Right hip adduction deficit and adolescent idiopathic scoliosis

Investigation of multidirectional hip range of motion and hip motion asymmetry in individuals with idiopathic scoliosis with different curve patterns

BACKGROUND

While some studies of the asymmetry of lower limbs in individuals with idiopathic scoliosis exist, there is a need for multidirectional studies conducted on hip joint range of motion and its relationship to curve patterns in idiopathic scoliosis.

OBJECTIVES

This study analyzes the hip joint range of multidirectional motions, hip motion asymmetry and investigates them according to curve patterns in individuals with idiopathic scoliosis.

METHODS

The sample included 108 females with idiopathic scoliosis. Participants were divided into three groups: double curves, single thoracic curve and single lumbar curve. The range of hip flexion and extension, abduction and adduction, and internal and external rotations were assessed actively and passively with a universal goniometer. The range of motion, left-right asymmetry and the mid-points of the ranges of motion were analyzed.

RESULTS

The passive range of the right hip abduction was higher in the thoracic curve group vs. the lumbar curve group. Active and passive ranges of hip extension were higher in the left hip vs. right hip. Active left-right asymmetry was higher than passive left-right asymmetry.

CONCLUSION

Individuals with idiopathic scoliosis had different hip abduction motions according to curve pattern that originated from single curves. Left-right hip asymmetry was seen for the hip extension motion. Higher left-right asymmetry for active motion than passive motion in hip abduction may indicate a problem in motion perception in individuals with idiopathic scoliosis.

Analysis of Proximal Femoral Parameters in Adolescent Idiopathic Scoliosis

BACKGROUND

Assessment of the proximal femoral parameters in adolescent idiopathic scoliosis using three-dimensional radiological image reconstructions may allow better characterization than conventional techniques.

METHODS

EOS 3D reconstructions of spines and femurs of 320 scoliotic patients (10-18 years old) and 350 control children lacking spinal abnormality were performed and 6 proximal femoral parameters measured.

RESULTS

Individuals with adolescent idiopathic scoliosis showed a small but statistically significant decrease in neck shaft angle (average difference=2.58°) and a higher (0.22°) femoral mechanical axis-femoral shaft angle. When the two sides were compared based on curve direction, greater changes in the neck shaft angle and femoral mechanical axis-femoral shaft angle were found on the side of the convexity.

CONCLUSIONS

Patients with adolescent idiopathic scoliosis were found to have a small but significantly lower neck shaft angle and higher femoral mechanical axis-femoral shaft angle, which related to the curve direction. This is postulated to be due to mechanical compensation for altered balance and centre of gravity associated with a scoliosis deformity, although the observed difference likely has negligible clinical effect.

Preoperative pelvic axial rotation: a possible predictor for postoperative coronal decompensation in thoracolumbar/lumbar adolescent idiopathic scoliosis

BACKGROUND

The pelvis as the biomechanical foundation of spine, plays an important role in the balance of the stance and gait through the multi-link spinal-pelvic system. If the pelvic axial rotation (PAR) exists in adolescent idiopathic scoliosis (AIS) patients, it should theoretically have some effects on the body balance.

PURPOSE

To explore the probable effects of preoperative PAR on the spinal balance in coronal plane in AIS patients with main thoracolumbar/lumbar (TL/L) curve after posterior spinal instrumentation.

METHODS

Thirty-eight AIS patients (age: 15 ± 1.5 years) with main TL/L curve (51° ± 6.2°) were recruited retrospectively into this study. The mean follow-up period was 27 months (24-36 months). Standing full spine posteroanterior radiographs were taken preoperatively, 3 month and 1 year postoperatively, and at last follow-up. The convex/concave ratio (CV/CC ratio) of the anterior superior iliac spine laterally and the inferior ilium at the sacroiliac joint medially was measured on posteroanterior radiographs. According to the preoperative CV/CC ratios, the patients were divided into two groups: normal group (N-group: 0.95 ≤ CV/CC ≤ 1.05); and the asymmetrical group (A-group: CV/CC < 0.95, or >1.05).

RESULTS

In all the patients, the 3-month-postoperative CV/CC ratio (1.026 ± 0.087) was significantly different from the preoperative CV/CC ratio (0.969 ± 0.095, P < 0.001), indicating that the pelvis had rotated in the opposite direction of the corrective derotation load applied to the TL/L spine after surgery. No significant change was found in the CV/CC ratio from 3-month-postoperative to the last follow-up (1.013 ± 0.103, P > 0.05). There was no significant difference in the demographic, phenotypic, and treatment variables between the N- (n = 16) and A-groups (n = 22) (P > 0.05). However, more coronal decompensation occurred in the A-group after surgery (36.4 vs. 0.0 %, P = 0.013): two patients having trunk translation, three having lower instrumented vertebra (LIV) translation, and one having LIV tilt; meanwhile, one patient having both LIV translation and LIV tilt, and one having both trunk translation and LIV tilt.

CONCLUSIONS

The present study confirmed the existence of PAR in AIS patients, and indicated that the pelvis would experience an active rebalancing in the transverse plane within 3 months after spinal correction, and since then, its position would remain stable. Moreover, TL/L-AIS patients with preoperative asymmetrical PAR probably had greater risk of coronal decompensation postoperatively.

Anatomical study of the pelvis in patients with adolescent idiopathic scoliosis

Standing posterior-anterior (PA) radiographs from our clinical practice show that the concave and convex ilia are not always symmetrical in patients with adolescent idiopathic scoliosis (AIS). Transverse pelvic rotation may explain this observation, or pelvic asymmetry may be responsible. The present study investigated pelvic symmetry by examining the volume and linear measurements of the two hipbones in patients with AIS. Forty-two female patients with AIS were recruited for the study. Standing PA radiographs (covering the thoracic and lumbar spinal regions and the entire pelvis), CT scans and 3D reconstructions of the pelvis were obtained for all subjects. The concave/convex ratio of the inferior ilium at the sacroiliac joint medially (SI) and the anterior superior iliac spine laterally (ASIS) were measured on PA radiographs. Hipbone volumes and several distortion and abduction parameters were measured by post-processing software. The concave/convex ratio of SI-ASIS on PA radiographs was 0.97, which was significantly < 1 (P < 0.001). The concave and convex hipbone volumes were comparable in patients with AIS. The hipbone volumes were 257.3 ± 43.5 cm(3) and 256.9 ± 42.6 cm(3) at the concave and convex sides, respectively (P > 0.05). Furthermore, all distortion and abduction parameters were comparable between the convex and concave sides. Therefore, the present study showed that there was no pelvic asymmetry in patients with AIS, although the concave/convex ratio of SI-ASIS on PA radiographs was significantly < 1. The clinical phenomenon of asymmetrical concave and convex ilia in patients with AIS in preoperative standing PA radiographs may be caused by transverse pelvic rotation, but it is not due to developmental asymmetry or distortion of the pelvis.