Foot Posture after MS and Functional Consequences

Abstract

Background: Clinical convention suggests that foot posture and movements are adversely affected by MS and cause walking difficulties but there is little objective data to support or refute these beliefs. This study explores static foot posture in people with MS and their relationship to walking disability and limitations

Materials and Methods: This is a cross-sectional study that was conducted in the multiple scoliosis specialist department of Kashani Hospital in Isfahan on 44 patients with MS with mobility limitations. The indices for determining Foot Posture Index (FPI), demographic characteristics, Expanded Disability Status Scale (EDSS), and walking scale (msws-12) were investigated.

Results: About one-third of participants had abnormal foot posture, which wasn’t associated with walking limitations. Most (80%) had a symmetrical foot posture with similar frequencies of supination (9%) and pronation (11/5%) abnormalities. There was no relationship between foot posture and walking limitation and expanding disability.

Conclusions: A minority of people with MS had abnormal or asymmetrical foot posture and equal numbers suffered pronation and supination abnormalities; these findings challenge the beliefs that underpin the clinical management of MS-related foot problems.

Keywords: Multiple sclerosis; Walking; Foot posture; Disability

Background and Aim

Multiple Sclerosis (MS) is a common cause of functional disorder in persons of able-bodied age. The female to male ratio is about 2:1. The disease is commonly divided into a relapsing remitting form and a progressive form (primary or secondary) [1].

Regaining mobility is a priority for MS survivors and rehabilitation [2]. There is extensive literature on gait abnormalities after stroke but Clinical Rehabilitation can’t information on the impact of MS on the foot. The foot is a highly complex and adaptable functional unit [3-5] and its problems are related to mobility limitations in other chronic conditions [6-8]. The shape of the foot or static foot posture is generally believed to be a significant predictor of foot function [9]. The significant relationship between foot posture and dynamic foot function, lower limb function and walking ability have been demonstrated in normal subjects and patients with musculoskeletal and neurological disorders [10-13].

Age-related changes in the static foot posture have been reported through several cross sectional studies; the older subjects have been shown to have more pronated feet compared to the younger adult population [14,15].

As the fi rst report of a programme of work to develop evidence-based interventions for foot problems after MS, we undertook a nature of foot abnormalities and the relationships between foot abnormalities, MS-related impairments and mobility limitations in people with MS. Given the lack of previous work in this fi eld, we addressed this aim by investigating fi ve prevailing beliefs that underpin clinical reasoning and decision-making [16,17].

The impairments we investigated were walking disability; .foot posture is related to walking ability – MS survivors with more severe abnormalities will have more limited walking ability.

Method and Material

The study used a cross-sectional survey design. MS survivors who could stand without assistance and were able to give informed consent were recruited from the MS services of kashani hospital. Participants were excluded if they had another mobility limiting condition or lower limb. If they were interested, the project was explained to them and the information sheet given.

After informed consent was obtained, the following were measured: static foot posture (Foot Posture Index); Expanded Disability Status Scale (EDSS Index) and walking scale (MSWS-12). All testing was undertaken in a one-off measurement session at the ward, clinic. Testing took about 10 minutes. Age, sex, height, weight were also recorded.

Static foot posture was measured in a standing position since a weight-bearing measure better represents foot function compared to non-weight bearing measures and have a high correlation with dynamic foot function [15,18]. The six item Foot Posture Index (FPI6) was selected as the most appropriate clinical measure of foot posture in people with MS. It is a six item scale that observes the posture of the rearfoot and forefoot in multiple planes, defining foot position as normal, supinated or pronated of course It is reliable, valid, and easy to use [13,19]. FPI can identify foot posture changes in pathological conditions such as neurological disorders [15] and predicts dynamic foot function, midstance posture during normal walking [13]. It is quick and easy to use in clinical settings [15] and adequate component, concurrent and predictive validity and inter and intra-tester reliability of FPI has been reported [13,19,20] and healthy older adults [21].

Assessing symmetry of foot posture: the FPI is a two-tailed scale in that a negative score Forghany et al. indicates a diff erent type of defi cit to a positive score [22].

Activity limitation and impairment were measured on admission and discharge of the rehabilitation trial using the motor sub-items of the Expanded Disability Status Scale (EDSS) score [23-26] Such findings highlight the poor sensitivity of current clinical assessment tools including the Expanded Disability Status Scale (EDSS), which is the MS-specific outcome measure most widely used in current clinical practice and experimental trials. Although scoring of the EDSS is heavily weighted towards mobility dysfunction in the middle and higher ranges of the scale, it is insensitive to subtle functional impairments at the lower end of the scale [27]. EDss divided to sub title: full ambulatory score was1-4/5 and ambulatory 5-8 [23].

Walking ability at home and in the community is an indicator of an individual’s ability to participate in activities of daily living [28] and is used to assess walking handicap [29]. Walking ability was assessed using Scale-12 (MSWS-12) is a 12-item patient-rated measure of the impact of MS on walking and patients were categorized as either household or community walkers according where they were able to walk using a self-reported questionnaire. We provide evidence that both confirms and extends the validity of inferences from scores of the MSWS-12 as a measure of the impact of MS on walking in a community-based sample of individuals with MS [24]. The MSWS-12 satisfies standard criteria as a reliable and valid patient-based measure of the impact of MS on walking [30]. The MSWS-12 satisfies standard criteria as a reliable and valid patient-based measure of the impact of MS on walking. In these samples, the MSWS-12 was more responsive than other walking-based scales [31].

However as the data was collected by one person on a single testing session this was not felt to be a critical short-coming for the current study.

Ethical approval was obtained from musculoskeletal Research center Ethic Committee of faculty rehabilitation.

SPSS version 16.0 was used to conduct statistical analyses. Our predetermined alpha level of significance was set at .05 for all statistical procedures. To determine appropriate parametric or nonparametric statistical tests, Shapiro-Wilk statistics checked the normality of distribution of the data sets. Parametric tests were employed in cases of normal distribution.

To compare the FPI in different groups, independent t-tests, paired t-tests, one way ANOVAs or nonparametric counterparts (Man-Whithney, Wilcoxon and Kruskal-Wallis, respectively) were employed. Correlations were determined using Pearson or Spearman statistics as appropriate.

Results

Fourty four MS subjects (8 men and 36 women, age 36.47±9.07 years, height 1.63±9.56 meters, weight 63.02±14.55 kilograms were recruited.

All subjects walked without any assistive device during the test.

In MS subjects, the mean score of total EDSS (3.87±1.99) and MSW (3.54±.15), EDSS: full ambulatory (%59.1) and Ambulatory Impairment %40.9). The mean score of total Right foot FPI (Most MS subjects (%59.1) showed normal foot posture on the affected side and abnormal %40.9). When there was an abnormal foot posture, pronation was more common than supination.

Right foot FPI (%6.8 of the affected feet were in the supinated range, %59.1 normal and %34.1 pronated). the mean score of total left foot FPI (abnormal %36.4 and normal %63.6), left foot FPI (%9.1 of the affected feet were in the supinated range, %63.6 normal and %27.3 pronation).

Fifteen (25%) participants had abnormally pronated feet, 16 (22%), were in the ‘abnormal’ range. Eleven (16%) were abnormally supinated. None were highly abnormal.

Most participants had a symmetrical foot posture, only 6 (13.6%) were asymmetrical.

The binary logistic regression model showed age, walking and symmetry index to be nonsignifi cant predictors (P<0.05).

There was no difference between the right and left sides of the healthy aged-matched subjects. Table 1 shows the distribution of participants across the five categories of symmetry FPI labeled as relative foot types and asymmetry FPI.

  

    
Symmetry and Asymetry FPI (Relative    foot types)
    
Frequency (n)
  
  

    
Symmetrical
    
both normal
    
24(54.5 %)
  
  

    
both abnormal pronated
    
11(25%)
  
  

    
both abnormal supinated
    
3(6.8%)
  
  

    
Right more pronation
    
5(11.4%)
  
  

    
Right more supination
    
1(2.3%)
  
  

    
Asymmetrical
    

    
6(13.6%)
  
  

    
Total
    

    
44(100%)
  

Table 1: