Complete posterolateral meniscal root tear is associated with high-grade pivot-shift phenomenon in noncontact anterior cruciate ligament injuries.

ABSTRACT

PURPOSE: The purpose of this study was to investigate whether the complete posterolateral meniscal root tear (PLMRT) would be associated with high-grade pivot-shift phenomenon in noncontact anterior cruciate ligament (ACL) injuries. METHODS: From 2013 to 2015, a total of 1095 consecutive patients were diagnosed as having noncontact ACL injuries and underwent primary ACL reconstructions. Among them, 140 patients were arthroscopically verified to have concomitant PLMRTs. Application of the exclusion criteria finally left 74 patients who were finally allocated into high-grade pivot-shift (grades II and III) group (n = 51) and low-grade pivot-shift (grades 0 and I) group (n = 23) according to the results of pre-operative pivot-shift tests performed under anesthesia. Predictors of high-grade pivot-shift phenomenon, including degree of PLMRTs, integrity of posterior MFLs, status of lateral meniscal extrusion, age, sex, body mass index (BMI), and KT-1000 arthrometer side-to-side difference (SSD), were assessed by multivariable logistic regression analysis. RESULTS: The proportion of patients with complete PLMRT in high-grade pivot-shift group was significantly larger than that in low-grade pivot-shift group. In addition, complete PLMRT was significantly [odds ratio (OR) 4.044; 95% CI 1.125-14.534; P = 0.032] associated with high-grade pivot-shift phenomenon in noncontact ACL injury, especially for those with a time from injury to surgery of ≥12 weeks (OR 16.593; 95% CI 1.073-56.695; P = 0.014). However, no significant association was identified between neither the integrity of posterior MFLs nor the status of lateral meniscal extrusion and the high-grade pivot-shift phenomenon. CONCLUSION: Complete PLMRT is identified to be an independent risk factor of high-grade pivot-shift phenomenon in noncontact ACL injuries, particularly for those with a time from injury to surgery of ≥12 weeks. LEVEL OF EVIDENCE IV.