Analysis of the Mechanical Axis of the Lower Limb in Patients with Isolated Meniscal Tear

ABSTRACT

PURPOSE: We wanted to evaluate the relationship between meniscal tear and the alignment of the lower limb. MATERIALS AND METHODS: Between Oct 2006 and Jun 2008, 125 patients aged 55 year or less with isolated meniscal tear and who were examined arthroscopically were included in this study. The patients had no severe lesion (ulceration or defect) of cartilage or ligamentous injuries. 21 individuals who had no abnormal findings on MRI were selected as the control group. The patients were divided into the complete discoid lateral meniscus, incomplete discoid lateral meniscus, lateral semilunar meniscus and medial semilunar meniscus groups and they were subdivided according to gender and whether there was an obvious history of trauma. The varus percentage was defined as a percentage of the width from where the mechanical axis passes the level of the tibial articular surface to the middle of the tibial articular surface on the orthoroentgenogram of the lower leg. Each individual's varus percentage was expressed as the mean of the measurements taken by three observers. The comparisons were done using the Wilcox Signed Ranks Test and the Mann-Whitney Test. RESULTS: There was no significant difference between the involved knee and the contralateral normal knee in terms of the varus percentage in all the groups (p>0.05). There were no significant differences in each group according to the history of trauma, a complete discoid lateral meniscus, an incomplete discoid lateral meniscus, a lateral semilunar meniscus and a medial semilunar meniscus. However, there was a significantly greater varus percentage for the medial semilunar meniscus group without a history of trauma. CONCLUSION: There was a statistical relationship between tears on the medial semilunar meniscus without a history of trauma and genu varum. Tears on a complete discoid lateral meniscus, incomplete discoid lateral meniscus and lateral semilunar meniscus had a little relationship with the mechanical axis of the lower leg.