Posterolateral Rotatory Instability of the Elbow: A Practice-Focused Narrative Review

Posterolateral rotatory instability (PLRI) is the most common pattern of elbow instability and an underdiagnosed cause of persistent lateral elbow pain. Under-recognition is common because radiographs may be normal, and the instability is dynamic. This narrative review synthesises contemporary evidence on the lateral collateral ligament (LCL) complex, with emphasis on the lateral ulnar collateral ligament (LUCL), and integrates applied anatomy, pathomechanics, clinical presentation, examination, imaging choices, and management. Diagnosis is primarily clinical, led by history and provocative testing and supported by targeted static imaging (plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI)) and by dynamic modalities (fluoroscopy or ultrasound) when static studies are equivocal. Conservative non-operative care comprises activity modification, targeted physiotherapy, and time-limited bracing for low-grade, low-demand, and improving cases. Symptomatic or chronic instability is treated with anatomic LUCL reconstruction (autograft or allograft) with attention to surgical technique and early protected motion. Early recognition and intervention improve functional recovery and reduce recurrent instability. Contemporary series report good-to-excellent outcomes in approximately 85 to 90% with a high return to activity when rehabilitation is structured. Special considerations are required in deformity-driven cases such as cubitus varus, where corrective osteotomy may be required in addition to ligament reconstruction. Practical pathways for diagnosis and treatment are presented to reduce missed diagnoses and improve outcomes through timely recognition and appropriate intervention. A comprehensive literature search of peer-reviewed articles was performed using PubMed and Medical Literature Analysis and Retrieval System Online (MEDLINE) without date limits, focusing on seminal and contemporary literature and supplemented by manual reference screening.