Ankle sensorimotor control and eversion strength after acute ankle inversion injuries

Dynamic force distribution during level walking under the feet of patients with chronic ankle instability

OBJECTIVES

To examine changes in the pattern of force transfer between the foot and the floor associated with chronically sprained ankles by measuring the peak forces and their timing under several regions of the feet during level walking.

METHODS

Twelve young male subjects (mean (SD) age 21 (2) years) with recurrent ankle sprains were studied. Seven of them had unilateral and bilateral chronic instability and laxity, and five had bilateral instability. Twelve healthy men (without orthopaedic or medical disease) served as a control group. Subjects walked at their own pace along a 7 m walkway, which included a Mini-EMED pressure distribution measuring system. The variables measured were relative peak force (fraction of body weight) and relative timing (fraction of stance time). These variables were measured under six regions of interest in each foot print: heel, midfoot, medial, central, and lateral forefoot, and toes.

RESULTS

(a) A significant delay to the time of peak force under the central and lateral forefoot and toes in subjects with chronic ankle instability. (b) A significant decrease in the relative forces under the heel and toes and an increase in the relative forces under the midfoot and lateral forefoot in subjects with chronic ankle instability. (c) In the patients with unilateral instability, there were no significant differences in any of the variables between the injured and non-injured foot.

CONCLUSIONS

In patients with chronic ankle instability, there is a slowing down of weight transfer from heel strike to toe off, a reduced impact at the beginning and end of the stance phase, and a lateral shift of body weight.

Sensorimotor control is impaired in dancers with functional ankle instability

BACKGROUND

Factors potentially causing chronic instability after ankle inversion sprains have rarely been examined during the injuring movement.

PURPOSE

To compare control of ankle movement during quiet stance and after inversion perturbation in chronically unstable ankles (n = 16) with healthy controls (n = 26).

METHODS

Movement control was measured as magnitude of lateral ankle oscillation, using 3SPACE Fastrak during single leg stance (baseline oscillation) in two foot positions, flat and demi-pointe. In both positions, time to resume baseline oscillation after inversion perturbation (perturbation time) of 15 degrees for the flat foot and 7.5 degrees on demi-pointe was also determined.

RESULTS

Baseline oscillation on demi-pointe was significantly smaller (P < 0.005) for the sprained group (2.5 +/- 0.5 mm) than for controls (4.0 +/- 2.3 mm). Perturbation time for the flat foot was significantly longer (P < 0.05) for the sprained group (2.2 +/- 0.4 seconds) than for controls (1.8 +/- 0.5 seconds). However, failure rate was higher (P < 0.05) among the sprained group than controls for perturbation with the foot flat and baseline oscillation on demi-pointe.

CONCLUSIONS

Findings demonstrated altered sensorimotor control in chronically unstable ankles. Those sprainers who successfully completed the tasks minimized oscillation. The impairments in the sprained group may reflect deficits in either movement detection, peroneal muscle response, or both.

The impact of chiropractic manipulative therapy on chronic recurrent lateral ankle sprain syndrome in two young athletes

OBJECTIVE

To describe two cases of abrupt resolution of chronic, recurrent, inversion sprain to ankles in young recreational athletes.

CLINICAL FEATURES

A 13-year-old, female, avid recreational soccer player with ankles that would spontaneously invert during various inconsistent points in the weight bearing gait cycle, sometimes with acute pain or sprain to the ankle. No intervention was attempted prior to her entry to the chiropractic office. A 17-year-old male avid skate- boarder and snowboarder whose left ankle routinely "gave out" into inversion upon mundane weight bearing activity, usually with pain and with dependence on wearing an ankle support when skateboarding to lessen ankle pain. The patient had used an ankle support prior to seeking chiropractic care.

INTERVENTION AND OUTCOME

High velocity, low amplitude chiropractic manipulative therapy applied to the spine, pelvis and extremity joints was the primary intervention in both cases, with particular focus on the ankle. Other procedures used included taping and orthotics, but not before the manipulation effect was noted.

CONCLUSION

High velocity, low amplitude chiropractic manipulative therapy to the spine, pelvis, and extremities, particularly at the ankle, should be considered when managing young recreational athletes with functional chronic, recurrent, ankle inversion sprains.

The Football Association Medical Research Programme: an audit of injuries in professional football: an analysis of ankle sprains

AIM

To conduct a detailed analysis of ankle sprains sustained in English professional football over two competitive seasons.

METHODS

Club medical staff at 91 professional football clubs annotated player injuries. A specific injury audit questionnaire was used together with a weekly form that documented each club's current injury status.

RESULTS

Completed injury records for the two competitive seasons were obtained from 87% and 76% of the participating clubs. Ankle ligament sprains accounted for 11% of the total injuries over the two seasons, with over three quarters (77%) of sprains involving the lateral ligament complex. A total of 12 138 days and 2033 matches were missed because of ankle sprains. More sprains were caused by contact mechanisms than non-contact mechanisms (59% v 39%) except in goalkeepers who sustained more non-contact sprains (21% v 79%, p<0.01). Ankle sprains were most often observed during tackles (54%). More ankle sprains were sustained in matches than in training (66% v 33%), with nearly half (48%) observed during the last third of each half of matches. A total of 44% of sprains occurred during the first three months of the season. A high number of players (32%) who sustained ankle sprains were wearing some form of external support. The recurrence rate for ankle sprains was 9% (see methodology for definition of reinjury).

CONCLUSION

Ankle ligament sprains are common in football usually involving the lateral ligament complex. The high rate of occurrence and recurrence indicates that prevention is of paramount importance.

Unilateral Multiaxial Coordination Training and Ankle Kinesthesia, Muscle Strength, and Postural Control

Objectives:

To determine the physiological adaptations that might occur with a 4-week unilateral multiaxial training program in lower leg kinesthesia, peak torque, and postural control.

Study Design:

True experimental pretest-posttest control-group design.

Setting:

Research laboratory.

Subjects:

26 healthy, active subjects (14 men, 12 women).

Interventions:

Subjects were assigned to an experimental or control group. The experimental group performed multiaxial coordination training 3 days/wk for 4 weeks.

Main Outcome Measures:

Both groups were tested 3 times, pretest and 2 and 4 weeks after training was initiated. Outcome measures included conscious appreciation of ankle kinesthesia, eversion and dorsiflexion isokinetic peak torque, and static and functional postural control.

Results:

Results revealed a significant Group × Test interaction only for inversion kinesthesia.

Conclusions:

Four weeks of multiaxial coordination training did not significantly improve any of the dependent variables in healthy individuals. Further research should consider the effects of such a program on injured subjects.

Reposition sense of lumbar curvature with flexed and asymmetric lifting postures

STUDY DESIGN

Reposition sense of lumbar curvature was assessed as a function of trunk flexion, trunk asymmetry, and target lumbar curvature using a repeated-measures design and an active-active proprioception paradigm.

OBJECTIVE

The objectives of the research were to measure the ability of the subjects to sense and control the lumbar curvature in different lifting postures and to see if error in the lumbar curvature would increase in high-risk postures.

SUMMARY OF BACKGROUND DATA

The risk of low back disorders (LBDs) is related to trunk posture, with greater risk reported in flexed and asymmetric trunk positions. Spinal posture, including trunk position and lumbar lordosis, influences spinal stability. Hence, the ability to accurately sense and control spinal curvature may be an important factor in the control of LBD risk.

METHODS

Eleven subjects were trained to assume specified lumbar curvatures using visual feedback. The ability of the subjects to reproduce this curvature without feedback was then assessed. This procedure was repeated for different trunk postures, including flexion and asymmetry, and with different target lumbar curvatures.

RESULTS

These measurements demonstrated reposition error was increased in flexed trunk positions but was unchanged with trunk asymmetry. This increase in reposition error with flexion was diminished when the target posture and lumbar curvature were highly flexed and kyphotic.

CONCLUSIONS

This research suggests that it may be difficult to control spinal curvature in flexed positions, leading to an increased risk of injury. For jobs in which flexed working postures are unavoidable, therefore, it is important to minimize potentially unstable events such as slipping or shifting loads to avoid injury.

Mechanically induced ankle inversion during human walking and jumping

A new method to study sudden ankle inversions during human walking and jumping is presented. Ankle inversions of 25 degrees were elicited using a box containing a trap door. During the gait task, subjects walked at a speed of 4 km/h. At a pre-programmed delay after left heel strike, an electromagnet released the box on the treadmill. This delay enabled the subject to step on the box without having to change the walking cadence. During the jumping task, subjects jumped from a 30 cm high platform on the box in a standardised way. In both tasks 20 stimulus and 20 control trials were presented randomly. The average tilting velocity of the trap door during the stimulus trials was 403 degrees /s during the walking task and 595 degrees /s during the jumping task. For the control trials a tilting of 0 degrees was used. With this method it is possible to evoke reproducible ankle inversions causing characteristic EMG responses in six lower leg muscles.

Sensori-motor control of the uninjured and injured human ankle

This review focuses on the role of sensori-motor function in the healthy as well as the functionally unstable ankle. The concept functional ankle instability--a widely used term, which has no universally agreed upon definition-as well as the sources of peripheral afferent information measured with different sensori-motor tests are discussed. The protective mechanisms against sudden ankle inversion are reviewed, and models that directly connect deficits in kinaesthesia and peroneal reflex reaction to an increased risk of sustaining unprovoked ankle inversion injuries are presented.

Seven years follow-up after ankle inversion trauma

During one year all ankle inversion injuries seen at the acute ward of our institution were divided into grades of severity and classified according to the maximal area of tenderness at the time of clinical examination. Seven years later 648 of the subjects (91%) evaluated their ankle with the help of a questionnaire. Location of maximal tenderness at the time of injury was: lateral fibular ligaments 61%, lateral midfoot ligaments 24%, base of the fifth metatarsal/peroneal tendons 5% and combined lesions 8%. 39% were considered minor, 46% were moderate, and 15% severe. All cases followed a functional treatment protocol. Seven years post- injury 32% reported chronic complaints of pain, swelling or recurrent sprains. 72% of the subjects with residual disability reported that they were functionally impaired by their ankle - in most cases a question of not performing sports at a desired level. 4% experienced pain at rest and were severely disabled. 19% were bothered by repeated inversion injuries - 43% of these subjects felt that they could compensate by using an external ankle support. There was no correlation between the severity of the sprain as judged at the time of injury and the frequency of residual disability or between the area of maximal tenderness at the time of injury and the area of maximal pain at the time of follow-up.

A multi-station proprioceptive exercise program in patients with ankle instability

PURPOSE

The aim of the present study was to investigate the effects of a 6-wk multi-station proprioceptive exercise program that is easy to integrate in normal training programs.

METHODS

Patients with chronic ankle instability were used, and results of three testing procedures before and afterward were compared: joint position sense, postural sway, and muscle reaction times to sudden inversion events on a tilting platform. A total of 30 subjects with 48 unstable feet were evaluated (exercise group: N = 31; control group: N = 17).

RESULTS

In the exercise group, the results showed a significant improvement in joint position sense and postural sway as well as significant changes in muscle reaction times.

CONCLUSION

Based on the present results, a multi-station proprioceptive exercise program can be recommended for prevention and rehabilitation of recurrent ankle inversion injuries.

Control of acceleration during sudden ankle supination in people with unstable ankles

STUDY DESIGN

Comparative study of differences in functional control during ankle supination in the standing position in matched stable and unstable ankles (ex post facto design).

OBJECTIVES

To document acceleration and deceleration during ankle supination in the standing position and to determine differences in control of supination perturbation between stable and unstable ankles.

BACKGROUND

Repetitive ankle sprain can be explained by mechanical instability only in a minority of cases. Exercise therapy for ankle instability is based on clinical experience. Joint stability has not yet been measured in dynamic situations that are similar to the situations leading to a traumatic sprain. The process of motor control during accelerating ankle supination has not been adequately addressed in the literature.

METHODS AND MEASURES

Patients with complaints of ankle instability (16 unstable ankles) and nonimpaired controls (18 stable ankles) were examined (N = 17 subjects, 10 women and 7 men). The average age was 23.7 +/- 5.0 years (range, 20-41 y). Control of supination speed was studied during 50 degrees of ankle supination in the standing position using accelerometry (total supination time and deceleration times) and electromyography (latency time). Timing of motor response was estimated by measuring electromechanical delay.

RESULTS

The presence of an early, sudden, and presumably passive slowdown of ankle supination in the standing position was observed. Peroneal muscle motor response was detected before the end of the supination. Unstable ankles showed significantly shorter total supination time (109.3 ms versus 124.1 ms) and significantly longer latency time (58.9 ms versus 47.7 ms).

CONCLUSIONS

Functional control in unstable ankles is less efficient in decelerating the ankle during the supination test procedures used in our study. Our conclusions are based on significantly faster total supination and significantly slower electromyogram response in unstable ankles. The results support the hypothesis that both decelerating the total supination movement during balance disturbance and enhancing the speed of evertor activation through exercise can be specific therapy goals.

Functional instability of the ankle and the role of neuromuscular control: a comprehensive review

A review of current knowledge of the clinical syndrome of functional ankle instability is presented. Recent evidence has demonstrated that the majority of patients with functional instability of the ankle do not have mechanical hypermobility of the ankle joint. Functional instability of the ankle results from a loss of neuromuscular control. Components of neuromuscular control include proprioception, muscle strength, muscle reaction time, and postural control. Proprioceptive deficits lead to a delay in peroneal reaction time, which appears to be a peripheral reflex. Proprioception and eversion muscle strength improve with the use of passive supportive devices. Balance and postural control of the ankle appear to be diminished after a lateral ankle sprain and can be restored through training that is mediated through central nervous mechanisms. Methods of detecting deficits in neuromuscular control are presented along with rehabilitation techniques to treat functional instability of the ankle.

Effect of ankle disk training combined with tactile stimulation to the leg and foot on functional instability of the ankle

Twenty-two university students with unilateral functional instability of the ankle participated in this study. They were randomly assigned to one of two experimental groups. Subjects in both groups were trained to stand on the affected limb on an ankle disk. In group 1, two pieces of 1-cm wide nonelastic adhesive tape were applied to the skin around the lateral malleolus from the distal third of the lower leg to the sole of the foot before the training sessions. Subjects in group 2 participated in the training sessions without the application of the adhesive tape. Training was performed for 10 minutes a day, five times per week, for a period of 10 weeks. Subjects were tested for postural sway while standing on the affected limb before, during, and after the training period. In group 1, postural sway values decreased significantly after 4 weeks compared with the pretraining performance, and they were within the normal range after not more than 6 weeks of training. In group 2, the values did not improve significantly compared with the pretraining performance until after 6 weeks of training, and they were not within the normal range until after 8 weeks of training. The findings suggest that the 2-week earlier correction of postural sway in group 1 was due to an increased afferent input from skin receptors that were stimulated by the traction of the adhesive tape.

The Effects of External Bracing on Joint Position Sense Awareness for the Chronically Unstable Ankle

Context:

The effect of externally bracing chronically unstable ankles on joint position sense awareness has had limited study yet is clinically relevant.

Objective:

To determine active joint position sense awareness, effects of bracing, and differences between flexible and semirigid braces.

Design:

Between-ankle-group (chronic and healthy), repeated-measures, including brace condition for the joint position of 15° inversion from subtalar neutral.Setting:Research laboratory.

Participants:

24 subjects with healthy and 12 with chronically unstable ankles.

Main Outcome Measures:

Blindfolded subjects attempted to find a passively placedjoint position under conditions of unbraced, flexible, and semirigid braced. A 3-way repeated-measures ANOVA and post hoc Tukey test for significant interaction effects were conducted.

Results:

Significant main effects were observed for ankle status, brace, and gender, but no significant interaction effects.

Conclusion:

Chronically unstable ankles have greater error in joint position sense awareness. However, this deficit might be reduced by using an external semirigid brace.

Functional instability following lateral ankle sprain

Lateral ankle sprain (LAS) is an extremely common athletic injury. Despite extensive clinical and basic science research, the recurrence rate remains high. Functional instability (FI) following LAS is hypothesised to predispose individuals to reinjury because of neuromuscular deficits which result following injury. This paper provides an overview of the potential causes of FI which may manifest themselves clinically. The theoretical explanations of FI are discussed, as are implications for assessment and treatment of FI following LAS. When LAS occurs, structural damage not only occurs to the ligamentous tissue, but also to the nervous and musculotendinous tissue around the ankle complex. While injury to the ligaments may result in laxity of the joints of the ankle complex, neuromuscular deficits are also likely to occur due to the injury to the nervous and musculotendinous tissue. These neuromuscular deficits may be manifested as impaired balance, reduced joint position sense, slower firing of the peroneal muscles to inversion perturbation of the ankle, slowed nerve conduction velocity, impaired cutaneous sensation, strength deficits and decreased dorsiflexion range of motion. Additionally, the abnormal formation of scar tissue after injury may lead to sinus tarsi syndrome or anterolateral impingement syndrome, which may also lead to FI of the ankle complex. Assessment of patients with LAS must address not only joint laxity and swelling, but should include examination for neuromuscular deficits as well. The treatment and rehabilitation goals must also address restoration of neuromuscular function, as well as restoration of mechanical stability to the injured joints.

Lateral ankle sprains: a comprehensive review part 2: treatment and rehabilitation with an emphasis on the athlete

This is the second part of a two-part comprehensive review of lateral ankle sprains. In the first part of our review, we discussed the etiology, natural history, pathoanatomy, mechanism of injury, histopathogenesis of healing, and diagnostic approach to acute and chronic lateral ligamentous ankle injuries. Conservative intervention and treatment of grade I-III and chronic, recurrent sprains of the lateral ankle ligaments and appropriate rehabilitation guidelines are the topics of this article. We review the use and benefit of different modalities and external supports and outline our five-phase intervention program of rehabilitation based on the histopathogenesis of ligament healing. We discuss the expected timing of recovery of the acute injury as well as the management of chronic, recurrent ankle sprains. Treatment of acute ankle sprains depends on the severity of the injury. Conservative therapy has been found to be uniformly effective in treating grade I and II ankle sprains. Some controversy exists regarding the appropriate treatment of grade III injuries, particularly in high-level athletes. Our belief is that the majority of these patients may also be treated well with conservative management. Other options for the management of grade III sprains will be briefly discussed at the end of this article.

Lumbosacral position sense during pelvic tilting in men and women without low back pain: test development and reliability assessment

STUDY DESIGN

A single group test-retest design to evaluate the reproducibility of lumbosacral position sense measurements.

OBJECTIVES

To develop a measure of position sense in the lumbosacral area and to determine test-retest reliability.

BACKGROUND

Proprioception, muscle control, and coordination training could be the key issues in resolving neuromuscular dysfunction in patients with low back pain, but there are no standard ways to assess these parameters.

METHODS AND MEASURES

A piezoresistive accelerometer attached to the skin over the sacrum was used to research the repositioning accuracy of active pelvic tilting, between days, of 14 young nonimpaired subjects (20 to 26 years of age) in standing.

RESULTS

The mean absolute error for repositioning accuracy (the difference between criterion and matching positions) was 1.81 degrees (+/- 0.85). The intraclass correlation coefficient between measurements obtained on days 1 and 2 was moderate (R = 0.51). The average standard error of measurement associated with the intraclass correlation coefficient was 0.5 degree (95% confidence interval = +/- 0.99 degree).

CONCLUSIONS

These findings suggest that the proposed test is sensitive with moderate test-retest reliability to examine lumbosacral position sense in healthy subjects. Further adjustments in the testing protocol are needed to improve the test-retest reliability.

The effect of supervised rehabilitation on strength, postural sway, position sense and re-injury risk after acute ankle ligament sprain

The effect of an early rehabilitation program, including postural training, on ankle joint function after an ankle ligament sprain was investigated prospectively. Ninety-two subjects, matched for age, sex, and level of sports activity, were randomized to a control or training group. All subject received the same standard information regarding early ankle mobilization. In addition, the training group participated in supervised physical therapy rehabilitation (1 h, twice weekly) with emphasis on balance training. Postural sway, position sense and isometric ankle strength were measured 6 weeks and 4 months after the injury, and at 12 months re-injury data were obtained. In the training group, there was a significant difference between the injured and uninjured side for plantar flexion (P < 0.01), eversion (P < 0.01) and inversion (P < 0.05), but not for dorsiflexion at 6 weeks. In the control group, there was a significant difference between the injured and uninjured side for plantar flexion (P < 0.01), eversion (P < 0.01), inversion (P < 0.01), and dorsiflexion (P < 0.05) at 6 weeks. Postural sway, but not position sense, differed between the injured and uninjured side in both groups (P < 0.01) at 6 weeks. The side-to-side percent differences were similar in both groups for all variables (P > 0.05) at 6 weeks, and there were no side-to-side differences at 4 months in either group. In the control group, 11/38 (29%) suffered a re-injury, while this number was only 2/29 (7%) in the training group (P < 0.05). These data showed that an ankle injury resulted in reduced ankle strength and postural control at 6 weeks, but that these variables had normalized at 4 months, independent of the supervised rehabilitation. However, the findings also demonstrated that supervised rehabilitation may reduce the number of re-injuries, and therefore may play a role in injury prevention.

Ankle sprains and other soft tissue injuries

Lateral ankle sprains are the most frequently encountered injuries in sports. In the evaluation of lateral ankle injury, one should consider all soft tissue structures (i.e., peroneal tendons, ligaments of the ankle, subtalar joints, around the lateral ankle). The treatment of most ankle sprains has evolved from immobilization to functional rehabilitation. Many patients with ankle sprains return to their previous activities. A few patients are left with pain and residual instability after conservative treatment; thus, the question of when to operate on acute severe ankle sprain remains controversial. The other challenge physicians face is the problem of persistent lateral ankle pain after sprain. This condition may be due to intra-articular or extra-articular pathology (i.e., soft tissue lateral ankle impingement, osteochondral lesion, or partial peroneal tendon tear). Diagnosis can be made with careful history, physical examination, and appropriate ancillary studies. Only proper diagnosis can lead to uncompromised, undelayed patient care.