We reviewed the clinical and radiographic results of fourteen patients who had a severe deficiency of bone and were managed with a massive allograft in conjunction with a standard total knee prosthesis between 1987 and 1990. The etiology of the bone loss included the failure of a previous total knee prosthesis, a supracondylar fracture of the femur or a fracture of the proximal part of the tibia, and debridement during the first stage of a reconstruction for the treatment of an infection. Thirteen patients had satisfactory clinical and radiographic results after the index procedure. The knee score of The Hospital for Special Surgery improved from an average of 24 points (range, 0 to 54 points) preoperatively to 82 points (range, 37 to 98 points) at the time of the most recent follow-up examination. The average duration of follow-up was forty-three months (range, twenty-nine to sixty-three months). The radiographic and functional results compare favorably with those that have been reported in most studies of otherwise comparable patients who had less deficiency of bone. While considerable risks are associated with the use of allograft bone and the true longevity of reconstructions with such bone is not yet known, the initial and short-term follow-up results support the use of allograft for the restoration of a functional knee joint in a patient who has a severe deficiency of bone.