Canine Elbow Dysplasia

Canine Elbow Dysplasia

Canine elbow dysplasia is an umbrella term for several congenital abnormalities that are recognized in the elbow. A dog with elbow dysplasia may be affected with one or more of the following: Ununited anconeal process (UAP), osteochondrosis dissecans (OCD) of the humeral condyle, fragmentation of the medial coronoid process (MCP), and elbow incongruity.

Key Points (if applicable)

• Be familiar with the common breeds affected
• This is a young dog disease which will lead to degenerative osteoarthritis without treatment
  • Sometimes the best you can do is slow down the progression
• Elbow will be painful on manipulation (especially flexion and extension)
• Look for sclerosis of the ulna and degenerative changes above the anconeal process as a tip-off for potential fragmentation of the MCP

Ununited Anconeal Process

Common Breeds:

• German Shepherds, Bassett Hound, Bloodhound, Labrador Retrievers, Newfoundlands

Clinical Signs:

• Usually by 4-12 months of age
• Forelimb lameness

o Pain on flexion and extension of elbow joint

• May be bilateral but not necessarily

o Screen for disease on other side

Diagnosis:

• Radiograph

• • Physis should be closed by 4-5 months of age

• Visualize ununited anconeal process best on flexed lateral projection
• Anconeal center of ossification fails to fuse to the ulna
• CT

Treatment:

• Can try medical management with NSAIDS but usually unrewarding
• Excision of anconeal process seems to provide most consistent results
• Lag screw fixation and proximal ulnar ostectomy have also been reported

OCD of the Humeral Condyle

• Definition- Abnormal endochondral ossification resulting in thickening of the articular cartilage
• Growth rate, genetics, hormonal imbalance, and diet are potential factors

Common Breeds:

• German Shepherds, Golden Retrievers, Labrador Retrievers, Newfoundlands, Rottweiler.

Clinical Signs:

• Usually by 4-7 months of age
• Bilateral disease at least 50% of the time
• Forelimb lameness
• Pain on flexion and extension of elbow joint

Diagnosis:

Radiographs

• • See lesion on medial aspect of humeral trochlea
  • May see visible flattening
  • Subchondral bone defect and surrounding sclerosis
  • Osteophytosis
• CT
• Arthroscopy 

Treatment:

• Medical management not effective
• Surgery
• Surgical removal of flap and debridement of subchondral bone gives fair to excellent results with most dogs
• Typically performed arthroscopically
  • Allows better visualization of the lesion

Medial Fragmented Coronoid Process (FCP)

Common Breeds:

• Labrador Retrievers, Golden Retrievers, Newfoundlands, Rottweilers

Clinical Signs:

• Usually by 4-7 months of age
• Forelimb lameness
• Painful on flexion and extension of elbow
• May be bilateral

Diagnosis:

• Radiographs
• It is hard to definitively visualize the fragment.
  • So you usually must go by typical secondary changes that are associated with a FCP.
  • Get a view of the other elbow for comparison and to ensure there is no disease on the other side
  • Sclerosis of subchondral bone along trochlear notch of the ulna and adjacent to the proximal radioulnar articulation near the lateral coronoid process
  • Medial coronoid process may be large, blunted, or have osteophyte associated with it on the lateral view.
  • Proliferative bone may develop on the proximal anconeus
  • Degenerative joint disease
  • Concurrent elbow incongruency
• CT
• Arthroscopy

Treatment:

• Medical therapy likely not effective
• Surgical removal of the fragment or arthroscopy for removal of fragment are most common treatments
• Most surgeons perform this arthroscopically

Elbow Incongruity

• Term to describe poor alignment of the joint surfaces of the elbow
• Two features illustrate incongruity of the elbow:   o   Abnormal shape of the ulnar trochlear notcho   Step between the radius and ulna, caused by either a short radius or a short ulna
• Very difficult to diagnose due to radiographic positioning and subjectivity

o   Some advocate CT evaluation instead

• Some advocate CT evaluation instead
• Clinical signs and breed predispositions are the same as above
• Not as well described as other elbow dysplasia conditions
• Some people speculate that elbow incongruency leads to the other players in elbow dysplasia
• Treatment involves performing an ulnar osteotomy; however, there is come controversy as to how effective it may be.