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Study Design: Experimental laboratory study.

Objectives: To investigate the effect of inflation of the air bladder component of the AirLift PTTD brace on relative foot kinematics in subjects with stage II posterior tibial tendon dysfunction (PTTD).

Background: Orthotic devices are commonly recommended in the conservative management of stage II PTTD to improve foot kinematics.

Methods and Measures: Ten female subjects with stage II PTTD walked in the laboratory wearing the AirLift PTTD brace during 3 testing conditions (air bladder inflation to 0, 4, and 7 PSI [SI equivalent: 0, 27 579, and 48 263 Pa]). Kinematics were recorded from the tibia, calcaneus (hindfoot), and first metatarsal (forefoot), using an Optotrak motion analysis system. Comparisons were made between air bladder inflation and the 0-PSI condition for each of the dependent kinematic variables (hindfoot eversion, forefoot abduction, and forefoot dorsiflexion).

Results: Greater hindfoot inversion was observed with air bladder inflation during the second rocker (mean, 1.7°; range, -0.7° to 6.1°). Less consistent changes in forefoot plantar flexion and forefoot adduction occurred with air bladder inflation. The greatest change toward forefoot plantar flexion was observed during the third rocker (mean, 1.4°; range, -3.8° to 3.9°). The greatest change towards adduction was observed during the third rocker (mean, 2.3°; range, -3.4° to 6.5°).

Conclusions: On average, the air bladder component of the AirLift PTTD brace was successful in reducing the amount of hindfoot eversion observed in subjects with stage II PTTD; however, the effect on forefoot motion was more variable. Some subjects tested had marked improvement in foot kinematics, while 2 subjects demonstrated negative results. Specific foot characteristics are hypothesized to explain these varied results.