Comparison of T1rho relaxation times between ACL-reconstructed knees and contralateral uninjured knees.
OBJECTIVE
The goal of this study is to compare the cartilage of anterior cruciate ligament (ACL)-reconstructed and uninjured contralateral knees using T 1ρ MRI 12-16 months after ACL reconstructions.


METHODS
Eighteen patients with ACL-reconstructed knees (10 women, 8 men, mean age = 38.3 ± 7.8 years) were studied using 3T MRI. Injured and contralateral knee MR studies were acquired 12-16 months post-operatively. Cartilage sub-compartment T 1ρ values of each injured knee were compared with the contralateral knee's values. Subgroup analysis of sub-compartment T 1ρ values in both knees was performed between patients with and without meniscal tears at the time of ACL reconstruction using a paired Student's t test.


RESULTS
In ACL-injured knees, the T 1ρ values of the medial tibia (MT) and medial femoral condyle (MFC) were significantly elevated at 12-16 months follow-up compared to contralateral knees. Patients with a medial meniscal tear had higher MFC and MT T 1ρ values compared to respective regions in contralateral knees. Patients with lateral meniscal tears had higher lateral femoral condyle and LT T 1ρ values compared to respective regions in contralateral knees. There were no differences between the injured and contralateral knees of patients without meniscal tears.


CONCLUSIONS
T 1ρ MRI can detect significant changes in the medial compartments' cartilage matrix of ACL-reconstructed knees at 1 year post-operatively compared to contralateral knees. The presence of a meniscal tear at the time of ACL reconstruction is a risk factor for cartilage matrix degeneration in the femorotibial compartments on the same side as the meniscal tear.
Department of Orthopaedic Surgery, San Francisco School of Medicine, University of California, 500 Parnassus Ave, MU320W, San Francisco, CA, 94143, USA.
Alexander A
AA
Theologis
Bryan
B
Haughom
Fei
F
Liang
Yu
Y
Zhang
Sharmila
S
Majumdar
Thomas M
TM
Link
C Benjamin
CB
Ma
Xiaojuan
X
Li
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D002358:Cartilage, Articular / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000473:pathology / Q000601:surgery*; D007719:Knee Joint / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome