THE IMPORTANCE OF INTERACTION AMONG PELVIC, LUMBAR SPINE, AND NECK MOVEMENT IN MAXIMUM HIP FLEXION ANGLE

Introduction Hip-Spine syndrome has various clinical aspects. For example, schoolchild with severe congenital dislocation of the hip have unfavorable standing posture and disadvantageous motions in ADL. Hip-Spine syndrome is closely related closely as the adjacent lumbar vertebrae and the hip joint. Furthermore, not only the pelvis and the lumbar spine, but also the neck position might influence on the maximum hip flexion angle. In this study, we examined the maximum hip flexion angle and pelvic movement angle by observing the lumbar spine, the pelvis and the neck in three different positions. Subjects and Methods The participants were five healthy volunteers (three males and two females) and ranged in age from 16 to 49 years. We measured the hip flexion angle (=∠X) and the pelvic tilt angle (=∠Y), using Zebris WinData and putting the six markers on skin. The positions of the marker are Femur lateral condyle (M1), Greater trochanter (M2), Lateral margin of 10th rib (M3), Anterior superior iliac spine (M4), Superior lateral margin of Iliac (M5), and Acromion (M6). We performed maximum hip flexion three times in three positions and measured ∠X (=∠M1,2,3) and ∠Y (=∠M4,5,6) and calculated the mean and SD of each position. The first position (P1) that we investigated is the regular position specified by the Japanese Orthopedics Association and Rehabilitation Medical Association. The second position (P2) is performed in the limited position of the posterior pelvic tilt and lumbar movement, by placing the tube under the subject's lower back. The third position (P3) is the altered limited position of P2 added by placing the 500ml PET bottle filled water under the back of the subject's neck. Analysis A two way factorial analysis of variance was used for statistical analysis to examine the difference among three different positions (P1, P2 and P3) in ∠X and ∠Y. A significance level was set at P < 0.05. We also calculated Spearman rank correlation coefficients to determine the correlation between ∠X and ∠Y. Results There was a statistically significant difference among three different positions (P1, P2 and P3) in both ∠X and ∠Y (p < 0.01). Slight strong correlations were found between ∠X and ∠Y in three different positions. (r =0.5178571). The smallest values of ∠X and ∠Y were obtained in P1. The values of ∠X and ∠Y in P3 were all smaller than those in P2. Conclusions The limited movement of pelvic and lumbar spine, and neck different positions give the limit to a maximum hip joint flexion angle.