summary THA Aseptic Loosening is a macrophage-induced inflammatory response that results in bone loss and implant loosening in the absence of an infection. Diagnosis can be made with plain radiographs of the hip. Treatment is generally revision arthroplasty with exchange of all loose components. Etiology Steps in the process prosthesis micromotion particulate debris formation macrophage activated osteolysis See wear and osteolysis basic science for full description Presentation Symptoms pain location login to view 3 more bullets aggrevating factors login to view 1 more bullet Physical exam may have minimal pain with ROM increased pain with weight bearing Radiographs recommended views AP lateral findings (xrays are not sensitive for osteolysis and typically underestimate extent of involvement) lucency > 2 mm at cement-bone or metal-bone interface component motion with stress views femoral component login to view 8 more bullets acetabular component login to view 3 more bullets Studies Serum labs ESR will be normal CRP will be normal Treatment Nonoperative observation indications login to view 1 more bullet Operative revision THA Indications login to view 3 more bullets