Introduction

Anterior Cruciate Ligament (ACL) injury in the pediatric population has increased during the last decades. Correct treatment of the associated lesions, together with the ligament reconstruction, is crucial for good clinical outcomes and prevention of joint degeneration. The purpose of this study is to describe the characteristics of meniscus tears associated with ACL injury, identify which variables are related to their presence and evaluate the rate of postoperative reinjury and complications.

Methods

All patients under age 17 year who underwent ACL reconstruction between 2000 and 2018 at a single institution were reviewed at minimum 2-year follow-up. Meniscus tear characteristics and treatment, anthropometrics measurements, grade of skeletal maturity (open, closing, or closed femoral and tibial physis at X-ray), ACL reconstruction surgical technique, and postoperative reinjury and complications were recorded. Multivariate logistic regression was used to evaluate which factors were associated with primary meniscal lesions; Kaplan-Meier analysis was performed to determine the rate of meniscal survival after treatment. 6 patients who underwent Physeal Sparing ACL reconstruction were excluded from the analysis.

Results

Of 272 ACL reconstructions (171 females, 101 males, mean age of 15.4 ± 1.3), the overall rate of meniscus injury was 66.5%, lesions were more frequently lateral (79.6%), and in general 23.3% of them were bilateral. The posterior horn was most involved (71.5% of lateral tears, 91.1% of medial tears), and a vertical longitudinal was the most frequent type (25.8% of lateral and 48.1% of medial tears). The multivariate logistic regression analysis highlighted that patients with lower chronological age at primary ACL surgery (P=0.047) and contact injury (P=0.027) were associated with higher risk for a meniscus tear. The lateral lesions were most frequently repaired (44.7%), followed by partial meniscectomy (23.7%), similarly medial lesions underwent mainly repair (59.5%), and partial meniscectomy (12.6%). Non-operative treatment was opted for 20.3% of lateral and 22.7% of medial tears. Overall, the rate of second meniscal injury after primary ACL reconstruction was 3.4% at 10 years and 8.0% at 20 years after surgery. The use of hamstring graft for primary ACL reconstruction was associated to higher risk (P=0.040), no differences were found for sex, grade of skeletal maturity. 58.7% of all the secondary meniscus tears were concomitant with an ACL reinjury. Considering only the patients with a primary meniscal lesion, the meniscus reinjury rate was 12.5% and 1.9% at 10 years, 41.7% and 4.0% at 20 years in the ACL reinjury and no ACL reinjury groups respectfully. Analyzing patients without ACL reinjury, even if not statistically different, open physis is associated with lower risk of secondary meniscus tear (P=0.779).

Conclusion

Meniscus tear at the time of primary ACL injury is common in patients under age 17. Younger patients and contact injuries are associated to higher risk. Most meniscal tears can be repaired. Restoration of knee stability to prevent secondary ACL injury is the most important factor to avoid additional meniscus tears.