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The Effect of Pulling Angle on Rotator Cuff Mechanical Properties in a Canine In Vitro Model
Qian Liu1, Jun Qi2, Weihong Zhu1
1Department of Orthopaedics, The Second Xiangya Hospital, Central South University, Changsha 410011, China.
Bioengineering (Basel, Switzerland)
|May 27, 2023
Summary
The pulling angle significantly impacts rotator cuff tendon strength, with functional pulls weakening intact tendons. However, the modified Mason-Allen repair technique mitigates this effect, restoring mechanical properties.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Veterinary Medicine
Background:
- Rotator cuff tears are common injuries, often requiring surgical repair.
- Understanding the biomechanical properties of tendons under different loading conditions is crucial for successful repair outcomes.
- The infraspinatus tendon's mechanical behavior is influenced by its anatomical orientation and loading forces.
Purpose of the Study:
- To investigate the effect of pulling angle on the time-zero mechanical properties of intact and repaired canine infraspinatus tendons.
- To compare the biomechanical performance of tendons under functional (135°) versus anatomic (70°) pulling angles.
- To evaluate the efficacy of the modified Mason-Allen technique in restoring tendon mechanical properties under varying loads.
Main Methods:
- Utilized 36 canine shoulder samples for in vitro biomechanical testing.
- Intact infraspinatus tendons (n=20) were tested under functional and anatomic pulling angles.
- Transected tendons (n=16) were repaired using the modified Mason-Allen technique and then tested under the same angles.
- Performed load-to-failure testing to determine ultimate failure load, ultimate stress, and stiffness.
Main Results:
- Intact tendons under functional pull exhibited significantly lower ultimate failure load and stress compared to those under anatomic pull (p < 0.05).
- Repaired tendons using the modified Mason-Allen technique showed no significant differences in mechanical properties between functional and anatomic pulling groups.
- Pulling angle significantly influenced the biomechanical properties of intact rotator cuff tendons in this canine model.
Conclusions:
- The angle of pull critically affects the mechanical integrity of intact rotator cuff tendons, potentially predisposing them to injury under functional loads.
- The modified Mason-Allen rotator cuff repair technique effectively restores tendon mechanical properties, overcoming the detrimental effects of functional pulling angles.
- This study highlights the importance of considering biomechanical forces in rotator cuff repair strategies.
