THE IMPORTANCE OF TUMOUR VOLUME TO DISTAL FEMORAL VOLUME RATIO IN THE PRESENTATION OF GIANT CELL TUMOURS OF THE DISTAL FEMUR

Abstract

To identify the incidence of a cortical breech on the initial presentation X-rays of patients with distal femoral GCTs, and whether this lead to a higher rate of local recurrence of tumour, a prospective database is kept of all patients seen in the unit. Initial presentation X-rays on 54 patients with distal femroal GCTs were reviewed. The size of the tumour was estimated by measuring the largest dimensions of the tumour (depth, breadth & height). The volume of the distal femur was estimated using the same X-ray and computer programme. The X-rays were then carefully studied for evidence of a cortical breach. The records were also checked for evidence of subsequent locally recurrent disease and subsequent surgery.

X-rays were reviewed on 54 patients (29 male, 25 female), range of 18–72 years. All patients had a biopsy-proven GCT of the distal femur, X-rays (prior to biopsy) were reviewed. 34 (63%) patients with a cortical breech on X-ray. The mean tumour volume: distal femoral volumes (TV:DFV) was statistically greater between those patients with a cortical breach and those without, using ANOVA (p< 0.0001). There were 13 patients with local recurrent disease but no statistical difference in subsequent local recurrence rates between the two patient groups. There was also no statistical differences between the number of operations for those who presented with a cortical breach or without. There was no evidence that more radical surgery was required if a patient presented with a cortical breach.

The risk of cortical breech in patients with GCTs of the distal femur is dependant upon the tumour volume to distal femur volume ratio. If the ratio is above 54% then present with a cortical breech on X-ray is likely (95% confidence interval).There is no evidence those patients with a cortical breach have a higher rate of local recurrence, an increased number of operations or more radical surgery.

Conclusion: The risk of cortical breech in patients with GCTs of the distal femur is dependent upon the tumour volume to distal femur volume ratio.