Footprint Contact Area and Interface Pressure Comparison Between the Knotless and Knot-Tying Transosseous-Equivalent Technique for Rotator Cuff Repair

To quantify and compare the footprint contact area and interface pressure on the greater tuberosity between knotless and knot-tying transosseous-equivalent (TOE) repair using pressure-sensitive film. Methods: We used 11 pairs of fresh-frozen cadaveric shoulders (22 specimens), in which rotator cuff tears were created before repair. Each pair was randomized to either conventional medial knot-tying TOE repair (group A) or medial knotless TOE repair using the modified Mason-Allen technique (group B). Pressure-sensitive film was used to quantify the pressurized contact area and interface pressure between the greater tuberosity and supraspinatus tendon. Results: The mean pressurized contact area was 33.2 +/- 2.5 mm(2) for group A and 28.4 +/- 2.4 mm(2) for group B. There was a significant difference between groups (P = .005). Although the overall contact configuration of both groups was similar and showed an M shape, group A showed a greater pressurized configuration around the medial row. The mean interface pressure was 0.20 +/- 0.02 MPa for group A and 0.17 +/- 0.02 MPa for group B. There was a significant difference between groups (P = .001). Conclusions: Contrary to our hypothesis, in this time-zero study, medial knotless TOE repair using a modified MasonAllen suture produced a significantly inferior footprint contact area and interface pressure compared with conventional medial knot-tying TOE repair.