Objective: Rupture of the anterior cruciate ligament (ACL) increases the risk of developing osteoarthritis (OA). Delayed Gadolinium enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) investigates cartilage integrity through T1-analysis after intravenous contrast injection. A high dGEMRIC index represents good cartilage quality. The main purpose of this prospective cohort study was to investigate the prognostic value of the dGEMRIC index regarding future knee OA.
Method: 31 patients with ACL injury (mean age 27 ± 6.7 (±SD) years, 19 males) were examined after 2 years with 1.5T dGEMRIC of femoral cartilage. Re-examination 14 years post-injury included weight-bearing knee radiographs, Lysholm and Knee Osteoarthritis Outcome Score (KOOS).
Results: At the 14-year follow up radiographic OA (ROA) was present in 68% and OA symptoms (SOA) in 42% of the injured knees. The dGEMRIC index of the medial compartment was lower in knees that developed medial ROA, 325 ± 68 (ms±SD) vs 376 ± 47 (51 (7-94)) (difference of means (95% confidence interval (CI))), in patients that developed symptomatic OA (SOA), 327 ± 61 vs 399 ± 42 (52 (11-93)), and poor knee function 337 ± 54 vs 381 ± 52 (48 (7-89)) compared to those that did not develop ROA, SOA or poor function. The dGEMRIC index correlated negatively with the OARSI osteophyte score in medial (r = -0.44, P = 0.01) and lateral (r = -0.38, P = 0.03) compartments.
Conclusion: The associations between a low dGEMRIC index and future ROA, as well as SOA, are in agreement with previous studies and indicate that dGEMRIC has a prognostic value for future knee OA.
Keywords: Anterior cruciate ligament injury; Compositional MRI; GAG; Osteoarthritis; Post traumatic osteoarthritis; dGEMRIC.
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