As concern exists as to how much load a child should carry, we studied the gait effects of increased added mass with varied backpack styles. Backpack loads of up to 25% increase above body weight were added to three backpack styles (double-strap, single-strap, hipster). Individuals ambulating thirty-meters, were instrumented with the WPGM tm (Walkabout Portable Gait Monitoring System). Relative power of the approximate center of mass in three dimension, gait frequency and forward and vertical asymmetries were measured. Five females (avg. age 12.4 years) and five males (avg. age 12.8 years) were compared to a group of forty-eight normal age-matched controls. Data was analyzed with the GaitView tm (Innomed) and Excel tm (Microsoft) programs. Overall, with 25% increased mass above body weight there was an 8% reduction in velocity (r2 0.9641). Velocity reduction occured with decreased step length (r2 0.9924). The hipster showed significant slowing with no difference between one and two strap models. Forward asymmetry increased 20% and vertical asymmetry increased 10% for all backpack styles. The two-strap gave minimal asymmetry with the one strap and hipster showing significant differences. Relative power decreased 20% and 15% in the vertical and forward dimension and increased 15% horizontally. Significant difference of approximate center of mass measurements for boys and girls with increasing backpack weight occurred between 10–15% increased loads. With loads of up to 25% greater than body weight, differences are seen with gait velocity slowing, increasing asymmetry, and greater horizontal power. The two-strap backpack is superior in its effect of minimizing asymmetry and velocity impacts.
The purpose of this study is to assess the clinical outcome and gait analysis of a new technique for ankle arthrodesis using a Fibular Sparing Z Osteotomy (FSZO). The FSZO technique for ankle arthrodesis utilises a lateral approach where the fibula is osteotomised and reflected posteriorly on a soft tissue hinge to allow easy access to the ankle joint for an anatomic arthrodesis. Outcome assessment at six months follow up included health related quality of life (SF36) and joint specific (American Orthopedic Foot and Ankle Society Ankle-Hindfoot, Ankle Osteoarthritis Scale, Foot Function Index) clinical outcome scores. Gait Analysis was completed using the Walkabout Portable Gait Monitor® which includes a wireless gait belt housing a triaxial arrangement of accelerometers, resting behind the lumbar vertebrae, approximately at position of centre of mass to quatintfy surgery, lurch and functional limb length difference (LLD). There was a significant improvement in the health related quality of life and the joint specific clinical outcome scores at six months follow up. The six month gait study preliminary analysis showed improvement in some parameters of gait but worsening in others. The FSZO ankle arthrodesis technique provides improvement in clinical outcome scores and certain gait parameters at early follow up.
