Biomechanical characteristics of suture anchor implants for flexor digitorum profundus repair.
OBJECTIVE
To determine strength and failure characteristics of 2 suture anchors used to repair simulated flexor digitorum profundus avulsions during passive mobilization protocol simulation.


METHODS
We simulated avulsion of the flexor digitorum profundus tendon in 30 distal phalanges from fresh-frozen human cadavers. Repair was performed with a 1.3 × 3.7 mm Micro-Mitek suture anchor (3-0 Orthocord suture) and a 2.2 × 4.0-mm Corkscrew suture anchor (2-0 FiberWire suture). All specimens were loaded cyclically from 2 to 15 N at 5 N/s for a total of 500 cycles. Samples were tested to failure at the completion of 500 cycles. Load at failure, load at first noteworthy displacement (> 2 mm), elongation of the system, gap formation at the tendon-bone interface, and the mechanism of failure were assessed.


RESULTS
Suture failure at maximum load was the prevalent failure mechanism in both groups. No statistically significant difference in elongation of the tendon-suture complex was observed. The Corkscrew suture anchor showed a significantly superior performance in load to failure, load at first significant displacement, and gap formation at the tendon-bone interface.


CONCLUSIONS
The significantly higher load capacity at first displacement (> 2 mm) and the significance of a lower gap formation at the repair site seem to be the most relevant clinical parameters. Based on this concept, the Corkscrew anchor may be superior biomechanically to the Micro-Mitek when considering an early passive mobilization protocol.


CONCLUSIONS
The choice of an appropriate implant may influence the postoperative mobilization protocol and thereby improve currently reported success rates. Defining a biomechanically superior implant will provide an essential basis for further studies in flexor tendon repair research.
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria. Electronic address: gabriel.halat@meduniwien.ac.at.
Gabriel
G
Halát
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria.
Lukas
L
Negrin
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria.
Thomas
T
Koch
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria.
Jochen
J
Erhart
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria.
Patrick
P
Platzer
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria.
Stefan
S
Hajdu
University Clinic for Trauma Surgery and the Center for Anatomy and Cell Biology, Medical University Vienna; and the Institute of Materials Science and Technology, Faculty of Mechanical and Industrial Engineering, Vienna University of Technology, Vienna, Austria.
Johannes
J
Streicher
D004868:Equipment Failure; D005383:Finger Injuries / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D053441:Suture Anchors; D013708:Tendon Injuries / Q000601:surgery*; D013718:Tensile Strength; D016474:Weight-Bearing
Flexor digitorum profundus tendon avulsion; Jersey finger; flexor digitorum profundus tendon repair; suture anchor biomechanics; suture anchor design