Repeated use of corticosteroid injections in knee osteoarthritis may accelerate structural degeneration, a new study suggests.
While previous research has shown increased cartilage loss in people with knee OA who have regular steroid injections, new evidence from a Chinese-led trial shows that intra-articular corticosteroid use is also associated with detrimental joint structural changes.
The findings come from a ‘real world’ study of 148 patients who received intra-articular corticosteroids (IAC) for knee OA. Their knee structural changes – as measured by Kellgren–Lawrence Scale (>1) and changes Joint Space Width (JSW) – were compared with a propensity-matched group of patients with knee OA who did not receive IACs.
During four years of follow up, rates of Kellgren–Lawrence Scale worsening were 21.7/100 person-years in the IAC cohort and 7.1/100 person-years in the non-IAC cohort.
Hazard Ratios for KL worsening were 3.02 for patients who started IAC and 4.67 for patients who had continuous IAC compared to the comparator group.
For Joint Space Narrowing, the Hazard Ratios were 2.93 for initiation of IACs and 3.20 for continuous IACs.
The results were independent of the effect of the major confounders, and remained stable in various sensitivity analyses, “suggesting that the initiation of IACs and continuous IACs may have a detrimental effect on knee OA progression,” concluded the authors of the study, who included Dr David Hunter of the Rheumatology Department, Royal North Shore Hospital and Institute of Bone and Joint Research, Kolling Institute, University of Sydney.
Writing in Osteoarthritis and Cartilage, the authors noted that IACs could offer pain relief for about six weeks in people with knee OA, but this benefit may be outweighed by detrimental effects on joint structure.
“Our findings of the potential detrimental effects of IACs on knee ROA progression raise the concern of its long-term effectiveness on knee pain management, especially as previous studies have shown that higher KL grade and decreased JSW were associated with knee pain,” they wrote.
The findings also raised questions about the role of inflammation and synovitis in progression of OA, given the anti-inflammatory effects of IACs, they said.
As to possible mechanisms to explain the deleterious effects, “corticosteroids may induce chondrocyte apoptosis, decrease cell viability, suppress the expression of matrix proteins, or promote calcium pyrophosphate dihydrate crystals formation that may accelerate cartilage degeneration,” they noted.
The findings warrant replication in larger prospective studies, the researchers concluded.
Australia’s Medicare Review Taskforce recently announced that it would be restoring MBS rebates for joint injections that were withdrawn in 2009.