Effect of simulated joint instability and bracing on ankle and subtalar joint flexibility

Acute and Chronic Subtalar Joint Instability: Does It Really Exist?

Acute and chronic subtalar instability and commonly coexistent with other hindfoot pathology but can be difficult to diagnose. A high degree of clinical suspicion is required as most imaging modalities and clinical maneuvers are poor at detecting isolated subtalar instability. The initial treatment is similar to ankle instability, and a wide variety of operative interventions have been presented in the literature for persistent instability. Outcomes are variable and limited.

Protection by Ankle Brace for Lower-Extremity Joints in Half-Squat Parachuting Landing With a Backpack

Half-squat parachuting landing is a kind of activity with high impact force. Injuries on lower-extremity joints are common in half-squat parachuting landing and would be increased with a backpack. An ankle brace was used to prevent ankle injuries in landing. However, few quantitative studies reported about the protection of an ankle brace for lower-extremity joints in half-squat parachuting landing with a backpack. This study focused on evaluating the protective effects of an ankle brace in half-squat parachuting landing with a backpack. Seven male participants landed from 120 cm with a backpack and an ankle brace. Each participant performed three landing trials on every experimental condition. Kinetics and kinematics of the hip, knee, and ankle were analyzed. It was found that the ankle brace did not significantly affect the ground reaction force with backpack but increased the ground reaction force from 14.7 ± 2.0 bodyweight to 16.2 ± 1.9 bodyweight (p = 0.017) without the backpack. The ankle brace significantly (p < 0.05) decreased the angular displacement, angular velocity, and angular acceleration of the ankle both without and with the backpack. In conclusion, the ankle brace could restrict ankle motion and significantly increase ground reaction force without the backpack. However, the ankle brace did not significantly influence ground reaction force and still restricted ankle motion with the backpack. Therefore, the ankle brace was more effective in half-squat parachuting landing with the backpack than no-backpack landing.

Efficacy of a semirigid ankle brace in reducing mechanical ankle instability evaluated by 3D stress-MRI

Background

Novel imaging technologies like 3D stress-MRI of the ankle allow a quantification of the mechanical instability contributing to chronic ankle instability. In the present study, we have tested the efficacy of a semirigid ankle brace on joint congruency in a plantarflexion/supination position with and without load.

Methods

In this controlled observational study of n = 25 patients suffering from mechanical ankle instability, a custom-built ankle arthrometer implementing a novel 3D-stress MRI technique was used to evaluate the stabilizing effect of an ankle brace. Three parameters of joint congruency (i.e., 3D cartilage contact area fibulotalar, tibiotalar horizontal and tibiotalar vertical) were measured. The loss of cartilage contact area from neutral position to a position combined of 40° of plantarflexion and 30° of supination without and with axial load of 200 N was calculated. A semirigid ankle brace was applied in plantarflexion/supination to evaluate its effect on joint congruence. Furthermore, the perceived stability of the brace during a hopping task was analyzed using visual analogue scale (VAS).

Results

The application of a semirigid brace led to an increase in cartilage contact area (CCA) when the foot was placed in plantarflexion and supination. This effect was visible for all three compartments of the upper ankle joint (P < 0.001; η² = 0.54). The effect of axial loading did not result in significant differences. The subjective stability provided by the brace (VAS 7.6/10) did not correlate to the magnitude of the improvement of the overall joint congruency.

Conclusions

The stabilizing effect of the semirigid ankle brace can be verified using 3D stress-MRI. Providing better joint congruency with an ankle brace may reduce peak loads at certain areas of the talus, which possibly cause osteochondral or degenerative lesions. However, the perceived stability provided by the brace does not seem to reflect into the mechanical effect of the brace.

Trial registration The study protocol was prospectively registered at the German Clinical Trials Register (#DRKS00016356).

Statistical ankle-shape and pressure analysis for design of elastic tubular bandage

Ankles can benefit from the elastic tube bandage (ETB) by providing the ankle joint with compression, but partial high- or low-pressure leads to body discomfort. The aim of this paper is to propose a method for analyzing the ankle shape with the fabric compression which is basis on the comfortable pressure on human body. First, a standard model of ankle is established from the scanned data of 306 samples, and the mapping of the fabric shape curves on ankle were constructed by the U-direction convex curves of the model. The positions or areas of maximum and minimum pressure are then marked by extracting the curvatures of the fabric shape curves. According to the Laplace's Law, the sizes of ETBs can be calculated given that the value of comfortable pressure on human body is the maximum one. The data of calculation is approximate to the relevant previous studies which has the same parameters of ETBs. Nine groups of the ankle shapes from the database are discussed, each group has a proportional coefficient to the standard model, and the result shows that six sizes of ETBs with comfort pressure match for the nine groups. These can be applied to the comfort design, and the method proposed can boost size customization of ETBs, as well as will inspire the research on other elastic compression garments.

Effects of Kinesiotape vs Soft and Semirigid Ankle Orthoses on Balance in Patients With Chronic Ankle Instability: A Randomized Controlled Trial

BACKGROUND

Chronic ankle instability (CAI) is a frequent complication of ankle sprain that may be associated with long-term consequences. Although taping and bracing are common interventions that are widely used by clinicians and athletic trainers for patients with CAI, no studies have compared the effects of kinesiotaping and bracing on balance performance in these patients. The present study aimed to compare the effects of ankle kinesiotaping, a soft ankle orthosis, and a semirigid ankle orthosis on balance performance in patients with CAI.

METHODS

Sixty patients with CAI were randomly assigned to 4 groups that received kinesiotaping, a soft orthosis, a semirigid orthosis, or no treatment (control group). Dynamic and static balance were measured with the modified Star Excursion Balance Test, single leg hop test, and single leg stance test before and after a 4-week intervention period.

RESULTS

Significant between-group differences were seen in all evaluated outcomes (P ≤ .003). The lowest reach distances in all directions in the modified Star Excursion Balance Test were found in the control group, and these patients also had a significantly shorter measured distance in the single leg hop test, and more errors in the single leg stance test compared with the 3 intervention groups. No significant differences were found among the 3 intervention groups.

CONCLUSION

Use of kinesiotaping and a soft or a semirigid ankle brace for 4 weeks were all beneficial in improving static and dynamic balance in individuals with CAI. None of the interventions was superior to the other 2.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.