Value and imaging findings of the magnetic resonance in the posterolateral corner complex injuries of the knee

Background MRI is considered the key tool for evaluation of knee injuries, notably the posterolateral corner, due to its complexity and multi-ligament involvement. This prospective study was conducted from September 2020 to September 2021 aiming to clarify the value and possible MRI findings in assessing the posterolateral corner (PLC) knee injuries which can subsequently result in an improvement in the management of these cases, preventing devastating consequences. Results The current study was conducted on 30 patients (11 females and 19 males) whose mean age was 42 years. Imaging by a closed magnet (1.5 T) MRI was applied to 30 patients with traumatic history to the knee using: axial, sagittal, coronal T1WI, T2WI, and proton density fat sat sequences. The lateral collateral ligament (LCL) was the most commonly affected ligament. Grade I injuries were the most common form of injuries. Twenty-four (80%) patients suffered from LCL injury, popliteal complex injuries were in 21 (70%) patients, 10 (33.3%) patients had biceps femoris tendon injury, while injury to the popliteofibular ligament was seen in 8 (26%) patients. The arcuate ligament was poorly defined in 6 (20%) patients, indicating that it had torn, lateral head of gastrocnemius injury was seen in 5 (16.7%) patients and 4 (13.3%) patients showed injury to the iliotibial band. Correlation with arthroscopic findings was considered the gold standard of the results whenever available. That was applied to 16 cases who had clinically significant knee injuries and arthroscopy was requested. Conclusions MRI is a key tool for determining a correct pre-surgical evaluation and diagnosis. It is critical to have a thorough understanding of the radiological PLC anatomy, as well as the presence of various pathologies on MRI. It allows the determination of whether the tendons and ligaments are partially or completely torn, besides any related injuries preventing possible poor consequences after the restoration of the cruciate ligaments.