J Korean Radiol Soc.  1998 Jan;38(1):151-157. 10.3348/jkrs.1998.38.1.151.

Natural Evolution of Grafted Anterior Cruciate Ligament of the Knee: Prospective Follow-up MR Studies

• Park DW
• Cho JH
• Ihn YK
• Shim YW
• Suh JS
• Min BH
• Suh JH

• KMID: 2103067
• DOI: http://doi.org/10.3348/jkrs.1998.38.1.151

Abstract

PURPOSE: To described the MR findings in the periodic changes of the size and signal intensity ofreconstructed anterior cruciate ligament (ACL) of the knee and the efficacy of oblique axial imaging in patientswho underwent arthroscopic ACL reconstruction using autogenous patellar tendon.
MATERIALS AND METHODS
Twenty-onepatients who had undergone ACL reconstruction were evaluated by follow-up MRI at postoperative 1 week, 1, 2, 3 and6 months, and 1 year, Conventional Fast-Spin-Echo (FSE) sagittal and coronal images and oblique axial images(proton density and T2-WI; VEMP TR/TE, 2000/20/70) were obtained perpendicular to the ligament, and using an ROIcurve in the intra-articular area, periodic changes in the cross-sectional area were evaluated by proton densityimaging and signal intensity by T2WI imaging. Cross-sectional morphology was categorized as either smooth, andround or notch-shaped and periodic changes in configuration were observed. In three cases, we evaluated the retearof reconstructed ACL by comparing the oblique axizl image obtained by conventional sagittal and coronal imaging.
RESULTS
The cross-sectional area and signal intensity of grafted ACL increased significantly (p<0.05) after 3months and at 1 year, respectively. Cross-sectional morphology was smooth and round in 86% of cases, and notchedin 14%, and during follow-up MR studies, no periodic changes were seen. Notch-shaped ACL and decreased perigraftsignal intensity, as seen on sagittal images, could lead to a misdiagnosis of partial tear ; on oblique axialimages, ACL and perigraft signal intensity were found to be normal.
CONCLUSION
During the natural evolution ofgrafted ACL, cross-sectional area and signal intensity increased significantly after 3 months and at 1 year,respectively ; on follow-up MR studies, cross-sectional morphology did not change, however. Oblique axial imagingprovides important information for evaluating whether the reconstructed ACL is torn or not.

Keyword

Knee, MR; Knee, ligaments, menisci and cartilage; Knee, injuries

MeSH Terms

Anterior Cruciate Ligament*
Cross-Sectional Studies
Diagnostic Errors
Follow-Up Studies*
Knee*
Ligaments
Magnetic Resonance Imaging
Patellar Ligament
Prospective Studies*
Protons
Transplants*
Protons