Effect of Medialized Versus Anatomic Repair of Medial Meniscus Posterior Root Tears on Joint Contact Mechanics: A Cadaveric Model of Simulated Gait.
Academic Article
Overview
abstract
BACKGROUND: The biomechanical consequences of the repair of medial meniscus posterior root (MMPR) tear-whether anatomic or nonanatomic-during simulated gait have not been quantified. HYPOTHESIS: Medialized root repair would result in increased peak contact stress and proportion of compartment load acting through the meniscus and decreased contact area compared with anatomic root repair throughout simulated gait. STUDY DESIGN: Controlled laboratory study. METHODS: Six human cadaveric knees were mounted on a robotic test system programmed to apply dynamic forces, moments, and flexion angles to mimic level walking. Contact area, peak contact stress, and proportion of compartment force acting through the meniscus were measured throughout the stance phase of the simulated gait cycles for the following nonrandomized conditions: (1) native meniscus-"intact" condition, (2) root repair at the anatomic location, and (3) root repair 10 mm medially. The difference between the anatomic and medialized repair conditions was calculated for each metric, and then the mean and 95% CI were computed. RESULTS: No difference was found in contact area, peak contact stress, or proportion of compartment force through the meniscus between the medialized and anatomic repair conditions. During the early stance phase of simulated gait (10%-22% of gait cycle), medialized repair of MMPR tear resulted in significant decrease in contact area of 54 mm2 compared with anatomic repair. This change is on average 15% of the magnitude of change in area as previously quantified to occur with medial meniscectomy and as such is deemed a small and a potentially clinically insignificant change. CONCLUSION: Medialized repair of MMPR tear led to a small decrease in contact area compared with an anatomic repair during the early stance phase of simulated gait, with no difference in peak contact stress or proportional force through the meniscus throughout the simulated gait cycle. CLINICAL SIGNIFICANCE: This study provides unique data about the mechanical effects of anatomic and medialized root repair throughout simulated gait in a cadaveric model. With minimal changes between the 2 repair states, even at peak compressive and anterior load, there is mechanical justification that a medialized root repair may be an appropriate intervention if an anatomic repair is not possible.
