A 28-year-old rugby player sustains a posterior dislocation of the elbow. After closed reduction, examination reveals instability in the lateral pivot-shift test. The primary soft tissue restraint injured in posterior elbow dislocation that must be reconstructed for persistent instability is:

• A Medial collateral ligament — anterior band
• B Lateral ulnar collateral ligament (LUCL) — the primary restraint to posterolateral rotatory instability ✓
• C Radial collateral ligament proper
• D Annular ligament of the radial head

Explanation

Posterolateral rotatory instability (PLRI) of the elbow results from insufficiency of the lateral ulnar collateral ligament (LUCL) — a specific component of the lateral collateral ligament complex running from the lateral epicondyle to the supinator crest of the ulna. The O'Driscoll lateral pivot-shift test (applying valgus, supination, and axial load to the semiflexed elbow) reproduces subluxation of the radial head posterolateral to the capitellum and is the clinical correlate. The MCL (anterior band) is the primary restraint to valgus stress; its injury causes valgus instability. Surgical reconstruction of the LUCL (using palmaris longus tendon graft from the lateral epicondyle to the supinator crest) is required for chronic PLRI.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.