Similar Outcomes in Proximal Humerus Fractures Treated with Conventus Intramedullary Cage Device and Open Reduction Internal Fixation

Objectives: To compare clinical outcomes between open reduction and internal fixation (ORIF) with or without Conventus intramedullary cage (CC) for proximal humerus fractures. Methods: Design : Retrospective cohort study. Setting: Level 1 trauma center. Patient Selection Criteria: Included were patients that sustained OTA/AO 11B and 11C fractures treated with ORIF with or without CC with minimum one year follow-up. Outcome Measures and Comparisons: Primary outcomes included complication and reoperation rates. Secondary outcomes were American Shoulder and Elbow Surgeons (ASES) and Short Form 12 (SF-12) scores. Outcomes were compared between fixation strategies. Results: 56 patients were included, 33 ORIF and 23 CC, with mean follow-up of 5.0 (range 1.1-11.4) and 5.3 (range 2.3-7.6) years, respectively. The ORIF and CC groups were 27.3% and 21.7% male, respectively (p=0.759). The ORIF group had a higher mean age (68.2 ± 5.3 versus 64.2 ± 8.7 years, p=0.037). There was a higher proportion of OTA/AO 11C fractures in the CC cohort (65.2% versus 33%, p=0.029). CC group had a higher unplanned re-operation rate (18.2% versus 34.8% for CC, p=0.158) and complication rate (24.2% versus 39.1% for CC, p=0.233) which did not reach statistical significance within this available study population. Unplanned re-operations in the CC cohort included revision fixation (3) and conversion to hemiarthroplasty (2) or reverse total shoulder arthroplasty (3). There were no differences in ASES scores (mean 65.3 for ORIF and 63.1 for CC, p=0.773), physical SF-12 scores (mean 39.0 for ORIF and 42.1 for CC, p=0.342), and mental SF-12 scores (mean 50.3 for ORIF and 52.4 for CC, p=0.495) at final follow-up. Conclusions: OTA/AO 11B and 11C proximal humerus fractures treated with Conventus intramedullary cage augmentation demonstrated a trend toward higher reoperation and complication rates compared with standard ORIF, although this difference did not reach statistical significance. Midterm patient-reported outcome scores were similar between cohorts, suggesting that Conventus intramedullary cage augmentation may not provide additional clinical benefit. Level of Evidence: IV – retrospective cohort study