Screw Fixation has Better Outcomes, Lower Incidence of Re-dislocation and Lower Bone Resorption than Button Fixation for Arthroscopic Anatomic Glenoid Reconstruction with Distal Tibia Allograft: A Matched Cohort Analysis.

Abstract

Purpose: To compare the clinical outcomes between patients who received arthroscopic anatomic glenoid reconstruction (AAGR) using distal tibia allograft with button fixation versus screw fixation.

Methods: A retrospective chart review was conducted for all patients who underwent AAGR with button or screw fixation between 2012 and 2021. Patients were matched at a 1:1 ratio based on sex, type of surgery, and time since surgery. All patients who were included had a minimum clinical follow-up of two years. Study outcomes compared Western Ontario Shoulder Instability (WOSI) Index scores, recurrence of instability, incidence of revision surgeries, and CT readings.

Results: 44 patients were included with 22 patients in each group. The pre-operative glenoid bone loss was 22.57 ± 8.06% in the screw group and 22.92 ± 8.84% in the button group (p = 0.898). Both groups demonstrated a significant improvement in WOSI from pre-operative to latest follow-up, however patients in the screw group demonstrated significantly better WOSI scores at both two-year (p = 0.003) and latest follow-up (p = 0.019) compared to the button group. Recurrent dislocation was observed in 9 patients (40.9%), all of whom underwent button fixation (p < 0.001). Two patients in the screw group experienced hardware complications (p = 0.488). Individuals who underwent button fixation were significantly more likely to undergo a revision surgery for recurrent instability (p = 0.011). Individuals in the button group demonstrated a significantly smaller mean graft AP diameter postoperatively (p < 0.001).

Conclusion: AAGR with both screw fixation results in significantly improved WOSI scores at minimum two-year follow-up. Button fixation has a significantly higher incidence of re-dislocation. Radiographic findings suggest that on average, button fixation results in higher grade bone resorption and subsequently smaller post-operative glenoid AP width than screw fixation.

Level of evidence: Level III, retrospective comparative case series.