Acetabular Loading in Active Abduction

• Published in: IEEE transactions on neural systems and rehabilitation engineering 2007-06, Vol.15 (2), p.252-257
• Main Authors: Kristan, Ane, Mavcic, Bla, Cimerman, Matej, Iglic, Ale, Tonin, Martin, Slivnik, Toma, Kralj-Iglic, Veronika, Daniel, Matej
• Format: Article
• Language: English
• Subjects: Acetabular fracture; Acetabulum - physiology; Biomechanics; Bones; Compressive Strength - physiology; Computer Simulation; Hip; hip contact stress; Hip joint; Hip Joint - physiology; Humans; Laboratories; Leg; Mathematical model; Mathematical models; Medical treatment; Models, Biological; Movement - physiology; Muscle Contraction - physiology; Muscle, Skeletal - physiology; Osteoarthritis; Postural Balance - physiology; Posture - physiology; Range of Motion, Articular; rehabilitation; Stress; Stress, Mechanical; Surgery; Tensile Strength - physiology; Weight-Bearing - physiology
• ISSN: 1534-4320; 1558-0210
• DOI: 10.1109/TNSRE.2007.897023

Operative fixation of fragments in acetabular fracture treatment is not strong enough to allow weight bearing before the bone is healed. In some patients, even passive or active nonweight-bearing exercises could lead to dislocation of fragments and posttraumatic osteoarthritis. Therefore, early rehabilitation should avoid loading the acetabulum in the regions of fracture lines. The aim of the paper is to estimate acetabular loading in nonweight-bearing upright, supine, and side-lying leg abduction. Three-dimensional mathematical models of the hip joint reaction force and the contact hip stress were used to simulate active exercises in different body positions. The absolute values of the hip joint reaction force and the peak contact hip stress are the highest in unsupported supine abduction (1.3 MPa) and in side-lying abduction (1.2 MPa), lower in upright abduction (0.5 MPa), and the lowest in supported supine abduction (0.2 MPa). All body positions the hip joint reaction force and the peak contact hip stress are the highest in the posterior-superior quadrant of acetabulum, followed by anterior-superior quadrant, posterior-inferior quadrant, and finally anterior-inferior quadrant. Spatial distribution of the average acetabular loading shows that early rehabilitation should be planned according to location of the fracture lines.