Summary
Meniscus tears occur with notable frequency in adolescents with patellofemoral instability, therefore surgeons must perform a diligent diagnostic arthroscopy at the time of surgery to avoid undiagnosed meniscus pathology.
Abstract
Introduction
Patellofemoral instability (PFI) is one of the most common knee conditions within the adolescent population. While associated meniscus pathology has been reported in other knee injuries, there is paucity in the literature regarding the presence of meniscus injuries in patients with patellofemoral instability. The purpose of this study is to determine the incidence and characteristics of meniscus tears in adolescent patients with PFI.
Methods
This retrospective study identified patients with recurrent patellofemoral instability that underwent medial patellofemoral ligament (MPFL) reconstruction and were 18 years of age or under at the time of surgery. The primary outcome was the presence of a meniscus tear during the diagnostic arthroscopy. Additional outcome data included the location, pattern, and treatment of each meniscus tear, as well as post operative outcome data. A subgroup analysis was performed, which separated patients into acute (fewer than 12 weeks from initial injury to surgery) and delayed (greater than 12 weeks from initial injury to surgery) groups in an effort to determine when these meniscus tears occurred.
Results
The incidence of meniscus tears was 22 out of 74 knees (29.7%). Of these tears, an isolated lateral meniscus tear was present in 12 knees (54.5%), and isolated medial meniscus tear was present in 8 knees (36.4%), p=0.3711. Tears of both medial and lateral menisci occurred in 2 knees (9.1%). The tears occurred most frequently in the periphery of the meniscus (20, 83.3%) compared with the white-white region (4, 16.7%), p=0.0011, and were most commonly found at the posterior/body junction (15, 62.5%), as compared with the body (6, 25%), posterior horn (2, 8.3%), and anterior horn (1, 4.2%), p=0.0001. The most frequent pattern of tear was meniscocapsular separation (18, 75%), compared with radial (4, 16.7%), oblique (1, 4.2%), and complex (1, 4.2%) tears, p=0.0001. The subgroup analysis (24 acute, 50 chronic) determined no statistical significance in the frequency of meniscus pathology in the acute (10, 41.7%), as compared to the chronic group (13, 26%), p=0.1739.
Conclusion
Meniscus tears occur with notable frequency in adolescents with PFI, with pathology most frequently seen as meniscocapsular separation located in the posterior/body junction of both the lateral and medial menisci. Therefore, surgeons must perform a diligent diagnostic arthroscopy at the time of MPFL reconstruction to avoid undiagnosed meniscus pathology. Further, increased time from injury to MPFL reconstruction was not found to be associated with increased rates of meniscal pathology, indicating that these meniscal tears likely occur at the time of initial MPFL injury, rather than being attributable to increased post-injury instability.