Ankle Devices Research Articles

Anthropomorphic Characterization of Ankle Joint.

Even though total ankle replacement has emerged as an alternative treatment to arthrodesis, the long-term clinical results are unsatisfactory. Proper design of the ankle device is required to achieve successful arthroplasty results. Therefore, a quantitative knowledge of the ankle joint is necessary. In this pilot study, imaging data of 22 subjects (with both females and males and across three age groups) was used to measure the morphological parameters of the ankle joint. A total of 40 measurements were collected by creating sections in the sagittal and coronal planes for the tibia and talus. Statistical analyses were performed to compare genders, age groups, and image acquisition techniques used to generate 3D models. About 13 measurements derived for parameters (TiAL, SRTi, TaAL, SRTa, TiW, TaW, and TTL) that are very critical for the implant design showed significant differences (p-value < 0.05) between males and females. Young adults showed a significant difference (p-value < 0.05) compared to adults for 15 measurements related to critical tibial and talus parameters (TiAL, TiW, TML, TaAL, SRTa, TaW, and TTL), but no significant differences were observed between young adults and older adults, and between adults and older adults for most of the parameters. A positive correlation (r > 0.70) was observed between tibial and talar width values and between the sagittal radius values. When compared with morphological parameters obtained in this study, the sizes of current total ankle replacement devices can only fit a very limited group of people in this study. This pilot study contributes to the comprehensive understanding of the effects of gender and age group on ankle joint morphology and the relationship between tibial and talus parameters that can be used to plan and design ankle devices.

Isolation and characterisation of wear debris surrounding failed total ankle replacements.

Aseptic loosening and osteolysis continue to be a short- to mid-term problem for total ankle replacement (TAR) devices. The production of wear particles may contribute to poor performance, but their characteristics are not well understood. This study aimed to determine the chemical composition, size and morphology of wear particles surrounding failed TARs. A recently developed wear particle isolation method capable of isolating both high- and low-density materials was applied to 20 retrieved periprosthetic tissue samples from 15 failed TARs of three different brands. Isolated particles were imaged using ultra-high-resolution imaging and characterised manually to determine their chemical composition, size, and morphology. Six different materials were identified, which included: UHMWPE, calcium phosphate (CaP), cobalt chromium alloy (CoCr), commercially pure titanium, titanium alloy and stainless steel. Eighteen of the 20 samples contained three or more different wear particle material types. In addition to sub-micron UHMWPE particles, which were present in all samples, elongated micron-sized shards of CaP and flakes of CoCr were commonly isolated from tissues surrounding AES TARs. The mixed particles identified in this study demonstrate the existence of a complex periprosthetic environment surrounding TAR devices. The presence of such particles suggests that early failure of devices may be due in part to the multifaceted biological cascade that ensues after particle release. This study could be used to support the validation of clinically-relevant wear simulator testing, pre-clinical assessment of fixation wear and biological response studies to improve the performance of next generation ankle replacement devices. STATEMENT OF SIGNIFICANCE: Total ankle replacement devices do not perform as well as total hip and knee replacements, which is in part due to the relatively poor scientific understanding of how they fail. The excessive production of certain types of wear debris is known to contribute to joint replacement failure. This is the first study to successfully isolate and characterise high- and low-density wear particles from tissues collected from patients with a failed total ankle replacement. This article includes the chemical composition and characteristics of the wear debris generated by ankle devices, all of which may affect their performance. This research provides clinically relevant reference values and images to support the development of pre-clinical testing for future total ankle replacement designs.

Assessment of Sleep Duration Based on Ankle and Wrist Actigraphy in Hospitalized Older Patients.

Poor sleep at time of hospitalization is associated with undesirable outcomes. Most studies performed in the hospital assess sleep by self-report, while only few rely on actigraphy. Although wrist actigraphy is commonly used for sleep assessment in field studies, in-hospital assessment may be challenging and cumbersome due to other more necessary monitoring devices that are often attached to patients’ upper limbs, that may in turn affect interpretation of wrist activity-data. Placement on the ankle may be a viable solution. In this pilot study, we aimed to compare total sleep time (TST) using concomitant wrist and ankle actigraphy as well as self-report. Twenty-one older adults (65+) hospitalized in medical units wore ankle and wrist actigraphy devices and subjectively estimated their TST for an average of (2.15±1.01) nights. A total of 45 nights were available for analysis. Average TST in minutes was 332.06±81.58, 427.05±97.74 and 374.28±124.96 based on wrist, ankle, and self-report, respectively. Repeated measure mixed models analysis was performed adjusting for age, gender, and sleep medications. TST was significantly lower using wrist compared to ankle actigraphy (F(2,102)=7.63, p=0.0008), and both were not different from self-report. No significant within subjects variation and no interaction between device and repeated measures were found. Despite differences between ankle and wrist assessments, all three provide consistent TST estimation within subjects. Self-report provides a stable and accessible assessment of TST, representing a good approximation of ankle and wrist actigraphy. Findings provide preliminary support for the use of ankle actigraphy for sleep assessment in hospital settings.

Predictive Simulation of Human Walking Augmented by a Powered Ankle Exoskeleton.

The human ankle provides significant positive power during the stance phase of walking, which has resulted in studies focusing on methods to reduce the energetic walking cost by augmenting the ankle with exoskeletons. Recently, a few devices have successfully reduced the metabolic cost of walking by replacing part of the biological ankle plantar flexor torque. Despite these achievements, development of assistive ankle devices remains challenging, partly because the current practice of design and control of powered exoskeletons is highly time and effort consuming, which prevents quickly exploring different design and control parameters. Predictive simulations using musculoskeletal models coupled with robotic devices may facilitate the process of design and control of assistive devices. In this study, we simulate human walking augmented by a powered ankle exoskeleton. The walking problem was formulated as a predictive dynamic optimization in which both the optimal assistive device torque and the gait were solved simultaneously. Cases with exoskeletons assisting one ankle and both ankles were considered. The results showed that the energetic cost of walking could be reduced by 45% with one ankle augmented, and by 52% with both ankles augmented. This study contributes towards the goal of providing optimal assistive torque through external devices and theoretical peak reductions that could be expected from such devices.

An Analysis of Foot and Ankle Device Recalls by the Food and Drug Administration.

IntroductionOrthopaedic devices represent 12% of all medical device recalls. Products are approved through pre-market approval (PMA) or the 510(k) premarket notification process. No previous evaluation was found in the literature evaluating foot and ankle device recalls. The field of foot and ankle subspecialty has seen a rapid growth in innovation related to implants in recent years.MethodsThe Food and Drug Administration (FDA) Device Recall database was evaluated for all foot and ankle devices from 2007 through 2017 for the manufacturer, process of approval, type of implant, recall class, dates of initiation and termination of the recall, manufacturer determined reason, quantity affected, and distribution within the United States or internationally.ResultsA total of 161 products from 33 companies were identified with 158 (98.1%) approved through the 510(k) process. The most common reason for device recall was due to the device breaking intraoperatively or postoperatively. The average length of the recall was 487.5 days. ConclusionsDevice recall is not an uncommon event with the majority of products approved through the less demanding 510(k) process.

Gait termination on a declined surface in trans-femoral amputees: Impact of using microprocessor-controlled limb system

BackgroundWalking down ramps is a demanding task for transfemoral-amputees and terminating gait on ramps is even more challenging because of the requirement to maintain a stable limb so that it can do the necessary negative mechanical work on the centre-of-mass in order to arrest (dissipate) forward/downward velocity. We determined how the use of a microprocessor-controlled limb system (simultaneous control over hydraulic resistances at ankle and knee) affected the negative mechanical work done by each limb when transfemoral-amputees terminated gait during ramp descent. MethodsEight transfemoral-amputees completed planned gait terminations (stopping on prosthesis) on a 5-degree ramp from slow and customary walking speeds, with the limb's microprocessor active or inactive. When active the limb operated in its ‘ramp-descent’ mode and when inactive the knee and ankle devices functioned at constant default levels. Negative limb work, determined as the integral of the negative mechanical (external) limb power during the braking phase, was compared across speeds and microprocessor conditions. FindingsNegative work done by each limb increased with speed (p < 0.001), and on the prosthetic limb it was greater when the microprocessor was active compared to inactive (p = 0.004). There was no change in work done across microprocessor conditions on the intact limb (p = 0.35). InterpretationGreater involvement of the prosthetic limb when the limb system was active indicates its ramp-descent mode effectively altered the hydraulic resistances at the ankle and knee. Findings highlight participants became more assured using their prosthetic limb to arrest centre-of-mass velocity.

Osteochondral autologous transplantation versus dorsal closing wedge metatarsal osteotomy for the treatment of Freiberg's infraction in athletes. Midterm results of a comparative study

The objectives of this study were to develop a clinically relevant in vitro elbow wear test and to compare the polyethylene wear of 2 total elbow replacement prostheses, one that uses conventional gamma-irradiated polyethylene (CPE) and one that uses vitamin E blended and cross-linked polyethylene (VE-HXPE) bushings.The test protocol applied 0° to 85° flexion-extension motions and imposed a constant 4.5° varus malalignment of the ulnar relative to the humeral implant under a variable joint load profile at a frequency of 1 Hz. The implants were tested for 3 million cycles (Mc) in a bovine serum lubricant at 37°C ± 3°C. Polyethylene wear was determined gravimetrically. Wear particles were isolated and characterized.Clinically relevant polyethylene bushings wear mechanisms were observed. After 3 Mc, the mean CPE wear rate was 9.3 ± 2.8 mm3/Mc, significantly lower than that reported for hip and knee implants but comparable to that of ankle (7.4 ± 1.3 mm3/Mc) devices. The mean VE-HXPE wear rate was 0.8 ± 0.2 mm3/Mc, comparable to that of hip and knees devices. The mean equivalent circle diameter and aspect ratio were 0.17 ± 0.01 µm and 1.99 ± 0.18 for the CPE and 0.15 ± 0.02 µm and 1.81 ± 0.16 for the VE-HXPE particles.The test replicated clinically observed failure modes for CPE devices. The use of VE-HXPE led to an order of magnitude reduction in polyethylene wear. Further clinical evaluation is necessary to determine if this translates into reduced complications of total elbow replacement associated with wear.

INVESTIGATING THE EFFECTS OF PASSIVE MECHANICAL ANKLE ON UNILATERAL OSTEOMYOPLASTIC TRANSTIBIAL AMPUTEES

Purpose The study presents an investigation of the asymmetries in normal gait associated with the use of prosthetic mechanical passive ankle devices when performing ambulatory-related activities for unilateral osteomyoplastic transtibial amputees. Asymmetries in gait may lead to low-back pain and other long-term effects associated with hip compensation and excessive energy consumption. Methods Unilateral transtibial osteomyoplastic amputees were tasked to perform normal gait. The Vicon Motion system and Myomotion System consisting of electromyography sensors and inertial measurement units were used to collect data. Quantitative gait analysis was used for the analysis of anatomical angles for the ankle, knee, hip and pelvis. The results were compared to normative data. Result It was hypothesized that the unilateral amputees would demonstrate high peaks on the hip, knee and ankle of the intact side so as to compensate for the lack of propulsive force on the passive ankle of the prosthetic limb. All parameters for anatomical angles were found to be significant ([Formula: see text]), hip flexion ([Formula: see text]), knee flexion ([Formula: see text]) and ankle dorsiflexion ([Formula: see text]). Temporal and distance variables were quantitatively analyzed and there was no significant difference. Poor management of range of motion was observed on the ankle and the knee. There was minimum hip extension during the stance phase. There was excessive hip rotation and foot plantarflexion on the intact side of the amputee as hip compensation was being applied during the toe-off period and early swing. Amputees exhibited short stance time duration. Conclusion This study demonstrated that amputees can achieve same distance variables as normal subjects; however, this causes variations in anatomical angles which result in asymmetries in normal gait. Variations in lateral pelvic tilt indicated possible development of lower back pain and changes in posture.

In vitro wear of ultrahigh-molecular-weight polyethylene and vitamin E blended highly cross-linked polyethylene in linked, semiconstrained total elbow replacement prostheses

The objectives of this study were to develop a clinically relevant in vitro elbow wear test and to compare the polyethylene wear of 2 total elbow replacement prostheses, one that uses conventional gamma-irradiated polyethylene (CPE) and one that uses vitamin E blended and cross-linked polyethylene (VE-HXPE) bushings. The test protocol applied 0° to 85° flexion-extension motions and imposed a constant 4.5° varus malalignment of the ulnar relative to the humeral implant under a variable joint load profile at a frequency of 1 Hz. The implants were tested for 3 million cycles (Mc) in a bovine serum lubricant at 37°C ± 3°C. Polyethylene wear was determined gravimetrically. Wear particles were isolated and characterized. Clinically relevant polyethylene bushings wear mechanisms were observed. After 3 Mc, the mean CPE wear rate was 9.3 ± 2.8 mm3/Mc, significantly lower than that reported for hip and knee implants but comparable to that of ankle (7.4 ± 1.3 mm3/Mc) devices. The mean VE-HXPE wear rate was 0.8 ± 0.2 mm3/Mc, comparable to that of hip and knees devices. The mean equivalent circle diameter and aspect ratio were 0.17 ± 0.01 µm and 1.99 ± 0.18 for the CPE and 0.15 ± 0.02 µm and 1.81 ± 0.16 for the VE-HXPE particles. The test replicated clinically observed failure modes for CPE devices. The use of VE-HXPE led to an order of magnitude reduction in polyethylene wear. Further clinical evaluation is necessary to determine if this translates into reduced complications of total elbow replacement associated with wear.

Corrosion Resistance and Mechanical Characterization of Ankle Prostheses Fabricated via Selective Laser Melting

This paper reports the results obtained in the evaluation of the corrosion resistance and mechanical characterization for SLM fabrication of endoprosthetic ankle devices. The corrosion behavior was monitored by recording the EIS spectra and polarization curves during 15 days of immersion in phosphate buffer saline (PBS) solution at pH 7.4 and pH 4, simulating the compositions of the body fluids under normal and inflammatory conditions, respectively. The surface of the samples was characterized with a scanning electron microscope coupled with an energy dispersive microanalysis (SEM/EDS). Finally, by considering mechanical resistance, corrosion resistance and manufacturing time, a differentiated process parameter strategy was proposed for bulk and surface fabrication.

Effects of foot and ankle devices on balance, gait and falls in adults with sensory perception loss: a systematic review.

EXECUTIVE SUMMARYBackgroundFoot and ankle devices are being developed as a method of preventing people with sensory perception loss sustaining a fall. Such devices are believed to work by reducing the likelihood of a fall by improving the balance and gait of the user.ObjectivesThe objective of the review was to evaluate the effectiveness of foot and ankle devices for the prevention of falls and the improvement of balance and gait in adults with sensory perception loss.Inclusion criteria Types of participantsParticipants were community-dwelling adults with bilateral pathological sensory perception loss.Types of intervention(s)/phenomena of interestThe current review evaluated any foot or ankle device, including but not restricted to, all types of footwear (therapeutic and retail), insoles (customized and prefabricated) and ankle-foot orthoses (AFOs).Types of studiesIn the absence of randomized controlled trials (RCT), the review considered experimental and epidemiological study designs, except case series, individual case reports and descriptive cross-sectional studies.OutcomesThe primary outcome was number of falls. Secondary outcome measures were clinical or laboratory measures of balance or gait.Search strategyA search for published and unpublished literature from inception to March 2015 written in the English language was conducted across a number of major electronic databases. A three-step search strategy was developed using MeSH terminology and keywords to ensure all that relevant materials are captured.Methodological qualityMethodological quality of included studies was assessed by two reviewers, who appraised each study independently, using standardized Joanna Briggs Institute (JBI) critical appraisal tools.Data extractionQuantitative data were extracted from the studies that were identified as meeting the criteria for methodological quality using the standardized JBI data extraction tools.Data synthesisDue to the heterogeneity of populations, interventions and outcome measures, meta-analyses were not possible and results are presented in narrative form.ResultsNine trials (from 10 papers) involving 238 participants, (14 with multiple sclerosis and 16 with idiopathic peripheral neuropathy, 150 with diabetic neuropathy) and 58 controls were included in the review. No study reported falls as an outcome measure. The results of the included studies found that in people with sensory perception loss, postural sway improved with vibrating insoles and AFO, altering the softness and texture of the top cover had no effect on postural sway, wearing footwear over long distances or AFOs improved step-to-step consistency, and no foot and ankle device was reported to have a negative effect on the balance or gait of people with sensory perception loss. The methodological quality of the included studies was poor. No study used a randomized controlled trial (RCT) methodology. No study incorporated a follow-up period or tested the intervention within the context of the intended clinical environment.ConclusionThere is limited evidence to suggest that footwear and insole devices can artificially alter postural stability and may reduce the step-to-step variability in adults with sensory perception loss. Varying the material properties of an insole does not notably affect static balance or gait.

Fabrication of Co–Cr–Mo endoprosthetic ankle devices by means of Selective Laser Melting (SLM)

A study of Cobalt–Chromium–Molybdenum endoprosthetic ankle implant fabrication by means of SLM is presented, including process characterization and kinematic considerations. Process optimization is first performed on samples with simple geometry to maximize density and mechanical strength using Co–Cr–Mo powders. Parameters such as laser scanning velocity, laser power and scanning strategy are varied, amongst others. Mechanical tests and microstructural analyses are performed to define process parameter windows for fabrication of near full density prostheses with negligible microstructural defects. Prosthetic ankles, based on medical imaging and biomechanical modeling, are then manufactured and kinematically tested to confirm their functional integrity and performance.

The effects of foot and ankle devices on balance, gait and falls in adults with sensory perception loss: a systematic review protocol

The effects of foot and ankle devices on balance, gait and falls in adults with sensory perception loss: a systematic review protocol

Kinematic comparison of walking on uneven ground using powered and unpowered prostheses

BackgroundRecent research has focused on the design of intelligent prosthetic ankle devices with the goal of adapting behavior of the device to accommodate all walking surfaces that an individual encounters in daily life. To date, no studies have looked at how such devices perform on uneven terrain. Methods11 young adults with unilateral transtibial amputation participated in two data collection sessions spaced approximately 3weeks apart. In each session they walked across a loose rock surface at three controlled speeds. In the first session, they wore a passive, energy storage and return prosthesis and in the second, they wore a powered prosthesis (BiOM, iWalk, Bedford, MA, USA). FindingsSubjects had a 10% faster self-selected walking speed when wearing the powered (1.16m/s) compared to unpowered prosthesis (1.05m/s; p=0.031). They walked with increased ankle plantarflexion on their prosthetic limb throughout the gait cycle when wearing the powered compared to unpowered prosthesis. This was especially evident in the increased plantarflexion during push-off (p<0.001). There was a small (<3°), but statistically significant decrease in knee flexion during early stance when wearing the powered device (p=0.045). Otherwise, the kinematics of the knee and hip were nearly identical when wearing the different devices. Subjects had decreased medial–lateral motion of their center of mass when wearing the powered prosthesis (p=0.020), but there were no differences in medial–lateral margins of stability between the devices (p=0.662). InterpretationSubjects did not significantly alter their proximal joint kinematics on this irregular surface as a result of the addition of power.

Passive Stability Characteristics of Ankle Braces and Tape in Simulated Barefoot and Shod Conditions

Background Ankle sprains are among the most common injuries in barefoot sport activities such as dance, gymnastics, or trampoline. At present, the use of external ankle devices for prevention of ligament injuries for barefoot activities remains unclear. Hypothesis External ankle devices have a significant loss of passive stability when used without a shoe in barefoot activities. Study Design Controlled laboratory study. Methods Twenty-five healthy subjects participated in the project (mean age, 26.2 ± 3.3 years; mean body mass, 71.2 ± 10.3 kg; mean height, 178 ± 7 cm). Passive range of motion measurements were performed with 3 different ankle stabilizers (a stirrup brace, a lace-up brace, and tape), as well as 2 different shoe conditions (cutout shoe [simulated barefoot] and normal shoe). Results In the simulated barefoot condition, a significantly reduced stabilizing effect for inversion and eversion (19% and 29%, respectively) was found for the stirrup ankle brace. Small decreases were noted with the soft brace and tape, but these were not statistically significant. Conclusion The passive stability characteristics of ankle braces depend to a great extent on being used in combination with a shoe. This is especially true for semirigid braces with stirrup design. Therefore, it is recommended that soft braces (like the one tested in the present investigation) be used in barefoot sports for restricting passive range of motion of the foot and ankle complex. Clinical Relevance This study provides useful information for clinicians to select or recommend an external ankle stabilizing device in barefoot sports to restrict passive range of motion of the foot-ankle complex most effectively.

Ground reaction force in basketball cutting maneuvers with and without ankle bracing and taping

In basketball, the most common injuries are ankle sprains. For this reason, players frequently use external ankle devices or taping as prophylactic and rehabilitation measures. The purpose of this study was to evaluate ground reaction force (GRF) responses in basketball players while performing typical cutting maneuvers with and without ankle bracing and ankle taping. Comparative study with experimental design of single-group repeated measurements, at Medical Rehabilitation Division, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo. Vertical (Fy) and medial-lateral (Fz) GRF measurements were made under three conditions (taping, Aircast-type orthosis and basketball shoes alone), with analysis of peak forces at foot contact (Fymax1, Fzmax1, Fymax2 and Fzmax2), growth gradient (peak/time) (GG Fymax1, GG Fzmax1, GG Fymax2 and GG Fzmax2) and impulse after foot contact. Bracing significantly reduced Fymax2 and GG Fymax2. GG Fzmax1 was significantly higher for the sport shoe condition than for the taping condition. Taping increased Fy in relation to the sport shoe at foot contact, but over a longer time interval, without increasing excessive ankle loading. Fz reached a peak in less time, which might generate greater inversion/eversion loading on a player's foot. The Aircast exerted better shock-absorbing effect than did the other two conditions, since it generated less vertical force over longer time intervals and smaller medial-lateral forces in relation to taping. Ankle bracing and ankle taping action mechanisms are still unclear and therefore should be carefully prescribed. More studies are needed to clarify taping and bracing effects on sporting activities.

Analysis of athletic performance with prophylactic ankle devices

We evaluated the effect of different ankle support devices on athletic performance. Thirty varsity college athletes were tested with both ankles supported by taping, Swede-O brace, Kallassy brace or left unsupported. The athletes performed four events: broad jump, vertical leap, 10 yard shuttle run, and 40 yard sprint. The events and appliances were randomized to prevent bias by fatigue. Compared to the results when no support was used, ankle taping resulted in a significant decreased performance in the vertical jump (4%), shuttle run (1.6%), and sprint (3.5%) (P less than 0.05). Use of the Swede-O brace decreased performance in the vertical jump (4.6%), broad jump (3.6%), and time of the sprint (3.2%). Results using the Kallassy brace showed a decrease in the vertical jump (3.4%) when compared to no support. The test results of the shuttle run with taping were slower than the Kallassy brace (P less than 0.05). Wearing the Swede-O brace caused the athletes' broad jump distance to decrease more than the Kallassy brace (P less than 0.05). Subjective questionnaires supported the Kallassy brace as the most comfortable support and the one that decreased performance the least. Taping of the ankles is universally accepted for ankle prophylaxis. This study has shown a decrease in performance when ankles are taped compared to ankles with no protection. Since the decreases in performance caused by ankle braces are minor, this should not be used as a criterion for selection of prophylactic support compared to taping.

Analysis of athletic performance with prophylactic ankle devices

We evaluated the effect of different ankle support devices on athletic performance. Thirty varsity college athletes were tested with both ankles supported by taping, Swede-O brace, Kallassy brace or left unsupported. The athletes performed four events: broad jump, vertical leap, 10 yard shuttle run, and 40 yard sprint. The events and appliances were randomized to prevent bias by fatigue. Compared to the results when no support was used, ankle taping resulted in a significant decreased performance in the vertical jump (4%), shuttle run (1.6%), and sprint (3.5%) (P less than 0.05). Use of the Swede-O brace decreased performance in the vertical jump (4.6%), broad jump (3.6%), and time of the sprint (3.2%). Results using the Kallassy brace showed a decrease in the vertical jump (3.4%) when compared to no support. The test results of the shuttle run with taping were slower than the Kallassy brace (P less than 0.05). Wearing the Swede-O brace caused the athletes' broad jump distance to decrease more than the Kallassy brace (P less than 0.05). Subjective questionnaires supported the Kallassy brace as the most comfortable support and the one that decreased performance the least. Taping of the ankles is universally accepted for ankle prophylaxis. This study has shown a decrease in performance when ankles are taped compared to ankles with no protection. Since the decreases in performance caused by ankle braces are minor, this should not be used as a criterion for selection of prophylactic support compared to taping.

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.