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Surgical Retrieval, Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications
Published on: April 30, 2014
Viscoelasticity and temperature variations decrease tension and stiffness of hamstring tendon grafts following
William J Ciccone1, Derek R Bratton, David M Weinstein
1The Medical Education and Research Institute of Colorado, 3920 North Union Boulevard, Suite 210, Colorado Springs, CO 80907, USA.
Summary
Hamstring tendon graft tension and stiffness significantly decrease after anterior cruciate ligament reconstruction due to stress relaxation and temperature changes, potentially increasing knee laxity.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Biomaterials Science
Background:
- Anterior cruciate ligament (ACL) reconstruction commonly uses hamstring tendon grafts.
- Grafts undergo stress relaxation and temperature changes from operating room to body temperature post-surgery.
- The study investigated the impact of these factors on graft properties.
Purpose of the Study:
- To evaluate the changes in tension and stiffness of semitendinosus and gracilis tendon grafts after ACL reconstruction.
- To determine the effects of stress relaxation and temperature increase on graft biomechanics.
Main Methods:
- Hamstring tendons (semitendinosus and gracilis) from cadavers were used to create double-strand grafts.
- Grafts were loaded to 65 N at 20°C, with tension and stiffness measured after initial stress relaxation and subsequent temperature increase to 34°C.
- Measurements were compared to baseline values immediately after reconstruction.
Main Results:
- Stress relaxation reduced graft tension to ~50% and stiffness to ~80% of initial values.
- Increasing temperature further decreased tension to ~40% and stiffness to ~70% of initial values.
- All observed changes in tension and stiffness were statistically significant (p < 0.01).
Conclusions:
- Postoperative graft tension and stiffness are not maintained due to stress relaxation and temperature rise.
- These biomechanical changes may contribute to increased knee laxity following ACL reconstruction.
- Further research may explore methods to mitigate these graft property degradations.
