Predictors of soft-tissue complications and deep infection in allograft reconstruction of the proximal tibia

Reconstruction of the proximal tibia after wide resection of malignant tumors in the pediatric population is very challenging. Advocates of allograft reconstruction argue as advantages bone preservation, biological reconstruction that facilitates reattachment of the extensor mechanism and other soft-tissue structures, delay of metallic prosthesis use and preservation of the distal femoral growth plate. However, complications are significant, infection being very common.

Under IRB-approved protocol, 32 patients (17 males, 15 females), 13 years old in average (2-20), who underwent 33 allograft reconstructions of the proximal tibia, were evaluated for the occurrence of soft-tissue complications and/or deep infection (infection affecting the allograft). Potential predictors of soft-tissue complications and deep infection, categorized as pre- and perioperative variables, were analyzed in relation to the risk for developing a soft-tissue complication or a deep infection.

The prevalence of soft-tissue complications was 48% (16/33). However, we were not able to identify any significant predictors. The prevalence of deep (allograft) infection was 15% (5/33). Multivariate logistic regression determined higher BMI at the index surgical procedure and lower pre-operative WBC to be independent predictors of deep infection. For each unit of increase in BMI, the odds of deep infection increased by 40% (OR = 1.40; CI = 1.07-3.06; P < 0.05). For each one unit (1,000) of increase in the pre-operative white cell-count, the odds of deep infection decreased by 70% (OR = 0.30; 95%CI = 0.01-0.89; P < 0.05). Four of the five deep infections were in patients with soft-tissue complications, mainly wound dehiscence. However, wound dehiscence or soft-tissue complications were not predictive of deep infection.

Soft-tissue complications are prevalent in allograft reconstruction of the proximal tibia. Prevention is important as these may progress to deep infection. Careful attention to nutritional (BMI) and immunological status may help in patient selection for allograft reconstruction. If allograft reconstruction is opted for, efforts should focus on optimization of these factors as they proved to be independent predictors of subsequent deep infection. J. Surg. Oncol. 2016;113:811-817. © 2016 Wiley Periodicals, Inc.