What are the sport-specific biomechanics of the hip relevant to hip fractures?

Updated: Jan 08, 2019
  • Author: Naveenpal S Bhatti, MD; Chief Editor: Sherwin SW Ho, MD  more...
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Answer

The ball-and-socket joint provides most of the inherent stability of the hip joint, while allowing for a large range of motion. Additional stability is provided by the thick capsule and strong ligamentous structures that actually enforce the capsule, namely the iliofemoral, pubofemoral, and ischiofemoral ligaments. These ligaments are taut with internal rotation, which limits motion, and become lax with external rotation.

Motion about the hip occurs in the sagittal, frontal, and transverse planes. During normal gait, motion occurs in all 3 planes, and normal activities occur within the range of 120 º flexion, 20 º extension, 40 º abduction, 25 º adduction, and 45 º external and internal rotation.

The biomechanics of the neck-shaft angle, which averages 135 º and 10-15 º of anteversion, allows for a unique arrangement. This permits angular movements of the thigh to be converted to rotatory hip motion.


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