The CapFlex PIP prosthesis is a new and innovative joint replacement for the second knuckle. Current prostheses are fixed into the bone via long intramedullary stems. The idea to minimize the implant volume led to the artificial knee joint in miniature format and thus the replacement of the joint surfaces with anatomically designed congruent components. In order to do justice to the patient’s individual anatomy, the modular designed prosthetic components are available in different sizes. To offer a controllable modularity was of particular concern. The advantages for the patient resulting from the new design are a primary solid bone anchorage with limited bone resection, the improved lateral joint stability and the optimized conditions for revision. For reliable step-by-step implantation of the prosthesis, color coded and intuitive instruments are available which are arranged according to the sequence of use in surgery. The storage, optimized for reprocessing requirements, is drawer-based, enabling equally optimal access to all sizes of instrument.