Usually caused by a fall onto an outstretched hand with the forearm pronated.
Accounts for 30% of elbow fractures.
Associated with a variable degree of comminution and displacement depending on compressive forces.
May be associated with surrounding soft tissue injury.
10% of cases associated with elbow dislocation.
Mason classification-type I-no associated injuries, type II-displacement with more than 30% of the radial head involved, type III-comminuted fracture and involvement of the entire radial head, and type IV radial head fracture with elbow dislocation.
Complaints of pain on the lateral side of the elbow.
Impaired mobility with loss of pronation and supination.
Examination reveals tenderness over the radial head and often joint effusion.
The distal radio-ulnar joint must be checked for interosseous membrane disruption, the Essex-Lopresti injury.
AP and lateral x-rays usually reveal type II an III fractures while type I, nondisplaced, fracture may not be noticed.
If a fracture is suspected , but not visualized a repeat radiograph should be taken in about 2 weeks.
A fat pad sign may be seen on x-rays and this suggests the presence of a hemarthrosis.
Type I fracture is treated with a sling for 3-7 days followed by full range of motion exercises.
If hemarthrosis is large, aspiration for comfort is indicated.
If the fragment is less than 30% of the radial head and is displaced less than 2 mm and there is no mechanical block to elbow or forearm motion, type II fractures can be treated with a sling.
If type II fracture is greater than 30% of the radial head and is displaced more than 2 mm surgery is indicated.
Comminuted fracture of the radial head, type III fracture, is treated with surgery.
Surgery involves excision of the radial head, with or without insertion of a radial head prosthesis.