Klassifikation der acetabulären knöchernen Defekte nach Paprosky

Anwendung

Revisionsendoprothetik

Zweck
Classification system based on location and extent of femoral bone loss, with the adequacy of the
metaphyseal, diaphyseal, and cancellous bone in the femur used to predict reconstructive options

I
Minimal defects and femur does not differ significantly from that encountered in the
primary total hip; intact metaphyseal and diaphyseal bone stock; partial loss of the calcar
and AP bone
Treated as in the primary arthroplasty; managed with cemented, proximally porous-
coated, or extensively-coated implants with successful outcome.
II
Isolated to the metaphysis; intact diaphyseal bone; calcar completely deficient; increased
AP loss of cancellous bone in the metaphysis
Not amenable to proximally porous-coated implants or cementing; canal-filling, fully
porous-coated stems are preferred for distal fixation; calcar replacement may be required.
III
The difference between  Type IIIA and Type IIIB femoral defects is whether a minimum 4-
cm scratch fit can be reliably obtained near the isthmus (IIIA) or requires diaphyseal
fixation beyond the isthmus (IIIB).  Examples include cemented and porous stems with
metadiaphyseal osteolysis or asepctic loosening, proximal periprosthetic fractures, and
femurs with varus remodeling.
Must be predicted preoperatively
 
IIIA
Involve the metaphysis and the junction with the diaphysis.
Require use of a fully porous-coated stem with longer canal-filling capacity (8 or
10-inch bowed).
 
IIIB
Defects extend further into the diaphysis than Type A
Managed with similar stems or impaction grafting if the ‘tube’ is intact and the
canal width exceeds 18 mm.
IV
Represent extensive femoral metadiaphyseal damage, with thin cortices and widened
canals that preclude reliable distal fixation, and a nonsupportive isthmus
Must be predicted preoperatively.  Options include impaction allografting or use of an
allograft prosthetic composite. 
 Defects w/ associated deformity:  Commonly seen as varus and associated retroversion in
remodeling secondary to loosening of femoral component.
Defects w/ associated deformity:  An extended proximal trochanteric osteotomy serves to control
osteolysis and avoids fracturing during stem insertion.