Comparative testing by cyclic loading of rotator cuff suture anchors containing multiple high-strength sutures

Area of Science:

• Orthopedic surgery
• Biomechanical testing
• Shoulder arthroscopy

Background:

• Rotator cuff tears are common, often requiring surgical repair with anchors.
• Medial-row and lateral-row anchor placement are surgical techniques used for rotator cuff repair.
• Understanding anchor performance is crucial for optimizing surgical outcomes.

Purpose of the Study:

• To compare the biomechanical performance of isolated medial-row versus isolated lateral-row anchors.
• To evaluate anchor cyclic loading and destructive testing in a cadaveric model.
• To determine failure modes and load capacities of different anchor types.

Main Methods:

• 16 human cadaveric humeri were used for anchor testing.
• Four medial-row and four lateral-row anchors were tested in different humeral head locations.
• Constructs underwent cyclic loading (10-60 N at 1 Hz for 500 cycles) followed by destructive testing.

Main Results:

• Lateral-row anchors exhibited greater displacement (4.4 mm) than medial-row anchors (1.9 mm).
• Ultimate failure loads ranged from 163 N (Footprint) to 308 N (Versalok).
• The primary failure mode was anchor pullout, with lateral-row anchors failing at lower loads and earlier cycles.

Conclusions:

• Medial-row anchors provide superior fixation strength and security compared to lateral-row anchors.
• Lateral-row anchors demonstrate increased displacement and are more susceptible to early failure at the eyelet.
• Design differences contribute to the observed performance disparities between medial and lateral row anchors.