What is the recommended evaluation, classification, and treatment protocol for a suspected radial head fracture?

Radial Head Fracture: Evaluation, Classification, and Treatment

Begin with plain radiographs of the elbow as the initial imaging study, which will identify the fracture in most cases and guide subsequent management decisions. 1

Initial Evaluation

Imaging Protocol

• Plain radiographs are the first-line imaging modality for suspected radial head fractures, as they identify fractures in approximately 50% of adult elbow injuries. 1

• Look for indirect signs of fracture on radiographs, including posterior and anterior fat pad elevation (indicating joint effusion), which in the context of acute trauma implies an occult elbow fracture even when no fracture line is visible. 1

• If radiographs are normal or indeterminate but clinical suspicion remains high, obtain CT without contrast to identify occult fractures and clarify fracture morphology. 1 Studies show that 12.8% of patients with equivocal radiographs and inability to fully extend the elbow have occult fractures on CT. 1

• CT provides critical surgical planning information, including fragment size, displacement, angulation, and identification of associated injuries (Essex-Lopresti, Monteggia fractures). 1

Critical Associated Injuries to Assess

Always evaluate for associated injuries, as these determine management more than the radial head fracture pattern alone. 2, 3

• Assess for ligamentous injuries: lateral collateral ligament complex, medial collateral ligament, and anterior capsule disruption. 1

• Look for associated fractures: coronoid process, olecranon, medial/lateral epicondyles. 1

• Recognize complex injury patterns: terrible triad (radial head fracture + coronoid fracture + elbow dislocation), posterior fracture-dislocation, Essex-Lopresti injury (radial head fracture + interosseous membrane disruption + distal radioulnar joint injury). 1

• Comminution and complete loss of cortical contact in at least one fragment are red flags for associated injuries requiring more aggressive treatment. 3

Classification

The Modified Mason classification remains the standard, incorporating associated injuries:

• Type I: Nondisplaced or minimally displaced (<2 mm) fractures 2, 4, 5
• Type II: Displaced (>2 mm) fractures with a single fragment 2, 5
• Type III: Comminuted fractures 2, 5
• Type IV: Radial head fracture with elbow dislocation 2

This classification is only useful for isolated radial head fractures without associated injuries—complex injuries require different treatment algorithms. 6

Treatment Protocol

Mason Type I (Nondisplaced or <2 mm Displacement)

Treat conservatively with early mobilization, as outcomes are excellent. 2, 4, 5

• Consider joint aspiration if significant hemarthrosis is present. 4

• Immobilize in a broad arm sling for 2 days only, then begin early range of motion. 4

• At first outpatient visit (within 1 week), assess collateral ligament stability and encourage active stretching beyond the painful range if the elbow is stable. 4

• Discharge patients at the first visit with instructions to return only if no improvement at 6 weeks. 7, 4 Studies show 96% patient satisfaction with this approach and only 1% require late surgical intervention. 7

• No routine radiographic follow-up is needed unless clinical deterioration occurs. 7, 4

Mason Type II (Displaced >2 mm)

Perform open reduction and internal fixation if there is mechanical block to pronation/supination or displacement >2 mm with associated injuries. 2, 5, 3

• Headless cannulated screws are preferred for fixation, providing satisfactory biomechanical stability through smaller incisions with fewer complications. 2

• Plate fixation is reserved for fractures with neck comminution. 2

• If no mechanical block exists and no associated injuries are present, displacement alone (>2 mm) is not an absolute indication for surgery—consider conservative management in select cases. 3

Mason Type III (Comminuted)

The treatment decision depends critically on associated injuries, not the fracture pattern alone. 2, 5, 6

For Isolated Fractures (No Associated Injuries):

• Radial head excision is acceptable in elderly patients with isolated comminuted fractures. 2, 5, 6

For Complex Injuries (Associated Ligamentous or Bony Injuries):

• Radial head arthroplasty is preferred over excision in younger patients or when significant soft tissue/bony injuries are present, as the radial head is a critical secondary stabilizer. 2, 5, 8

• Attempt internal fixation if technically feasible, but if the fracture is unfixable, proceed with prosthetic replacement rather than excision. 2, 5

• Surgeons typically recommend arthroplasty for older patients, whole-head fractures, and fractures with >3 fragments. 9

• Reoperation rates are similar (1-2.5%) across all surgical treatment modalities. 8

Mason Type IV (With Elbow Dislocation)

Treat as a complex injury requiring surgical stabilization of both the radial head and associated injuries. 2, 6

• Reconstruct or temporarily fix the radial pillar to prevent ulnohumeral subluxation and late radioulnar instability. 6

• Address all components of terrible triad injuries (radial head, coronoid, lateral collateral ligament). 1

Key Pitfalls to Avoid

• Never excise the radial head in the presence of ligamentous injuries without prosthetic replacement, as this leads to instability. 5, 6

• Do not miss Essex-Lopresti injuries—always assess the distal radioulnar joint clinically and radiographically. 1

• Coronoid fractures indicate prior dislocation—always assess for associated soft tissue injuries. 1

• Avoid prolonged immobilization in Type I fractures, as early mobilization (after 2 days) produces superior outcomes. 4