Abstract

Keywords: Intra-articular steroid; Periarticular diseases; Hydrocortisone; Osteoarthritis; Pubivacaine; Lidocaine

Abbreviations:IASI: Intra-articular Steroid Injections; OA: Osteoarthritis

Letter to the Editor

Intra-articular steroid injections (IASI) represent one of the most common available tools for the treatment of articular or periarticular diseases. They were introduced many years ago by the famous American rheumatologist Joseph L. Hollander, who in 1951 first injected hydrocortisone (at this time called substance F) in the joints of patients with rheumatoid arthritis [1]. Since then, there has been a progressive expansion in clinical use of IASI, with millions of patients treated, especially with osteoarthritis (OA). So, I believe that few specialists in joint diseases can claim to have never used it. However, despite this, a clear optimization of their use is still a matter of debate, in accordance with the caution with which the main international guidelines for OA recommend it [2]. Due to the relatively advantageous risk-benefit ratio, their use is largely empiric, and side effects and/or poor effectiveness are attributed more to the patient’s responsivity than to the characteristics of the product used. As regards this aspect, the most used are particulate formulations, usually acetylated, which, in comparison with soluble products, exhibit longer duration but with a slower analgesic effect. For this reason, most clinicians prefer associate anesthetics, in particular pubivacaine or lidocaine, to obtain a more rapid symptomatic action. However, this combination has been criticized by some authors, especially for a risk of chondrotoxicity, but without a robust basis of evidence [3, 4]. For this reason, I read with interest the study by Guarise et al., entitled “Physicochemical Compatibility of Hydrocortisone with Anaesthetics: Implications for Intra-Articular Treatments,” recently published in this Journal [5], which was designed to offer a model useful to explain some particular mechanisms of IACI. The authors have evaluated the compatibility and stability of hydrocortisone succinate combined with either bupivacaine or lidocaine by using the fetal bovine serum, which replicates adequately the synovial fluid environment. Thus, they have demonstrated a stability of pH, which reflects a homogeneous distribution of hydrocortisone and anesthetic and, on the other hand, the lack of crystal formation by lidocaine, which exhibits better solubility in comparison to bupivacaine. The practical implications of these observations are not negligible, because among the potential causes of chondrotoxic effects of IACI were the tendency to precipitate and form aggregates by long-acting steroids, especially when used in combination with anesthetics [4]. These aspects may have relevance also in the short term, because the occurrence of some under-estimated side effects, such as skin or soft tissue atrophy and calcifications, may be found at rates as high as 50% and can be located in the pericapsular, intracapsular, or intra-articular location [6]. The probable causal mechanism of these calcifications is related to local tissue injury from the needle and low water solubility of extra-articular corticosteroids with chronic granulomatous and subsequent dystrophic calcification [7]. It is surprising that all these aspects are rarely considered and rarely reported, although during friendly conversation among experts, these cases are frequently seen, especially with triamcinolone acetonide, a fluorinated substance [8]. I should admit that our contribution as experts in some international task forces elaborating recommendations for OA management was based more on our personal experience than on scientific evidence. In keeping personally, I prefer to use long- acting steroids for large joints and non-fluorinated long-acting steroids for small superficial joints, while for entheses and carpal tunnel syndrome, my choice is short-acting steroids. However, there is little evidence to guide the selection of one steroid over another. In keeping with the very recent guidelines from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, the American Society of Interventional Pain Physicians, and the International Pain and Spine Intervention Society, the recommendation concerning the choice of corticosteroid was, “There is insufficient evidence to recommend one preparation of intra-articular corticosteroid over another.” Thus, finally, despite being introduced more than 70 years ago, IACI use needs to be further optimized..