Proposals for talonavicular joint assessment using ultrasound imaging and its reliability and validity.

[Purpose] We aimed to develop a noninvasive specific ultrasonographic assessment of the talonavicular joint during loading to facilitate the analysis of treatment of flatfoot. [Participants and Methods] Sixty healthy participants underwent ultrasound imaging of the talonavicular joint while sitting and standing. The talonavicular angle was defined as the intersection of the line connecting the navicular and talar heads and the line connecting the talar head and sustentaculum tali. Talonavicular coverage was assessed using X-ray images of 15 participants. [Results] Ultrasonographic assessment of the talonavicular joint showed a lateral shift of the navicular relative to the head of the talus from sitting to standing. The talonavicular angle was significantly larger when standing than in the sitting position. The difference in talonavicular angle values between sitting and standing significantly correlated with the differences in the talonavicular coverage values. [Conclusion] We showed that ultrasonographic talonavicular angle assessment has good reliability and moderate validity for detecting significant alignment changes in the talonavicular joints due to loading. In the future, this evaluation method should be performed before and after exercise therapy to assess and develop appropriate exercise therapy for flatfoot.

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.

Investigation of the relationship between the thickness of the plantar calcaneonavicular ligament and plantar fascia in patients with plantar fasciitis.

BACKGROUND: Although patients with plantar fasciitis show spring ligament laxity, the thickness of the spring ligament in patients with plantar fasciitis remains unclear. This study aimed to elucidate the morphological characteristics of the spring ligament in patients with plantar fasciitis based on an ultrasound imaging system (US). METHODS: Thirty feet of 30 patients (painful group) diagnosed with plantar fasciitis at our hospital and thirty feet of 30 healthy volunteers (healthy group) without plantar pain were investigated. The thicknesses of both the spring ligament and plantar fascia were assessed via a US statistical comparison of the spring ligament and plantar fascia thickness between the painful and healthy groups. This was performed using Welch's t-test, and the significance level was set at p < 0.01. In addition, Pearson's correlation coefficient was calculated to assess the correlation between the spring ligament and plantar fascia thickness in the two groups, and the significance level was set at p < 0.01. RESULTS: The spring ligament thickness in the painful group was significantly lower than that in the healthy group (p < 0.001). The thickness of the plantar fascia in the painful group was significantly greater than that in the healthy group (p = 0.03). In addition, the correlation between the spring ligament and plantar fascia thickness was moderately negative (r = -0.42, p = 0.001). The thicker the plantar fascia in the subjects, the thinner was the spring ligament. CONCLUSIONS: The thickness of the spring ligament in patients with plantar fasciitis decreased. The thinning of the spring ligament was negatively correlated with the thickening of the plantar fascia as per the US evaluation. Based on the spring ligament thinning determined via US evaluation, interventions such as insoles from an early stage could prevent the onset of plantar fasciitis.