RESUMO
OBJECTIVES: The aims of our study are (1) to explore the risk factors of mechanical failure (MF), (2) to figure out an index to evaluate this risk, and (3) to select an optimal reconstruction strategy to reduce this risk. METHODS: We retrospectively reviewed 104 patients from Dec. 2008 to Mar. 2016, undergone extensive knee curettages in our institution. Radiographs and post-operative interviews were used to classified cases of MF. Relative factors (age, tumor location, the invaded area, etc.) were also collected and analyzed by SPSS software. RESULTS: Thick subchondral bony layer (p = 0.006) and combined grafting of the cement and bone (p = 0.006) had lower risk of mechanical failure. Mechanical failure appeared to happen in the femur (p = 0.012) more easily. The ROC curve (AUC = 0.722) reveals that less post-operative bony layer (≤ 3.3 mm) is more likely to cause mechanical failure. The Kaplan-Meier survival curve showing increased survival in those patients after a combination grafting surgery (HR, 3.799; p = 0.006). CONCLUSION: Based on our study results, combined grafting of the cement and bone reduced the risk of mechanical failure in the knee due to the thin subchondral bone layer (SCB), especially in the femur.