INTRODUCTION AND BACKGROUND OF THE STUDY;
Chronic heel pain is the most common condition, accounts about 15 percent in population (Rome, 2005). Chronic plantar heel pain likely present in conditions plantar fascitis, subcalcaneal bursitis, neuritis, subcalcaneal spur (Narvaez et al, 2006). The common cause of chronic plantar heel pain is plantar fascitis.pain may occur along the entire attachment of the plantar fascia or limited usually on the inferior medial aspect of the calcaneum,the bony prominence act as the origin for the plantar fascia and the weakest point of the fascia in which the fibres themselves are in highly tensile stress. Pain in the morning is due to the inflammation of the plantar fascia, in rest the inflammatory exudates will settle while, initiating the movement after prolong rest produce pain (Riddle et al, 2003).
subcalcaneal bursa present on the posterior aspect of the calcaneum behind the Achilles tendon and inflammation of the bursa produced pain on the posterior aspect of the heel in subcalcaneal bursitis .subcalcaneal spur is due to plantarfascitis, healing process occurs in damaged fascia as blood rush up to the injured area, calcium in the blood is deposited to produce exostoses of the calcaneum spur. Last about neuritis is the inflammation of the nerve with sensory loss and pain (Rome et al, 2000).
About Gender females more common to get chronic plantar heel pain than male due overweight that stress the foot , broad pelvis increased Q angle will causes increase in physiological genuvalgum it further causes pronation of the foot. Size of the foot compared to male is small, in smaller surface area it as to bear more force stress the soft tissue and leads to pain as a result of damaged tissues. It is very common among the adolescent according to the survey (Ozdemir et al, 2003).The etiological factors from the literature are limited dorsiflexion of ankle, excessive pronation of the foot, reduced calf strength, reduced leg length discrepancy, obesity, prolong standing, running in distance, improper shoes, old age. All this factors shows the limitation of evidence (Buchbinder, 2004).
Causative factor for the chronic plantar heel pain was not understood clearly as each condition have different etiological factor .Evidence and research to hypothesis the etiological factor of the chronic plantar heel pain up-to-date lacks . Lack of evidence and poor understanding of the causative factor on chronic heel pain, authors as addressed this paper (Irving et al, 2006). Authors selected the common causative factor for chronic heel pain that is assessed in the clinic as a routine and in literature for evidence to associate the common etiological factor with chronic plantar heel pain.
Authors did research work in the past on obesity in non athlete and found its association with chronic plantar heel pain. The case group data was of this paper as been originated from the previous work of randomised control trial, examining the effect of topical wheatgrass cream on chronic plantar heel pain (Young et al, 2005). This paper based on examine whether the etiological factors obesity, pronated foot, reduced calf muscle endurance ,decreased angle of dorsiflexion are the risk factor in producing the chronic heel pain .
HYPOTHESIS;
Hypothesis being tested in this research paper to examine the association of obesity, increased pronated foot, decreased ankle dorsiflexion, reduced calf muscle endurance with chronic heel pain.
DISCUSSION ON DESIGN;
Case-control study with 80 participants in each group.Slighlty higher percentage of female than male, because females more prone for chronic plantar heel pain. Inclusion criteria participant with pain on the plantar aspect of the foot and early morning pain and pain produced after prolong rest. Pain was the only diagnostic tool for confirming the chronic plantar heel pain at least any one of the imaging techniques such as radiograph could be included.
In inclusion criteria pain on the heel in the plantar region includes plantarfascitis, calcaneal spur but in subcalcaneal bursitis pain produced on the posterior aspect of the heel. Authors could have analysed one particular condition which is more common like plantarfascitis or divided the case group into subgroups based on the conditions that comes under chronic plantar heel pain. Further the subgroups are tested separately whether the hypothesised
To examine obesity as the causative factor for chronic plantar heel pain, in inclusion criteria participants with the body mass index above 30 kilogram/metre square. Participants should inform whether their gained weight after the heel pain or before the pain started, because heel pain leads to lack of physical activity that leads to obesity and the results may not be strongly appropriate.
About age group chronic plantar heel pain was common in adolesant.Age group for this study was chosen between 20-82years and people above the age of sixty will undergo normal physiological aging process that may result in reduced strength of the muscle, decreased range of motion as synovial fluid changes In the joint produce friction. Postural changes occurs in the whole body includes the foot. Age limit could be considered in the inclusion criteria to make accuracy in the result.
Exclusion criteria are pregnancy as the body gains weight in gestation period, skin lesion restricts the measurements, seronegative arthritis involvement of the joints and reduce range of motion. Participants taken steroid injection increases the body weight and participants under conservative management or taken treatment before eight weeks reduces the pain all this factors interfere with the accuracy of the result and outcome measures.
The measurements are taken by two different researches for both the group that may show a slight variation in the data. It could be better if the measurements are taken by the same person or pilot study would have been done to correlate between the two investigators. Randomised case control study was approved by the faculty of Health Sciences Human Ethics of La Trobe University. Researches took the informed consent from all the participants.
DISCUSSION ON METHODOLOGY AND TECHNIQUES;
To examine the risk factors obesity, pronated foot, decreased ankle dorsiflexion, reduced calf endurance .methods used are foot posture index ,body mass index to analyse obesity ,dorsiflexion lunge test to measure ankle dorsiflexion range of motion, occupational stress test to find out activity that produce heel pain, standing heel raise test to examine calf endurance.
Foot posture index measure the static foot posture, and pronated foot in bilateral stance. It is a scale with six criteria that are more relevant to be tested for the pronated foot. Foot posture is measured by clinical techniques like arch height, footprint indices, naviculardrop and drift, rear foot plane motion and foot posture index. When compared with other techniques Foot posture index test is the most reliable, validity questionable, easy and fast to use. Foot posture index test analyse posture in frontal, saggital, transverse plane. This case control study participants were examined by an experienced podiatrics shows the result accuracy. Analysing the foot posture is appropriate to find out whether the pronated foot are the risk factor for chronic heel pain (Redmond et al, 2005).
BMI is a relevant measuring technique to examine obesity. It is a world wide used measurement which incorporates height in meter square and weight in kilograms.BMI easily measurable and accurate one measuring. BMI analyse the whole body when compared to other techniques such as waist hip ratio, waist measurement concentrate on the abdominal fat explained by national institute of health.
Dorsiflexion lunge test find out the range of motion of the dorsiflexion of the ankle, it is a reliable test in weight bearing. Occupational stress test as prolonged standing mentioned causative factor for heel pain in the literature. Occupational stress shows limitation as the activity of the participants is reduced by pain and there as to answer based on the previous work (Noyes et al, 1991).
Standing heel raise test to analyse the strength of the calf, to examine whether the reduced calf muscle strength as a causative factor for chronic heel pain (Ross et al 2000).
DISCUSSION ABOUT STATISTICAL ANALYSIS AND RESULTS;
Statistical analysis two independent sample tests compare the mean of the randomised case-control group. To find the significant difference between the two groups, data collections are mean value, so t test is the suitable test to compare the mean value of the two groups in normal distributed data (Menz, 2004). Result of the t test shows body mass index significant p value .005 less than .05 and the mean value of the BMI in case group greater than control group. The null hypothesis rejected, there is a significant difference in the two groups in body mass index.
Foot posture index shows p value .004 less than .05 and again the mean value of FPI in case group higher than the control group. In this case also null hypotheses are rejected and show the significant difference between two groups. Two independent sample t tests shows greater significant difference, it states that two group as difference in the body mass and foot mass index. This supports the hypotheses being tested by the researcher. Participants with chronic plantar heel pain case group should differ from the control group in obesity and pronated foot to support that, these two factors may be the risk factor for chronic plantar heel pain.
Standing heel raise test shows p value .050 greater than .05 the null hypothesis is accepted and there is no significant difference between the two groups regarding this test and shows the negativity of the hypothesis being tested .Standing heel test indicates the endurance of the calf muscle, the test result shows that there is no difference in the calf muscle strength between the two groups. Researches as taken data based on the limb affected more by pain but in the outcome measures bilateral leg measurement was taken.Dorsiflexion lung test p value was mentioned as less than .001 the null hypothesis is rejected .It shows a less significant difference between the two groups.
Man Whitney test used for occupational rating scale since, data are recorded as median value and the data are not normally distributed for occupational rating scale. No significant difference was found out between the case controls groups in the result of test as the p value was highly greater than .05 exception of weight carried P value .003,it accept the null hypothesis .Authors included occupational stress as a causative etiological factor but the statistic reports shows negativity. To analyser the co morbidity variables association chi-square test was carried out. In the table significant p value for chi-square was not mentioned, so could not comment on it. Authors explained there is no significant difference in the group with co morbidity.
Multiple variate analysis Logistic Regression test carried out to find whether the pronated foot, body mass index, decreased ankle of dorsiflexion, as relation with chronic heel pain. Before doing logistic regression test researches as documented foot posture index as pronated foot, ankle dorsiflexion as excessive or not and body mass index as obesity and used non significant chi-square test to avoid the correlation between the causative factors. Pronated foot shows p value is .002 less than .05 the null hypothesis rejected and shows the relation of pronated foot with chronic heel pain.
Excessive dorsiflexion shows p value .088 greater than .05, it accepts the null hypothesis, there is no significant relation found with chronic plantar heel pain. It states indirectly decreased ankle dorsiflexion that was tested as a chronic plantar heel pain. About excessive dorsiflexion, the hypothesis been tested is the decreased dorsiflexion of the ankle and authors worked on excessive dorsiflexion. Obesity shows value of .004 which is less than .05, null hypothesis is rejected and there is a significant relation of obesity and the chronic plantar heel pain. In the tables, the authors did not published the graph plots of any method, could not comment in relation to the graph. The result supports the statement that has been mentioned in the text part result section. Multivariate analysis shows a low percentage of the accuracy, as other etiological factors for chronic heel pain could have included and result will be accurate.
DISCUSSION ON CONCLUSION;
Authors conclude that obesity and pronated foot may be a risk factor for chronic heel pain and there are associated with each other. Decrease in ankle dorsiflexion range of motion, decrease calf endurance and occupational stress are not associated with the chronic heel pain. Literature supports that ankle joint is the weight bearing joint in the lower limb, increase in body mass index will increase the compressive force on the soft tissue as well the calcaneum (Speare et al, 2005) .continuous stress on the ankle will damage the soft tissue and results in microtear.commonly plantar fascia is stressed more in weight bearing and increase in bobymass index leads to inflammatory changes takes place to produce heel pain. A study by the author in the previous year to examine the association of body mass index with chronic heel pain in non athletic group proves the association of obesity as a risk factor for chronic heel pain (Hills et al, 2001).
Authors justify the association of pronated foot with chronic heel pain as the pronated foot will stretch the plantar fascia and abnormal biomechanics on the foot, weight is shifted to the medial side of the foot. Soft tissue on the medial aspect are stressed and damaged, results in pain by inflammatory response. It was stated that the posture of the foot undergoes changes slowly and once in every 10years.It reveals the participants in case group, foot posture was not changed from the onset of the heel pain .All this factors justifies pronated foot was therefore considered to be a risk factor of chronic heel pain(Kwong et al,1988).
There is no significant difference between the case and control group in co-morbidities as well the occupational rating scale .It states occupational stress and co morbidities cannot be associated with the chronic heel pain. One factor from the occupational stress shows association with the chronic plantar heel pain that is reduced in weight carrying and author justified pain in the heel restricted the participants to carry more weight. Occupational rating scale as questions to be answered for the current work, but pain has reduced the activity of the individual. The participant answered for the past working activity it is a limitation factor and it could not be a risk factor of the chronic heel pain. Calf endurance shows very low score and found not associated with the chronic plantar heel pain.
By the statistical analysis it was found an association exist between the increased ankle dorsiflexion range of motion and its association with chronic plantar heel pain. It is contrary to the author hypotheses .Author explains that previous study shows foot in equinus produce decreased dorsiflexion range of motion and to compensate the foot is pronated. Author justifies that pronated foot will increase the dorsiflexion.Thereis no linear relation found between the ankle dorsiflexion and the chronic heel pain. This correlates the foot posture and the dorsiflexion range of motion, but in the chi-square test it shows the independence of the two variables. Previous study as found the association between the ankle dorsiflexion and strain on the plantar fascia, author determines research requires finding association of the increase in translation of the tibia straining the plantar fascia.
Randomised case control study cannot be taken as a causation, authors explains that accuracy in the case analyse was low as more variables could be included. Authors suggest further research to determine the other hypothesed causative factors for case accuracy. Author had no competing interest.
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