Radial Head Fracture: Mason Classification and Early Active Mobilization

Radial head fractures constitute approximately thirty-three percent of all adult elbow fractures and over ten percent of all traumatic elbow dislocations. The injury classically results from a fall onto an outstretched hand (FOOSH) with the forearm in pronation and the elbow partially flexed, driving the radial head against the dense subchondral bone of the humeral capitellum. The radial head functions not merely as an articular contact surface for forearm rotation, but as the critical secondary bony stabilizer of the elbow against valgus stress and axial proximal migration of the radius. Prolonged immobilization of the elbow following a radial head fracture frequently results in severe, disabling capsular contracture. Modern orthopedic and physiotherapy consensus strongly advocates for immediate clinical stratification using the Mason classification to initiate safe, early active mobilization.

Monsoon Slips, Two-Wheeler Skids, and Household Tumbles

Across India, radial head fractures occur with remarkable frequency during the annual monsoon season when wet tiled verandas, slick marble indoor floors, and slippery road surfaces cause sudden pedestrian falls. Commuters falling from two-wheelers on oil-slicked roads or slipping on uneven brick steps in residential areas instinctively land on an outstretched palm. In domestic households, elderly individuals navigating dimly lit stairways or homemakers cleaning wet bathroom surfaces frequently sustain low-energy FOOSH impacts. Failing to mobilize the injured arm within the first week leads rapidly to profound elbow stiffness, preventing individuals from bringing food to their mouth or washing their hair independently.

Mason Fracture Morphology, Essex-Lopresti Injury, and Biomechanics

In 1954, Dr. Mark Mason classified radial head fractures into three core categories, later expanded by Johnston to include a fourth category. Type I fractures are non-displaced or minimally displaced (less than two millimeters of displacement) without mechanical block to forearm rotation. Type II fractures are displaced partial-articular fractures involving more than thirty percent of the head or greater than two millimeters of step-off. Type III fractures are severe, comminuted fractures involving the entire radial head. Type IV fractures represent any radial head fracture accompanied by a humeroulnar joint dislocation. In high-energy injuries, clinicians must always palpate the distal radioulnar joint (DRUJ) at the wrist to rule out an Essex-Lopresti injury, which involves concurrent rupture of the interosseous membrane and destabilizes the entire forearm longitudinal axis.

Early Active Motion Protocols, Edema Evacuation, and Sling Weaning

For stable Type I and select non-displaced Type II fractures, non-operative treatment with immediate early active mobilization yields superior long-term functional arcs compared to cast immobilization. A supportive sling is worn strictly for comfort during the initial forty-eight to seventy-two hours, with active hand pumping and gentle active-assisted elbow flexion and extension initiated on day three. Forced passive stretching is strictly prohibited, as forceful manipulation causes painful reflex muscle spasm and provokes heterotopic ossification within the brachialis muscle. Physiotherapy focuses on active range of motion within the patient’s pain-free tolerance, combined with ice therapy and gentle soft tissue drainage. For Mason Type III and IV injuries managed with open reduction internal fixation (ORIF) or modular radial head arthroplasty, active motion begins within seven days post-surgery once wound stability is verified.

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