2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


"Distance to Dislocation" is More Valid than "Hill-sachs to Glenoid Track Width Ratio" to Predict the Risk of Recurrent Instability after Arthroscopic Bankart Repair

Mac Donald Tedah Djemetio, MD, Brescia ITALY
Andrea Pratobevera, MD, Carate Brianza, Lombardia ITALY
Andrea Bergomi, MD, Brescia ITALY
Marco Adriani, MD, Brescia, Brescia ITALY
Maristella Francesca Saccomanno, MD, PhD, Brescia ITALY
Giuseppe Milano, Prof., Brescia, BS ITALY

University of Brescia, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Brescia, Lombardy, ITALY

FDA Status Not Applicable

Summary

This study found that both the Hill-Sachs to glenoid track width ratio (H/G ratio) and distance to dislocation (DTD) are reliable predictors of arthroscopic Bankart repair failure, with DTD being significantly associated with a higher risk of recurrence in patients with on-track bipolar bone defects.

Abstract

Purpose

To assess the reliability of the Hill-Sachs to glenoid track width ratio (H/G ratio) and distance to dislocation (DTD) and their correlation and to compare their diagnostic accuracy (DA) in predicting the risk of recurrence in patients with on-track bipolar bone defect (BBDs) who had undergone an arthroscopic Bankart repair (ABR).

Methods

A retrospective study was conducted on patients affected by recurrent anterior glenohumeral instability with an on-track BBD who underwent ABR alone. The Hill-Sachs interval (HSI) and glenoid bone defect (GBD) were measured using 3D reconstructions of preoperative CT scans; based on those measures, the H/G ratio and DTD were calculated. Clinical outcomes were assessed using the WOSI score, ASES score, and Tegner Activity Scale. Interobserver reliability was tested for the H/G ratio and DTD. The primary outcome was the correlation between the H/G ratio and DTD; the secondary outcomes were the predictive values of the two measures for the recurrence rate and PROMs. Significant was set at p<0.05.

Results

The study included 80 patients. H/G ratio and DTD demonstrated substantial interobserver reliability and a significant negative correlation (ρ = -0.986, p < 0.0001). The overall recurrence rate was 12.5% (10 cases). Comparison between recurrence and non-recurrence groups showed significant differences for both H/G ratio (0.79 + 0.2 and 0.63 + 0.18, respectively; p=0.014) and DTD (0.43 + 0.40 and 0.79 + 0.41, respectively; p=0.008). There was no significant correlation between both measures and PROMs. The recurrence rate was greater than 20% when the H/G ratio and DTD exceeded the critical thresholds (> 0.7 and < 8mm for the H/G ratio and DTD, respectively). However, only the dichotomic DTD measure was significantly associated with the recurrence rate. Multivariate analysis indicated that only DTD was independently associated with the risk of recurrence. Analysis of DA showed no significant differences between the two measures, albeit DTD had higher sensitivity (90%) than H/G ratio (70%).

Conclusion

The H/G ratio and DTD have substantial interobserver reliability and have a strong negative correlation. Both measures are significantly associated with the occurrence of ABR failure in patients affected by on-track BBDs. Estimated optimal cutoff values for H/G ratio (> 0.7) and DTD (< 8mm) showed no significant differences in DA, but only DTD was significantly associated with the risk of recurrence.

Level of evidence: Retrospective cohort study, level III

Keywords: recurrent instability, arthroscopic Bankart repair, bipolar bone defects, on-track/off-track, H/G ratio, near-track lesion