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Aseptic loosening of Hip Prostheses
Ernesto PintoreClinica Malzoni
Agropoli - Italie
Prosthetic Surgery=
Life quality
AIM OF REVISION SURGERY
• GOOD FUNCTION
• QUALITY OF LIFE
TECHNICALLY DIFFICULT
VARIETY OF IMPLANTS
LEARNING CURVE
INSTRUMENTS
RECENT PROGRESS:
-BIOMATERIALS-DESIGNS-IMPROVED CEMENTING TECHNIQUE-MODULAR PROSTHESES
• SEPTIC LOOSENING
• ASEPTIC LOOSENING
SEPTIC LOOSENING
• CLINIC
• LABORATORY
• X-RAY
• SCINTIGRAPHY
SEPTIC LOOSENING
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
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
ASEPTIC LOOSENING OF THE CUP
• POOR BONE COVERAGE
• MALORIENTATION too vertical, >60°
• POLYETHYLENE FAILURE
• EXCESSIVE HIGHT OF THE CUP >35mm compared to the contralateral
• INADEQUATE CEMENT TECHNIQUE fixation holes and thickness of cement layer
• SMOOTH CUPS and RE-CEMENTED
• THREATED CUPS
X-RAY FEMUR
• VARUS-VALGUS OF THE STEM
• VERTICAL SUBSIDENCE
• HORIZONTAL MIGRATION
• RADIOLUCENCY
• OSTEOLYSIS
• FRACTURE OF THE CEMENT
X-RAY ACETABULUM
• VERTICAL MIGRATION
• HORIZONTAL MIGRATION
• CUP HIGHT
• CUP ANGLE
• RADIOLUCENCY
• OSTEOLYSIS
• POLYETHYLENE FAILURE
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
ACETABULAR BONE STOCK
• CUP MEDIAL TO THE KOHLER’S
LINE (any part of the implant)
• MEDIAL WALL (< 2mm thickness)
• VERTICAL DISTANCE ( > 1 cm between
the line trough the tear drop and the higher
point of the cement layer compared to the
contralateral)
A.A.O.S. Classification
for bone stock damage
• MILD
• MODERATE
• SEVERE
CLINIC
- PAIN
- START UP HECITANCY
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
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.
OPERATIVE TECHNIQUE
• CHOICE OF THE APPROACH
• POSTERO-LATERAL APPROACH
• OSTEOTOMY OF THE TROCHANTER
• FEMORAL “WINDOW”
• WAGNER TECHNIQUE
• REMOVAL OF THE CEMENT
• IMPLANTS
IMPLANTS
• STANDARD STEM
• LONG STEM
• SURFACE
• MODULAR PROSTHESES
• “LOCKING NAIL” PROSTHESES
BONE GRAFT
• AUTOGRAFT
• HOMOGRAFT
• ALLOGRAFTOnly an accurate reconstruction of the
anatomy can allow a good result in the
revision surgery ( Bone bank)
CEMENT OR NOT CEMENT?
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)
CRITERIA FOR DETERMINING BIOLOGIC FIXATION
• BONE INGROWTH
• STABLE BONE-FIBROUS TISSUE
• UNSTABLE IMPLANT
BONE INGROWTH
• NO IMPLANT MIGRATION
• ADAPTIVE REMODELING OF
THE SURROUNDING BONE
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)
CAUSES OF FAILURE
• BAD BONE STOCK
• TROCHANTERIC PROBLEMS
• MISDIAGNOSED PERFORATIONS
• INADEQUATE DESIGN OF THE IMPLANTS
• DYSPLASIC AND NECROTIC HIPS
• INFECTION
• CURVE OF LEARNING
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
COMPLICATIONS
SYSTEMIC COMPLICATIONS
• Urinary infections
• Cardiac problems
• DVT
• Pulmonary embolism
• Blood loss (1000-1500 ml)
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
Aseptic loosening of a Bousquet cup 6 years later
Revision with uncemented cup and auto-homograft
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 longbut despite this we beleavethat this is the surgery wichwe have to develop in the future.
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