The Use of Structural Allograft in Primary and Revision Knee Arthroplasty with Bone Loss

Table 2

Classification of Tibial and Femoral Bone Loss [8].

Type	Type of Bone Loss	Description
(1)	No notable loss of bone stock	There may be erosion of the endosteal bone, but no involvement of the cortex. There has been no migration of the primary component, and bone is largely intact.
(2)	Contained loss of bone stock with cortical thinning	The canal is widened, but there is still an intact cortical sleeve.
(3)	Uncontained (segmental) loss of bone stock involving <50% of medial and/or lateral condyle	Uncontained bone loss represents less than 50% of medial and/or lateral femoral and/or tibial condyle and is less than 15 mm in depth.
(4)	Uncontained (segmental) loss of bone stock >50% of medial and/or lateral condyle	Uncontained bone loss represents more than 50% of medial and/or lateral femoral and/or tibial condyle and is more than 15 mm in depth.