Steroid injections cause thinner knee cartilage – does this happen in facet joints?

Do Steroid Injections Damage Facet Cartilage?

When patients have back pain that is not responding to noninvasive interventions (oral anti-inflammatories, heat/cold applications, exercise, posture improvement, physical therapy, etc.) the cause may be arthritis of the spine’s facet joints. The standard “definitive” diagnosis is a nerve block (numbing anesthetic) injected into the joint to interrupt pain signals to the brain. If it works to stop the pain for several hours, it “proves” that the deteriorated joint is the source of the pain. The patient may be offered a treatment that uses periodic injections of a combination anesthetic and steroid. Usually these injections may be given up to three times per year, but research suggests it is difficult to predict who will benefit from these injections.ⁱ

A new study on steroid injections for the relief of knee pain due to arthritis caught my attention. The published paper by McAlindon et al. (2017)ⁱⁱ reports a randomized trial comparing an injected steroid, triamcinolone, with a placebo (saline or salt water). The injections were given every 12 weeks (every 3 months) for 2 years, and the patients were followed by both self-report and annual MRI to assess cartilage thickness. The patients did not know which substance they were receiving, and all patients had the same protocol.

The study’s results cast doubt on the pain relief value of the steroid, especially since there was virtually no difference in pain relief, knee function, stiffness or walking between the two groups over the 2 years. However, one finding is sobering: those who received the steroids actually had thinner cartilage by the end of the study period. And while the average loss was 0.16mm (which objectively is not much) the amount is statistically significant – that is, it can’t be attributed to any other factor than the steroid. So, this is not good news for steroid injections into arthritic knees other than a very occasional, possible measure during flares of arthritis pain.

This brings me back to the use of anesthetic/steroid injections for the tiny facet joints. Keeping in mind that such injections are limited to 3 times per year, or roughly every four months instead of every 3 months as in the knee study, perhaps there is less negative effect on the cartilage. On the other hand, facet joint cartilage is much thinner than knee joint cartilage because the large knee joints absorb much more shock and stress over a lifetime. While accurate cartilage measures are difficult, it is estimated that on average facet joint cartilage is around 0.8mm vs. knee cartilage at 2.5-3.5mmⁱⁱⁱ (and in some places much thicker.) While I was unable to locate published documentation that facet joint steroid injections have a similar thinning effect on cartilage in that location, the knee cartilage article raised the concern in my mind.

At our Sperling Medical Group, we offer a drug-free, noninvasive treatment to deactivate nerve signals by aiming MRI-guided focused ultrasound (MRgFUS) at the precise nerve area that transmits pain messages from the joint to the brain. The soundwaves come from numerous different angles, and are harmless to healthy tissue. Where they finally intersect, however, they create enough heat to destroy the targeted area on the nerve. There is nothing inserted into the body, and accuracy is assured thanks to the visual scans as well as MRI thermometry to track the temperature of tissue changes.

If you or a loved one has a history of facet joint pain that no longer responds to conventional treatments, contact our Center to find out if MRgFUS is an appropriate treatment for you.

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ⁱAnand S, Butt MSM. Patients’ response to facet joint injection. Acta Orthop. Belg., 2007, 73, 230-233.
ⁱⁱMcAlindon TE, LaValley MP, Harvey WF, Price LL et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: a randomized clinical trial. JAMA. 2017 May 16;317(19):1967-75.
ⁱⁱⁱSimon P, Espinoza Orias AA, Kotwal N, Inoue N et al. 3D analysis of lumbar spine facet joint cartilage thickness distribution. Paper delivered at the ASME 2011 Summer Bioengineering Conference, June 2011. DOI: 10.1115/SBC2011-53894.