Principles of acetabular reconstruction
Restore center of rotation
Component containment with secure fixation
Paprosky classification bone loss
|
Femoral head center migration |
Ischial osteolysis |
Kohler line | Teardrop | Description | |
|---|---|---|---|---|---|
| Type I | None | Intact | Intact | Intact |
Minimal deformity with intact rim Medial wall / anterior & posterior column intact No superior migration hip center |
| Type IIA |
Mild < 3cm |
None | Intact | Intact |
Superior bone lysis Superior rim intact |
| Type IIB |
Moderate < 3cm |
Mild | Intact | Intact |
Superior rim deficient Superolateral migration |
| Type IIC |
Mild < 3 cm |
Mild | Disrupted | Moderate | Medial defect but wall intact |
| Type IIIA |
Severe > 3cm |
Moderate | Intact |
Moderate lysis |
Severe > 2 cm superolateral migration Medial wall and posterior column lysis Bone loss 10 - 2 o'clock |
| Type IIIB |
Severe > 3cm |
Severe | Disrupted | Severe |
Severe > 2 cm superomedial migration Damage to medial wall / posterior & anterior column Bone loss 9 - 5 o'clock |
Minimal bone loss / > 50% host bone contact / normal hip center
Acetabular revision options
Large hemispherical porous coated uncemented cups / jumbo cups
- rim fit available with > 50% host bone contact
- minimal elevation of hip center
- Paprosky Type I, IIA, IIB, IIC
Results
- systematic review of jumbo cups in 950 revision THA
- 95% survival at mean 9 years
- mean elevation hip center after revision 10 mm
- mean LLD 5 mm
Cases
Paprosky Type IIB revision to jumbo cup
Paprosky Type IIC revision to jumbo cup with medial particulate allograft
Segmental bone loss + elevation of hip center
Acetabular revision options
Hemispherical uncemented implant + modular porous trabecular metal augments
- off the shelf implants of varying size and shape
- size to defect and screw in place
- cement in interface between augment and metal cup
Hemispherical uncemented implant + structural allograft
- restore bone stock
- can reabsorb
Impaction bone grafting
- morcellized allograft bone impacted into contained defect
- may created a contained defect by inserting mesh
- inserted cemented polyethylene cup
- can use uncemented cup if get press fit
Results
Trabecular metal augments
Xiong et al J Arthroplasty 2023
- systematic review of metal augments in 650 revision THA
- acetabular revision rate 5%
Structural allograft
Cimatti et al J Exp Orthop 2025
- systematic review of structural allograft in revision THA
- failure rate at 8 years: 16%
- structural bone graft + uncemented cup: failure 19%
- structural bone graft + cemented cup: failure 30%
- structural bone graft + antiprotusio cage: failure 12%
Impaction bone grafting
- systematic review of impaction bone grafting using mesh
- failure acetabular component 6%
Zimmer Biomet Trabecular Metal Acetabular Revision system
Cases
Paprosky Type IIB revision to cup with trabecular metal augment
Trabecular metal augments
Paprosky Type IIC revision to mesh + impaction bone grafting + cemented cup
Paprosky Type IIC revision to mesh + impaction bone grafting + cemented cup
Custom acetabular implant
Severe bone loss / Pelvic discontinuity
Pelvic discontinuity
Acetabular revisions options
Cup-cage constructs
- porous metal cup inserted with screws
- ilioischial cage inserted with screws into ilium and ischium
- liner cemented into cage
Custom triflange acetabular component
- Depuy Synthes PINNACLE™ TriFlange Acetabular Cup
- Zimmer Biomet Triflange Acetabular Cup
- custom made based on CT scan
- attaches to ilium / ischium / pubis
Posterior column plating
Acetabular distraction technique
- distract acetabulum using pins in ilium and ischium
- insert oversized porous coated implant into defect
- release distraction
- causes acetabular distraction laterally with some medial compression
- pelvic elasticity provides some stability
Results
Malahias et al J Arthroplasty 2020
- systematic review of revision THA in 570 pelvic discontinuity
- overall survival 85%
- pelvic distraction survival 96%
- custom triflange implant survival 96%
- cup-cage survival 92%
- cup + augment survival 92%
- posterior plate + cup survival 73%
Zimmer Biomet Cup Cage Construct PDF
Zimmer and Depuy Synthes custom triflange acetabular components
Cases
Pelvic discontinuity revised to cup-cage construct
Cup-cage construct
Paprosky Type IIIA with severe bone loss revised to cup cage construct with trabecula metal augment
Cup cage with structural allograft Cup - cage with particular allograft
Impaction bone graft + mesh + cup-cage
Posterior column plating