Review Question - QID 217903

This patient has a comminuted radial head fracture with a lateral collateral ligament complex injury (as indicated by the bare lateral humeral epicondyle). After addressing the lateral side, rehabilitation should involve elbow extension exercises with the forearm pronated.

Radial head fractures most commonly occur as a result of a valgus posterolateral rotary load across the elbow. In addition to a radial head fracture, a concomitant lateral ulnar collateral ligament (LUCL) injury is often present; it is most commonly avulsed from the humeral epicondyle. LUCL injury is a ligamentous elbow injury usually associated with a traumatic elbow dislocation and characterized by posterolateral subluxation or dislocation of the radiocapitellar and ulnohumeral joints. In the acute setting, the radial head is often fixed or replaced, and the LUCL should be repaired. Postoperatively, elbow extension exercises should be performed with the forearm in pronation as a result of the compromised LUCL. This positioning places the least stress on the ligamentous repair.

Yoon et al. reviewed radial head fractures and their associated ligamentous, cartilaginous, or other bony injuries. They reported that undisplaced or minimally displaced fractures with no rotational block to motion can be treated nonoperatively with excellent results expected. They concluded that medium-term data suggest that patients with comminuted radial head fractures do well with radial head replacement.

Armstrong et al. reviewed the relative contribution of muscle activity and the effect of forearm position on the stability of the MUCL-deficient elbow. They reported that compared with the intact elbow, transection of the MUCL, with the arm in a vertical orientation, caused a significant increase in internal-external rotation during passive elbow flexion with the forearm in pronation, but forearm supination reduced this instability. They concluded that splinting and passive mobilization of the MUCL-deficient elbow with the forearm in supination should minimize instability and valgus elbow stresses should be avoided throughout the rehabilitation period.

Dunning et al. reviewed the influence of muscle activity and forearm position on the stability of the LUCL-deficient elbow. They reported that in the vertical orientation during passive elbow flexion, stability of the LUCL-deficient elbow was similar to the intact elbow with the forearm held in pronation, but not similar to the intact elbow when maintained in supination. They concluded that the stabilizing effect of muscle activity suggests physical therapy of the LUCL-deficient elbow should focus on active rather than passive mobilization, while avoiding shoulder abduction to minimize varus elbow stress, and passive mobilization should be done with the forearm maintained in pronation.

Figure A is of an elbow fracture–dislocations that presented with a complete avulsion of the lateral collateral ligament complex off the lateral humeral epicondyle. Illustration A shows a repair using with two heavy nonabsorbable sutures through the substance of the lateral collateral ligament complex and the lateral humeral epicondyle. The sutures follow the lines of tension of the lateral ulnar collateral ligament. The sutures are partially placed through the common extensor-supinator group to augment the repair. They are then passed through bone tunnels at the isometric point into the humeral epicondyle.

Incorrect Answers:
Answer 1: No elbow motion for 6 weeks would result in significant elbow stiffness and is not recommended.
Answer 2: Elbow extension exercises in supination are recommended for compromise of the medial ulnar collateral ligament (MUCL).
Answer 3: Elbow extension exercises in neutral are recommended for compromise of both LUCL and MUCL injuries.
Answer 5: Postoperative elbow extension exercises are influenced by which anatomical structures were addressed surgically.