| 摘要: | Developmental dysplasia of the hip (DDH) is characterized by an abnormal relationship of poorly formed acetabulum and displaced femoral head [2]. Osteotomy is a common way to treat the children with DDH, as a high success rates treatment. After the treatment, correction of the acetabulum and femoral head with a consequent reduction of avascular necrosis (AVN) [3]. AVN remains one of the most severe complications to the treatment of for DDH [4]. Further, the affection of biomechanical factors associated with AVN development are still unclear. Walking are the daily function activities which requires enough body balance control. For this reason, walking may have potential to provide the biomechanical insights different between patients with or without AVN. This study aimed to investigate the differences in control of the locomotor of the body control between DDH children with or without AVN during walking.
Seven DDH children with AVN, seven DDH children and fifteen age-match healthy children in the study with informed written parental consent. Each subject will walk at a self-selected pace and cross a height-adjustable obstacle at 10-30% of his/her leg length. Forty-one reflective markers were placed on the bony landmark of each lower limb segment. Marker trajectories were measured with VICON motion capture system. End-point variables together with the three-dimensional joints kinematics of lower limb will be obtained. The key gait events, namely toe-off (TO), heel-strike (HS), contralateral leg toe-off (CTO) and contralateral leg heel-strike (CHS), and the phases in gait cycle, namely initial double limb support (DLSi), single limb support (SLS), terminal double limb support (DLSt), swing (SW) were extracted. Comparisons of the inclination angle (IA) and the rate of change of inclination angle (RCIA) among groups was tested using Kruskal-Wallis H test (α=0.05).
Among the affected side in three groups, at the sagittal plane, compared to the control, the non-AVN had decreased RCIA range during DLSt and decreased RCIA average during SW, at the frontal plane, the AVN had decreased IA average during DLSi, and the non-AVN had increased IA range during SW. Among the sound side in three groups, at the sagittal plane, compared to the non-AVN, the AVN and control showed increased RCIA range during DLSi. And compared to the control, the AVN had decreased RCIA at both sagittal and frontal plane during DLSt.
Among three groups, the main effects on IA and RCIA of the AVN group were found in the frontal plane during the body transferred from the affected side to sound side, with the increased loading. The Non-AVN group was found the decreased RCIA range in the sagittal plane of the Non-AVN. However, their balance control may be compromised with the decreased range of RCIA during body transfer from the affected side to the sound side. The current results suggest that the AVN in patients after osteotomy for DDH affected the whole-body balance control in the frontal plane and the patients after osteotomy for DDH without AVN affected the whole-body balance control in the sagittal plane, which can be the future research direction of the affected on balance control in AVN. |
