Aseptic Loosening of Total Hip Arthroplasty as a Result of Local Failure of Tissue Homeostasis

Total hip arthoplasty (THA) is the most effective and safest method for treating severe degenerative, post-traumatic and other diseases of the hip joint. It is estimated that more than 1,000,000 THAs are performed each year globally. The incidence of primary THA increased in the period 1990 to 2002 in the USA from 47/100,000 to 69/100,000 (Kurtz et al. 2007). A similar study in Denmark reported an increased rate of THAs from 101/100,000 to 131/100,000 during the period 1996 to 2002 (Pedersen et al. 2005). More importantly, modelled future projections expect further increase in the need for THAs. It is believed that THA can reliably relieve pain and improve function in the majority of patients for a period of 15 to 20 years or more postoperatively. On this basis, with the extension of THAs to a younger and generally more active population, the expected time of service of THAs would be insufficient and the number of revision surgeries would therefore increase during this time. The Kaplan-Meier ten-year revision-free survival estimates for younger patients range from 72% (95%CI: 67-76) in Finland to 86% (95%CI: 84,5-88,2) in Sweden (Corbett et al. 2010). Hence, 14% to 28% of such patients on average did not achieve a 10-year THA functioning without revision. The main reason for late failure of THA is aseptic loosening accompanied by osteolysis followed by infection and instability of the THA that compromise more the early postoperative