Suturing the myotendinous junction in total hip arthroplasty: A biomechanical comparison of different stitching techniques

• A new stitching technique for myotendinous junction is proposed.
• The new stitch is asymmetrical and uses multiple fixation points on the muscle side.
• The new stitch may improve fixation strength of the repaired junction up to 40%.
• The new stitch does not alter the stiffness of repair.

BackgroundThe repair of the myotendinous junction following total hip arthroplasty is challenging as this region is the weakest part of the muscle structure. This study investigated the mechanical behaviour and the mode of failure of different suturing techniques of the myotendinous junction. A new asymmetrical stitch was compared to two widely used techniques, i.e. the simple stitch (two loops in parallel) and the figure-of-eight stitch.MethodsThe ovine triceps brachii myotendinous junction was selected as the experimental model. Each technique was sewn in muscle belly on one side and in a polyester belt (no-tendon configuration) or in thin tendon (full configuration) on the other side. The former was chosen to determine the grasping power of the stitch on the muscle despite the tendon quality, the latter to simulate a very thin gluteus medius tendon.FindingsThe new stitch showed a higher ultimate strength (+ 40%) compared to the two controls in the no-tendon configuration. In the full configuration, no significant increase was observed, although failure of the new stitch always occurred at the tendon side. Furthermore, the new stitch does not alter the stiffness of repair.InterpretationThe new stitch has a higher grasping power on muscle belly than the single passing-through stitches thanks to the multiple fixation points, which better distribute the load in the tissue. However, such performance can be fully exploited only in the presence of good quality tendons.