Reverse total shoulder arthroplasty policy in Germany – an analysis of the health care reality from 2010 to 2022

The last few years have been characterized by increasing numbers of reverse shoulder arthroplasties. In addition to the classic indication of cuff tear arthropathy, the use for complex proximal humeral fractures (PHFs) and rotator cuff tear (RCT) in very old patients have been established. The objective of this study is to clarify and substantiate the above statements specifically for Germany (based on official data from 2010 to 2022). Since substantial changes in the structure of the population are expected over time, all data must be adjusted for these changes. The hypotheses are (1) the German population is ageing with a shift to more elderly patients over time, and (2) the general use of shoulder arthroplasty (total anatomic - shoulder arthroplasty (aTSA) and reverse - rTSA) has increased during the time period, but the effect is beyond the shift of age stratification but attributable to a change of hospital admissions and surgical therapy for PHF and RCT. In this retrospective study, data were collected from the National Bureau of Statistics in Germany for the period of 2010 to 2022. Three different data sources were combined for the analysis: a database regarding the structure of the population in age groups for every year, a database reporting relevant operation codes, and the data on hospital admissions based on ICD-10 codes. The relevant data were extracted and combined using Excel spread sheets (Microsoft Corporation, version 2019). Absolute numbers are reported and adjusted for 100.000 inhabitants in each age group in order to calculate the incidence. Only slight change in absolute numbers of the population (n = 81751602 to 84358845, +3%) was observed, but a substantial shift toward the group of elderly people: the peak age group has shifted from 40-50 to 55-65. The number of TSA has significantly increased (n = 15000 to n = 28117, +187%; incidence 18.35 to 28.53, +155%). The number of rTSA has largely increased (n = 5326 to n = 24067, +452%; incidence 6.51 to 28.53, +438%), whereas the number of aTSA steadily decreased (n = 9674 to n = 4050, -42%; incidence 11.83 to 4.80, −41%). The number of revision arthroplasties has increased 1.8-fold (n = 2179 to n = 3893; incidence 1.7-fold). The peak revision rate shifted from the age group 70-75 toward 90- 95; 76% of all revision cases were performed in patients 65 years and older in 2010 increasing to 87% in 2022. Hospital admissions for PHF have increased 7.8-fold (n = 110091 to n = 810907). The peak