In case of knee instability, a surgical reconstruction of the VKB is carried out. This is now carried out by means of an arthroscopy (viewing operation), in which a tendon transplant from the leg (often of one of the hamstrings) is placed in the knee as a new crotch band (crossband reconstruction). This procedure is not very precise: in more than 20 % of patients, the crotch strap is secured in the knee at more than 5 mm from the original site. This leads to permanent instability, or to impaired function. In the long term, a vast majority of people who have undergone a cross-band reconstruction see an increase in wear (“arthritis”) of the knee.In recent years, extensive research has been carried out in the UMCG to determine the exact location of the crotch band on MRI images, and the processing of MRI images into practical tools or tools. The technological concept to be able to do this for a knee strap reconstruction has been studied, and there is a proof of concept. It seems possible from segmented MRI images to create a completely innovative, patient specific instrument using 3D printing. During the arthroscopy (view surgery) this mold is placed in its position, and then a drill hole is drilled from the outside to the exact location to which the band attaches to this individual patient via a drill guide. Then a new front crotch band can be reconstructed exactly, with an accuracy of < 2 mm. As a product, an innovative method of treatment will take place: The original attachment of the crotch band can be approached exactly to place the new band. This will be done through an innovative workflow: the MRI scan, which is made by default, is sent to Achilleon, where software technology makes a design for a target device. This design is printed, then returned to the doctor or hospital, where it is sterilised and used once during the operation. The final product is therefore a completely innovative workflow for the doctor, and an accurate and optimal targeting device.The operation will be better planned, and will last shorter: the pointer shows exactly the right place. Rehabilitation of the patient will go more smoothly: problems with a transplant that are not perfectly placed, which can limit recovery, are no longer encountered. There is significantly less chance of resurgence due to permanent instability, stiffness of the knee joint, or re-rupture of the new crotch band, as these complications are related to an impure position of the reconstruction. In the long term, we expect less wear of the joint because the optimal, natural, biomechanical properties of the knee have been restored. To achieve this, a consortium has formed under the direction of the orthopedics department of the UMCG, the patient practitioner. Part of this is the 3D lab of the UMCG: a scientific research and development institute focused on innovative application of imaging techniques in reconstructive surgery, and the company Achilleon, supplier of medical devices, with a lead role in the Netherlands in the field of patient-related 3D printing for braces and prosthetics.The primary product itself will be offered to the user as a “package”, not as a patient-related implant: by using a logistics system, a product price can be negotiated with the healthcare institution that is not directly subject to the limitations of the DBC system. By concluding a licensing agreement, a larger, internationally oriented supplier of surgical instruments worldwide can make use of the project result Achilleon can enter the market for medical precision instruments for musculoskeletal reconstruction, and use this applied technique to deliver multiple precision instruments. The orthopedes in the North of the Netherlands are involved in the project early, through scientific meetings and information sessions, during which their wishes are also taken into account in the final production phase. Of this market, we aim for a 50 % market share. The National Market is approached through scientific lectures and publications, with stands at congresses. In the end, we want 30 % of the market. The international market is approached through an international supplier of medical instruments in this field. A licence agreement can then be concluded with that.