ISAKOS Congress 2021

2021 ISAKOS Biennial Congress Paper


Biomechanical Comparison of a Novel, Multi-Planar Perpendicular Whipstitch with the Krackow Stitch And Standard Whipstitch

Stefano Muscatelli, MD, FAOA, FAAOS, Ann Arbor, Michigan UNITED STATES
Kempland C Walley, MD, Ann Arbor, Michigan UNITED STATES
Conor S. Daly-Seiler, Prof, Ann Arbor, MI UNITED STATES
Joseph A Greenstein, BS, Ann Arbor , Michigan UNITED STATES
Aaron David Sciascia, PhD, ATC, PES, SMTC, Richmond, KY UNITED STATES
David P Patterson, MD, Ann Arbor, MI UNITED STATES
Michael T. Freehill, MD, FAOA, FAAOS, Redwood City, CA UNITED STATES

University of Michigan, Ann Arbor, Michigan, UNITED STATES

FDA Status Not Applicable


The Krackow stitch is the superior technique for maximizing strength, while minimizing suture pull through, construct elongation, or graft compression.



Soft tissue repair and reconstruction commonly utilize the Krackow stitch and commercially designed whipstitch techniques, and both have been biomechanically evaluated. Perpendicular multi-planar fixation may improve the biomechanical properties compared to the commonly used techniques, as has been demonstrated with fracture fixation. The purpose of this study was to compare the elongation, yield load, ultimate failure, stiffness, and mode of failure of the traditional Krackow stitch, whipstitch, and a multi-planar perpendicular whipstitch. The hypothesis was that the multi-planar technique would demonstrate superior biomechanical properties over the standard techniques.

Materials And Methods

Thirty tibialis anterior cadaveric tendons were randomly assigned into 3 groups of 10. Three suturing techniques: the Krackow stitch (KS), standard commercial non-locking whipstitch (WS), and a novel, multi-planar perpendicular whipstitch (MP) were performed. The MP stitch was performed with orthogonal throws starting right to left, front to back, left to right, and back to front. Each technique used 4 passes of Number 2 FiberWire spaced 5mm apart and ending 10mm from the end of the tendon. Tendons were secured to a custom clamp and the other end sutured. Tendons were pre-loaded to 5N, pre-tensioned to 50N at 100mm/min for 3 cycles, returned to 5N for 1 minute, cycled from 5N to 100N at 200mm/min for 100 cycles, and then loaded to failure at 20mm/min. Elongation measurements were recorded after pre-tensioning and cycling, and recorded across the suture-tendon interface as well as from the base of the suture-tendon interface to markings on the suture limbs (total construct elongation). One-way analyses of variance were performed, with Bonferroni post hoc analysis when appropriate.


There were no differences in cross-sectional area or stiffness among the 3 groups (p>.05). The ultimate load for WS (183.33±57.44N) was significantly less compared to both MP (270.76±39.36N) and KS (298.90±25.94N) (p=.001). All 3 techniques were noted to have a decrease in tendon length at the suture-tendon interface during testing, termed compression. There was significantly more compression at the suture-tendon interface for WS compared to KS (p=.006). There was significantly less total construct elongation for KS compared to WS and MP for total displacement measured from pre-tensioning to the end of cycling (p<.001).


Based on these results, the Krackow stitch is the superior technique for maximizing strength, while minimizing suture pull through, construct elongation, or graft compression. If using the whipstitch for ease of use, the multi-planar perpendicular technique offers improved biomechanical properties over the standard whipstitch technique.

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