Purpose: To identify risk factors for posterior lateral meniscus root tears (PLRT) in patients with a tear of the anterior cruciate ligament (ACL).
Methods: A database of 268 patients undergoing primary ACL reconstruction between 2011 and 2013 was used to identify all patients with isolated ACL tears and patients with an associated PLRT. Patients with other concomitant injuries and patients who underwent surgery >6 months after the injury were excluded. Univariate analysis was performed by comparing the two groups with regard to gender, age, age groups (<30 vs. >30 years), height, weight, body mass index (BMI), BMI groups (<24.9, 25-29.9, and >30), type of injury (high-impact sports, low-impact sports, and not sports-related), and mechanism of injury (non-contact vs. contact). Multivariate logistic regression was carried out to identify independent risk factors for PLRT and to calculate odds ratios (ORs).
Results: One-hundred and forty-two patients met the inclusion and exclusion criteria. Of those, 120 (85%) had an isolated ACL tear and 22 (15%) had an associated PLRT. No significant differences between patients with and without a PLRT were found for age, age groups, height, weight, BMI, BMI groups, and type of injury (p > 0.05). Univariate analysis revealed a statistically significant difference between both groups for gender distribution (p = 0.034) and mechanism of injury (p < 0.001), with male gender and a contact mechanism being more common in patients with PLRT. The sole independent risk factor for an associated PLRT identified in the multivariate logistic regression analysis was a contact mechanism with an OR of 17.52.
Conclusion: An associated PLRT is more common in male patients and patients who sustained a contact injury. Patients with a contact injury mechanism have an approximately 17-fold increased risk for a PLRT compared to patients with a non-contact injury. Special attention for this injury pattern is therefore necessary in those patients, and early referral to magnetic resonance imaging or arthroscopy is recommended.
Level of evidence: IV.