The invention pertains to a fixation
system for ligamentoplasty including a cage including a longitudinal borehole including a proximal end and a distal end, an outer surface including a thread, a
distal portion wherein the borehole is tapered, a medial portion, an internal part designed to be inserted into the opening of the cage including a tapered distal part, a central part, a proximal part including a thread, wherein the cage includes a proximal portion with a cross-section larger than that of the medial portion thereby forming a collar, and wherein the borehole has a cross-section larger than that of the medial portion, the borehole including a thread over an
angular sector of less than 360° (a portion of its circumference) designed to engage with the internal part.