Reliability of Anatomic Bony Landmark Localization of the ACL Femoral Footprint Using 3D MRI

Abstract

Background: Nonanatomic placement of anterior cruciate ligament (ACL) grafts is a leading cause of ACL graft failure. Three-dimensional (3D) magnetic resonance imaging (MRI) femoral footprint localization could enhance planning for an ACL graft's position. Purpose: To determine the intra- and interobserver reliability of measurements of the ACL femoral footprint position and size obtained from 3D MRI scans. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 41 patients with complete ACL tears were recruited between November 2014 and May 2016. Preoperatively, a coronal-oblique proton-density fast spin echo 3D acquisition of the contralateral uninjured knee was obtained along the plane of the ACL using a 1.5T MRI scanner. ACL footprint parameters were obtained independently by 2 musculoskeletal radiologists (observers A and B). The distal and anterior positions of the center of the footprint were measured relative to the apex of the deep cartilage at the posteromedial aspect of the lateral femoral condyle, and the surface area of the ACL femoral footprint was approximated from multiplanar reformatted images. After 1 month, the measurements were repeated. Intraclass correlation coefficients (ICCs) were calculated to assess for intra- and interobserver reliability. Bland-Altman plots were produced to screen for potential systematic bias in measurement and to calculate limits of agreement. Results: The ICCs for intraobserver reliability of the ACL femoral distal and anterior footprint coordinates were 0.75 and 0.78, respectively, for observer A. For observer B, they were 0.75 and 0.74, respectively. The ICCs for interobserver reliability were 0.75 and 0.85 for the distal and anterior coordinates, respectively. Bland-Altman plots demonstrated no significant systematic bias. For surface area measurements, the intraobserver ICCs were 0.37 and 0.62 for observers A and B, respectively. The interobserver reliability was 0.60. Observer B consistently measured the footprints as slightly larger versus observer A (1.19 ± 0.27 vs 1 ± 0.22 cm2, respectively; P < .001). Conclusion: Locating the center of the anatomic footprint of the ACL with 3D MRI showed substantial intra- and interobserver agreement. Interobserver agreement for the femoral footprint surface area was fair to moderate.

Anterior cruciate ligament femoral footprint is oblong‐ovate, triangular, or two‐tears shaped in healthy young adults: three‐dimensional MRI analysis

“…Earlier studies reported a wider range, ranging from 54 mm 2 to 196.8 mm 2 [8,10,23]. Nonetheless, this study noted that the size of the OO-shaped footprint was similar to previous findings, measuring 14 mm in length and 5 mm in width, which aligns with prior reports indicating a mean size between 12.9 and 17.4 mm in length and 5-9.9 mm in width [5,7,8,14,27,28]. Moreover, the characteristics of the TT-shaped footprint were consistent with earlier descriptions of the double-bundle structure, with the TT-H-shaped footprint corresponding to AMB and the TT-L-shaped footprint aligning with PLB.…”

“…1). The length, width and area of the ACL femoral footprint and the lateral wall of the femoral intercondylar notch (LWFIN) were measured using the planimetric tool of the RadiAnt DICOM Viewer. The location of the ACL femoral footprint centre was assessed using two distinct methods: (1) the distance to the apex of the deep cartilage (ADC) [28] and (2) the coordinates in the BH grid [2, 18]. The ADC was identified as the most superior point on the posteromedial aspect of the articular cartilage of the lateral femoral condyle.…”

“…7. The location of the ACL femoral footprint centre was assessed using two distinct methods: (1) the distance to the apex of the deep cartilage (ADC) [28] and (2) the coordinates in the BH grid [2,18]. The ADC was identified as the most superior point on the posteromedial aspect of the articular cartilage of the lateral femoral condyle.…”

Application of the 3D-MRI on post-operative graft assessment in adolescent patients with ACL reconstruction: A minimal 2-year follow-up

“…Reconstructed three-dimensional MRI (3D-MRI) is a new objective imaging assessment for ALCR (9). The latest study has reported that using 3D-MRI on assessment of the reconstructed ACL showed a substantial intra-and interobserver agreement (10). It has also been shown that 3D-MRI identification of the reconstructed ACL compares favorably and can be used interchangeably with the anatomic identification of cadaveric ACL (11).…”

Compressed Lateral and anteroposterior Anatomical Systematic Sequences «CLASS»: compressed MRI sequences with assessed anatomical femoral and tibial ACL's footprints, a feasibility study

“…Different options have been described in the literature for proper assessment of femoral and tibial ACL‐footprint [12, 19]. Three‐dimensional MRI studies showed its reliability [3, 11, 21, 24, 26]. Research has shown that ACL footprints may present a variable location in different individuals [22], and therefore, their intraoperative identification can be challenging.…”