by Buck Willis, PhD1 , Angel Lopez, DPM2 , Andres Perez, MD-DPM3 , Larry Sheridan, DPM4 ,Stanley R Kalish, DPM5
The Foot and Ankle Online Journal 2 (5): 3
Background: Plantar fasciitis (PF) is a common and debilitating pathology whose chief complaint is acute plantar heel pain. This pathology affects between 1 and 2 million Americans each year, but a specific descriptive pain/disability scale has not been available to measure the severity and/or changes in pain specific to this pathology. The purpose of this study was to examine the PF, Pain and Disability Scale (PFPS) and its ability to discriminate between pain from PF and other heel pain.
Methods: The PFPS survey includes a series of key questions that relate to symptoms and control questions for PF. It also includes visual analogue scale and questions to measure the effect the pain has on activities of daily living. This questionnaire was administered to 400 patients who had been diagnosed with either PF or another pathology causing heel pain (e.g. calcaneal bursitis). Patients’ mean age was 50 years ±16 (242 females and 158 males).
Results: There was a significant difference in scores from PF patients versus other heel pain patients when compared in a one-way analysis of variance (P 0.05) or ethnicity (P > 0.05).
Discussion: The survey was effective in measuring pain that is unique to PF through questions of mobility/function and activities of daily living, and it showed a significant difference between patients with other heel pain vs. PF. This could become an effective tool in diagnosis and assessment of pain unique to PF.
Key words: Plantar fasciitis, Pain and disability scale, heel pain
This is an Open Access article distributed under the terms of the Creative Commons Attribution License. It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot and Ankle Online Journal (www.faoj.org)
Accepted: April, 2009
Published: May, 2009
Plantar fasciitis (PF) is considered to be one of the most common foot pathologies affecting 1 to 2 million Americans each year. [7,9-11] However, a descriptive pain/disability scale has not been available to measure severity and/or changes in pain specific to this pathology.
Current orthopaedic pain scales include a simple 10 point Visual Analogue Scale (VAS) [7,18] to the “Disabilities of Arm/Shoulder/Hand” and the “Levine-Katz Functional Survey,” which measure the effect and disabilities of upper extremity pain has during Activities of Daily Living (ADL).
An overall foot-health questionnaire has been developed,  but this survey measures the broad health status of one’s foot and would not show specific changes in pain from PF in accordance to ADLs. The VAS scores pain on a scale of 1 to 10 or 1 to 100 and has been effective in helping clinician’s measure pain. However, confounding variables affect these scores.
Differences in VAS scores between different dates may not be true barometer of the change in pain. The foot health status questionnaire [7,8] and the VAS [2,7,8,13,17,18] have been used in many studies, but other authors have searched for a better method to measure changes following treatment of PF. Rose, et al., examined this question using nerve conduction (medial calcaneal nerve and the posterior nerve) to gain further insight into patient’s true recovery from PF. 
The foot function index (FFI) [2,8] was compared in clinical settings with PF patients by Landorf and Radford.  Patients were recruited for two trials to examine the “minimal important difference” for the patients when comparing these pain scales. The results indicated the difference that would benefit clinician’s interpretation, but Landorf and Radford remarked that these pain scores themselves do not “Take into account the affect a disorder has on the patient’s life in general.” 
Effective Orthopaedic Rehab: Seven Steps to Complete Recovery was written as a supplemental book for athletic training students and measures pain in ADLs and the effect motion and movement may have on the pain. Reviewers of this scale felt that it was a more complete, analytical measurement of pain than would be acquired by a VAS. 
The validity and source of the questions used in this PF, Pain and Disability Scale (PFPS) survey came from examination and comparison to questions in other text books, recent manuscripts, and from the clinical practice of diagnosing and treating PF. [1,3,8,11,17-19] The PFPS has been compared and validated beside the foot function index, and the 100 point VAS is actually included in the PFPS. However, the PFPS gives a more detailed, analytical analysis of patients’ pain by also examining symptomatic questions used in the differential diagnosis and questions regarding pain in ADLs. The purpose of this study was to examine the PFPS survey’s ability to discriminate between pain from PF and other heel pain.
Four hundred patients who presented with acute heel pain were recruited at four different foot/ankle clinics. Each patient was clinically examined to diagnose and categorize PF versus another heel pain condition such as calcaneal bursitis or calcaneal fractures. (See differential diagnosis on Table 1 and demographics of the patients can be seen in Table 2.) All patients completed the PFPS and informed consent was obtained for each patient participating in this study. Ethical approval for this study was granted by the Copernicus Group IRB.
Table 1 Differential diagnosis in PF.
Table 2 Patient demographics.
The PFPS includes unique symptomatic questions in differentiating PF and control questions as well, which make scores of 0 or 100 points to be invalid. If a patient had recorded either of these scores the test would have been deleted from this study, but no such incidence occurred. The PFPS questions were internally validated with inclusion of the 100 point VAS and externally validated through orthopaedic text and podiatric publications. [1,6,8,16,18,19]
After PFPS questionnaires were collected from patients at four foot/ankle clinics (This form is blinded to the patent’s name and only the Date of Birth was used for tracking as required under the Declaration of Helsinki). A one-way analysis of variance (ANOVA) with post-hoc t-tests were used to determine differences between gender or ethnicity. All statistical tests were performed at an alpha level of 0.05 using SPSS and Microsoft Excel software.
There was a statistically significant difference in scores of PF patients vs. scores of other heel pain patients (P 0.05) or ethnicities (P > 0.05).
Table 3 Results (SD = standard deviation)
The mean difference between PF vs. other heel pain was more than 35 points and this is believed attributed to the fact that the PFPS includes questions uniquely symptomatic to PF like pain from the first steps in the morning and reduced morning pain from toe walking. (See Figure 1, questionnaire.) The purpose of this study was to examine the PFPS survey’s ability to discriminate between pain from plantar fasciitis (PF) and other heel pain.
Figure 1 Study Questionnaire: PFPS Plantar Fasciitis Pain/Disability Scale (PDF)
Current studies support the need for a pain scale that can uniquely assess pain exclusive to PF for diagnosis and assessment. [2,6,8,11,15,18] Landorf and Radford question the statistical significance in changes with the VAS because of the multiple confounding variables associated with that test. They determined that a “Minimally Important Difference” was based not on statistical values alone but changes in “the effect a disorder has on the patient’s life in general”. 
Bennett, et al., developed a questionnaire to measure overall foot health.  Their questionnaire examined four different domains of questions (with 107 participants). The “domains” (or categories) of questions were Pain, Function, Footwear, and General Foot Health. One functional question was “How much does your foot health limit you in walking”  which is ideal in measuring the overall foot health but is not symptom specific to PF.
Rose, et al.,  suggest using nerve conduction to evaluate changes in PF but few podiatrists may have nerve conduction equipment in their office. The PFPS can be administered in almost any setting. The existing pain scales are effective in gauging overall pain, [1,2,8,13,17,18] but they lack the specific inclusion of symptomatic questions that will allow specific, objective, analytical measurement of change in symptoms unique to PF. The PFPS effectively showed the difference between PF patients vs. patients with other pathologies causing heel pain.
The PFPS will allow clinician’s more descriptive, exclusive analysis of PF pain for evaluation of treatment than the 100-pint VAS scale.
For example a young woman’s score VAS and PFPS drops from 70 to 60 which would be “statistically significant” but, it may not show “Minimally Important Difference”.8 However a comparison the current vs. previous PFPS tests of this patient, shows a changed Q#14 because she no longer prefers toe walking, and Q#15 which shows reduced pain from “Walking in the morning” and reduced pain from “Standing after watching a movie.” This would display a “Minimally Important Difference”8 and answer the need for a pain scale that can uniquely assess pain exclusive to PF for diagnosis and evaluation.2,6,8,11,15,18
In this study the PFPS has effectively discriminated pain unique to PF patients vs. heel pain caused by other foot pathologies. A future study should be conducted using this PFPS to measure changes in PF patients’ pain through a treatment regime, lasting several months. That would further validate the efficacy of this questionnaire in diagnosis and assessing pain unique to PF.
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Address correspondence to: Texas State University, Health Physical Education and Recreation, San Marcos, TX (at the time of this study)
1 Dynasplint Systems, Inc. PO Box 92135 Austin, TX 78709. (512) 297-1833
2 Lopez Podiatry; Ft Worth, Texas 910 W North Side Dr Ft Worth, TX 76164. (817) 625-1103 .Dralldpm@aol.com
3 Orlando Foot and Ankle Clinic; Orlando, FL 3670 Maguire Boulevard, Suite 220 Orlando, FL 32803. (407) 423-1234 AnPerez63@hotmail.com
4 Kaiser Permanente, Musculoskeletal Services; Sacramento, CA 2025 Morse Avenue Sacramento, CA 95825. (916) 973-5899 firstname.lastname@example.org
5 Atlanta Foot and Leg Clinic; Jonesboro, GA 6911 Tara Boulevard, Suite #104 Jonesboro, GA 30236 (770) 477-9535 Srkalish@bellsouth.net
© The Foot and Ankle Online Journal, 2009