Background

The medial and lateral menisci function to optimize force transmission across the knee by increasing contact area between the femur and tibia, absorbing shock, and transmitting loads. The anterior and posterior meniscus roots anchor the meniscus to bone. Injuries to the meniscus root attachments result in extrusion of the meniscus, impaired distribution of hoop stresses, and progressive degenerative articular wear. As a result of these deleterious effects, there has been increasing emphasis on repair of meniscus root injuries to restore structure and function.

Purpose

The purpose of this study is to describe meniscus root tears, associated injuries, and minimum 2-year treatment outcomes in a series of pediatric patients

Study Design: Case series

Methods

A single-institution, IRB approved, retrospective review was performed of consecutive pediatric patients less than 19 years of age with a meniscus root tear treated with transosseous root repair over a 4-year period. All patients had minimum 24-month clinical follow-up. Partial root tears treated with partial meniscectomy or irreparable root tears were excluded. All meniscus root tears were classified arthroscopically based on the tear types described by LaPrade9. The primary outcomes were revision meniscus surgery and patient reported outcome scores (PROs) (Lysholm, Patient Satisfaction, and Tegner activity).

Results

Twenty-one patients, 11 males and 10 females with a mean age of 15 years (range 7 – 18 years), met inclusion critiera. There were 15 lateral meniscus root tears and 6 medial meniscus root tears. The tears occurred in the posterior root in 20 patients (95%). The most common injury pattern was a lateral meniscus posterior root tear (14 patients, 67%). 18 patients (86%) had an associated ligament tear: 13 ACL tears and 5 PCL tears. Two root tears occurred in isolation, and both were the posterior root of the medial meniscus. The majority of meniscus root tears (15 patients, 71%) were root avulsions (type 5).

Mean follow-up was 42 months (range 25 – 71 months). Three patients had a second surgery on the affected knee. In two patients, one with revision ACL reconstruction and one treated with chondroplasty of the patella, the meniscus root repair was noted to be well healed. A third patient sustained a new injury to the knee 4 years following medial meniscus posterior root repair and underwent partial medial meniscectomy. At final follow-up, PROs were obtained for 17 patients (81%). Mean Lysholm score was 91 (range 51 – 100). Mean patient satisfaction score was 8.7 (range 5 – 10). Fourteen of 16 patients (88%) reported returning to the same or higher level of activity following surgery.

Conclusions

Meniscus root tears occur in pediatric patients, most commonly as root avulsions of the posterior root of the lateral meniscus and in association with ACL tears. This is unique as compared to the adult population, in which the medial meniscus posterior root is often injured in isolation and radial tears adjacent the root are the most commonly described injury pattern. In our case series, transosseous root repair resulted in successful outcomes in the majority of patients with durable results at midterm follow-up.