Background/Purpose:  Ultrasound (US)-guided injections in musculoskeletal medicine typically utilize either local puncture site sterility or conventional surgical sterility. We report on the safety and complications of US-guided injections using local puncture site sterility.

Methods:   Local puncture site sterility requires an initial cleansing of the injection site with chlorhexidine antiseptic.  The clean, non-sterile US-gel is then placed on the clean, non-sterile US-probe and then both on the skin.  Contamination is avoided through use of a longer needle that allows increased distance between the needle puncture site and US-gel-probe (Figure 1A).  Under IRB approval, we analyzed 1115 consecutive US-guided corticosteroid injections (in 81.5% females and 18.5% males) to treat predominantly localized osteoarthritis and rheumatoid arthritis.  Patient outcomes at 1, 3, 6 and 12 months post-procedure were reviewed for procedural-related complications.

Results:   The 1115 US-guided injection procedures consisted of 390 knees (35%), 187 shoulders (17%), 186 carpal tunnels (17%), 120 fingers (interphalangeal and metacarpophalangeal joints, trigger finger) (11%), 47 sacroiliac joints (4.2%), 42 ankles (3.8%), 39 greater trochanteric bursa, (3.5%), 34 wrists (3%), 20 elbows (1.8%), 20 hips (1.8%), 11 popliteal cysts (1%), 11 feet (intertarsal joints) (1%), and 8 toes (interphalangeal and metatarsophalangeal joints (0.7%).  Dermal atrophy (Figure 1B) occurred in 51 cases (4.6%), hemorrhage (Figure 2 A) in 1 (0.09%), cellulitis (Figure 2B) in 1 (0.09%), septic joint in 0 (0%), and tendon rupture 0 (0%). All complications resolved with time and proper therapy.  The single infection was due to methicillin-sensitive Staphylococcus aureus suggesting endogenous contamination from the patientÕs skin.

Conclusion:   US-guided musculoskeletal injections using local puncture site sterility are safe with dermal atrophy being the most common adverse outcome (4.6%).  Serious complications, including infection, occur at an incidence less than 0.1% indicating that US-guided injection with local puncture site sterility is an acceptably safe procedural technique.

Figure 1.  A. Local puncture site sterility injection.  B. Dermal Atrophy after US-guided carpal tunnel injection.

Figure 2. A.  Hemarthrosis after US-guided injection.  B. Digital cellulitis after US-guided injection.