Ultrasonographic Evaluation of Medial Meniscal Extrusion During Common Orthopedic Physical Therapy Examination Procedures: An Observational Study

OBJECTIVE: To compare medial meniscal extrusion during supine knee extension overpressure and standing using ultrasound imaging. DESIGN: Cross-sectional repeated measures. METHODS: Thirty-four participants contributed 63 knees that were examined in the following positions: supine relaxed, during supine knee extension overpressure, and during standing. The primary outcome was meniscal extrusion measured using ultrasound imaging. RESULTS: Repeated-measures analysis of variance comparing meniscal extrusion across positions found significant within-group (F = 80.9, df = 3, P = .000) and between-group (F = 17.9, df = 1, P = .000) differences. There were no significant differences between knee extension overpressure and standing (F = .397, df = 2, P = .643) or interaction between age category and position examined (F = .276, df = 3, P = .821). Additional analyses revealed no association between meniscal extrusion and sex, race/ethnicity, or knee examined and weak associations between body mass index (BMI) and position examined (r = .434-.507). CONCLUSION: We found that supine knee extension overpressure produced comparable meniscal extrusion as standing, which may be clinically meaningful because some patients with knee pain cannot be reliably or safely examined in standing. JOSPT Open 2024;2(2):134-140. Epub 8 January 2024. doi:10.2519/josptopen.2024.0918