Development and validation of a Greek language version of the Manchester Foot Pain and Disability Index

BACKGROUND The Manchester Foot Pain and Disability Index (MFPDI) is a 19 item questionnaire used to assess the severity and impact of foot pain. The aim of this study was to develop a Greek-language version of the MFPDI and to assess the instrument's psychometric properties. METHODS The MFPDI was translated into Greek by three bilingual content experts and two bilingual language experts, and then back-translated into English to assess for equivalence. The final Greek version was administered, along with a questionnaire consisting medical history and the Medical Outcomes Study Short Form 36 (SF-36), to 104 Greek-speaking, community-dwelling people (64 female, 40 male), aged between 64 and 90 years (mean 73.00, SD 5.26) with disabling foot pain. RESULTS The Greek translation of the MFPDI was found to have high internal consistency (Cronbach's alpha= 0.89, and item-total correlation coefficients from 0.33 to 0.72). Principal components analysis revealed a four-factor structure representing the constructs of functional limitation, pain intensity, concern with appearance and activity restriction, which explained 60.8% of the variance, with 38.9% of the variance explained by the first construct (functional limitation). Six items demonstrated different factor loadings to the original English version. CONCLUSION The Greek-language version of the MFPDI appears to be a valid tool in assessing foot pain in Greek-speaking older people. The total MFPDI scores are comparable between the Greek and English version, however due to differences in the factor loadings of some items, between-language comparisons of MFPDI should be undertaken with some caution.