Fatigue properties of suture anchors in anterior shoulder reconstructions: Mitek GII

The American Society of Shoulder and Elbow Therapists' Consensus Rehabilitation Guideline for Arthroscopic Anterior Capsulolabral Repair of the Shoulder

“…32,92 Light strengthening and active ROM within the staged ROM goals would not likely result in excessive loading; however, in our opinion, it sends an inconsistent message to the patient during this early postoperative period that some strengthening is approved yet significant restrictions of activities of daily living and immobilization are necessary. We believe this inconsistency can lead to excessive arm use, in terms of both loading and ROM, resulting in too much stress to the surgical repair.…”

“…19,35 A gradual increase in applied stress, in a process analogous to Wollf 's law of bone healing, 96 results in enhanced structural integrity of the capsulolabral complex as additional collagen fibers are laid down in response to controlled stresses. However, it is equally important to understand that with excessive stress to the capsulolabral complex, either in terms of magnitude or timing, the tissues will be unable to adequately adapt, 32,92 and damage will result to either the healing tissues or the suture anchors. During rehabilitation, there are 3 mechanisms by which rehabilitation providers apply stress to the surgical repair to positively affect patient outcome: (1) absolute ROM, (2) controlled submaximal tissue loading, and (3) dynamic stabilization.…”

“…30,68,81,86 Much in the same way micromotion prevents bony union during fracture healing, submaximal tissue loading also has the potential to disrupt the tenuous tissue healing bonds between the labrum and bone and between the plicated layers of the capsule. 32,92 Repeated submaximal stress of a ligament plication in an animal model has been shown to negatively affect mechanical resistance properties, even as late as postoperative week 12.…”

“…Potentially injurious forces can be avoided by slowly progressing through staged ROM goals, controlling submaximal loading forces by limiting repetitive activity of the arm, and avoiding forces that may overstress the structural integrity of the capsulolabral repair by not lifting heavy objects. Wetzler et al 92 estimated that a shoulder would typically experience 1000 to 2000 loading cycles during the first 6 weeks of rehabilitation following capsulolabral repair. Based upon their analysis, the maximum load any particular suture anchor could accommodate is 60 to 100 N, based upon the location of the suture anchors, with lower forces to failure on the more inferior portions of the glenoid.…”

“…Still, we believe these findings provide some support for minimizing the number and amount of repetitive loads, particularly during the first phase of rehabilitation. 92 Because the rotator cuff muscles are not detached during arthroscopic stabilization, both passive and/or active assistive ROM exercises are appropriate in the early stages of postoperative rehabilitation. Therefore, unlike rehabilitation of the patient following rotator cuff repair, active assistive exercises can be performed immediately for the patient following arthroscopic capsulolabral repair.…”