KnotesFree Orthopaedic & FRCS notes, viva stations and higher order SBAs

Revision THA

Must KnowHipthinKbox SBA

Goals

  • Removal of loose components with out destroying bone and soft tissue
  • Reconstruct bone defect
  • Stable fixation of implants
  • Restore normal hip centre of rotation

Indications

  • Instability
  • Periprosthetic Fracture
  • Infection
  • Aseptic loosening
  • ARMD

C/I

  • Referred pain
  • Cause not known
  • Medically unfit
  • Painless LOM
  • Painless LLD

Acetabular reconstruction

  • AAOS Classification
    • Segmental: loss of perepheral/medial wall
    • Cavitatory: Volumetric loss of bone from cavity
    • Combined
    • Pelvic discontinuity
    • Arthrodesis

Paprosky

  • I: no cup migration/minimal bone loss

  • IIA: Superior/superomedial migration <3cm

  • IIB: superior/superolateral migration <3cm

  • IIC: Medial wall defect

    • Cup medial to kohler line
  • IIIA Superolateral migration

    • moderate ischial lysis
    • Partial tear drop destruction
    • Kohler line intact
  • IIIB: Superomedial migration

    • Severe ischial lysis
    • No tear drop
    • Migration medial to kohler line
  • Migration of component

  • Ischeal lysis

  • Lysis of tear drop

  • Kohler line

  • I: completely supportive

    • No migration, rim intact
  • II: Partly supportive

    • Ac/PC intact
    • Migration present
    • Some destruction of dome/medial wall
    • IIA: Lateral Rim is intact (cavitatory)
    • IIB: Lateral Rim absent (segmental)
    • IIC: Localised medial wall destruction
  • III: Un supportive

    • Ischeal lysis
    • Tear drop lysis
    • Kohler line breached

Reconstruction options

  • Liner exchange
  • Cavitatory
    • Uncemented hemispherical tantalum/ titanium cup +/- BG
  • Segmental loss
    • Bulk allograft
    • Metal augments
  • Massive bone loss/discontinuity
    • Cage
    • triflange cup

Femoral bone loss

  • AAOS
    • Segmental
    • Cavitatory
    • Combined
    • Stenosis
    • Discontinuity

Paprosky

  • Based on metaphyseal and diaphyseal bone loss
  • I:Minimal M/Normal D
  • II:Extensive M bone loss/Normal D
  • IIIA:Metaphysis severely damaged/>4cm D present
  • IIIC: M severely damaged/<4cm D present (isthmus supportive)
  • IV: Isthmus non supportive

Implant options

  • Proximally loaded porous coated
  • Extensive porous coated
  • Distal locking stem
  • Mega prosthesis
  • Allograft-prosthesis composite

Impaction bone grafting

  • Crouton size particle BG

Written/reviewed by Kishore Puthezhath

Professor of Orthopaedics and Consultant Paediatric Orthopaedic Surgeon

FRCS (Tr & Orth) revision resource

Reviewed: September 2026