Objective To analyze the clinical features, treatment methods, and recurrence factors of giant cell tumor of the bone and to investigate the surgical therapy choice for the tumor around the knees. Methods Thirty-eight patients (13 males and 25 females; average age 31.1 years, range 14-59 years) withgiant cell tumor of the bone were treated and followed up from January 1993 to January 2005. The patients’ diagnoses were established by biopsies of the specimens from the preoperative punctures or operations. The clinical features and the radiological and laboratory data from the 38 patients were reviewed. By the Campanicci’s radiological grading system, 5 patients were in Grade Ⅰ, 22 in GradeⅡ, and 11 in Grade Ⅲ. By the Enneking classification, 9 patients were in Grade Ⅰ, 21 in Grade Ⅱ, and 8 in Grade Ⅲ. By the Jaffe’s classification, 7 patients were in Grade Ⅰ, 24 in Grade Ⅱ, and 7 in Grade Ⅲ. The intralesional excision (curettage) with the bone grafting was performed on 4 patients; the curettagewith some adjuvant treatments (highspeed burring, phenol, alcohol, cement, hydrogen peroxide, 50％ ZnCl2, 3% iodine tincture, or bone cement) was used in 26 patients; and resection of the whole tumor was performed on 8 patients. Results The follow-up of the 38 patients for 12-144 months (average, 67 months) revealedthat giant cell tumor of the bone was found around the knees in 29 of the 38 patients (13 at the distal femur, 16 at the proximal tibia), at the proximal femurin 2, at the proximal ulna in 2, at the distal radius in 2, at the sacroiliac area in 2, and at lumbar spine in 1. Of the 38 patients, 4 had a recurrence after simple curettage, 8 had no recurrence after resection of the whole tumor, and 8 of the remaining 26 patients had a recurrence after curettage with some adjutant treatments. Five patients in Grade Ⅰ (Campanicci’s radiological grading) hadno recurrence, 6 of the 11 patients in Grade Ⅱ had a recurrence, and 6 of the 11 patients in Grade Ⅲ had a recurrence. Two of the 9 patients in Grade Ⅰ (Enneking grading) had a recurrence, 6 of the 21 patients in Grade Ⅱ had a recurrence, and 4 of the patients in Grade Ⅲ had a recurrence; all the recurrent lesions were around the knee, with a duration of the recurrence ranging from 2 months to 36 months (average,14.3 months). Of the patients with the recurrence, 12 underwent reoperations (8 by the total resection of the recurrent tumor, 4 by the curettage with adjuvant treatments), and there was no recurrence after the reoperation. Conclusion Giant cell tumor of the bone usually recurs around the knee joint, especially at the proximal tibia, usually graded as Grade Ⅱ or Ⅲ bythe Campanicci’s radiological grading system. Simple curettage has a higher recurrence rate; therefore, extensive curettage and resection of the lesions combined with some adjuvant treatments after the correct diagnosis can beused to reduce the high recurrence rate of giant cell tumor of the bone.