Femorotibial Contact Mechanics and Meniscal Strain after Serial Meniscectomy

Abstract

To evaluate changes in femorotibial contact areas (CA) and pressures and meniscal strain after serial meniscectomies of the caudal pole of the medial meniscus. Ex vivo biomechanical study. Unpaired pelvic limbs from 8 adult dogs weighing 28-35 kg. All specimens underwent sequentially, a 30% radial width partial meniscectomy, a 75% radial width partial meniscectomy, and a segmental caudal pole hemi-meniscectomy. Digital pressure sensors were used to measure lateral and medial peak and mean contact pressures and areas before and after serial meniscectomies. Meniscal strain was measured under load in the intact meniscus and after 30% and 75% radial width meniscectomy. Repeated measures analysis of variance with a post hoc Bonferroni's test (P<.05) was used for statistical analysis. A 30% radial width meniscectomy had no significant effect on contact mechanics. A 75% radial width caused a 60.9% increase and hemi-meniscectomy an 87.4% increase in peak contact pressures compared with control. Medial CA decreased by 34.7% after 75% radial width meniscectomy and 47.2% after hemi-meniscectomy. A 30% radial width meniscectomy resulted in 38.5%, and a 75% radial width meniscectomy a 69.2%, decrease in medial meniscal strain compared with control, but these differences were not statistically significant. In this cadaveric model, smaller (30%) partial meniscectomies had minimal effect on the biomechanics of meniscal function, whereas larger partial (75%) and segmental meniscectomies resulted in significant changes in meniscal and femorotibial contact mechanics. This ex vivo data should be considered in clinical decision making for treatment of meniscal problems in dogs.