Revision TKR is a domain of constrained and hinged TKR. Revision TKR is often complicated by instability (Fig. 55.2), dislocation (Fig. 55.3), severe bone loss (Figs. 55.4 and 55.5), wear problems, periprosthetic fractures, and periprosthetic joint infection. These complications represent indications for the implantation of hinged devices in order to achieve stable mechanical fixation as well as reconstruction of limb alignment, joint line, soft tissue balancing, and bone defects. As shown in Table 55.1, Lombardi et al. developed an algorithm for appropriate implant choice depending on the extent of instability [2].