Is it possible to use stress radiographs as a tool to diagnose medial meniscus posterior root tears?

Abstract

Aim:Medial meniscus posterior root tear (MMPRT) causes meniscal extrusion, loss of meniscus function, arthritic changes. Clinical history, physical examination and magnetic resonance imaging (MRI) findings are useful for the diagnosis of MMPRT. The aim of this study is to evaluate the utility of stress X-rays in the diagnosis of MMPRT.Methods:Twenty patients who had undergone high tibial osteotomy between March 2015 and May 2016 and whose preoperative bilateral varus and valgus stress x-rays (Telos device) along with weight bearing x-rays were available were included. These patients were grouped into two according to integrity of posterior roots of their medial menisci; there were ten patients both in the study and control groups. Lateral joint space width (LJW) on varus stress x-rays, medial joint space width (MJW) on valgus stress x-rays as well as LJW and MJW on weight bearing x-rays were measured bilaterally. Intragroup comparisons of joint space widths between index and opposite knees were performed. Differences of MJW and LJW between index and opposite knees were calculated. Differences of joint space widths between stress x-rays and weight bearing x-rays were also calculated. The changes in joint space widths between the two groups were compared. Statistical analyses were performed utilizing SPSS 18.0. Significance level was set at 0.05.Results:In MMPRT group, opening of LJ space of index knees under varus stress was greater than that of opposite knees (Index: (mean±SD) 10,27±1,17 mm, opposite: 8,61±1,37 mm; p<0,0001). In the control group the difference was not significant (Index: 9,29±2,55 mm, opposite: 9,68±1,44 mm; p=0,566). The difference in the opening of LJW (under varus stress) between index and opposite knees was significantly greater in the study group (p=0,013). The difference between LJW under weight-bearing and varus stress conditions was significantly greater in the study group. (Study: 3,64±0.217 mm, control:2,28±0,182 mm, p=0.018).Conclusions:The findings of this study showed that in patients who had MMPRTs, an increased opening in the LJW was observed under varus stress conditions. This may be relevant with the fact that when varus stress is applied, meniscal extrusion is increased in case of a MMPRT. Stress x-rays could be a useful tool in the diagnosis of MMPRTs. Further studies are needed to determine the sensitivity and specificity of this diagnostic tool.