Background: The suture configurations in arthroscopic rotator cuff
repairs have been limited to simple and horizontal stitches. Recent objective
evaluations have demonstrated high failure rates of arthroscopic repairs of
rotator cuff tears. A novel stitch for arthroscopic repair of the rotator
cuff, the massive cuff stitch, was developed to increase the strength of the
suture-tendon interface. The goal of this study was to determine the
biomechanical properties of the massive cuff stitch and to compare it with
other stitches commonly used for rotator cuff repair.
Methods: Eight pairs of sheep infraspinatus tendons were harvested
and split in half to yield a set of four tendon specimens from each animal.
Four stitch configurations (simple, horizontal, massive cuff, and modified
Mason-Allen) were randomized and biomechanically tested in each set of tendon
specimens. Each specimen was first cyclically loaded on an MTS uniaxial load
frame under force control from 5 to 30 N at 0.25 Hz for twenty cycles. Each
specimen was then loaded to failure under displacement control at a rate of 1
mm/sec. Cyclic elongation, peak-to-peak displacement, ultimate tensile load,
and stiffness were measured with use of an optical motion analysis system and
load-cell output. The type of failure (suture breakage or pull-out) was also
recorded. A repeated-measures analysis of variance was performed on the
results, with the alpha level of significance set at p < 0.05.
Results: There was no difference in cyclic elongation or
peak-to-peak displacement among the four stitches. Ultimate tensile load was
significantly higher (p < 0.05) for the massive cuff stitch (233 ±
40 N) and the modified Mason-Allen stitch (246 ± 40 N) than it was for
either the simple stitch (72 ± 18 N) or the horizontal stitch (77
± 15 N). There was no significant difference in the ultimate load
between the massive cuff and modified Mason-Allen stitches. There was also no
difference in stiffness among the four stitches. The simple and horizontal
stitches failed by tissue pull-out, whereas the massive cuff and Mason-Allen
stitches failed by a mixture of suture breakage and pull-out.
Conclusions: The massive cuff stitch provides strength comparable
with that of the modified Mason-Allen stitch commonly used in open rotator
cuff repair. The ultimate tensile load before failure of the massive cuff
stitch was significantly higher (p < 0.05) than that of the simple and
Clinical Relevance: The massive cuff stitch may be a promising
alternative for arthroscopic repairs of rotator cuff tendons.