Intra-Articular Corticosteroid Injections for Symptomatic Knee Osteoarthritis

What the Orthopaedic Provider Needs to Know

Cody L. Martin, MD; James A. Browne, MD

Disclosures

J Am Acad Orthop Surg. 2019;27(17):e758-e766. 

In This Article

Combination With Local Anesthetics

It is common for healthcare providers to combine a local anesthetic with the intra-articular corticosteroid before injection.[16] Reasons for using a local anesthetic include providing immediate pain relief from intra-articular pathology (ie, diagnostic and therapeutic effects), diluting the steroid preparation, and moderating or eliminating the postinjection flare. The immediate pain relief that a patient may receive with an intra-articular local anesthetic can aide in diagnosing the patient's predominant cause of pain if it is multifactorial. It is not uncommon for patients with knee osteoarthritis to have other sources of pain around the knee (ie, bursitis, tendinitis, and neuritis, especially saphenous neuritis), which are sometimes wrongfully attributed to osteoarthritis pain. If a substantial portion of the patient's pain is relieved after an intra-articular injection with a local anesthetic combination even if it is for a few hours, it can be inferred that a notable portion of the patients' pain is due to an intra-articular source.

Potential drawbacks exist with using local anesthetics mixed with corticosteroids. Many laboratory studies demonstrate that both corticosteroids and local anesthetics may be chondrotoxic independently and when used in combination.[19,20] Clinical data concerning chondrolysis due to intra-articular local anesthetic use are mostly related to continuous infusions into the glenohumeral joint after shoulder surgery, but cases involving the knee are reported. In a systematic review concerning the use of a local anesthetic on the articular cartilage found 167 clinical cases, with 163 (97.7%) involving a pain pump infusion of continuous local anesthetic, and bupivacaine, lidocaine, ropivacaine, and levobupivacaine all showed some toxicity to the cartilage.[20] Adverse effects attributable to local anesthetics mixed with a single intra-articular steroid injection may not be clinically relevant compared with infusion pumps, but limited clinical data and no randomized control trials are available, so providers should at least be aware of the chondrotoxic effect seen in laboratory studies. Clinical data regarding the potential for chondrotoxicity will be discussed later in this article.

An issue that has been mentioned in the literature when combining steroids with local anesthetics is that of crystallization or flocculation.[4,9] The phenomenon is related to the pH and particle size of the solution.[21] The clinical and in vivo effects from this crystallization are not known. It may decrease the bioavailability of the local anesthetic or affect the efficacy of the corticosteroid. Some providers inject the anesthetic separately from the corticosteroid by exchanging syringes while the needle remains in the patient to reduce the risk of this phenomenon.

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