Complications of anterior cruciate ligament reconstruction: MR imaging

Abstract

Arthroscopic reconstruction of the anterior cruciate ligament (ACL) using autografts or allografts is being performed with increasing frequency, particularly in young athletes. Although the procedure is generally well tolerated, with good success rates, early and late complications have been documented. As clinical manifestations of graft complications are often non-specific and plain radiographs cannot directly visualize the graft and the adjacent soft tissues, MR imaging has a definite role in the diagnosis of complications after ACL reconstruction and may direct subsequent therapeutic management. Our purpose is to review the normal MR imaging of the ACL graft and present the MR imaging findings of a wide spectrum of complications after ACL reconstruction, such as graft impingement, graft rupture, cystic degeneration of the graft, postoperative infection of the knee, diffuse and localized (i.e., cyclops lesion) arthrofibrosis, and associated donor site abnormalities. Awareness of the MR imaging findings of complications as well as the normal appearances of the normal ACL graft is essential for correct interpretation.

Infections in Anterior Cruciate Ligament Reconstruction

“…34 Findings on imaging can include joint effusion, synovitis, bone erosions, edema of adjacent soft tissues and bone marrow, sinus tracts, and soft tissue abscesses. 52 …”

Cyclops lesions detected by MRI are frequent findings after ACL surgical reconstruction but do not impact clinical outcome over 2 years

“…A frequent complication is a clinical syndrome defined as loss of knee extension associated with pain at terminal extension, which usually occurs within the first 2 years after surgery [3–7]. Main causes of the mechanical block preventing full extension are graft impingement and cyclops lesions [5, 6, 8, 9]. Cyclops lesions are focal nodules of fibrous tissue located in the intercondylar notch, tightly connected with the reconstructed graft and mostly located anterior to it [10].…”

Cyclops lesions are associated with altered gait patterns and medial knee joint cartilage degeneration at 1 year after ACL‐reconstruction

“…14 Besides graft impingement, another cause of reduced range of motion after ACLR is the presence of cyclops lesions. [15][16][17][18][19][20][21][22] Cyclops lesions are focal nodules of fibrocartilaginous tissue that are tightly connected to the anterior portion of the ACL graft, most frequently located within the intercondylar notch 19,22 and occur in approximately 10-25% of ACLR patients. [23][24][25] The formation of cyclops lesions may be due to repetitive microtrauma to the ACL graft 15,20 or by debris that is present within the knee joint from the drilling and preparation of the tibial tunnel during ACLR.…”

“…15,26 However, the presence of cyclops lesions may cause altered knee joint mechanics in asymptomatic ACLR patients as well. 15,16,22 Despite the interest in the presence/development of cyclops lesions after ACLR, [15][16][17][18][19][20][21][22] the effect of cyclops lesions on lower extremity mechanics and the onset or progression of knee cartilage degeneration in ACLR patients has yet to be investigated. Therefore, the purpose of the current study was to assess the association between knee joint mechanics and medial tibiofemoral cartilage composition in ACLR patients with and without cyclops lesions.…”