Sagittal Spinal-pelvic Alignment in Patients with Crowe Type IV Developmental Dysplasia of the Hip
Abstract Background The compensatory mechanisms of the spine, pelvis, and lower limbs are essential to maintaining an upright posture. The effect of a high dislocated dysplastic hip on spinal-pelvic alignment has not been well described. The aim of this study was to investigate the sagittal spinal-pelvic alignment in patients with Crowe type IV developmental dysplasia of the hip(DDH). Methods A prospective study was conducted from July 2016 to December 2017, and 49 consecutive patients with unilateral or bilateral high dislocated dysplastic hips were enrolled. Forty-nine sex- and age-matched asymptomatic healthy adults were also recruited as a control group. The sacral slope (SS), lumbar lordosis (LL), spino-sacral angle (SSA), C7 tilt (C7T), and sagittal vertical axis (SVA[C7])were measured on lateral whole spine radiographs. The presence of low back pain and visual analogue scale (VAS) scores were recorded. Results Patients with high dislocated dysplastic hips showed significantly greater SS(47.5±7.5° vs. 40.4±6.7°, p<0.001), LL(-63.7±9.2° vs. -53.3±11.5°, P<0.001), SSA(141.8°±7.2° vs. 130.6±7.9°, p<0.001), C7T(93.9±3.6° vs. 91.1±3.7°, P<0.001), and lower SVA(C7) (-16mm[-95-45] vs. 6.4mm[-52-47], p<0.001) compared to normal controls. Patients with bilateral high dislocated dysplastic hips also exhibited larger SS, LL, SSA, and C7T and a smaller SVA(C7) than those of patients with unilateral hip dysplasia. 63.2% of the patients with high dislocated dysplastic hips reported low back pain. Conclusion Patients with Crowe type IV DDH exhibited abnormal spinal-pelvic alignment characterized by anterior pelvic tilt, lumbar hyperlordosis, and a backward-leaning trunk. Bilateral dislocated dysplastic hips had a greater impact on spinal-pelvic alignment than unilateral dislocated dysplastic hips.