Aseptic loosening of Hip Prostheses

1
Aseptic loosening of Hip Prostheses

• Ernesto Pintore
• Clinica Malzoni
• Agropoli - Italie

2
Prosthetic SurgeryLife quality
3
AIM OF REVISION SURGERY

• GOOD FUNCTION
• QUALITY OF LIFE

4
TECHNICALLY DIFFICULT VARIETY OF
IMPLANTS LEARNING CURVE INSTRUMENTS
5
RECENT PROGRESS -BIOMATERIALS -DESIGNS -IMPROVE
D CEMENTING TECHNIQUE -MODULAR PROSTHESES
6

• SEPTIC LOOSENING
• ASEPTIC LOOSENING

7
SEPTIC LOOSENING

• CLINIC
• LABORATORY
• X-RAY
• SCINTIGRAPHY

8
SEPTIC LOOSENING
9
ASEPTIC LOOSENING

• MECHANICAL FAILURE
• Aseptic loosening of one or both components,
  fracture of a component, recurrent dislocation of
  the hip, fracture of the femoral shaft.
• Callaghan JJ Salvati E.A. et al.
• JBJS 1985

10
ASEPTIC LOOSENING OF THE FEMUR

• MALPOSITION OF THE STEM
• FRACTURE OF THE IMPLANT
• FRACTURE OF THE FEMUR
• RECURRENT DISLOCATION
• INADEQUATE STEM DESIGN
• INADEQUATE CEMENTING TECHNIQUE
• INADEQUATE CEMENT LAYER

11
ASEPTIC LOOSENING OF THE CUP

• POOR BONE COVERAGE
• MALORIENTATION too vertical, gt60
• POLYETHYLENE FAILURE
• EXCESSIVE HIGHT OF THE CUP gt35mm compared to the
  contralateral
• INADEQUATE CEMENT TECHNIQUE fixation holes and
  thickness of cement layer
• SMOOTH CUPS and RE-CEMENTED
• THREATED CUPS

12
X-RAY FEMUR

• VARUS-VALGUS OF THE STEM
• VERTICAL SUBSIDENCE
• HORIZONTAL MIGRATION
• RADIOLUCENCY
• OSTEOLYSIS
• FRACTURE OF THE CEMENT

13
X-RAY ACETABULUM

• VERTICAL MIGRATION
• HORIZONTAL MIGRATION
• CUP HIGHT
• CUP ANGLE
• RADIOLUCENCY
• OSTEOLYSIS
• POLYETHYLENE FAILURE

14
FEMORAL BONE STOCK

• Poor if the thickness of either aspect of the
  cortex on the AP x-ray had decreased by 50,
  along a 10 cm segment of femoral stem, compared
  with the original arthroplasty, or if the
  thickness of both aspect of the cortex had
  decreased this amount along a 5 cm segment

15
ACETABULAR BONE STOCK

• CUP MEDIAL TO THE KOHLERS LINE (any part of the
  implant)
• MEDIAL WALL (lt 2mm thickness)
• VERTICAL DISTANCE ( gt 1 cm between the line
  trough the tear drop and the higher point of the
  cement layer compared to the contralateral)

16
A.A.O.S. Classification for bone stock damage

• MILD
• MODERATE
• SEVERE

17
CLINIC

• - PAIN
• - START UP HECITANCY

18
DEFINITION OF ACETABULAR LOOSENING(Harris and Mc
Gunn JBJS 1986)

• DEFINITE LOOSENING
• change of position of the implant, or cement.
• fracture of the cement
• radiolucency at the cement-implant interface
• PROBABLE LOOSENING
• no migration or change of position
• continuous radiolucency (100) at cement-bone
• interface
• POSSIBLE LOOSENING
• radiolucency 50-99 at the cement-bone
  interface

19
WEAR DEBRIS

• The wear debris is responsible of a local
  inflammatory reaction with histyocytes and mast
  cells proliferation, that leads to osteolysis and
  loosening of the implant.

20
OPERATIVE TECHNIQUE

• CHOICE OF THE APPROACH
• POSTERO-LATERAL APPROACH
• OSTEOTOMY OF THE TROCHANTER
• FEMORAL WINDOW
• WAGNER TECHNIQUE
• REMOVAL OF THE CEMENT
• IMPLANTS

21
IMPLANTS

• STANDARD STEM
• LONG STEM
• SURFACE
• MODULAR PROSTHESES
• LOCKING NAIL PROSTHESES

22
BONE GRAFT

• AUTOGRAFT
• HOMOGRAFT
• ALLOGRAFT
• Only an accurate reconstruction of the
• anatomy can allow a good result in the
• revision surgery ( Bone bank)

23
CEMENT OR NOT CEMENT?
24
ALTHOUGH MODIFICATION AND IMPROVING OF
CEMENTING TECHNIQUE HAVE DECREASED THE
INCIDENCE OF FEMORAL AND ACETABULAR
LOOSENING IN THR, THRE IS NO EVIDENCE
DEMONSTRATING BENEFITS IN REVISION SURGERY
WITH THE CEMENT. Engh C. Glassman
A. (Instructional course lecture 1991)
25
CRITERIA FOR DETERMINING BIOLOGIC FIXATION

• BONE INGROWTH
• STABLE BONE-FIBROUS TISSUE
• UNSTABLE IMPLANT

26
BONE INGROWTH

• NO IMPLANT MIGRATION
• ADAPTIVE REMODELING OF THE SURROUNDING BONE

27
CAUSES OF SUCCESS IN FEMORAL REVISION

• FRESHENING THE BONE
• RESTORE THE BONE STOCK
• IMPROVED TROCHANTERIC FIX.
• TREATEMENT OF PERFORATIONS
• ADEQUATE STEM
• -Extensevely porous coated
• -Design (filling)

28
CAUSES OF FAILURE

• BAD BONE STOCK
• TROCHANTERIC PROBLEMS
• MISDIAGNOSED PERFORATIONS
• INADEQUATE DESIGN OF THE IMPLANTS
• DYSPLASIC AND NECROTIC HIPS
• INFECTION
• CURVE OF LEARNING

29
RESULTS OF UNCEMENTED REVISIONS (C.
Engh - A. Glassman)

• 163 hips
• 80,7 of bone ingrowth
• 12,3 of stable fibrous tissue
• 3,5 unstable implants re-revised

30
COMPLICATIONS

• SYSTEMIC COMPLICATIONS
• Urinary infections
• Cardiac problems
• DVT
• Pulmonary embolism
• Blood loss (1000-1500 ml)

31
LOCAL COMPLICATIONS

• Superficial and deep infections
• Trochanteric nonunion (10)
• Trochanteric problems
• Fracture of the femur
• Perforation of the femur
• Fracture of the pelvis
• Recurrent dislocations (9-12)
• Ectopic bone

32
Aseptic loosening of a Bousquet cup 6 years later
33
Revision with uncemented cup and auto-homograft
34
Revision surgery is technically difficult and
requires an experienced surgeon and economic
means to achieve the most performant
devices. There are many complications and the
results are not always good. The learning curve
is long but despite this we beleave that this is
the surgery wich we have to develop in the
future.