Morphometric analysis and functional correlation of tibial and femoral footprints in anatomical and single bundle reconstructions of the anterior cruciate ligament of the knee.

INTRODUCTION

The anterior cruciate ligament (ACL) is composed of an infinite number of fibers whose individual anatomical and biomechanical features have been well defined. Although numerous biomechanical studies have shown that reconstruction that is as anatomical as possible results in better control of rotational laxity, very few studies have investigated the surface area of tibial and femoral insertion sites in these reconstructions. The aim of this study was to compare the surface areas of tibial and femoral insertion sites in single and double bundle reconstructions and correlate these findings with the isometry profile obtained. Our hypothesis was that double bundle (DB) reconstruction results in better filling of the native ACL footprint thus increasing the biomechanical value of available graft tissue.

PATIENTS AND METHODS

Forty-six patients underwent computer navigated ACL using hamstring tendons: 23 underwent single bundle (SB) and 23 DB reconstruction. The Praxim navigation station equipped with ACL logics software made it possible to digitize insertion site footprints, register perioperative data for graft position as well as anteroposterior and rotational laxities and pivot shift.

RESULTS

There was a statistically significant difference between the two groups for tibial and femoral insertion site surface areas: 71 mm(2) ± 17 (SB) versus 99.9 mm(2) ± 30 (DB) for the tibia, 67 ± 11 mm(2) (SB) versus 96.9 mm(2) ± 28 (DB) for the femur. Isometry profiles showed that anisometry was favorable in all cases: 2.5 mm ± 2 for SB; 2.9 mm ± 2 for the anteromedial bundle (AMB) with DB and 9.6 mm ± 3.7 for the posterolateral bundle. When both groups were combined, there was a statistically significant correlation between the size of tibial insertion surface area and anteroposterior and rotational laxity.

DISCUSSION

This study confirms that better filling of native ACL footprint surface areas results in better control of anteroposterior laxity.

LEVEL OF EVIDENCE

Level IV.