Fractures of the radial head are the most common fractures involving the elbow in adults and most commonly occur secondary to a fall on outstretched hand (FOOSH). Exam typically involves pain to palpation over the radial head, limited extension and restriction of rotation. Diagnosis is easily accomplished with plain radiography, don’t forget to get a radiocapitellar view (lateral taken at 45 degrees) if a radial head fracture is suspected. Look for associated fractures of the capitellum, trochlea, coronoid and wrist. Point tenderness over the lateral or medial epicondyle might indicate a lateral/medial collateral ligament injury. The joint should be checked for range of motion (ROM) to flexion/extension as well as supination/pronation. If the elbow has a limited ROM a intra-articular aspiration and injection of several milliliters of lidocaine should done and the joint re-examined for range of motion.
Radial head fractures are classified using the Mason system. Mason type I (< 2mm displacement, less than 2 fragment fractures, without restriction to range of motion) are generally treated conservatively and can be managed in the primary care setting. Treatment consists of a sling for comfort and early active range of motion. Re-imaging is needed in 1-2 weeks to ensure appropriate alignment. Full extension and forearm rotation should be mildly limited by 6 weeks after injury. If ROM is not progressing, a mechanical block should be excluded. This approach is reported to have good results in >85% of patients.
All other Mason classification fractures will need orthopedic referral for ORIF or radial head replacement.
CLINICAL PEARL: Posterior fat pads are always pathologic. The presence of a sail sign or a posterior fat pad is evidence of a fracture or other intra-articular process. If a fracture is highly suspected and these findings are present the arm should be splinted/casted and re-imaged in 10-14 days.