Artikel
Testing the avulsion force of the native flexors/extensors tendons of the forearm, and after refixation with single and double row suture fixation technique
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Autoren
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Andreas Lenich
- Orthopädie, Unfall-, Handchirurgie und Sportorthopädie, Helios Klinikum München West, München, Germany
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Philipp Proier
- Technische Universität München, MRI, München, Germany
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Frank Martetschläger
- Technische Universität München, MRI, München, Germany
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Roman Fleer
- Technische Universität München, MRI, München, Germany
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Andreas Imhoff
- Technische Universität München, MRI, München, Germany
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Nicole Fischer
- Biomechanik Institute Arthrex, München, Germany
| Veröffentlicht: | 10. Oktober 2016 |
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Gliederung
Text
Objectives: The function of the forearm and the hand depends on the extensor and flexor muscle group. There are various surgical techniques for refixation of the tendon to the lateral or medial epicondyle. Less re-ruptures and an earlier beginning of use could be the benefit of a more stable fixation.
The aim of this study is to compare a native situation with two different repair techniques, a single row and a double row fixation with suture anchores. Does the DR technique bring a benefit and if yes how much is the difference?
Our hypothesis is, with the Double Row (DR) technique can be reached a higher load to failure than with the Single Row (SR) technique.
Methods: 18 fresh frozen male human specimen under 65 years with no elbow trauma or other operation in the elbow were used.
On the extensor side the carpi ulnaris, carpi radialis brevis, extensor digitorum and digiti minimi, on the flexor side the carpi radialis, carpi ulnaris, palmaris longus and flexor digitorum superficialis were preparated.
The following anchors were used:
- Single Row (SR)
- 2x PEEK Suture Tak® 3 mm with #2 FiberWire® and #2 TigerWire®
- Double Row (DR)
- 2x PEEK Suture Tak® 3 mm with #2 FiberWire® and #2 TigerWire®)
- 1x PEEK SwiveLock®, 3.5 mm
Testing Protokoll: Agonist load according to Brand et al. 1981 and 1988 was calculated as max. cyclic loading for each side. For the tendon of the flexors a min. force of 15N with 1Hz and 50 cycles was applied. Each specimen was run 10 load levels with in the end 500cycles increasing stepwise up to 150N. For the tendon of the extensors a min. force of 10N with 1Hz and 50 cycles was applied. Each specimen was run 10 load levels with in the end 500cycles increasing stepwise up to 100N.
Results: A pretest on sawbones with shoestrings and anchors n=4 each side was performed.
A max load for the SR of 447N and for the DR of 767N could be measured (p<0.001).
The stiffness was for the SR 31N/mm, DR 55N/mm (p<0,001).
For the human cadaver test three groups with n=6 each showed in mean for the max. load in the native test set 1310N (flexor) and 1079N (extensor), in the SR 204N (flexor) and 214N (extensor), in the DR 318N (flexor) and 384N (extensor).
A significant difference could be found between flexor SR and DR (p =0.013) and extensor SR and DR (p=0,01). No significant difference between the flexor and extensor side could be seen.
The results for stiffness were in the native groupe 131N/mm (flexor), 130N/mm (extensor), SR 69N/mm (flexor), 68N/mm (extensor), DR 82N/mm (flexor), 70N/mm (extensor). No significant difference was between flexor and extensor side and between SR and DR.
Conclusion: There is less stability with a SR fixation. The SR failure was due to tendon tearing, the DR failure was due to anchore pull out. In DR fixation less tendon tearing appeared and higher loads to failure could be seen. Due to these results a DR technique is recommended.
