The patent in dispute solves the technical problem of providing a finger element that can be used as a self-contained, single-finger prosthesis with a simple structure that resembles a natural finger, and has the longest possible service life. A key feature is that the threaded worm is form-fitted to the drive shaft so that it can move axially and be guided axially by separate guides.

The court found that combining two prior art documents with a citation dating back over 70 years (NK19 from 1936), which fundamentally discloses the functional principle of the axially movable bearing, was not obvious.

‘If a functional principle has been known in itself for many decades, additional inspiration is generally required to apply this principle for the first time in devices whose intended use, structure, and mode of operation have also been known for many decades. ‘ In the present case, such inspiration for the application of this old principle was lacking.

A combination of the patent in dispute with documents from fields outside its area of expertise, such as the automotive sector (door lock mechanisms and power steering), was also deemed non-obvious.

The Federal Court of Justice emphasised that ‘whether and to what extent there is reason to seek solutions to a specific problem outside the field of technology in which the relevant question arises depends on the individual case’.

In this case, there were no concrete indications in prosthetics prior art that would have led to a search in these non-technical fields.

Furthermore, the problems in unrelated fields often focused on different aspects (e.g., noise prevention and ease of assembly) to those of the patent in dispute.

The court also did not consider that the feature of axially movable bearings, being a general means applicable to a wide variety of applications, was part of the specialist knowledge, particularly not in the context of finger prostheses. The textbooks and expert opinions submitted did not demonstrate that these specific relationships were considered objectively appropriate for preventing damage in the field of finger prostheses on the priority date.

Conclusion: This decision highlights the high standards required to demonstrate the obviousness of combinations within the scope of inventive step. It highlights that, even when functional principles are known, a specific reason or additional stimulus is required to apply them to new applications or in combination with other known technologies, particularly when the solutions are old or fall outside the field. This decision reinforces the protection of innovative technical solutions that cannot be deemed non-inventive merely by combining existing, unmotivated elements.