[Changes in the lengths of the gluteus medius and gluteus minimus muscles with trochanteric transfer following pelvic support osteotomy: a biomechanical study].
OBJECTIVE
Using a synthetic bone model, we investigated changes in the muscle length of the gluteus medius and gluteus minimus following trochanteric osteotomy and pelvic support osteotomy (PSO) and compared the results with those of traditional PSO.


METHODS
On two pelvises and four femurs, the lengths of the gluteus medius and gluteus minimus were measured in the following circumstances, with the hips in neutral position and in 45 degrees of flexion: (i) alignment of the hip joint with normal congruency; (ii) dislocated hip joint; (iii) following an osteotomy 2.5 cm below the lesser trochanter and stabilization with an angulation of 45 degrees of abduction; (iv) the insertion point was then moved 2 cm distally and 1 cm laterally, simulating a translation osteotomy of the greater trochanter.


RESULTS
The muscle lengths increased with PSO compared to those of the dislocated hips (p<0.0001). Following distal and lateral translation osteotomy, the lengths significantly exceeded those obtained with traditional osteotomy (p<0.002), but were significantly less than those in the neutral position (p<0.001). Measurements in 45 degrees of flexion yielded similar results. Normal lengths could not be obtained in any of the procedures.


CONCLUSIONS
Distal and lateral translation osteotomy following traditional PSO seems to increase the length of the abductor moment arm more than that obtained by traditional PSO alone.
Inan
Muharrem
M
Department of Orthopedics and Traumatology, Medicine Faculty of Inönü University, Malatya, Turkey. minan@inonu.edu.tr
Mahar
Andrew
A
Swimmer
Troy
T
Tomlinson
Tucker
T
Wenger
Dennis R
DR
D001696:Biomechanical Phenomena; D002081:Buttocks; D016267:External Fixators; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006801:Humans; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D010027:Osteotomy; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D011859:Radiography