Study of Imaging Pattern in Bone Marrow Oedema in MRI in Recent Knee Injuries and its Correlation with Type of Knee Injury

A posterior shiny-corner lesion of the tibia is observed in the early phase after medial meniscus posterior root tear

BACKGROUNDS

Medial meniscus (MM) posterior root tear (PRT) results in joint overloading and degenerative changes in the knee, and pullout repair is recommended to prevent subsequent osteoarthritis. Diagnosing MMPRT is sometimes difficult, especially in the case of an incomplete tear. A posterior shiny-corner lesion (PSCL) is reported to be useful for diagnosis, although the association between MMPRT and PSCL is unknown. This study aimed to investigate the properties of PSCL, such as the location, volume, and duration from injury to the time of MRI (duration). We hypothesized that PSCL is observed in the early phase after the MMPRT onset.

METHODS

T2-weighted fat-suppression magnetic resonance imaging (MRI) was obtained from 55 patients with MMPRT preoperatively. The prevalence of the PSCL; giraffe neck, cleft, and ghost signs; severe MM extrusion (> 3 mm); and the PSCL volume were evaluated. The PSCL lesion elliptical volume (mm³) was calculated by measuring the anteroposterior, transverse, and craniocaudal dimensions.

RESULTS

PSCL was observed in 34 (62%) cases. The mean volume of the PSCL was 102.0 mm³. A significantly shorter duration was observed in the PSCL-positive group (5.6 weeks) than that in the PSCL-negative group (40.9 weeks, P < 0.01), although no significant correlation was observed between the PSCL volume and duration. The sensitivity for the MMPRT was 90.5% when the cut-off duration value was 3 weeks and 81.8% when the cut-off value was 8 weeks.

CONCLUSIONS

MRI examination may detect PSCL if it is performed early following MMPRT onset. Detecting PSCL may be useful in diagnosing MMPRT with high sensitivity.

High Prevalence of Anterolateral Ligament Abnormalities on MRI in Knees With Acute Anterior Cruciate Ligament Injuries: A Case-Control Series From the SANTI Study Group

Background:

Broad variation in the reported rate of magnetic resonance imaging (MRI)–detected abnormalities of the anterolateral structures of the anterior cruciate ligament (ACL)–injured knee suggests a lack of reliability that has limited the use of MRI in clinical decision making.

Purpose/Hypothesis:

The aim of this study was to use MRI to determine the prevalence and spectrum of abnormalities of the anterolateral structures in acute ACL-injured knees, using the contralateral uninjured knee as a reference. We hypothesized that MRI evaluation of the acutely injured knee (using the uninjured knee as a reference) would allow reliable identification of abnormalities of the anterolateral structures.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

Patients with acute ACL injury underwent MRI scan of both knees. Images were evaluated by 3 observers. Inter- and intraobserver reliabilities were determined for MRI parameters of anterolateral ligament (ALL) injury by use of the kappa (κ) test. Univariate and multivariate analyses were conducted to test associations between ALL abnormality and associated injuries.

Results:

A total of 34 patients were evaluated. Of these, 30 patients (88.2%) had at least 1 ALL abnormality in the ACL-injured knee (increased signal: n = 27[79.4%]; increased thickness: n = 15[44.1%]; tapering: n = 7[20.6%]; irregularities in the path of the ALL fibers: n = 21[61.7%]). Asymmetries of the genicular vessels were observed in 21 patients (61.7%). ALL abnormality was significantly associated with lateral joint capsular tears (P < .001). No correlation was found between ALL lesions and iliotibial band lesions (P = .49). Inter- and intraobserver reliabilities were very good concerning ALL signal changes and femoral and tibial bone bruises (κ coefficient, 0.81-1).

Conclusion:

MRI evaluation of the ALL was associated with good and very good inter- and intraobserver reliabilities, and it demonstrated abnormalities of the ALL in the majority of acutely ACL-injured knees. The index of suspicion for ALL injury should be elevated by the presence of lesions of the lateral capsule. This suggests that the ALL is part of a wider area of the lateral capsule that is often injured simultaneously in an acute ACL tear.