Review Question - QID 220031

This 54-year-old female sustained a comminuted right radial head fracture. Radial head resection is contraindicated secondary to interosseous membrane disruption based on excessive proximal migration with intraoperative pull testing (Answer 5).

Radial head fractures are injuries that commonly stem from falls onto an outstretched hand. While simple, intra-articular fractures with minimal step-off and no block to motion can be treated non-operatively, higher-energy fractures, which result in increasingly comminuted fractures, typically necessitate operative treatment, with varying techniques. Open reduction internal fixation (ORIF) can be attempted in fractures with three or fewer fragments, but the option becomes technically challenging and has demonstrated inferior outcomes when utilized for fractures with more than three fragments. Because of this, radial head replacement or excision is often the treatment of choice. The latter is typically reserved for older patients who are lower demand. However, when there is suspicion for an interosseous membrane disruption, as suggested by a positive radius pull test (normal is < 3 mm), radial head resection is contraindicated to prevent proximal migration of the radius and therefore pathologic loading of the carpus onto the ulna.

Ring et al. performed a retrospective review of 56 patients undergoing ORIF of their radial head fractures, 30 of which had Mason type II fractures (15 exhibited comminution), while 26 had Mason type III fractures (14 exhibited comminution). Unsatisfactory results, which included failure fixation and/or less than a 100-degree arc of forearm pronosupination, were observed in 93.3% and 100% of comminuted type II and III fractures, respectively. The authors conclude that ORIF should be reserved for radial head fractures with minimal comminution.

Bain et al. provide a retrospective review examining the outcomes of 16 patients undergoing radial head replacement after sustaining a Mason type III radial head fracture. At an average of 2.8 years, 50% exhibited an "excellent" result based on Mayo Elbow Performance Scores. A mean flexion contracture was noted to be 15 degrees, while a 12-degree loss of pronosupination was found. The authors noted patients who underwent delayed replacement experienced the most significant losses in range of motion. As such, they conclude radial head replacement can provide satisfactory outcomes in Mason type III fractures if performed within a reasonable time frame and in conjunction with early range of motion.

Figures A and B represent an AP and lateral of the right elbow demonstrating a comminuted radial head fracture with minimal evidence of elbow subluxation/dislocation.

Incorrect Answers:
Answer 1: While this fracture demonstrates comminution, it is reasonable to attempt ORIF if fracture fragments allow so. Moreover, longitudinal instability of the forearm would be mitigated with repair of the radial head.
Answer 2: Lateral collateral ligament disruptions result in posterolateral rotatory instability of the elbow, and have no role in longitudinal stability.
Answer 3: The anterior capsule plays a role in sagittal stability of the elbow, and is most commonly compromised in elbow dislocations.
Answer 4: Radial head replacement would be indicated in this scenario to prevent proximal migration of the radius.