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Musculoskeletal Imaging

E3232. Anterior Cruciate Ligament Graft Reconstruction: A Comprehensive Review of Related Complications

Gunduru M,  Abdelhadi S,  Daruwalla V,  Mohandas A,  Al-Hihi M. Detroit Medical Center, Wayne State University, Detroit, MI

Address correspondence to M. Gunduru (mgunduru@dmc.org)

Background Information: Anterior cruciate ligament (ACL) is one of the most frequently injured ligaments of the knee, resulting in instability and functional impairment. Graft reconstruction of the ACL has become the standard of treatment to prevent joint instability and further damage to the articular cartilage and menisci. MRI is an important and reliable modality for the assessment of ACL reconstruction outcome. The purpose of this educational exhibit is to provide a comprehensive review of the normal MRI findings of the ACL graft in various reconstruction procedures and graft-related complications.

Educational Goals/Teaching Points: It is important to know the normal MRI appearance of an ACL graft in different types of reconstruction procedures and recognize the characteristic MRI findings of ACL graft-related complications.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: ACL is an intraarticular, extrasynovial structure. It originates from the medial and anterior aspect of the tibial plateau and runs superiorly, laterally, and posteriorly towards its insertion on the lateral femoral condyle. Fast-spin-echo sequences with or without fat suppression are optimal for the visualization of the ACL. The normal ACL should has a taut, low signal intensity with continuous fibers in all planes and sequences. The normal ACL graft has a uniform low signal intensity on T1- and T2-weighted images during first 3 months after surgery. Later, there is increased intrasubstance signal on T1- and T2-weighted sequences due to proliferation of the blood vessels and synovium. Eventually, the ACL graft will resume a normal uniform low signal intensity. There are various ACL graft reconstruction-related complications, such as partial or complete graft tear, arthrofibrosis, roof impingement, tunnel cysts, intraarticular bodies, iliotibial band friction syndrome, hardware loosening or infection, and harvest site and vascular complications, which are essentially evaluated by MRI.

Conclusion: ACL reconstruction is one of the most commonly performed sports medicine procedure in the United States, with approximately 100,000 procedures performed each year. As the clinical evaluation of ACL reconstruction is difficult, MRI has become the preferred modality in the assessment of ACL graft integrity. As such, it is imperative that radiologists are familiar with different reconstruction surgeries and their associated common complications.