Background and purpose: Locating and measuring the length of the distal femoral canal is a very important stage in reconstructive surgery of anterior and posterior cruciate ligament rupture in knee. Sometimes it is difficult or impossible to measure it in some patients. To resolve this problem, a measuring tool called the Measuring Instrument of the Length of the Femoral Canal (Satkr) was designed and registered in Iranian patent office. The instrument was designed to measure the length of the femoral canal before creating any canal in distal femur (therefore, enabling surgeons to change it if it was not calculated properly).

Materials and methods: In this comparative cross sectional study, a part from Satkr, two other instruments which are commonly used in reconstructive surgery of knee ligaments including a 4.5 graded Reamer and a depth gauge that is the final confirming tool for measuring the length of the canal were applied to 50 patients of both sexes. According to the operating techniques, measures of the length of the canal were separately written and statistical differences were recorded in two-sided way.

Results: Data indicated significant differences between the scores of Reimer, depth gauge and Satkr (P=0.004).

Conclusion: According to this study, Satkr had significantly less errors compared to Reamer. Thus, it can be claimed that the measurements obtained by Satkr are more precise than measurements obtained by other measuring tools.