Revision Total Hip Replacement (THR): Surgical Principles, Techniques, and Bone Defect Management in Complex Hip Arthroplasty Cases”
- 1. REVISION THR -DR.PRABHAT PANDEY DNB RESIDENT ORTHOPEDICS TATA MAIN HOSPITAL
- 2. Introduction: • More difficult • Not as satisfactory as after a primary THR • More operative time and blood loss • Incidences-Infection,thromboembolism,dislocation,nerve palsy, and fracture of the femur are higher • Already weakened bone stock • Implant removal • Inadequate soft tissue envelopes • Intramedullary hardware removal
- 3. Indications: • Dislocation • Mechanical loosening • Other mechanical problems • Infection • Osteolysis • Periprosthetic fracture • Wear • Implant failure or breakage • Painful loosening
- 4. PRINCIPLES OF REVISION THR • Removal of loose components • Limit destruction of host bone/soft tissue • Reconstruction of bone defects by metal/bone graft • Stability of revision components • Restoration of normal hip centre of rotation(biomechanics) and a stable joint.
- 5. DISLOCATION(Instability) • Occurs after 0.3% to 10% of primary THR • Upto 28% of revision thr • Risks is influenced by the surgical approach,the underlying diagnosis,the surgical technique,implant positioning,abductor insufficiency,the life time-of the prosthesis and the patient’s compliance with restrictions
- 6. Surgical approach: • Posterolateral-highest risk but excellent exposure of the acetabulum. • Hardinge-safer as compared to posterolateral but inadequate exposure and risk of abductor lurch. • Direct anterior approach-minimal invasive(no muscle cutting),least risk,Disad- steep learning curve and risk of femur fracture(femur preparation-difficult)
- 7. Underlying diagnosis • Fracture neck femur • Associated neurological conditions • Spinal deformity,degenerative conditions
- 8. • Component positioning and abductor insufficiency are the two most important reconginized causes of recurrent dislocation • When malpositioning is the cause,revision of the component is the most effective type of surgical intervention
- 9. • EARLY DISLOCATION-early post-operative period(within 6 months),often treated non-operative means • LATE DISLOCATION-occurs after 5 years and generally requires surgical treatment • INTERMEDIATE DISLOCATION-between 6th months and five years.
- 10. Preoperative planning • High-quality radiographs-pelvis and entire femur and AP and lateral views. • Ct scan-acetabular deficiencies. • Routine blood investigations,CBC,ESR,CRP (Most important step-always rule out infection) • VERSION of the components can’t be assessed on xrays • CT is needed to more accurately assess component positioning, especially with regard to version of the acetabulum.
- 11. Surgical options available: • Component revision • Modular component exchange bipolar arthroplasty • Use of a larger femoral head • Soft-tissue reinforcement • Advancement of the GT • Use of a constrained liner.
- 12. Operative exposure • Standard extensile posterolateral or hardinge approach based on pervious incision • After deep exposure,scar and pseudocapsule is excised and femur is mobilized • If the femur component is modular,head and liner are removed • If the femur component is planned for revision,it should be removed for acetabular exposure
- 13. Cemented femoral component • Removal of cemented femoral component • Can tap on the collar of the implant to push it out
- 15. Removal of cement • Fiberoptic light source • Straight suction catheter • Moreland cement removal set • (long osteotomes,hooks,curettes) • Burr • reamers
- 18. Removal of cementless femoral component
- 21. Removal of cemented cup
- 23. Deficiency of acetabular bone stock • Major problems in revision THA
- 24. Paprosky classification of acetabular bone loss • 1994 • It is based on the severity of acetabular bone loss and the ability to obtain a cementless fixation for a given bone loss • 3 main types and further have subtypes.
- 25. 4 components: • Teardrop • Hip centre migration • kohler’s line • Presence or absence of ischial lysis
- 26. Type 1 • Localized bone lysis
- 27. Type 2 • They have deficient acetabular walls with intact acetabular columns and less than 2cm of hip centre migration • Type II defects are divided into 3 subclasses better based on the location of the defect and the resultant direction of the acetabular component migration • <50% cancellous bone in the bone bed of the acetabulum.
- 28. TYPE 2A • Less than 2 cm superomedial migration-Hip centre • Teardrop-Intact • Kohler’s line-Intact • Ischium(posterior column)-intact • It is enlarged superiorly to create an oval.
- 29. TYPE 2B • Teardrop(medial wall)-Intact • Hip centre migration-<2cm superolateral • Absent superior dome to the acetabulum, this will allow for superior and lateral acetabular component migration as the superior rim acts as a laterally supporting buttress to the component • The superior rim is absent;however, the column remains fully supportive • Kohler’s line and ischium -intact
- 30. TYPE 2C • Teardrop(medial wall)-moderate lysis • Absent teardrop resulting in medial migration of the acetabular component(less than 2cm) • The superior dome is intact which will prevent any superior displacement The rim is enlarged and the medial wall Is destroyed. The teardrop may be Obliterated as well.
- 31. TYPE 3 • Hallmark-is an unsupportive rim • Greater than 2cm of hip centre migration • And loss of supporting structures of the acetabulum • These defects may be associated with pelvic discontinuity • 2 subtypes
- 32. TYPE 3A • Moderate lysis of the teardrop and ischium(posterior column) • Kohler’s line-remain intact • Hip centre migration greater than 2cm in the superolateral direction • 30%-60% of component supported by graft • Bone loss:10 o’clock to 2 o’ clock position.
- 33. TYPE 3B • Greater than 2cm of superior medial migration-hip centre • Loss of all supporting acetabular structures • including both walls and both columns. • Severe lysis of medial wall(tear drop) and ischium(posterior column) • Kohler’s line-disrupted • Bone loss- 9-5 ‘ o clock • >60% of component supported by graft
- 35. Management of bone acetabulum defects Reconstruction options • Elliptical cup • Jumbo cup • With multihole hole • With peripheral screw hole • Metal augments