Accelerated knee osteoarthritis is characterized by distinct features that include destabilizing meniscal tears in two or more areas as well as other pathologies, based on data from the Osteoarthritis Initiative.
Courtesy National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
The possibility of accelerated knee osteoarthritis (AKOA) as a unique subset of knee osteoarthritis has not been well studied, wrote Jeffrey B. Driban, PhD, of Tufts University, Boston, and his colleagues.
“If specific pathologies differentiate people at risk for AKOA it may help identify adults with early-stage or high-risk for AKOA and inspire novel prevention strategies,” they wrote in their report, published in Arthritis & Rheumatology.
The researchers reviewed data from three groups of adults selected from participants in the Osteoarthritis Initiative, a cohort of 4,796 adults with KOA or at risk for symptomatic KOA who were recruited at four clinical sites in the United States. These groups included 125 with AKOA, 125 with typical knee osteoarthritis (KOA), and 125 without knee OA.
Overall, patients with AKOA were approximately seven times more likely than were patients with KOA to have destabilizing meniscal tears in two or more areas at the time of the index visit (42% vs. 14%); less than 5% of adults with no KOA experienced destabilizing meniscal tears. In addition, patients with AKOA were more than four times as likely to have miscellaneous pathology starting the year before the index visit, compared with those without AKOA.
Approximately 63% of the participants in each group were women, and the majority were overweight. The average age, weight, and global impact of arthritis were greater in the AKOA group when compared against the typical KOA and no-KOA groups.
Participants were assessed via MRI reviewed by radiologists who were blinded to the groups.
At the index visit, 49% of adults with AKOA had either a destabilizing meniscal tear or miscellaneous pathology, compared with 15% of adults with KOA and 6% of adults without KOA.
Adults with AKOA also showed significantly greater cartilage loss prior to the index visit in comparison with typical KOA patients, and AKOA patients had less cartilage in the medial and lateral tibia and medial femur, compared with adults who had typical KOA or no KOA after the index visit.
Adults who developed AKOA showed a significantly higher bone marrow lesion volume when compared against the typical KOA and no-KOA groups at 1 year prior to the index visit, and their bone marrow lesion volume increased on average 13 times more compared with typical KOA patients over the 2 years before the index visit, the researchers noted (2.00 mL vs. 0.15 mL, respectively).
“These findings add to the evidence that AKOA is different [from] the typically perceived archetype of slow-progressing osteoarthritis” with a unique risk profile, the researchers said.
The study findings were limited by several factors, including the relatively small sample size, uncertain timing of disease onset, a potentially limited definition of a destabilizing meniscal tear (defined as a root tear, radial tear, or complex tear, which almost always featured a radial component), a lack of a universal AKOA pathology, and some missing MRI data, the researchers noted. However, the results support previous studies suggesting a link between meniscal pathology and increased risk for AKOA, they said.
“It is important to acknowledge that it remains unclear if AKOA has any relation to type 2 rapidly progressive osteoarthritis, which was characterized by a more dramatic joint space narrowing (2 mm or more within 1 year) and greater abnormal bone loss/destruction,” they noted.
“Future research with a larger sample size of adults at risk for AKOA may help further refine our understanding of AKOA and help develop a clinically useful predictive model,” they added.
The study was supported in part by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases, and private funding included Merck, Novartis, GlaxoSmithKline, and Pfizer. The researchers had no financial conflicts to disclose.
SOURCE: Driban JB et al. Arthritis Rheumatol. 2018 Dec 28. doi: 10.1002/art.40826.