MRI has limited accuracy in diagnosis of knee injuries limited to Posterolateral corner and meniscus
A recent study published in The American Journal of Sports Medicine has demonstrated the accuracy of MRI for the diagnosis of multiple ligament knee injuries. Researchers reported the highest diagnostic accuracy of 94.4 % with injuries of the anterior cruciate ligament (ACL) and the lowest diagnostic accuracy of 76.2 % with injuries of the popliteus tendon.
It is already known that Magnetic resonance imaging (MRI) has limited diagnostic accuracy for multiple ligament knee injuries (MLKIs), especially posterolateral corner (PLC) injuries. In the present study, researchers developed a hypothesis that the diagnostic accuracy of MRI for MLKIs will only be moderate for some knee structures. Patient-related factors and injury patterns could modify this.
Researchers recorded findings related to sex, age, mechanism of injury, time from injury to MRI, and vascular and neurological-associated lesions. They also collected (MPI reports and surgical records) Lesions to the ACL, PCL, medial collateral ligament, lateral collateral ligament (LCL), popliteus tendon, popliteofibular ligament, iliotibial band, biceps tendon, medial and lateral meniscus, and articular cartilage.
The study results are:
- A total of 178 patients with a mean age of 33 years were included.
- The common causes or mechanisms of injury were High-energy trauma, sports trauma and low-energy trauma, constituting 50.6%, 38.8 % and 8.4 %, respectively.
- ACL had the best diagnostic accuracy, diagnostic odds ratio, and positive predictive value.
- The worst diagnostic accuracy was reported with PLC structures.
- The reliability of MRI was more in detecting the absence of meniscal and chondral lesions than in identifying them.
- The diagnostic accuracy was affected by the Schenck classification.
The diagnostic accuracy of MRI varies for MLKIs. This may become a cause of misdiagnosis. The MLKI's severity lowered the diagnostic accuracy of MRI for peripheral structures.
They said that MRI is better at identifying the absence of meniscal lesions than the presence. The diagnostic accuracy of MRI is limited with more severe injuries.
It is crucial for clinicians to understand that MRI cannot provide imaging of all lesions of knee injuries. They said that Posterolateral corner and meniscus injuries can be missed on MRI.
Further reading:
Sanchez-Munoz E, Lozano Hernanz B, Zijl JAC, et al. Accuracy of Magnetic Resonance Imaging in the Diagnosis of Multiple Ligament Knee Injuries: A Multicenter Study of 178 Patients. The American Journal of Sports Medicine. 2023;51(2):429-436. doi:10.1177/03635465221145697
