In vivo movement interrelationships among the medial meniscus, joint capsule, and semimembranosus during tibial rotation.

The meniscal position within the knee is critical to maintain normal knee function. The joint capsule might dynamically coordinate the medial meniscus (MM) by transmitting a semimembranosus action. However, their interrelationships in vivo are unclear. We aimed to determine relationships among the MM, joint capsule, and semimembranosus during passive tibial external-internal and isometric tibial internal rotation at the medial and posteromedial knees of 10 healthy individuals in vivo using ultrasound. We analyzed images of the MM and joint capsule locations at the medial and posteromedial knee and the velocity waveform similarity of each structure during rotational tasks. Both isometric internal rotation with semimembranosus action and passive tibial external rotation displaced the MM inward at the medial knee. The MM and joint capsule during these MM displacements coordinately moved with more than moderate cross-correlation coefficients (passive external and isometric internal rotations, ≥ 0.54 and ≥ 0.90, respectively). The movements of the MM and joint capsule to the semimembranosus during isometric internal rotation also coordinated with moderate cross-correlation coefficients (≥ 0.62). Therefore, the joint capsule might dynamically coordinate the MM by transmitting semimembranosus action. Whether increased tibial internal rotation or semimembranosus shortening causes MM extrusion awaits further investigation.

Effects of short foot exercises with ultrasound bio-feedback on motor learning and foot alignment: A double blinded randomized control trial.

BACKGROUND: Short foot exercises (SFE) take a long time to master and require a feedback tool to improve motor learning. OBJECTIVE: This study aimed to investigate the effect of bio-feedback of talonavicular joint movements in learning SFE with ultrasound (US) imaging. METHODS: This study included thirty-one healthy volunteers and was designed as a double-blind randomized control trial. Subjects were randomly assigned to one of two groups: the control group, which performed SFE under verbal instruction, and the US bio-feedback (USBF) group, which performed SFE with real-time bio-feedback of the talonavicular joint alignment. All subjects underwent two sessions of 5 minutes each, and SFE was performed as a self-exercise, between sessions, for one week. The difference in foot length and navicular height were assessed at baseline, after Session 1, before Session 2, and one week after Session 2. These differences were compared between the two groups using the Mann-Whitney U test. RESULTS: In terms of navicular height change, the USBF group (7.5 ± 4.3 mm) was significantly higher than the control group (4.2 ± 3.3 mm) one week after session 2 (p= 0.04, effect size = 0.86). CONCLUSION: SFE with USBF is an effective intervention for performing SFE.