Yoonah Song MD, Presenter: Nothing to Disclose

Seunghun Lee MD, Abstract Co-Author: Nothing to Disclose

Kyung-Bin Joo MD, Abstract Co-Author: Nothing to Disclose

Woo Kyoung Jeong MD, Abstract Co-Author: Nothing to Disclose

Jeong Ah Ryu MD, PhD, Abstract Co-Author: Nothing to Disclose

Soon-Young Song, Abstract Co-Author: Nothing to Disclose

The purposes of this study were to evaluate the incidence of impingement of posterior cruciate ligament (PCL) and to reveal the relationship between impingement of PCL and other injuries of ligaments on the knee magnetic resonance imaging (MRI).

From August 2010 to February 2011, a total of 199 consecutive patients who underwent knee MRI were enrolled. Twenty-six of patients with established fracture (n=25), bone tumors (n=1) were excluded from this study. Thus, a total of 173 patients (98 women, 75 men; mean age, 45.0 years; range, 3-88 years) were included in this study. Five of 173 patients (4 women, 1 man) underwent knee MRI bilaterally. All images were retrospectively assessed by two musculoskeletal radiologists in consensus. In all cases, assessment included evaluation of the presence of the impingement of PCL on coronal scans of knee MRI and the  tear of anterior cruciate ligament (ACL), PCL, medial and lateral menisci, medial collateral ligament (MCL), fibular collateral ligament (FCL), and popliteus tendon. An imaginary line was drawn from medial femoral condyle to lateral intercondylar tubercle of tibia in coronal proton-weighted images. When PCL crossed the imaginary line, impingement of PCL was considered to be positive. We also analysed the relationships between impingement of PCL and injuries of adjacent ligaments or menisci using chi-square test. P values less than 0.05 were regarded as statistically significant.  

Of 173 patients, 45 impingements of PCL (25.0%) were identified on coronal PD-weighted MRI, which was performed on a 10º flexed knee. PCL impingement was identified in three (6.7%) of 45 patients who had no evidence of injury. Forty-two (93.3%) of 45 patients had injuries of ligaments or menisci. No mention about the impingement of PCL in all surgical reports. The impingement of PCL showed statistically significant association with tear of PCL (p=0.012), and tear of popliteus tendon (p=0.016). However, injuries of ACL, MCL, FCL and medial and lateral menisci showed no statistical significancy.

The presence of the impingement of PCL on coronal MRI is thought to be a significant relationship with the tear of PCL or popliteus tendon. Therefore, this may be helpful for detecting of tear in the PCL or popliteus tendon on knee MRI.

If impingement of PCL is seen in coronal MRI of knee, the tear of PCL or popliteus tedon could be suggested.

Song, Y, Lee, S, Joo, K, Jeong, W, Ryu, J, Song, S, Impingement of Posterior Cruciate Ligament on Coronal Scans of Knee MRI: Is This a Secondary Sign of Tear or Normal Variant in the Posterior Cruciate Ligament?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015671.html