Poster 158: Remplissage Reduces Recurrent Instability in High-Risk Patients with “On-Track” Hill-Sachs Lesions

Objectives: The objective of this study was to compare recurrent instability rates and patient reported outcomes (PROs) between patients with “on-track” Hill-Sachs lesions who underwent ALR alone versus patients who had received ALR with remplissage (ALR+R). Our hypothesis was that performing a remplissage in addition to ALR would decrease the recurrence rate, especially among high-risk subjects such as contact athletes. Methods: We performed a retrospective analysis of patients age 12-40 years old with “on-track” shoulders who underwent ALR+R between Jan 2014 and Dec 2019 at a single institution, with minimum 2-year follow-up. Exclusion criteria included: prior ipsilateral shoulder surgery, >20% glenoid bone loss (GBL), concomitant rotator cuff repair, and connective-tissue disorder. We then identified a cohort of patients meeting the same inclusion and exclusion criteria who had undergone ALR alone. Patient age, gender, follow-up time, first-time dislocation vs. multiple dislocations, and contact sport participation were recorded. GBL, Hills-Sachs Interval (HSI), glenoid track (GT), and DTD were measured from pre-operative MRIs. The patients were then contacted to determine if they had had recurrent instability and/or revision surgery. We also obtained current Western Ontario Shoulder Instability Index (WOSI) and Single Assessment Numeric Evaluation (SANE) scores. Subgroup analysis was performed on “high-risk” patients (DTD <10mm and contact sport participation) from each cohort. Results: The ALR+R cohort had 17 subjects and the ALR cohort had 51 subjects. There were no differences in demographic variables or GBL between cohorts (P>0.05). The ALR+R subjects had larger HSI (14.7mm ± 2.4 vs 5.7mm ± 5.0; P<0.001) and smaller DTD (8.2mm ± 3.2 vs 16.2mm ± 5.7; P<0.001). There were no difference in WOSI (304.2 ± 213 vs 302.4mm ± 344.2; P=0.98) or SANE (84.3 ± 16.6 vs 87.3 ± 8.9; P=0.94) scores between groups. Only 1 (5.9%) subject in the ALR+R cohort had a recurrent subluxation, and there were no dislocations or revision surgeries. The ALR cohort had 7 (13.7%) recurrent dislocations, 3 (5.8%) recurrent subluxations, and 6 (11.8%) revision surgeries. Multivariate analysis indicated that smaller DTD (OR 0.71; 95% CI (0.56 – 0.87); P=0.001) and contact sport participation (OR 8.67; 95% CI (1.19 – 63.35); P=0.033) were associated with increased risk of recurrent instability. After adjusting for contact sport participation and DTD value, the ALR+R cohort had a 98.8% lower risk of recurrent instability compared to the ALR cohort (OR 0.012; 95% CI (0.0001 – 0.22); P=0.003). Among “high risk” subjects, there was only 1 (11.1%) instability event in the ALR+R group and 4 (80%) in the ALR alone group (P=0.023) Conclusions: DTD calculations can be used as an independent predictor of recurrent shoulder dislocation following ALR for treatment of anterior shoulder instability. For patients with “on- track” shoulder lesions, but small DTD measurements (“near-track” lesions), remplissage is protective against recurrent instability events and need for revision surgery. This may be especially true for “high- risk” patients, such as those who participate in contact sports.