Comparison of outcomes of internal fixation and non-operative management of 2-part and 3-part proximal humerus fractures in younger adults

Aims: This study aimed to compare outcomes of internal fixation and non-operative management in younger adults. Methods: A retrospective cohort study was undertaken in patients aged 18–55 with 2-part or 3-part proximal humerus fractures at a Level 1 trauma centre from January 2010 to December 2018. Outcome measures were the Oxford shoulder score (OSS), EQ-5D-5L, and radiological outcomes. Complications recorded included further surgery, loss of position/fixation, and non-union/malunion. Statistical analysis included univariable analysis and multivariable analysis performed using binary logistic regression and linear regression. Results: A total of 184 eligible patients were included; 99 underwent operative fixation and 85 were managed with sling immobilisation. The mean (SD) age in the operative group was 39.3 ± 10.6 and in the non-operative group was 43.2 ± 10.8 (p = 0.02). Seventy-seven percent completed a minimum 12-month follow-up (median 3.2 years, IQR 2–6.5 years). Most 3-part fractures were treated surgically (78%), as opposed to 44% of 2-part fractures. All open fractures, all segmental fractures, eight head split fractures (89%), and 12 fracture-dislocations (80%) were treated surgically. There was no difference in mean OSS (43.7 operative vs 42.1 non-operative, p = 0.27), mean EQ-5D-5L utility score (0.81 vs 0.78, p = 0.32) or proportion returned to work (83% vs 75%, p = 0.34). Adjusted for case-mix, there was no difference in OSS (adjusted mean difference 0.24, 95%CI −2.73 to 3.22, p = 0.87) or EQ-5D-5L utility score (adjusted mean difference 0.00, 95%CI −0.06 to 0.07, p = 0.96). The complication rate was high (36% non-operative, 27% operative, p = 0.24). A higher rate of varus malunion was observed in the non-operative group (24.0% vs 41.4%, p < 0.001). Following operative management, 23% underwent subsequent surgery compared with 7% of the non-operative group (p = 0.002). Conclusion: In younger adults with proximal humerus fractures no differences in patient reported outcome measures were observed between groups. Operative management was associated with improved radiological outcomes, but a higher rate of subsequent surgery.