Meniscal-Related Risk Factors for Lateral Meniscal Extrusion: A Narrative Review
摘要
Meniscal extrusion is an important imaging marker of meniscal dysfunction and altered knee joint biomechanics. While medial meniscal extrusion has been extensively investigated, lateral meniscal extrusion remains comparatively underexplored despite its clinical relevance, particularly in younger and athletic populations.
ObjectiveTo provide a narrative review of meniscal-related risk factors associated with lateral meniscal extrusion.
MethodsA narrative literature review was performed using the PubMed database to identify studies published between January 2000 and December 2025, supplemented by additional relevant sources. Relevant peer-reviewed studies addressing meniscal-related contributors to lateral meniscal extrusion were identified. Risk factors were categorized into meniscal shape and morphology, meniscal pathology and meniscal surgical interventions.
ResultsMorphological variations, including discoid lateral meniscus, increased meniscus-bone angle and greater meniscal cartilage height, predispose individuals to lateral meniscal extrusion. Specific meniscal pathologies, such as posterior root tears, radial tears, complex tears and degenerative tear patterns, disrupt circumferential hoop stress and significantly increase the risk of extrusion. Lateral meniscal extrusion is also frequently observed following surgical interventions, particularly partial meniscectomy, discoid meniscus reshaping procedures and meniscal allograft transplantation. Post-operative extrusion has been associated with poorer clinical outcomes, increased cartilage degeneration and technical factors related to surgical technique and graft positioning.
ConclusionLateral meniscal extrusion is primarily driven by structural instability rather than degenerative change. Discoid morphology, unfavorable meniscal geometry, complex tear patterns and prior meniscal surgery are major contributing factors, underscoring the clinical importance of meniscal preservation.