Effects of prefabricated and custom foot orthoses on the biomechanics of the lower limbs of individuals with a posterior tibialis tendon dysfunction during stair climbing.

BACKGROUND: Posterior tibialis tendon dysfunction is a chronic musculoskeletal disorder characterized by a progressive flatfoot deformity which negatively impacts health-related quality of life. Custom foot orthoses modify walking biomechanics in individuals with posterior tibialis tendon dysfunction, but no studies have investigated their effects on stair climbing biomechanics in this population. This cross-sectional study aimed to compare the effects of prefabricated foot orthoses and two models of custom foot orthoses on the biomechanics of individuals with posterior tibialis tendon dysfunction during stair climbing.

METHODS: Fourteen individuals with painful posterior tibialis tendon dysfunction were recruited to undertake a stair climbing task under four experimental conditions: shoes alone, prefabricated foot orthoses, neutral custom foot orthoses and custom varus foot orthoses with a 5° medial wedge and a 4 mm medial heel skive. Hip, knee, ankle and foot angles and moments were compared between conditions, using one-dimensional statistical non-parametric mapping.

FINDINGS: Forefoot dorsiflexion was decreased for neutral custom foot orthoses compared to shoes (P < 0.001). Both custom foot orthoses decreased hindfoot eversion compared to shoes (P < 0.001). Greater ankle eversion moments were observed for both custom foot orthoses compared to shoes (P < 0.001) and prefabricated foot orthoses (neutral custom: P < 0.001).

INTERPRETATION: Neutral custom and custom varus foot orthoses seem appropriate to attenuate biomechanical deficits in individuals with posterior tibialis tendon dysfunction. Longer-term effects of foot orthoses on lower limb biomechanics and clinical meaningfulness of these changes remain to be determined.