Patient specific instrumentation in ACL reconstruction: a proof-of-concept cadaver experiment assessing drilling accuracy when using 3D printed guides

Introduction: Accurate positioning of the femoral tunnel in ACL reconstruction is of the utmost importance to reduce the risk of graft failure. Limited visibility during arthroscopy and a wide anatomical variance attribute to femoral tunnel malposition using conventional surgical techniques. The purpose of this study was to determine whether a patient specific 3D printed surgical guide allows for in vitro femoral tunnel positioning within 2 mm of the planned tunnel position. 

Materials and Methods: A patient specific guide for femoral tunnel positioning in ACL reconstruction was created for four human cadaveric knee specimens based on routine clinical MRI data. Fitting properties were judged by two orthopedic surgeons. MRI scanning was performed both pre- and post-procedure. The planned tunnel endpoint was compared to the actual drilled femoral tunnel. 

Results: This patient specific 3D printed guide showed a mean deviation of 5.0 mm from the center of the planned femoral ACL origin. 

Conclusion: In search to improve accuracy and consistency of femoral tunnel positioning in ACL reconstruction, the use of a patient specific 3D printed surgical guide is a viable option to explore further. The results are comparable to those of conventional techniques; however, further design improvements are necessary to improve accuracy and enhance reproducibility.