AIM. To present our experience in patients treated under primary diagnosis giant cell tumor of bone at Department Orthopaedic Surgery Zagreb University School of Medicine in a 15-year period from 1995 to 2009. METHODS. We performed a retrospective study of all patients treated in our Department because of giant cell tumor of bone (GCT) from 1995 to 2009. The mean age of our patients was 29,9 years (range: 14 to 70 years). Sex distribution showed prevalence in female (F:M=23:12=66%:34%). All together, 39 patients were operated under primary diagnosis of GCT. Four patients were lost in follow-up. In total, 35 patients were included in study. Diagnosis of GCT was made according to clinical, imaging and histological findings, and distributed by Campanacci's classification. RESULTS. Not including diagnostic biopsy, 84 operations were performed on 35 patients. Fourteen patients (40%) had GCT grade 1, fourteen (40%) had GCT grade 2, and seven (20%) had GCT grade 3. From the first symptoms to diagnosis there was an average duration of 7 months (range: 0 to 24 months), where the main symptoms were pain and swelling of affected bone and/or joint. GCT was localized in distal femur (n=12, 34%), proximal tibia (n=10, 29%), distal tibia (n=4, 11%), distal radius (n=3, 9%), and other locations (n=6, 17%). Patients with less aggressive GCT (grades 1 and 2) were treated with marginal excision: excochleation and reconstruction with bone transplant (n=12, 34%). In patients with locally more aggressive tumor (grades 2 and 3), “en bloc” resection and reconstruction with tumor endoprosthesis or bone transplant was performed (n=22, 63%). Due to localization of tumor, one patient was treated with radiation (3%). Complications were recorded in 12 patients (34%), and are shown as total number and percentage of all complications. Complications were the most common in knee region, proximal tibia (n=4, 33%) and distal femur (n=3, 25%). Also, the complications occured more frequently after “en bloc” resection (n=7, 58%). GCT classified as gradus 2 had most complications (n=5, 42%) till GCT classified as gradus 3 had least (n=3, 25% of complications, 9% of all). We recorded and treated local recurrence of tumor (n=6, 50%), infection (n=2, 17%), and mehanical complications of endoprosthesis (n=2, 17%). Due to local recurrences, in 2 patients underlying osteosarcoma was revealed, and they were treated with amputation. CONCLUSION. Each patient with GCT should be treated individually. Regardless non-malignant attribute, local behaviour of tumor determines treatment approach according to treatment principles of malignant tumor of bone. Number of complications in our patients is relatively high, recorded in one third of our patients, which matches the literature in announced studies

Background. Giant cell tumours of bone (GCT) are benign bone tumours with a locally aggressive character. Local recurrence is considered the main complication of surgical treatment and is described in up to 50% of patients. Intralesional curettage with the use of adjuvants like phenol or polymethylmetacrylate (PMMA) is recommended as initial treatment, significantly decreasing the risk of recurrence. However, risk factors for local recurrence in skeletal GCT have not yet been firmly established and a golden standard for local therapy remains controversial. Objective. The identification of risk factors predisposing for an increased risk of local recurrence. In addition, different surgical techniques are compared to identify the optimal surgical approach for the identified risk factors. Methods. In a retrospective study all 215 patients with bone GCT treated between 1964 and 2009 in one centre were included, of which 193 were suitable for analysis. All patients had minimal follow-up of 12 months (mean 115; range 12–445). Using a Kaplan Meier survival analysis recurrence free survival rates were calculated. Cox-regression was used to determine the influence of different types of therapy, the use of adjuvants, and various patient and tumour characteristics. Results. The mean local recurrence rate for all patients was 35.2% (n=68, 95%CI: 28.3–42.1). Recurrence rate after wide resection was 0.17 (n=6, 95%CI: 0.04–0.29), after curettage with adjuvants 0.32 (n=42, 95%CI 0.24–0.41) and after curettage alone 0.74 (n=20, 95%CI: 0.57–0.91, p < 0.001). Soft tissue extension (Hazard Ratio: 3.8, p < 0.001), localisation in radius and ulna (HR: 2.6, p=0.013), and surgical experience (HR: 2.2, p=0.022) were identified as significant general risk factors for local recurrence. For intralesional resection, Campanacci grade III (HR: 3.9, p=0.019) and location in axial skeleton (HR: 3.3, p=0.016) additionally significantly increased this risk. Comparing treatments our data showed that curettage followed by adjuvants was superior to curettage alone (p < 0.004), and the application of both phenol and PMMA did not present a significantly better outcome than curettage and PMMA alone (HR: 1.07, p=0.881). Conclusion. Of all possible risk factors only soft tissue extension, localisation in radius and ulna and non-radical resections significantly influenced the risk of local recurrence for all treatments. In addition, we found that high-grade tumours and localisation in the axial skeleton were additional risk factors for local recurrence after intralesional surgery. Although wide resection increases patient morbidity, it can be the therapy of choice in high risk patients. Intralesional therapy can be advised for low recurrence risk patients using curettage and PMMA only, whereas our study could not confirm the predicted effect of phenol as an additional adjuvant