Patellar tendon bearing brace: Combined effect of heel clearance and ankle status on foot plantar pressure

Abstract

Background: Heel clearance and ankle status (free or locked) are of major determinants affecting peak plantar pressures and contact area in patellar tendon bearing brace and have been separately studied by many researchers. This study investigated the combined effect of ankle status and heel clearance on contact area and peak plantar pressure in different areas of foot (hindfoot, midfoot, and forefoot). Study design: Before-after repeated measurement trial. Methods: Nine healthy male volunteers walked 8 m with normal shoe and four conditions of patellar tendon bearing brace wear. Repeated-measure analysis of variance test was used to compare contact area and plantar pressure changes in three areas of the foot. Results: Application of patellar tendon bearing brace significantly reduced overall plantar pressure and contact area (p < 0.01). Although both contact area and plantar pressure significantly decreased in hindfoot and midfoot, plantar pressure increased in forefoot area (p < 0.05). Conclusions: Application of the patellar tendon bearing brace can reduce the overall peak plantar pressure in the foot but increases focal plantar pressure in forefoot. Excessive lifting of the heel seems to minimize the contact area, thus increase focal pressure in forefoot. Overall, plantar pressure seems to be more effectively off-loaded by combining maximum heel clearance and restriction of the ankle joint. Clinical relevance Although effective parameters of patellar tendon bearing brace have been separately addressed in previous studies, no study was found that investigated the combined effect of ankle status and heel clearance. This study investigates the combined effect of these parameters and provides detailed information on clinical application of the patellar tendon bearing brace.