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Single-Bundle Anterior Cruciate Ligament Reconstruction: Restoration of the Native Footprint - A Simple 3D CT Radiographic Evaluation for All Surgeons

      Introduction

      Anatomic ACLR leads to superior outcomes by restoring kinematics, reestablishing stability, minimizing recurrent injuries, and preventing degenerative changes. Surgical technique may play a role in the development and progression of knee OA. The ACL graft footprint position was evaluated following single-bundle, TT ACLR to determine if this technique can restore the native ACL footprint while avoiding potential anteromedial portal complications.

      Methods

      Thirty-nine patients (24males, 15females; age 38.4±9.9years) that underwent single-bundle, TT ACLR by a single surgeon (1999-2015) were included. Radiographic evaluation ≥12months following ACLR included radiographs, MRI, and CT scan. CT scan underwent 3D reconstruction to 0.625mm using the OsiriX program (Pixmeo, Geneva, Switzerland). The ratio of the posteroanterior and proximal-distal position for femoral footprints and medial-lateral and anteroposterior position for tibial tunnels were compared to normative cadaveric values using independent samples t-test (p<0.05, corrected for multiple comparisons).

      Results

      Average femoral posteroanterior footprint position (28.6±4.4%) was not statistically different from normative AM bundle footprint (p=0.0547) but was from normative PL bundle footprint (p=0.0001). Average femoral proximal-distal position (39.8±9.0%) was statistically different from normative AM and PL bundle footprints (p=0.0044, p=0.0001). Average tibial medial-lateral footprint position (47.3±2.0%) was not statistically different from normative AM or PL bundle footprints (p=0.4215 and p=0.0909). Average tibial proximal-distal position (47.9±6.0%) was statistically different from normative AM bundle footprint (p=0.0001) but not from normative PL bundle footprint (p=0.2041).

      Conclusion

      The TT, single-bundle technique for ACLR yields a combined AM/PL bundle restoring anteroposterior and rotatory stability of the knee following ACL injury. These results suggest that the femoral footprint is similar to cadaveric values derived for the AM bundle on the femoral side and the PL bundle on the tibial side. This simple, easy to use program can aid all physicians in determining whether their anteromedial portal or TT technique successfully restores the anatomic ACL footprint.