Classification of bone defects in failed prostheses.

The authors report a classification system in grades, based on preoperative x-rays of the bone loss surrounding a loosened implant that may be cemented or cementless. Moreover, this classification system allows for the prior choice of which prosthesis to use at the time of reimplantation, and which type of graft depending on whether or not the residual bone guarantees mechanical hold of the implant.