Acute Open Reduction and Internal Fixation versus Non-Operative Treatment of Scapular Spine Fractures after Reverse Shoulder Arthroplasty: A Propensity Score-Matched Study.

Abstract

Background: Scapular spine fractures occur in 1-11% of cases after reverse shoulder arthroplasty (RSA). While non-operative management has been recommended, poor clinical outcomes have been reported for Levy type II-III fractures. The literature on surgical management mostly includes open reduction and internal fixation (ORIF) for established non-unions with mixed results. Currently, little evidence exists on acute ORIF of displaced scapular spine fractures after RSA. Therefore, the purpose of this propensity score-matched study was to compare acute ORIF (<6 weeks) with non-operative management.

Methods: This retrospective case-control study included 74 Levy type II-III fractures from 3 surgical centers. Sixteen patients underwent acute ORIF within 6 weeks of symptom onset, and 58 patients non-operative management. In the operative group, 11 patients (69%) were treated with 90:90° double plating, 4 with hook plating (25%), and 1 (6%) with a hybrid double construct. Clinical (Subjective Shoulder Value (SSV), ASES score, VAS, patient satisfaction, and active forward elevation) and radiological outcomes were compared. Propensity score matching was performed using 5 criteria (age, sex, BMI, diagnosis, and Levy type) to balance the covariates and to reduce selection bias.

Results: Of the total group (74 fractures: 16 ORIF and 58 non-operative), 14 patients in each group were matched using the propensity score. At a mean follow-up of 3.7 years, the mean SSV was significantly better (p = 0.005) for the ORIF group (90%, IQR 76-90) compared to the non-operative group (57%, IQR, 42-70). The mean ASES score (82, IQR 74-90 versus 59, IQR 40-70), and mean active forward elevation (123°, IQR 95-137° versus 75°, IQR 50-100°) were significantly better in the ORIF group (p = 0.007 and p = 0.021, respectively) compared to the non-operative group. The union rate for the ORIF group was 93% (13/14), compared to 30% (4/13, 1 undetermined) for non-operative group (risk ratio 0.13, p = 0.001).

Conclusion: Acute ORIF for displaced Levy-type II and III scapular spine fractures after RSA is associated with significantly better clinical outcomes and union rates compared to non-operative treatment.