Factors associated with foot pain severity and foot-related disability in individuals with first metatarsophalangeal joint OA.

OBJECTIVE To determine whether participant characteristics and localized structural factors are associated with foot pain and foot-related disability in patients with symptomatic first MTP joint OA. METHODS One hundred and fifty-one participants (56 women and 95 men) aged 22-81 [mean age 54.5 (11.2)] years with symptomatic first MTP joint OA underwent a standardized clinical interview and assessment. Participant characteristics [age, gender, height, weight, BMI, duration of symptoms and total years of formal education (education attainment)] and localized factors (first MTP joint dorsiflexion range of motion, severity of radiographic OA, foot posture and plantarflexion strength of the hallux) were determined as potentially associated variables. Outcome variables were foot pain and foot-related disability, determined using the Foot Health Status Questionnaire. Univariate analyses were performed between potentially associated variables and outcome variables. Variables with significant univariate associations were then entered into multivariate linear regression models to identify independently associated variables. RESULTS Education attainment and BMI were both significantly and independently associated with foot pain severity and foot-related disability. However, these variables only explained ∼10-12% of the variance in foot pain and foot-related disability. CONCLUSIONS People with symptomatic first MTP joint OA that have an increased BMI and/or lower level of education attainment experience more foot pain and have greater foot-related disability. Prospective studies are required to confirm these findings and identify other factors associated with foot pain and foot-related disability in people with symptomatic first MTP joint OA.