summary TKA 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 knee. Treatment is generally revision arthroplasty with exchange of all loose components. Etiology Steps in the process include particulate debris formation macrophage activated osteolysis prosthesis micromotion particulate debris dissemination Pathophysiology factors affecting wear rate of polyethylene in TKA sterilization method manufacturing method (conventional vs. crosslinked) presence of third-body debris motion between modular tibial insert and metal tray (i.e., backside wear) roughness of femoral component counterface alignment and stability of the TKA login to view 2 more bullets demand or activity level of patient Aseptic loosening can also occur due to disruption of the cement-implant or cement-bone interface implant-cement interface is most common "weak link" compared to bone-cement interface can be avoided by minimizing lipid contamination at cement interfaces and allowing cement to fully cure before stress testing Presentation Symptoms painless early disease pain location login to view 1 more bullet aggrevating factors login to view 2 more bullets Physical exam may have minimal pain with ROM increased pain with weight bearing Radiographs recommended views AP login to view 2 more bullets lateral oblique login to view 1 more bullet findings radiolucent area around implant or cement with sclerotic border login to view 1 more bullet change in position of the implant login to view 1 more bullet progressive widening of cement-bone or bone-prosthesis interface cement cracking or fragmentation CT Scan & MRI viable options for assessing larger osteolytic lesions to aid in preoperative planning Studies Serum labs ESR normal CRP normal Differential Critical to rule out periprosthetic joint infection Treatment Nonoperative observation indications login to view 1 more bullet Operative revision TKA indications login to view 3 more bullets technique login to view 9 more bullets Techniques Revision TKA