Ankle Orthosis Research Articles

The influence of an ankle orthosis on the talar and calcaneal motions in chronic lateral instability of the ankle. A stereophotogrammetric analysis.

The mechanical support provided by a semirigid ankle orthosis was tested in 14 ankles with symptoms of chronic lateral instability by use of stereophotogrammetric analysis. Talar and calcaneal rotations were measured with and without the Strong ankle orthosis during manual adduction test and adduction test with a predetermined torque (5 N-m). Significant reduction of talar and calcaneal plantar flexion, internal rotation, and varus angulation was noted when the orthosis was applied. The results of this study suggest that the semirigid orthosis may provide enough external support to prevent ankle sprains and to protect ligament reconstructions.

Comparison of DonJoy® Ankle Ligament Protector and Aircast® Sport-Stirrup™ Orthoses in Restricting Foot and Ankle Motion before and after Exercise

Clinicians are often faced with the task of selecting ankle orthoses for patients who have incurred an ankle sprain injury. The purpose of this study was to compare the effectiveness of the Donjoy® Ankle Ligament Protector and the Aircast® Sport-Stirrup® in limiting foot and ankle motion before and after exercise. Subjects were eight males and eight females with no history of ankle injury during the 6 months prior to testing, neurological condition, lower extremity arthritis, lower extrem ity fracture, or cardiac or balance problems. A Biodex dynamometer and computer were used to impose passive moments and to measure eversion and inversion prior to application of the ankle orthoses, following application, and following 10 minutes of figure-of-eight running and 20 unilateral toe raises. Both ankles of each subject were assessed for each ankle orthosis. Subjects also rated the orthoses for comfort, stability, and cosmetic acceptability. Both ankle orthoses significantly reduced eversion and inversion follow...

Isometric Strength of Rearfoot Inversion and Eversion in Nonsupported, Taped, and Braced Ankles Assessed by a Hand-Held Dynamometer

Previous studies have reported a reduction of athletic performance while wearing ankle orthoses. The present study investigated whether or not this observed reduction in performance was the result of a restriction of the associated muscles by the orthoses. Specifically, 36 male undergraduate students participated in this study to compare the effects of unsupported, nonelastic adhesive-taped, and Swede-O, New Cross, Air-Stirrup, and STS braced ankles on isometric strength of rearfoot inversion and eversion as assessed by a hand-held dynamometer. Subjects were stabilized in a seated position so that lower limb movement was restricted to the ankle. Each subject performed isometric inversion and eversion contractions under all six ankle conditions with the dominant foot. The isometric force was recorded from each of three trials during rearfoot inversion and eversion under each support condition. One-way repeated measures ANOVAs failed to detect any significant differences between the six testing conditions for inversion and eversion for both mean and peak force values. No alterations were observed in the isometric forces recorded during rearfoot inversion and eversion, thus, indicating that the orthoses did not constrict the lower leg musculature. These results suggest that, when selected by the clinician, any brace used in this study would not be detrimental to lower leg strength. J Orthop Sports Phys Ther 1992;15(5):229-235.

A Comparison of the Passive Support Provided by Various Ankle Braces

This research was funded in part by a grant from the Ferrante and Jackson Physical Therapy Research Fund. Recent criticism in the literature regarding the effectiveness and costs of ankle taping has lead to an increased use of commercial ankle braces. This study compared the effectiveness of four commercially available ankle braces in limiting range of motion at the ankle before and after a brief exercise session. Twenty-seven healthy subjects, ages 18-36, were tested across all four bracing conditions. For each brace application, a combined passive inversion-eversion movement was evaluated three times: 1) prebrace application, 2) immediate postbrace application, and 3) following a 10 min exercise session. Subjective ratings of brace comfort, support, and preference were also documented. All four braces significantly limited more motion compared to the unbraced ankle, both before and after exercise (p </= 0.05). Additionally, the Aircast(R) Sport-Stirrup and Ankle Ligament Protector significantly limited more ankle motion than the Swede-O Ankle Support(R) and Kallassy Ankle Support(R), both before and after exercise (p </= 0.05). Subjectively, the Sport-Stirrup was perceived as the brace providing the most support, but the Kallassy was the most comfortable and most preferred of the four braces studied. These findings demonstrate that provided support must be balanced with perceived comfort in the prescription of an ankle orthosis. J Orthop Sports Phys Ther 1992;15(1):10-18.

Posturographic evaluation of the proprioceptive effect of ankle orthoses in healthy volunteers

This study analyses the proprioceptive effect of wearing a unilateral and then bilateral ankle orthosis on 34 healthy volunteer subjects by posturography. An elastic orthosis with a ligamentous support band was used, and evaluation was performed by a posturographic statokinesimetric platform. Three tests, one without an orthosis, one with one orthosis, and one with two orthoses, were recorded for each volunteer. The results and statistical analyses demonstrated a significant difference in the antero-posterior measurement between the test without ankle orthosis and the tests with one and with two orthoses. This study provides information about the prophylactic effect of wearing a flexible support; it appears that there are important inter-individual variations in postural equilibrium, and the wearing of prophylactic ankle orthoses should be reserved for subjects after a posturographic examination.

A Comparative Support Evaluation of Three Ankle Orthoses Before, During, and After Exercise

The purpose of this study was to compare the support effectiveness of three ankle orthoses before, during, and after a 90 minute softball practice. The effect of each support method on the athletes' base running ability was also assessed. Twenty-four ankles with no history of ankle pathology were divided into three groups (n = 8), and randomly assigned to wear one of the ankle devices. Passive inversion-eversion ROM was measured on an ankle stability test instrument during five testing sessions: 1) pre-support, 2) pre-exercise, 3) 20 minutes during exercise, 4) 40 minutes during exercise, and 5) post-exercise. The data analyses revealed significant differences in support effectiveness among the three orthoses (p < 0.01). The support provided post-exercise by the Swede-O was reduced by 35% compared to its initial level of support. The support reductions for the Air-Stirrup and the Ankle Ligament Protector (ALP) were 12% and 8%, respectively. The application of the ALP and the Swede-O orthoses had no significant effect on the athletes' ability to run the bases; while the Air-Stirrup application resulted in significantly slower base running times. These results suggest that the ALP may be more effective than the other orthoses tested in guarding against initial inversion sprain trauma and protecting the ankle joint against chronic re-injury. J Orthop Sports Phys Ther 1990;11(10):453-466.

A Comparative Isokinetic Evaluation of a Functional Ankle Orthosis on Talocalcaneal Function

The purpose of this study was to determine the effectiveness of a semirigid orthosis in restricting ankle inversion-eversion range of motion (ROM), and evaluate its effect on subjects' ability to produce muscular torque, during pre- and post-exercise test conditions. Thirty healthy subjects, 15 males and 15 females, with no history of right ankle injury were evaluated. Active ankle inversion-eversion torque and angular displacement were measured on a LIDO(R) isokinetic system, with the subjects' right ankle positioned in 0 degrees of plantarflexion. T-tests for paired samples at the 0.001 confidence level revealed that the orthosis demonstrated significant inversion-eversion range restrictive capabilities; did not interfere with maximum inversion-eversion torque production; and retained its support effectiveness following 20 minutes of dynamic exercise. The results suggest that the tested orthosis may be an effective prophylactic in preventing ankle sprains and beneficial to individuals with chronic ligamentous instability. J Orthop Sports Phys Ther 1989;11(6):245-252.

Exercise moderation of foot function during walking with a re-usable semirigid ankle orthosis

A study was conducted to investigate the effects of a re-usable semirigid ankle orthosis on the support phase of the walking stride in both pre- and post-exercise conditions. Ten young, adult males were required to complete ten trials in each of four orthosis/no orthosis and pre-/post-exercise conditions. Data were collected via a force platform and a high speed camera. The analysis consisted of the evaluation of selected ground reaction force parameters and kinematic parameters describing rearfoot motion. The exercise regimen consisted of 70 maximal eccentric actions of the ankle everters, with 15 s between each action. The results revealed significant differences between the orthosis/no orthosis conditions for the variables describing the mediolateral action of the ankle during walking. Only the rearfoot touchdown angle was affected by the exercise regimen. The data indicated that the semirigid orthosis moderated ankle joint mechanics, although the measured values were within normal bounds.

Modification of Spastic GAIT through Mechanical Damping

A feasibility study investigating the use of dissipative mechanical damping loads to modify spastic gait is currently underway. The concept of a mechanically damped orthosis is based on a hypothesis citing velocity-dependent stretch reflexes as a causal factor in certain spastic gait abnormalities, such as equinus and backkneeing. Accordingly, the experimental subject was selected on the basis of a velocity-dependent reflex, as established through a series of seated "ankle stretch" experiments. To facilitate study of a variety of damping schemes and iteration towards optimal damping parameters, a wearable, electromechanical, computer-controlled ankle orthosis simulator was designed and constructed. The simulator is instrumented to measure important gait variables so that effects of the applied mechanical loads on the subject's gait patterns can be assessed. Initial orthosis simulation experiments have begun. The most effective damping schemes will be cooinared with rigid bracing through filmed gait analysis.

The foot and footwear.

Coming from a country where the majority of people walk in unshod feet and where shoes are an expensive luxury, I would like to offer some unconventional thoughts which might provide a global overview of the problems involved in the design of footwear and foot and ankle orthoses. I was brought up with the traditional concept of the foot being merely a static tripod or a semi-rigid support for superincumbent body weight. The arches of the foot were held to be very important and fie height of the longitudinal arch was correlated with a superior kind of foot. We owe it to Hicks (1961) of Birmingham who taught us to clearly differentiate between a beam, an arch and a truss, and the role of muscles and the plantar aponeurosis in the weight bearing and balancing mechanism of the foot. But the foot can no longer be viewed as a mere weight-bearing device meant only for standing. It has evolved, as the bioengineering team at the University of California (1947) has been telling us over the last two decades, as a dynamic mechanism functioning as an integral part of the locomotor system. The human foot is primarily meant for walking and it is important to understand its behaviour in the walking cycle. The foot is a remarkably mobile mechanism, adapting itself to the contours of the ground as well as responding to the forces transmitted via the suprapedal segments from above. By supinating and pronating, it causes the weight fine to follow a curved pathway leading to an even load distribution on the metatarsal heads. It becomes supple as it is grounded from heel strike to foot flat, and rigid as it prepares itself for heel rise and the final take-off. There is a locking mechanism in the foot, operated