Knee osteoarthritis is a common debilitating condition in North Americans characterized by inflammation of the joint and often accompanied by inflammation of the synovial membrane (synovitis). Researchers investigated the effects of anti-inflammatory corticosteroid injections as treatment despite their anti-anabolic effects.
Knee osteoarthritis affects millions of people across the globe and is a leading degenerative orthopaedic condition. Patients experience pain, joint deterioration and loss of function due to progressive inflammation. Said inflammation can also be found in the synovial cavities of the joint (synovitis), and can further exacerbate symptoms.
To deal with the inflammation, it is theorized that known anti-inflammatory corticosteroids could be injected into the joint and decrease disease progression. However, corticosteroids have anti-anabolic properties that could damage healthy cartilage over time. To date, studies have been inconclusive regarding the effects of corticosteroid injections on soft knee tissue.
In a recent study published in JAMA, McAlindon and colleagues investigated the effects of intra-articular corticosteroid injections on pain and knee cartilage volume. The study included 140 participants, aged 45 years or older and diagnosed with knee osteoarthritis. Participants were separated into 2 groups, an experimental group that received corticosteroid injections and a control group that received saline injections. Injections were administered every 3 months for 2 years and knee assessments were conducted at each visit. More extensive tests, such as MRIs, were conducted annually. Pain was self-reported and knee cartilage volume was assessed via MRI.
The results show that patients who received corticosteroid injections had significantly greater cartilage volume loss and no difference in pain compared to those who received saline injections. These results are in contrast with a previous study that reported no adverse effects from corticosteroid injections. This difference is likely due to varying techniques used to obtain measurements. McAlindon and colleagues used MRI to assess knee cartilage volume, which provides greater detail than the radiography technique used in the contrasting study. Though neither group showed progression of osteoarthritis, over longer periods of time the cartilage volume loss could lead to progression or the development of other adverse conditions. Also, some theorize that saline injections could be a treatment for knee osteoarthritis. However, it has been noted that intra-articular injections have a strong placebo effect and no study has included sham injections, so this theory remains inconclusive.
In conclusion, this study found significantly greater cartilage volume loss from intra-articular corticosteroid injections compared to saline injections. Cartilage volume loss could lead to greater health problems down the line, and as such, should not be used as a treatment for patients suffering from knee osteoarthritis.
Written By: Wesley Tin, MBSc