Multidirectional instability (MDI) of the shoulder is a clinical diagnosis that can be difficult to both diagnose and treat. There are many proposed classification systems for shoulder instability, such as the AMBRI (atraumatic, multidirectional, bilateral, rehabilitation, inferior capsular shift) and TUBS (traumatic, unilateral, Bankart, surgery) system and the FEDS (frequency, etiology [cause], direction, severity) system. Currently, the most universal definition of MDI is symptomatic instability of the shoulder joint in more than one direction, one of which is inferior. The hallmark of MDI is an inferior sulcus sign on a physical examination. The ‘‘classic’’ onset of MDI has been defined as atraumatic or trivial; however, MDI has also been observed in the context of traumatic injuries, especially in patients without hyperlaxity. Regarding the role of sex with MDI, more severe cases of MDI have previously been reported in female patients.
Historically, the treatment for MDI has been nonoperative with a supervised exercise program, but results have sometimes been suboptimal. The refinement of open capsular shift surgery and the development of arthroscopic techniques for restoring stability to the glenohumeral joint have allowed for surgical treatment in those who have failed nonoperative treatment. Most arthroscopic techniques have now evolved to include capsulorrhaphy with suture anchors, which effectively reduces the capsular joint volume to magnitudes equal to or better than that with open capsular shift, with the ability to also address both sides of the joint simultaneously. Initial outcome studies have shown promising results with arthroscopic capsulorrhaphy for the treatment of MDI. However, little is known about if and how sex and the onset of MDI affect intraoperative findings and midterm outcomes of arthroscopic pancapsular capsulorrhaphy (APC).
The purpose of this study was to compare intraoperative findings and midterm outcomes of APC with suture anchors for MDI between female and male athletes and between an atraumatic versus traumatic onset of MDI. We hypothesized that a traumatic onset of MDI would be associated with more concomitant glenohumeral injuries and better outcomes whereas outcomes would be less favorable for female than male patients.