Femoral defects. A, Segmental defect: loss of femoral cortical bony support. It may be partial and proximal involving loss of bone through level of femur, or it may be intercalary lesion with intact bone above and below or involve greater trochanter. Most severe degree of segmental bone loss is complete proximal circumferential loss of bone. B, Cavitary defect: loss of cancellous or endosteal cortical bone without violation of outer cortical shell. Ectasia is severe form of cavitary defect in which femoral cavity is expanded. C, Combined defects: combination of segmental and cavitary bone loss in femur. It can occur in combination through any of three levels of femur. D, Malalignment: distortion of femoral architectural geometry in either rotational or angular plane. E, Femoral stenosis: partial or complete occlusion of femoral intramedullary canal. F, Femoral discontinuity: interruption of integrity of femoral shaft, usually as result of fracture or nonunion, with or without presence of implant. G, Femoral levels.