BACKGROUND Rotating-hinge total knee prostheses may be used for the treatment of global instability about the knee. The designs of previous generations were associated with suboptimal outcomes. OBJECTIVE We evaluated the clinical and radiographic outcomes of salvage knee reconstructions using modern-generation, modular, kinematic rotating-hinge total knee prostheses. METHODS We retrospectively reviewed 26 rotating-hinge arthroplasty devices to examine whether acceptable results were obtainable using a single arthroplasty design. The average age of the patients was 77 years (SD, 9 years); the minimum followup was 24 months (mean, 46 months; range, 24-107 months). The indication was revision surgery in 21 patients and complex primary surgery in five. Patients were evaluated clinically (Knee Society score) and radiographically (positions of components, signs of loosening, bone loss). RESULTS Knee Society pain scores improved from 40 preoperatively to 77 postoperatively, and function scores improved from 36 to 51. ROM improved from -15 masculine to -10 masculine. None of the patients' knee pain or function worsened. No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in three knees. Three patients required reoperations: one showed a supracondylar periprosthetic fracture treated by open reduction and internal fixation, whereas the other two had periprosthetic infections. CONCLUSIONS Reconstruction with rotating-hinge total knee prostheses can provide substantial improvement in function and a reduction in pain in extreme circumstances, such as gross instability. We believe this salvage procedure should be reserved for severe ligamentous deficiencies in elderly and sedentary patients or whenever revision surgery techniques fail. METHODS Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.