Mechanical Laxity Research Articles

Abnormal spinal cord motion at the craniocervical junction in hypermobile Ehlers-Danlos patients.

The craniocervical junction (CCJ) is anatomically complex and comprises multiple joints that allow for wide head and neck movements. The thecal sac must adjust to such movements. Accordingly, the thecal sac is not rigidly attached to the bony spinal canal but instead tethered by fibrous suspension ligaments, including myodural bridges (MDBs). The authors hypothesized that pathological spinal cord motion is due to the laxity of such suspension bands in patients with connective tissue disorders, e.g., hypermobile Ehlers-Danlos syndrome (EDS). The ultrastructure of MDBs that were intraoperatively harvested from patients with Chiari malformation was investigated with transmission electron microscopy, and 8 patients with EDS were compared with 8 patients without EDS. MRI was used to exclude patients with EDS and craniocervical instability (CCI). Real-time ultrasound was used to compare the spinal cord at C1-2 of 20 patients with EDS with those of 18 healthy control participants. The ultrastructural damage of the collagen fibrils of the MDBs was distinct in patients with EDS, indicating a pathological mechanical laxity. In patients with EDS, ultrasound revealed increased cardiac pulsatory motion and irregular displacement of the spinal cord during head movements. Laxity of spinal cord suspension ligaments and the associated spinal cord motion disorder are possible pathogenic factors for chronic neck pain and headache in patients with EDS but without radiologically proven CCI.

Hysteresis and stiffness of the lateral ankle complex in those with chronic ankle instability

ABSTRACT The role of mechanical laxity and viscoelastic tissue properties in chronic ankle instability (CAI) is unclear, but may influence repeated injury. The purpose was to determine if lateral ankle complex stiffness and hysteresis was altered in CAI individuals with and without mechanical laxity, compared to copers and uninjured controls. Thirty-five recreational athletes (19 females, 22.1 ± 2.7 years, 69.7 ± 15.7 kg, 168.4 ± 10.7 cm) were assessed for ankle injury history and self-reported instability. An instrumented arthrometer was applied and laxity, stiffness and hysteresis values were captured. Results from ANOVA tests indicated the CAI with laxity group had lower beginning- (3.2 ± 0.6 N/mm) and end-range stiffness (4.5 ± 0.4 N/mm) than the CAI without laxity group (4.7 ± 0.6; 6.0 ± 0.6 N/mm) and uninjured controls (4.6 ± 1.1; 5.8 ± 0.8 N/mm, p < 0.003). Hysteresis was greater in the CAI with laxity group than without laxity (91.0 ± 17.3 vs 62.8 ± 12.0 dN•mm; p = 0.03). Altered tissue properties in a CAI with laxity group likely indicate diminished ability of the lateral ankle complex to respond to loading. Accurately assessing, then avoiding or restoring tissue impairments after injury, may encourage better patient outcomes.

Identifying Range-of-Motion Deficits and Talocrural Joint Laxity After an Acute Lateral Ankle Sprain.

Approximately 72% of patients with an ankle sprain report residual symptoms 6 to 18 months later. Although 44% of patients return to activity in less than 24 hours after experiencing a sprain, residual symptoms should be evaluated in the long term to determine if deficits exist. These residual symptoms may be due to the quality of ligament tissue and motion after injury. To compare mechanical laxity of the talocrural joint and dorsiflexion range of motion (DFROM) over time (24 to 72 hours, 2 to 4 weeks, and 6 months) after an acute lateral ankle sprain (LAS). Cross-sectional study. Athletic training research laboratory. A total of 108 volunteers were recruited. Fifty-five participants had an acute LAS and 53 participants were control individuals without a history of LAS. Mechanical laxity (talofibular interval and anterior talofibular ligament length) was measured in inversion (INV) and via the anterior drawer test. The weight-bearing lunge test was conducted and DFROM was measured. The data were analyzed using repeated-measures analysis of variance, independent-samples t tests, and 1-way analysis of variance. Of the 55 LASs, 21 (38%) were grade I, 27 (49%) were grade II, and 7 (13%) were grade III. Increases were noted in DFROM over time, between 24 and 72 hours, at 2 to 4 weeks, and at 6 months (P < .05). The DFROM was less in participants with grade III than grade I LASs (P = .004) at 24 to 72 hours; INV length was greater at 24 to 72 hours than at 2 to 4 weeks (P = .023) and at 6 months (P = .035) than at 24 to 72 hours. The anterior drawer length (P = .001) and INV talofibular interval (P = .004) were greater in the LAS group than in the control group at 6 months. Differences in range of motion and laxity were evident among grades at various time points and may indicate different clinical responses after an LAS.

Evaluation modalities for the anatomical repair of chronic ankle instability.

Several evaluation modalities are reported in the literature dealing with the operative treatment of chronic ankle instability (CAI) both to establish the CAI diagnosis leading to the surgical indication and to assess the effectiveness of ankle stabilisation procedure. The purpose of this study is to present an overview of the pre- and postoperative evaluation modalities reported in the literature dealing with CAI operative treatment. The comprehensive analysis of the different modalities chosen by researchers is expected to suggest critical points in current evaluation ability of CAI surgical treatment. Systematic review of the literature on surgical treatment of CAI through anatomic procedures. Pubmed, Embase and Cochrane electronic databases were analysed, from 2004 to 2018. One-hundred-and-four studies met inclusion in this systematic review. 88 out of 104 studies analysed preoperative mechanical laxity of the ankle to depict the ligamentous insufficiency related to the subjective feeling of functional instability. Stress radiographs and manual stress examination of the ankle were the two most common modalities to evaluate joint laxity, reported in 67 and 53 studies, respectively. Clinical Outcome Measurement Scales (COMs) is the most common evaluation modality (102 out of 104 studies) to assess CAI surgical outcome. The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale (AOFAS) and the Karlsson score are the most frequent COMs, reported in the 66% and 33%, respectively of the included literature. The radiographic analysis of ankle laxity after stabilisation procedures is the second most frequent postoperative evaluation modality, reported in 55 out 104 studies. There is a lack of standardization among researchers related to both the criteria to establish the CAI diagnosis leading to the surgical indication and the modality chosen to evaluate the effectiveness of surgical treatment. Future standardization of evaluation modalities in the CAI population is desirable to increase consistency of reported data. Level IV, review of level I, II, III and IV studies.

Do External Supports Improve Dynamic Balance in Patients with Chronic Ankle Instability? A Network Meta-analysis.

To improve ankle stability in patients who have experienced an ankle sprain with residual symptoms of instability and/or objective joint laxity, external supports (such as taping, bracing, and orthotic insoles) are used sometimes. However, available randomized trials have disagreed on whether restraints improve balance in those individuals. In this situation, a network meta-analysis can help because it allows for comparing multiple treatments simultaneously, taking advantage not only of direct but also indirect evidence synthesis. The aim of this network meta-analysis was to assess (1) the impact of taping and orthotic devices on dynamic postural control in individuals with ankle instability and (2) the presence of a placebo effect in participants treated with sham taping and complications resulting from the administered treatments. We searched the PubMed, Scopus, and CENTRAL databases up to February 13, 2019 for completed studies. Randomized trials assessing the results of real and/or sham taping, wait-and-see protocols, ankle bracing, and foot orthotics for ankle instability as determined by one or more ankle sprains followed by ongoing subjective symptoms and/or mechanical laxity were included. We evaluated dynamic postural control in terms of the Star Excursion Balance Test in the posteromedial direction (SEBT-PM), which is considered the most representative of balance deficits in patients with ankle instability. Standardized mean differences were re-expressed to percentage differences in SEBT-PM, with higher scores representing possible improvement. Subsequently, those data were checked against the established minimal detectable change of 14% for this scale to make judgements on clinical importance. We also assessed the presence of a placebo effect by comparing the results of sham taping with no treatment and complications resulting from the administered treatments. Additionally, we judged the quality of trials using the Cochrane risk of bias tool and quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. A total of 22 trials met our inclusion criteria, 18 of which were deemed to be at a low risk of bias. A network of treatments consisting of 13 studies was created, and the level of evidence was judged to be high. As far as participants' allocation to treatment arms, 85 patients followed a wait-and-see protocol, 29 received placebo taping, 99 were treated with taping, 16 were treated with bracing, 27 were administered insoles, and six individuals were offered a combination of insoles with bracing. Of note, with statistical power set at 80%, a minimum of 16 patients per treatment group was required to provide sufficient statistical power and detect a SEBT-PM percentage difference of 14%. A network meta-analysis did not demonstrate a benefit of taping or bracing over no treatment (percentage difference in SEBT-PM between taping and bracing versus control: -2.4 [95% CI -6 to 1.1]; p = 0.18, and -7.5 [95% CI -15.9 to 1]; p = 0.08, respectively). This was also the case for sham taping because the measurement increase failed to exceed the minimal detectable change (percentage difference in SEBT-PM between sham taping and untreated control: -1.1 [95% CI -6.9 to 4.7]; p = 0.72). Importantly, there were no reported adverse events after treatment application. Evidence of moderate strength indicated that external supports of any type were no more effective than controls in improving dynamic postural control in patients with at least one ankle sprain and residual functional or mechanical deficits. Therefore, implementing those tools as a standalone treatment does not appear to be a viable strategy for the primary management of ankle instability. It is conceivable that combinations of rehabilitation and external supports could be more effective than external supports alone, and future trials should evaluate the potential of such combinations in enhancing not only clinician-reported but also patient-oriented outcomes using long-term follow-up measurements. Level I, therapeutic study.

Individuals with Recurrent Ankle Sprain Demonstrate Postural Instability and Neuromuscular Control Deficits in Unaffected Side

Category:Ankle, SportsIntroduction/Purpose:To compare proprioception, postural stability, and neuromuscular control between patients with mechanical laxity and recurrent ankle sprain.Methods:Among 86 patients with ankle instability, 45 patients had mechanical laxity (mean age 27.2 ± 7.0 years) and 41 had recurrent ankle sprain (mean age 25.1 ± 9.2 years). Both the affected and unaffected ankles of each patient were evalu- ated. Proprioception and neuromuscular control tests were conducted using an isokinetic machine, and postural stability was tested using a postural stabilometry system.Results:Proprioception was not significantly different between the unaffected or affected ankles of the mechanical laxity group compared with those of the recurrent ankle sprain group (n.s). Static and dynamic postural stability and neuromus- cular control were similar in the affected ankles between the two groups (n.s). However, postural stability (static, overall: p = 0.009, anterior– posterior: p = 0.028, medial–lateral: p = 0.022; dynamic, overall: p = 0.012, anterior–posterior: p = 0.004, medial–lateral: p = 0.001) and neuromuscular control (inversion: p = 0.031, eversion: p = 0.039, dorsiflexion: p = 0.029, plantarflexion: p = 0.035) were significantly decreased in the unaffected ankles of the recurrent ankle sprain group compared with those of the mechanical laxity group.Conclusion:The unaffected ankles of the recurrent ankle sprain group showed significant decreases in both postural stability and neuromuscular control compared with the mechanical laxity group. Clinicians and therapists should consider unaffected ankle rehabilitation in patients with recurrent ankle sprain to prevent future sprain events.

Ankle Strength Deficits in a Cohort of College Athletes With Chronic Ankle Instability.

Lateral ankle sprains commonly occur in an athletic population and can lead to chronic ankle instability. To compare ankle strength measurements in athletes who have mechanical laxity and report functional instability after a history of unilateral ankle sprains. Retrospective cohort. Athletic Training Research Lab. A total of 165 National Collegiate Athletic Association Division I athletes, 97 males and 68 females, with history of unilateral ankle sprains participated. Functional ankle instability was determined by Cumberland Ankle Instability Tool scores and mechanical ankle instability by the participant having both anterior and inversion/eversion laxity. Peak torque strength measures, concentric and eccentric, in 2 velocities were measured. Of the 165 participants, 24 subjects had both anterior and inversion/eversion laxity and 74 self-reported functional ankle instability on their injured ankle. The mechanical ankle instability group presented with significantly lower plantar flexion concentric strength at 30°/s (139.7 [43.7]N·m) (P = .01) and eversion concentric strength at 120°/s (14.8 [5.3]N·m) (P = .03) than the contralateral, uninjured ankle (166.3 [56.8]N·m, 17.4 [6.2]N·m, respectively). College athletes who present with mechanical laxity on a previously injured ankle exhibit plantar flexion and eversion strength deficits between ankles.

Individuals with recurrent ankle sprain demonstrate postural instability and neuromuscular control deficits in unaffected side

To compare proprioception, postural stability, and neuromuscular control between patients with mechanical laxity and recurrent ankle sprain. Among 86 patients with ankle instability, 45 patients had mechanical laxity (mean age 27.2 ± 7.0years) and 41 had recurrent ankle sprain (mean age 25.1 ± 9.2years). Both the affected and unaffected ankles of each patient were evaluated. Proprioception and neuromuscular control tests were conducted using an isokinetic machine, and postural stability was tested using a postural stabilometry system. Proprioception was not significantly different between the unaffected or affected ankles of the mechanical laxity group compared with those of the recurrent ankle sprain group (n.s). Static and dynamic postural stability and neuromuscular control were similar in the affected ankles between the two groups (n.s). However, postural stability (static, overall: p = 0.009, anterior-posterior: p = 0.028, medial-lateral: p = 0.022; dynamic, overall: p = 0.012, anterior-posterior: p = 0.004, medial-lateral: p = 0.001) and neuromuscular control (inversion: p = 0.031, eversion: p = 0.039, dorsiflexion: p = 0.029, plantarflexion: p = 0.035) were significantly decreased in the unaffected ankles of the recurrent ankle sprain group compared with those of the mechanical laxity group. The unaffected ankles of the recurrent ankle sprain group showed significant decreases in both postural stability and neuromuscular control compared with the mechanical laxity group. Clinicians and therapists should consider unaffected ankle rehabilitation in patients with recurrent ankle sprain to prevent future sprain events. Case-control study, III.

Influence of Prophylactic Ankle Tapes on Lower Extremity Kinematics during Stop-jump in Chronic Ankle Instability

Nuremous tape applications have been used with patients who suffer from chronic ankle instability (CAI). The goal is to control the increased mechanical laxity associated with their condition during dynamic activity. The effect of these prophylactic ankle tapings on lower extremity kinematics has not been fully identified at this time. PURPOSE: To investigate the effects of traditional tape (TT), fibular repositioning tape (FRT), and kinesiology tape (KT) on peak joint angles of the lower extremity in individuals with CAI. METHODS: 14 individuals with CAI (age: 24.07±4.46 years; height: 175.06±5.09 cm; weight: 82.24± 10.38 kg; CAIT = 17.64 ± 4.14; FAAM-ADL = 86.69 ± 6.71; FAAM-SS = 75.45 ± 6.70) participated in the study. The Foot and Ankle Ability Measure Activity of Daily Living (FAAM-ADL), the FAAM Sports Subscale (FAAM-SS), and the Cumberland Ankle Instability Tool (CAIT) were used to screen subjects for CAI. The order of application of the taping conditions (TT, FRT, and KT) was randomly assigned. Peak angles of the hip, knee, and ankle joint during a stop-jump task, with and without the tape application, were collected using a 3D motion capture system. The following peak angles were measured: hip flexion (Flex), hip adduction (ADD), hip internal rotation (IR), knee Flex, knee abduction (ABD), knee IR, ankle dorsiflexion (DF), ankle inversion (IV), and ankle ADD. To examine differences across the conditions (Baseline, TT, FRT, KT), a repeated measures ANOVA was performed. RESULTS: A statistically significant difference in peak angle of each joint across the conditions was not found (hip Flex.: F(3,39) = .85, p = .47; hip ADD: F(3,39) = 1.90, p = .15; hip IR: F(3,39) = .67, p = .58; knee Flex.: F(3,39) = 1.85, p = .15; knee ABD: F(3,39) = 1.02, p = .39; knee IR: F(3,39) = .44, p = .73; ankle DF: F(3,39) = .66, p = .58; ankle IV: F(3,39) = 0.85, p = .47; ankle ADD: F(3,39) = 2.23, p = .10). CONCLUSION: The application of different taping techniques did not significantly change peak joint angles of the lower extremity during a stop-jump task. The results contradict previous research suggesting ankle taping restricts joint range of motion. Therefore, further investigation is needed to examine the influence of different prophylactic ankle taping techniques on sports performance, as well as muscle activation, during dynamic tasks.

Individuals with both perceived ankle instability and mechanical laxity demonstrate dynamic postural stability deficits

BackgroundChronic ankle instability is a frequent and serious consequence of lateral ankle sprains. The contribution of perceived instability and potential for mechanical laxity to contribute to the overall deficit in dynamic postural stability is unclear. The purpose was to determine if those with mechanical laxity demonstrated significant differences in dynamic postural stability compared to controls, copers and those with perceived instability. MethodsOf 93 participants, 83 recreationally active individuals were divided into 4 groups: controls, copers, those with perceived instability, and those with both perceived instability and mechanical laxity. Injury history and the Cumberland Ankle Instability Tool were collected, and an instrumented arthrometer was applied. Participants completed a single limb jump landing, balancing upon completion. Ground reaction force data were collected, scaled to body mass, and the Dynamic Postural Stability Indices were calculated for anterior–posterior, medial–lateral, vertical and composite. One-way ANOVAs with Tukey post-hoc tests (α<0.05) were conducted on each of the stability indices among the four groups. FindingsThe mechanically lax group had significantly greater mean (standard deviation) medial–lateral stability index scores 0.57 (0.62) than the coper group 0.24 (0.20; P=0.02) and significantly greater composite index scores 0.73 (0.57) than the perceived instability 0.49 (0.09) and coper groups 0.47 (0.12 P=0.05). No other indices were significantly different among groups. InterpretationIndividuals with perceived instability and mechanical laxity exhibited dynamic postural deficits compared to copers and those with perceived instability alone. Mechanical laxity may contribute to the deficits in dynamic postural stability.

Can balance training affect the ankle joint stiffness in subjects with unilateral chronic ankle instability?

Background: Lateral ankle sprain is one of the most frequent sports-related injuries, accounting for up to 60% of all athletic injuries. The development of repetitive ankle sprains and persistent residual symptoms such as repeated episodes of ankle giving way, pain, weakness, loss of function, and feeling of ankle instability after injury has been termed chronic ankle instability (CAI). The signs and symptoms of initial injury often resolve with time but mechanical joint laxity may last longer leading to residual symptoms. Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with CAI but the biomechanical and/or neurophysiological pathways underlying the clinical outcomes are still unknown. Balance training is routinely used in clinical practice for sprained ankles, however to our knowledge, only one study has examined the effects of balance training intervention on flexibility characteristics of the ankle joint in patients with CAI. Purpose: This study was conducted to determine if a 4week balance training intervention can alter the mechanical characteristics in ankles with CAI. Methods: Twenty-two recreationally active subjects with unilateral CAI were randomized to either a control (n= 11, 35.1± 9.3 years) or intervention (n= 11, 33.5± 6.6 years) group. Subjects in the intervention group were trained on the affected limb with static and dynamic components using a Biodex balance stability system for 4-weeks. The ankle joint stiffness and neutral zone in inversion and eversion directions on the involved and uninvolved limbs was measured at baseline and post-intervention using a dynamometer. Results:Atbaseline, themeanvalues of the inversion stiffness (0.69± 0.37Nm/degree) in the involved ankle was significantly lower (p< 0.011, 95% CI [0.563, 0.544]) than that of uninvolved contralateral ankle (0.99± 0.41Nm/degree). With the available sample size, the eversion stiffness, inversion neutral zone, and eversion neutral zone were not found to be significantly different between the involved and uninvolved contralateral ankles. The 4-week balance training intervention failed to show any significant effect on the passive ankle stiffness and neutral zones in inversion and eversion. Conclusion(s): Decreased inversion stiffness in the involved chronic unstable ankle was found that of uninvolved contralateral ankle. The 4-week balance training program intervention was ineffective in altering the mechanical characteristics of ankles with CAI. Implications:Traditionally, taping and bracing have been used to improve stability and prevent recurrent ankle injury in patients with CAI. However, the beneficial effects of ankle taping have been attributed to enhanced proprioception and mechanical restriction, but there is no indication of restoring ligamentous stability. Further research with additional stiffness measures along with functional tests, larger sample size, and progressive balance training exercises is needed to identify if the mechanical characteristics of chronic unstable ankles can be altered.

Minimum Reporting Standards for Copers in Chronic Ankle Instability Research

Lateral ankle sprains (LASs) are among the most common sports-related injuries and a high percentage of individuals who sprain their ankle go on to develop chronic ankle instability (CAI). The condition of CAI is often classified as having pain, loss of function, and a restriction of, or failure to, return to levels of previous activity. Historically, uninjured healthy controls are used as a comparison group to study the biomechanical and neuromuscular consequences of CAI. However, this model is not ideal to determine why a portion of the population experiencing an ankle sprain does not recover. A more appropriate comparison may be individuals who had an ankle sprain, and thus the exposure, but did not go on to develop CAI (i.e., copers). Thus, the purpose of this review was to determine the existing discrepancies and common standards in definitions of, terminology used for, and the inclusionary/exclusionary criteria used to describe copers within the CAI literature. Multiple databases were searched by keywords and specific authors. Potential studies were screened independently by both authors. Inclusion criteria consisted of an explicit definition of copers and explicit inclusionary/exclusionary criteria. A total of 21 studies were included in the current study and had four outcomes extracted: (1) the definition of copers; (2) the terminology used; (3) specific inclusionary/exclusionary criteria; and (4) injury characteristics of the copers. Based on the included operational definitions, it is recommend that future operational definitions of copers include three key components: (1) an initial LAS; (2) subsequent lack of CAI symptoms (i.e., no complaints of disability or giving way); and (3) a time since injury component. The term coper was overwhelming used within the existing literature (n = 15) and is thus recommended to be used in future studies when describing individuals who have suffered an LAS but failed to develop CAI. Minimal inclusionary criteria should consist of three things: (1) an initial LAS severe enough to warrant either the use of a protective device (e.g., ankle brace) for at least 1 week or immobilization and/or non-weight bearing for at least 3 days, or both; (2) a return to at least moderate levels of weight-bearing physical activity for at least 12 months without recurrent injury, episodes of giving way, and/or feelings of instability; and (3) minimal, if any, level of self-reported disability. Acute head and/or lower extremity injuries that occurred ≤3 months prior to testing, a history of ankle fractures and/or surgeries, and the presence of pain (constant or intermittent) should be used as minimal exclusionary criteria in future investigations dealing with copers. Finally, at least seven items should be reported to better contextualize copers across investigations. These items should include the initial mechanism of injury, the presence of mechanical laxity, number of days immobilized and/or non-weight bearing after the initial ankle sprain, time since the latest ankle sprain, percentage of coper participants with a recurrent ankle sprain or giving way episode, current physical activity levels, and whether copers attended formal rehabilitation for their involved ankle.

Avaliação do torque de resistência passiva em atletas femininas com entorse de tornozelo

INTRODUÇÃO: A entorse de tornozelo é uma das lesões mais comuns em atletas. Uma forma de avaliar a frouxidão ligamentar pode ser através da medida da amplitude passiva dos movimentos de inversão e eversão do pé para estimar a resistência passiva das estruturas capsuloligamentares do tornozelo, o qual pode ser chamado de torque de resistência passiva. Existem poucos estudos que utilizam a avaliação do torque passivo do tornozelo para avaliar a resistência da cápsula e dos ligamentos. OBJETIVO: O objetivo deste estudo foi comparar o torque passivo dos movimentos de inversão e eversão do pé em atletas com e sem história de entorse de tornozelo. MÉTODO: Participaram do estudo 32 atletas de basquetebol e voleibol feminino (16,06 ± 0,8 anos, 67,63 ± 8,17kg, 177,8 ± 6,47cm). Seus tornozelos foram divididos em dois grupos: grupo controle (29), composto por tornozelos sem sintomas, e grupo entorse de tornozelo, composto por tornozelos que sofreram lesão (29). O torque dos movimentos passivos do tornozelo foi registrado por um dinamômetro isocinético, e a atividade dos músculos fibular longo e tibial anterior foi medida por um eletromiógrafo. As atletas realizaram duas repetições do movimento de inversão e eversão, nas velocidades de 5, 10 e 20°/s e, em seguida, o mesmo protocolo foi repetido apenas para o movimento de inversão máxima do pé. RESULTADOS: O torque de resistência passiva durante os movimentos de inversão e eversão do pé foi menor no grupo com entorse do tornozelo. Este grupo também mostrou menor torque durante o movimento de inversão máxima do pé. Não foram observadas diferenças entre o movimento de inversão e eversão. CONCLUSÕES: A entorse de tornozelo leva a um menor torque de resistência passiva, indicando redução da resistência dos ligamentos colaterais do tornozelo e uma frouxidão articular mecânica.

Differences in Lateral Ankle Laxity Measured via Stress Ultrasonography in Individuals With Chronic Ankle Instability, Ankle Sprain Copers, and Healthy Individuals

Cross-sectional. To use stress ultrasonography to measure the change in anterior talofibular ligament length during the simulated anterior drawer and ankle inversion stress tests. In approximately 30% of individuals, ankle sprains may eventually develop into chronic ankle instability (CAI) with recurrent symptoms. Individuals with CAI and those who have a history of ankle sprain (greater than 1 year prior) without chronic instability (copers) may or may not have mechanical laxity. Sixty subjects (n=60 ankles) were divided into 3 groups: 1) Control subjects without ankle injury history (n=20; mean ± SD age; 24.8 ± 4.8 years; height, 173.7 ± 9.4 cm; weight, 77.2 ± 19.5 kg), ankle sprain copers (n=20; 22.3 ± 2.9 years; 172.8 ± 11.3 cm; 72.4 ± 14.3 kg), and subjects with CAI (n=20; 23.5 ± 4.2 years; 174.6 ± 9.6 cm; 74.8 ± 17.3 kg). Ligament length change with the anterior drawer and end range ankle inversion was calculated from ultrasound images. The Foot and Ankle Ability Measure (FAAM) was used to quantify self-reported function on activities-of-daily living (ADL) and sports. The anterior drawer test resulted in length changes that were greater (F₂,₅₇=6.2, P=.004) in the CAI (mean ± SD length change, 15.6 ± 15.1%, P=.006) and the coper groups (14.0 ± 15.9%, P=.016) compared to the control group (1.3 ± 10.7%); however the length change for the CAI and coper groups were not different (P=.93). Ankle inversion similarly resulted in greater ligament length change (F₂,₅₇=6.5, P=.003) in the CAI (25.3 ± 15.5%, P=.003) and coper groups (20.2 ± 19.6%, P=.039) compared to the control group (7.4 ± 12.9%); with no difference in length change between the copers and CAI groups (P=.59). The CAI group had a lower score on the FAAM-ADL (87.4 ± 13.4%) and FAAM-Sports (74.2 ± 17.8%) when compared to the control (98.8 ± 2.9% and 98.9 ± 3.1%, P<.0001) and coper groups (99.4 ± 1.8% and 94.6 ± 8.8%, P<.0001). Stress ultrasonography identified greater length changes of the anterior talofibular ligament in both the coper and CAI groups compared to the control group. Only subjects with CAI had reductions in self-reported function.

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Effect of Ankle Taping on Mechanical Laxity in Chronic Ankle Instability

The high percentage of re-injury after an initial ankle sprain necessitates examination of preventative methods. The purpose of this project was to investigate the effect ankle tape has on mechanical laxity in subjects with CAI. Twenty subjects with unilateral CAI (seven males and 13 females; age, 20.6 +/- 1.8 years; mass, 69.9 +/- 13.7 kg; height, 172.3 +/- 9.3 cm) and 20 healthy subjects (seven males and 13 females; age, 21.9 +/- 4.3 years; mass, 72.0 +/- 14.6 kg; height, 171.1 +/- 6.7 cm) participated in the study. Both ankles of each subject were tested under two conditions: 1) before the application of tape; and 2) immediately after 30 minutes of exercise with the ankle taped. Mechanical laxity was measured with an instrumented ankle arthrometer. Two (group) x two (time) repeated measures ANOVA analysis was used for analysis. There were significant group by time interactions (p = 0.014) for anterior displacement with significantly increased anterior displacement in the involved ankle of the CAI group relative to the matched control limb both before and after tape application. Similarly, there were significant time main effects for posterior displacement (p = 0.004), inversion (p = 0.001) and eversion (p = 0.043) rotation. Specifically, tape application decreased posterior displacement, inversion and eversion rotation only in the CAI group. Additionally, a significant group main effect for inversion rotation (p = 0.001) was also noted. Followup testing indicated significantly greater inversion rotation for the CAI ankle compared to the matched healthy ankle before tape application. Mechanical laxity significantly decreased in CAI subjects after tape application. Although there was still a significant difference in mechanical laxity between the involved ankle vs. the uninvolved ankle of the CAI group, as well as the matched healthy group, laxity decreased in the CAI ankle after the application of tape. Ankle taping may be able to improve mechanical instability in those with CAI.

Mechanical Instability After an Acute Lateral Ankle Sprain

Hubbard TJ, Cordova M. Mechanical instability after an acute lateral ankle sprain. Objective To examine the natural recovery of mechanical laxity after an ankle sprain over an 8-week period. Design Prospective cohort study. Setting Biodynamics research laboratory. Participants Subjects with an acute lateral ankle sprain (n=16; 7 men, 9 women; age, 19.5±0.7y; mass, 64.6±8.1kg; height, 171.9±9.6cm) and healthy controls (n=16; 7 men, 9 women; age, 20.4±1.7y; mass, 76.9±11.1kg; height, 176.5±11.1cm) participated. Interventions Not applicable. Main Outcome Measures Subjects with acute ankle sprains were tested 3 days after injury and again 8 weeks later. Anterior and posterior displacement (mm) and inversion and eversion rotation (°) were measured with an instrumented arthrometer. For each dependent variable, a 2 × 2 × 2 repeated-measures multivariate analysis of variance was performed. Results A significant interaction was found between group, time, and side for anterior translation (F=4.24, P=.05). There were also significant main effects for group. There was significantly more anterior displacement at day 3 (F=19.52, P=.001) and at week 8 (F=8.45, P=.010) in the injured group compared with the healthy group. There was also significantly more inversion rotation at day 3 (F=2.70, P=.002) and at week 8 (F=5.4, P=.033) in the injured group compared with the healthy group. Conclusions The lack of significant differences in mechanical laxity over an 8-week period suggests that natural recovery of laxity takes longer than 8 weeks. Further research needs to be conducted to examine how long this laxity persists and the role ankle rehabilitation plays in mechanical stability restoration.

Ankle Ligament Healing After an Acute Ankle Sprain: An Evidence-Based Approach

To perform a systematic review to determine the healing time of the lateral ankle ligaments after an acute ankle sprain. We identified English-language research studies from 1964 to 2007 by searching MEDLINE, Physiotherapy Evidence Database (PEDro), SportDiscus, and CINAHL using the terms ankle sprain, ankle rehabilitation, ankle injury, ligament healing, and immobilization. We selected studies that described randomized, controlled clinical trials measuring ligament laxity either objectively or subjectively immediately after injury and at least 1 more time after injury. Two reviewers independently scored the 7 studies that met the inclusion criteria. Because of differences in study designs, a meta-analysis could not be performed. Effect sizes and confidence intervals could be calculated only for 1 study. The percentages of subjective and objective instability were calculated for the remaining studies. Ankle laxity improved over a period of 6 weeks to 1 year. One author showed stress talar tilt values of 16.10 +/- 8.8 degrees immediately after injury and 3.4 +/- 3.6 degrees at 3 months after injury. In 2 articles, the authors reported that positive anterior drawer tests were still present in 3% to 31% of participants at 6 months after injury. Additionally, feelings of instability affected 7% to 42% of participants up to 1 year after injury. In the studies that we examined, it took at least 6 weeks to 3 months before ligament healing occurred. However, at 6 weeks to 1 year after injury, a large percentage of participants still had objective mechanical laxity and subjective ankle instability. Direct comparison among articles is difficult because of differences in methods. More research focusing on more reliable methods of measuring ankle laxity is needed so that clinicians can know how long ligament healing takes after injury. This knowledge will help clinicians to make better decisions during rehabilitation and for return to play.

Arthroscopic Capsular Shrinkage for Chronic Ankle Instability with Thermal Radiofrequency: Prospective Multicenter Trial

The study was designed as a prospective multicenter longitudinal trial. Adult patients with symptomatic mechanical chronic ankle instability, not improving with conservative therapy, were included and underwent surgery. Primary outcome measures were radiological and manually tested mechanical laxity. Secondary outcome measures were number of complications, reoperations and symptoms, range of motion, and functional (ankle) scores (Karlsson and SF-36 score). The latest follow-up was 9 months for each patient. Thirty-nine patients underwent surgery (19 male patients; 16 right ankles; median age, 27 years). Mechanical stability showed no clinically relevant improvement whereas most secondary outcome measures showed a substantial and statistically significant improvement. One surgery-related complication occurred without functional consequences, and 3 patients underwent a secondary procedure. One was considered a treatment failure, requiring an open anatomic ligament reconstruction. The second patient sustained a severe supination trauma by starting intensive training too early, also requiring an open anatomic reconstruction. The third patient had posterior ankle pain, which was successfully treated by posterior ankle arthroscopy. Arthroscopic thermal capsular shrinkage of the ankle is a safe procedure, leading to resolution of symptoms in the majority of patients with chronic ankle instability.

Arthroscopic Capsular Shrinkage for Chronic Ankle Instability with Thermal Radiofrequency: Prospective Multicenter Trial

The study was designed as a prospective multicenter longitudinal trial. Adult patients with symptomatic mechanical chronic ankle instability, not improving with conservative therapy, were included and underwent surgery. Primary outcome measures were radiological and manually tested mechanical laxity. Secondary outcome measures were number of complications, reoperations and symptoms, range of motion, and functional (ankle) scores (Karlsson and SF-36 score). The latest follow-up was 9 months for each patient. Thirty-nine patients underwent surgery (19 male patients; 16 right ankles; median age, 27 years). Mechanical stability showed no clinically relevant improvement whereas most secondary outcome measures showed a substantial and statistically significant improvement. One surgery-related complication occurred without functional consequences, and 3 patients underwent a secondary procedure. One was considered a treatment failure, requiring an open anatomic ligament reconstruction. The second patient sustained a severe supination trauma by starting intensive training too early, also requiring an open anatomic reconstruction. The third patient had posterior ankle pain, which was successfully treated by posterior ankle arthroscopy. Arthroscopic thermal capsular shrinkage of the ankle is a safe procedure, leading to resolution of symptoms in the majority of patients with chronic ankle instability.