Injecting hyaluronic acid (HA) instead, or managing the condition without injections, may better preserve knee structure and cartilage, according to results of two related studies presented at the annual meeting of the Radiological Society of North America.
The findings come nonrandomized, observational cohort studies, leading knee OA experts to call for further study in randomized trial settings. In the meantime, shared decision-making between patients and clinicians is advised on the use of these injections.
For knee OA, most patients seek a noninvasive treatment for symptomatic relief. “At least 10% of these patients undergo local treatment with injectable corticosteroids or hyaluronic acid,” the lead author of one of the studies, Upasana Upadhyay Bharadwaj, MD, research fellow in musculoskeletal radiology at the University of California, San Francisco, said in a video press release.
Researchers in both studies used data and images from the(OAI), a multicenter, longitudinal, observational study of 4,796 U.S. patients aged 45-79 years with knee OA. Participants were enrolled from February 2004 to May 2006.
Two studies draw similar conclusions
In one study, Dr. Bharadwaj and colleagues found that HA injections appeared to show decreased knee OA progression in bone marrow lesions.
They investigated 8 patients who received one CS injection, 12 who received one HA injection, and 40 control persons who received neither treatment. Participants were propensity-score matched by age, sex, body mass index (BMI), Kellgren-Lawrence (KL) grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Physical Activity Scale for the Elderly (PASE).
The researchers semiquantitatively graded three Tesla MRI scans that had been obtained at baseline, 2 years before the injection, and 2 years after the injection, using whole-organ MRI score (WORMS) for the meniscus, bone marrow lesions, cartilage, joint effusion, and ligaments.
They quantified OA progression using the difference in WORMS between baseline and 2-year follow-up, and they used linear regression models, adjusted for age, sex, BMI, KL grade, WOMAC, and PASE, to identify the link between type of injection and progression of WORMS.
At 2 years, the authors found a significant association between CS injection and postinjection progression of WORMS over 2 years for the knee overall, the lateral meniscus, lateral cartilage, and medial cartilage. There was no significant link between HA injection and postinjection progression of WORMS or between either injection type and progression of pain, as quantified by WOMAC. There was also no significant difference in progression of WORMS over the 2 years prior to injection for CS and HA injections.
“Corticosteroid injections must be administered with caution with respect to long-term effects on osteoarthritis,” Dr. Bharadwaj advised. “Hyaluronic acid injections, on the other hand, may slow down progression of knee osteoarthritis and alleviate long-term effects while offering similar symptomatic relief to corticosteroid injections. Overall, they are perhaps a safer alternative when looking at medium- and long-term disease course of knee osteoarthritis.”
In the second study, lead author Azad Darbandi, MS, a fourth-year medical student at Chicago Medical School, North Chicago, and colleagues found that patients who received CS injections experienced significantly more medial joint space narrowing.
They identified 210 knees with imaging at baseline and at 48 months that received CS injections, and 59 that received HA injections; 6,827 knees served as controls. The investigators matched 50 patients per group on the basis of confounding factors, which included age, sex, BMI, comorbidities, surgery, and semiquantitative imaging outcomes at baseline. They performed ANCOVA testing using 48-month semiquantitative imaging outcomes as dependent variables and confounding variables as covariates.
The researchers analyzed joint space narrowing, KL grade, and tibia/femur medial/lateral compartment osteophyte formation and sclerosis.
At 4 years, the average KL grade in the CS group was 2.79, it was 2.11 in the HA group,;and it was 2.37 in the control group. Intergroup comparisons showed significant differences in KL grade between CS and HA groups and between CS and control groups. Medial compartment joint space narrowing was 1.56 in the CS group, 1.11 in the HA group, and 1.18 in controls. There was a significant difference between the CS and control groups. Other dependent variables were not significant.
“These preliminary results suggest that corticosteroid injections accelerated the radiographic, specifically medial joint space narrowing and Kellgren-Lawrence grading, whereas hyaluronic acid injections did not,” Mr. Darbandi said in an interview.
“OA radiographic progression does not always correlate with clinical progression, and further research is needed,” he added.
Proper matching of patients at baseline for confounding factors is a strength of the study, Mr. Darbandi said, while the retrospective study design is a weakness.