A prospective study on predicting local recurrence of giant cell tumour of bone by evaluating preoperative imaging features of the tumour around the knee joint.

Purpose: To evaluate the role of medical imaging in predicting local recurrence of giant cell tumour of bone (GCTB) by assessing the preoperative imaging features of GCTB around the knee.
Methods: Forty-eight consecutive GCTBs in the proximal tibia and distal femur treated with curettage were prospectively enrolled. Patients were grouped in terms of their imaging features on radiography, computed tomography (CT) and magnetic resonance imaging (MRI). All patients were followed up for at least two years after surgery. The association between preoperative imaging features and local recurrence was investigated. Imaging features were retrospectively studied by correlation analysis. The differences between rates were tested by the Chi square and Fisher exact tests; independent factors were determined by multivariate logistic regression analysis.
Results: Cystic change and adjacent soft tissue invasion were associated with a higher rate of local recurrence compared to the negative groups (P < 0.05). Cystic change was identified as an independent risk factor for local recurrence of GCTB (P < 0.05). Expansibility was correlated with the "soap bubble" sign and the fluid-fluid level (P < 0.05); the "soap bubble" sign was correlated with osteosclerosis and the fluid-fluid level (P < 0.05); cortical bone involvement was correlated with adjacent soft tissue invasion (P < 0.05); and cystic change was correlated with the fluid-fluid level (P < 0.05).
Conclusion: Cystic change was an independent risk factor for local recurrence of GCTB. Adjacent soft tissue invasion might indirectly relate to local relapse. A cluster of association relationships between imaging features was revealed.