2023 ISAKOS Biennial Congress ePoster
The Lateral Femoral Notch Sign Decreases in Pediatric Patients Following Anterior Cruciate Ligament Reconstruction
Nicolas Pascual-Leone, BA, Philadelphia, PA UNITED STATES
Danielle E Chipman, BS, New York, NY UNITED STATES
Douglas Mintz, MD, New York, NY UNITED STATES
Frank A. Cordasco, MD, MS, New York, NY UNITED STATES
Peter D. Fabricant, MD, MPH, New York, NY UNITED STATES
Daniel W. Green, MD, MS, New York, NY UNITED STATES
Hospital for Special Surgery, New York, NY, UNITED STATES
FDA Status Not Applicable
Summary
A lateral femoral notch sign (LFNS) may be indicative of an ACL tear. Our findings suggest that following ACL rupture, the pediatric LFNS has the potential to heal, and future studies should aim to further assess the healing pattern of the LFNS with advanced imaging, such as MRI.
ePosters will be available shortly before Congress
Abstract
Objectives:
While magnetic resonance imaging (MRI) is typically used to confirm anterior cruciate ligament (ACL) rupture, certain radiologic findings can be indicative of an ACL tear. A lateral femoral notch sign (LFNS) greater than 1.5 millimeters (mm) is one of these radiologic findings. No study however has focused on understanding the healing pattern of the LFNS in pediatric patients following ACL reconstruction (ACLR). The aim of this study is to determine whether the depth of the LFNS regresses following ACLR. The authors hypothesize that following ACLR, the LFNS will decrease.
Methods
Using the Current Procedural Terminology code 29888 for ACLR, 321 subjects between 5 and 18 years old who underwent ACLR by one of two orthopedic surgeons between 2015 and 2020 were identified. Patients were excluded if they underwent previous ipsilateral knee surgeries or underwent primary ACL repair rather than reconstruction. Patients were also excluded if they did not have any pre-operative lateral knee radiograph. 274 patients were included in the final analysis. LFNS was measured on pre-operative (PreOp) and most recent post-operative (PostOp) radiographs. A comparison cohort of 13 patients with a LFNS less than 1.5 mm matched by age within 1.5 years, sex, and laterality was also collected. Statistical analyses were?performed using?IBM SPSS version 22.?
Results
274 pre-operative radiographs were analyzed for a LFNS depth greater than 1.5 mm. 17 (5.8%) radiographs met these criteria with a median depth of 1.7 mm. The median LFNS depth at most recent follow up and median percent decrease were 1.5 mm and 28%, respectively. Only 2/17 (11.8%) patients demonstrated no change in LFNS depth from PreOp to PostOp imaging. Wilcoxon Signed-Rank test indicated that the PreOp LFNS (mean rank = 8) was significantly greater than the PostOp LFNS (mean rank = 0) (p<0.001). Mann Whitney U tests with cases and the comparison cohort demonstrated no difference in the percent decrease (p = 0.11).
Conclusion
This study sought to understand the resolution of the LFNS depth following initial ACL rupture. At a median of 7.7 months following ACLR, the LFNS depth decreased significantly by 0.6 mm. These findings suggest that following ACL rupture, the pediatric LFNS has the potential to heal. Future studies should aim to further assess the healing pattern of the LFNS with advanced imaging, such as MRI.