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Semitendinosus and patellar tendons shear modulus evaluation by supersonic shearwave imaging elastography
C R C Fontenelle1, P Mannarino1,2, F B D O Ribeiro1
1Department of Orthopaedic Surgery, UFRJ, Clementino Fraga Filho University Hospital, Rio de Janeiro, Brazil.
Clinical Physiology and Functional Imaging
|February 8, 2018
Summary
The semitendinosus tendon has higher stiffness than the patellar tendon, indicating it may be a better choice for anterior cruciate ligament reconstruction grafts due to its strength and less elastic behavior.
Area of Science:
- Biomechanics
- Musculoskeletal imaging
- Orthopedic surgery
Background:
- Shear modulus (μ) quantifies tissue stiffness and predicts tendon failure force.
- Tendon stress patterns vary with knee flexion angle (0° vs. 80°).
- The relationship between semitendinosus (ST) and patellar tendon (PT) shear modulus across different knee positions is not well understood.
Purpose of the Study:
- To investigate the shear modulus (μ) of the semitendinosus (ST) and patellar tendon (PT) at 0° (K0) and 80° (K80) knee flexion.
- To compare the relative shear modulus indexes of ST and PT in relaxed and tensioned states.
Main Methods:
- Supersonic shear wave imaging (SSI) elastography was used to measure shear modulus (μ) in 18 healthy males.
- Measurements were taken at 0° (K0) and 80° (K80) knee flexion.
- Relative shear modulus indexes were calculated for relaxed (IR) and tensioned (IT) conditions.
Main Results:
- Semitendinosus tendon shear modulus (μST) was significantly higher than patellar tendon shear modulus (μPT) in both K0 and K80 positions.
- Average μST-K0 = 197.62 kPa, μST-K80 = 77.76 kPa.
- Average μPT-K0 = 23.45 kPa, μPT-K80 = 113.92 kPa.
- Relative index for relaxed tendons (IR = μST-K80/μPT-K0) was 3.63 ± 1.50.
- Relative index for tensioned tendons (IT = μST-K0/μPT-K80) was 2.00 ± 0.96 (P<0.05).
Conclusions:
- Semitendinosus tendon exhibits significantly higher stiffness than the patellar tendon under both relaxed and tensioned conditions.
- This suggests ST grafts may offer greater ultimate force to failure and reduced elasticity compared to PT grafts.
- These findings can inform graft selection for anterior cruciate ligament reconstruction.
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