Kinematic Compensations as Children Reciprocally Ascend and Descend Stairs with Unilateral and Bilateral Solid AFOs. George E. Gorton, BS, Maureen T. Nahorniak, PT, MBA, Mary E. Gannotti, Ph.D., and Peter D. Masso, M.D. Shriners Hospitals for Children, Springfield, Massachusetts, 01104 USA Introduction Mobility of the ankle joint is critical to the smooth control of forward progression during level walking (4). The muscles surrounding the ankle provide power for both advancement and restraint of forward motion of the body. McFayden et al. (3) have shown that during stair ascent the ankle helps control the position of the center of gravity by lifting and translating the body forward and that during descent the ankle functions to absorb the initial impact shock and to provide a pivot for descent controlled by the knee. Andriacchi et al. (1) and Livingston et al. (2) have described the kinematics, including the normal sagittal range of the unrestricted ankle in stair climbing for adults. In pediatric orthopaedics, solid ankle foot orthoses (AFOs) are routinely prescribed to control joint position, to protect anatomic structures, and to augment function. Loss of ankle mobility will have a profound impact on the dynamics of both level walking and stair climbing. There is no evidence in the literature of how the use of an ankle foot orthosis impacts stair climbing or what kinematic compensations are necessary for loss of sagittal plane ankle motion. The purpose of this study was to evaluate changes in the kinematic patterns as children with normal motor control ascended and descended stairs with unilateral and bilateral solid AFOs. This will contribute to the understanding of the role of the ankle joint in performing the functional task of stair climbing and how the body compensates for loss of ankle motion. Methodology Ten healthy children (four male, six female) with no previous history of motor control or orthopedic problems participated in this study. The subjects had an average age of 9.8 years (range, 8.1 to 12.8 years), height of 139 cm (range, 129 to 159.5 cm), weight of 36.0 kg (range, 25.4 to 53.9 cm) and leg length of 72.3 cm (range, 65.0 to 84.0 cm). Each subject reciprocally ascended and descended five steps with a slope of 32 degrees (15.2 cm rise, 24.1 cm run, 91.0 cm width) without the use of a railing. Subjects performed three ascents and three descents under each of three separate conditions (shoes alone, right AFO, bilateral AFOs) at a self selected velocity and cadence. Kinematic data were collected with a six camera Vicon VX system, AMASS data reduction software and Vicon Clinical Manager modeling software. A multi-way within subjects measures ANOVA (repeated measures) was used to assess differences in selected kinematic parameters. Results Compensations seen with the use of either unilateral or bilateral AFOs to ascend or descend stairs are shown in Table 1. The magnitude of these compensations increased with use of bilateral AFOs compared to a right AFO.