Anatomy of piriformis, obturator internus and obturator externus: Implications for the posterior surgical approach to the hip
Date
2010
Authors
Solomon, L.
Lee, Y.
Callary, S.
Beck, M.
Howie, D.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Journal of Bone and Joint Surgery: British Volume, 2010; 92B(9):1317-1324
Statement of Responsibility
L. B. Solomon, Y. C. Lee, S. A. Callary, M. Beck, D. W. Howie
Conference Name
Abstract
We dissected 20 cadaver hips in order to investigate the anatomy and excursion of the trochanteric muscles in relation to the posterior approach for total hip replacement. String models of each muscle were created and their excursion measured while the femur was moved between its anatomical position and the dislocated position. The position of the hip was determined by computer navigation. In contrast to previous studies which showed a separate insertion of piriformis and obturator internus, our findings indicated that piriformis inserted onto the superior and anterior margins of the greater trochanter through a conjoint tendon with obturator internus, and had connections to gluteus medius posteriorly. Division of these connections allowed lateral mobilisation of gluteus medius with minimal retraction. Analysis of the excursion of these muscles revealed that positioning the thigh for preparation of the femur through this approach elongated piriformis to a maximum of 182%, obturator internus to 185% and obturator externus to 220% of their resting lengths, which are above the thresholds for rupture of these muscles. Our findings suggested that gluteus medius may be protected from overstretching by release of its connection with the conjoint tendon. In addition, failure to detach piriformis or the obturators during a posterior approach for total hip replacement could potentially produce damage to these muscles because of over-stretching, obturator externus being the most vulnerable.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
Copyright © 2010 by British Editorial Society of Bone and Joint Surgery