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

Site Preparation and Technique

Sterility when performing intra-articular injections is essential; however, the technique of obtaining that sterility varies among providers, and there does not seem to be any consensus on standard techniques.[28,29] Commonly used skin antiseptics include isopropyl alcohol, chlorhexidine, and povidone-iodine. Some providers use sterile gloves if touching the injection site after preparation, whereas others use a no-touch technique and use nonsterile gloves. Charalambous et al[28] surveyed providers in the United Kingdom concerning their practice of intra-articular steroid injections in the knee and found that 57.6% of the respondents used alcohol-based swabs only, whereas the rest used either Betadine or chlorhexidine to prepare the injection site. Complete antiseptic techniques, including the use of disinfectants, sterile gloves, and sterile towels to create a sterile field and the use of a different needle to withdraw the medication, were used by only 13% of the respondents, whereas no gloves, even nonsterile, were used by 53.4% of the respondents.[28] Although sterile gloves are not required because of the use of a no-touch sterile technique, universal precautions with personal protective equipment include and recommend the use of nonsterile gloves. Sterile gloves can be up to 50 times more expensive than nonsterile gloves, and their cost-effectiveness have not been established.[29]

Although a lack of clinical data exists on intra-articular knee injection site preparation, the literature contains studies looking at venipuncture that may be used for guidance. In a randomized trial of 2% alcoholic chlorhexidine compared with 10% aqueous povidone-iodine for venipuncture site disinfection for blood cultures, chlorhexidine was superior with a blood culture contamination rate of 3.2% compared with 6.9% with povidone-iodine (P < 0.001).[30] The authors mention that the maximum antiseptic effect of povidone-iodine occurs after 1.5 to 2 minutes, whereas chlorhexidine needs only 30 seconds for the maximum antiseptic effect, so the short antiseptic dry times may have biased the results. In addition, chlorhexidine may not necessarily be the best antiseptic. Recently, Martínez et al[31] performed a blinded, randomized study comparing the rate of blood culture contamination between 70% isopropyl alcohol and 2% chlorhexidine skin antiseptic use and found no difference (0.9% versus 1.9%, respectively; P = 0.3). Therefore, the best skin disinfectant remains undefined.

Another consideration is the common practice of using of ethyl chloride as a topical anesthetic spray. Ethyl chloride is a refrigerant, so it will cool the skin and decrease the pain of the needle puncture. Concerns exist about its use because it is a nonsterile spray, and some providers will repeat the skin disinfectant after its use. Polishchuk et al[32] performed a prospective, blinded, controlled study comparing culture growth from skin samples before alcohol preparation, after alcohol preparation but before ethyl chloride application, and after ethyl chloride application. No significant difference was found between bacteria growth on samples taken after alcohol skin preparation but before ethyl chloride application and after ethyl chloride application (3% versus 5%, respectively; P = 0.65). The ethyl chloride spray was directly applied to empty Petri dishes and culture broth and compared with controls with no spray applied. No significant difference was found in bacterial growth (P = 0.80).[32]

When an effusion is present, providers may consider aspirating the knee before injection to provide additional pain relief and improved motion in the knee. Leung et al[33] performed a retrospective pilot study and found benefit in aspirating osteoarthritic knees before a steroid injection; however, patient-reported improvement was better in the injection-only group. Gaffney et al[34] conversely found a statistically significant patient-reported benefit from aspiration, followed by steroid injection, compared with no aspiration at 1 week (92% compared with 61%; P < 0.05) in their randomized prospective placebo-controlled study. The benefit continued at 6 weeks, with 66% of those aspirated reporting benefit, whereas 44% of those not aspirated found benefit (statistical significance not reported). When an aspiration is performed before steroid injection, indications for fluid analysis include concern for inflammatory arthritis or crystal arthropathy. Fluid analysis should also be performed if concern for septic arthritis, and a steroid injection should not be given in this setting.

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