Epidemiology of osteolysis: backside implant wear.

Osteolysis is an emerging problem in patients who undergo total hip arthroplasty and total knee arthroplasty (TKA). Before the introduction of modular components, osteolysis was not as prevalent in patients who underwent TKA. Although polyethylene wear and the generation of small-particle debris were linked to the presence of osteolysis in patients who have undergone total hip arthroplasty, the fatigue-type wear and larger wear particles often seen with TKA were not thought to invoke the cellular response that causes osteolysis. Despite the lack of an identifiable cause for the osteolysis, the number of knees that developed lesions continued to increase. Therefore, modular components were examined to determine whether this innovation in TKA was actually contributing to the manifestation of osteolysis.