPS PAUL plate is fixed to impose a corrective limb alignment, aimed at unloading the medial compartment. This new alignment unloads the medial compartment, alleviating lameness, stiffness, and joint pain.

Long-term options for the management of elbow dysplasia are based on maintenance of lean body condition, physiotherapy, joint supplementation (fish oils, glucosamine, chondroitin, pentosan polysulphate injection), joint anti-inflammatories and exercise moderation.