Single-leg drop landing movement strategies 6 months following first-time acute lateral ankle sprain injury

Absorption function loss due to the history of previous ankle sprain explored by unsupervised machine learning

BACKGROUND

Ankle sprains are common and cause persistent ankle function reduction. To biomechanically evaluate the ankle function after ankle sprains, the ground reaction force (GRF) measurement during the single-legged landing had been used. However, previous studies focused on discrete features of vertical GRF (vGRF), which largely ignored vGRF waveform features that could better identify the ankle function.

PURPOSE

To identify how the history of ankle sprain affect the vGRF waveform during the single-legged landing with unsupervised machine learning considering the time-series information of vGRF.

METHODS

Eighty-seven currently healthy basketball athletes (12 athletes without ankle sprain, 49 athletes with bilateral, and 26 athletes with unilateral ankle sprain more than 6 months before the test day) performed single-legged landings from a 20 centimeters (cm) high box onto the force platform. Totally 518 trials vGRF data were collected from 87 athletes of 174 ankles, including 259 ankle sprain trials (from previous sprain ankles) and 259 non-ankle sprain trials (from without sprain ankles). The first 100 milliseconds (ms) vGRF waveforms after landing were extracted. Principal component analysis (PCA) was applied to the vGRF data, selecting 8 principal components (PCs) representing 96% of the information. Based on these 8 PCs, k-means method (k = 3) clustered the 518 trials into three clusters. Chi-square test assessed significant differences (p < 0.01) in the distribution of ankle sprain and non-ankle sprain trials among clusters.

FINDINGS

The ankle sprain trials accounted for a significantly larger percentage (63.9%) in Cluster 3, which exhibited rapidly increased impulse vGRF waveforms with larger peaks in a short time.

SIGNIFICANCE

PCA and k-means method for vGRF waveforms during single-legged landing identified that the history of previous ankle sprains caused a loss of ankle absorption ability lasting at least 6 months from an ankle sprain.

Effect of Hamstring Tightness and Fatigue on Dynamic Stability and Agility in Physically Active Young Men

Hamstring extensibility has been defined as a factor to diminished dynamic stability and therefore increased risk of injury. The purpose of this study was to analyse the effects of hamstring tightness and fatigue on dynamic stability and agility. Nineteen participants were divided between the normal extensibility group (NEG) (n = 9, 82.2° ± 12.4°) and hamstrings tightness group (HTG) (n = 10, 64° ± 4.9°) using the passive straight leg raise test. To analyse dynamic stability and agility, they performed the modified Star Excursion Balance Test (mSEBT) and Dynamic Postural Stability Index (DPSI), and hexagon agility test, respectively, before and after a fatigue protocol. A two-way repeated measures ANOVA was used to determine differences among conditions: NEG vs. HTG, and rested vs. fatigued. HTG showed a significantly lower reach in the anterior direction in the mSEBT in pre- and post-fatigue than NEG. Participants in the NEG showed poor stability after landing in the mediolateral direction on DPSI post-fatigue. No significant changes were found in agility related with the group nor fatigue state. Participants with hamstring extensibility reduction has no differences in dynamic stability after landing nor agility after fatigue test, but significantly affects reaching distances during one-leg balance. As a conclusion, a reduction in range of motion in HTG was observed, but no other effects were observed on performance and dynamic stability after a local fatigue protocol depending on hamstring extensibility.

The Influence of Therapeutic Exercise after Ankle Sprain on the Incidence of Subsequent Knee, Hip, and Lumbar Spine Injury

PURPOSE

This study aimed to investigate the burden of knee, hip, and lumbar spine disorders occurring in the year after an ankle sprain and the influence therapeutic exercise (TE) has on this burden.

METHODS

A total of 33,361 individuals diagnosed with ankle sprain in the Military Health System between 2010 and 2011 were followed for 1 yr. The prevalence of knee, hip, and lumbar care-seeking injuries sustained after sprain was identified. Relationships between demographic groups, ankle sprain type, and use of TE with rate of proximal injuries were evaluated using Cox proportional hazard models to determine hazard rate effect modification by attribute. The observed effect of TE for ankle sprain on rate of injury to proximal joints was evaluated using Kaplan-Meier survival analyses.

RESULTS

Of the total cohort, 20.5% ( n = 6848) of patients sustained a proximal injury. Specifically, 10.1% of the cohort sustained a knee ( n = 3356), 2.9% a hip ( n = 973), and 10.3% a lumbar injury ( n = 3452). Less than half of the cohort received TE after initial sprain. Patients that did were less likely to have subsequent knee (HR = 0.87, 95% confidence interval [CI] = 0.80-0.94), hip (HR = 0.68, 95% CI = 0.58-0.79), or lumbar (HR = 0.82, 95% CI = 0.76-0.89) injuries.

CONCLUSIONS

One in five individuals that sought care for an ankle sprain experienced a proximal joint injury in the following year. TE for the management of the initial ankle sprain reduced the likelihood of proximal injury diagnosis and should be considered in treatment plans for return to work and sport protocols after ankle sprains.

How Common is Subsequent Posterior Tibial Tendon Dysfunction or Tarsal Tunnel Syndrome After Ankle Sprain Injury?

Posterior tibial tendon dysfunction (PTTD) and tarsal tunnel syndrome (TTS) are debilitating conditions reported to occur after ankle sprain due to their proximity to the ankle complex. The objective of this study was to investigate the incidence of PTTD and TTS in the 2 years following an ankle sprain and which variables are associated with its onset. In total, 22,966 individuals in the Military Health System diagnosed with ankle sprain between 2010 and 2011 were followed for 2 years. The incidence of PTTD and TTS after ankle sprain was identified. Binary logistic regression was used to identify potential demographic or medical history factors associated with PTTD or TTS. In total, 617 (2.7%) received a PTTD diagnosis and 127 (0.6%) received a TTS diagnosis. Active-duty status (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.70-2.79), increasing age (OR 1.03, 95% CI 1.02-1.04), female sex (OR 1.58, 95% CI 1.28-1.95), and if the sprain location was specified by the diagnosis (versus unspecified location) and did not include a fracture contributed to significantly higher (p < 0.001) risk of developing PTTD. Greater age (OR 1.06, 95% CI 1.03-1.09), female sex (OR 2.73, 95% CI 1.74-4.29), history of metabolic syndrome (OR 1.73, 95% CI 1.03-2.89), and active-duty status (OR 2.28, 95% CI 1.38-3.77) also significantly increased the odds of developing TTS, while sustaining a concurrent ankle fracture with the initial ankle sprain (OR 0.45, 95% CI 0.28-0.70) significantly decreased the odds. PTTD and TTS were not common after ankle sprain. However, they still merit consideration as postinjury sequelae, especially in patients with persistent symptoms. Increasing age, type of sprain, female sex, metabolic syndrome, and active-duty status were all significantly associated with the development of one or both subsequent injuries. This work provides normative data for incidence rates of these subsequent injuries and can help increase awareness of these conditions, leading to improved management of refractory ankle sprain injuries.

Influence of Landing in Neuromuscular Control and Ground Reaction Force with Ankle Instability: A Narrative Review

Ankle sprains are generally the most common injuries that are frequently experienced by competitive athletes. Ankle sprains, which are the main cause of ankle instability, can impair long-term sports performance and cause chronic ankle instability (CAI). Thus, a comprehensive understanding of the key factors involved in repeated ankle strains is necessary. During jumping and landing, adaptation to the landing force and control of neuromuscular activation is crucial in maintaining ankle stability. Ankle mobility provides a buffer during landing, and peroneus longus activation inhibits ankle inversion; together, they can effectively minimize the risk of ankle inversion injuries. Accordingly, this study recommends that ankle mobility should be enhanced through active and passive stretching and muscle recruitment training of the peroneus longus muscles for landing strategies should be performed to improve proprioception, which would in turn prevent ankle sprain and injury to neighboring joints.

Acceleration and Jerk After a Jump Stabilization Task in Individuals With and Without Chronic Ankle Instability

Studies have demonstrated that individuals with chronic ankle instability (CAI) have diminished dynamic stability. Jerk-based measures have been utilized to examine dynamic balance because of their ability to quantify changes in acceleration and may provide an understanding of the postural corrections that occur during stabilizing following a jumping task. The purpose of this study was to compare acceleration and jerk following a jump stabilization task between individuals with CAI and the uninjured controls. Thirty-nine participants volunteered to participate in this case control study. Participants completed a jump stabilization task requiring them to jump off 2 feet, touch a marker set at 50% of their maximal vertical jump height, land on a single limb, and maintain balance for 3 seconds. Acceleration was calculated as the second derivative, and jerk was calculated as the third derivative of the displacement of the resultant vector position. Participants with CAI had greater acceleration (mean difference = 55.6 cm/s2; 95% confidence interval, 10.3 to 100.90; P = .017) and jerk compared with the uninjured controls (mean difference = 1804.5 cm/s3; 95% confidence interval, 98.7 to 3510.3; P = .039). These results suggest that individuals with CAI made faster and more frequent active postural control corrections to regain balance following a jump compared with the uninjured controls.

Lower extremity joint kinematics of a simulated lateral ankle sprain after drop landings in participants with chronic ankle instability

This study examined lower extremity joint kinematics in individuals with chronic ankle instability (CAI) and controls during unanticipated and anticipated single-leg drop landings onto a laterally inclined platform. Physically active adults with CAI 15 (n = 15) and controls (n = 15) performed an unanticipated and anticipated 30 cm single-leg drop landing onto a 20° laterally inclined platform. Three-dimensional ankle, knee and hip-joint kinematics were recorded 200 ms pre- to 200 post-landing and analysed with a 2 (group) × 2 (landing condition) SPM ANOVA (p < 0.05). Results revealed individuals with CAI displayed significantly greater ankle internal rotation post-landing across both landing conditions. Anticipated landings elicited significantly greater pre-landing ankle inversion and external rotation, knee abduction and hip adduction. Additionally, significantly less ankle inversion, knee and hip flexion, and knee adduction and hip abduction were present during post-landing of the anticipated landing. Greater ankle internal rotation during landing may contribute to the ankle 'giving way' in individuals with CAI. However, preparatory and reactive proximal-joint kinematics were similar in both groups during landing. This highlights the possible role of the knee and hip joints in assisting with ankle-joint stability during anticipated inversion perturbations.

Ankle Stability and Movement Coordination Impairments: Lateral Ankle Ligament Sprains Revision 2021

This revised clinical practice guideline (CPG) addresses the distinct but related lower extremity impairments of those with a first-time lateral ankle sprain (LAS) and those with chronic ankle instability (CAI). Depending on many factors, impairments may continue following injury. While most individuals experience resolution of symptoms, complaints of instability may continue and are defined as CAI. The aims of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. J Orthop Sports Phys Ther 2021;51(4):CPG1-CPG80. doi:10.2519/jospt.2021.0302.

Effect of finding-oriented manual therapy techniques on muscle activity and postural control in patients with chronic ankle instability - A randomized controlled feasibility study

INTRODUCTION

Previous studies have analyzed the effects of manual therapy techniques (MTT) in patients with chronic ankle instability (CAI). Clinicians treat patients according the finding-oriented MTT approach. This approach is seldom pursued in research. The purpose of this study was to evaluate the feasibility and efficacy of finding-oriented MTT applications in patients with CAI.

METHOD

In this randomized controlled, blinded assessor crossover feasibility trial, participants were randomized to receive nine finding-oriented MTT treatments or no treatment during a three-week period, followed by a six-day washout period after which participants were crossed-over. Criteria under evaluation were adherence and attrition rates, safety (adverse events (AEs)) and acceptability and preliminary effects of finding-oriented MTT on muscular activity (measured by surface Electromyography (sEMG)) and on dynamic balance (measured by time to stabilization (TTS) and the modified Star Excursion Balance Test (modified STBT)).

RESULTS

Seven women and two men (mean age: 26 ± 6.1 years) with CAI enrolled in this feasibility study. Success criteria showed a high adherence (90%) and low attrition rate (10%). All data could be used for analysis. AEs such as tingling in the foot during a short time frame were reported after four finding-oriented MTT interventions. Preliminary effect sizes showed divergence and few statistically significant results for sEMG.

CONCLUSION

The participants were adherent to the finding-oriented MTT intervention. The acceptability of data recording and data analysis was good. In addition, the study protocol should be adapted by adding a 10-min warm up period, a participant familiarization to TTS and modified STBT, and test repetitions.

Biomechanical Response to External Biofeedback During Functional Tasks in Individuals With Chronic Ankle Instability

CONTEXT

Altered biomechanics displayed by individuals with chronic ankle instability (CAI) is a possible cause of recurring injuries and posttraumatic osteoarthritis. Current interventions are unable to modify aberrant biomechanics, leading to research efforts to determine if real-time external biofeedback can result in changes.

OBJECTIVE

To determine the real-time effects of visual and auditory biofeedback on functional-task biomechanics in individuals with CAI.

DESIGN

Crossover study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Nineteen physically active adults with CAI (7 men, 12 women; age = 23.95 ± 5.52 years, height = 168.87 ± 6.94 cm, mass = 74.74 ± 15.41 kg).

INTERVENTION(S)

Participants randomly performed single-limb static balance, step downs, lateral hops, and forward lunges during a baseline and 2 biofeedback conditions. Visual biofeedback was given through a crossline laser secured to the dorsum of the foot. Auditory biofeedback was given through a pressure sensor placed under the lateral foot and connected to a buzzer that elicited a noise when pressure exceeded the set threshold. Cues provided during the biofeedback conditions were used to promote proper biomechanics during each task.

MAIN OUTCOME MEASURE(S)

We measured the location of center-of-pressure (COP) data points during balance with eyes open and eyes closed for each condition. Plantar pressure in the lateral column of the foot during functional tasks was extracted. Secondary outcomes of interest were COP area and velocity, time to boundary during static balance, and additional plantar-pressure measures.

RESULTS

Both biofeedback conditions reduced COP in the anterolateral quadrant while increasing COP in the posteromedial quadrant of the foot during eyes-open balance. Visual biofeedback increased lateral heel pressure and the lateral heel and midfoot pressure-time integral during hops. The auditory condition produced similar changes during the eyes-closed trials. Auditory biofeedback increased heel pressure during step downs and decreased the lateral forefoot pressure-time integral during lunges.

CONCLUSIONS

Real-time improvements in balance strategies were observed during both external biofeedback conditions. Visual and auditory biofeedback appeared to effectively moderate different functional-task biomechanics.

The effect of chronic ankle instability on muscle activations in lower extremities

BACKGROUND/PURPOSE

Muscular reflex responses of the lower extremities to sudden gait disturbances are related to postural stability and injury risk. Chronic ankle instability (CAI) has shown to affect activities related to the distal leg muscles while walking. Its effects on proximal muscle activities of the leg, both for the injured- (IN) and uninjured-side (NON), remain unclear. Therefore, the aim was to compare the difference of the motor control strategy in ipsilateral and contralateral proximal joints while unperturbed walking and perturbed walking between individuals with CAI and matched controls.

MATERIALS AND METHODS

In a cross-sectional study, 13 participants with unilateral CAI and 13 controls (CON) walked on a split-belt treadmill with and without random left- and right-sided perturbations. EMG amplitudes of muscles at lower extremities were analyzed 200 ms after perturbations, 200 ms before, and 100 ms after (Post100) heel contact while walking. Onset latencies were analyzed at heel contacts and after perturbations. Statistical significance was set at alpha≤0.05 and 95% confidence intervals were applied to determine group differences. Cohen's d effect sizes were calculated to evaluate the extent of differences.

RESULTS

Participants with CAI showed increased EMG amplitudes for NON-rectus abdominus at Post100 and shorter latencies for IN-gluteus maximus after heel contact compared to CON (p<0.05). Overall, leg muscles (rectus femoris, biceps femoris, and gluteus medius) activated earlier and less bilaterally (d = 0.30-0.88) and trunk muscles (bilateral rectus abdominus and NON-erector spinae) activated earlier and more for the CAI group than CON group (d = 0.33-1.09).

CONCLUSION

Unilateral CAI alters the pattern of the motor control strategy around proximal joints bilaterally. Neuromuscular training for the muscles, which alters motor control strategy because of CAI, could be taken into consideration when planning rehabilitation for CAI.

Joint Coordination and Stiffness During Landing in Individuals With Chronic Ankle Instability

The purpose of the present study was to examine the effect of chronic ankle instability (CAI) on lower-extremity joint coordination and stiffness during landing. A total of 21 female participants with CAI and 21 pair-matched healthy controls participated in the study. Lower-extremity joint kinematics were collected using a 7-camera motion capture system, and ground reaction forces were collected using 2 force plates during drop landings. Coupling angles were computed based on the vector coding method to assess joint coordination. Coupling angles were compared between the CAI and control groups using circular Watson-Williams tests. Joint stiffness was compared between the groups using independent t tests. Participants with CAI exhibited strategies involving altered joint coordination including a knee flexion dominant pattern during 30% and 70% of their landing phase and a more in-phase motion pattern between the knee and hip joints during 30% and 40% and 90% and 100% of the landing phase. In addition, increased ankle inversion and knee flexion stiffness were observed in the CAI group. These altered joint coordination and stiffness could be considered as a protective strategy utilized to effectively absorb energy, stabilize the body and ankle, and prevent excessive ankle inversion. However, this strategy could result in greater mechanical demands on the knee joint.

Functional deficits in chronic mechanical ankle instability

BACKGROUND

The interaction of functional and mechanical deficits in chronic ankle instability remains a major issue in current research. After an index sprain, some patients develop sufficient coping strategies, while others require mechanical support. This study aimed to analyze persisting functional deficits in mechanically unstable ankles requiring operative stabilization.

METHODS

We retrospectively analyzed the functional testing of 43 patients suffering from chronic, unilateral mechanical ankle instability (MAI) and in which long-term conservative treatment had failed. Manual testing and arthroscopy confirmed mechanical instability. The functional testing included balance test, gait analysis, and concentric-concentric, isokinetic strength measurements and was compared between the non-affected and the MAI ankles.

RESULTS

Plantarflexion, supination, and pronation strength was significantly reduced in MAI ankles. A sub-analysis of the strength measurement revealed that in non-MAI ankles, the peak pronation torque was reached earlier during pronation (maximum peak torque angle at 20° vs. 14° of supination, p < 0.001). Furthermore, active range of motion was reduced in dorsiflexion and supination. In balance testing, patients exhibited a significant increased perimeter for the injured ankle (p < 0.02). During gait analysis, we observed an increased external rotation in MAI (8.7 vs. 6.8°, p<0.02).

CONCLUSIONS

This study assesses functional deficits existent in a well-defined population of patients suffering from chronic MAI. Impairments of postural sway, gait asymmetries, and asymmetric isokinetic strength can be observed despite long-term functional treatment. The finding that pronation strength is particularly reduced with the foot in a close-to-accident position indicates potential muscular dysfunction in MAI. Possibly, these deficits alongside the underlying mechanical instability characterize patients requiring mechanical stabilization.

The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing

Context:Landing kinetic outcomes are associated with injury risk and may be persistently altered after anterior cruciate ligament injury or reconstruction. However, it is challenging to assess kinetics clinically. The relationship between sound characteristics and kinetics during a limited number of functional tasks has been supported as a potential clinical alternative.Objective:To assess the relationship between kinetics and sound characteristics during a single-leg landing task.Design:ObservationalSetting:Laboratory.Participants:There was total of 26 healthy participants (15 males/11 females, age = 24.8 [3.6] y, height = 176.0 [9.1] cm, mass = 74.9 [14.4] kg, Tegner Activity Scale = 6.1 [1.1]).Intervention:Participants completed single-leg landings onto a force plate while audio characteristics were recorded.Main Outcome Measures:Peak vertical ground reaction force, linear loading rate, instantaneous loading rate, peak sound magnitude, sound frequency were measured. Means and SDs were calculated for each participant’s individual limbs. Spearman rho correlations were used to assess the relationships between audio characteristics and kinetic outcomes.Results:Peak sound magnitude was positively correlated with normalized peak vertical ground reaction force (ρ = .486,P = .001); linear loading rate (ρ = .491,P = .001); and instantaneous loading rate (ρ = .298,P = .03). Sound frequency was negatively correlated with instantaneous loading rate (ρ = −.444,P = .001).Conclusions:Peak sound magnitude may be more helpful in providing feedback about an individual’s normalized vertical ground reaction force and linear loading rate, and sound frequency may be more helpful in providing feedback about instantaneous loading rate. Further refinement in sound measurement techniques may be required before these findings can be applied in a clinical population.

Criteria-Based Return to Sport Decision-Making Following Lateral Ankle Sprain Injury: a Systematic Review and Narrative Synthesis

OBJECTIVE

The aim of this systematic review was to identify prospective studies that used a criteria-based return to sport (RTS) decision-making process for patients with lateral ankle sprain (LAS) injury.

DESIGN

Systematic review and narrative synthesis.

DATA SOURCES

The PubMed (MEDLINE), Web of Science, PEDro, Cochrane Library, SPORTDiscus (EBSCO), ScienceDirect, and Scopus databases were searched to 23 November 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they prospectively applied a criteria-based RTS decision-making process for patients with LAS injury, but were excluded if they merely gathered outcome measures at the RTS time point. Studies were also excluded if patients were recovering from ankle fracture, high ankle sprain, medial ankle sprain, chronic ankle instability or complex ankle injury.

RESULTS

No studies were identified that used a criteria-based RTS decision-making process for patients with LAS injury. We were unable to conduct a quantitative synthesis or meta-analysis, therefore we provide a narrative synthesis of relevant questionnaires, as well as clinical and functional assessments commonly used in studies retrieved in the search.

CONCLUSION

There are currently no published evidence-based criteria to inform RTS decisions for patients with an LAS injury. Based on our narrative synthesis, we propose a number of variables that could be used to develop a criteria-based RTS decision paradigm. Future research should aim to reach consensus on these variables and apply them to actual RTS decisions within prospective study designs. Furthermore, we suggest that complex systems theory and the RTS continuum could be used to inform the development of an RTS decision-making paradigm for athletes with LAS injury.

Leg stiffness control during drop landing movement in individuals with mechanical and functional ankle disabilities

Purpose: Individuals with mechanical ankle instability (MAI) and functional ankle instability (FAI) present with residual movement dysfunctions after an initial lateral ankle sprain. This study investigated leg stiffness control to determine how behavioural characteristics between MAI and FAI differ during single-leg drop landing movement. Methods: Thirty individuals (10 with MAI, 10 with FAI, and 10 healthy controls) participated in this study. During single-leg drop landing movement, we estimated dimensionless leg stiffness, peak vertical force (PVF), change in the displacement of leg movement, loading rate, angular joint movement, and internal joint moment for impaired and unimpaired legs, respectively. Univariate one-way analysis of variance was used for each dependent variable across leg conditions. Results: The MAI group had lower dimensionless leg stiffness with greater change in the displacement of leg movement for the impaired leg than the FAI and control groups. Moreover, reduced leg stiffness was associated with greater hip joint flexion movement in the MAI group, whereas ankle dorsiflexion movement increased to decrease the leg stiffness in the FAI and control groups. Conclusion: These findings indicate that lower leg stiffness in the MAI group than in the FAI group may be attributed to compensatory actions to minimise reliance on their ankle movement after landing.

Lower Limb Joint Kinetics During a Side-Cutting Task in Participants With or Without Chronic Ankle Instability

CONTEXT

Individuals with chronic ankle instability (CAI) demonstrate altered lower limb movement dynamics during jump landings, which can contribute to recurrent injury. However, the literature examining lower limb movement dynamics during a side-cutting task in individuals with CAI is limited.

OBJECTIVE

To assess lower limb joint kinetics and sagittal-plane joint stiffness during the stance phase of a side-cutting task in individuals with or without CAI.

DESIGN

Cohort study.

SETTING

Motion-capture laboratory.

PATIENTS OR OTHER PARTICIPANTS

Fifteen physically active, young adults with CAI (7 men, 8 women; age = 21.3 ± 1.6 years, height = 171.0 ± 11.2 cm, mass = 73.4 ± 15.2 kg) and 15 healthy matched controls (7 men, 8 women; age = 21.5 ± 1.5 years, height = 169.9 ± 10.6 cm, mass = 75.5 ± 13.0 kg).

INTERVENTION(S)

Lower limb 3-dimensional kinematic and ground reaction force data were recorded while participants completed 3 successful trials of a side-cutting task. Net internal joint moments, in addition to sagittal-plane ankle-, knee-, and hip-joint stiffness, were computed from 3-dimensional kinematic and ground reaction force data during the stance phase of the side-cutting task and analyzed.

MAIN OUTCOME MEASURE(S)

Data from each participant's stance phase were normalized to 100% from initial foot contact (0%) to toe-off (100%) to compute means, standard deviations, and Cohen d effect sizes for all dependent variables.

RESULTS

The CAI group exhibited a reduced ankle-eversion moment (39%-81% of stance phase) and knee-abduction moment (52%-75% of stance phase) and a greater ankle plantar-flexion moment (3%-16% of stance phase) than the control group (P range = .009-.049). Sagittal-plane hip-joint stiffness was greater in the CAI than in the control group (t₂₈ = 1.978, P = .03).

CONCLUSIONS

Our findings suggest that altered ankle-joint kinetics and increased hip-joint stiffness were associated when individuals with CAI performed a side-cutting task. These lower limb kinetic changes may contribute to an increased risk of recurrent lateral ankle sprains in people with CAI. Clinicians and practitioners can use these findings to develop rehabilitation programs for improving maladaptive movement mechanics in individuals with CAI.

Evaluating and Differentiating Ankle Instability

Given the prevalence of lateral ankle sprains during physical activity and the high rate of reinjury and chronic ankle instability, clinicians should be cognizant of the need to expand the evaluation of ankle instability beyond the acute time point. Physical assessments of the injured ankle should be similar, regardless of whether this is the initial lateral ankle sprain or the patient has experienced multiple sprains. To this point, a thorough injury history of the affected ankle provides important information during the clinical examination. The physical examination should assess the talocrural and subtalar joints, and clinicians should be aware of efficacious diagnostic tools that provide information about the status of injured structures. As patients progress into the subacute and return-to-activity phases after injury, comprehensive assessments of lateral ankle-complex instability will identify any disease and patient-oriented outcome deficits that resemble chronic ankle instability, which should be addressed with appropriate interventions to minimize the risk of developing long-term, recurrent ankle instability.

Anterior cruciate ligament reconstruction and dynamic stability at time of release for return to sport

OBJECTIVE

Examine dynamic stability using Dynamic Postural Stability Index (DPSI) in athletes following anterior cruciate ligament reconstruction (ACLR) at time of release for return-to-sport (RTS), compared to matched controls.

DESIGN

Cross-sectional case-control study.

SETTING

Sports medicine clinic.

SUBJECTS

Fifteen ACLR athletes who had completed post-operative rehabilitation and were within 6 weeks following release to RTS were age-, gender-, and activity-matched to 15 healthy controls.

MAIN OUTCOME MEASURES

Ground reaction forces (GRFs) were collected using a portable force plate during stabilization from three different single-leg landing tasks. A composite DPSI was calculated using GRFs.

RESULTS

Compared to matched controls, ACLR athletes within 6 weeks of release for RTS did not significantly differ in dynamic postural stability and there were no significant differences between the involved and uninvolved limbs in the ACLR group.

CONCLUSION

Current findings indicate that dynamic postural stability, as measured using the DPSI, is not significantly different in ACLR subjects at time of release for RTS compared to matched controls. In addition, the DPSI was not significantly different between the involved and uninvolved limbs in the ACLR subjects. The results suggest that the post-ACLR rehabilitation program utilized may have adequately restored postural stability in this particular sample.

Kinetic Compensations due to Chronic Ankle Instability during Landing and Jumping

INTRODUCTION

Skeletal muscles absorb and transfer kinetic energy during landing and jumping, which are common requirements of various forms of physical activity. Chronic ankle instability (CAI) is associated with impaired neuromuscular control and dynamic stability of the lower extremity. Little is known regarding an intralimb, lower-extremity joint coordination of kinetics during landing and jumping for CAI patients. We investigated the effect of CAI on lower-extremity joint stiffness and kinetic and energetic patterns across the ground contact phase of landing and jumping.

METHODS

One hundred CAI patients and 100 matched able-bodied controls performed five trials of a landing and jumping task (a maximal vertical forward jump, landing on a force plate with the test leg only, and immediate lateral jump toward the contralateral side). Functional analyses of variance and independent t-tests were used to evaluate between-group differences for lower-extremity net internal joint moment, power, and stiffness throughout the entire ground contact phase of landing and jumping.

RESULTS

Relative to the control group, the CAI group revealed (i) reduced plantarflexion and knee extension and increased hip extension moments; (ii) reduced ankle and knee eccentric and concentric power, and increased hip eccentric and concentric power, and (iii) reduced ankle and knee joint stiffness and increased hip joint stiffness during the task.

CONCLUSIONS

CAI patients seemed to use a hip-dominant strategy by increasing the hip extension moment, stiffness, and eccentric and concentric power during landing and jumping. This apparent compensation may be due to decreased capabilities to produce sufficient joint moment, stiffness, and power at the ankle and knee. These differences might have injury risk and performance implications.

Rehabilitation Exercises Reduce Reinjury Post Ankle Sprain, But the Content and Parameters of an Optimal Exercise Program Have Yet to Be Established: A Systematic Review and Meta-analysis

OBJECTIVES

To determine if exercise-based rehabilitation reduces reinjury following acute ankle sprain. Our secondary objective was to assess if rehabilitation efficacy varies according to exercise content and training volume.

DATA SOURCES

The following electronic databases were searched: EMBASE, MEDLINE, the Cochrane Central Register of Controlled Trials, and Physiotherapy Evidence Database (PEDro).

STUDY SELECTION

Randomized controlled trials investigating the effect of exercise-based rehabilitation programs on reinjury and patient-reported outcomes (perceived instability, function, pain) in people with an acute ankle sprain. No restrictions were made on the exercise type, duration, or frequency. Exercise-based programs could have been administered in isolation or as an adjunct to usual care. Comparisons were made to usual care consisting of 1 or all components of PRICE (protection, rest, ice, compression, elevation).

DATA EXTRACTION

Effect sizes with 95% CIs were calculated in the form of mean differences for continuous outcomes and odds ratios (ORs) for dichotomous outcomes. Pooled effects were calculated for reinjury prevalence with meta-analysis undertaken using RevMan software.

DATA SYNTHESIS

Seven trials (n=1417) were included (median PEDro score, 8/10). Pooled data found trends toward a reduction in reinjury in favor of the exercise-based rehabilitation compared with usual care at 3-6 months (OR, 0.87; 95% CI, 0.48-1.58) with significant reductions reported at 7-12 months (OR, 0.53; 95% CI, 0.38-0.73). Sensitivity analysis based on pooled reinjury data from 2 high quality studies (n=629) also found effects in favor of exercise-based rehabilitation at 12 months (OR, 0.60; 95% CI, 0.49-0.89). Training volume differed substantially across rehabilitation programs with total rehabilitation time ranging from 3.5-21 hours. The majority of rehabilitation programs focused primarily on postural balance or strength training.

CONCLUSIONS

Exercise-based rehabilitation reduces the risk of reinjury following acute ankle sprain when compared with usual care alone. There is no consensus on optimal exercise content and training volume in this field. Future research must explicitly report all details of administered exercise-based rehabilitation programs.

Acute lateral ankle sprain to chronic ankle instability: a pathway of dysfunction

Lateral ankle sprains (LAS) have been reported as one of the most common musculoskeletal injuries observed in sports and in individuals who are recreationally active. Approximately 40% of individuals who sustain a LAS develop a condition known as chronic ankle instability (CAI). Years of research has identified numerous impairments associated with CAI such as decreases in range of motion (ROM), strength, postural control, and altered movement patterns during functional activities when compared to individuals with no LAS history. As a result, an impairment-based rehabilitation model was developed to treat the common impairments associated with CAI. The impairment-based rehabilitation model has been shown to be an effective rehabilitation strategy at improving both clinical and patient-oriented outcomes in patients with CAI. To date, the efficacy of an impairment-based rehabilitation model has not been evaluated in patients with an acute LAS. Prior to implementing an impairment-based model for the treatment of an acute LAS, similarities between impairments associated with acute LAS and CAI across the spectrum of the healing process is warranted. Therefore, the purpose of this review paper is to compare and contrast impairments and treatment techniques in individuals with an acute LAS, sub-acute LAS, and CAI. A secondary purpose of this review is to provide clinical commentary on the management of acute LAS and speculate how the implementation of an impairment-based rehabilitation strategy for the treatment of acute LAS could minimize the development of CAI. The main findings of this review were that similar impairments (decreased ROM, strength, postural control, and functional activities) are observed in patients with acute LAS, sub-acute LAS, and CAI, suggesting that the impairments associated with CAI are a continuation from the original impairments developed during the initial LAS. Therefore, the use of an impairment-based model may be advantageous when treating patients with an acute LAS.

The effect of knee flexor and extensor fatigue on shock absorption during cutting movements after a jump landing

BACKGROUND

Sporting situations include instances of continuous and/or integrated movements. However, the effect of fatigue on the performance of these movements remains unclear.

PURPOSE

To investigate the effect of knee flexor and extensor fatigue on the shock absorption strategy of the lower limb during cutting movements performed after jump landings.

METHODS

Twenty-four healthy participants performed cutting movements following jump landings from two heights - 30cm and 40cm - and under three levels of lower limb fatigue: pre-fatigue (100% peak knee extension torque), and post-fatigue 50% (post-50%) and 30% (post-30%) peak knee extension torque. Fatigue was induced by repeated isokinetic flexion/extension of the knee (60°/s).

RESULTS

Compared to the pre-fatigue condition, power and work at the knee joint decreased under both post-50% and post-30% conditions (P<0.001), while the work performed by the ankle (P<0.001) increased significantly. An increase in height from 30cm to 40cm was associated with an increase in the range of motion of the ankle (P<0.001) and knee (P=0.022), peak vertical ground reaction force (P<0.001), rate of loading (P<0.001), knee stiffness (P=0.026) and peak power of the knee (P<0.001), as well as the work performed by the knee (P<0.001) and hip (P<0.001) joints.

CONCLUSIONS

Under substantial muscle fatigue the proportion of shock absorption contributed by the knee for cutting movements performed after jump landings from a height of 40cm decreased; there was an adaptive increase in the contribution by the ankle.

Military personnel with self-reported ankle injuries do not demonstrate deficits in dynamic postural stability or landing kinematics

BACKGROUND

The odds of sustaining non-contact musculoskeletal injuries are higher in Special Operations Forces operators than in infantry soldiers. The ankle is one of the most commonly injured joints, and once injured can put individuals at risk for reinjury. The purpose of this study was to determine if any differences in postural stability and landing kinematics exist between operators with a self-reported ankle injury in the past one year and uninjured controls.

METHODS

A total of 55 Special Operations Forces operators were included in this analysis. Comparisons were made between operators with a self-reported ankle injury within one-year of their test date (n=11) and healthy matched controls (n=44). Comparisons were also made between injured and uninjured limbs within the injured group. Dynamic postural stability and landing kinematics at the ankle, knee, and hip were assessed during a single-leg jump-landing task. Comparisons were made between groups with independent t-tests and within the injured group between limbs using paired t-tests.

FINDINGS

There were no significant differences in dynamic postural stability index or landing kinematics between the injured and uninjured groups. Anterior-posterior stability index was significantly higher on the uninjured limb compared to the injured limb within the injured group (P=0.02).

INTERPRETATION

Single ankle injuries sustained by operators may not lead to deficits in dynamic postural stability. Dynamic postural stability index and landing kinematics within one year after injury were either not affected by the injuries reported, or injured operators were trained back to baseline measures through rehabilitation and daily activity.

Relationship between ankle frontal plane kinematics during different functional tasks

Increased inversion following lateral ankle sprain and in patients with chronic ankle instability (CAI) is thought to contribute to recurrent injury and feelings of instability, however, there are no biomechanic assessment tools readily available to evaluate for excessive inversion prior to or following lateral ankle sprains. Before establishing a clinically useful biomechanic assessment tool, it is important to understand whether there is a relationship in the extent of ankle frontal plane motion across various tasks to help determine if one task or a combination of tasks would be most appropriate when evaluating patients. The purpose of this preliminary study was to analyze the relationship between ankle frontal plane kinematics during walking, step-down, and jump-landing tasks. Fifty-six recreationally active adults (gender=M:26;F:30, age=21.2±3.2, height=171.3±8.0cm, mass=75.6±15.4) volunteered. Main outcome measures were ankle frontal plane motion at initial contact and peak inversion during aerial phases across 3 tasks (walking, step-down, and jump-landing). Relationships between ankle frontal plane kinematics were analyzed by Pearson product-moment correlation coefficient (r). There were strong correlations in peak inversion during the aerial phase between the step-down and walking (r=0.68; p<0.001) and step-down and jump-landing (r=0.75; p<0.001) and at initial contact between step-down and walking (r=0.73; p<0.001) and step-down and jump-landing (r=0.72; p<0.001). Moderate correlations were identified during aerial (r=0.32; p=0.015) and at initial contact (r=0.46; p<0.001) between walking and jump-landing. The strong relationship between the amount of inversion exhibited across various tasks suggest that a single evaluation test may be sufficient in the identification of abnormal ankle biomechanics.

Evidence review for the 2016 International Ankle Consortium consensus statement on the prevalence, impact and long-term consequences of lateral ankle sprains

Lateral ankle sprains (LASs) are the most prevalent musculoskeletal injury in physically active populations. They also have a high prevalence in the general population and pose a substantial healthcare burden. The recurrence rates of LASs are high, leading to a large percentage of patients with LAS developing chronic ankle instability. This chronicity is associated with decreased physical activity levels and quality of life and associates with increasing rates of post-traumatic ankle osteoarthritis, all of which generate financial costs that are larger than many have realised. The literature review that follows expands this paradigm and introduces emerging areas that should be prioritised for continued research, supporting a companion position statement paper that proposes recommendations for using this summary of information, and needs for specific future research.

Recovery From a First-Time Lateral Ankle Sprain and the Predictors of Chronic Ankle Instability: A Prospective Cohort Analysis

BACKGROUND

Impairments in motor control may predicate the paradigm of chronic ankle instability (CAI) that can develop in the year after an acute lateral ankle sprain (LAS) injury. No prospective analysis is currently available identifying the mechanisms by which these impairments develop and contribute to long-term outcome after LAS.

PURPOSE

To identify the motor control deficits predicating CAI outcome after a first-time LAS injury.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Eighty-two individuals were recruited after sustaining a first-time LAS injury. Several biomechanical analyses were performed for these individuals, who completed 5 movement tasks at 3 time points: (1) 2 weeks, (2) 6 months, and (3) 12 months after LAS occurrence. A logistic regression analysis of several "salient" biomechanical parameters identified from the movement tasks, in addition to scores from the Cumberland Ankle Instability Tool and the Foot and Ankle Ability Measure (FAAM) recorded at the 2-week and 6-month time points, were used as predictors of 12-month outcome.

RESULTS

At the 2-week time point, an inability to complete 2 of the movement tasks (a single-leg drop landing and a drop vertical jump) was predictive of CAI outcome and correctly classified 67.6% of cases (sensitivity, 83%; specificity, 55%; P = .004). At the 6-month time point, several deficits exhibited by the CAI group during 1 of the movement tasks (reach distances and sagittal plane joint positions at the hip, knee and ankle during the posterior reach directions of the Star Excursion Balance Test) and their scores on the activities of daily living subscale of the FAAM were predictive of outcome and correctly classified 84.8% of cases (sensitivity, 75%; specificity, 91%; P < .001).

CONCLUSION

An inability to complete jumping and landing tasks within 2 weeks of a first-time LAS and poorer dynamic postural control and lower self-reported function 6 months after a first-time LAS were predictive of eventual CAI outcome.