Revision THA Flashcards
What is the most common reason for revision in the Charnley “low-friction” total hip arthroplasty?
Acetabular loosening
What are the AAOS and Paprosky classifications for acetabular bone loss in THA?
AAOS:
Type I (segmental)-Loss of part of the acetabular rim or medial wall
Type II (cavitary)-Volumetric loss in the bony substance of the acetabular cavity
Type III (combined deficiency) Combination of segmental bone loss and cavitary deficiency
Type IV (pelvic discontinuity) Complete separation between the superior and inferior acetabulum
Type V (arthodesis) Arthrodesis
Paprosky:
Type I- Minimal deformity, intact rim
Type IIA- Superior bone lysis with intact superior rim
Type IIB- Absent superior rim, superolateral migration
Type IIC- Localized destruction of medial wall
Type IIIA- Bone loss from 10am-2pm around rim, superolateral cup migration
Type IIIB- Bone loss from 9am-5pm around rim, superomedial cup migration
What are the AAOS and Paprosky classifications for femoral bone loss in THA?
AAOS:
Type I (segmental)- Loss of bone of the supporting shell of femur
Type II (cavitary)- Loss of endosteal bone with intact cortical shell
Type III (combined)- Combination of segmental bone loss and cavitary deficiency
Type IV (malalignment)- Loss of normal femoral geometry due to prior surgery, trauma, or disease
Type V (stenosis)- Obliteration of the canal due to trauma, fixation devices, or bony hypertrophy
Type VI (femoral discontinuity)- Loss of femoral integrity from fracture or nonunion
Paprosky:
Type I- Minimal metaphyseal bone loss
Type II- Extensive metaphyseal bone loss with intact diaphysis
Type IIIa- Extensive metadiaphyseal bone loss, minimum of 4 cm of intact cortical bone in the diaphysis
Type IIIb- Extensive metadiaphyseal bone loss, less than 4 cm of intact cortical bone in the diaphysis
Type IV- Extensive metadiaphyseal bone loss and a nonsupportive diaphysis
How are Paprosky II and IIIa femurs treated?
1) Uncemented fully porous coated
2) Distal fit modular stem (can also treat Paprosky IIIb; less than 4cm intact cortical diaphyseal bone)
Paprosky IV (loss of diaphyseal support) is treated with oncology megaprosthesis
What is the most common cause of failure in revision acetabular surgery with cup and morselized allograft?
Allograft resoprtion; in larger defects that comprise >50% of the weight bearing surface a reconstruction cage with corticocancellous autograft is recommended
What is the most common complication of isolated liner exchangein THA?
Instability
