Abstract: To analyze the biomechanics characteristics of broken tumor prosthesis and optimize it with a finite element method and to evaluate the sleeve prosthesis in revision for custommade tumor prosthesis fracture. MethodsThe CT data of femur treated by software Mimics were imported into software UG2.0 to make models, and the prosthesis models were made based on the prosthesis dimension. Then the femur and prosthesis were assembled as the operations did and imported into a threedimensional finite element software ABAQUS6.5 to make a mechanics loading analysis. The sleeve revision prosthesis was designed to repair fracture of the extramedullary site of custommade tumor prosthesis with no losing. ResultsIn the broken prosthesis, conjunction of the femoral neck and the extramedullary site, conjunction of the extramedullary site and intramedullary site, one third of the intramedullary site on the exterior and interior had stress concentration, but stress of the extramedullary part was weak. Followed up for 19 months, no infection, losing, fracture of prosthesis, recurrence and metastasis, inequality of lower limb were observed. The Enneking score of preoperation was 1, of postoperation was 26, and of the last followed-up was 25. ConclusionWe should strengthen many aspects of custommade tumor prosthesis on the stress concentration site such as the diameter, shape and material. Sleeve revision prosthesis has a highly value and a good initial clinical effect in its indication.

Key words: Hip prosthesis, Revision, Sleeve joint prosthesis, 3-D finite element