Abstract
Background:
Taping is an effective temporary therapy for improving hallux valgus (HV) in adults. Although HV has been demonstrated to impair postural balance, there is a lack of information about how corrective taping affects balance and gait patterns in adults with HV deformity.
Methods:
Eighteen middle-aged female patients (average age, 53.5 years) with HV were included. Corrective tape was applied to correct HV angulation. A series of balance and gait stability tests were performed before applying tape and 1 hour after the tape was applied with a Balance Master computerized posturography device. The study involved the following tests: modified clinical test of sensory interaction and balance (mCTSIB), unilateral stance (US), limit of stability (LoS), step up/over (SUO), and walk across (WA) tests.
Results:
No significant difference was found between the no-tape and taped condition in the static balance mCTSIB and US tests (P > .05). The taping intervention resulted in significant improvement in the dynamic balance measures for the LoS test’s backward reaction time and left maximum excursion (P < .05), a significantly higher impact index bilaterally in the SUO assessment (P < .05), and an increase in step width mean and variability in the WA test (P < .05).
Conclusions:
Taping for correcting HV angulation had negative acute effects on dynamic balance in the SUO and WA tests and positive effects in the LoS test.
Clinical Relevance:
Corrective taping, although a form of conservative treatment for hallux valgus, has been insufficiently studied in terms of effects on balance. Our results show that taping, as an acute effect, may impair balance in middle-aged adults when walking or ascending and descending stairs.
Keywords
Introduction
Hallux valgus (HV) is a common progressive foot deformity that results in abnormal angulation, rotation, and lateral deviation of the great toe at the metatarsophalangeal joint. HV is present if the angle is more than 15 degrees in either foot. 13 HV has been shown to be strongly associated with age and female sex. 37 Prevalence was reported to be 28.4% in adults, 37 but as high as 74% in the elderly population. 28 HV has been reported to cause foot pain and functional disability7,36 and demonstrated to negatively affect balance, mobility, and ambulation,27,39 impair gait patterns 29 and cause poor postural stability, and increase the risk of falling.27,39 Pathomechanical consequences on foot function of patients with HV have been associated with its effect on foot kinematics.14,22 Deschamps et al found alterations in sagittal plane kinematics of the foot in their HV population. They reported increased dorsiflexion/adduction at the first tarsometatarsal joint, which results in an earlier onset of the dorsiflexion movement for the first hallux. 14
The impact of foot pathologies, such as hallux rigidus and posterior tibial tendon dysfunction, on temporospatial parameters of gait has been previously discussed in the literature. Increase in stance duration and cadence, decrease in walking speed and stride length, has been reported.9,33 It has been suggested to consider treating foot pathologies like hallux valgus, lesser toe deformities, flatfoot, or tendon dysfunction in adults because foot problems may compromise function, leading to mechanical instability. As a consequence, they may negatively affect balance during standing, walking, and daily living activities, especially in old age.30,31
Conservative treatment options for HV deformity include exercise, taping, modification of footwear, orthoses, and physical therapy modalities. 4 Although there is limited evidence regarding the effectiveness of conservative treatment approaches, 16 taping has been reported to decrease pain and disability in HV deformity.3,22 Bayar et al also found that taping has beneficial effects on walking ability in patients with HV. 3
Motion analyses systems, force plates, and posturography devices were previously used for assessing foot deformities based on several parameters such as function, postural stability, gait patterns, foot kinematics, and balance in adults.14,29,30 Computerized posturography (CP) systems provide useful information about balance and postural control during stance- and gait-related functional tasks in middle-aged and elderly people. 18 Age-related declines in postural stability, which is a serious problem for older adults at risk of falling, is measured by CP. 24 In addition, the associations between foot deformities and poor performance in balance and functional tests in elderly people have been emphasized, 29 yet information regarding the effects of mechanical correction of deformity on posture and gait parameters are limited.
Owing to its high prevalence in the aging population and its negative effects on gait and balance, further research should focus on the impact of HV deformity correction on gait and balance in the elderly population. We hypothesized that a short-term implementation of corrective taping would positively affect the postural balance and gait in patients with HV. Therefore, the purpose of this study was to investigate the acute effects of corrective HV taping on gait and balance parameters in middle-aged patients with HV deformity.
Methods
Patients and Study Protocol
This study was approved by the local ethical committee of our university. All patients signed an informed consent form and were informed about the intervention and the purpose of the study.
Eighteen middle-aged patients (45-64 years) diagnosed with bilateral HV deformity (presenting an HV angle greater than 15 degrees) who came to our department for treatment were included in the study. Sensory thresholds for the plantar surface of the foot were examined using the Semmes-Weinstein monofilament test before study entry, and only patients with a normal sensory threshold were included in the study. The normal sensory detection threshold for the plantar surface of the foot was accepted as the 3.61 monofilament. 6 Patients were excluded if they refused to participate in the study, underwent osteoarticular surgery on the foot, had endoprosthesis of a knee joint, had neurologic or systemic disease (such as rheumatoid arthritis, systematic lupus erythematosus, and diabetes mellitus), had degenerative bone or joint diseases or neuromuscular imbalance, had other obvious deformities in the foot that might affect the results of the study, or received any chemotherapy or radiotherapy treatments previously.
Of 72 patients who were potentially eligible for the study, 18 (25%) met the initial inclusion criteria. The excluded subjects were due to systemic disease (6 patients), previous radiotherapy (1 patient), inability to visit the clinic for the 3-hour posturographic examination (18 patients), age over 64 years (9 patients), and age below 45 years (12 patients). Eight patients declined to participate in the study. A total of 18 female patients with bilateral hallux valgus deformity completed the tests. A flow diagram is shown in Figure 1. Baseline characteristics of the patients are shown in Table 1.
Flow diagram for participant enrollment, post-intervention and analysis.
Characteristics of the Patients. a
Abbreviation: SD, standard deviation.
Change values are expressed for mean (SD).
P < .05, significant difference between no tape and taped conditions.
Measurements included the assessment of balance during static conditions, functional tasks, and gait using the NeuroCom Balance Master computerized posturography device (Neurocom International, Inc, Clackamas, OR). 34 Retest reliability of the tests has previously been established. 32
Outcome Measures
Demographic data of the patients, including age, body weight, height, and medical history, were recorded at the baseline evaluation. Subsequently, the first metatarsophalangeal angle was measured at baseline and following taping using a toe goniometer in no-taped and taped conditions according to Lamur et al and recorded in degrees. 23
The Balance Master device consisted of a fixed force plate (18 × 60 inches) that recorded data with the aid of piezoelectric crystal transducers (Figure 2). Force-plate data included the X (±0.08 cm) and Y (±0.25 cm) positions of the center of vertical force and total vertical force (±0.1 N) at a sampling rate of 100 Hz. With this system, the transducers transmitted pressure to the computer every 10 milliseconds; then, the dynamic center of gravity of the subject was calculated, and the sway velocity during a specified time period was obtained. Sway velocity (degrees/second) measured the angular change of the center of gravity per unit of time. The sway velocity has been an appropriate dependent measure for determining postural stability. 26
Balance Master device.
On the Balance Master, a series of tests were administered, including a modified clinical test of sensory interaction and balance (mCTSIB), unilateral stance (US), limit of stability (LoS), step up/over (SUO), and walk across (WA) tests. 34 In this study, a number of balance and gait stability measurements were used to evaluate the domains of balance response to changes after the taping intervention.
Patients were instructed to remove their shoes and step on to the platform. The measurements were made under 2 conditions: either untaped or with the application of corrective HV taping. The 2 taping conditions were randomly assigned an interval of 1 hour for each of the conditions. But the order of tests was the same in each patient depending on the software. Pilot studies using pressure-sensitive monofilaments showed that adhesive tape initially increased sensitivity to touch around the joint, but cutaneous sensibility returned to baseline within 5 minutes of tape removal. 5 Therefore, we decided to allow 1-hour intervals between taping conditions so that patients could rest while sitting and carryover effects of tape on cutaneous sensation could be minimized. There was approximately a 2-minute rest period between tests.
All assessment protocols took approximately 3 hours per person, depending on the patient’s ability to follow instructions and other conditions: 15 minutes for taping application, 1 hour for rest, and 45 minutes for each testing condition. The duration of each test was standardized in the software. The same procedure was applied for all tests. Each test procedure was explained to the patients individually and shown via video on the software program. All procedures were conducted by the first author, who is a physiotherapist. Participants were asked to report any adverse symptoms while wearing tape and the investigator inspected the foot after tape removal. No patient complained of fatigue or adverse symptoms during or after the test.
Tests
Balance measures
The following clinical static and dynamic balance measures were used. Tests of static balance required movement of a person’s center of mass within a stationary base of support; examples of static balance tests include the mCTSIB test and US test. These assessments, however, did not represent all the domains of balance that are needed to perform dynamic, functional activities. In tests of dynamic balance, both the center of mass and the base of supports are moving. The LoS test was used to assess dynamic balance. The SUO test (ascending and descending stairs) and the WA test (gait) was used to assess dynamic balance in functional activities. 40
mCTSIB test
The mCTSIB was a simplified derivative of the sensory organization test that provided objective evidence of sensory dysfunction. This test was designed to assess how well an adult was using sensory inputs when 1 or more sensory systems were compromised. The test examined postural sway velocity during the 4 sensory conditions in standing position: eyes open firm surface in “Condition 1”; eyes closed firm surface in “Condition 2”; eyes open foam surface “Condition 3”; and eyes closed foam surface in “Condition 4.” In condition 1, all 3 systems regarding vision, somatosensory, and vestibular were available for maintaining balance. In condition 2, vision was removed and the subject relied on the somatosensory and vestibular systems to balance. In condition 3, somatosensory information was reduced and the subjects used vision and the vestibular system to balance. In condition 4, vision was removed and somatosensory information was reduced. The subject must have used vestibular inputs to balance. In the test scores, composite sway was the mean sway velocity averaged over the 4 conditions.
US test
The US test quantified the velocity of postural swaying with patients standing on either the right or left foot on the force plate under 2 conditions: eyes open and closed. Each trial lasted for 10 seconds and was performed 3 times. In this study, the results of the US test were recorded as degrees per minute, and higher values indicated an unstable unilateral stance.
LoS test
The LoS quantified the maximum distance the patient could intentionally displace their center of gravity (COG) in the 4 cardinal directions and the 4 diagonal directions, and maintain stability at those positions. For this test, the patient stood with her feet in a standard position, viewed a cursor display of her CoG position, and oriented herself so that the CoG cursor coincided with a target representing the center of the LoS area. A second target was then placed at a predetermined distance from the center relative to the LoS boundary. The patient moved the CoG cursor on command as quickly and as accurately as possible to the perimeter target and held the perimeter position for 5 seconds. In this study, the task was repeated for a total of 4 perimeter targets, representing the 4 cardinal directions (forward, backward, left, and right). The measurements included reaction time, that is, the time between the signal to move and the initiation of movement (seconds), and maximum excursion, that is, the furthest distance traveled by the CoG away from the upright stance (percentage of limits of stability). Faster reaction times (lower scores) and larger maximum excursion (higher scores) indicated a better performance.
SUO test
For the SUO test, the patient stood in front of a raised platform, stepped onto the platform with the leading leg, and swung the opposing leg over the platform and down onto the surface on the opposite side. The maneuver was performed as quickly as possible and repeated 2 times each with the left and right lower extremities. The following performance measures were calculated for each extremity: lift-up index and impact index. The lift-up index was defined as the maximum concentric lifting force (percentage of body weight) exerted by the leading leg. The impact index, expressed as a percentage of body weight, represents the maximum vertical ground reaction force generated by the contact of the leading extremity on the force plate.
WA test
The WA quantified characteristics of gait as the patient walked across the length of the force plate. During the WA test, which assessed stability during gait, the patient stood approximately 1 m before the start of the long plate and then walked at her comfortable walking pace using her usual indoor gait across the long plate. Step width, step length, and speed were the performance measures for the WA test (Figure 3).
Data example of test protocol of the Walk Across Test. The test quantifies characteristics of gait as the patient walks across the length of the force plate. Measured parameters are average step width, average step length, and speed.
Study Interventions
Taping
A nonallergenic and nonelastic corrective taping was applied (Protape, 38 cm × 10 m; Norway) to correct the HV angulation. The first strip was attached around the distal toe at the base of the toenail and another strip was attached parallel to the midline of the medial aspect of the foot. A third strip was then applied and joined the first 2 strips distally to proximally, maintaining the hallux in the midline position (Figure 4). 1 The taping technique was applied by the second author. The order of the taped and no-tape condition was randomized for each patient.
(A) Hallux valgus angulation. (B) Correction of hallux valgus angulation with athletic tape.
Statistical Analysis
Statistical power analyses based on the pilot study with 8 patients (for primary outcome measurement of dynamic balance in a standing position) were used to determine the optimum sample size. The minimum necessary sample size was determined as 18 subjects with a 20% drop-out rate and 80% power. Data analysis was completed using SPSS software, version 18.0, for Windows (SPSS Inc, Chicago, IL). Data are expressed as means (standard deviations). The alpha level for determining statistical significance was set at .05. Data were found to show normal distribution on the Kolmogorov-Smirnov test. A paired Student t test was used to examine whether the differences between scores in the taped and no-tape conditions were statistically significant.
Results
The average age was 55.5 (range, 45–64) years. After the taping intervention, a significant improvement in the average HV angle was found of 23.2 (6.23) degrees (P < .001). Tables 2 and 3 show the post-taping changes on the posturography tests. No significant difference between the no-tape and taped condition was observed in the performance of static standing balance for the mCTSIB and US tests (P > .05). However, there was significant improvement after the taping intervention in the following dynamic balance measures of the LoS: backward reaction time (P = .024) and left maximum excursion (P = .007). The SUO assessment had a significantly higher impact index (P = .038 for the left leg and P = .009 for the right leg) in the taped condition compared with the no-tape condition. The WA test revealed an increase in step width (P = .004).
The Results of Modified Clinical Test of Sensory Interaction for Balance Test, Walk Across Test, Unilateral Stance Test and Step Up/Over Test. a
Abbreviations: CTSIB, Clinical Test of Sensory Interaction for Balance; SD, standard deviation.
Change values are expressed for mean (SD).
P < .05, significant difference between no tape and taped conditions.
The Results of Reaction Time and Maximum Excursion of Limit of Stability Test. a
Abbreviations: MXE, maximum excursion; SD, standard deviation.
Change values are expressed for mean (SD).
P < .05, significant difference between no tape and taped conditions.
Discussion
The results of this preliminary study demonstrate that although corrective taping for HV provided an important decrease in HV angulation, it did not provide additional postural stability during functional ambulation activities such as gait and ascending/descending stairs. Increased step-width mean and variability in the WA test and increased impact index in the SUO test showed that taping may have a negative effect on fall risk in patients with HV deformity. However, taping increased the limit of stability to the left direction. These were observed as acute effects of corrective taping on balance parameters in middle-aged adults with HV.
Previous studies have shown that balance performance is maintained from early adulthood until the age of 45 years after which there is a decline in performance. 15 This balance impairment with age leads to an increased incidence of falls and fractures, reduced physical activity, and limited mobility and ambulation.17,20 Feet play an important role in maintaining body balance by providing a firm base to support an upright posture, absorbing reaction forces from the ground and generating propulsion via their elastic and flexible characteristics. They also act as sensors of the ground and participate in strategies of body balance. 10 In feet, the morphological, biomechanical, and functional changes with age, such as foot deformities and alterations in ankle flexibility, plantar tactile sensation and strength of the toe plantarflexor muscles, have been reported as significant independent predictors of balance and functional ability in elderly populations.27-30 HV is one of the foot deformities that can impair foot adaptation to the ground and create balance problems.14,29,30 Therefore, if possible improving balance and postural stability in patients with HV during standing, gait, and daily functional activities is important, especially starting in middle age.
Taping is a treatment method for decreasing HV deformity and improving a patient’s symptoms. 3 Previously, taping was found as an effective therapy for improving the hallux valgus angle.3,21 In the present study, an average 23-degree correction was obtained in the mean HV angle of the patients in the taped condition. All participants completed the tests in this study. When asked whether they were satisfied with the taping, none reported difficulty or discomfort in completing the tests. However, 14 of them did not report any benefit. Four patients reported improvement in ease of maintaining balance.
There was no change found with taping in static balance reactions in the mCTSIB and US tests in this study. However, improvements in some parameters on the LoS test were observed. The LoS test has been a consistent and reliable dynamic standing balance test for older adults that measures a patient’s ability to voluntarily control weight shift in 4 main directions. 12 The backward reaction time and left maximal excursion improved in the taped condition. This may be explained by the biomechanical advantages of the taping, which increased the maximal distance an individual can lean in the left direction and provided better postural adjustments in the actual limit of stability without losing balance, especially in the left direction. Nevitt et al reported that a decrease in medial-lateral balance increases the risk of a sideways fall, which is most likely to result in a hip fracture. 35 Therefore, we propose that an increase in the limits of stability to the left direction as an acute effect of taping is a positive result for medial-lateral balance in middle-aged adults with HV. However, long-term taping may produce different results.
The SUO test measures postural stability during a stepping up and over movement, which serves as a predictor of stair ascending/descending activity performance. An increased impact index with taping in the SUO test was found, whereas lift up index remained unchanged in this study. During the SUO test, successful execution of the SUO required concentric and eccentric leg strength and proprioceptive control for patients to lift themselves over a 20-cm-high box. 32 Chmielewski et al 11 reported that a higher impact index of one leg might result from poor eccentric and neuromuscular control exhibited by the unstable opposite leg. In this study, a bilaterally higher impact index for the SUO test may indicate that corrective taping for HV altered neuromuscular control of the weightbearing lower extremity and reduced its ability to stabilize the moving leg during the step up/down task. Taping for HV may impair dynamic balance in stepping up and down activity in the acute term of the taping application. However Lazario et al did not find any difference in SUO test variables between fallers and non fallers in their study. 25
The WA test measures stability during gait. An increased step width with taping was shown in this study. This may indicate a decline in dynamic balance with corrective HV taping during walking. Patients reacted with a greater base of support to the acute effect of taping intervention for maintaining walking stability. However, step width variability is a commonly used parameter to determine the risk of falls in older people. Increased (either too little or too much) step width variability has been associated with falls. 8 In our study, based on the increase in standard deviation of the step width with tape application, we could say that the step-width variability increased. Increase in step width means and variability has been reported to indicate a lack of compensation for instability and thereby decreases balance performance and leads to a possible predisposition to falls. 19 Previously, a decrease in speed and an increase in step length was shown in adults with HV deformity during walking. 29 In the present study, step length and speed variables of gait did not change with taping. These findings are contrary to the claim that walking ability increases in parallel with a decrease in HV angle with 8-week taping treatments in patients with HV. 3 In addition, there was no negative effect of ankle taping on balance found in previous studies. 2 However, taping was shown to have no beneficial effect on postural control deficits in people with ankle instability. 38 Mickle et al suggested that toe deformities alter weight distribution under the foot when walking, and the relationship between toe deformities and falls is caused by changes in spatiotemporal gait parameters or impaired postural sway. 31
There were some limitations in this study. First, HV could have been categorized by the intensity of the first metatarsophalangeal angle as slight, moderate, or severe, and the results could be compared according to this classification. Second, a geriatric population older than 65 could be added to the study as another age group likely to have problems with balance. In addition, HV could be objectively evaluated using radiography, and dynamic electromyogram studies could provide detailed information about the activation patterns of foot muscles during balance tasks. This preliminary study showed the acute effects of HV taping on balance and gait in middle-aged patients. With adaptation to the taping, however, the long-term effects might be different.
Conclusion
The ability to walk safely and efficiently is essential for older people in order to reduce the risk of falling and to maintain their independence. Using corrective taping to conservatively treat HV in middle-aged adults may lead to changes in postural control during walking and stepping up and down activity, and may result in an increased risk of falls for older people. Our results suggest that further studies are needed that investigate the long-term effects of corrective taping on postural balance and gait parameters in elderly patients.
Footnotes
Author Note
The study was approved by the University of Hacettepe Research Ethics Board. The patients were informed regarding the treatment and its potential benefits as well as evaluation methods and, thereby, signed informed consent forms were obtained.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.