Comparison of Revision and Redislocation Rates After First-Time Anterior Shoulder Instability Between Subluxators and Dislocators: A Midterm Outcome Study

Ehab M Nazzal; Zachary J Herman; Ian D Engler; Janina Kaarre; Robert T Tisherman; Christopher M Gibbs; Justin J Greiner; Ajinkya Rai; Jonathan D Hughes; Bryson P Lesniak; Albert Lin

doi:10.1177/23259671241298014

Comparison of Revision and Redislocation Rates After First-Time Anterior Shoulder Instability Between Subluxators and Dislocators: A Midterm Outcome Study

Orthop J Sports Med. 2024 Dec 11;12(12):23259671241298014. doi: 10.1177/23259671241298014. eCollection 2024 Dec.

Authors

Affiliations

¹ Department of Orthopaedic Surgery, UPMC Freddie Fu Sports Medicine Center, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
² Central Maine Healthcare Orthopedics, Central Maine Medical Center, Lewiston, Maine, USA.
³ Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
⁴ Department of Orthopaedic Surgery, Duke University, Durham, North Carolina, USA.
⁵ University of Nebraska Medical Center, Omaha, Nebraska, USA.

Abstract

Background: Anterior shoulder instability is a common pathology seen especially in young men and highly active patient populations. Subluxation is a commonly encountered clinical issue, yet little is known about the effects of first-time subluxation compared with dislocation on shoulder stability and clinical outcomes after surgical stabilization.

Purpose: To compare revision and redislocation rates as well as patient-reported outcomes (PROs) between subluxators and dislocators after a first-time anterior shoulder instability event.

Study design: Cohort study; Level of evidence, 3.

Methods: Included were patients who underwent operative intervention for a first-time anterior instability event between 2013 and 2020 at a single institution. Exclusion criteria were posterior/multidirectional instability, revision surgery, and recurrent instability. The main outcomes of interest were the rates of redislocation and revision. Demographics and surgical details were retrospectively collected. Instability was categorized as subluxation (no documentation of formal shoulder reduction) or dislocation (documented formal shoulder reduction). Labral tear location and size were determined from preoperative magnetic resonance imaging scans. PROs and return-to-sport, redislocation, and revision rates were collected from prospective survey data.

Results: A total of 256 patients (141 subluxators and 115 dislocators) were available for analysis. There were no significant differences in baseline demographics or preoperative physical examination findings. Rates of bony Bankart lesions were comparable, but Hill-Sachs lesions were more commonly present in dislocators compared with subluxators (88.7% vs 53.9%; P < .01). There were no group differences in labral tear size, incidence of concomitant posterior or superior labrum anterior-posterior tears, or number of anchors used. Rates of remplissage were comparable between groups. Prospectively collected survey data of 60 patients (35 subluxators, 25 dislocators) were collected at 6.4 and 7.1 years of follow-up, respectively. Rates of recurrent dislocation (11.8% vs 20.0%) and revision (8.8% vs 16.0%) were comparable between subluxators and dislocators, respectively. All PROs and return-to-sport rates were comparable between groups.

Conclusion: Subluxators and dislocators may present with comparable rates of redislocation and revision surgery even at midterm follow-up. Both cohorts may further present with comparable injury characteristics and PROs. Given the findings, future prospective studies comparing outcomes of first-time instability events are needed.

Keywords: anterior shoulder instability; dislocation; outcomes; shoulder; subluxation.