ASSESSING LEG LENGTH DISCREPANCY AFTER FEMORAL FRACTURE: CLINICAL EXAMINATION OR COMPUTED TOMOGRAPHY?

Abstract

Femoral shaft fractures treated with intramedullary nailing often heal with a leg length discrepancy (LLD). LLD is commonly evaluated by clinical examination and computed tomography (CT) scanogram. We assessed the correlation between these two techniques of calculating LLD. We reviewed 35 skeletally mature patients who sustained a femoral shaft fracture between January 1997 and December 1999. Leg length was measured clinically with direct measurement and a block test. Each patient was asked whether they felt they walked with a limp and whether they felt they had a leg length discrepancy. Each patient underwent a CT scanogram to measure femoral and total leg length. The correlation between clinical examination and scanogram was analysed using the Pearson Product Moment Correlation. Of the 35 patients, 15 patients (43%) had a measurable LLD. There was a positive correlation between direct leg length measurement and the block test (P = 0.003), and between the block test and patient perception of limp and LLD. CT scanogram was performed on 29/35 patients. There was no correlation between CT scanogram and clinical measurement of leg length or between CT scanogram and patient perception of LLD or limp. Leg length discrepancy commonly occurs following treatment of femoral shaft fractures. We found that there was a strong correlation between direct leg length measurement and the block test, and between both methods of clinical leg length measurement and patient perception of a limp or LLD. Our study found no correlation between CT scanogram and clinical leg length measurement or patient perception of limp or LLD. Our study shows that physical examination (direct measurement and the block test) is more reliable and clinically relevant than CT scanogram measurement in the assessment of LLD after femoral fracture.