Title : Postero Lateral Rotatory Instability (PLRI) of the elbow: Current concepts and the overlooked role of cubitus varus
Abstract:
Background: PosteroLateral Rotatory Instability (PLRI) is the most common form of chronic elbow instability, typically resulting from disruption of the lateral ulnar collateral ligament (LUCL). Although well described, it is frequently underdiagnosed due to subtle clinical findings and normal radiographs. Emerging evidence also highlights an association between chronic cubitus varus (“gunstock deformity”) and progressive ligamentous attenuation, predisposing patients to late-onset PLRI.
Methods: We reviewed current evidence on the pathoanatomy, biomechanics, diagnosis, and treatment of PLRI, with particular attention to its relationship with coronal plane deformity.
Results: PLRI most often arises post-trauma but may also occur iatrogenically or secondary to cubitus varus. The LUCL is the primary stabiliser against posterolateral rotatory stress; its failure leads to recurrent instability. Clinical tests such as the pivot-shift and chair push-up test aid diagnosis, while static imaging may miss dynamic instability. Surgical LUCL reconstruction with autograft or allograft demonstrates excellent outcomes, whereas conservative management is rarely effective. Importantly, uncorrected cubitus varus increases varus and rotational stress across the elbow, predisposing to recurrent instability after ligament reconstruction.
Conclusion: PLRI remains under-recognised and requires high clinical suspicion for diagnosis. Surgical LUCL reconstruction restores stability, but assessment of underlying cubitus varus is critical. Addressing coronal alignment may reduce recurrence risk and represents an underexplored avenue for improving outcomes.
