To evaluate the accuracy of femoral length measurements for ACL reconstruction using the endobutton indicator selection device from outside the knee joint and the transportal endobutton depth gauge.
Methods: 50 cases of primary ACL injuries, both single bundle and double bundle reconstructions were evaluated for their intra operative femoral tunnel lengths by using the Endobuttton indicator selection device from outside the knee joint and the transportal Endobuttton depth gauge and were compared with the post-operative CT femoral tunnel lengths obtained using the Osiri X imaging software.
Results: The mean femoral tunnel lengths measured intraoperatively using the Endobutton selection device (35.68±3.99mm for anteromedial tunnel [AM],) significantly longer than the measurements obtained using the Endobutton depth probe. However, there was no statistically significant difference in the posterolateral tunnel [PL] measurements [37.17±3.83mm for Endobutton selection device and 37.22±3.74 for Endobutton depth probe]. Also the measurements obtained using Endobutton depth probe were closer to the CT measurements and better correlation with the longer CT tunnel wall measurements.
Conclusion: Measurements by both the Endobutton depth probe and the Endobutton selection device are longer than the actual femoral tunnel length for ACL reconstruction. Even though the difference between the mean measurements obtained by the two devices is statistically significant but the actual difference is so minimal that it barely has any effect in the decision making for the selection of the fixed loop device the graft length in ACL reconstruction. Thereby we suggest that the Endobutton Indicator Device is an easy to use and more convenient alternative to the Endobutton depth probe for measuring the femoral tunnel length in ACL reconstruction.