Abstract:Purpose To evaluate the biomechanical properties of ultimate pulling strength of the suture anchors,based on the arthroscopic rotator cuff repair (RCR) surgery, the angle of humerus implantation using suture anchor (SA) is considered.Methods Polyurethane materials with densities of 0.16g/cm3 and 0.32g/cm3 were used to simulate osteoporosis and normal cancellous bone, and polyurethane materials with densities of 0.64g/cm3 and 3mm thick were used to simulate human cortical bone. The two kinds of cancellous bone models were adhered together with cortical bone model to construct human humerus model.Using of titanium metal suture anchor were inserted at 45 °, 60 °, 75 ° and 90 ° Angle into humerus model, then carries on the continuous tensile experiment, and between the humerus model surface and suture anchor using 45 ° pulling direction to simulate the supraspinatus physiological traction direction,each group continuously for 8 times drawing test, record the pull out strength and failure mode.Results The pullout strength of high-density bone was significantly higher than that for low-density bone (P<0.001).In addition, under the same density, the pullout strength was bigger at the 90 ° than at the 45 °, 60 ° and 75 ° insertion angle (P < 0.01).Conclusion The metal suture anchor showed higher pulling strength and significant difference when it was applied to high-density models,Inserted at 90 ° angle into humerus model has better fixation strength, with the proposed by Burkhart "Deadman Theory" is a bit different, but the pull out strength of implantation of 45 ° angle was obviously higher than at 60 ° and 75 °, showed that 45°angle implanted still has certain advantages.meanwhile, the anchor vertically implantation is beneficia in the operation of tying knots and the recovery of supraspinatus tendon.Clinical Relevance The study provides biomechanical basis that the rotator cuff repair surgery anchor vertically implanted humerus is better than at the 45 ° angle.