# Elbow Dislocation > Elbow dislocation for NEET-PG Orthopaedics: posterolateral rotatory mechanism, simple versus complex injury, brachial artery checks and early motion after reduction. - Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/elbow-dislocation - Exam / course: NEET-PG · Subject: Orthopaedics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-08 - Last updated: 2026-10-08 - Reference basis: Rockwood and Green's Fractures in Adults; Campbell's Operative Orthopaedics; Apley's System of Orthopaedics and Fractures - How to cite: "Elbow Dislocation", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/elbow-dislocation ## Direct answer An elbow dislocation is displacement of the ulna and radius relative to the humerus, and the posterolateral rotatory mechanism, a fall on an outstretched hand with a rotatory force, is the commonest variant. A simple dislocation has no associated fracture, while a complex one includes radial head or coronoid fractures. Closed reduction usually succeeds, but neurovascular examination, especially of the brachial artery and nerves, must precede and follow it. ## What you must remember - **Posterolateral rotatory:** the commonest pattern; the lateral collateral ligament fails first, and the ulna then rotates posterolaterally relative to the humerus. - **Simple dislocation:** no fracture; recovery is usually good, and early motion is the usual plan after stable reduction. - **Complex dislocation:** an associated radial head, coronoid or other fracture, which adds instability and changes the plan. - **Neurovascular status:** the brachial artery and the median, ulnar and radial nerves are checked before and after reduction, with pulse, capillary refill and sensation recorded. - **Reduction:** closed reduction by longitudinal traction, flexion and forearm position usually relocates the joint, ideally soon after injury. - **Post-reduction films:** radiographs in two planes confirm the reduction and look for coronoid and radial head fractures. - **Instability:** persistent instability on stress testing points to lateral collateral ligament insufficiency, which is repaired or reconstructed. ## A pathway from reduction to rehabilitation Management is decided after reduction, when the stability and the associated fractures become clear. Each step checks a different risk. 1. **Document neurovascular status:** record the radial pulse, capillary refill and median, ulnar and radial nerve function before reducing the joint. 2. **Reduce under sedation:** longitudinal traction, flexion and forearm positioning relocate the joint, with checks repeated afterwards. 3. **Confirm position and fractures:** radiographs in two planes confirm the reduction and show any coronoid or radial head fracture. 4. **Test stability:** the elbow is stressed through its range after reduction to decide between early mobilisation and surgery. 5. **Mobilise:** a simple, stable dislocation is moved early, often in a hinged brace, to limit stiffness. 6. **Operate for instability:** lateral collateral ligament repair or reconstruction, along with fixation of any fracture, addresses persistent instability. The exam tests the mechanism, the neurovascular check and the distinction between simple and complex injury. Early motion is the principle that most often surprises candidates who were taught long immobilisation. ## Where the exam tries to catch you A dislocated elbow is a common vascular and neurological hazard, and the questions often hinge on what was checked. - **Trap:** attributing a cold, pale hand after reduction to swelling and missing brachial artery injury — **Correct:** check the pulse and perfusion before and after reduction, and act on any loss of perfusion. - **Trap:** immobilising a simple elbow dislocation in plaster for several weeks — **Correct:** early motion after stable reduction reduces stiffness, which is the main long-term problem. - **Trap:** missing a radial head or coronoid fracture on the post-reduction film — **Correct:** a complex dislocation changes the plan, so the films must be examined for associated fractures. ## Frequently asked questions ### What is the commonest mechanism of elbow dislocation? The posterolateral rotatory mechanism, a fall on an outstretched hand with the forearm supinated and a rotatory force, is the commonest. It damages the lateral collateral ligament first, allowing the ulna to displace posterolaterally. ### What is the difference between simple and complex elbow dislocation? A simple dislocation has no associated fracture, while a complex dislocation involves fractures such as the radial head or coronoid process. Complex dislocations carry more instability and usually need more careful follow-up. ### Which vessel and nerves must be checked in elbow dislocation? The brachial artery and the median, ulnar and radial nerves must be checked before and after reduction. Pulse, capillary refill and sensory and motor function document the initial state and reveal any new deficit. ### When is surgery needed after elbow dislocation? Surgery is considered for persistent instability on stress testing, an irreducible dislocation, or associated fractures that need fixation. Lateral collateral ligament repair or reconstruction addresses posterolateral rotatory instability.