Artikel
Flexor Tendon Morphology, a Prerequisite for Triggering at the A1 Pulley
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Autoren
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P.N. Broer
- NYU, Plastische Chirurgie, New York, United States
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S. Buonocore
- Yale University, Plastic Surgery, New Haven, United States
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R. Shaw
- Yale University, Plastic Surgery, New Haven, United States
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G. Thomson
- Yale University, Plastic Surgery, New Haven, United States
| Veröffentlicht: | 10. September 2012 |
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Gliederung
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Introduction: The vast majority of triggering in the digits occurs at the A1 pulley. It is unclear if this is due to an intrinsic property of the A1 pulley, or if other factors are responsible for these findings. We have observed a segment of the flexor tendons just distal to the A1 pulley with increased volume compared to other segments along the length of the tendon. We hypothesize that this predisposes to triggering at the A1 pulley, vs. other pulleys in the retinacular system.
Materials and Methods: A previously developed triggering model in a cadaveric hand was used. 4mm wide cable ties were inserted around the A1, A2 and A3 pulleys of each digit. The minimal amount of force required to initiate triggering was applied to the tie & recorded for each testing scenario. Twenty digits were tested in a tensile testing machine. Next the tendons were sectioned at 4 points along the length of the tendon, including proximal and distal to the A1 pulley, and distal to the A2 and A3 pulleys . Tendon and pulley surface area & volume was calculated using ImageJ software. Appropriate statistical analysis was performed.
Results: Triggering was consistently reproduced at the A1 pulley in all digits studied, this occurred with the lowest compressive force compared to the A2 & A3 pulleys. Triggering at the A2, oblique & A3 pulleys was sporadic, the forces required for triggering at these pulleys were significantly increased compared to forces needed to initiate triggering at the A1 pulley. Volume analysis of the flexor tendons showed a statistically significant increase in volume in the region just distal to the A1 pulley compared to the other areas studied. Pulley analysis showed that the A1 pulley though significantly shorter in length, had a surface area similar to the A2 pulley.
Conclusions:
- Triggering is consistently reproduced at the A1 pulley with the lowest degree of compressive force.
- Tendon morphology, including a section of tendon distal to the A1 pulley with significantly increased volume likely predisposes to triggering at the A1 pulley.
