CLASS-MRI validates patient-specific ACL footprints across variable fluoroscopic C-arm positioning: A cadaveric study

Area of Science:

• Orthopedic Surgery
• Radiology
• Anatomy

Background:

• Accurate identification of anterior cruciate ligament (ACL) footprints (FPs) is crucial for successful anatomical reconstruction.
• Current methods may lack precision, necessitating improved techniques for preoperative planning and intraoperative guidance.

Purpose of the Study:

• To evaluate the accuracy of the Compressed Lateral and Anteroposterior Anatomical Systematic Sequences (CLASS) method for identifying femoral and tibial ACL FPs compared to anatomical dissection.
• To assess the correlation between planned CLASS (pCLASS) and intraoperative fluoroscopy.
• To determine the impact of C-arm positioning on CLASS accuracy.

Main Methods:

• Ten cadaveric knees underwent MRI scans before and after dissection.
• Anatomical CLASS (aCLASS) was created from dissected knee MRI with marked FPs.
• Preoperative planning generated planned CLASS (pCLASS) from native knee MRI.
• Fluoroscopic images were obtained with contralateral and ipsilateral C-arm positioning.
• Statistical analyses included Friedman test, ANOVA, and paired t tests.

Main Results:

• No significant differences were observed in femoral or tibial FP localization between aCLASS, pCLASS, and fluoroscopic measurements.
• pCLASS showed no significant difference compared to both ipsilateral and contralateral fluoroscopic positions.
• C-arm positioning did not significantly affect FP identification accuracy.

Conclusions:

• The CLASS method provides accurate and reliable identification of ACL FPs, comparable to anatomical references.
• CLASS is a validated, patient-specific tool that bridges preoperative planning (MRI) and intraoperative execution (fluoroscopy).
• This technique standardizes ACL reconstruction, enhancing consistency across different surgical settings and surgeon experience levels.