Unilateral Ankle Research Articles

Does a Patient’s Self-Reported Ability to Weightbear Immediately after Injury Predict Stability for Ankle Fractures

Category: Trauma Introduction/Purpose: Determining the stability of ankle fractures, particularly for apparent isolated Weber B fibula fractures, can be difficult. While the ultimate goal remains achieving an anatomic mortise, different techniques to predict ankle stability such as stress and weightbearing radiographs have been utilized with variable results. History of injury and the ability to walk after sustaining ankle trauma may be predictive of stability. Therefore, this study seeks to determine whether a patient’s ability to fully weight bear immediately after injury is an effective indicator for ankle stability following ankle fracture. Methods: A prospective review was conducted of patients sustaining isolated, unilateral ankle fractures presenting to two level I trauma centers. Aside from demographic data and fracture characteristics, a patient’s ability or inability to fully weightbear immediately after injury was elicited by interview at their initial assessment. This information was correlated with their ankle radiographs, which were deemed stable or unstable fractures based on commonly used indices to assess ankle stability. Results: 102 consecutive patients sustaining ankle fractures were included. Mean age was 45. When analyzing the entire cohort, patients who were able to ambulate immediately after injury were 10 times more likely to have a stable ankle fracture than those who could not bear weight (odds ratio (OR) 9.9 (P < 0.001). The positive predictive value (PPV) for being able to fully weightbear as it relates to a stable ankle fracture was 77%. Additionally, inability to weightbear was 89% specific for an unstable fracture. When separately analyzing patients with apparent isolated fibula fractures (n=56), the PPV was 75%, specificity was 83%, while the OR was 5.8 (p=0.003) for those who could fully bear weight having a stable ankle fracture. Conclusion: This study demonstrates that patient’s self-reported ability to fully weightbear immediately after injury is a specific and convenient prognostic indicator for ankle stability across a range of ankle fracture subtypes. Future studies can analyze whether initial weightbearing accurately predicts ultimate management and good outcome.

Eccentric Training Improves Ankle Evertor and Dorsiflexor Strength and Proprioception in Functionally Unstable Ankles.

The aim of this study was to investigate the effects of a combined eccentric-concentric exercise program of the ankle evertors and dorsiflexors on proprioception in functionally unstable ankles. Thirteen male recreational athletes with unilateral functional ankle instability were admitted to this study. The unaffected opposite ankles were used as controls. The functionnaly unstable ankle of the subjects performed an isokinetic exercise program of the ankle evertors and dorsiflexors in a combined eccentric-concentric mode for 3 days per week for 6 wks. Before and after the isokinetic exercise program, active and passive joint position sense and kinesthesia and isokinetic strength of the ankle joint were evaluated. Active and passive joint position sense error scores for inversion (P < 0.01-0.001) and plantarflexion (P < 0.05-0.001) direction and kinesthesia scores for inversion (P < 0.001) and plantarlexion (P < 0.01) direction showed significant reductions after 6 wks of intervention in the functionnaly unstable ankle. In addition, eccentric peak torques for the ankle evertor and dorsiflexors represented significant (P < 0.001) increases in the functionnaly unstable ankle compared with the control ankle. The results of this study suggest that it is possible to improve proprioceptive acuity of the ankle joint after a 6-wk eccentric-concentric isokinetic training program in functionally unstable ankles.

The influence of passive-dynamic ankle-foot orthosis bending axis location on gait performance in individuals with lower-limb impairments

BackgroundPassive-dynamic ankle-foot orthoses are commonly prescribed to augment impaired ankle muscle function, however their design and prescription are largely qualitative. One design includes a footplate and cuff, and flexible strut connecting the two. During gait, deflection occurs along the strut, with the greatest deflection at a central bending axis. The vertical location of the axis can affect lower extremity biomechanics. The goal of this study was to investigate the influence of bending axis location on gait performance. MethodsFor thirteen participants with unilateral ankle muscle weakness, an additive manufacturing framework was used to fabricate passive-dynamic ankle-foot orthosis struts with central and off-center bending axes. Participants walked overground while electromyographic, kinetic and kinematic data were collected for three different bending axes: proximal (high), central (middle) and distal (low), and the participants indicated their order of bending axis preference after testing. Gait measures and preference effect sizes were examined during six regions of the gait cycle. FindingsA few differences between bending axes were observed: in the first double-leg support peak plantarflexion angle, peak dorsiflexion moment and positive hip work, in the early single-leg support peak knee extension moment and positive ankle and knee work, and in the late single-leg support gastrocnemius activity and vertical ground reaction force impulse. In addition, preference was strongly related to various gait measures. InterpretationDespite the observed statistical differences, altering bending axis location did not produce large and consistent changes in gait performance. Thus, individual preference and comfort may be more important factors guiding prescription.

Unique Center of Pressure Profiles in Unilateral Compared to Bilateral End-Stage Ankle Arthritis Patients

nkle arthritis is a debilitating condition that alters the mobility and stability of the ankle joint during both static and dynamic tasks. Symmetrical contribution to balance performance has been posited to improve balance performance. However, few studies have examined the impact of unilateral compared to bilateral joint involvement on balance in individuals with ankle arthritis. PURPOSE: To quantify balance performance in patients with unilateral (UA) compared to bilateral (BA) end-stage ankle arthritis. METHODS:Twenty-three UA and 21 BA patients performed three 10-second quiet standing trials with their feet placed together. Ground reaction forces were recorded using two force platforms, one under each foot (1200 Hz, BP600-900, AMTI). Center of pressure (CoP) measures were calculated using custom software (Matlab, Mathworks). CoP excursions in the anteroposterior (AP), mediolateral (ML) and resultant directions (RES) were calculated as described by Prieto et al. (1996). Independent samples t-tests were used to compare the involved (INV) and uninvolved limbs (UN) in the UA to the average of the left and right limbs in BA. Significance was set at p < 0.05. RESULTS:No demographic differences existed between the UA and BA patients. No differences existed between the INV and BA group for the RES (p=0.499; INV: 16.96±7.11 mm; BA: 16.08±4.48 mm), AP (p=0.190; INV: 6.05±1.41 mm; BA: 6.16±1.29 mm) or ML excursions (p= 0.431; INV: 14.39±7.26 mm; BA: 13.38±4.83 mm). When comparing the UN limb to the BA group, the UN limb had significantly greater RES (p=0.040; UN: 20.25±8.57 mm) and ML excursions (p=0.029; UN: 17.97±8.51) compared to the BA group. No differences were observed in AP excursions between the UN (p=0.255; UN: 5.83±1.67) and BA groups. CONCLUSIONS: These data indicate that the contribution of each limb to postural stability is unique in individuals with unilateral end-stage ankle arthritis. Interestingly, no differences were observed in AP CoP excursions between the two groups. Further, it should be noted that CoP excursions were significantly greater in the UN limb compared to the BA group. This is contrary to the notion of “better balance” which would generally be associated with healthy limb, but may be an effect of compensating for the INV limb.

Intracranial epidural hemorrhage during lumbar spinal surgery.

The authors report a case of intracranial epidural hemorrhage (ICEH) during spinal surgery. We could not find ICEH, though we recorded transcranial electrical stimulation motor evoked potentials (TcMEPs). A 35-year-old man was referred for left anterior thigh pain and low back pain that hindered sleep. Sagittal T2-weighted magnetic resonance imaging revealed an intradural tumor at L3-L4 vertebral level. We performed osteoplastic laminectomy and en bloc tumor resection. TcMEPs were intraoperatively recorded at the bilateral abductor digiti minimi (ADM), quadriceps, tibialis anterior and abductor hallucis. When we closed a surgical incision, we were able to record normal TcMEPs in all muscles. The patient did not fully wake up from the anesthesia. He had right-sided unilateral positive ankle clonus 15 min after surgery in spite of bilateral negative of ankle clonus preoperatively. Emergent brain computed tomography scans revealed left epidural hemorrhage. The hematoma was evacuated immediately via a partial craniotomy. There was no restriction of the patient's daily activities 22 months postoperatively. We should pay attention to clinical signs such as headache and neurological findgings such as DTR and ankle clonus for patients with durotomy and cerebrospinal fluid (CSF) leakage. Spine surgeons should know that it was difficult to detect ICEH by monitoring with TcMEPs.

Four Weeks of Balance Training does not Affect Ankle Joint Stiffness in Subjects with Unilateral Chronic Ankle Instability.

Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with chronic ankle instability (CAI) but the biomechanical pathways underlying the clinical outcomes are still unknown. This study was conducted to determine if a 4-week balance training intervention can alter the mechanical characteristics in ankles with CAI. 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. At baseline, the mean values of the inversion stiffness (0.69 ± 0.37 Nm/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 ± 0.41 Nm/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. 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. Randomized controlled clinical trial; Level of evidence, 1.

High resolution ultrasonography and magnetic resonance imaging in the evaluation of tendino-ligamentous injuries around ankle joint

PurposeThe aim of this study was to rule out the diagnostic accuracy of both ultrasonography (US) and magnetic resonance imaging (MRI) for the assessment of tendino-ligamentous pain around the ankle joint. Patients and methodsThis study included 35 patients (25 females and 10 males) complaining of unilateral ankle pain (acute or chronic), and they were subjected to plain X-ray (to exclude osseous pathology), US and MRI examinations. ResultsThe study included 35 patients where 20 patients showed tendon pathology that was diagnosed into 21 pathological entities by both US and MRI imaging modalities with no difference in interpretation between them. 21 patients had pathological ligaments which were diagnosed by both ultrasound and MRI. However, two ligamentous lesions were diagnosed as partial tear by US, while MRI diagnosed them as complete tear. Associated findings were also diagnosed as retrocalcaneal bursitis in two patients, joint effusion in four patients and joint synovitis in three patients. ConclusionUS is an excellent tool for imaging soft tissue abnormalities, as it allows rapid, in-expensive detailed examination of the structures of the ankle joint. US and MRI are two complementary tools of investigation with the former being used as primary effective tool of investigation and the latter is done to confirm the diagnosis.

Lipid profile of human synovial fluid following intra-articular ankle fracture.

This study characterizes the metabolic profile of synovial fluid after intra-articular ankle fracture with an emphasis on changes in the lipid profile. Bilateral ankle synovial fluid from 19 patients with unilateral intra-articular ankle fracture was submitted for metabolic profiling. Contralateral ankle synovial fluid from each patient served as a matched control. Seven patients participated in a second bilateral synovial fluid collection after 6 months. Random forest classification, matched pairs t-tests (α < 0.01), repeated measures ANOVA with post-test contrasts (α < 0.01), correlation to cytokines and matrix metalloproteinases, and fracture and injury classification analyses yielded key lipid biomarkers in synovial fluid following intra-articular fracture. Free fatty acids, sphingomyelins, and lysolipids demonstrated significant elevation in fractured ankles at baseline. Fatty acids and sphingomyelins showed a significant decrease 6 months post-surgery. Random forest analysis showed predominantly fatty acids differentiating between groups. Significant correlations included fatty acids, sphingomyelins, and lysolipids with inflammatory cytokines and matrix metalloproteinases. Fracture classification showed increased fatty acids, lysolipids, and inositol metabolites as fracture severity increased. Fatty acid and sn-1 lysolipid elevation could be detrimental to the joint, as these strongly correlated with matrix metalloproteinases and TNF-α. This elevation also suggests involvement of phospholipase A2 , a potential target for therapeutic intervention. Together with elevated 2-hydroxyl fatty acids, these findings suggest elevated sn-1 lysolipids, sphingomyelins, and subsequent lipid metabolites in synovial fluid as biomarkers of ankle injury. Reversal of this signature after 6 months suggests temporary involvement of these metabolites in disease progression, although they may activate signaling pathways which drive progression to osteoarthritis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:657-666, 2017.

Computed Tomographic Evaluation of Joint Geometry in Patients With End-Stage Ankle Osteoarthritis.

Deformation of the talus and the distal tibia can be frequently observed during ankle joint osteoarthritis (OA). The aim of this study was to objectify these morphologic changes. We hypothesized that a flattening of the talus and a broadening of the distal tibia surface occurs in end-stage OA of the ankle joint. Twenty-seven computed tomography (CT) ankle joint examinations of unilateral ankle OA were matched by sex and age with 27 CT examinations of healthy ankle joints. Three-dimensional reformatting and measurements were performed with geometry analysis software. The following parameters were assessed: sagittal radius of the talus, talus height, and mediolateral and anteroposterior width of the distal tibial joint surface. Medial, midsagittal, and lateral sagittal arc radii of osteoarthritic tali were significantly larger compared to tali of controls. There was a statistically significant difference in the height of the osteoarthritic talar dome in the medial and in the lateral frontal segment and in the medial central segment compared to tali of controls. The anteroposterior width and the sagittal curvature of the distal tibia was significantly larger in OA ankles than in the control group. The mediolateral measurements were comparable across both groups. Flattening of the talus appears to be more pronounced in the frontal aspect of the talus. The distal tibia broadens anteroposteriorly. These findings may contribute to better understanding of ankle OA development. Level III, retrospective comparative cohort study.

The effects of total ankle replacement on ankle joint mechanics during walking

BackgroundEnd-stage ankle arthritis impairs joint function and patients' mobility. Total ankle replacement is a surgical procedure to treat severe ankle arthritis. Salto Talaris Anatomic AnkleTM (STAA) was designed to mimic the normal ankle anatomy and flexion/extension of the ankle movement. The purpose of this study was to examine the effect of an STAA ankle replacement on ankle joint function and mechanics during gait. MethodsFive patients with end-stage unilateral ankle arthritis were recruited. Patients performed level walking in a laboratory setting on 2 occasions, prior to and 3 months after the STAA ankle surgeries. American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score was obtained. A 12-camera motion capture system was used to perform walking analysis. Gait temporo-spatial parameters and ankle joint mechanics were evaluated. Paired Student's t tests and non-parametric Wilcoxon matched tests were performed to examine the differences in biomechanical variables between the pre- and post-surgery walking conditions. ResultsCompared to the pre-surgical condition, at 3 months of post-STAA surgery, patients experienced greater improvement in AOFAS hindfoot score (p = 0.0001); the STAA ankle demonstrated a 31% increase in ankle joint excursion (p = 0.045), a 22% increase in ankle plantarflexor moment (p = 0.075), a 60% increase in ankle power absorption (p = 0.023), and a 68% increase in ankle power production (p = 0.039). Patients also demonstrated a 26% increase in walking speed (p = 0.005), a 20% increase in stride length (p = 0.013), a 15% decrease in double support time (p = 0.043), and a 5% decrease in total stance time (p = 0.055). ConclusionThree months after surgeries, the STAA patients experienced improvements in ankle function and gait parameters. The STAA ankle demonstrated improved ankle mechanics during daily activities such as walking.

Role of ultrasonography in assessment of tendons around ankle joint

Introduction Ankle injury is a common condition secondary to trauma; ultrasonography plays a big role in the assessment of a variety of musculoskeletal disorders. These improvements along with economic factors and availability have resulted in renewed interest in using ultrasound (US) as a diagnostic tool. As such, the efficacy of US has been compared with other modalities, in particular MRI, as a cost effective imaging alternative. Context US is a rapid, accurate, and cheap diagnosing tool. Aims The aim of this study was to show the efficacy of US as a cost effective diagnostic imaging alternative. Settings and design Selected individuals of ankle or foot injuries by clinical examination, with no exclusion criteria. Performing real time ankle US bilaterally for each patient. Participants and methods They will be divided into two groups: first control group which demonstrates 25 asymptomatic ankle ligaments and tendons. Second group includes 25 patients suffering from unilateral or bilateral ankle as sequelae of trauma. All patients will be subjected to history taking and real-time high-resolution ultrasonography. The procedures followed were in accordance with the ethical standards and approval by Benha University. Statistical analysis used Parametric analysis of our results using Excel program. Results Forty pathological entities were diagnosed by both utilized imaging modalities in 25 cases. The study included 11 cases with tendon pathology that were interpreted into 13 pathological entities by all imaging modalities. However, US missed two cases: (a) a case of partial tear of Achilles tendon; (b) a case of flexor hallucis longus tenosynovitis. US could detect all of the ligamentous lesions identified in three cases, which were interpreted as tear by MRI, likely due to US anisotropy effect. Conclusion Ankle US is a rapid, accurate, and cost effective imaging modality.

Changes of One-Leg Standing Balance of Ipsilateral and Contralateral Lower-Limb Following Unilateral Isokinetic Exercise of Ankle Joint in Young Adults

Purpose: The purpose of this study was to investigate the effects of a four week unilateral isokinetic exercise program applied to ankle on the one-leg stance balance performance of ipsilateral and contralateral lower-limbs. Methods: Subjects were randomly assigned to either a right ankle training program (n=12) or a control group (n=12). The training group received unilateral ankle isokinetic exercise of the dominant side for 4 weeks, whereas control group did not. Ipsilateral and con tralateral one-leg balance were measured before and after intervention using the Biodex Balance System. Results: Improvements of stability scores, such as APSI, MLSI, and OSI, from pre-test to post-test were significantly different greater for the training group when the control. Conclusion: The results of this study suggest unilateral ankle strengthening exercise transfers benefit to the untrained limb by a cross-education effect, and that this type of exercise should be considered to improve one-leg standing balance of trained and untrained low er-limbs.

Effects of balance training on post-sprained ankle joint instability.

Effects of balance training on post-sprained ankle joint instability.

Simulated Ankle Equinus Affects Knee Kinematics During Gait.

It is critical to distinguish gait compensations from true abnormalities when planning interventions to improve gait in individuals with neuromuscular disorders. The aim of this study was to determine the effect of isolated ankle equinus on knee kinematics during the initial contact phase of gait. Ten healthy subjects (29 + 4.3years) participated, and testing occurred in a motion analysis laboratory. This cross-sectional study investigated five gait conditions in each subject: shoe alone, shoe with unilateral ankle foot orthosis locked at neutral, 10°, 20°, and 30° of fixed ankle plantar flexion. Gait kinematics were recorded and calculated with 3D motion analysis. The difference between the shoe and each brace condition was analyzed by repeated-measures ANOVA. The primary outcome was knee flexion at initial contact. With greater than 10° simulated ankle equinus, the primary gait compensation pattern was increased knee flexion at initial contact. A significant degree of knee flexion occurred ranging from 7° to 22°. Our data suggests that observed knee flexion at initial contact may be a compensation pattern in individuals with >10° ankle equinus. However, in individuals with ≤10° ankle equinus, observed knee flexion may represent a true gait deviation. This has clinical significance in the realm of cerebral palsy for treatment planning to improve gait.

Effect of Preoperative Stress Radiographic Findings on Radiographic and Clinical Outcomes of the Modified Broström Procedure for Chronic Ankle Instability

The purpose of the present study is to evaluate whether findings of instability on preoperative stress radiographs of patients with chronic ankle instability affects the radiographic and clinical outcomes after a modified Broström procedure. A total of 45 consecutive patients (45 ankles) who had undergone the modified Broström procedure for unilateral ankle joint instability and were followed up for ≥2 years were selected. The patients were classified into 2 groups according to the results of the preoperative stress radiographs: 1 group with positive findings (35 [77.8%] patients; stress-positive group) and 1 group with negative findings (10 [22.2%] patients; stress-negative group). The radiographic and clinical outcomes were compared between the 2 groups. The mean preoperative talar tilt measured on the stress radiograph was 14.4° ± 4.2° and 4.8° ± 2.6° in the stress-positive and stress-negative groups, respectively, a statistically significant difference. Postoperative talar tilt improved in both groups, with a mean final talar tilt of 5.4° ± 3.4° in the stress-positive group (p < .001) and 3.0° ± 1.5° in the stress-negative group (p = .038). The average American Orthopaedic Foot and Ankle Society ankle-hindfoot score in the stress-positive and stress-negative groups improved from 65.1 ± 14.6 to 90.0 ± 6.3 (p < .001) and 72.5 ± 9.3 to 92.6 ± 7.8 (p = .007), respectively. The mean postoperative satisfaction rate was 83.9 ± 11.9 and 85.0 ± 11.8 in the 2 groups. No statistically significant differences were seen in the preoperative and postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot scores or in postoperative satisfaction rates between the 2 groups.

Comparative gait initiation kinematics between simulated unilateral and bilateral ankle hypomobility: Does bilateral constraint improve speed performance?

Improvement of motor performance in unilateral upper limb motor disability has been shown when utilizing inter-limb coupling strategies during physical rehabilitation. This suggests that ‘default’ bilateral central motor commands are facilitated. Here, we tested whether this bilateral motor control principle may be generalized to the lower limbs during gait initiation, which involves alternate bilateral actions. Disability was simulated by strapping to produce ankle hypomobility. Healthy adult subjects initiated gait at a self-paced speed with no ankle constraint (control), or with the stance, swing or bilateral ankles strapped. The duration of the anticipatory postural adjustments lengthened and the center of mass instantaneous progression velocity at foot-off decreased when the ankle was strapped. During the step execution phase, progression velocity at foot-contact was higher when both ankles were strapped compared to unilateral strapping of the stance ankle. These findings suggest that bilateral central motor commands are favored during walking tasks. Indeed, unilateral constraint of the stance ankle should compel the central nervous system to adapt specific commands to the constraint and normal sides whereas the ‘default’ bilateral motor commands would be utilized when both ankles are strapped leading to better kinematics performance. Bilateral in-phase upper limb coordination and bilateral alternating lower limb locomotor movements may share similar control mechanisms.

An experimental comparison of the relative benefits of work and torque assistance in ankle exoskeletons.

Techniques proposed for assisting locomotion with exoskeletons have often included a combination of active work input and passive torque support, but the physiological effects of different assistance techniques remain unclear. We performed an experiment to study the independent effects of net exoskeleton work and average exoskeleton torque on human locomotion. Subjects wore a unilateral ankle exoskeleton and walked on a treadmill at 1.25 m·s(-1) while net exoskeleton work rate was systematically varied from -0.054 to 0.25 J·kg(-1)·s(-1), with constant (0.12 N·m·kg(-1)) average exoskeleton torque, and while average exoskeleton torque was systematically varied from approximately zero to 0.18 N·m·kg(-1), with approximately zero net exoskeleton work. We measured metabolic rate, center-of-mass mechanics, joint mechanics, and muscle activity. Both techniques reduced effort-related measures at the assisted ankle, but this form of work input reduced metabolic cost (-17% with maximum net work input) while this form of torque support increased metabolic cost (+13% with maximum average torque). Disparate effects on metabolic rate seem to be due to cascading effects on whole body coordination, particularly related to assisted ankle muscle dynamics and the effects of trailing ankle behavior on leading leg mechanics during double support. It would be difficult to predict these results using simple walking models without muscles or musculoskeletal models that assume fixed kinematics or kinetics. Data from this experiment can be used to improve predictive models of human neuromuscular adaptation and guide the design of assistive devices.

Effect of experimentally reduced distal sensation on postural response to hip abductor/ankle evertor muscle vibration

This study assessed whether postural responses induced by vibratory perturbations of the hip abductors and ankle evertors, were modified when distal tactile sensation was experimentally reduced through cooling. Sixteen healthy subjects were investigated pre and post cooling. Subjects stood with their eyes closed with a stance width of 4cm. A 2s vibratory stimulus was applied to the left or right hip abductor or ankle evertor muscle. The order of the site and side of the stimulation was randomised. The postural response to hip abductor and ankle evertor vibration was recorded using 3D motion analysis (Codamotion, Leicestershire). Medio-lateral centre of pressure motion was simultaneously recorded during quiet standing via a force plate (Kistler, UK). Pre-cooling people responded to unilateral ankle vibration with an ipsilateral translation and tilt of the pelvis, and an ipsilateral tilt of the trunk. People responded to unilateral hip vibration with a contralateral translation and tilt of the pelvis, and an ipsilateral tilt of the trunk. Following an experimental reduction in distal tactile sensation there was a significant reduction in the amplitude of pelvic tilt in response to ankle vibration (F(6.2)=P<0.05) and a significant increase in amplitude of pelvic tilt in response to hip vibration (F(5.2)=P<0.05). This suggests that the sensitivity to artificial stimulation of hip proprioception increases with distal cooling, possibly indicating a change in the gain/weighting placed upon sensory information from the hips.

Those with Unilateral Chronic Ankle Instability have Impaired Unilateral Single Limb Balance and Self-Reported Function

Chronic ankle instability (CAI) is a common sequela of an ankle sprain. Single limb balance impairments have been reported in those with CAI, but it is unclear whether these deficits are found on only the self-reported more dysfunctional limb or if they are bilateral. PURPOSE: To determine whether single limb balance deficits exist when comparing the self-reported CAI limb to the healthy limb in subjects with unilateral CAI. METHODS: 26 subjects with self-reported unilateral CAI participated. Each participant completed the Foot and Ankle Ability Measure Sport Scale (FAAMS). A score of <80% on the FAAMS was considered as an ankle with CAI. All subjects performed 3, 10-second trials of single limb stance with eyes open on a force plate and 3, 20-second trials of single limb balance on a firm surface (SLBT) with eyes closed. From the force plate, time-to-boundary was calculated in the mediolateral (TTBML) and anteroposterior (TTBAP) directions. TTB estimates the amount of time a person has to make a postural correction to prevent balance loss. Dependent variables included the FAAMS score (%), TTBAP and TTBML (s), and mean errors committed during the SLBT. Paired t-tests were used to compare the dependent variables between limbs (self-reported CAI vs. healthy limb) for all comparisons. Alpha was set a priori at p<0.05 for all analyses. RESULTS: The CAI limb (64.2±11.7%) had lower FAAMS scores than the healthy limb (98.1±5.6%, p<0.001). TTBML (CAI: 1.8±0.7s, Healthy: 2.1s, p<0.001) and TTBAP (CAI: 4.9±1.4, Healthy: 5.8±1.9s, p<0.001) were lower on the CAI limb. The CAI limb (CAI: 2.49±1.55) also had more SLBT errors than the healthy limb (1.77±1.48, p=0.006) CONCLUSION: Those with unilateral CAI reported significantly more disability when performing sport-related activities on the CAI limb relative to the healthy limb. These individuals, while balancing on the CAI limb, had significantly less time to make postural corrections in both the ML and AP directions with eyes open. Similarly, these individuals also made more errors on an eyes closed clinical balance test on the CAI limb. Based on these results, less time to make postural corrections with eyes open and more errors with eyes closed may be contributing factors for the reported CAI limb disability. This project was supported by: NIAMS 1R03AR061561.

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.