Abstract
Purpose
Injuries of the meniscal attachments can lead to meniscal extrusion. We hypothesized that the extent of lateral meniscal extrusion (LME) was associated with the severity of the lateral meniscus posterior root tear (LMPRT). This study aimed to evaluate the relationship between preoperative LME and arthroscopic findings of LMPRT in knees with anterior cruciate ligament (ACL) injury.
Methods
Thirty-four knees that had LMPRTs with concomitant ACL injuries on arthroscopy were evaluated. Patients were divided into two groups, partial and complete root tears, via arthroscopic findings at the time of ACL reconstruction. We retrospectively measured preoperative LMEs using magnetic resonance imaging (MRI). Statistical analysis was performed using the Mann-Whitney U-test and Chi-square test.
Results
Twenty-three knees had partial LMPRTs (type 1). Complete LMPRTs were observed in 11 knees (type 2, 2 knees; type 3, 2 knees; and type 4, 7 knees). In the partial LMPRT group, the average LME was 0.43±0.78 mm. In the complete LMPRT group, the average extrusion was 1.99±0.62 mm. A significant difference between these groups was observed in the preoperative LMEs (P<0.01). The receiver operating curve analysis identified an optimal cutoff point of 1.05 mm for the preoperative LME. This LME cutoff had a sensitivity of 100% and specificity of 85% for complete LMPRT.
Conclusion
This study demonstrated that preoperative LMEs were larger in complete LMPRTs associated with ACL injuries than in partial LMPRTs. Our results suggest that preoperative MRI-detected LME may be a useful indicator for estimating LMPRT severity in knees with ACL injury.
