2025 ISAKOS Biennial Congress ePoster
Unveiling the Low Incidence of 'Isolated' Anterior Cruciate Ligament Injury: Highlighting the Overlooked Anterolateral Complex and Medial Collateral Ligament Complex injuries
Hiroaki Fukushima, MD, PhD, Nagoya, Aichi JAPAN
Masahiro Nozaki, MD, PhD, Nagoya, Aichi JAPAN
Shunta Hanaki, MD, Nagoya, Aichi JAPAN
Kensaku Abe, MD, PhD JAPAN
Kyohei Ota, MD, Nagoya, Aichi JAPAN
Makoto Kobayashi, MD, PhD, Nagoya, Aichi JAPAN
Yusuke Kawanishi, Nagoya, Aichi JAPAN
Jiro Kato, Nagoya, Aichi JAPAN
Sho Yamauchi, MD, Nagoya JAPAN
Tetsuya Takenaga, MD, PhD, Nagoya, Aichi JAPAN
Masahito Yoshida, MD, PhD, Nagoya, Aichi JAPAN
Hideki Murakami, MD, PhD, Nagoya JAPAN
Nagoya City University Graduate School of Medicine, Nagoya, Aichi, JAPAN
FDA Status Cleared
Summary
This study reveals that truly isolated ACL injuries are rare (13% of cases), with most accompanied by concomitant meniscal and soft tissue injuries, particularly to the anterolateral complex (ALC) and medial collateral ligament complex (MCLC), and demonstrates that ramp lesions and ALC injuries significantly contribute to knee instability, emphasizing the need for comprehensive diagnostic approach
ePosters will be available shortly before Congress
Abstract
Background
The importance of diagnosing and treating concomitant injuries in anterior cruciate ligament (ACL) injury has been widely discussed, particularly meniscal ramp lesions (RL), lateral meniscus posterior root tears (LMPRT), and soft tissue injuries involving the anterolateral complex (ALC) and medial collateral ligament complex (MCLC). This study aimed to investigate the incidence of these injuries in clinically 'isolated' ACL injuries and examine their impact on knee instability.
Methods
Patients who underwent ACL reconstruction between June 2016 and June 2024 were retrospectively included. Exclusion criteria were revision ACL surgery, osteoarthritis, duration between injury and surgery exceeding 6 months, concomitant other ligament reconstruction, symptomatic MCL injury, and Segond fracture. Preoperative MRI performed within 3 weeks of injury was evaluated to diagnose ALC and MCLC injuries. Patient demographics and meniscal injuries diagnosed during ACL reconstruction were retrieved from medical records. The study examined the prevalence of ALC and MCLC injuries, as well as the proportion of truly isolated ACL injuries in the patient cohort. Anterior tibial translation (ATT) and pivot shift grade were assessed to evaluate knee instability. Regression analyses were performed to determine the contribution of RLs, LMPRT, ALC injuries, and MCLC injuries to knee instability. The significance was set at 0.05.
Results
Of 521 ACL reconstruction patients, 110 patients met inclusion criteria. 66 patients had concomitant injuries, including 48 medial (36 RLs) or 38 lateral (14 LMPRT) meniscal injuries. Of the remaining 44 patients initially diagnosed with 'isolated' ACL injury, 30 showed either ALC or MCLC injury on MRI. Only 14 patients (13%) had truly isolated ACL injuries without any concomitant injuries. Among the 110 patients evaluated by MRI, 71 (65%) had ALC injuries and 66 (60%) had MCLC injuries. While no factors significantly affected ATT, RLs showed a weak influence (coefficient 0.6, p=0.062). Regarding pivot shift grade, both RLs (coefficient 1.1, p=0.0085) and ALC injuries (coefficient 0.9, p=0.022) were found to be significant contributing factors.
Discussion
Our findings demonstrate the rarity of isolated ACL injuries and highlight the need for comprehensive evaluations. The high incidence of ALC and MCLC injuries suggests that these structures should be carefully considered during surgical planning. The significant contribution of ramp lesions and ALC injuries to knee instability indicates that addressing these specific lesions is crucial for effective restoration of knee stability and improving patient outcomes. The lack of significant findings related to MCLC injuries may be due to limitations in current diagnostic tools, such as the ATT and pivot shift tests, which may not fully capture the instability patterns associated with these injuries. Further research is needed to refine diagnostic techniques and better understand the role of MCLC injuries in ACL instability.
Conclusion
Most ACL injuries are accompanied by concomitant meniscal and soft tissue injuries, rather than being truly isolated. These findings underscore the need for a comprehensive diagnostic approach in ACL injury cases to accurately identify and address associated lesions. Specifically, the effective management of RLs and ALC injuries may be crucial for restoring knee stability and improving long-term patient outcomes.