Poster 332: Short Socket Anterior Cruciate Ligament Reconstruction Can Decrease Bone Tunnel Widening- A Quantitative MRI Imaging Analysis on Graft Maturation and Tunnel Dimensions

Objectives: Tunnel widening can occur following ACL reconstruction (ACL-R). Tunnel widening can be challenging when faced with revision and can be an indication of poor graft/tunnel healing. In this study, we aim to focus on the effect of bone tunnel length on ACL graft healing. We hypothesized that shortening the femoral and tibial bone sockets during all-inside ACL-R (without an interference screw and with increased contact between the graft and the bottom of the socket) can improve graft maturation and decrease bone tunnel widening. The objective of this study is to compare the clinical outcomes, graft maturation and post-operative bone tunnel widening between all-inside ACL-R with short bone sockets and anteromedial portal ACL-R. Methods: We prospectively evaluated patients who underwent ACL-R with a hamstring autograft at our institution from 2021 to 2023. Surgical reconstruction was performed by one of three fellowship-trained sports medicine orthopedic surgeons. In the all-inside ACL-R with short socket (Short socket group), the femoral and tibial sockets were drilled using an outside-in retroreaming technique for a depth of 10- and 15-mm socket, respectively. The graft was passed and fixed with suspensory fixation on the femoral side (Infinity Femoral Adjustable Loop Button, CONMED, Largo, FL). It was then tensioned with the knee at 30 degrees and end button fixation was used on the tibial side (Infinity Standard Tibial Button, CONMED, Largo, FL). In the ACL-R with normal tunnel (Normal socket group), the femoral tunnel was created using a reamer through the anteromedial portal that is 20 mm deep and a full tibial tunnel created using outside in drilling. The graft was fixed with suspensory fixation on the femoral side (RIGIDLOOP, Depuy Synthes, Raynham, MA or Ultrabutton Adjustable Fixation Device, Smith & Nephew, Watford, England, UK) and with a sheath and interference screw on the tibial side (Intra-Fix, Depuy Synthes, Raynham, MA). To assess patients reported outcome (PRO) score, International Knee Documentation Committee (IKDC) score, Marx activity scale and Knee Osteoarthritis and Injury Outcome Score (KOOS) were completed at 6 and 12 months follow up. Postoperative 3T magnetic resonance (MR) imaging was acquired 6 and 12 months after surgery. A 3D combined T1ρ/T2 MAPSS sequence and a high-resolution 3D fast spin-echo sequence (CUBE) were obtained in the sagittal plane. Measurement of tunnel diameter and tunnel cross-sectional area (CSA) were