Arthroscopic Treatment of Scapholunate Instability: A Stage- and Ligament-Based Narrative Review.

Scapholunate (SL) instability is the most common form of carpal instability, and if untreated, it may progress through dorsal intercalated segment instability to scapholunate advanced collapse. Contemporary understanding emphasizes a dual stabilizing system in which the SL interosseous ligament (SLIL) acts as the intrinsic primary restraint, reinforced by extrinsic "critical" secondary stabilizers; isolated SLIL division does not by itself produce static malalignment until these secondary restraints are also compromised. Against this background, wrist arthroscopy has become a widely used reference standard for diagnosis and grading, allowing for graded assessment through the Geissler and the more granular European Wrist Arthroscopy Society (EWAS) classifications, while dry arthroscopy has reduced fluid-related morbidity and facilitated combined arthroscopic and mini-open procedures. Treatment has correspondingly shifted from open reconstruction toward arthroscopic and arthroscopic-assisted repair, capsulodesis, and ligamentoplasty, which are intended to preserve native capsuloligamentous structures and may offer potential advantages in limiting capsular disruption and postoperative stiffness. This narrative review synthesizes the literature identified through a selective search of PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar (final search 13 June 2026). The evidence consists mainly of small observational series and technique reports. The review stages the injury by arthroscopic grade (EWAS/Geissler) and organizing techniques by the target ligament(s), from partial and dynamic injuries through complete, reducible, and advanced deformities. We align each technique with the corresponding pattern of intrinsic and extrinsic ligament injury to clarify indications, summarize reported outcomes, and propose a stage-based conceptual treatment framework rather than a validated, evidence-based guideline. Current evidence derives largely from small, heterogeneous case series with variable classifications and outcome measures, underscoring the need for standardized staging and comparative studies.