Summary

Despite reconstructing ACL and repairing lateral meniscus, cartilage injury in the lateral tibial plateau worsened over time.

Abstract

Objective

Articular cartilage injuries are sometimes associated with acute anterior cruciate ligament (ACL) injuries, reported in 11-23% of cases. This rate increases to over 50% as injuries become more chronic. Untreated cartilage injuries can potentially lead to early knee osteoarthritis (OA) at a young age if untreated. ACL injuries often occur with meniscus injuries, which are usually treated simultaneously, however, cartilage injuries are often left untreated. Previous studies have reported on the natural history of cartilage injuries, but not on the arthroscopic evaluation of their extent and time-course changes. This study aimed to evaluate cartilage injuries in the lateral compartment associated with ACL and lateral meniscus (LM) injuries and investigate their progression after ACL reconstruction (ACLR) and LM repair.

Methods

Patients with radial/flap or longitudinal tears of the LM repaired with ACLR were retrospectively reviewed. Patients with a follow-up period of over 2 years and second-look arthroscopy were included. Exclusion criteria included medial meniscus tears, stable LM tears, meniscectomized LM, and complex LM tears. Patients were categorized into three groups: radial/flap tears (group R), longitudinal tears (group L), and controls without LM injuries (group C). Clinical assessments included pain, range of motion, swelling, Lachman test, and KT-1000 arthrometer measurements for anterior laxity. Radiographic evaluation included joint space width and osteophyte formation. Bone bruise was evaluated on preoperative magnetic resonance imaging (MRI). Second-look arthroscopy evaluated cartilage status using the International Cartilage Repair Society (ICRS) grading system.

Results

Ninety-two patients were analyzed: 34 in Group R, 28 in Group L, and 30 in Group C. There were no significant differences in demographics (age, sex and BMI) among the groups, except for time from injury to surgery. All patients achieved anterior stability with ACLR. Preoperative MRI showed bone bruise in the lateral femoral condyle and tibial plateau in over 68% of cases, with no significant difference among the groups. Radiographs showed no significant difference in joint space narrowing, but much more osteophyte formation in Group R and L. Second-look arthroscopy revealed worsened cartilage status in the lateral tibial plateau in Group R, with a significant difference compared to Group C, indicating potential degeneration despite meniscus repair.

Discussion

The study found that despite reconstructing ACL and repairing meniscus, cartilage injury in the lateral tibial plateau worsened over time, especially in patients with radial/flap tears. This suggests that the initial impact causing the ACL and meniscus injury also significantly affected the cartilage, leading to progressive degeneration. The study also highlighted the limitations of current meniscus repair techniques, which may not fully restore meniscal function. The findings raise concerns about the long-term risk of osteoarthritis and emphasize the need for more effective treatment strategies for cartilage injuries associated with ACL and meniscus injuries. Future research should focus on developing simplified cartilage repair techniques and long-term outcomes to prevent degenerative changes.