This may be because the tumor involved a large different portion of the bone, large amounts of muscle were resected leaving insufficient soft tissue support, and extended dead space remained. All the patients in this cohort had extensive soft tissue repair and functional reconstruction of muscles attached to pelvis. Short-term limb function after surgery was satisfactory. In 2 of the 6 patients who had allogeneic acetabular reconstruction, bone absorption at the pubic end was seen 12 months after surgery; however, limb function and quality of life were not affected. Complications such as bone ingrowth, loosening, and breakage after large allogeneic bone transplantation are problems that remain to be solved.

2 , 8 , 15 – 19 The primary postoperative complications of prosthesis placement combined with allogeneic bone transplantation are wound infection, internal organ and nerve injury, and implant fracture or translocation. 1 , 9 , 20 – 21 The reported incidence of infection after allogeneic bone implantation is 15-50% 14 , 22 with the primary reason for infection being incorrect preparation before implantation. Allogeneic bone tissue used in our cohort was processed at 130��C at 6.8 kg pressure for 3-5 min. This bone tissue had high safety, low immunogenicity, a natural structure, and was easy to apply. Among the 9 patients, only 1 developed an incision wound infection (11%). The infection rate was lower than that reported in the literature.

Possible reasons for the low infection rate include improved allogeneic bone preparation (eliminating allogeneic antigens and bacteria), appropriate preoperative disinfection and postoperative wound care, use of a drainage tube for at least 5-7 days, prophylactic antibiotics, skilled surgical technique, and short duration of surgery. The operative time was not statistically different between the 2 groups, but was clearly greater in the allograft reconstruction group (4.9 h [4.1, 5.6]) as compared to the en bloc resection group (4.0 h [3.3, 4.4]). In both procedures, the tumor resection steps are similar. In allograft reconstruction, the allograft and fixation plates are prepared before the surgery and thus in most cases the reconstructionprocess is smooth and without complications. The most likely reason for the difference in surgical time not being statistically different is the small number of cases.

We also noted that the complication rate was similar between the groups, while reconstruction is typically associated with a higher rate of complications than resection. In this study, all surgeries were performed by the same surgeon, and thus the surgical technique including strict AV-951 hemostasis and the placement of drains were the same for all patients in both groups. In addition, strict protocols were followed for preparation and handling of the grafts. Loosening problems can occur with any prosthesis, though we did not see any in this study up to 12 months.