Introduction: The today’s applied osteotomy techniques in surgical orthopaedics have to adapt on the requirements on modern operationprocedures. The application of abrasive water jets offers the possibility to realize a self-defined, athermic precise cut in biological hard tissues. The small process forces indicate the application of modern handling systems. Process engineering and visions of a clinical conversion were demonstrated. Methods: With biocompatible crystalline abrasives freely defined separation cuts and open space geometries, which correspond to the contour of a knee endoprosthesis, were realized at human bones for the first time. The used abrasives (sucrose, xylitol) and can be added in mass flows of 10–20% and the physiological osmolarity is not exceeded after material removal and following dissolution. The necessary pressure level was 75MPa, which only corresponds to a fraction of the necessary pressure of pure water jet. The analysis about quality of the cut-surfaces was done laser-optical. Results: The transect performances of the used abrasives are similar. The arithmetic roughness Ra was 5μm with a pressure level of 75MPa. The value was found by surface detection 3mm under the point of entrance of the water jet in the bones. The flow mass of the abrasives showed only a small influence on the roughness. Conclusion: The results concerning angle deviation and surface seems to be were very promising.