Anterior cruciate ligament tear and associated ligamentous and meniscal injuries - A magnetic resonance imaging-based study in a tertiary care centre in South Kerala

Introduction: The knee joint, being the largest synovial joint in the body, is highly susceptible to musculoskeletal pain and injury, frequently resulting in instability and range-of-motion limitations. The anterior cruciate ligament (ACL) is a crucial stabilizer, preventing the anterior translation of the tibia on the femur, and is commonly injured in athletes and trauma patients. Injuries to the ACL are often immediately disabling, require prolonged rehabilitation, and are frequently associated with trauma to the menisci (MM and LM) and other ligamentous structures. Magnetic Resonance (MR) imaging is the investigation of choice for assessing the status of the ACL and associated structures, as it helps identify subtle meniscal and ligamentous changes necessary for appropriate early management.

Aim: The aim of this study was to identify the association of ACL tear with ligamentous and meniscal injuries of the knee joint based on magnetic resonance imaging findings in a tertiary care centre in South Kerala.

Materials and methods: This was a cross-sectional study conducted in the Department of Radio diagnosis at a tertiary care centre in South Kerala from February 2020 to October 2021. The study population consisted of 79 patients, aged 18 to 40 years, of both genders, referred for MR imaging due to clinical suspicion of an ACL tear. Patients with contraindications for MRI, prior knee surgery, or infective arthritis were excluded. Data was collected using consecutive sampling, and radiological findings were studied from images obtained via a 1.5 Tesla MRI equipment. Statistical analysis involved presenting categorical data as frequency and percentages, continuous data using descriptive statistics (including mean and standard deviation), and associated injury frequencies with percentages and 95% confidence intervals.

Results: The study included 79 participants, 64.6% of whom were male, with a mean age of 28.75 ± 7.12 years. Partial ACL tears were found in 59.5% of cases, while complete tears accounted for 40.5%. Associated medial meniscal (MM) tears were observed in 68.4% of the participants. The most frequent MM injury patterns were posterior horn tear (30.4%) and posterior horn tear with body tear (22.8%). Lateral meniscal (LM) tears were found in 36.7% of the study population, with posterior horn tear being the most common specific pattern (11.4%). Regarding collateral ligaments, 21.6% had a medial collateral ligament (MCL) tear (20.3% partial), 7.6% had a lateral collateral ligament (LCL) tear, and 6.3% had a partial posterior cruciate ligament (PCL) tear. Meniscal injuries were notably more common than collateral ligament injuries.

Conclusion: A significant association was found between ACL tears and other concurrent ligamentous and meniscal injuries, with meniscal tears occurring much more frequently than collateral ligament injuries. Given the high prevalence of associated injuries (particularly MM tears), a comprehensive clinical and radiological assessment using MRI is crucial for practitioners to enhance prognosis and prevent overlooked injuries that may lead to delayed recovery or re-surgery.