2023 ISAKOS Biennial Congress ePoster
Consistent Anatomic Positioning of Femoral Tunnel Using New Femoral Guide
Tim Spalding, FRCS(Orth), Leamington Spa, Warwickshire UNITED KINGDOM
Rahul Bhattacharyya, MBCHB (Hons), MD (Res), FRCS (Orth), MSc, MRCS, Glasgow UNITED KINGDOM
Nuffield Health Warwick, Leamington Spa, Warwickshire, UNITED KINGDOM
FDA Status Cleared
Summary
3D CT scan evaluation of femoral tunnel position prepared using new anatomic femoral guide shows consistent location in AM bundle location
ePosters will be available shortly before Congress
Abstract
Introduction. Appropriate positioning of the femoral tunnel in ACL reconstruction is vitally important. Whilst the exact position is still unclear, consistent location within the footprint of the ACL attachment is universally agreed. Location of the centre, the AM and PL bundles of the ACL have been described using the Bernard-Hertel grid allowing evaluation of surgery and planning for revision reconstruction. The aim of this study was to evaluate tunnel position when created using a new femoral aiming guide.
Methods. The femoral tunnel was created using a new femoral guide inserted through an accessory low anteromedial portal. The offset hook of the guide was placed over the proximal aspect of the notch and the knee bent to hyperflexion (7mm offset guide for 9/10mm grafts and 5mm offset for 7/8mm grafts). The crescent shaped base of the guide helped position the guide firmly on the femur prior to drilling a spade tip guide wire.
Tunnel position was assessed on CT with 3D reconstruction, manipulated to remove the medial half of the femur and positioned in a true lateral orientation. The centre of the femoral tunnel was identified using a circle and central dot, after which the Bernard-Hertel grid was superimposed allowing measurement of the tunnel with coordinates expressed as percentages from proximal to anterior (PA) and proximal to distal (PD).
Results
19 consecutive patients (11 male and 10 right knees, mean age 30.6 range 15- 55) were evaluated. 5 had 10mm bone block patella tendon grafts, or large tibialis allograft, drilled using the 7mm offset guide and 16 had 4 or 5 strand hamstrings with mean graft diameter of 8.5mm, drilled using the 5mm offset guide.
CT analysis showed that all grafts were centred within the footprint of the ACL with a mean position of 25% PA and 20% PD. Grouping for position was tight and the tunnel positions for the four patients with larger 10mm grafts were more distal and anterior, allowing the bone block and graft to be positioned anatomically.
Conclusion
The guide provided accurate and reproducible positioning of the femoral tunnel within the antero-medial bundle region of the ACL attachment. This can help low volume surgeons reliably and repeatedly achieve anatomic femoral tunnel positioning. When using the larger guide, surgeons should be aware this is best suited to patella tendon grafts.