The Journal of Bone and Joint Surgery (American). 2005;87:2246-2252.
doi:10.2106/JBJS.D.02727
© 2005 The Journal of Bone and Joint Surgery, Inc.
Evaluation of the Gluteus Medius Muscle After a Pelvic Support Osteotomy to Treat Congenital Dislocation of the Hip
Muharrem Inan, MD1,
Alpay Alkan, MD1,
Ahmet Harma, MD1 and
Kadir Ertem, MD1
1 Departments of Orthopaedics (M.I., A.H., and K.E.) and Radiology (A.A.),
Turgut Ozal Medical Center, Inonu University Medical Faculty, 44069 Malatya,
Turkey. E-mail address for M. Inan:
minan{at}inonu.edu.tr
Investigation performed at the Departments of Orthopaedics and
Radiology, Turgut Ozal Medical Center, Inonu University Medical Faculty,
Malatya, Turkey
The authors did not receive grants or outside funding in support of their
research or preparation of this manuscript. They did not receive payments or
other benefits or a commitment or agreement to provide such benefits from a
commercial entity. No commercial entity paid or directed, or agreed to pay or
direct, any benefits to any research fund, foundation, educational
institution, or other charitable or nonprofit organization with which the
authors are affiliated or associated.
Background: Many authors have reported that the pelvic support
osteotomy prevents a Trendelenburg gait by restoring the biomechanics of the
abductor muscle in patients with congenital dislocation of the hip. However,
we are not aware of any studies in which the hip abductor muscles were
examined following pelvic support osteotomy. The purpose of this study was,
first, to use magnetic resonance imaging to measure alterations in the length
and volume of the gluteus medius muscle after pelvic support osteotomy and,
second, to determine which factors influence the results of the Trendelenburg
test.
Methods: Eleven patients with a history of congenital hip
dislocation who had been treated with a pelvic support osteotomy were examined
clinically with the Harris hip score and the Trendelenburg test,
radiographically to measure limb-length discrepancy and valgus angulation of
the proximal part of the femur, and with magnetic resonance imaging to measure
changes in the gluteus medius length and volume.
Results: The pelvic support osteotomy achieved a functional and
painless hip in all eleven patients. Five of the eleven patients had a
persistently positive Trendelenburg gait at the time of the last follow-up
visit, at an average of three years after the osteotomy. The muscle volumes
were restored to 43% to 89% of the muscle volumes on the normal contralateral
side, and the postoperative muscle volume correlated significantly with the
result of the Trendelenburg test (r = -0.63; p = 0.03). There was a positive
association between age and the result of the Trendelenburg test (p = 0.01):
four of the five patients who had a positive test were at least thirty-one
years of age at the time of the operation. There was no correlation between
the Trendelenburg test and the change in the length of the gluteus medius
muscle, which averaged 19.2 mm in the patients with a positive test and 19.3
mm in those with a negative test.
Conclusions: Patient age at the time of the operation and the
postoperative change in the volume of the gluteus medius muscle have a
significant influence on the result of the Trendelenburg test after a pelvic
support osteotomy. Moreover, our study demonstrated that restoration of the
muscle volume after a pelvic support osteotomy is not sufficient to prevent a
Trendelenburg gait in older patients with congenital dislocation of the
hip.
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.

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