Prophylactic Ankle Taping and Bracing: A Numbers-Needed-to-Treat and Cost-Benefit Analysis

OBJECTIVE: Taping and bracing are thought to decrease the incidence of ankle sprains; however, few investigators have addressed the effect of preventive measures on the rate of ankle sprains. Our purpose was to examine the effectiveness of ankle taping and bracing in reducing ankle sprains by applying a numbers-needed-to-treat (NNT) analysis to previously published studies. DATA SOURCES: We searched PubMed, CINAHL, SPORT Discus, and PEDro for original research from 1966 to 2002 with key words ankle taping, ankle sprains, injury incidence, prevention, ankle bracing, ankle prophylaxis, andnumbers needed to treat. We eliminated articles that did not address the effects of ankle taping or bracing on ankle injury rates using an experimental design. DATA SYNTHESIS: The search produced 8 articles, of which 3 permitted calculation of NNT, which addresses the clinical usefulness of an intervention by providing estimates of the number of treatments needed to prevent 1 injury occurrence. In a study of collegiate intramural basketball players, the prevention of 1 ankle sprain required the taping of 26 athletes with a history of ankle sprain and 143 without a prior history. In a military academy intramural basketball program, prevention of 1 sprain required bracing of 18 athletes with a history of ankle sprain and 39 athletes with no history. A study of ankle bracing in competitive soccer players produced an NNT of 5 athletes with a history of previous sprain and 57 without a prior injury. A cost- benefit analysis of ankle taping versus bracing revealed taping to be approximately 3 times more expensive than bracing. CONCLUSIONS/RECOMMENDATIONS: Greater benefit is achieved in applying prophylactic ankle taping or bracing to athletes with a history of ankle sprain, compared with those without previous sprains. The generalizability of these results to other physically active populations is unknown.     

Lower extremity kinematics and ground reaction forces after prophylactic lace-up ankle bracing

CONTEXT: Long-term effects of ankle bracing on lower extremity kinematics and kinetics are unknown. Ankle motion restriction may negatively affect the body's ability to attenuate ground reaction forces (GRFs). OBJECTIVE: To evaluate the immediate and long-term effects of ankle bracing on lower extremity kinematics and GRFs during a jump landing. DESIGN: Experimental mixed model (2 [group] x 2 [brace] x 2 [time]) with repeated measures. SETTING: Sports medicine research laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 37 healthy subjects were assigned randomly to either the intervention (n = 11 men, 8 women; age = 19.63 +/- 0.72 years, height = 176.05 +/- 10.58 cm, mass = 71.50 +/- 13.15 kg) or control group (n = 11 men, 7 women; age = 19.94 +/- 1.44 years, height = 179.15 +/- 8.81 cm, mass = 74.10 +/- 10.33 kg). INTERVENTION(S): The intervention group wore braces on both ankles and the control group did not wear braces during all recreational activities for an 8-week period. MAIN OUTCOME MEASURE(S): Initial ground contact angles, maximum joint angles, time to reach maximum joint angles, and joint range of motion for sagittal-plane knee and ankle motion were measured during a jump-landing task. Peak vertical GRF and the time to reach peak vertical GRF were assessed also. RESULTS: While participants were wearing the brace, ankle plantar flexion at initial ground contact (brace = 35 degrees +/- 13 degrees , no brace = 38 degrees +/- 15 degrees , P = .024), maximum dorsiflexion (brace = 21 degrees +/- 7 degrees , no brace = 22 degrees +/- 6 degrees , P = .04), dorsiflexion range of motion (brace = 56 degrees +/- 14 degrees , no brace = 59 degrees +/- 16 degrees , P = .001), and knee flexion range of motion (brace = 79 degrees +/- 16 degrees , no brace = 82 degrees +/- 16 degrees , P = .036) decreased, whereas knee flexion at initial ground contact increased (brace = 12 degrees +/- 9 degrees , no brace = 9 degrees +/- 9 degrees , P = .0001). Wearing the brace for 8 weeks did not affect any of the outcome measures, and the brace caused no changes in vertical GRFs (P > .05). CONCLUSIONS: Although ankle sagittal-plane motion was restricted with the brace, knee flexion upon landing increased and peak vertical GRF did not change. The type of lace-up brace used in this study appeared to restrict ankle motion without increasing knee extension or vertical GRFs and without changing kinematics or kinetics over time.     

Factors Contributing to Chronic Ankle Instability: A Strength Perspective

OBJECTIVE: To examine the concept of dynamic ankle stability and closely critique the relevant research over the past 50+ years focusing on strength as it relates to those with chronic ankle instability (CAI). DATA SOURCES: We reviewed the literature regarding the assessment of strength related to CAI. We searched MEDLINE and ISI Web of Science from 1950 through 2001 using the key words functional ankle instability, chronic ankle instability, strength, ankle stability, chronic ankle dysfunction, and isokinetics. DATA SYNTHESIS: An overview of dynamic stability in the ankle is established, followed by a comprehensive discussion involving the variables used to assess ankle strength. Additionally, a historical look at deficits in muscular stability leading to CAI is provided, and a compilation of numerous contemporary approaches examining strength as it relates to CAI is presented. CONCLUSIONS/RECOMMENDATIONS: Although strength is an important consideration during ankle rehabilitation, deficits in ankle strength are not highly correlated with CAI. More contemporary approaches involving the examination of reciprocal muscle-group ratios as a measure of strength have recently been investigated and offer an insightful, albeit different, avenue for future exploration. Evidence pertaining to the effects of strength training on those afflicted with CAI is lacking, including what, if any, implication strength training has on the various measures of ankle strength.     

The effects of external support on electromechanical delay of the peroneus longus muscle

Ankle taping and bracing is commonly used in athletics and both have been shown to be effective in reducing injury. Ankle proprioception has been shown to increase with external support due to the activation of cutaneous mechanoreceptors, however, the sensorimotor effect has not been studied Electromechanical delay (EMD) is defined as the time lag from the onset of electrical activity in the muscle to the subsequent mechanical response. The purpose of this investigation was to measure and compare the EMD of the peroneus longus muscle during ankle unsupported, braced, and taped conditions. Thirty-one (10 male, 21female) healthy, college-aged subjects participated in the study (age: 20.9 +/- 1.8 years, mass 70.3 +/- 15.8 kg, height 171.1 +/- 9.6 cm). Each subject was assigned a random order for the three external support conditions. The subject was positioned on a force platform and instructed to actively evert the ankle. We examined the time lag between the onset of electrical activity in the peroneus longus muscle and a change in force as detected by the force platform. Five trials were completed for each condition and a repeated measures ANOVA was used to determine statistical significance. The results showed no significant difference between the three external support conditions. We concluded that external support through taping and bracing does not affect the EMD of the peroneus longus muscle in healthy subjects.     

Kinesthesia Is Not Affected by Functional Ankle Instability Status

OBJECTIVE: To determine whether subjects with functional ankle instability suffered kinesthetic deficits in the injured ankle compared with the healthy ankle and to examine the effect of prophylactic ankle bracing on kinesthesia in uninjured and functionally unstable ankles. DESIGN AND SETTING: We tested subjects over 4 consecutive days in a climate-controlled athletic training/sports medicine laboratory setting. A single-group time-series design enabled all subjects to serve as their own controls. A different bracing condition was tested on each of those occasions. SUBJECTS: Sixteen subjects (8 men, 8 women; age = 21.6 +/- 1.7 years; mass = 73.5 +/- 15.0 kg; height = 172.9 +/- 8.8 cm) with unilateral functional ankle instability participated in this study. MEASUREMENTS: Kinesthetic threshold-to-detection of passive motion (TTDPM) measurements were obtained during passive inversion and eversion movements (0.5 degrees.s(-1)) under 4 different bracing or taping conditions (unbraced, Swede-O Ankle Lok, Aircast Air-Stirrup, and tape). RESULTS: We analyzed the data using a 3-factor analysis of variance with repeated measures on the ankle and motion factors. Threshold-to-detection of passive motion scores in the unbraced condition were significantly better than the TTDPM scores in any of the other 3 test conditions. No significant differences were seen in TTDPM scores between the 2 ankles under any of the 4 conditions. CONCLUSIONS: Threshold-to-detection of passive motion scores did not differ in uninjured ankles and those with functional instability; however, bracing with either the Ankle Lok or Air-Stirrup decreased the ability to detect passive motion when compared with the no-tape (unbraced) condition. Further research is needed to determine the exact contributions of taping and bracing on ankle joint kinesthesia.     

Prophylactic ankle braces and knee varus-valgus and internal-external rotation torque

Context: Although prophylactic ankle bracing has been shown to be effective in reducing the incidence of ankle sprains,how these ankle braces might affect the other joints of the lower extremity is not clearly understood.Objective: To determine the effects of a prophylactic ankle brace on knee joint varus-valgus and internal-external rotation torque during a drop landing onto a slanted surface.Design: A repeated-measures design.Setting: Biomechanics research laboratory. Patients or Other Participants: Twenty-four physically active college students.Intervention(s): Participants were tested in a brace and no brace condition. Main Outcome Measure(s): We measured 3 dependent variables:(1) peak ankle inversion-eversion torque, (2) peak knee varus-valgus torque, and (3) peak knee internal-external rotation torque. A force plate was used to collect ground reaction force data, and 6 motion analysis cameras collected kinematic data during the unilateral drop landing. An adjustable bar was hung from the ceiling, and a slant board was positioned over the center of the force plate, so that the ankle of the participant's dominant leg would invert upon landing. Peak torque was measure din both the brace and no-brace conditions. The average of the peak values in 3 trials for both conditions was used for the statistical analysis.Results: Ankle eversion torque was significantly greater in the brace condition (F1,23 19.75, P < .01). Knee external rotation torque was significantly greater in the brace condition(F1,23 4.33, P <.05). Valgus knee torque was smaller in the brace condition, but the difference was not statistically significant(F1,23 3.45, P .08).Conclusions: This study provides an important first step in understanding the effects of prophylactic ankle bracing on other joints of the lower extremity. We found that prophylactic ankle bracing did have an effect on knee torque when the subject was landing on a slanted surface. Specifically, knee external rotation torque increased when the ankle was braced.     

Hip kinematics during a stop-jump task in patients with chronic ankle instability

Context:

Chronic ankle instability (CAI) commonly develops after lateral ankle sprain. Movement pattern differences at proximal joints may play a role in instability.

Objective:

To determine whether people with mechanical ankle instability (MAI) or functional ankle instability (FAI) exhibited different hip kinematics and kinetics during a stop-jump task compared with “copers.”

Design:

Cross-sectional study.

Setting:

Sports medicine research laboratory.

Patients or Other Participants:

Sixty-three recreational athletes, 21 (11 men, 10 women) per group, matched for sex, age, height, mass, and limb dominance. All participants reported a history of a moderate to severe ankle sprain. The participants with MAI and FAI reported 2 or more episodes of giving way at the ankle in the last year and decreased functional ability; copers did not. The MAI group demonstrated clinically positive anterior drawer and talar tilt tests, whereas the FAI group and copers did not.

Intervention(s):

Participants performed a maximum-speed approach run and a 2-legged stop jump followed by a maximum vertical jump.

Main Outcome Measure(s):

An electromagnetic tracking device synchronized with a force plate collected data during the stance phase of a 2-legged stop jump. Hip motion was measured from initial contact to takeoff into the vertical jump. Group differences in hip kinematics and kinetics were assessed.

Results:

The MAI group demonstrated greater hip flexion at initial contact and at maximum (P = .029 and P = .017, respectively) and greater hip external rotation at maximum (P = .035) than the coper group. The MAI group also demonstrated greater hip flexion displacement than both the FAI (P = .050) and coper groups (P = .006). No differences were noted between the FAI and coper groups in hip kinematic variables or among any of the groups in ground reaction force variables.

Conclusions:

The MAI group demonstrated different hip kinematics than the FAI and coper groups. Proximal joint motion may be affected by ankle joint function and laxity, and clinicians may need to assess proximal joints after repeated ankle sprains.     

鞋帮高度对跳跃动作踝关节矢状面运动学及动力学特征的影响

目的 探讨穿着高、低帮篮球鞋对跳跃动作踝关节矢状面运动学、动力学以及运动表现的影响。方法 利用Vicon运动捕捉系统和Kistler三维测力台同步采集12名受试者穿着高、低帮篮球鞋进行双腿落地反跳（drop jump, DJ）和单腿跨步跳（lay-up jump, LJ）过程中踝关节矢状面屈伸最小/最大角度、力矩、功率、刚度、跳跃高度以及背屈活动度等参数指标。结果 （1） 穿着高帮鞋能够显著减小踝关节的背屈角度（P<0.05）。在DJ和LJ过程中,两款鞋的跳跃高度、踝关节触地角度、最小/最大角度、活动度均无显著性差异;（2） 在DJ过程中,穿着两款鞋的踝关节屈伸动力学特征无显著差异;但在LJ过程中,穿着高帮鞋的跖屈力矩和功率峰值均显著小于低帮鞋（P<0.05）。结论 穿着高帮鞋虽然没有限制跳跃情况下踝关节的屈伸表现,但会影响踝关节矢状面的部分动力学特征,建议鞋帮高度的选择和设计能够在护踝的基础上充分发挥踝关节在矢状面的力学作用,从而实现运动表现的最优化。     

鞋帮高度对跳跃动作踝关节矢状面运动学及动力学特征的影响

目的探讨穿着高、低帮篮球鞋对跳跃动作踝关节矢状面运动学、动力学以及运动表现的影响。方法利用Vicon运动捕捉系统和Kistler三维测力台同步采集12名受试者穿着高、低帮篮球鞋进行双腿落地反跳(drop jump,DJ)和单腿跨步跳(lay-up jump,LJ)过程中踝关节矢状面屈伸最小/最大角度、力矩、功率、刚度、跳跃高度以及背屈活动度等参数指标。结果 (1)穿着高帮鞋能够显著减小踝关节的背屈角度(P0.05)。在DJ和LJ过程中,两款鞋的跳跃高度、踝关节触地角度、最小/最大角度、活动度均无显著性差异;(2)在DJ过程中,穿着两款鞋的踝关节屈伸动力学特征无显著差异;但在LJ过程中,穿着高帮鞋的跖屈力矩和功率峰值均显著小于低帮鞋(P0.05)。结论穿着高帮鞋虽然没有限制跳跃情况下踝关节的屈伸表现,但会影响踝关节矢状面的部分动力学特征,建议鞋帮高度的选择和设计能够在护踝的基础上充分发挥踝关节在矢状面的力学作用,从而实现运动表现的最优化。     

鞋帮高度对跳跃动作踝关节矢状面运动学及动力学特征的影响

目的 探讨穿着高、低帮篮球鞋对跳跃动作踝关节矢状面运动学、动力学以及运动表现的影响。方法 利用Vicon运动捕捉系统和Kistler三维测力台同步采集12名受试者穿着高、低帮篮球鞋进行双腿落地反跳（drop jump, DJ）和单腿跨步跳（lay-up jump, LJ）过程中踝关节矢状面屈伸最小/最大角度、力矩、功率、刚度、跳跃高度以及背屈活动度等参数指标。结果 （1） 穿着高帮鞋能够显著减小踝关节的背屈角度（P<0.05）。在DJ和LJ过程中,两款鞋的跳跃高度、踝关节触地角度、最小/最大角度、活动度均无显著性差异;（2） 在DJ过程中,穿着两款鞋的踝关节屈伸动力学特征无显著差异;但在LJ过程中,穿着高帮鞋的跖屈力矩和功率峰值均显著小于低帮鞋（P<0.05）。结论 穿着高帮鞋虽然没有限制跳跃情况下踝关节的屈伸表现,但会影响踝关节矢状面的部分动力学特征,建议鞋帮高度的选择和设计能够在护踝的基础上充分发挥踝关节在矢状面的力学作用,从而实现运动表现的最优化。     

Effects of Back-Support Exoskeleton Use on Lower Limb Joint Kinematics and Kinetics During Level Walking

We assessed the effects of using a passive back-support exoskeleton (BSE) on lower limb joint kinematics and kinetics during level walking. Twenty young, healthy participants completed level walking trials while wearing a BSE (backX^TM) with three different levels of hip-extension support torque (i.e., no torque, low, and high) and in a control condition (no-BSE). When hip extension torques were required for gait—initial 0–10% and final 75–100% of the gait cycle—the BSE with high supportive torque provided ~ 10 Nm of external hip extension torque at each hip, resulting in beneficial changes in participants’ gait patterns. Specifically, there was a ~ 10% reduction in muscle-generated hip extension torque and ~ 15–20% reduction in extensor power. During the stance-swing transition, however, BSE use produced undesirable changes in lower limb kinematics (e.g., 5–20% increase in ankle joint velocity) and kinetics (e.g., ~ 10% increase in hip flexor, knee extensor, and ankle plantarflexor powers). These latter changes likely stemmed from the need to increase mechanical energy for propelling the leg into the swing phase. BSE use may thus increase the metabolic cost of walking. Whether such use also leads to muscle fatigue and/or postural instability in long-distance walking needs to be confirmed in future work.

     

Surgical Considerations in the Treatment of Ankle Instability

OBJECTIVE: To review the surgical indications, techniques, biomechanical testing, and clinical results reported for the most common surgical techniques used to treat ankle instability. DATA SOURCES: We searched MEDLINE from 1960-2001 using the terms ankle instability, functional ankle instability, mechanical ankle instability, ankle ligament surgery, Brostr?m, Chrisman-Snook, and Evans. DATA SYNTHESIS: Although 80% to 85% of acute ankle sprains are successfully treated with a functional ankle-rehabilitation program, the remaining 15% to 20% have recurrent ankle instability and reinjury, necessitating surgical intervention. The fundamentals of the surgical approach to lateral ankle instability are based on the anatomy of the lateral ankle ligaments, the anterior talofibular ligament, and the calcaneofibular ligament. Ankle-instability surgery has been broadly divided into an anatomic repair consisting of an imbrication of the lateral ligamentous complex and an ankle-ligament reconstruction. An ankle-ligament reconstruction weaves a harvested tendon graft, most commonly the peroneus brevis, to augment the lateral ligaments of the ankle. Goals of surgery are to reestablish ankle stability and function without compromising motion and without complications. Anatomic repair and imbrication of the lateral ligament complex with the Gould modification has an 85% to 95% success rate, and the risk of associated nerve injuries is low. This approach provides increased stability by reinforcing local host tissue, preserving subtalar and talocrural motion, eliminating the comorbidity associated with tendon-graft harvest, and offering a quicker functional recovery. One concern in using the anatomic approach is the resultant strength of the repair, although the literature does not support this concern. Ankle-reconstruction procedures that sacrifice tendons are thought to provide a stronger construct, and hence, more stability. This increased stability results in loss of talocrural and subtalar range of motion, prolonging recovery and decreasing sport performance. Adjacent nerve injury is more common with ankle-ligament reconstruction. CONCLUSIONS/RECOMMENDATIONS: Based on the literature, we believe that a modified Brostr?m lateral-ligament repair should be considered the first choice for persistent ankle instability refractory to a functional ankle-rehabilitation protocol. Ankle reconstruction with tendon augmentation should be reserved for patients with generalized ligamentous laxity or long-standing ligamentous insufficiency or as a salvage procedure in a patient with a failed modified Brostr?m lateral-ligament repair.     

Dynamic Stabilization Time After Isokinetic and Functional Fatigue

OBJECTIVE: To compare the effects of an isokinetic fatigue protocol and a functional fatigue protocol on time to stabilization (TTS), ground reaction force (GRF), and joint kinematics during a jump landing. DESIGN AND SETTING: Subjects were assessed on 2 occasions for TTS, GRF, and joint kinematics immediately before and after completing a fatigue protocol. One week separated the 2 sessions, and the order of fatigue protocols was randomly assigned and counterbalanced. SUBJECTS: Twenty healthy male (n = 8, age = 21.8 +/- 1.4 years, height = 180.6 +/- 7.6 cm, and mass = 74.1 +/- 13.0 kg) and female (n = 12, age = 22.2 +/- 2.1 years, height = 169.3 +/- 9.8 cm, and mass = 62.5 +/- 10.1 kg) subjects volunteered to participate. MEASUREMENTS: Subjects performed 2-legged jumps equivalent to 50% of maximum jump height, followed by a single-leg landing onto the center of a forceplate 70 cm from the starting position. Peak vertical GRF and vertical, medial-lateral, and anterior-posterior TTS were obtained from forceplate recordings. Maximum ankle dorsiflexion, knee-flexion, and knee-valgum angles were determined using 3-dimensional motion analysis. RESULTS: A 2-way analysis of variance with repeated measures revealed no significant differences when comparing TTS, GRF, and joint kinematics after isokinetic and functional fatigue protocols. CONCLUSIONS: No difference was noted between isokinetic and functional fatigue protocols relative to dynamic stability when landing from a jump.     

Prophylactic ankle braces and star excursion balance measures in healthy volunteers

CONTEXT: The effects of prophylactic ankle braces on lower extremity functional performance in healthy participants have not been studied extensively. OBJECTIVE: To determine if prophylactic ankle braces affected multidirectional reach distances during a test of dynamic balance. DESIGN: Crossover. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-six healthy, physically active volunteers (18 men, 18 women; age = 23.6 +/- 2.7 years, height = 173.8 +/- 9.3 cm, mass = 74.4 +/- 12.7 kg, reach-leg length = 91.9 +/- 5.1 cm). INTERVENTION(S): Volunteers performed balance testing in 3 conditions: unbraced, while wearing a semirigid ankle brace, and while wearing a lace-up ankle brace. MAIN OUTCOME MEASURE(S): We used the Star Excursion Balance Test, calculating the mean of 3 attempts in 8 directions (anterior, anterior-medial, medial, posterior-medial, posterior, posterior-lateral, lateral, and anterior-lateral), normalized by the participant's reach-leg length. Data were collected after 6 practice attempts for each of the conditions according to a balanced Latin square. RESULTS: Bracing condition had no effect (P > .05) on any of the Star Excursion Balance Test directional measures. The largest mean difference due to bracing was 2.5% between the lace-up brace condition and the control in the posterior reach direction. This indicates that the actual reach differences due to bracing were less than 5.08 cm (2 inches) in length. CONCLUSIONS: Clinicians can be confident that the prophylactic use of ankle braces does not disrupt lower extremity dynamic balance during a reaching task in healthy participants.     

Biomechanical and Neuromuscular Effects of Ankle Taping and Bracing

OBJECTIVE: An extensive review of clinically relevant research is provided to assist clinicians in understanding the underlying mechanisms by which various ankle-support systems may provide beneficial effects. Strategies for management of different types of ankle ligament conditions are also discussed. BACKGROUND: Much of the literature pertaining to ankle instability and external support has focused on assessment of inward displacement of the hindfoot within the frontal plane. Some researchers have emphasized the importance of (1) pathologic rotary displacement of the talus within the transverse plane, (2) the frequent presence of subtalar joint ligament lesions, and (3) the interrelated effects of ankle support on deceleration of inversion velocity and facilitation of neuromuscular response. DESCRIPTION: The traditional method for application of adhesive tape to the ankle primarily restricts inward displacement of the hindfoot within the frontal plane. The biomechanical rationale for a method of ankle taping that restricts lower leg rotation and triplanar displacement of the foot associated with subtalar motion is presented. CLINICAL ADVANTAGES: The lateral subtalar-sling taping procedure may limit strain on the anterior talofibular ligament associated with subtalar inversion, restrain anterolateral rotary subluxation of the talus in the presence of ligament laxity, and protect the subtalar ligaments from excessive loading. The medial subtalar sling may reduce strain on the anterior-inferior tibiofibular syndesmosis and enhance hindfoot-to-forefoot force transfer during the push-off phase of the gait cycle.     

Modeling initial contact dynamics during ambulation with dynamic simulation

Ankle-foot orthoses are frequently used interventions to correct pathological gait. Their effects on the kinematics and kinetics of the proximal joints are of great interest when prescribing ankle-foot orthoses to specific patient groups. Mathematical Dynamic Model (MADYMO) is developed to simulate motor vehicle crash situations and analyze tissue injuries of the occupants based multibody dynamic theories. Joint kinetics output from an inverse model were perturbed and input to the forward model to examine the effects of changes in the internal sagittal ankle moment on knee and hip kinematics following heel strike. Increasing the internal ankle moment (augmentation, equivalent to gastroc-soleus contraction) produced less pronounced changes in kinematic results at the hip, knee and ankle than decreasing the moment (attenuation, equivalent to gastroc-soleus relaxation). Altering the internal ankle moment produced two distinctly different kinematic curve morphologies at the hip. Decreased internal ankle moments increased hip flexion, peaking at roughly 8% of the gait cycle. Increasing internal ankle moments decreased hip flexion to a lesser degree, and approached normal at the same point in the gait cycle. Increasing the internal ankle moment produced relatively small, well-behaved extension-biased kinematic results at the knee. Decreasing the internal ankle moment produced more substantial changes in knee kinematics towards flexion that increased with perturbation magnitude. Curve morphologies were similar to those at the hip. Immediately following heel strike, kinematic results at the ankle showed movement in the direction of the internal moment perturbation. Increased internal moments resulted in kinematic patterns that rapidly approach normal after initial differences. When the internal ankle moment was decreased, differences from normal were much greater and did not rapidly decrease. This study shows that MADYMO can be successfully applied to accomplish forward dynamic simulations, given kinetic inputs. Future applications include predicting muscle forces and decomposing external kinetics.     

负压引流联合内外固定治疗踝关节开放骨折脱位

目的探讨负压引流联合内外固定治疗踝关节开放骨折脱位可行性和疗效。方法选取23例开放性踝关节骨折的患者,急诊清创,并外固定架固定于功能位,VSD敷料覆盖创面后待二期行转移皮瓣修复创面。结果本组病例经过6~15月随访,无并发深部感染,优良率78%。结论对于开放性踝关节骨折、脱位,彻底清创结合负压引流技术,早期使用简单有效内外固定对骨折术后愈合及功能锻炼创造了条件。术后行踝关节功能锻炼,废用性骨质疏松可逐渐恢复,患者踝关节功能恢复满意。     

Effects of ankle braces upon agility course performance in high school athletes

The purpose of this study was to compare the effects of wearing the Aircast^TM Sports Stirrup, Aircast^TM Training brace, Swede-O^TM brace, and DonJoy^TM Ankle Ligament Protector while running an agility course. Eighty-five high school athletes with no history of ankle injury and no experience in wearing any ankle support served as subjects. Each subject participated in four separate testing sessions. During sessions 1 and 4, subjects ran the agility course under the control (unbraced) conditions. Sessions 2 and 3 consisted of randomly wearing the ankle braces while running the agility course. A questionnaire concerning support, comfort, and restriction was completed by each subject after wearing each of the braces. An analysis of variance (ANOVA) with repeated measures revealed that a significant difference existed between the agility times. Tukey's post hoc test indicated that a significant difference existed between each ankle brace and the control 2 agility times as well as a control 1 and control 2 time difference. The control time difference was attributed to a learning effect. An ANOVA with repeated measures of only the four braces revealed that a significant difference existed between the agility times. Tukey's post hoc test showed the only difference was between the DonJoy Ankle Ligament Protector and the Aircast Training brace. We concluded: 1) there is limited practical performance effect upon agility while wearing an ankle brace; and 2) an athlete's perceived comfort, support, and performance restriction are contributing factors that may directly influence the effectiveness of ankle bracing.     

The effects of self-reinnervation of cat medial and lateral gastrocnemius muscles on hindlimb kinematics in slope walking

The aim of this study was to investigate the effects of self-reinnervation of the medial (MG) and lateral gastrocnemius (LG) muscles on joint kinematics of the whole hindlimb during overground walking on surfaces of varying slope in the cat. Hindlimb kinematics were assessed (1) with little or no activity in MG and LG (short-term effects of self-reinnervation), and (2) after motor function of these muscles was presumably recovered but their proprioceptive feedback permanently disrupted (long-term effects of self-reinnervation). The stance phase was examined in three walking conditions: downslope (−50%, i.e. −26.6°), level (0%) and upslope (+50%, +26.6°). Measurements were performed prior to and at consecutive time points (between 1 and 57 weeks) after transecting and immediately suturing MG and LG nerves. It was found that MG-LG self-reinnervation did not significantly change hip height and hindlimb orientation in any of the three walking conditions. Substantial short-term effects were observed in the ankle joint (e.g., increased flexion in early stance) as well as in metatarsophalangeal and knee joints, leading to altered interjoint coordination. Hindlimb kinematics in level and upslope walking progressed back towards baseline within 14–19 weeks. Thus in these two conditions the cats were walking without any detectable kinematic deficits, despite the absence of length feedback from two major ankle extensors. This was verified in a decerebrate preparation for four of the five cats. In contrast, ankle joint kinematics as well as interjoint coordination in downslope walking gradually progressed towards, but never reached their baseline patterns. The short-term effects can be explained by both mechanical and neural factors that are affected by the functional elimination of MG and LG. Permanent changes in kinematics during downslope walking indicate the importance of proprioceptive feedback from the MG and LG muscles in regulating locomotor activity of ankle extensors. Full recovery of hindlimb kinematics during level and upslope walking suggests that the proprioceptive loss is compensated by other sensory sources (e.g. cutaneous receptors) or altered central drive.     

排球运动起跳过程中踝关节的生物力学特性

文题释义： 急停起跳：在激烈的排球比赛中,急停起跳动作是运动员比赛过程中出色完成扣球、拦网、跳发球、跳传球等技术所必不可少的关键阶段,也是运动员获得较好起跳高度的关键实施环节。 踝关节的活动范围：研究发现长期从事举重项目的人比正常人的踝关节活动度要小,长期从事游泳项目的人比正常人的踝关节活动度要大。踝关节的活动范围往往还跟运动成绩相关联,如短跑、速滑等竞速性项目运动成绩好的运动员踝关节的活动度也相对较好。 背景：目前对踝关节的生物力学特性研究多集中于方法学的探讨,对复合动作模式下踝关节生物力学特征的研究较少。 目的：分析对排球运动员起跳落地时踝关节的运动学和动力学特性。 方法：研究选取天津体育学院排球专项运动的学生男女各20名。主要采用Vicon三维运动捕捉系统和Kistler三维测力台,同步采集受试者在起跳落地时踝关节运动学与动力学参数,总共获得3次有效数据,利用统计学方法对数据进行对比分析。研究方案的实施符合天津体育学院的相关伦理要求,所有受试者均为自愿参加,并对试验过程完全知情同意。 结果与结论：①发现在该动作模式中,踝关节跖屈角度男性明显小于女性,在起跳阶段踝关节处于内翻和内旋状态,在落地缓冲阶段踝关节处于内翻和外旋状态,且角度男性组略大于女性,此时极易造成踝关节损伤;②三维方向的峰力矩和力值男性组均大于女性;三维方向峰值力矩和力出现的时间男性组晚于女性,而且存在双腿力量不均衡以及双脚不同时着地情况。 ORCID: 0000-0003-4584-148X(鲍春雨) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程