ESTIMATION OF FEMORAL LENGTH FOR INTRAMEDULLARY NAIL USING FOREARM AS REFERENCE

Abstract

Background: goal of our study was to predict the size of intramedullary nail using forearm as reference. Intra-medullary nailing has become favoured treatment for femoral shaft fractures. An implant of the correct size is needed to achieve the desired results. Preoperative templating is useful and well established for trauma and elective surgery to ensure availablity of a suitable implant of correct size preoperatively. Various ways have been described to estimate the nail length. Most commonly used is to x-ray the other limb or directly measure the reamer under x-ray. However these methods involve use of x-rays and information is not well-timed. We describe a simple technique, which can be used to predict the length of femur and therefore have the intra medullary nail of appropriate length available.

METHOD: measurements were taken on 100 volunteers from the tip of olecranon to the tip of little finger and tip of greater trochanter to palpable joint line on the lateral side of the knee. Two observers took the measurements on both sides. We used an ordinary plastic tape measure for ease of use and reproducibility.

RESULTS: statistical analysis revealed a very strong correlation (with pearson correlation factor of 1) between the two lengths. Difference between the two means was 0.16 Mm.

CONCLUSION: forearm reference represents maximum nail length required. It provides a useful method of estimation of femoral length. It can be easily applied in clinical practice with a tape measure alone without resort to x-rays and other expensive and possibly harmful means.