Reconstructed anterior cruciate ligaments using patellar tendon ligament grafts: diagnostic value of contrast-enhanced MRI in a 2-year follow-up regimen

Abstract

We analyzed prospectively the diagnostic efficacy of contrast-enhanced MRI following anterior cruciate neoligament (ACL) reconstruction. One hundred fifty-six MR examinations were performed 2, 12, 52, 76, and 104 weeks post-operatively on 68 patients with ACL transplants. Sagittal, parasagittal, and coronal images using unenhanced T1- and T2-weighted spinecho sequences, and post-contrast images utilizing T1-weighted spinecho and fat-saturated sequences, were acquired. Results were correlated with those of the pivot shift, Lachman, and a mechanical test. The MR examination criteria included morphological analysis, signal intensity, transplant contrast enhancement, secondary signs (e.g., elongation of normal ligaments), and comparison with clinically standardized test results. Two weeks post-operatively all neoligaments showed homogeneous low signal intensity on T1- and T2-weighted spinecho sequences indistinguishable from that of normal cruciate or patellar ligaments [contrast-to-noise ratio (C/N) on T1: 1.6], with a 9% percentile enhancement. At 12-52 weeks, signal intensity increased (C/N: 6.7), with a mean 50% percentile enhancement. The 1-year follow-up allowed no definite assessment of the neoligament's course. At 76 and 104 weeks, significant decrements in signal intensity (C/N: 3.0) and ligamentous percentile enhancement (25%) occurred. All patients tested displayed stable transplants 2 years post-operatively. Contrast-enhanced MRI allows accurate evaluation of morphology and function up to 3 months postoperatively and 1-2 years following ACL reconstructive surgery.

MRI of double-bundle ACL reconstruction: evaluation of graft findings

“…MRI evaluation of traditional SB ACL graft reconstruction and complications is well established in the literature [18][19][20][21][22][23][24], but there are only a moderate number of publications of DB MRI imaging [17,[25][26][27]34]. According to Casagranda et al, the complications of SB and DB ACL reconstructions are similar [25].…”

“…A preliminary study investigating the T2-weighted SI of DB ACL grafts 1 year after operation suggests that the PL graft SI is increased at that time compared to the AM graft SI [27]. In SB ACL reconstruction the graft SI is increased in both T1-weighted and T2-weighted images during the ligamentization period 3-24 months after surgery [20,28].…”

“…Prior studies have described the appearance and maturation of an intact SB ACL reconstruction graft [20,21] and also the MRI findings of postsurgical complications [18,19,[21][22][23][24]. The most common complications include graft rupture, cystic degeneration of the graft, graft impingement, and arthrofibrosis [18,19,[21][22][23][24].…”

Effects of a Platelet Gel on Early Graft Revascularization after Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized, Double-Blind, Clinical Trial

“…In the literature, we found several trials assessing graft healing after ACL reconstruction using MRI evaluation in humans [29,33] . Few studies correlated the signal intensity of the graft to MRI and corresponding histological findings during early graft healing.…”

“…The result of one measurement was expressed as a signal/noise quotient (SNQ). The vascularization rate was defined as the difference in the SNQ after and before the application of the contrast medium for each ROI, as described by Howell et al [24] and Vogl et al [29] . In other words, the more vascularized the ROI is, the greater the difference in the MRI signal intensity and therefore the greater the difference between the SNQ after and before the application of the contrast medium.…”