Groupings of coexisting MRI lesions of the tibiofemoral and patellofemoral joints were linked to the risk of subsequent radiographic osteoarthritis, investigators reported. Their analysis of data from the prospective, observational MOST study was published online Sept. 28 in Arthritis and Rheumatism.
“The magnitude of lesions such as cartilage damage and coexisting meniscal damage appear to be the main distinction between the subgroups,” said Dr. Jingbo Niu of Boston University and her associates. Several studies have linked individual MRI lesions with incident knee OA, but patterns of coexisting lesions more accurately reflect real-world injuries, such as anterior cruciate ligament tears, which tend to affect more than one knee structure, the investigators noted.
Dr. Jingbo Niu
Because directly comparing lesions in a multivariate model does not account for chronology, the investigators used latent class analysis to identify subgroups of coexisting MRI lesions of the tibiofemoral and patellofemoral joints, such as cartilage damage, meniscal tear, meniscal extrusion, synovitis, and effusion. Then they modeled associations between these subgroups and incident OA of the knee (Arthritis Rheum. 2015 Sep 28. doi: 10.1002/art.3943).
Among 885 knees from the MOST study, 203 developed radiographic tibiofemoral OA and 64 developed patellofemoral OA after up to 84 months of follow-up, the researchers reported. Latent class analysis identified four groups of MRI lesions for each knee joint, which exhibited sequentially increasing baseline severity for all MRI features except meniscal damage, the investigators added.
For the patellofemoral joint, the odds of incident knee OA rose sequentially with increasing MRI severity, ranging from 1.0 for minimal lesions to 13.7 for severe lesions (95% confidence interval, 5.0-37.0), according to the study. In contrast, the odds of incident knee radiographic OA (ROA) of the tibiofemoral joint were highest for the “mild” and “severe” groups, which had the most meniscal damage and the most extensive history of knee injury and surgery. Odds ratios for these two groups were 5.6 (95% CI, 3.4-9.4) and 5.0 (95% CI, 2.8-9.0), respectively, said the researchers. “Meniscal damage might play a prominent role in the development of incident ROA in the tibiofemoral joint but not the patellofemoral joint,” they added.
Patients in the MOST study had a high risk of knee OA at baseline, which could limit the generalizability of the findings, Dr. Niu and her associates noted.
The National Institute on Aging and National Institute of Arthritis and Musculoskeletal and Skin Disease, both a part of the National Institutes of Health, supported the study. The investigators did not report conflicts of interest.