Is higher body mass index associated with secondary osteoarthritis in patients treated with bone cement for benign aggressive bone tumors? Long-term evaluation of 43 patients.

Background: This study was designed to investigate the secondary osteoarthritis rate in patients with benign aggressive bone tumors treated with curettage and cementing at long-term follow up.

Methods: Patients diagnosed with benign aggressive bone tumor (giant cell or aneurysmal bone cyst), treated with extended curettage and cementation with polymethylmethacrylate, who had a minimum of 60 months of follow up after surgery were included in this study. After definitive diagnoses were confirmed by a histopathologist, we decided to perform standard surgical management. Osteoarthritis was staged radiologically using the Kellgren-Lawrence scoring system, and the contralateral knees of the patients were used as the control group. Based on the Kellgren-Lawrence classification system, stages 3 and 4 were accepted as the existence of osteoarthritis. Body mass index, the distance to the subchondral joint line, tumor mass volume, the location of the tumor (i.e., femur, tibia, medial condyle, or lateral condyle), age, and sex were also investigated, all of which are factors that can affect the occurrence of osteoarthritis.

Results: Forty-three patients, 24 male (56%) and 19 female (44%), were included in the study. The mean age of the patients was 29.5 ± 10 years, and mean follow up duration was 128.7 months. Tumor localization was the distal femur in 20 patients (46.5%) and the proximal tibia in 23 patients (53.5%). The mean tumor mass volume was 77.84 cm and the distance to the knee joint subchondral line was 3.2 ± 2 mm. According to this scoring system, 14 patients were at stage 0, 10 patients were at stage 1, 10 patients were at stage 2, four patients were at stage 3, and five patients were at stage 4. When we compared osteoarthritis development, the affected knee had a significantly higher rate of osteoarthritis development than the contralateral knee. A univariate analysis demonstrated that age (P = 0.002) and body mass index (P = 0.045) were associated with secondary osteoarthritis. Moreover, multivariate analysis demonstrated that none of the variables were independently associated with secondary osteoarthritis.

Conclusion: Patients with contralateral osteoarthritis had bilateral knee osteoarthritis, indicating that primary osteoarthritis progressed in both knees. Seven of the 43 patients (16.2%) showed secondary osteoarthritis. Although age and body mass index were associated with secondary osteoarthritis in univariate analysis, none of the variables were independently associated with secondary osteoarthritis in the multivariate analysis.