Biomechanical Evaluations of the Arthroscopic Rotator Cuff Repair Complex after Simulated Acute Injury (SS‐26)

PurposeTo evaluate the biomechanical properties of arthroscopic rotator cuff repair (suture anchors: single and double row) after a simulated acute injury.MethodsFresh-frozen human cadaveric shoulders (n=22) were dissected down to the humerus and rotator cuff tendon and mounted to a materials testing machine. One hundred cycles of cyclic tensile loading (20-100N) were performed on the rotator cuff complex after injury (3cm) and arthroscopically repaired with a single or double row suture anchor repair. The footprint restoration was recorded and a load-to-failure protocol was performed at a speed of 1.25 mm/sec. Four arthroscopic repairs tested were; Single Row A (Simple Lateral), Single Row B (Simple Mattress), Double Row A (Medial Mattress/Lateral Simple) and Double Row B (Transosseous Simple). The biomechanical properties were determined from the load-displacement curves.ResultsThe average footprint restoration of the single row repairs was 40% and significantly increased to 90% for the double row repairs (Figure 1, p<0.05). During failure of the repaired tendon, no significant differences could be detected between any of the repairs for the ultimate load (724±344N, 879±247N, 741±339N and 896±229N) and stiffness (100±43N/mm, 106±31N/mm, 89±34N/mm and 100±14N/mm), respectively (p>0.05). All specimens failed at the tendon-suture interface.ConclusionThe addition of another row of suture anchors significantly increases the footprint restoration; however does not increase the biomechanics of the rotator cuff complex after a simulated acute injury. With a minimal amount of cyclic loading (acute) after injury, the relatively healthy state of surrounding tissue after injury could play a big factor in the properties of the overall rotator cuff complex. These findings suggest that acute injuries to rotator cuff complex can be repaired with a single row of anchors without compromising the initial strength of the overall repair; however, the effect of increased footprint restoration of the double row combined with healing on the biomechanics of the rotator cuff complex must be investigated. PurposeTo evaluate the biomechanical properties of arthroscopic rotator cuff repair (suture anchors: single and double row) after a simulated acute injury. To evaluate the biomechanical properties of arthroscopic rotator cuff repair (suture anchors: single and double row) after a simulated acute injury. MethodsFresh-frozen human cadaveric shoulders (n=22) were dissected down to the humerus and rotator cuff tendon and mounted to a materials testing machine. One hundred cycles of cyclic tensile loading (20-100N) were performed on the rotator cuff complex after injury (3cm) and arthroscopically repaired with a single or double row suture anchor repair. The footprint restoration was recorded and a load-to-failure protocol was performed at a speed of 1.25 mm/sec. Four arthroscopic repairs tested were; Single Row A (Simple Lateral), Single Row B (Simple Mattress), Double Row A (Medial Mattress/Lateral Simple) and Double Row B (Transosseous Simple). The biomechanical properties were determined from the load-displacement curves. Fresh-frozen human cadaveric shoulders (n=22) were dissected down to the humerus and rotator cuff tendon and mounted to a materials testing machine. One hundred cycles of cyclic tensile loading (20-100N) were performed on the rotator cuff complex after injury (3cm) and arthroscopically repaired with a single or double row suture anchor repair. The footprint restoration was recorded and a load-to-failure protocol was performed at a speed of 1.25 mm/sec. Four arthroscopic repairs tested were; Single Row A (Simple Lateral), Single Row B (Simple Mattress), Double Row A (Medial Mattress/Lateral Simple) and Double Row B (Transosseous Simple). The biomechanical properties were determined from the load-displacement curves. ResultsThe average footprint restoration of the single row repairs was 40% and significantly increased to 90% for the double row repairs (Figure 1, p<0.05). During failure of the repaired tendon, no significant differences could be detected between any of the repairs for the ultimate load (724±344N, 879±247N, 741±339N and 896±229N) and stiffness (100±43N/mm, 106±31N/mm, 89±34N/mm and 100±14N/mm), respectively (p>0.05). All specimens failed at the tendon-suture interface. The average footprint restoration of the single row repairs was 40% and significantly increased to 90% for the double row repairs (Figure 1, p<0.05). During failure of the repaired tendon, no significant differences could be detected between any of the repairs for the ultimate load (724±344N, 879±247N, 741±339N and 896±229N) and stiffness (100±43N/mm, 106±31N/mm, 89±34N/mm and 100±14N/mm), respectively (p>0.05). All specimens failed at the tendon-suture interface. ConclusionThe addition of another row of suture anchors significantly increases the footprint restoration; however does not increase the biomechanics of the rotator cuff complex after a simulated acute injury. With a minimal amount of cyclic loading (acute) after injury, the relatively healthy state of surrounding tissue after injury could play a big factor in the properties of the overall rotator cuff complex. These findings suggest that acute injuries to rotator cuff complex can be repaired with a single row of anchors without compromising the initial strength of the overall repair; however, the effect of increased footprint restoration of the double row combined with healing on the biomechanics of the rotator cuff complex must be investigated. The addition of another row of suture anchors significantly increases the footprint restoration; however does not increase the biomechanics of the rotator cuff complex after a simulated acute injury. With a minimal amount of cyclic loading (acute) after injury, the relatively healthy state of surrounding tissue after injury could play a big factor in the properties of the overall rotator cuff complex. These findings suggest that acute injuries to rotator cuff complex can be repaired with a single row of anchors without compromising the initial strength of the overall repair; however, the effect of increased footprint restoration of the double row combined with healing on the biomechanics of the rotator cuff complex must be investigated.