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Published on: January 29, 2018
Defining the relationship between the hip, pelvis, and lumbar spine
Emily S Mills1,2, Mary K Richardson1, Jennifer C Wang1
1Department of Orthopaedic Surgery, Keck School of Medicine of USC, 1200 N State St GH 3900, Los Angeles, CA 90033, United States.
Hip flexion significantly impacts pelvic tilt and lumbar spine movement, revealing strong correlations in spinopelvic biomechanics. Understanding these relationships is crucial for advancing spine research.
Area of Science:
- Biomechanics
- Spine Surgery
- Orthopedics
Background:
- The synchronous movement of the hip, pelvis, and lumbar spine is recognized.
- The precise biomechanical relationship between these structures remains undefined.
Purpose of the Study:
- To define the biomechanical relationship between the hip, pelvis, and lumbar spine.
Main Methods:
- Fifty healthy young adults (18-35 years) participated.
- Three lateral radiographs (standing, seated, flexed-forward seated) were analyzed.
- Measurements included sacral slope (SS), pelvic-femoral angle (PFA), and lumbar lordosis (LL), with changes (ΔSS, ΔPFA, ΔLL) calculated.
Main Results:
- A 1° increase in hip flexion correlated with a 0.84° decrease in lumbar flexion (R=-0.75, p<.001).
- ΔPFA was strongly negatively correlated with ΔSS (R=-0.85, p<.001).
- ΔSS was strongly positively correlated with ΔLL (R=0.85, p<.001).
Conclusions:
- Hip, pelvis, and lumbar spine motion are highly correlated.
- Pelvic tilt and lumbar spine flexion adjust to maintain posture during hip flexion.
- These defined relationships are essential for spinopelvic biomechanics research.
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