Paper 01: Capsuloligamentous Laxity is a Risk Factor for Failure in Near Track Lesions Following Arthroscopic Anterior Shoulder Stabilization

Abstract

Objectives: Recurrent anterior shoulder instability after arthroscopic Bankart repair presents a challenging clinical problem, with the primary stabilization procedure often portending the best chance for clinical success. While the glenoid track concept continues to evolve, a limitation of the glenoid track is that it relies on bony anatomy without specific considerations for capsuloligamentous integrity or the effect that capsular laxity may have on the glenohumeral contact points throughout shoulder range of motion. The purpose of the study was to determine if capsuloligamentous laxity has a modifying effect on the glenoid track, specifically for on-track lesions with a small distance to dislocation (DTD) from being an off-track lesion or the so-called “near-track” lesion. This may explain why some on-track lesions are at an increased risk of recurrent instability. We hypothesized that patients with ligamentous laxity and “near track” lesions would be at increased risk of recurrent instability following arthroscopic Bankart repair. Methods: Consecutive patients with on-track Hill-Sachs lesions who underwent primary arthroscopic Bankart repair alone without remplissage for recurrent anterior glenohumeral instability between January 2007 and December 2015 at a single institution were retrospectively reviewed. Patients with less than 2-year follow up, glenoid bone loss > 20%, off-track lesions, concomitant remplissage, and atraumatic instability were excluded. Determination of shoulder laxity was based on exam under anesthesia (EUA), including anterior load and shift, posterior load and shift, and sulcus testing at the time of surgery before arthroscopy. Capsuloligamentous shoulder hyperlaxity was defined as external rotation of >85o and/or grade of 2+ or greater load and shift in two or more planes. Measurements of glenoid bone loss, Hill-Sachs interval (HSI), and glenoid track (GT) were performed based on prior described methods. DTD was calculated (DTD=GT-HSI, with DTD>0 classified as on-track lesions). Near track lesions were defined as 0<DTD<8mm. Failure was defined as recurrent dislocation. Results: A total of 173 patients were initially identified, of which 151 met inclusion criteria and were included for analysis. 72.8% of patients were males and mean age was 20.1 ± 5.7 years. Patients were divided into two groups based on shoulder laxity; group 1 consisted of 74 patients with hyperlaxity, and group 2 consisted of 77 patients without hyperlaxity. Overall, 21 patients (13.9%) sustained a recurrent dislocation and 35 patients (23.2%) had recurrent instability episodes. Failure was associated with glenoid bone loss (p<0.001 ), longer HS length ( p=0.007), occurrence of >1 instability episode preoperatively (p=0.018 ), and smaller DTD ( p=0.0008). Hyperlaxity was associated with the use of more anchors ( p=0.0001). Shoulder laxity was not independently predictive of overall failure (Figure 1, p=0.18); however, DTD was significantly associated with failure risk and recurrent instability in patients with hyperlaxity ( p=0.006) specifically in younger patients with hyperlaxity (Figure 1, Table 1). Conclusions: Our study suggests that while capsuloligamentous laxity is not independently predictive of failure after arthroscopic Bankart repair for on-track lesions, laxity may play a significant role in clinical outcomes in patients with a small DTD or near-track lesions. In younger patients with near-track lesions, hyperlaxity may be particularly predictive of failure after arthroscopic Bankart repair. As our understanding of the glenoid track continues to evolve, surgeons may need to consider the track concept as a continuum with evolving surgical algorithms other than an arthroscopic Bankart alone in young patients with near track lesions and hyperlaxity. [Table: see text]