2015 ISAKOS Biennial Congress ePoster #2207

Biomechanical Evaluation of Long Head of Biceps Tenodesis with Knotless Screw and Interference Screw Techniques

Wei-Ren Su, MD, MSc, Tainan TAIWAN
Chih-Hsun Chang, MD, Tainan TAIWAN
Chih-Kai Hong, MD, Tainan TAIWAN
I-Ming Jou, MD, PhD, Tainan TAIWAN

National Cheng Kung University Hospital , Tainan, TAIWAN

FDA Status Not Applicable

Summary: Biceps tenodesis with knotless screw may allow for the avoidance of arthroscopic knot tying but is biomechanically inferior to tenodesis with interference screw.

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Abstract:

Purpose

The purpose of this study was to biomechanically evaluate a new technique of knotless screw fixation for suprapectoral biceps tenodesis and to compare it with the interference screw technique.

Methods

Twenty-four fresh-frozen human cadaveric shoulders with a mean age of 63.3±8 years were studied. The specimens were randomly divided into 3 experimental biceps tenodesis groups (n=8): single knotless screw, double knotless screw and interference screw. Each tenodesis specimen was mounted on a mechanical testing machine, preloaded for 2 minutes at 5 N, and followed by an axial load to failure test (1 mm/s). We evaluated the mode of failure and computed the ultimate failure load, and stiffness.

Results

The interference screw technique had the highest ultimate failure load (215.8±43.1 N), significantly higher than that for the single (70.1±13.6 N) and double (148.8±13.1 N) knotless screw groups (P < .0001). In addition, the interference screw technique had the greatest stiffness (25.7±5.2 N/mm), significantly higher than that for the single (7.1±1.5 N/mm) and double (11.9±1.9 N/mm) knotless screw groups (P < .0001). The double knotless screw group had the second greatest ultimate failure load and stiffness, significantly greater than that with the single knotless screw technique (P < .0001 and P = 0.024, respectively). The most common mode of failure was suture slippage for both the single (6/8) and double knotless screw (7/8) techniques and biceps tendon tearing for the interference screw techniques (6/8)

Conclusions

In this biomechanical study, double knotless screw fixation was found to have a significantly lesser ultimate failure load and stiffness than the interference screw fixation but a greater value than the single knotless screw fixation.