The Manchester Foot Pain and Disability Index (MFPDI)
Background
The Manchester Foot Pain and Disability Index (MFPDI) is a Patient Reported Outcome (PRO) measure developed and validated to measure pain specifically related to a foot disability. The MFPDI is a suitable instrument for assessing the impact of painful foot conditions in community and clinical populations.
The MFPDI was the first foot related pain measure to incorporate the views of people with known foot problems from the early stages of development. This self-administered PRO has been validated for use among patients of varying levels of disability associated with a specific foot or general medical condition.
The MFPDI was designed and developed by researchers at the University of Manchester and is available on license through Isis Outcomes.
Back to top
Attributes of the MFPDI include
Valid
The MFPDI has been repeatedly shown to demonstrate content, construct and criterion validity amongst people with varying levels of foot problems.
Reliable
The MFPDI exhibits good internal consistency.
Sensitive
The MFPDI has demonstrated its ability to discriminate between known groups with varying levels of a foot specific disability within both clinical and population settings.
Ease of use
The MFPDI is quick and easy to complete, administer and score.
The PRO
The MFPDI is a self-administered, paper based PRO consisting of 19-items assessing foot pain and disability. The PRO contains three constructs (four subscales) which reflect disabilities associated with foot pain and two additional items relating to work and leisure. The three constructs identified within the MFPDI are:
- Functional limitation (10 items)
- Pain intensity (7 items)
- Personal appearance (2 items)
Responses are recorded on a three point scale:
- None of the time
- On some days
- On most /every day(s)
Scoring system
Individual scores for each construct can be generated to produce an overall index of foot disability.
Validated Therapeutic Areas
The MFPDI can be used to assess the impact of painful foot conditions in community and clinical populations.
Development
The MFPDI was developed using a mixed method design incorporating a number of stages consistent with best practice:
Phase 1: Incorporating the patient’s perspective in order to understand the domain under investigation (Content validity)
Item generation
Interviews were conducted with 32 patients attending foot clinics for treatment to explore aspects of pain, disability, activity limitation and footwear. Statements were generated relating to foot problems and refined to form 19 items.
Pre-testing
Eleven patients attending podiatry clinics were asked to complete the first draft of the 19 item questionnaire. Changes to the questionnaire included; ensuring participants focused on disability relating to foot pain and not pain relating to general health, adding a response option in case an item was not personally relevant to the patient and adding a mechanism to reduce missing data.
Phase 2: Questionnaire pilot
The questionnaire was piloted to confirm acceptability among 100 general practice patients. Patients appeared to accurately complete and understand the questionnaire (particularly amongst the older age group).
Phase 3: Establishing validity and reliability
Factor analysis confirmed the presence of three domains within the MFPDI - (functional limitation, pain intensity and personal appearance). More recent research has shown two of the three constructs (functional limitation and pain) conform to Rasch measurement principles indicating the presence of unidimensional, equal interval scales.
Construct validity
The MFPDI was tested to ensure its ability to discriminate between groups expected to have different levels of foot disability. Three participant groups were included during this phase:
- Patients (45) attending rheumatology clinic, but not specifically for foot problem
- Patients (33) attending their general practitioner with foot complaint
- Patients (1000) on a GP register asked to take part in a general population survey if they had experienced pain in their foot for a whole day in last month.
Patients reporting pain or having marked at least one item positively were invited to take part in a standardised interview and examination. Test scores found greatest pain/disability among rheumatology patients and least pain/disability among community subjects.
Criterion validity
To test the MFPDIs ability to correlate with an established disability instrument, patients were asked to complete a sub scale of the Functional Limitation Profile questionnaire. Responses confirmed agreement between MFPDI scores and similar items on the Functional Limitation Profile.
Reliability
Internal consistency was confirmed using Cronbachs alpha (0.99) and Item total correlation values between 0.25 and 0.62.
Key references
Garrow AP, Papageorgiou AC, Silman AJ, Thomas E, Jayson MI, Macfarlane GJ. Development and validation of a questionnaire to assess disabling foot pain. Pain. 2000 Mar;85(1-2):107-13
Muller S, Roddy E. A rasch analysis of the Manchester foot pain and disability index. J Foot Ankle Res. 2009 Oct 30;2:29.
Roddy E, Muller S, Thomas E. Defining disabling foot pain in older adults: further examination of the Manchester Foot Pain and Disability Index. Rheumatology (Oxford). 2009 Aug;48(8):992-6. Epub 2009 Jun 18.
Example studies
The MFPDI has been used to assess outcomes in a range of studies of pain related to foot disability. The MFPDI has been employed in clinical trials, cohort studies, and quality of life studies in a range of clinical and community settings. Examples of the use of the MFPDI include:
van der Zwaard BC, Elders PJ, Knol DL, Gorter KJ, Peeraer L, van der Windt DA, van der Horst HE. Treatment of forefoot problems in older people: study protocol for a randomised clinical trial comparing podiatric treatment to standardised shoe advice. J Foot Ankle Res. 2011 Mar 31;4(1):11.
Roddy E, Muller S, Thomas E. Onset and persistence of disabling foot pain in community-dwelling older adults over a 3-year period: a prospective cohort study. J Gerontol A Biol Sci Med Sci. 2011 Apr;66(4):474-80. Epub 2010 Nov 24.
Menz HB, Roddy E, Thomas E, Croft PR. Impact of hallux valgus severity on general and foot-specific health-related quality of life. Arthritis Care Res (Hoboken). 2010 Nov 15.
Mickle KJ, Munro BJ, Lord SR, Menz HB, Steele JR. Foot pain, plantar pressures, and falls in older people: a prospective study. J Am Geriatr Soc. 2010 Oct;58(10):1936-40.
Menz HB, Tiedemann A, Kwan MM, Plumb K, Lord SR. Foot pain in community-dwelling older people: an evaluation of the Manchester Foot Pain and Disability Index. Rheumatology (Oxford). 2006 Jul;45(7):863-7. Epub 2006 Jan 31.
Bowen CJ, Edwards CJ, Hooper L, Dewbury K, Sampson M, Sawyer S, Burridge J, Arden NK. Improvement in symptoms and signs in the forefoot of patients with rheumatoid arthritis treated with anti-TNF therapy. J Foot Ankle Res. 2010 Jun 17;3:10.
Used as a template for further measures
The MFPDI has been used as template in the development of other foot related PROs which are also available from Isis Outcomes, namely the MOxFQ.
Available Languages
Click here to see available languages:
Kaoulla P, Frescos N, Menz HB. Development and validation of a Greek language version of the Manchester Foot Pain and Disability Index. Health Qual Life Outcomes. 2008 Jun 1;6:39.
Collaboration
The Manchester Foot Pain Disability Index is available from Isis Outcomes following collaboration with University of Manchester Intellectual Property.
Request a Licence
A license to use the MFPDI PRO can be obtained by completing the online licence request form.
If you would like further information about this PRO please contact one of the Isis Outcomes team.