Online questionnaire, clinical and biomechanical measurements for outcome prediction of plantar heel pain: feasibility for a cohort study

Abstract Background Plantar heel pain (PHP) accounts for 11-15% of foot symptoms requiring professional care in adults. Recovery is variable, with no robust prognostic guides for sufferers or clinicians. Therefore, we aimed to determine the validity, reliability and feasibility of questionnaire, clinical and biomechanical measures selected to generate a prognostic model in a subsequent cohort study. Methods Thirty-six people (19 females & 17 males; 20-63 years) were recruited with equal numbers in each of three groups: people with PHP (PwPHP), other foot pain and healthy controls. Eighteen people performed a questionnaire battery twice in a randomised order to determine online and face to face agreement. The remaining 18 completed the questionnaire battery once, plus clinical and biomechanical measurements. A progressive loading challenge was developed and assessed. Results There were no systematic differences between online and face to face administration of questionnaires ( p-values all >.05 ) nor an administration order effect (d =-0.31-0.25). Questionnaire reliability was good or excellent (ICC 2,1_absolute ) (ICC 0.86-0.99), except for two subscales. Full completion of the survey was only 77%, taking 29±14 minutes. Clinically, PwPHP had significantly less ankle dorsiflexion and hip internal rotation compared to healthy controls [mean (±SD) for PHP-OP-H = 14°(±6)-18°(±8)-28°(±10); 43°(±4)- 45°(±9)-57°(±12) respectively; p<.02 for both]. Plantar fascia thickness was significantly higher in PwPHP (3.6(0.4) mm vs 2.9(0.4) mm, p=.01 ) than the other groups. The graded loading challenge led to progressively increasing kinetic foot load. Conclusion Online questionnaire administration was valid therefore facilitating large cohort recruitment and being relevant to remote service evaluation and research. The graded loaded challenge increases load progressively and warrants future research. The physical and ultrasound examination revealed expected differences between groups. Clinician and researchers can be confident with these methodological approaches and the cohort study is feasible.