Review Question - QID 219798

This 34-year-old male sustained a comminuted radial head fracture following a motorbike accident, with subsequent forearm instability and proximal migration of the radius, suggesting an Essex-Lopresti Injury. The radial head is the most important stabilizer to prevent proximal migration of the radius and overall longitudinal stability of the forearm (Answer 4).

Essex-Lopresti Injuries (ELI) are uncommon injuries stemming from axial loads and are more often missed than diagnosed at the time of initial presentation. A high suspicion should be had for the injury, with the entity frequently being present in seemingly innocuous-appearing radial head fractures. ELIs entail a unique combination of injuries, which includes a radial head fracture, interosseous membrane (IOM) disruption, and distal radioulnar joint (DRUJ) disruption. All three components of the injury are necessary to create longitudinal instability of the forearm, however, the radial head (followed by the interosseous membrane) remains the most important anatomical consideration to prevent proximal migration of the radius.

Loeffler et al. provide an anatomical and biomechanical review of the forearm, while also examining the history, diagnosis, and management of ELIs. The authors note that ELIs are commonly missed, and diagnosed correctly at a mere 25% of the time at the initial presentation. Moreover, they note the radial head, IOM, and triangular fibrocartilage complex (TFCC)/DRUJ contribute to axial stability and ultimately adequate pronosupination of the forearm. The authors note an intraoperative "radius pull test" can be performed to assess the longitudinal stability of the radius, with > 3 mm proximal migration indicative of IOM disruption, while > 6 mm proximal migration is suggestive of both IOM and TFCC disruption, thereby serving as a contraindication for radial head excision.

Dr. Adams provides a review of the various injuries resulting in forearm instability, which includes Galeazzi fracture-dislocations, Monteggia fracture-dislocations, and ELIs. The author notes accurate diagnosis is paramount to facilitate good outcomes for ELIs, which primarily includes open reduction, internal fixation (ORIF) versus radial head replacement with radial head fractures, and TFCC repair if DRUJ disruption is present. In the event of a missed ELI, ulnar impact syndrome secondary to ulnar-positive variance is often seen, which results in wrist impingement, forearm pain, weakness, and/or instability, and is subsequently treated with a joint-leveling procedure to improve joint biomechanics.

Matson and Ruch examine the anatomy, mechanism, examination, and management of ELIs. For radial head fractures, the authors recommend ORIF versus radial head replacement. Concerning IOM repair, numerous techniques are present, including direct repair, tightrope fixation, autograft, and allograft, with the authors recommending direct repair when possible. Ultimately, the authors stress the importance of prompt diagnosis, noting poor outcomes in patients treated in a delayed fashion, with only 20% achieving satisfactory outcomes, whereas 80% diagnosed and treated acutely experienced good outcomes.

Figures A-D represent orthogonal views of the elbow and wrist, demonstrating a radial head fracture and DRUJ disruption secondary to ulnar head dislocation, collectively suggesting an ELI.

Incorrect Answers:
Answers 1, 2, 3, 5: while all important in maintaining forearm stability, they do not play the largest role in preventing proximal radius migration.