Development of MRI-defined Structural Tissue Damage after Anterior Cruciate Ligament Injury over 5 Years: The KANON Study
Frank W. Roemer, Stefan Lohmander, Martin Englund, Ali Guermazi, Anna Åkesson, R. Frobell
Abstract
Background MRI is used to evaluate structural joint changes after anterior cruciate ligament (ACL) injury, but no long-term data are available for comparing different treatment approaches. Purpose To describe structural joint damage with MRI over a 5-year period in the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) study and to compare frequencies of such tissue damage for a nonsurgical versus a surgical treatment strategy. Materials and Methods In this secondary analysis of a prospective trial (ISRCTN 84752559), 119 participants with an acute ACL injury were evaluated. Participants were enrolled from 2002 through 2006, the 2-year follow-up started in 2008, and the 5-year follow-up started in 2011. A 1.5-T MRI examination was performed at baseline and at 2- and 5-year follow-up. MRI scans were read according to a validated scoring instrument. Kruskal-Wallis tests were used to assess whether the frequencies of structural damage differed between the three as-treated groups. Results Of 119 participants (mean age, 26 years ± 5 [standard deviation]), 91 men were evaluated. At 2- and 5-year follow-up, respectively, 13% (15 of 117) and 13% (15 of 115) of knees showed incident cartilage damage in the medial tibiofemoral joint, 11% (13 of 117) and 17% (20 of 115) of knees showed incident cartilage damage in the lateral tibiofemoral joint, and 4% (five of 117) and 8% (nine of 115) of knees showed incident cartilage damage in the patellofemoral joint. Osteophyte development was seen in 23% (27 of 117) and 29% (33 of 115) of knees in the medial tibiofemoral joint, in 36% (42 of 117) and 43% (49 of 115) of knees in the lateral tibiofemoral joint, and in 35% (41 of 117) and 37% (42 of 115) of knees in the patellofemoral joint. No major differences between the groups were found for incident or worsening cartilage damage, bone marrow lesions, and osteophytes at 2 or 5 years. The rehabilitation-alone group showed less Hoffa-synovitis at 2 (P = .02) and 5 (P = .008) years. Conclusion Young adults with anterior cruciate ligament injury showed no major difference in frequency of structural tissue damage on MRI scans at 2 and 5 years regardless of treatment. However, the rehabilitation-alone group had less inflammation at 2 and 5 years. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Andreisek in this issue.