Orthopaedic Progress and Specialisation in the aG-DRG System: An Analysis from the Perspective of a Centre of the National Centre for Tumour Diseases with a Focus on Bone Sarcoma.

The implantation of a tumour prosthesis for neoplastic indications can be considered to be a rare operation. After each tumour resection, the defect reconstruction plays a crucial role and always requires an individualised solution. In addition to modular tumour prostheses and growth prostheses for children, joint-preserving custom implants are being increasingly used. In most cases, the specific Diagnosis Related Groups (DRGs) I95A or I95B, which are available for tumour prostheses, are billed to the payers. The complex treatments require high professional expertise and are predominantly performed in specialised centres.This study addresses how these specialised services with various defect reconstructions achieve cost coverage within the modified DRG (aG-DRG) system in a university hospital centre.In this retrospective cost analysis, data from a university hospital were included for the period from mid-2021 to the end of 2023. The analysis considered case-related costs (personnel and material costs for surgery and on the ward, as well as service utilisation in functional areas). The actual costs were determined according to the current guidelines of the calculation manual issued by the German institute for the remuneration system in hospitals (InEK). As a result, each patient's internal hospital costs were compared with the respective cost blocks of the aG-DRG matrix.In total, 198 patients could be included, with an average age of 43.7 years (SD: 25.5), with a reduction of 2.7 days in the average length of stay compared to the duration specified by InEK.The cost-revenue analysis revealed an average undercoverage of € -1,223 per patient. The greatest discrepancy was found in the implant costs, with a hospital-specific undercoverage of € -1,445, primarily due to the location and the use of patient-specific implants. Both characteristics were identified as risk factors. The intensive care unit's costs and service utilisation in functional areas, particularly radiology and laboratory services, were lower in this patient group compared to the benchmark hospitals. These could almost compensate for the higher personnel costs of physicians - with a shortfall in both the operating theatre and on the normal ward.Despite its high specialisation, one of Germany's leading tumour orthopaedics centres is currently not reaching cost-coverage for the implantation of tumour prostheses. This is mainly due to the various types of bone defects that need to be treated following tumour resection. Surgeons are expected to achieve high functionality and limb preservation, which places significant demands on them. Each prosthesis implantation involves an individualised solution with varying costs for the implant. The current aG-DRG system does not adequately account for this individuality and the broad spectrum of a major centre. The introduction of flat fees for the availability of services will not improve the situation. A first step toward fairer compensation could be the implementation of a hospital-specific additional payment for custom implants.