Flexor tendon repair with a knotless, bidirectional barbed suture: an in vivo biomechanical analysis.
OBJECTIVE
To compare and analyze biomechanical properties and histological characteristics of flexor tendons either repaired by a 4-strand modified Kessler technique or using barbed suture with a knotless repair technique in an in vivo model.


METHODS
A total of 25 chickens underwent surgical transection of the flexor digitorum profundus tendon followed by either a 4-strand Kessler repair or a knotless repair with barbed suture. Chickens were randomly assigned to 1 of 3 groups with various postoperative times to death. Harvested tendons were subjected to biomechanical testing or histologic analysis.


RESULTS
Harvested tendons revealed failures in 25% of knotless repairs (8 of 32) and 8% of 4-strand Kessler repairs (2 of 24). Biomechanical testing revealed no significant difference in tensile strength between 4-strand Kessler and barbed repairs; however, this lack of difference may be attributed to lower statistical power. We noted a trend toward a gradual decrease in strength over time for barbed repairs, whereas we noticed the opposite for the 4-strand Kessler repairs. Mode of failure during testing differed between repair types. The barbed repairs tended toward suture breakage as opposed to 4-strand Kessler repairs, which demonstrated suture pullout. Histological analysis identified no difference in the degree of inflammation or fibrosis; however, there was a vigorous foreign body reaction around the 4-strand Kessler repair and no such response around the barbed repairs.


CONCLUSIONS
In this model, knotless barbed repairs trended toward higher in vivo failure rates and biomechanical inferiority under physiologic conditions, with each repair technique differing in mode of failure and respective histologic reaction. We are unable to recommend the use of knotless barbed repair over the 4-strand modified Kessler technique.


CONCLUSIONS
For the repair techniques tested, surgeons should prefer standard Kessler repairs over the described knotless technique with barbed suture.
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL. Electronic address: grady.maddox@gmail.com.
Grady E
GE
Maddox
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Jonathan
J
Ludwig
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Eric R
ER
Craig
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
David
D
Woods
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Aaron
A
Joiner
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Nilesh
N
Chaudhari
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Cheryl
C
Killingsworth
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Gene P
GP
Siegal
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Alan
A
Eberhardt
Division of Orthopaedic Surgery, University of Alabama at Birmingham, Birmingham, AL.
Brent
B
Ponce
D000818:Animals; D001696:Biomechanical Phenomena; D002645:Chickens; D019651:Plastic Surgery Procedures / Q000379:methods*; D013536:Suture Techniques; D013537:Sutures; D013708:Tendon Injuries / Q000601:surgery*; D013718:Tensile Strength
Barbed suture; flexor tendon repair; knotless repair