Dynamic ultrasound assessment of lateral meniscal instability associated with popliteomeniscal fascicle disruption: A prospective observational study.

Abstract

No established imaging method is currently available for detecting popliteomeniscal fascicle (PMF) disruption or assessing lateral meniscal dynamics under physiological loading conditions. This study aimed to evaluate the diagnostic performance of a standardized ultrasound-based method for assessing the PMF and to explore the association between lateral meniscal dynamics under weight-bearing conditions and lateral meniscal hypermobility in patients with medial knee osteoarthritis. 48 patients who underwent medial opening-wedge high tibial osteotomy or unicompartmental knee arthroplasty were included. Ultrasound examinations of anterior, posterosuperior, and posteroinferior PMF, and lateral meniscus posterior extrusion (LMPE) were performed in the prone and standing positions. The diagnostic performance of ultrasound-based PMF assessment was evaluated using receiver operating characteristic (ROC) analysis with intraoperative findings as the reference standard. Lateral meniscal hypermobility was examined using paradoxical motion on ultrasound and intraoperative Tom's test, and its association with PMF disruption was investigated. ROC analysis demonstrated significant areas under the curve (AUCs) for the posterosuperior PMF (AUC, 0.75; 95% confidence interval, 0.57-0.94) and posteroinferior PMF (AUC, 0.73; 95% confidence interval, 0.59-0.87). Paradoxical motion was observed in 31.3% of patients, whereas Tom's test was positive in 43.8%. Paradoxical motion was associated with posterosuperior PMF disruption (odds ratio, 7.08; P = 0.006) on US, while Tom's test positivity was associated with both posterosuperior PMF (odds ratio, 4.09; P = 0.04) and posteroinferior PMF disruption (odds ratio, 7.04; P = 0.01).' Dynamic weight-bearing ultrasound demonstrated moderate diagnostic performance for detecting disruption of the posterosuperior PMF and posteroinferior PMF and may allow assessment of functional lateral meniscal instability, suggesting that it may serve as a potentially useful preoperative screening adjunct. These findings may inform preoperative suspicion of lateral meniscus hypermobility.