Background: Total hip arthroplasty (THA) is one of the most common and successful surgical procedures in orthopedic surgery and clinical success can be characterized by the revision rate and improvement of function, as well as the patient's satisfaction and pain. Despite the clinical success of primary THA with 10-year survival rates as high as 96 % (Swedish Hip Arthroplasty Register, 2011), the prevalence of groin pain after conventional total hip replacement ranges from 0.4 to 18.3 % and activity-limiting thigh pain is still an existing problem linked to the femoral component of uncemented hip replacement in up to 1.9 to 40.9 % of cases in some series. Obvious causes of failure might be identified with clinical examinations and standard radiographs only, whereas the unexplained painful THA still remains a challenge for the surgeon. They can be classified into extra- and intraarticular disorders, the latter being divided into biological and mechanical origins. The onset of the pain after the operation and the differentiation between pain in motion and at rest are helpful to distinguish between mechanical and non-mechanical problems. An infection should be the first diagnosis to be ruled out in a painful THA. It is generally accepted that a clear understanding of the failure mechanism in each case is required prior considering revision surgery. Method: In this review a practical diagnostic algorithm is described for failure analysis in more detail. The evaluation of a painful THA includes a detailed history with an extended analysis of the type of pain, thorough clinical examination including the spine and knee joints, radiographic and laboratory analysis, as well as invasive examinations like joint aspiration and biopsies. Conclusion: This diagnostic algorithm offers an important tool for a sufficient failure analysis in almost all patients with painful THA.
