2023 ISAKOS Biennial Congress ePoster
Factors Associated with Tunnel Widening After ACL Reconstruction
Garrett Kearney, Resident/Fellow, Concord, New Hampshire UNITED STATES
Maxwell Mckay, Bachelors Degree, Lynnfield, MA UNITED STATES
Peter Asnis, MD, Boston, MA UNITED STATES
Lars C Richardson, MD, Boston, MA UNITED STATES
Mark David Price, MD, Wellesley, MA UNITED STATES
Miho J. Tanaka, MD, PhD, Boston, MA UNITED STATES
Massachusetts General Hospital – Department of Orthopaedic Surgery; Harvard Medical School, Boston, MA, UNITED STATES
FDA Status Not Applicable
Summary
Knees with failed ACL grafts had greater tunnel widening than intact knees, and that the patterns and location of tunnel widening differed by sex and graft type.
ePosters will be available shortly before Congress
Abstract
Tunnel widening after ACL reconstruction has been described to have both biological and mechanical causes. However, the exact etiology and mechanism of this process is unknown. The objective of this study was to describe differences in patterns of tunnel widening when comparing intact and failed ACL grafts and the factors associated with these changes.
Patients with primary ACL reconstruction with BTB autograft or allograft and biocomposite screw fixation who were subsequently evaluated for graft failure or contralateral knee injury were included in this study. Operative notes were reviewed to determine the femoral and tibial tunnel sizes created at the time of index surgery. Radiographs at the time of follow up were reviewed, and tunnel sizes were measured at the largest diameter on the AP views. Tunnel widening was calculated based on the changes in tunnel size and compared between cases with failed vs intact ACL grafts. Subgroup analysis by sex and graft type were performed. Age and time to followup were assessed for their influence on tunnel widening.
121 knees (59F, 62M, mean age 28.7+/-12.1y) were included in this study, with mean followup at 3.5+/-2.7 years. 87 failed ACL grafts were identified and compared with 34 intact knees. 68.6% had undergone reconstruction with BTB autograft, while the remainder had BTB allograft. In the intact group, femoral tunnel and tibial tunnel widening were 0.3+/-1.9mm (3.2+/-19.9%) and 0.9+/-1.8mm (9.0+/-18.4%) respectively. Femoral tunnel widening was greater in knees with failed ACL grafts than intact knees by 1.3+/-1.5mm (p<0.001) whereas tibial tunnel widening was comparable. In males who underwent autograft ACL reconstruction, there were no significant differences in tunnel widening between failed and intact grafts. Females with failed autograft had 1.2mm (12%) greater femoral tunnel widening with no significant differences in tibial tunnel widening when compared to the intact group. In knees that underwent allograft ACL reconstruction, males had 3.6mm (36.5%) greater femoral tunnel widening in failed ACL allograft compared to intact allograft knees. In females with failed ACL allograft, femoral tunnel widening was 3.0mm (31.1%) (p=0.005) greater and tibial tunnel widening was 2.1mm greater (20.4%) (p=0.011) than the intact allograft group. No significant association was noted between tunnel widening and age or time to followup.
Our study identified that knees with failed ACL grafts had greater tunnel widening than intact knees, and that the patterns and location of tunnel widening differed by sex and graft type. As tunnel widening can complicate revision surgery, further studies are needed to better understand the surgical and patient-related factors that can contribute to these differences following ACL reconstruction.