Analysis of the articular cartilage T_1ρ and T₂ relaxation times changes after ACL reconstruction in injured and contralateral knees and relationships with bone shape

Abstract

The objectives of this study were twofold: (1) to evaluate the longitudinal change in cartilage T and T 6- and 12-months after ACL reconstruction (ACLR) in both reconstructed and intact contralateral knees with the aim of validating the role of the contralateral knee as an internal control in longitudinal studies; (2) to explore relationships between bone shape at the time of injury and the progression of T and T over 12-months after ACLR. T and T cartilage relaxation times and 3D MRI-based statistical shape modeling (SSM) of tibia and femur were computed for both knees of forty ACL-injured patients and 15 healthy controls. ACL subjects were scanned 8.4 ± 6.4 weeks after injury (2.4 ± 3.7 weeks prior to ACLR), 6- and 12-months after ACLR. Longitudinal changes in T and T values were assessed using linear mixed model, and partial correlation coefficients were calculated between bone shape and longitudinal changes in T and T values. Significant longitudinal increases in T and T values were observed in reconstructed and contralateral knees 6-months after ACLR. Tibial bone shape features, associated with the medial plateau height and width, were observed to be correlated with cartilage T and T progression in reconstructed knees. Our results suggest that caution should be used in considering contralateral knee as internal controls in longitudinal ACL studies and 3D MRI-based-SSM might serve as an imaging biomarker for the early stratification of patients at risk for developing post-traumatic accelerated cartilage degeneration and potentially osteoarthritis after ACL tear. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:707-717, 2017.

Quantitative imaging of bone–cartilage interactions in ACL-injured patients with PET–MRI

“…The diffuse nature of 18 F-NaF uptake may be due to changes in joint loading, knee rehabilitation or other factors that affect the whole-joint. Diffuse increases in cartilage T 2 and T 1ρ relaxation times have also been observed after ACL tears 23 . High uptake is also often seen surrounding the ACL graft sites, likely as a result from the ACL reconstruction surgery.…”

“…Additionally, this study used the contralateral knee as a control instead of age-matched healthy subjects. Other studies have shown that following ACL injury, the contralateral knee may also show changes due to changes in loading, knee biomechanics, or other factors 23 . However, we felt that in this study, the contralateral knee serves as the ideal control as it minimizes inter-subject variation; in particular, that intra-subject tracer distribution would be equivalent to both knees for comparison of PET SUV.…”

Study of the interactions between proximal femur 3d bone shape, cartilage health, and biomechanics in patients with hip Osteoarthritis

“…All the segmentations underwent a strict protocol of quality control and a single user (GI) manually adjusted the bone segmentation in case of failure of the automatic procedure. 3D-SSM was performed as previously described and evaluated [35, 36]. …”

Principal component analysis-T1ρ voxel based relaxometry of the articular cartilage: a comparison of biochemical patterns in osteoarthritis and anterior cruciate ligament subjects

“…Elevations in this lateral region have also been observed as predictors of the changes in patientreported outcomes 12 months after reconstruction (16). Longitudinal T 1ρ progression in both injured and contralateral knees has been observed as soon as 6 months after ACL reconstruction, specifically in medial and lateral femur and femoral trochlea compartments (17).…”