Superior biomechanical properties and tying time with the modified Prusik knot and Wittstein suture loop to the Krackow stitch
The purposes of the study were to compare (1) the biomechanical properties of the modified Prusik knot, Wittstein suture loop, and Krackow stitch fixation, and (2) the knot tying times for tendon graft fixation among the Krackow stitch, modified rolling hitch, modified Prusik knot, and Wittstein suture loop.
Materials and methods
First, 33 fresh-frozen porcine flexor profundus tendons were randomly divided into three groups of 11 specimens. The experimental procedure was designed to assess elongation of the suture-tendon construct across the modified Prusik knot, Wittstein suture loop, and the Krackow stitch. Multistranded nonabsorbable sutures were used. Each specimen was pre-tensioned to 100 N for three cycles, cyclically loaded to 200 N for 200 cycles, and finally loaded to failure. Elongation, load to failure, and failure mode of each specimen were recorded. Second, the knot tying times for modified rolling hitch, modified Prusik knot, Wittstein suture loop, and Krackow stitch were investigated. The measurements were taken on three different occasions to account for intraobserver repeatability and interobserver reproducibility.
The elongation after cyclic loading of the modified Prusik knot (22 ± 6%), Wittstein suture loop (25 ± 2%) were significantly smaller than the Krackow stitch (31 ± 5%) (p = 0.001 and 0.003, respectively). The failure loads of three groups were not significantly from one another. Meanwhile, the Krackow stitch group (80.9 ± 16.7 s) had significantly longer average procedure time than the modified rolling hitch group (9.2. ± 1.9 s) (p < 0.001), modified Prusik knot group (9.1 ± 1.8 s) (p < 0.001), and Wittstein suture loop group (9.0 ± 2.2 s) (p < 0.001).
Compared to the Krackow stitch, the modified Prusik knot and Wittstein suture loop had less elongation after cyclic loading and similar ultimate load to failure in this porcine in vitro biomechanical study. Shorter knot tying times were required to complete the modified rolling hitch, modified Prusik knot, and Wittstein suture loop than the Krackow stitch.
KeywordsModified Prusik knot Wittstein suture loop Krackow stitch Ligament reconstruction Modified rolling hitch Knot tying time
We thank Shing-Yun Chang BS, MSc (Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan) and Ting-Hsuan Kuo (Department of Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan) for assistance with this project.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
There is no funding source.
This article does not contain any studies with human participants or animals performed by any of the authors.
- 11.Krappinger D, Kralinger FS, El Attal R, Hackl W, Haid C (2007) Modified Prusik knot versus whipstitch technique for soft tissue fixation in anterior cruciate ligament reconstruction: a biomechanical analysis. Knee Surg Sports Traumatol Arthrosc 15(4):418–423. doi: 10.1007/s00167-006-0176-9 CrossRefPubMedGoogle Scholar
- 22.Domnick C, Wieskotter B, Raschke MJ, Schulze M, Kronenberg D, Wefelmeier M, Langer MF, Herbort M (2016) Evaluation of biomechanical properties: are porcine flexor tendons and bovine extensor tendons eligible surrogates for human tendons in in vitro studies? Arch Orthop Trauma Surg 136(10):1465–1471. doi: 10.1007/s00402-016-2529-2 CrossRefPubMedGoogle Scholar