Biomechanical study: determining the optimum insertion angle for screw-in suture anchors-is deadman's angle correct?

Area of Science:

• Orthopedic biomechanics
• Surgical implantology
• Materials science

Background:

• Suture anchors are critical for soft tissue reattachment in orthopedic surgery.
• The biomechanical performance of screw-in suture anchors can be influenced by insertion and loading parameters.
• Understanding these parameters is essential for optimizing surgical outcomes.

Purpose of the Study:

• To evaluate how insertion angle and load application angle affect the pullout strength of screw-in suture anchors.
• To determine the optimal configuration for maximizing anchor fixation.

Main Methods:

• Screw-in metallic suture anchors were tested in synthetic bone blocks.
• Anchors were inserted at various angles (30°, 45°, 60°, 90°).
• Pullout strength was measured using a tensile testing machine with varied suture pull angles.

Main Results:

• Maximum pullout strength (306 N) occurred when the anchor was inserted and pulled at 90°.
• Minimum pullout strength (97 N) was observed with a 30° insertion and 120° pull angle.
• Pullout strength was significantly greater when the pull angle matched the insertion angle (P < .0001).

Conclusions:

• Both insertion angle and load application angle significantly impact screw-in suture anchor pullout strength.
• Aligning the suture anchor's insertion angle with the direction of the applied load is crucial for achieving optimal biomechanical fixation.