Anatomic and Histologic Analyses of the Popliteal Hiatus Area of the Lateral Meniscus Reveal the Meniscofibular Ligament and the Posteroinferior Popliteomeniscal Fascicle Are Ligamentous Tissue.

Abstract

To characterize the anatomical structure and histological composition of connective tissue around the popliteal hiatus of the lateral meniscus (LM): the posterosuperior popliteomeniscal fascicle (PS-PMF), posteroinferior popliteomeniscal fascicle (PI-PMF), and anterior popliteomeniscal fascicle (A-PMF), meniscofibular ligament (MFL), and popliteofibular ligament (PFL). Six fresh-frozen cadaveric knees from unpaired donors with intact anatomy, no history of surgical intervention, and no gross pathological alterations were labeled and dissected, including 3 male and female donors, with a mean age of 53 years (range: 39-68 years). The PS-PMF, PI-PMF, A-PMF, MFL, and PFL were examined anatomically, and histological analysis was performed. The PS-PMF originated from the posterior aspect of the popliteus tendon (PT), crossing its posterior border (n = 5/6) or originating from the superior aspect (n = 1/6), and inserted onto the LM superiorly. The PI-PMF originated from the anterior border of the PT (n = 5/6) or its superior aspect (n = 1/6) and inserted onto the LM inferiorly. Adipose tissue consistently separated the PS-PMF and the PI-PMF. An interfascicular interval between the MFL and PI-PMF was observed (n = 5/6). The MFL originated from the LM, connected superiorly to the A-PMF, and converged inferiorly with the PFL. Histologically, the MFL and PI-PMF exhibited ligamentous characteristic, and the A-PMF and the PS-PMF had a vascular synovial structure. The PS-PMF, PI-PMF, A-PMF, MFL, and PFL are distinct anatomical components. The PS-PMF and the PI-PMF form a combined encapsulation around the PT. The MFL and PI-PMF are ligamentous. Given the limited intrinsic healing capacity of MFL injuries, surgical repair combined with trephination of the PT or microfracture is recommended. This study enhances understanding of lesions in the connective tissue around the popliteal hiatus area, supporting more anatomically precise and biologically informed interventions.