Compression arthrodesis can be used as a salvage procedure in failed total knee replacement. In fourteen patients so treated, the fusion failed in five. As regards the cause of failure, the most important factor was technical inadequacy of the arthrodesis procedure; that is, the required stable fixation and solid bone-to-bone contact. In procedures that we considered technically adequate, there was fusion in seven of the nine knees. The fusion seemed to be delayed in these patients, averaging 5.3 months (range, two to twelve months). Fixation with a double clamp seemed to be more effective than with a single clamp.