Radial Head Fracture Classification

Type I

• <2mm displacement, or marginal lip fracture
• No mechanical block to rotation
• Treatment: Posterior splint for 1 week followed by early active range of motion.
• Consider hematoma aspiration and local anesthetic injection to fully assess ROM if evaluation is limited by pain.
• Consider static progressive nightime extension splinting if a flexion contracture is present 6 weeks after injury.
• (Liow RY, Injury 2002;33:801)

Type II

• >2mm displacement, amendable to fixation
• May have mechanical block to motion
• Treatment: examination under anesthesia. IF mechanical block to motion, or joint instability or displacement >3mm=ORIF; if stable, <3mm displaced with full ROM nonop treatment indicated.
• 82% of patients are asymptomatic at 19yrs with non-op treatment (Akesson T, JBJS 2006;88A:1909).
• Determination of Type II or Type III fracture type can often only be made intraoperatively.
• Have radial head replacement available.

• Displaced, severely comminuted
• Not amendable to fixation
• Treatment: excision (Herbertsson P, JBJS 2004;86A:1925) vs Radial Head Replacement (Moro JK, JBJS 2001;83A:1201).
• Excision alone is contraindicated when either medial collateral ligament or interosseous membrane disruption is present. Either replacement or reconstruction is indicated in these cases. 
• If distal ulnar instability is present, it is best to pin the ulna to the radius with the forearm in supination

• Same as type III with associated elbow dislocation.

Mason Classification

• Type I=undisplaced=best prognosis.  Immobilization for 1wk followed by an active ROM program beginning within 1wk to minimize long-term stiffness. (Weseley Ms, JOT 1983;23:36).
• Type II=displaced wedge fragments= best indication for surgery.
• Type III-comminuted=internal fixation should not be done in an individual older than 50 yrs, in an isolated injury, or in a fracture that is too comminuted to be fixed

AO Classification