Greater medial meniscus extrusion seen on ultrasonography indicates the risk of MRI-detected complete medial meniscus posterior root tear in a Japanese population with knee pain

Abstract

To elucidate the association between medial meniscus extrusion measured on ultrasonography (MMEUS) and the prevalence of medial meniscus posterior root tear detected on magnetic resonance imaging (MMPRTMRI). We recruited 127 patients (135 knees; 90 females; mean age: 64.4 ± 8.7 years old; mean BMI: 25.5 ± 3.4 kg/m2) in this cross-sectional study. All participants had medial knee pain without a knee trauma or surgery history. Knee osteoarthritis (KOA) severity was evaluated using Kellgren-Lawrence grade (KLG) scores. Patients with KLG scores 0–1 and ≥ 2 were classified in non-radiographic (non-ROA) and radiographic KOA (ROA) groups, respectively. MMEUS was measured with patients in the supine position. Based on fat-suppressed T2-weighted images, MMPRTMRI was defined as the presence of “Ghost meniscus sign” and “Cleft/truncation sign”, indicating an abnormal high signal intensity of a completely disrupted posterior root. MMEUS was compared between MMPRT+ and MMPRT– patients using a non-paired t-test. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-off MMEUS to predict MMPRT+. The prevalence of MMPRT+ was 31.3% (25/80 knees) and 29.1% (16/55 knees) in the non-ROA and ROA groups. The MMEUS of MMPRT+ patients were significantly greater than that of MMPRT– patients in both the non-ROA (5.9 ± 1.4 mm vs. 4.4 ± 1.0 mm, P < 0.001) and ROA (7.8 ± 1.3 mm vs. 6.3 ± 1.3 mm, P < 0.001) groups. ROC curves demonstrated that 5-mm and 7-mm MMEUS were the optimal cut-off values in non-ROA (adjusted odds ratio: 6.280; area under the curve [AUC]: 0.809; P < 0.001) and ROA (adjusted odds ratio: 15.003; AUC: 0.797; P = 0.001) groups. In both early non-radiographic and established radiographic KOA stages, a greater MMEUS was associated with a higher MMPRTMRI prevalence.

Younger patients, lower BMI, complete meniscus root healing, lower HKA degree and shorter preoperative symptom duration were the independent risk factors correlated with the good correction of MME in patients with repaired MMPRTs

“…Pre‐operative weight‐bearing radiographs and standing anteroposterior radiograph were done to evaluate K‐L stages of knee osteoarthritis and hip–knee–ankle (HKA) angle. The MRI evaluation was done preoperatively and at the final follow‐up to assess correction of MME (mm) (MME was defined as meniscus displacement from the superomedial aspect of the tibial plateau to the periphery of the meniscal body, at the level of the medial collateral ligament [4]) and healing status of repaired MMPRTs, and the meniscal healing status was assessed according to the criteria of previous studies and was classified as complete healing (continuity in sagittal, coronal, and axial MRI views), partial healing (loss of continuity in any 1 view), none healing (no continuity and no evidence of meniscal healing at the repair site)[34].…”

Risk factors of incomplete healing following medial meniscus posterior root tear repair with gracilis tendon

“…The following parameters were recorded: demographic features, comorbidities, preoperative K-L stages knee osteoarthritis were evaluated on standing anteroposterior radiograph, hospitalization time, injury side, MMPRTs type 12 , preoperative varus degree on weight-bearing X-rays (preoperative long-leg standing radiographs were obtained from all the patients to assess hip–knee–ankle angle), preoperative medial meniscus extrusion (meniscus displacement from the superomedial aspect of the tibial plateau to the periphery of the meniscal body, at the level of the medial collateral ligament) 13 , preoperative and postoperative visual analogue scale (VAS), Lysholm score and international knee documentation committee (IKDC) score of the affected knee, complications, and radiological outcomes of the repaired MMPRTs at the final follow-up.…”

Medial Meniscus Posterior Root Tear: How Far Have We Come and What Remains?

“…Although medial meniscus extrusion is not a pathognomonic sign of MMRTs, parameters indicating the degree of extrusion and the amount of change can be used to predict these tears. On ultrasonographic evaluation, patients with MMRTs have greater medial meniscus extrusion than those without MMRTs [ 51 ]. Furthermore, dynamic medial meniscus extrusion, in accordance with changes in weight-bearing conditions, is reduced in patients with MMRTs [ 52 ].…”