Importance of femoral tunnel placement in double-bundle posterior cruciate ligament reconstruction: biomechanical analysis using a robotic/universal force-moment sensor testing system.

BACKGROUND

Previous studies have identified the femoral attachment of the posterior cruciate ligament fibers as one of the primary determinants of fiber tension behavior. In addition, a double-bundle posterior cruciate ligament reconstruction has been shown to restore the intact knee kinematics more closely than does a single-bundle reconstruction.

HYPOTHESIS

An anterior tunnel position in double-bundle posterior cruciate ligament reconstruction restores the biomechanics of the normal knee more closely than does a posterior tunnel position.

STUDY DESIGN

Controlled laboratory study.

METHODS

Kinematics and in situ forces of human knees after double-bundle posterior cruciate ligament reconstruction with 2 different femoral tunnel positions (anterior vs posterior) were evaluated using a robotic/universal force-moment sensor testing system. Within the same specimen, the resulting knee kinematics and in situ forces were compared. For statistical analysis, 2-way analysis of variance repeated measures were performed.

RESULTS

The femoral tunnel position of the double-bundle hamstring graft had significant effect on the resulting posterior tibial displacement and in situ forces of the hamstring grafts. The anterior femoral tunnel position provided significantly less posterior tibial translation than did the posterior tunnel position. There was a tendency toward higher in situ forces of grafts fixed in the anterior tunnel when compared to the posterior position, but this difference was statistically not significant.

CONCLUSION

An anterior position of the bone tunnels in double-bundle posterior cruciate ligament reconstruction restores the normal knee kinematics more closely than does a posterior position of the tunnels.

CLINICAL RELEVANCE

In double-bundle posterior cruciate ligament reconstruction, posterior placement of the tunnel should be avoided.