Posteromedial knee friction syndrome
Dynamic imaging of the posteromedial corner (PMC) would be useful to identify position changes in the sartorius and gracilis during knee flexion and abnormal motion in the PMC and around the posteromedial femoral condyle (PMFC). These changes can lead to posteromedial knee friction syndrome. Evidence of focal soft tissue edema between the PMFC, sartorius and/or gracilis should raise the suspicion of a friction syndrome.
The PMC has five major components: the semimembranosus tendon and its expansions, the oblique popliteal ligament, the posterior oblique ligament, the posteromedial joint capsule, and the posterior horn of the medial meniscus. The semimembranosus is the main dynamic stabilizer of the PMC. The PMC is a dynamic system, and injury to any one structure is capable of disabling the functional cascade of the posteromedial capsule.
The authors used MRI to study the PMC. MRI is not the best option for dynamic imaging of the PMC. Other research has shown that MSK ultrasound is highly capable in dynamic imaging of the PMC. See the image below how to visiualize the PMC with MSK ultrasound based on the guidelines of the European Society of Musculoskeletal Radiology.
> From: Simeone et al., Skeletal Radiol 44 (2016) 557–563. All rights reserved to ISS 2014. Click here for the Pubmed summary.