Improved outcomes of elderly patients with acute and displaced proximal humerus fractures treated with window bone ingrowth fracture-specific stem reverse shoulder arthroplasty

Abstract

Abstract Background: The optimal treatment of displaced proximal humerus fractures (PHFs) in the elderly population remains controversial. Reverse shoulder arthroplasty (RSA) is a popular surgical treatment option that provides improved and reproducible results. However, the relevance of fracture-specific stem designs for RSA to improve tuberosity consolidation and shoulder function remains debatable. Methods: This study included all patients 70 years or older with acute and displaced PHFs primarily treated with RSA at a single institution between January 2010 and December 2019 who participated in a minimum follow-up of 2 years. Exclusion criteria were pathologic fractures and more than 6 weeks between fracture onset and the time of surgery. Results: A total of 112 patients (15 men and 97 women) with a median clinical follow-up of 52 months were included. The mean age at the time of fracture was 78.6 years. The mean time from trauma to surgery was 6.9 days. The mean length of the postoperative hospital stay was 5.2 days. According to the Charlson comorbidity index, 41 patients had a score of 4, and 17 patients had a score ≥ 6. All fractures were classified as Neer types 3 and 4 (n = 50 and n = 62, respectively). Most patients had American Society of Anesthesiology scores II and III (56% and 40%, respectively). A fracture-specific humeral implant was used for 86 patients, and a conventional humeral stem was used for 26 patients. Regarding the tuberosity fixation technique, 76 tuberosities were attached using technique A and 36 tuberosities were attached using technique B. The overall survival rate during the 2-year follow-up was 88.2%; however, this decreased to 79% at 5 years. Most patients returned to normal activities of daily living, and 45.5% of the patients achieved functional mobility. Only three patients had complications (two infections and one dislocation) requiring revision surgery. In the multivariable analysis, the tuberosity fixation technique (P = 0.012) and tuberosity anatomical consolidation (P < 0.001) were associated with improved Constant scores. Fracture-specific humeral implants (P = 0.051), the tuberosity fixation technique (P = 0.041), tuberosity anatomical consolidation (P < 0.001), and dementia influenced the achievement of functional mobility (P = 0.014). Tuberosity anatomic consolidation was positively associated with bone ingrowth fracture-specific humeral implants (P < 0.01) and a strong tuberosity fixation technique (P < 0.01). Conclusion: RSA is used for complex and displaced fractures of the proximal humerus in elderly patients. Dementia was negatively correlated with functional outcomes. A window bone ingrowth fracture-specific stem combined with strong tuberosity fixation can yield better clinical and radiological results.