Review Question - QID 220503

This patient suffered a lateral ulnar collateral ligament (LUCL) injury and now has posterolateral rotatory instability of his elbow. The exam maneuver commonly reproducing the most pain in this injury is the lateral-pivot shift test, which involves bringing the elbow from full extension to 40 degrees of flexion while placing a valgus stress on the elbow with forearm supination (Answer 3).

Elbow LUCL injuries involve disruption to the elbow's lateral collateral ligament (LCL) complex and are associated with a traumatic elbow dislocation. The LCL complex consists of the accessory lateral collateral ligament, annular ligament, LCL, and LUCL. The LUCL is the primary stabilizer against varus and external rotation stress. This presents with posterolateral subluxation of the radiocapitellar and/or ulnohumeral joint(s). Typically, the cascade of movements when rising from a seated position and pushing off an object places the elbow in forearm supination, axial loading, and valgus stress, with the elbow in full extension, causes progressive failure of the LCL complex. When a traumatic mechanism is present, the LCL complex most commonly fails at the humeral origin on the lateral epicondyle. Treatment consists of conservative management with splint or sling immobilization at 90 degrees of elbow flexion (or level of stability), operative management with fracture fixation (if present), and LUCL repair/reconstruction.

Noriego et al. performed a cadaveric study evaluating the LUCL in 55 elbows. They found the total length of the LUCL was 48.50 mm at 90°, 46.76 mm at maximum flexion, and 44.10 mm at complete extension. They also report that the LUCL is closely related to the annular ligament and is stretched during flexion and supination. They conclude that this study helped to provide the anatomical data for surgeons who regularly repair these ligaments.

Fukai et al. performed a cadaveric study of 24 elbows (12 right and 12 left) to analyze the thickness of the LUCL using micro-CT quantitatively. The supinator aponeurosis and joint capsule formed a thick membrane (mean and standard deviation, 4.8 ± 1.2 mm). They found this was thicker than the anterior (1.3 ± 0.4 mm) and posterior (2.5 ± 0.9 mm) portions of the capsule in the radiocapitellar joint (p < 0.001). They noted this thick membrane is attached to the humeral origin of the EDC/EDM, the lateral aspect of the coronoid, and the posterior radial notch of the ulna. They conclude that the entire structure appeared identical to the commonly defined LCL. The most posterior part was connected to the EDC and ECU aponeuroses, which are commonly labeled the LUCL but do not exist as a discrete ligament.

Zhang et al. performed a retrospective study in 2014-2019, analyzing 24 patients with elbow posteromedial rotatory instability (PMRI) who underwent surgery. 15 patients had their LUCL surgically repaired, and 9 did not. They reported that mean blood loss (184.66 ± 20.3 vs 207.33 ± 19.447, P < 0.001) and operation time (98.88 ± 12.693 min vs 184.66 ± 20.3 min, P < 0.001) were significantly lower in the repair group. No significant differences were reported in MEPS or DASH scores at final follow-up. No significant differences were found between the two groups in time until surgery and follow-up (6.7 vs 6.1 days, 25.5 vs 26.11 months, P = 0.577, P = 0.486). They conclude that satisfactory outcomes can be achieved in patients with elbow PMRI without repair of the LUCL as long as there is a stable joint.

Figure A is a coronal T2 MRI of the right elbow demonstrating an LCL tear. Illustration A is an anatomical image depicting the LUCL complex in the elbow.

Incorrect answers:
Answer 1: Resisted long finger extension is a provocative maneuver for lateral epicondylitis.
Answer 2: Pain with hooking the biceps tendon at the elbow could be present with biceps tendinopathy.
Answer 4: The milking maneuver in the elbow is more commonly associated with an MUCL injury.
Answer 5: Valgus stress to the elbow is more commonly associated with MUCL injuries.