• Most common cause of elbow lameness in young rapidly growing dogs of large and giant breeds.
• Was initially thought to be a form of osteochondrosis but much work more recently has refuted this.
• Can co-exist with ununited anconeal process (UAP Ununited anconeal process ) or osteochondrosis dissecans of the humeral condyle (OCD Elbow: osteochondritis dissecans ) - likely inherited predisposition.
• Cause: currently controversial and incompletely understood. Some dogs appear to have axial incongruency of the radius and ulna and a short radius has been associated with changes to the medial coronoid process on CT and arthroscopy. In addition some dogs appear to have an arc of curvature of the ulnar trochlear that differs to that of the trochlear of the humerus - this may overload both the medial coronoid process and anconeal process causing MCPD and UAP concurrently. However, some dogs do not have incongruency at the time of presentation so the precise contribution of incongruency in the pathogenesis of MCPD is uncertain.
• Signs: progressive, uni- or bilateral forelimb lameness from 4-5 months of age, abnormal gait ('duck-footed'), pain on full elbow extension and/or full flexion of the elbow with concurrent supination of the antebrachium, effusion, thickened joint(s).
• Treatment: remains controversial. Options include: conservative/medical management; excision of fragmented coronoid arthroscopically or by conventional surgery; proximal ulna osteotomy to redistribute load on site, if medial compartment disease is present proximal abducting ulnar osteotomy (PAUL) or sliding humeral osteotomy (SHO) can be considered. If end stage joint disease is present elbow replacement may be indicated. There are a lack of prospective, objective studies comparing outcomes of these treatments making precise recommendations in each case challenging.
• Prognosis: difficult to predict - many cases remain lame and almost all continue to develop degenerative joint disease (DJD Arthritis: osteoarthritis ).

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Presenting signs

• Progressive, uni- or bilateral forelimb lameness from 4-5 months of age Lameness: forelimb - investigation.
• Abnormal gait/limb carriage - outward rotation of feet, elbows held close to body ('duck-footed').
• Pain, especially on external rotation and hyperextension of joint.

• Lameness worse after rest or heavy exercise.
• Secondary DJD.
• Reduced range of joint movement - range of motion often in early cases but may often loose flexion with progression of osteoarthritis Arthritis: osteoarthritis.

• Crepitus.
• Thickening of joint capsule, especially lateral side caudal to humeral epicondyle.

• Joint effusion.

Age predisposition

• Young animals - more than 4-5 months old with most dogs presenting with signs at less than 12 months of age. However, there is a subset of older dogs presenting with forelimb lameness that have medial coronoid process changes.

Breed/Species predisposition

• Any large breed rapidly growing dog.
• Rottweiler Rottweiler.
• Labrador Retriever Retriever: Labrador.
• Bernese Mountain Dog Bernese Mountain Dog.

• German Shepherd Dog German Shepherd Dog.
• Golden Retriever Retriever: Golden.
• Saint Bernard St Bernard.
• Chow Chow Chow Chow.
• Rhodesian Ridgeback Rhodesian Ridgeback.
• Newfoundland Newfoundland.

Cost considerations

• Surgery may be indicated.