ObjectiveTo evaluate the effect of bone cement filling on articular cartilage injury after curettage of giant cell tumor around the knee. MethodsFifty-three patients with giant cell tumor who accorded with the inclusion criteria were treated between January 2000 and December 2011, and the cl inical data were retrospectively analyzed. There were 30 males and 23 females, aged 16-69 years (mean, 34.2 years). The lesion located at the distal femur in 28 cases and at the proximal tibia in 25 cases. According to Campanacci grade, there were 6 patients at grade I, 38 at grade Ⅱ, and 9 at grade Ⅲ. Of 53 patients, 42 underwent curettage followed by bone cement fill ing, and 11 received curettage followed by bone grafts in the subchondral bony area and bone cement fill ing. Two groups were divided according to whether secondary osteoarthritis occurred or not during postoperative follow-up. The gender, age, lesion site, the subchondral residual bone thickness, tumor cross section, preoperative Campanacci grade, subchondral bone graft, and Enneking function score were compared between 2 groups, and multivariate logistic regression analysis was done. ResultsAll incisions healed by first intention. The average follow-up time was 65 months (range, 23-158 months). Of 53 cases, 37 (69.8%) had no osteoarthritis, and 16 (30.2%) had secondary osteoarthritis. Three cases (5.7%) recurred during the follow-up period. Univariate logistic regression analysis showed no significant difference in gender, age, lesion site, and Campanacci grade between 2 groups (P>0.1); difference was significant in the subchondral residual bone thickness, tumor cross section, Enneking function score, and subchondral bone graft (P<0.1). The multivariate logistic regression analysis showed that the decreased subchondral residual bone thickness, the increased tumor cross section, and no subchondral bone graft are the risk factors of postoperative secondary osteoarthritis (P<0.05). ConclusionCurettage of giant cell tumor around the knee followed by bone cement filling can increase the damage of cartilage, and subchondral bone graft can delay or reduce cartilage injury.