luxatio

Luxatio, or luxation, refers to the complete displacement of a bone from its joint, resulting in a loss of contact between the articular surfaces. It is distinguished from subluxation, in which contact is only partially maintained.

Etymology: The term luxation derives from the Latin luxatio, meaning dislocation.

Common joints affected include the shoulder (the most frequent), the patellofemoral joint of the knee, the elbow, the hip, and certain joints of the fingers and the jaw (temporomandibular joint). Luxation can result from direct trauma, falls, or high-energy injuries, and may be associated with fractures or ligamentous injuries. Congenital laxity and degenerative joint disease can predispose to luxation as well.

Clinical presentation includes sudden severe pain, deformity or abnormal contour, swelling, and loss of functional movement. Neurovascular status should be assessed urgently because injury to nerves or vessels may accompany a luxation. Diagnosis is usually confirmed by radiographs; CT may delineate associated fractures and displacements; MRI can assess soft-tissue injuries when needed.

Management begins with careful assessment and analgesia or anesthesia for reduction. Closed reduction is attempted for many joints using joint-specific maneuvers, followed by immobilization or bracing and a structured rehabilitation program. Post-reduction imaging confirms alignment and rules out missed fractures. If reduction is not possible, if there are associated fractures, or if instability recurs, surgical treatment may be required.

Prognosis depends on the joint involved, the mechanism, and promptness of reduction. Complications include neurovascular injury, recurrent instability (notably in the shoulder), avascular necrosis after hip dislocation, post-traumatic arthritis, and stiffness.