POPLITEOMENISCAL FASCICULI AND LATERAL MENISCAL STABILITY

In an attempt to understand better the contribution of the anteroinfer ior and posterosuperior popliteomeniscal fasciculi to lateral meniscus stability, we objectively evaluated the stability of the lateral meni scus before and after sequentially sectioning these fasciculi. In the biomechanical model, we attempted to account for the inherent limitati ons of arthroscopic evaluation of lateral meniscal stability. When the fasciculi were intact, the average lateral meniscal motion with a 10- N load was 3.6 mm. When the anteroinferior fascicle was disrupted, the average lateral meniscal motion with a 10-N load was 5.4 mm. The mean increase in motion from the intact state was 1.8 mm or 50%, which was significant. When both fasciculi were disrupted, the average lateral meniscal motion with 10-N load was 6.4 mm, The mean increase in motion from the intact state was 2.8 mm or 78% and from the single fascicle disruption state was 1.0 mm or 18%, both differences were significant, The meniscus did not become locked With any of these loading trials, and it spontaneously reduced to the original position when unloaded, B oth fasciculi make significant contributions to meniscal stability, Ev en though the meniscus never became locked in the joint when loaded du ring this study, with the variable loads seen with normal activities m echanical symptoms might be expected when meniscal motion is almost do uble. An increase in lateral meniscal motion at the time of surgery ma y aid in the diagnosis of fasciculi disruption, despite normal menisca l structure on magnetic resonance images and at arthroscopic visualiza tion.