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

Background: 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.

Methods: 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.

Results: 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 in the age groups has shifted by a decade from 70-74 to 80-84. The absolute number of surgical therapy for PHF has decreased (n = 12816 to n = 9562, 75%; incidence 72%). The number of hospital admissions for RCT increased by 2.6-fold (n = 47004 to n = 124096; incidence + 255%). The number of surgical interventions for RCT increased by 3.7% (n = 51350 to n = 53294; incidence 62.8 to 63.2). Combined numbers for the operative therapy of PHF, RCT, and rTSA show an increase of +124% (n = 69491 to n = 86715) with a peak shift on one decade toward the age group 60-94 with 79% of the patients in 2022. The increased use of rTSA, as expressed by incidence, is strongly correlated with the increasing proportion of people aged 65 and over.

Conclusion: The data show a substantial increase in the use of shoulder arthroplasty procedures in Germany in the observed time period, with the main driving factor being the increase of rTSA, whereas aTSA numbers decreased. The combined analysis of the hospital admissions and operative procedures performed to treat PHF and RCT indicated a shift of treatment numbers from open reduction and internal fixation and rotator cuff repair in the elderly toward the alternative use of rTSA in this age group. The observed shift of the stratification of age groups gives a further explanation for the increase in rTSA use: the number of patients in the age groups with the typical and alternative indications for rTSA substantially increased with a shift of the peak age group towards the elderly of one decade. Healthcare officials should be aware of these fundamental changes in the population, which create further demands on the health care system. The expected continuation of rising numbers of rTSA needs to be addressed by providing adequate resources such as reimbursement, surgical and rehabilitation facilities, and staff.