Prediction of saphenofemoral junction incompetence by measurement of great saphenous vein size at the level of femoral condyle

Introduction: Doppler ultrasonography (USG) is the primary modality for diagnosis of superficial venous reflux caused by incompetence of venous valves of the great saphenous vein (GSV) and usually associated with competence of saphenofemoral junction (SFJ). This study is done to know the cutoff value in size of GSV that safely predicts this junction incompetence. Methods: All varicose vein patients during the study period of January–December 2016 were included in the study. The cases underwent Doppler USG of GSV using Siemens Acuson P500 to identify GSV. The diameter of GSV was measured at the level of femoral condyle in standing position and these were compared with SFJ incompetence. Contralateral limbs which were apparently normal were taken as control limbs if there is no evidence of reflux in SFJ. Results: There were 147 patients with 16 cases (9.81%) where bilateral limb was involved making total cases as 163 limbs and controls as 131 limbs. The mean GSV diameter in disease group was 6.05 mm and in control group was 3.19 mm with P < 0.05. Receiver operating characteristic (ROC) curve of size of GSV at the level of knee and prediction of SFJ incompetence had the ideal curve depicting use of some cutoff value. The point with both best sensitivity and specificity lied on 4.95 mm with sensitivity of 82% and specificity of 83%. Conclusion: We recommend 5 mm as the cutoff value for diameter of GSV at the level of femoral condyle which successfully predicts SFJ incompetence