Musculoskeletal injections provide a valuable diagnostic and therapeutic tool for sports medicine physicians. They can be instrumental in improving pain control and function (1).
Principles of Injections: Physicians should understand relevant anatomy and indications for injections. Informed consent should be obtained prior to the procedure (2). Aseptic technique is used and, whenever possible, single-dose vials are utilized (1). Injections may be used to identify the source of pain, as well as relieve pain to allow for a more complete examination (1). Injections can involve aspiration to aid in diagnosis, allow for pain relief, and restore joint motion (1). It is important to discuss activity limitations, post-injection pain expectations, and anticipated treatment course following injection (2).
Contraindications: Absolute contraindications to injections include the following: overlying skin breakdown or infection, septic joints or bursae, known fracture, prosthetic joint, or allergy to injectate (1–3). Relative contraindications include the following: uncontrolled diabetes (corticosteroids), immunosuppression, anticoagulation or uncontrolled coagulopathy, and lack of response to previous similar injections (1–3).
Landmark versus Ultrasound: Multiple studies have demonstrated ultrasound guidance to have superior accuracy and efficacy compared to landmark guidance (1–3). High-frequency, 15-MHz to 6-MHz linear probes are better for superficial structures, while low-frequency 5-MHz to 2-MHz curvilinear probes are better for deeper structures (1).
Anesthetics: Anesthetic agents in injections aid diagnosis, improve pain, and increase injectate volume (2). Lidocaine is most commonly used; epinephrine should be avoided in joint injections (1). Dose-dependent chondrolysis has been noted with all anesthetics, the most chondrotoxic being bupivacaine (1,2).
Corticosteroids: Corticosteroids are potent immunosuppressive and anti-inflammatory medications. Available agents vary by solubility, concentration, and duration of action (1–3). The Table presents a nonexhaustive list of common corticosteroid injection sites and typical dosing.
Intra-articular corticosteroid injections can provide short-term pain relief, particularly in treating osteoarthritis. Evidence of long-term benefit is mixed, varying by injection site (2,3). Steroid injections are contraindicated in large, weight-bearing tendons (Achilles/patellar tendons) due to the risk of collagen atrophy and tendon rupture (2). Additionally, harms likely outweigh benefits for corticosteroid injection of the plantar fascia and lateral epicondyle (2,3). Recent studies reinforce the concern that corticosteroid injections accelerate destruction of articular cartilage (2,3). Recurrent intra-articular injections should be approached with caution. Other risks associated with steroid injections include postinjection pain flare, skin atrophy, depigmentation, and liponecrosis (1,2).
Hyaluronic Acid (HA): HA is composed of polysaccharide chains naturally secreted by the synovium into the joint space. The mechanism of action is under debate. The Osteoarthritis Research Society International and American Academy of Orthopedic Surgeons do not recommend use of HA for treatment of osteoarthritis (3); however, the American Medical Society for Sports Medicine, based on comprehensive meta-analysis, recommends use of HA in individuals older than 60 years with moderate to severe osteoarthritis (4). Higher molecular weight formulations appear to be more effective and beneficial in the mid- to long-term treatment of knee OA (1).
Platelet Rich Plasma (PRP): PRP involves the injection of a concentrated volume of autologous platelets into the target location, precipitating platelet activation, cytokine and growth factor release, and, ultimately, tissue healing and repair (3). Studies support the use of leukocyte-poor PRP in osteoarthritis, particularly in younger populations (3); leukocyte-rich PRP has been shown to be beneficial in the treatment of lateral epicondylitis, when compared with corticosteroid injection (3).
The authors declare no conflict of interest and do not have a financial disclosure. The views and statements listed are those of the authors and do not represent the views of the United States Air Force, Defense Health Agency, or Department of Defense.
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5. Wu YT, Ke MJ, Ho TY, et al. Randomized double-blinded clinical trial of 5% dextrose versus triamcinolone injection for carpal tunnel syndrome patients. Ann. Neurol
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6. Wang W, Shi M, Zhou C, et al. Effectiveness of corticosteroid injections in adhesive capsulitis of shoulder: a meta-analysis. Medicine
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7. Nissen MJ, Brulhart L, Faundez A, et al. Glucocorticoid injections for greater trochanteric pain syndrome: a randomised double-blind placebo-controlled (GLUTEAL) trial. Clin. Rheumatol
. 2019; 38:647–55.