TY - JOUR
T1 - Lateral acetabular rotation improves anterior hip subluxation
AU - Rab, George T
PY - 2007
Y1 - 2007
N2 - Surgical reorientation of the acetabulum is used to improve stability of subluxated or dysplastic hips, but the specific mechanical consequences of reorientation have not been quantified. I used a rigid body spring model of the human hip to study the effects of different acetabular positions on hip stability during single-limb stance. The model predicted subluxation direction and magnitude, and the effective joint contact area, as functions of acetabular position. Frontal plane acetabular orientation varied from 20° medial rotation to 50° lateral rotation, corresponding to center-edge angles from 0° to 70°. Sagittal acetabular orientation varied from 45° anterior rotation to 15° posterior rotation. Center-edge angles less than 20° produced progressive anterolateral subluxation, with dislocation occurring when center-edge angles were less than 0°. Lateral subluxation disappeared when center-edge angles were 30° or greater. Anteroposterior subluxation was controlled by anterior or posterior rotation of the acetabulum in the presence of low center-edge angles, but there was no specific position of stability that effectively stabilized the femoral head. Anterior subluxation also was controlled by lateral rotation of the acetabulum. Joint contact area increased 1% for every 3° lateral acetabular rotation. The anterolateral subluxation associated with hip dysplasia can be controlled by acetabular reorientation. Joint contact area will increase, thereby reducing peak joint pressure. Anterior and lateral subluxation can be improved by lateral rotation alone, which may reduce the severity of anterior femoroacetabular impingement after periacetabular osteotomy.
AB - Surgical reorientation of the acetabulum is used to improve stability of subluxated or dysplastic hips, but the specific mechanical consequences of reorientation have not been quantified. I used a rigid body spring model of the human hip to study the effects of different acetabular positions on hip stability during single-limb stance. The model predicted subluxation direction and magnitude, and the effective joint contact area, as functions of acetabular position. Frontal plane acetabular orientation varied from 20° medial rotation to 50° lateral rotation, corresponding to center-edge angles from 0° to 70°. Sagittal acetabular orientation varied from 45° anterior rotation to 15° posterior rotation. Center-edge angles less than 20° produced progressive anterolateral subluxation, with dislocation occurring when center-edge angles were less than 0°. Lateral subluxation disappeared when center-edge angles were 30° or greater. Anteroposterior subluxation was controlled by anterior or posterior rotation of the acetabulum in the presence of low center-edge angles, but there was no specific position of stability that effectively stabilized the femoral head. Anterior subluxation also was controlled by lateral rotation of the acetabulum. Joint contact area increased 1% for every 3° lateral acetabular rotation. The anterolateral subluxation associated with hip dysplasia can be controlled by acetabular reorientation. Joint contact area will increase, thereby reducing peak joint pressure. Anterior and lateral subluxation can be improved by lateral rotation alone, which may reduce the severity of anterior femoroacetabular impingement after periacetabular osteotomy.
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U2 - 10.1097/BLO.0b013e31802c2f23
DO - 10.1097/BLO.0b013e31802c2f23
M3 - Article
C2 - 17106271
AN - SCOPUS:34247579786
SP - 170
EP - 175
JO - Clinical Orthopaedics and Related Research
JF - Clinical Orthopaedics and Related Research
SN - 0009-921X
IS - 456
ER -