Ultrasound-guided therapeutic procedures in the musculoskeletal system.

Ultrasound allows the exploration of most of the musculoskeletal system, including lytic bone lesions. Its flexibility, availability, and low cost make it the best tool to guide interventional therapeutic procedures in any musculoskeletal system lesion visible on ultrasound. These techniques include drainages of abscesses, bursitis, hematomas or muscular strains, treatment of cystic lesions (ganglions, Baker's cysts), arthrocentesis, injection of substances in joints and soft tissues, and aspiration of calcific tendinitis. Although the puncture of joints for arthrocentesis and injection of substances are performed by clinicians using palpation, the use of ultrasound guidance improves the effectiveness of the technique especially for small or poorly accessible lesions and joints and for obese patients. Drainage can be performed using catheters or needles and can avoid a more aggressive approach most of the time. Intracavitary urokinase helps when the aim is to drain clotted hematomas or fibrinous collections. Injection of corticoids is useful in the treatment of ganglia, Baker's cysts, tendinitis, and noninfected arthritis. Calcific tendinitis of the shoulder can be effectively treated using percutaneous "lavage" with lidocaine. Calcifications usually disappear and symptoms improve in nearly 90% of the cases within a year. Most of these techniques are low cost and require only a moderate skill. Ultrasound-guided procedures are useful tools to effectively treat some diseases of the musculoskeletal system and should be routine in any imaging department.