Objective
Sagittal imbalance in lumbar degenerative kyphosis (LDK) is usually more evident when walking, suggesting its dynamic nature. Radiographic examination which only revealed the static status of the spine was considered to be inadequate for assessment of this condition. Gait analysis allows estimation of dynamic spinal imbalance associated with the pelvis and lower extremities in LDK. This study was designed to predict the success of surgery for LDK with gait analysis.

Method
Twenty-six patients who had corrective surgery after gait analysis and had been followed up for more than two years were included in this study. All patients were female, and in average 57.1 years of age (42∼70). Group I consisted of 21 satisfactory patients with marked improvement in stooping, and Group II consisted of five patients with persistent stooping, whose condition remained unsatisfactory despite surgery. In order to find the cause of postoperative persistent stooping, various radiographic and preoperative gait parameters were compared between the two groups.

Results
The average angle of anterior pelvic tilt, hip, and knee flexion were more increased in Group II than Group I. The pattern of hip internal moment in stance phase of gait cycle was biphasic in Group I, similar to the normal pattern, whereas it was monophasic and internal hip extensor hip moment was increased throughout the stance phase in Group II.

Conclusion
An available tool that permitts practical evaluation of dynamic sagittal imbalance of the spine is gait analysis as substantiated by the results of this study.