The entire GMK Total Knee Replacement System has been designed to preserve the joint functionality without dramatically altering its anatomy and kinematics, even in cases of severe ligament instability or massive bone defects. Thanks to the GMK Hinge comprehensive range of options the surgeon can address very unstable knees without compromise, restoring the confidence of movement for his patients. The stress-free modular mechanism of GMK Hinge implant, together with its bone preserving design, help the surgeon to address demanding joint salvage procedures as well as unstable primary surgeries where the clinical indications show evidence of a constrained implant. Intuitive instruments help the surgeon to minimise the number of intra-operative steps and be confident that a standardised procedure will make the entire surgery more efficient and time saving.