Keywords
risk factors - plantar fasciitis - chronic pain
Introduction
Plantar fasciitis (PF) is the most common cause of chronic plantar heel pain.[1] It is a degenerative syndrome of the plantar fascia resulting from repeated trauma
at its origin on the calcaneus. Flexible foot, tibia vara, ankle equinus, rear foot
varus, forefoot varus, compensated forefoot valgus, and limb length inequality can
cause an abnormal pronatory force. Increased pronation produces additional stress
on the anatomic central band of the plantar fascia and may ultimately lead to plantar
fascitis.[2] Running has also been found to be a risk factor for developing plantar fascitis.[3] Weight gain, occupation-related activity, anatomical variations, poor biomechanics,
overexertion, and inadequate footwear are contributing factors for the same.[4]
Excessive BMI (especially weight as the contributing factor) has a strong association
with PF in the non-athletic population.[5]
[6] Risk factors can be broadly divided into intrinsic and extrinsic factors. Intrinsic
factors can be further subdivided into anatomic and biomechanic, while extrinsic factors
include poor alignment, hard surface, walking barefoot, prolonged weight bearing,
and low-quality footwear. Anatomic factors include obesity, pes planus, pes cavus
and shortened Achilles tendon, and biomechanic factors include over-pronation, limited
dorsal ankle flexion, weak intrinsic muscles, and weak plantar flexor muscles.[5]
[7]
There is no specific scoring system catered to plantar fasciitis for severity of illness
and assessment with treatment. Though other common scores, such as the visual analog
scale (VAS), the Foot and Ankle Ability Measure (FAAM), the Foot and Ankle Disability
Index (FADI), and the American Foot and Ankle Society (AOFAS), have been traditionally
used for objective and subjective assessments of plantar fasciitis, they are either
too generalized for the foot and ankle (FAAM, FADI and AOFAS) or to pain anywhere
else in body (VAS).[8]
[9]
[10]
[11]
In the present study, we have attempted to find out modifiable risk factors that could
be used for assessment of plantar fasciitis and using those risk factors to formulate
a scoring system for quantifying the problem at presentation and in follow-up.
In a study conducted at a tertiary health care facility at LHMC, New Delhi, India,
“To evaluate various causes of Heel Pain and Efficacy of Autologous Platelet Rich
Plasma Injection in Cases of Proximal Plantar Fasciitis Which Have Failed Conservative
Management,” the modifiable risk factors were studied with help of Pearson coefficient
(R).
Since the most frequently reported complaint in plantar fasciitis is chronic heel
pain, an attempt was made to find an association between the VAS and risk factors.
Body mass index, fitting of shoes, cushioning of shoes, and level of activity were
considered as variables that could affect the pain in plantar fasciitis based on the
available literature. Age and sex were considered non-modifiable risk factors along
with all the other anatomic factors requiring surgical correction. On the basis of
significant association, an index was formulated for objective assessment of plantar
fasciitis at presentation and following treatment. All those risk factors that are
modifiable but need surgical intervention for modification were not considered modifiable
due to technical reasons for modifications. Body mass index (values corresponding
to obesity I and II i.e., >24.99 and >29.99, by WHO) an VAS are quantitative variables
and others are qualitative variables;[12]
[13] therefore, a quantification was done based on the available literature for grading
in the scoring system. On the basis of significance of the above mentioned associations
with the symptomatology, a novel index system for quantitative objective assessment
of plantar fasciitis is proposed. The purpose of the objective assessment is to create
an unbiased assessment system for quantification of the disease during its presentation
and treatment process, which cannot be achieved with subjective assessment, that tends
to quantify the “problem” associated with disease rather than the disease and may
have high inter-observer and intraobserver variation.
Results
A total of 50 patients were studied, 23 male and 27 female, with a mean age of 41.94
years and standard deviation (SD) of 8.94. The mean BMI was 28.79 (29.82 for females
and 27.57 for males) kg/m2. The Pearson correlation of various factors with VAS is shown in [Table 1].
Table 1
|
R-value
|
p-value
|
|
BMI
|
0.64
|
< 0.0001
|
|
Well-fitting shoes
|
−0.16
|
0.26
|
|
Well cushioned shoes
|
−0.41
|
0.0033
|
|
Level of activity
|
0.05
|
0.72
|
Body mass index showed a strong positive correlation with VAS, with an R-value of
0.64 and a p-value < 0.0001. For footwear, well-fitting shoes showed a negative correlation, with
an R-value of - 0.16 and a p-value of 0.26, thus showing no significant association. For cushioning of shoes,
well-cushioned shoes showed a strong negative correlation, with an R-value of - 0.41,
showing a significant association with symptoms of patient, with a p-value of 0.0033. Level of activity was divided in 3 tiers: sedentary lifestyle, moderate
activity, and heavy activity, and though there was a weak positive correlation, with
R-value of 0.05, it showed no significant association with symptomatology (p-value = 0.72)
Based upon the significance levels, a novel index system for quantitative assessment
of plantar fasciitis was proposed based on VAS, BMI levels for obesity I and obesity
II, and cushioning of shoes (discussed in detail in the Discussion section).
Discussion
Plantar fasciitis is a cause of chronic heel pain. The chronicity is what makes a
person accommodating to the pain and usual late presentations, but what physicians
often fail to understand is that not only the disease is chronic and so can be the
risk factors—which on one hand may not cause any significant distress to the patient
because of chronicity, while on other can be a significant contributor to the progression
of disease process. We can understand this in terms of the aforementioned risk factors,
such as obesity and ill-cushioned shoes. The shoe a man wears is often a statement
of his comfort rather than his status, and, thus, well-cushioned shoes may look inviting
to be worn but the person tends to get accommodated to his or her footwear with time—which
acts as a slow poison for the plantar fascia and works unremarkably. Similarly, obesity
is often slow to acquire and the patient often gets used to it until it starts causing
severe health problems, which is often not found in young grade I obesity patients.
Thus, it can be understood that though chronicity is itself a statement of plantar
fasciitis, this chronicity is the statement of otherwise neglected risk factors, such
as ill-cushioned shoes (which in many cases can be rather comfortable for the patient
to wear) and obesity —especially in the new onset and early phases—when it is causing
less impacts on health. It should also be understood that this scoring system is for
the non-athletic population, who usually do not suffer wear and tear of plantar fascia.
Now, let us understand each of the individual components of Ranjeet- Kunal Index for
Scoring Plantar fasciitis (RKISP). Based on the above data, it can be understood that
BMI, as indicated by earlier studies, has a strong positive correlation with the symptomatology
and the VAS in plantar fasciitis. Since obesity shows a very significant association,
obesity can be further divided on the basis of the WHO grading of BMI for the Indian
population, with BMI > 24.99 defined as obesity I and > 29.99 as obesity II.[12] This grading is for Asian population and might be different in the western population,
as the grading of obesity is different in their scenario and can be modified based
on the WHO grading of obesity for the western population. Based on the severity of
obesity, grading in the index can be done by assigning 1 point to the former and 2
points to the latter.
The VAS is a scale that has been commonly used for quantifying pain in patients with
different etiologies. A VAS > 7.5 is a measure of severe torment for the patient.[13] A VAS < 4.5 usually defines unremarkable pain and, hence, has not been included
in the index. Severe pain, with VAS > 7.5, has been assigned 2 points in the score.
Since cushioned footwear showed a strong negative correlation to the symptomatology,
it becomes obvious that changing an ill-cushioned shoe will provide a dramatic response
in both prevention and treatment of symptomatology of plantar fasciitis. A change
in footwear, thus, becomes an obvious part of management, and, not only that, it shall
become an important part in the quantifying assessment of the disease.
As shown in [Table 2], three parameters have been considered for objective assessment of plantar fasciitis
in the pre and posttreatment periods. The RKISP includes these three parameters that
add up to a maximum value of 5 and a minimum value of 1 (the minimum criteria for
indexing was considered VAS > 4.5, which is the criteria for remarkable pain by Hawker
et al.[13]). The RKISP can be used for grading plantar fasciitis.
Table 2
|
BMI
|
> 24.99 (obesity I)
|
1
|
|
> 29.99 (obesity II)
|
2
|
|
Worn out cushion
|
|
1
|
|
VAS
|
> 4.5
|
1
|
|
> 7.5
|
2
|
|
Total
|
5
|
Implications of the RKISP
-
Objective assessment at the time of presentation of plantar fasciitis and at consecutive
follow-ups. Objective assessment not only helps in unbiased quantification of disease
but also leads to uniformity of treatment and research protocols.
-
Grading of plantar fasciitis. Grading can be done based on additional parameters which
may worsen the pain in plantar fasciitis patients.
-
Prognosis of conservative management is inversely proportional to index. This can
be understood in a way that a higher index is prone to have more conservative ways
of management that can be used. For example, a patient that presents with an index
of 2 with a VAS of 9/10 but wears a well-cushioned shoe and has a BMI < 24.99 will
have a worse prognosis than a patient with an index of 4 wearing worn out shoes and
classified with obesity II with a VAS of 5 with conservative management.
Conclusion
An objective assessment can be achieved with RKISP, quantifying the disease in terms
of problem and risk factors. This index can be further used for grading and prognosticating
plantar fasciitis at the time of presentation and during treatment, as explained above.
Further research needs to be done on larger samples for validation of RKISP. The authors
also recommend the use of objective assessment systems for plantar fasciitis in addition
to the widely used subjective systems.
Fig. 1 Flowchart of the methodology employed to determine the objective scoring system for
evaluation of plantar fasciitis in non-athletic patients.
