Effect of the AirStirrup in Controlling Ankle Inversion Stress

Review of ankle inversion sprain simulators in the biomechanics laboratory

Ankle inversion ligamentous sprain is one of the most common sports injuries. The most direct way is to investigate real injury incidents, but it is unethical and impossible to replicate on test participants. Simulators including tilt platforms, trapdoors, and fulcrum devices were designed to mimic ankle inversion movements in laboratories. Inversion angle was the only element considered in early designs; however, an ankle sprain is composed of inversion and plantarflexion in clinical observations. Inversion velocity is another parameter that increased the reality of simulation. This review summarised the simulators, and aimed to compare and contrast their features and settings.

Prophylactic ankle bracing reduces rearfoot motion during sudden inversion

The purpose of this study was to evaluate the effects of ankle bracing on rearfoot angular displacement and angular velocity during a sudden inversion movement. A 1 x 3 factorial design was used. The single independent variable was ankle brace condition with three levels: semi-rigid, lace-up and control. The two dependent variables were rearfoot average angular displacement and average angular velocity. Twenty-four healthy volunteers participated in this study. A motion analysis system was used to capture, model and calculate two-dimensional rearfoot motion while the subjects' ankle/foot complex was inverted to 35 degrees on a platform device. All subjects performed five trials of each ankle brace condition, and the average of these trials was used for statistical analysis. The semi-rigid brace significantly reduced rearfoot angular displacement and angular velocity compared with the lace-up (P<0.05) and control conditions (P<0.05). Additionally, the lace-up style brace demonstrated significantly less rearfoot angular displacement and angular velocity compared with the control condition (P<0.05). These results demonstrate that a semi-rigid ankle brace is more superior then a lace-up style brace in limiting rearfoot angular displacement and angular velocity. Moreover, the lace-up style brace offers significant restriction of these measures compared with no support.

A Comparative Analysis of Selected Ankle Orthoses during Functional Tasks

Context:

Ankle bracing has been used for many years in an attempt to prevent lateral ligamentous injuries of the ankle by restricting joint range of motion (ROM).

Objective:

To examine the influence of ankle bracing on ROM and sport-related performance.

Design:

Repeated measures.

Setting:

Biomechanics laboratory.

Participants:

30 volunteers. None reported ankle trauma within 2 years preceding the study or had other orthopedic conditions that would have affected physical performance.

Intervention:

Three brace conditions (McDavid A101™, Perform-8™ Lateral Stabilizer) were assessed during performance of the vertical jump and shuttle run.

Main Outcome Measures:

shuttle-run time, vertical jump height, inversion, and plantar flexion ROM.

Results:

Both braces restricted plantar flexion and inversion ROM and caused no change in shuttle-run time or vertical jump height.

Conclusions:

Our results indicate that bracing the ankle joint increases external lateral support to the joint without significantly restricting functional ability.

Influence of ankle support on joint range of motion before and after exercise: a meta-analysis

STUDY DESIGN

Meta-analysis.

OBJECTIVE

To evaluate the effects of different types of ankle support on ankle and foot joint range of motion before and after activity using meta-analysis procedures.

BACKGROUND

The effects of ankle support on joint range of motion before and after exercise has been extensively studied, but the results among studies are not consistent. Obtaining knowledge from synthesizing the available literature with a meta-analysis can provide a greater understanding of these effects.

METHODS AND MEASURES

A total of 253 cases from 19 studies were examined and included in this analysis. The treatment variables were ankle support with 3 levels (tape, lace-up, and semirigid) and time with 2 levels (before exercise and after exercise). Standardized effect sizes were computed for inversion, eversion, dorsiflexion, and plantar flexion range of motion to measure the difference between control and treatment groups at each point in time. Effect sizes were analyzed using a mixed-model factorial analysis of variance.

RESULTS

Before exercise, the semirigid condition (-2.97 +/- 0.63) demonstrated greater restriction compared with the tape (-2.33 +/- 0.38) and lace-up conditions (-2.18 +/- 0.86) for inversion range of motion. After exercise, the semirigid condition (-3.85 +/- 0.64) restricted inversion range of motion more than the tape (-1.07 +/- 0.20) and lace-up (-1.56 +/- 0.29) conditions. No differences were found between the mean effect sizes for the tape and lace-up conditions before and after exercise. With respect to eversion range of motion, the semirigid support (-2.69 +/- 0.43) provided greater restraint compared with the tape (-1.00 +/- 0.21) and lace-up (-1.40 +/- 0.47) conditions. The lace-up condition also displayed greater support compared with tape alone. For dorsiflexion range of motion, greatest overall support was provided by the tape condition (-0.94 +/- 0.06) compared with the lace-up condition (-0.51 +/- 0.06).

CONCLUSIONS

The greatest restriction of motion in the frontal plane was offered by the semirigid support condition, whereas taping offered the most support for limiting dorsiflexion range of motion. The results of this study may help clinicians make rational decisions concerning the selection of ankle appliances for preventing acute or chronic reinjury.

The prevention of ankle sprains in sports. A systematic review of the literature

To assess the published evidence on the effectiveness of various approaches to the prevention of ankle sprains in athletes, we used textbooks, journals, and experts in the field of sports medicine to identify citations. We identified 113 studies reporting the risk of ankle sprains in sports, methods to provide support, the effect of these interventions on performance, and comparison of prevention efforts. The most common risk factor for ankle sprain in sports is history of a previous sprain. Ten citations of studies involving athletes in basketball, football, soccer, or volleyball compared alternative methods of prevention. Methods tested included wrapping the ankle with tape or cloth, orthoses, high-top shoes, or some combination of these methods. Most studies indicate that appropriately applied braces, tape, or orthoses do not adversely affect performance. Based on our review, we recommend that athletes with a sprained ankle complete supervised rehabilitation before returning to practice or competition, and those athletes suffering a moderate or severe sprain should wear an appropriate orthosis for at least 6 months. Both coaches and players must assume responsibility for prevention of injuries in sports. Methodologic limitations of published studies suggested several areas for future research.

Effects of Bracing on Isokinetic Torque for the Chronically Unstable Ankle

Because the effects of bracing on dynamic torque production are unknown, the purpose of this study was to determine the effects of flexible and semirigid braces on isokinetic torque production at varying velocities produced by the invertor and evertor muscles for the chronically unstable ankle. Ten healthy and 14 chronically unstable ankles were tested, with a repeated-measures design including joint motion (inversion, eversion), muscle contraction type (concentric, eccentric), brace condition (unbraced, flexible, semirigid), and velocity (60, 120, 180, 240°/s). Multiple ANOVAs with repeated-measures and Bonferroni-adjusted comparisons were performed. Results showed that the chronically unstable ankle was significantly weaker than the healthy ankle, regardless of muscle contraction type or joint motion, and that bracing did not deter the muscles' ability to produce peak torque either concentrically or eccentrically. The chronically unstable ankle requires enhanced strengthening, particularly eccentrically and at higher, more functional velocities. Bracing can reduce or prevent injury to the ankle without deterring torque production.

Braced for impact: reducing military paratroopers' ankle sprains using outside-the-boot braces

BACKGROUND

Ankle injuries account for 30 to 60% of all parachuting injuries. This study was designed to determine if outside-the-boot ankle braces could reduce ankle sprains during Army paratrooper training.

METHODS

The randomized trial involved 777 volunteers from the U.S. Army Airborne School, Fort Benning, Ga. Of this group, 745 completed all study requirements (369 brace-wearers and 376 non-brace-wearers). Each volunteer made five parachute jumps, for a total of 3,674 jumps.

RESULTS

The incidence of inversion ankle sprains was 1.9% in non-brace-wearers and 0.3% in brace-wearers (risk ratio, 6.9; p = 0.04). Other injuries appeared unaffected by the brace. Overall, 5.3% of the non-brace group and 4.6% of the brace group experienced at least one injury. The risk ratio for injured individuals was 1.2:1 (non-brace to brace groups; p = 0.65).

CONCLUSION

Inversion ankle sprains during parachute training can be significantly reduced by using an outside-the-boot ankle brace, with no increase in risk for other injuries.

Effectiveness of external ankle support. Bracing and taping in rugby union

Ankle inversion sprain is common in rugby. This review outlines research evidence relating to the effects of external ankle support by means of bracing and taping, on the incidence of ankle injuries, how performance is affected by support, how support may act at the joint (with respect to end range of motion, strength, resistive torque, muscle activation patterns and proprioception) to prevent injury, and how exercise changes the effectiveness of support. In addition, the implications of the laws of rugby for the use of external support are discussed. Prospective epidemiological studies have shown a decrease in the incidence of ankle injury with external ankle support use. The effectiveness of external ankle support was dependent upon the material properties and application method of the tape or brace, and on the athlete's status of ankle stability or previous injury. Experimental studies have indicated that the degree of ankle inversion restriction provided, and the degree of loss of restriction after exercise, were dependent upon the external support tested. External ankle support has been reported to have no effect on performance, or to have an adverse effect on performance in a variety of movement tasks. No prophylactic external ankle support has been shown to improve performance. If an external support is to provide mechanical support to a ligament it should exceed the strength of the ligament, which for the anterior fibular ligament is a force limit of between 6 and 56 kg. Tape can provide only limited mechanical support of the ankle joint complex, but it may have proprioceptive effects. Taping may work as a psychological reminder, so that the athlete consciously moderates lower limb-loading behaviour. There is equivocal evidence of the effect of brace use on ground reaction force excursions, balance ability and ankle strength. It is concluded that while there have been many investigations of the effects of tape and some forms of brace on ankle range of motion with and without exercise, there is equivocal evidence regarding the mechanism by which an external support acts. It is recommended that future research address the effects of external ankle support during dynamic exercise and that brace manufacturers utilise the information in the development of future brace designs to help reduce the risk of ankle inversion sprain injury. As external support can decrease the incidence of ankle inversion sprain the International Rugby Board should consider the use of ankle braces in rugby, allowing for stiff lateral components of the brace.

Functional evaluation of the 10-year outcome after modified Evans repair for chronic ankle instability

The Evans tenodesis is an operative treatment for chronic ankle instability with good short-term results. The disadvantage of impaired hind foot kinematics and restricted motion has been described, and only few reports of long-term results can be found. No techniques have been used to assess the outcome objectively. We wanted to determine whether a modified Evans procedure led to a satisfactory clinical and functional outcome. Nineteen patients were available at a 10-year follow-up. The clinical examination included a detailed questionnaire and stress radiographs. Foot function was evaluated with plantar pressure distribution measurements during walking and peroneal reaction time measurements elicited on a rapidly tilting platform (recorded with surface electromyography). High subjective patient satisfaction was contrasted with a high rate of residual instability, pain, and swelling. The radiographs showed an increased number of exostoses. The gait analysis revealed reduced peak pressures under the lateral heel and increased values under the longitudinal arch. The reaction times of the peroneal muscles were shorter on the operated side (significant: peroneus longus). The persistent clinical problems as well as the functional changes indicate that the disturbed ankle joint kinematics permanently alter foot function and may subsequently support the development of arthrosis. Therefore, the Evans procedure should only be applied if anatomical reconstruction of the lateral ankle ligaments is not feasible.

Long-Term Use of a Softshell Prophylactic Ankle Stabilizer on Speed, Agility, and Vertical Jump Performance

The purpose of this study was to determine the effect of a softshell prophylactic ankle stabilizer (PAS) on performance in events involving speed, agility, and vertical jump during long-term use. The events examined were the 24.384-m sprint, 12.192-m shuttle ran, and vertical jump. Subjects were high school basketball players who were randomly assigned to either a PAS (n = 11) or a nonbraced control (n = 13) group. Results of the study revealed that the softshell PAS had no significant effect on any of the three performance events tested over a 3-month basketball season. However, there was a significant difference in 24.384-m sprint and 12.192-m shuttle run times across test sessions regardless of treatment group. In conclusion, the softshell PAS neither enhanced nor inhibited performance in activities involving speed, agility, or vertical jump during long-term use.

Role of ankle taping and bracing in the athlete

Adhesive tape is often used to help athletes recover from ligament sprains of the ankle or to prevent further injury. The choice of taping technique or material is often decided by personal preference, superstition, or anecdote. More recently, the use of ankle braces has become more prevalent, but reasons for their use are similarly variable. As ankle sprains are a major cause of an athlete's disability and time off sport, the choice of the method of support should be more scientifically reasoned. This paper attempts to review the literature concerning the effects of various methods of ankle support on swelling, stability, range of movement, proprioception, muscle function, gait, and performance tests. There is still some contradiction in the literature about the effects of taping and braces in both the acute and chronic phases of ligament sprains of the ankle.

Restriction of foot supination by ankle braces in sudden fall situations

OBJECTIVE: To investigate the restriction of foot supination in different shoe orthotic combinations for unexpected ankle turns. DESIGN: A supination platform was used to experimentally induce sudden ankle turns. BACKGROUND: This study expanded on previous investigations of the effectiveness of different ankle braces and the influence of shoe material on foot supination. METHODS: For 21 male subjects pressure distribution data, achilles tendon angle, and supination velocity were collected. A comparison between a shoe with cut upper material and an intact shoe was done to show the influence of upper material on supination. The effectiveness of four different orthotics inside of an intact shoe were tested in comparison to the same shoe without ankle brace. Additionally, subjects rated their perceived supination movement of the foot. RESULTS: Between experimental conditions no large differences for the pressure distribution patterns were found. Three of the ankle braces reduced foot supination as well as supination velocities. More than two times lower supination values were measured for a footwear condition in which the upper material was cut away. Already during the free-fall most ankle braces caused a substantial reduction of foot inversion. CONCLUSION: The experiments demonstrated the influence of the upper material of a shoe and different orthotics on foot supination. Biomechanical measurements are necessary because of limited capabilities of subjects in detecting subtalar angular motions. RELEVANCE: This study investigated the effectiveness of different shoe conditions and ankle braces under experimental conditions that simulated unexpected ankle turns, the most frequent causes of sport injuries. The results of the study provide insights into which factors influence the amount of foot supination during unexpected ankle turns.

Effectiveness of external orthotic support on passive soft tissue resistance of the chronically unstable ankle

Functional ankle instability, orthoses, and passive resistive torque tolerated have not been researched. The purpose of the study was to evaluate the passive resistance torque exerted by a flexible and semirigid orthosis for individuals with chronic instability. Twenty-two subjects were evaluated on the passive ankle resistance unit during unbraced, flexible, and semirigid brace conditions. Data from the final three trials for each condition were analyzed using a multiple analysis of variance with repeated measures for resistive torque and inversion range of motion. The semirigid and flexible braces tolerated significantly greater torque forces and less inversion range than the unbraced condition (P < 0.000). External orthotic support, in particular that of a semirigid orthosis, may be beneficial toward reducing injury or be an effective prophylactic for the healthy population.

Is prophylactic bracing of the ankle cost effective?

The ankle joints of 14 healthy volunteers and 16 patients with unstable ankle joints were tested for their functional and proprioceptive capabilities. All of them were active athletes. Three tests were used: the single-leg stance test, the single-leg jumping course test, and the angle-reproduction test. The influence of three stabilization devices--the lace-on brace (Mikros), the stirrup brace (Aircast), and taping--on the proprioceptivity of stable and unstable ankle joints was evaluated. The scores of the single-leg jumping course test without any stabilizing device ("standard" category) ranged between 8.06 and 13.68 (10.65 + 1.29). In the Mikros (9.95 + 0.99) and Aircast (9.99 + 1.14) brace categories, as well as the tape bandage (10.27 + 0.81) category, better scores were achieved. The differences between "standard vs Mikros" and "standard vs Aircast" revealed a significant reduction of the scores with the orthoses (P < .01). The error rate in the single-leg stance test was within the range of 0 to 16 (5.12 + 2.85) for the standard category. It was lower for the Mikros (3.65 + 2.65) and Aircast (4.17 + 2.59) categories. The error rate was highest in the tape bandage group (5.79 + 3.53). There was a significant difference between "standard vs Mikros" and "standard vs Aircast" regarding injured and non-injured ankle joints (P < .01). The angle-reproduction test showed higher values for the standard (2.36 degrees + 0.97) category than the Mikros (1.46 degrees + 0.72), Aircast (1.62 degrees + 0.91), and taping (1.84 degrees + 0.41) categories. In the standard category, the reproduction error was lower when non-injured ankle joints (2.30 degrees + 1.04) were tested than when unstable ankle joints (2.44 degrees + 0.81) were tested, whereas in all other categories the reproduction error was higher in the group of non-injured joints. According to the literature, applying a prophylactic brace can prevent an estimated 30 ankle sprains per 1000 athletic exposures.

Proprioception and joint stability

In the present paper the current clinical knowledge about proprioception is given for the shoulder, knee, ankle, elbow and the radiocarpal joint. Proprioceptive capabilities are decreased after joint injuries such as ACL or meniscus tears, shoulder dislocation, ankle sprain and in joints with degenerative joint disease. Some surgical procedures seem to restore the proprioceptive abilities; others do not. Elastic knee bandages or ankle braces increase different proprioceptive factors like ankle reproduction capability or sports-specific abilities. The present information on proprioception will influence our clinical practice in the future. We should choose surgical procedures that not only reconstruct the anatomy, but also the neurophysiologic feed-back mechanism.

The influence of orthoses on the proprioception of the ankle joint

The ankle joints of 14 healthy volunteers and 16 patients with unstable ankle joints were tested regarding their functional and proprioceptive capabilities. All of them were active athletes. Three tests were used of the study: single-leg stance test, single-leg jumping course test, angle-reproduction test. The influence of three stabilization devices (lace-on-brace/"Mikros", stirrup-brace/"Aircast", taping) on the proprioceptivity of stable and unstable ankle joints was evaluated. The scores of the single-leg jumping course without any stabilizing device (category "standard") ranged between 8.06 and 13.68 (10.65 +/- 1.29). In the categories "Mikros" (9.85 +/- 0.99), and "Aircast" (9.99 +/- 1.14) as well as with the tape bandage (10.27 +/- 0.81) better scores were achieved. The differences "standard vs. Mikros" and "standard vs. Aircast" revealed a significant reduction of the scores with orthoses (P < 0.01). The error rate in the single-leg stance test was within the range of 0-16 (5.12 +/- 2.85) for the category "standard". It was lower for the categories "Mikros" (3.65 +/- 2.65) and "Aircast" (4.17 +/- 2.59). The error rate was highest in the group with a tape bandage (5.79 +/- 3.53). The differences "standard vs Mikros" as well as "standard vs. Aircast" were significant (P < 0.01). There was also a significant difference between these categories regarding injured and not injured ankle joints (P < 0.01). The angle-reproduction-test showed higher values for the category "standard" (2.36 degrees +/- 0.97) in comparison to the categories "Mikros" (1.46 degrees +/- 0.72), "Aircast" (1.62 degrees +/- 0.91) and "taping" (1.84 degrees +/- 0.41).(ABSTRACT TRUNCATED AT 250 WORDS)

A fivefold reduction in the incidence of recurrent ankle sprains in soccer players using the Sport-Stirrup orthosis

A study was undertaken to evaluate the effect of a semi-rigid ankle orthosis (Sport-Stirrup) on the incidence of ankle sprains in soccer players during 1 playing season. Senior soccer players were divided into 2 groups: players with previous ankle sprains (N = 258) and players without such history (N = 246). The players in these groups were each randomly allocated to either a semi-rigid orthosis or a control group at the start of the playing season. All subsequent injuries during the season and the total number of playing hours were documented. There was a significant reduction in the incidence of ankle sprains (injuries/1000 playing hours) by ankles in the orthosis group with previous sprains (0.14) compared with the nonbraced group with previous sprains (0.86). The incidence of ankle sprains was significantly higher in the nonbraced group with previous sprains (0.86) compared with the nonbraced group without previous sprains (0.46). Thus, in this study, a semirigid orthosis significantly reduced the incidence of recurrent ankle sprains in soccer players with previous history of ankle sprains.

Electromyographic response of peroneal muscles in surgical and nonsurgical injured ankles during sudden inversion

Because the peroneal muscles are thought to act as a safeguard against lateral ankle injury, it is important to study their function. This study was undertaken to electromyographically assess the latency between sudden unexpected ankle inversion and the start of peroneal muscle activity. Three groups participated in the study, including subjects with lateral ankle sprain rehabilitated nonsurgically (N = 7), sprains rehabilitated following surgery (N = 6), and injury-free ankles (N = 11). Peroneal latency was assessed by dropping the subjects into inversion from a special platform. The platform was designed so that either ankle could be inverted to 35 degrees without warning. The ANOVA revealed no significant latency differences (p > .05) between the three groups. The study suggests that bilateral peroneal latency is unaffected by injury. Although it has been thought that healthy muscles provide a defense against ankle sprain, their latency is not permanently affected by ankle injury or by surgery performed to correct defects from injury. It appears that mechanoreceptor impairment may be rehabilitated and that it is not a factor in ankle injury.

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.

Comparison of support provided by a semirigid orthosis and adhesive ankle taping before, during, and after exercise

The purpose of this study was to compare the relative effectiveness of athletic taping and a semirigid orthosis in providing inversion-eversion range restriction before, during, and after a 3 hour volleyball practice. The effect of each support method on the subjects' vertical jumping ability was also assessed. Fourteen ankles were treated with both methods of support. Passive inversion-eversion range of motion was measured on an ankle stability test instrument during five testing sessions: 1) before support, 2) before exercise, 3) 20 minutes during exercise, 4) 60 minutes during exercise, and 5) after exercise. The two-way analysis of variance and posthoc comparisons revealed maximal losses in taping restriction for both inversion and eversion at 20 minutes into exercise. The orthosis demonstrated no mechanical restrictive failure until before and after exercise comparisons were made, and then only eversion range of motion was compromised. Neither support system affected subjects' vertical jumping ability. These results suggest that the semirigid orthosis may be more effective than taping in providing initial ankle protection and in guarding against ligamentous reinjury.

Comparative study of functional bracing and plaster cast treatment of stable lateral malleolar fractures

In a prospective, randomized study, the use of the Aircast pneumatic air stirrup was compared with a standard below-knee walking cast in the management of Lauge-Hansen supination-eversion, stage II ankle fractures. Forty patients were randomly allocated to the two treatment groups. The use of the air stirrup led to a significant improvement in early patient comfort, post-fracture swelling, range of ankle motion at union, and time to full rehabilitation. We advocate the use of pneumatic air stirrup in the cost-effective management of stable ankle fractures.

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.