Ununited Anconeal Process in Dogs: Causes, Signs & Treatment

Ununited Anconeal Process (UAP) is a developmental condition where the anconeal process, a part of the ulna bone, does not fuse with the ulna as it should. This affects the elbow joint stability, especially when dogs extend their front legs, causing pain and lameness. UAP mostly appears in young dogs aged between five and nine months and affects large breeds more frequently, such as German Shepherd, Saint Bernard, and Basset Hound.

The Cause of Ununited Anconeal Process

The anconeal process normally fuses with the ulna by 16-20 weeks of age. Failure of this fusion results in UAP, often due to genetic factors and elbow incongruity where bones do not align correctly. Dogs affected may also suffer from related elbow abnormalities such as osteochondritis dissecans, involving loose bone or cartilage fragments in the joint, causing increased pain and discomfort.

Breeds Most Prone to UAP

Certain breeds are genetically predisposed to UAP, particularly large breeds with specific elbow conformations. German Shepherds, Saint Bernards, and Basset Hounds feature prominently. Reputable breeders avoid using affected dogs for breeding due to the hereditary nature of this condition. Prospective owners should always seek information on health clearances from breeders before finding a puppy.

Recognising the Signs of UAP

UAP can affect one or both elbows. Common signs include:

• Forelimb lameness, often persistent or intermittent
• Swollen elbows
• Elbow pain, especially noticeable when extending the front leg

Dogs usually show symptoms between four and twelve months of age. Left untreated, symptoms worsen and arthritis may develop, leading to chronic pain and decreased mobility.

How Vets Diagnose the Condition

Diagnosis of UAP is primarily by your vet through clinical examination and imaging. X-rays usually reveal the ununited fragment on the ulna. If X-rays are inconclusive, a CT scan or elbow arthroscopy might be recommended to confirm diagnosis and assess joint damage.

Current Treatment Approaches

Early diagnosis improves treatment outcome. Surgery is the mainstay treatment and may involve reattaching the anconeal process or, if the joint is badly damaged, removing the detached fragment and performing procedures such as proximal ulnar osteotomy (PUO) to improve joint alignment and stability.

Post-operative care includes managing pain and ensuring proper nutrition to support healing. Without treatment, UAP worsens, leading to severe arthritis and functional loss, causing dogs to avoid using affected limbs or even become immobile if both elbows are affected.

Good Breeding Practices to Prevent UAP

Responsible breeders screen potential breeding dogs for elbow abnormalities such as UAP and avoid breeding affected animals. This reduces genetic transmission and helps raise healthier litters. Before adopting or purchasing a puppy of predisposed breeds, always ask for health screening documentation to ensure the pup’s lineage is free from UAP.