Gait analysis of patients who have Paget disease.

Eighteen patients who had Paget disease were evaluated in our gait-analysis laboratory. The results were compared with those of ten healthy age-matched control subjects in order to quantitate the biomechanical changes and to describe the specific patterns of walking that occur secondary to bowing of a lower extremity. Kinetic and kinematic data were acquired using infrared video cameras and force platforms; electromyographic data were obtained using surface electrodes. Velocity and cadence were decreased and stride time and double-limb support time were increased in the patients who had Paget disease compared with the control subjects. Frequently, the knee of the limb that was affected by Paget disease was flexed during stance and flexed less during swing. When the involved knee was in varus angulation it also had an increased adduction moment, which may be related to the bowing deformity. Although the patterns of ground-reaction force were similar in the patients and the control subjects, the magnitudes of forces were reduced in the patients. Phasic muscle activity was similar in the two groups.