Modular megaprosthesis (MP) and allograft-prosthetic composite (APC) are the most commonly used reconstructions for large bone defects of the proximal tibia. The primary objective of this study was to compare the two different techniques in terms of failures and functional results. A total of 42 consecutive patients with a mean age of 39.6 years (range 15-81 years) who underwent a reconstruction of the proximal tibia between 2001 and 2012 were included. Twenty-three patients were given an MP, and 19 patients received an APC. There were nine reconstruction failures after an average follow-up of 62 months: five in the MP group and four in the APC group (p=0.957). The 10-year implant survival rate was 78.8% for the MP and 93.7% for the APC (p=0.224). There were no relevant differences between the two groups in functional results. Both MP and APC are valid and satisfactory reconstructive options for massive bone defects in the proximal tibia. In high-demanding patients with no further risk factors, an APC should be considered to provide the best possible functional result for the extensor mechanism.