Can short-term effectiveness of anti-pronation taping predict the long-term outcomes of customized foot orthoses: Developing predictors to identify characteristics of patients with plantar heel pain likely to benefit from customized foot orthoses

Abstract

Background: Foot orthoses are widely used to manage plantar heel pain (PHP). However, the evidence concerning the effect of foot orthoses on PHP is not conclusive. The study aims to identify the characteristics of patients with PHP likely to achieve a positive outcome after customized foot orthoses and to verify the concept that patients who respond positively to anti-pronation taping would achieve a positive prognosis after wearing foot orthoses for six months. Methods: This is a prospective observational cohort study. Seventy-four patients with PHP underwent a baseline examination and received anti-pronation taping to their painful feet. The taping effects on pain and function were assessed at the 7-day follow-up visit. Then, all patients received an intervention for their PHP with customized foot orthoses for six months. Outcome was assessed with a numeric pain rating scale, the patient-specific functional scale, the foot function index, and the global rating of perceived change. Significant reduction of pain, increase of function, and perception of a meaningful improvement were considered a positive response. Results: Of 74 patients, 49 had a positive response to the customized foot orthosis treatment. Five predictors were identified: (1) the average pain intensity decreased by over 1.5 points with taping, (2) the range of ankle plantarflexion > 54 degrees, (3) the strength of ankle plantarflexors on the symptomatic side was equal to or stronger than that on the other side, (4) the range of hip internal rotation < 39 degrees, and (5) the range of hip external rotation > 45 degrees. The presence of three or more predictors increased the rate of achieving positive outcome from 66 to 89%. Conclusions: The predictors of customized foot orthosis outcome in patients with PHP are related to several physical measures of a lower extremity. Findings of the study can be used to screen and select patients with PHP for foot orthosis intervention. Moreover, patients who respond positively to anti-pronation taping would also benefit from the customized foot orthoses. However, since there was no control group in the current study, it is inappropriate to draw conclusions about the effectiveness of the foot orthoses treatment. Trial registration: The trial was retrospectively registered with the Australian and New Zealand Clinical Trials Registry (ACTRN 12617000119392).