Musculoskeletal infections are common, and the delay between diagnosis and
treatment is the most important determinant of outcome. Ultrasound (US) is
a widely available imaging modality that can be used quickly for the assess
ment of cellulitis, abscess, septic bursitis, tenosynovitis, arthritis, and
osteomyelitis. Identification of the causative micro-organism is essential
for diagnosis and to establish optimal treatment. Because of its multiplan
ar and real-time imaging capability, US is the technique of choice to guide
needle aspiration of any suspicious fluid collection, abscess, synovial sh
eath, bursa, or joint for microbial analysis. Because the imaging is not de
graded by metal artifact, US is an excellent modality for imaging infectiou
s processes around orthopedic hardware.