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Structural Properties of the Native Ligamentum Teres.

Philippon MJ, Rasmussen MT, Turnbull TL, Trindade CA, Hamming MG, Ellman MB, Harris M, LaPrade RF, Wijdicks CA - Orthop J Sports Med (2014)

Bottom Line: The human LT had a mean ultimate failure load of 204 N.Therefore, the results of this investigation, combined with recent biomechanical and outcomes studies, suggest that special consideration should be given to preserving the structural and corresponding biomechanical integrity of the LT during surgical intervention.The LT may be more important as a static stabilizer of the hip joint than previously recognized.

View Article: PubMed Central - PubMed

Affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA. ; The Steadman Clinic, Vail, Colorado, USA.

ABSTRACT

Background: A majority of studies investigating the role of the ligamentum teres (LT) have focused primarily on anatomical and histological descriptions. To date, however, the structural properties of the LT have yet to be fully elucidated.

Purpose: To investigate the structural properties of the native LT in a human cadaveric model.

Study design: Descriptive laboratory study.

Methods: A total of 12 human cadaveric hemipelvises (mean age, 53.6 years; range, 34-63 years) were dissected free of all extra-articular soft tissues to isolate the LT and its acetabular and femoral attachments. A dynamic tensile testing machine distracted each femur in line with the fibers of the LT at a displacement-controlled rate of 0.5 mm/s. The anatomic dimensions, structural properties, and modes of failure were recorded.

Results: The LT achieved a mean yield load of 75 N and ultimate failure load of 204 N. The LT had mean lengths of 38.0 and 53.0 mm at its yield and failure points, respectively. The most common (75% of specimens) mechanism of failure was tearing at the fovea capitis. On average, the LT had a linear stiffness of 16 N/mm and elastic modulus of 9.24 MPa. The mean initial length and cross-sectional area were 32 mm and 59 mm(2), respectively.

Conclusion: The human LT had a mean ultimate failure load of 204 N. Therefore, the results of this investigation, combined with recent biomechanical and outcomes studies, suggest that special consideration should be given to preserving the structural and corresponding biomechanical integrity of the LT during surgical intervention.

Clinical relevance: The LT may be more important as a static stabilizer of the hip joint than previously recognized. Further studies are recommended to investigate the appropriate indications to perform surgical repair or reconstruction of the LT for preservation of hip stability and function.

No MeSH data available.


Related in: MedlinePlus

Biomechanical testing setup for a right hip. The femur was attached to the actuator (A) of the dynamic tensile testing machine while secured within a custom ball and socket alignment fixture (B). Similarly, the acetabulum was secured within a custom ball and socket alignment fixture (C) rigidly mounted to the base platform. The use of ball and socket fixtures for alignment positioning ensured that the tensile force was applied in line with the fibers of the ligamentum teres, placing these fibers in a position of maximal vulnerability throughout testing.
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fig1-2325967114561962: Biomechanical testing setup for a right hip. The femur was attached to the actuator (A) of the dynamic tensile testing machine while secured within a custom ball and socket alignment fixture (B). Similarly, the acetabulum was secured within a custom ball and socket alignment fixture (C) rigidly mounted to the base platform. The use of ball and socket fixtures for alignment positioning ensured that the tensile force was applied in line with the fibers of the ligamentum teres, placing these fibers in a position of maximal vulnerability throughout testing.

Mentions: Structural properties of the LT were evaluated in response to a load-to-failure protocol using a dynamic tensile testing system (ElectroPuls E10000; Instron). Measurement error of the testing system was certified by Instron to be less than or equal to ±0.01 mm and ±0.3% of the indicated force. The potted acetabulum was secured within a custom ball and socket fixture rigidly clamped to the base platform of the testing system, and the potted femur was similarly secured to the actuator of the testing system (Figure 1). The location of the LT footprint on the femoral head and acetabulum was observed during pilot testing to vary considerably; therefore, custom ball and socket fixtures were fabricated to provide increased degrees of freedom during alignment positioning and ensured that the tensile force was applied in line with the fibers of the LT, placing these fibers in a position of maximal vulnerability throughout testing.


Structural Properties of the Native Ligamentum Teres.

Philippon MJ, Rasmussen MT, Turnbull TL, Trindade CA, Hamming MG, Ellman MB, Harris M, LaPrade RF, Wijdicks CA - Orthop J Sports Med (2014)

Biomechanical testing setup for a right hip. The femur was attached to the actuator (A) of the dynamic tensile testing machine while secured within a custom ball and socket alignment fixture (B). Similarly, the acetabulum was secured within a custom ball and socket alignment fixture (C) rigidly mounted to the base platform. The use of ball and socket fixtures for alignment positioning ensured that the tensile force was applied in line with the fibers of the ligamentum teres, placing these fibers in a position of maximal vulnerability throughout testing.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4555531&req=5

fig1-2325967114561962: Biomechanical testing setup for a right hip. The femur was attached to the actuator (A) of the dynamic tensile testing machine while secured within a custom ball and socket alignment fixture (B). Similarly, the acetabulum was secured within a custom ball and socket alignment fixture (C) rigidly mounted to the base platform. The use of ball and socket fixtures for alignment positioning ensured that the tensile force was applied in line with the fibers of the ligamentum teres, placing these fibers in a position of maximal vulnerability throughout testing.
Mentions: Structural properties of the LT were evaluated in response to a load-to-failure protocol using a dynamic tensile testing system (ElectroPuls E10000; Instron). Measurement error of the testing system was certified by Instron to be less than or equal to ±0.01 mm and ±0.3% of the indicated force. The potted acetabulum was secured within a custom ball and socket fixture rigidly clamped to the base platform of the testing system, and the potted femur was similarly secured to the actuator of the testing system (Figure 1). The location of the LT footprint on the femoral head and acetabulum was observed during pilot testing to vary considerably; therefore, custom ball and socket fixtures were fabricated to provide increased degrees of freedom during alignment positioning and ensured that the tensile force was applied in line with the fibers of the LT, placing these fibers in a position of maximal vulnerability throughout testing.

Bottom Line: The human LT had a mean ultimate failure load of 204 N.Therefore, the results of this investigation, combined with recent biomechanical and outcomes studies, suggest that special consideration should be given to preserving the structural and corresponding biomechanical integrity of the LT during surgical intervention.The LT may be more important as a static stabilizer of the hip joint than previously recognized.

View Article: PubMed Central - PubMed

Affiliation: Steadman Philippon Research Institute, Vail, Colorado, USA. ; The Steadman Clinic, Vail, Colorado, USA.

ABSTRACT

Background: A majority of studies investigating the role of the ligamentum teres (LT) have focused primarily on anatomical and histological descriptions. To date, however, the structural properties of the LT have yet to be fully elucidated.

Purpose: To investigate the structural properties of the native LT in a human cadaveric model.

Study design: Descriptive laboratory study.

Methods: A total of 12 human cadaveric hemipelvises (mean age, 53.6 years; range, 34-63 years) were dissected free of all extra-articular soft tissues to isolate the LT and its acetabular and femoral attachments. A dynamic tensile testing machine distracted each femur in line with the fibers of the LT at a displacement-controlled rate of 0.5 mm/s. The anatomic dimensions, structural properties, and modes of failure were recorded.

Results: The LT achieved a mean yield load of 75 N and ultimate failure load of 204 N. The LT had mean lengths of 38.0 and 53.0 mm at its yield and failure points, respectively. The most common (75% of specimens) mechanism of failure was tearing at the fovea capitis. On average, the LT had a linear stiffness of 16 N/mm and elastic modulus of 9.24 MPa. The mean initial length and cross-sectional area were 32 mm and 59 mm(2), respectively.

Conclusion: The human LT had a mean ultimate failure load of 204 N. Therefore, the results of this investigation, combined with recent biomechanical and outcomes studies, suggest that special consideration should be given to preserving the structural and corresponding biomechanical integrity of the LT during surgical intervention.

Clinical relevance: The LT may be more important as a static stabilizer of the hip joint than previously recognized. Further studies are recommended to investigate the appropriate indications to perform surgical repair or reconstruction of the LT for preservation of hip stability and function.

No MeSH data available.


Related in: MedlinePlus