![]() The MCL is the primary stabilizer of valgus movements. The medial collateral ligament (MCL) and lateral collateral ligament (LCL) are the main capsuloligamentous stabilizers. ![]() ![]() Īs a triangular-shaped protrusion at the anterior facet of the proximal ulna, the coronoid process provides ulnohumeral stability anteriorly and a varus buttress while resisting posterior subluxation. Radial head fractures may be associated with episodic elbow instability, mechanical block to elbow motion, and injury to the distal radioulnar joint and/or the interosseous membrane (Essex-Lopresti). In an intact elbow, the radial radiocapitellar articulation contributes minimally to valgus stability however, in the event of MCL or coronoid injury, the radial head acts as the primary stabilizer to valgus stresses and also prevents elbow subluxation. The radial head is an important restraint to posterolateral rotatory instability (PLRI) and acts as a secondary valgus stabilizer. The elbow is comprised of three sub-joints - the humeroradial, humeroulnar, and superior radioulnar joints - further made up of the humerus, radius, ulna, and related capsuloligamentous structures. Successful evaluation and treatment require detailed knowledge of the functional importance and relationship of each bony and soft tissue component and its contribution to elbow stability. Standardized surgical protocols and novel algorithmic approaches attempt to improve outcomes for terrible triad patients. ĭespite clinical and operative advancements and an increased understanding of pathoanatomy and elbow biomechanics, controversies remain regarding the appropriate treatment algorithm. Fracture of the radial head, coronoid process, or olecranon inherently destabilizes the dislocation and nearly always mandates operative intervention to restore functional anatomic alignment and joint stability. On the other hand, complex elbow dislocations are defined by an association with fracture(s) of one or more major bony stabilizers. Owing to those mentioned above, even isolated elbow dislocations without bony fragmentation indicate substantial soft tissue injury with capsular and ligamentous disruption. The complex anatomical structure and higher functional requirements make treating the elbow more difficult. The historically poor outcomes and high complication rates portend the designation of this injury pattern as “terrible.” Provided its numerous bony and soft tissue structures, the elbow is well known as one of the most stable joints of the body. Originally described in 1996 by Hotchkiss, the terrible triad of the elbow constitutes a highly unstable form of fracture-dislocation consisting of elbow dislocation with concomitant radial head or neck and coronoid process fractures. This activity aims to provide readers with the tools necessary to appropriately examine and evaluate, diagnose, and treat terrible triad injuries operatively, with the care to continue close postoperative monitoring while following therapy protocols. Progression of pathologic, biomechanical, and clinical knowledge across the past few decades has permitted advancements in surgical approaches to restore stability, provide anatomical repair, enable early mobilization, and prevent the onset of stiffness. Given the elbow is the second most commonly dislocated joint in the upper extremity, with nearly 20% of dislocations associated with a fracture, the prevention of complications mentioned above requires an understanding of the dislocating forces that combine forearm rotation and valgus deformity unto an extended elbow while the forearm experiences axial compression. As a volatile form of fracture-dislocation consisting of elbow dislocation with concomitant radial head or neck and coronoid process fractures, the “terrible triad” of the elbow is a complex injury that, if not treated appropriately, can portend pain, stiffness, and post-traumatic arthritis.
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