Summary

This simple, easy to use free, downloadable program can aid all physicians in determining whether their anteromedial or transtibial technique successfully restores the anatomic ACL footprint.

Abstract

Introduction

Anatomic reconstruction of the anterior cruciate ligament (ACL) has been suggested to lead to superior outcomes by restoring knee kinematics, reestablishing anterior and rotatory stability and preventing degenerative changes. Surgical technique may play a role in the development and progression of knee osteoarthritis (OA); the anteromedial (AM) portal has been associated with critically short tunnels and an increased risk of posterior wall blowout, while the transtibial (TT) tunnel technique has been criticized for resulting in too vertical tunnel placement and failing to restore native anatomy which may predispose patients to the development of early knee OA. The footprint position of the ACL graft was evaluated in patients following a single-bundle, transtibial ACLR to determine whether this technique can restore the native ACL footprint.

Methods

Thirty-nine patients (24 males, 15 females; age 38.4±9.9 years) that underwent single-bundle, TT ACLR by a single surgeon (1999-2016) were included. Radiographs, MRI, and CT scan =12months following ACLR were analyzed. CT scan underwent 3D reconstruction to 0.625mm using OsiriX. The ratio of the posteroanterior and proximal distal position for the femoral footprint and medial lateral and anteroposterior position for the tibial tunnel were calculated. Values will be compared to the normative values generated by cadaveric measurement as previously published by Forsythe (2010) using an independent samples t-test with significance set at p<0.05.

Results

Average femoral posteroanterior footprint position was 28.6±4.4 % which was not statistically different than normative AM bundle footprint (p=0.0547) but statistically different compared to normative PL bundle footprint (p=0.0001). Average femoral proximal distal position was 39.8±9.0% which was statistically different than normative AM bundle footprint (p=0.0044) and normative PL bundle footprint (p=0.0001). Average tibial medial lateral footprint position was 47.9± 6.0% which was not statistically different from normative AM bundle (p=0.4215) or PL bundle footprint (p=0.0909). Average tibial anteroposterior position was 47.9 ± 6.0% which was statistically different than normative AM bundle footprint (p=0.0001) but not statistically different from normative PL bundle footprint (p=0.2041).

Discussion

Our transtibial, single-bundle technique for ACLR appears to yield a combined anteromedial and posterolateral bundle matching normative cadaveric values of the AM bundle on the femoral side and the PL bundle on the tibial side restoring both anteroposterior and rotatory stability of the knee with a low recurrence rate of 6.3% in all patients following ACL surgery.