Cemented vs. uncemented reverse total shoulder arthroplasty for the primary treatment of proximal humerus fractures in the elderly - A retrospective case-control study

Background: Uncemented reverse total shoulder arthroplasty (RTSA) for the primary treatment of proximal humerus fractures (PHF) in elderly patients was introduced at our institution in 2017. Recent reports have raised concerns about increased rates of early bone resorption at the proximal humerus with uncemented fracture stems. The aim of this study was to find out whether there was any difference in functional or radiographic outcomes between cemented and uncemented RTSA for PHF. Methods In 2017 and 2018, 17 consecutive patients with uncemented RTSA were included (group nC). We added 34 age and sex matched patients (propensity score matching 1:2) who had undergone cemented RTSA for PHF from 2011–2016 (group C). These two groups were compared in terms of clinical and radiographic outcomes at 2 years after the index surgery. Results The mean bone quality was low in both groups: in group nC the deltoid tuberosity index (DTI) was 1.43 (1.22–1.72) and in group C 1.42 (1.22–1.67). At the final 2 year follow-up, the relative CS was 98.3% (71–118) in group nC and 97.9% (36–125) in group C (p = 0.927); the absolute CS was 70.2 (49–89) in group nC and 68.0 (30–94) in group C (p = 0.509). Lucent lines at the humeral site were seen in 8 cases (47%) in group nC and in 13 cases (38%) in group C (p = 0.056). Compared to 3% in group C, all patients in group nC showed at least grade 1 and 65% showed grade 3 bone resorption at the proximal humerus, (p < 0.001). Conclusion Compared to cemented RTSA bone resorption at the proximal humerus was significantly more frequent in patients with uncemented RTSA for PHF. So far, this is rather a radiographic than a clinical finding, because both groups showed very successful functional outcomes and low revision rates at the 2 year follow-up. Level of Evidence III: a retrospective case-control study