Psoas abscess associated with infected total hip arthroplasty: a case report.

Psoas abscess (PA) is an uncommon disease and its diagnosis is difficult. It can be primary or secondary. Primary abscesses are of unknown origin and are presumably caused by haematogenous or lymphatic spread from a distant infectious focus. Secondary PA is caused by spreading from a contiguous infected structure, such as vertebrae (espondilodiscitis) or mesenteric abscesses (Crohns disease). PA infrequently has been associated with an infection of total hip arthroplasty (ITHA). The correct diagnosis in these cases is difficult due to the clinical similarities between PA and ITHA. Since connection between PA and ITHA is established through the acetabulum, we consider that computed tomography (CT) is the most accurate radiological test because of its efficacy in evaluating the bone structure, and the optimum therapeutic strategy is two-stage replacement surgery. We report one case of PA associated with ITHA and a review of the previous literature.