Content
Abstract of
the article: Wenger D et al. The mechanical properties of the ligamentum teres:
a pilot study to assess its potential for improving stability in children’s hip
surgery (2007). The authors demonstrated in the experiment that the strength of
the ligamentum capitis femoris (LCF) is sufficient to ensure early stability
during hip joint reconstruction in children. The text in Russian is available
at the following link: 2007WengerD_OkaetR.
Abstract
The anatomic and histological characteristics of the ligamentum teres and its vascular contributions to the femoral head have been well described. The function of the ligamentum teres remains poorly understood. Although excision is the current standard in treating complete developmental hip dysplasia, we developed an interest in maintaining, shortening, and reattaching the ligament to assure early postoperative stability in developmental hip dysplasia. To analyze its potential for providing hip joint stability, we investigated the biomechanical properties of the ligamentum teres in an in vitro porcine model. Six immature porcine hips were dissected, with the proximal femur and acetabular anatomy kept intact, isolating the ligamentum teres. Specimens were loaded in tension using custom fixation rigs at 0.5 mm/s in line with the fibers. Data for displacement and force were collected and sampled at 10 Hz for duration of each test. The ligamentum teres failed in a stepwise fashion. The mean ultimate load to failure was 882 +/- 168 N. Mean stiffness and failure stress were calculated as 86 +/- 25 N/mm and 10 +/- 2 MPa, respectively. The biomechanical function of the ligamentum teres is not inconsequential. We found the ultimate load of the ligamentum teres in the porcine model to be similar to those reported for the human anterior cruciate ligament. The strength of the ligamentum teres may confirm its potential for providing early stability in childhood hip reconstructions. In the setting of dysplasia, the preservation and the transfer of the ligamentum teres to augment stability should be considered as an adjunct to open reduction.
Conclusion
In this
study, we found the ligamentum teres to have material properties similar to
those of other ligaments. Its biomechanical function is not inconsequential,
and it likely contributes significantly to the stabilization of the hip joint.
In the setting of dysplasia, the preservation and the transfer of the
ligamentum teres to augment stability should be considered as an adjunct to
open reduction. The tradition of excising the ligament along with the fatty
pulvinar had an important role in the early methods developed to assure a deep,
stable reduction without obstructions. New understanding and advanced surgical
approaches may allow this ligament to be maintained and used as an aid to
assuring early postoperative stability in childhood hip reconstructions.
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Wenger D,
Firoz Miyanji F, Mahar A, Okaet R. The mechanical properties of the ligamentum
teres: a pilot study to assess its potential for improving stability in
children’s hip surgery. J Pediatr Orthop. 2007;27(4)408-10. doi: 10.1097/01.bpb.0000271332.66019.15. journals.lww.com , pubmed.ncbi.nlm.nih.gov
Methodology
Six
immature porcine hips (mean age, 12 months) were dissected free of soft tissue,
muscle, and capsular attachments. The proximal femur and acetabular anatomy
were kept intact to isolate the ligamentum teres. The thickness of the ligament
was measured at the midsubstance using digital calipers accurate to within 0.01
mm (Chicago Brand, Chicago, Ill). The superior aspect of the acetabular
component was sectioned to allow for tensile testing in line with the fibers and
to allow for potential femoral dislocation. The proximal femur and remaining
acetabulum were secured using 2-part epoxy resin (Bondo-Marhyde, Atlanta, Ga)
and fixed within an MTS 858 biaxial load frame (MTS, Eden Prairie, Minn) using
custom fixation rigs. The specimens were loaded in tension at 0.5 mm/s in line
with the fibers of the ligamentum teres (Fig. 1). Tests were stopped when the
load-displacement curve demonstrated a reduction in tensile force.
Dennis Wenger – Department
of Orthopedics, Rady Children's Hospital-San Diego, CA 92123, USA.
Firoz Miyanji – Department
of Orthopedics, Rady Children's Hospital-San Diego, CA 92123, USA.
Andrew Mahar – Department
of Orthopedics, Rady Children's Hospital-San Diego, CA 92123, USA.
Richard Oka
– Department of Orthopedics, Rady Children's Hospital-San Diego, CA 92123,
USA.
ligamentum capitis femoris, ligamentum teres, ligament of head of femur, plastic surgery, reconstruction, experiment, strength, mechanical properties, animals, pig
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