- Failure of separation of proximal radius and ulna
- Familial (? dominant)
- Bilateral in 60% of cases
- Frequently associated with other muscular abnormalities and foetal alcohol syndrome
Clinically
Fixed pronation of forearm
X-Rays
May have proximal radio-ulnar fusion with proximal radial abnormality or dislocated radial head
Treatment
- Rarely indicated for functional reasons and excision of union always fails
- Osteotomy through the level of the synostosis when pronation is greater than 45 degrees with rotational correction to improve function
- Unilateral : aim for ~ 20 degrees pronation
- Bilateral
- Non dominant : correct to neutral
- Dominant : correct to 30 pronation
Complications
- Non-union
- Neurovascular problems
- Inadequate correction