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Total Hip Replacement: Implant Choices

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Socket or acetabulum holds the ball. Hip Replacement Components ... Larger cups and liners that may require the removal of excess healthy acetabulum bone ... – PowerPoint PPT presentation

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Title: Total Hip Replacement: Implant Choices


1
Total Hip Replacement Implant Choices
2
Introduction
  • Improvements in durability and compatibility of
    materials for hip replacements
  • New designs to help patients of any age
  • Choices of hip joint materials
  • Metal-on-polyethylene
  • Metal-on-metal
  • Ceramic-on-ceramic
  • Ceramic-on-polyethylene

3
Total Hip Replacement
  • The goal is to reduce hip pain and improve the
    motion in your hip.
  • More than 345,000 people in the United States
    annually undergo hip replacement surgery.

4
Anatomy of the Hip
  • Ball and socket joint
  • Femoral head or ball is at the end of thighbone
    or femur.
  • Socket or acetabulum holds the ball.

5
Hip Replacement Components
  • Acetabular component - consists of two components
  • Cup - usually made of titanium
  • Liner - can be medical grade plastic, metal or
    ceramic

Cup
Liner
6
Hip Replacement Components
  • The femoral component (stem and neck portion), is
    made of metal.
  • Femoral head is made either of metal or ceramic.
  • Stem is shaped to fit into the bone and support
    the new joint.

Head
Neck
Stem
7
Choosing an Implant Right for You Important
Factors to Consider
  • Range of Motion
  • Stability
  • Wear resistance
  • Lifestyle
  • Gender
  • Age
  • Weight
  • Severity of Osteoarthritis disease

8
Range-of-Motion(ROM) What is it? Why is it
Important?
  • Arc created by bending the limb at the joint
    called flexion
  • Allows thigh to flex from 0 to 90 degrees
  • Flexion beyond 90 degrees can cause dislocation

9
Stability What is it?Why is it Important?
  • Amount of resistance to forces causing motion or
    change of position
  • Ligaments and muscles create a resistance force
    keeping the ball of the thighbone in contact with
    the hip socket
  • Stability is the mechanical goal of the implant.

10
Implant Stability
  • Flexing beyond 90 degrees may bring the femoral
    neck against the rim of the cup causing
    impingement
  • Femoral ball could leave the cup and dislocate

11
How to Improve Hip Stability
  • Implants with large diameter ball components
    (36mm or greater) provide more stability
  • Allows flexion above 90 degrees without
    impingement

12
What are Possible Side Effects?
  • Larger cups and liners that may require the
    removal of excess healthy acetabulum bone

13
Wear What is it? Why is it Important?
  • Similar to erosion
  • Caused by friction between the femoral head and
    acetabular cup
  • May result in particles flaking off
  • Immune system attacks particles and potentially
    bone, causing osteolysis
  • Implant may loosen and function improperly

14
Hip Implant Bearing Materials
  • The bearing is the union of the ball and socket.
  • Bearings are made from a variety of commercially
    available materials.

15
Hip Implant Bearing Materials
  • Metal-on-Polyethylene (poly)
  • traditional bearing
  • Poly cup with a metal ball
  • Metal-on-Metal
  • All metal ball and cup
  • Ceramic-on-Polyethylene (poly)
  • Poly cup with a ceramic ball
  • Ceramic-on-Ceramic
  • Ceramic cup and ball

16
Metal-on- Polyethylene Implants
17
Metal-on-Poly Overview
  • Poly acts as a cushion for the joint
  • Shell made of titanium alloy
  • Cup made of medical grade cross-linked
    polyethylene
  • Long clinical history since 1963
  • Not toxic to the body

18
Metal-on-Poly Overview
  • Inappropriate for patients who recently or
    currently have
  • Joint sepsis (infection)
  • Insufficient bone stock
  • Marked atrophy (weakness)
  • Upper femur deformity
  • Skeletal immaturity

19
Metal-on-Poly Range of Motion
  • Wide range of motion up to 90 degrees flexion
  • Options available for patients with
  • Smaller bone structure
  • Smaller stature
  • Abnormal hip structure

20
Metal-on-Poly Stability
  • Accommodate different sizes of femoral heads
  • Control over customization of the implant and fit
    in the body
  • Increased cup options to optimize joint stability
  • Precise insertion, increasing stability

21
Metal-on-Poly Wear
  • All bearing surfaces wear with time
  • Marathon Cross Linked Polyethylene from DePuy,
    exhibits 86 wear reduction vs. traditional
    polyethylene in mechanical tests

Wear Rates Marathon vs. Traditional Poly
Traditional Polyethylene
Marathon Cross Linked Polyethylene from DePuy
22
Metal-on-Metal Implants
23
Metal-on-Metal Overview
  • Ball and liner made of high-standard,
    surgical-grade cobalt chromium alloys
  • Not toxic to the body
  • Available since 1960s

24
Metal-on-Metal Overview
  • Appropriate patients may have
  • Young and active lifestyle
  • Rheumatoid arthritis
  • Osteoarthritis
  • Post-traumatic arthritis
  • Collagen disorders
  • Avascular necrosis
  • Non-union of femoral fractures

25
Metal-on-Metal Overview Cont.
  • Inappropriate for patients who recently or
    currently have
  • Joint sepsis (infection)
  • Insufficient bone stock
  • Marked atrophy (weakness)
  • Upper femur deformity
  • Skeletal immaturity

26
Metal-on-Metal Overview Cont.
  • Metal-on-metal femoral heads offer
  • Low wear
  • Resistance from corrosion and wear
  • Excellent clinical history- over 100,000
    implanted
  • Increased range of motion
  • Very hard and resistant to chipping or cracking
  • Smaller diameter acetabular designs to conserve
    healthy bone

27
Metal-on-Metal Range of Motion and Stability
  • Available in large diameter femoral balls (36mm
    or greater)
  • Greater range of motion (up to 151 degrees)
  • Increased stability
  • Lower rate of dislocation

28
Metal-on-Metal Wear
Wear Rate Metal vs. Polyethylene
  • Wear rates up to 100 times less than
    metal-on-poly bearings in mechanical tests

Traditional Polyethylene
Ultamet Metal on Metal Articulation from DePuy
29
Ceramic-on-PolyethyleneImplants
30
Ceramic-on-Poly Overview
  • Cup made of Marathon cross-linked poly
  • Ball made of Biolox Delta Ceramic
  • Composite zirconia aluminum ceramic

31
Ceramic-on-Poly Overview cont.
  • Appropriate patients may have
  • Rheumatoid arthritis
  • Osteoarthritis
  • Post-traumatic arthritis
  • Collagen disorders
  • Avascular necrosis
  • Non-union femoral fracture

32
Ceramic-on-Poly Overview cont.
  • Inappropriate for patients who recently or
    currently have
  • Joint sepsis (infection)
  • Insufficient bone stock
  • Marked atrophy (weakness)
  • Upper femur deformity
  • Skeletal immaturity

33
Ceramic-on-Poly Range of Motion and Stability
  • Available with large diameter femoral ball (36mm
    or greater)
  • Greater range of motion (up to 151 degrees)
  • Multiple liner options to reduce the potential
    for dislocation

34
Ceramic-on-Poly Wear
Fracture toughnessBiolox Delta vs. Alumina
  • Marathon Highly Cross Linked Polyethylene
    exhibits 86 wear reduction over standard poly
    liners in mechanical test
  • Biolox Delta Ceramic Ball resistant to chipping
    or cracking
  • 97 tougher than traditional alumina ceramics in
    mechanical tests
  • Smoother femoral ball decreases wear potential

Biolox Delta from DePuy
Conventional Alumina Ceramics
35
Ceramic-on-Ceramic Implants
36
Ceramic-on-Ceramic Overview
  • Ball and cup made of alumina ceramic
  • Shorter clinical history
  • Not toxic to the body

Not currently available from DePuy Orthopaedics.
37
Ceramic-on-Ceramic Overview cont.
  • Ceramic femoral heads offer
  • Excellent compatibility within the body
  • Good mechanical performance
  • Very hard and scratch-resistant
  • Chemical and temperature stability

38
Ceramic-on-Ceramic Overview cont.
  • Appropriate patients may have
  • Young and active lifestyle
  • Rheumatoid arthritis
  • Osteoarthritis
  • Post-traumatic arthritis
  • Collagen disorders
  • Avascular necrosis
  • Non-union of femoral fractures

39
Ceramic-on-Ceramic Overview cont.
  • Inappropriate for patients who recently or
    currently have
  • Joint sepsis (infection)
  • Insufficient bone stock
  • Marked atrophy (weakness)
  • Upper femur deformity
  • Skeletal immaturity
  • Osteoporosis

40
Ceramic-on-Ceramic Range of Motion
  • Large diameter femoral balls
  • Reduced range of motion (133 degrees)
  • Increased stability
  • Larger diameter femoral balls require larger
    diameter acetabular shells
  • 36mm ball requires a 58mm shell

41
Ceramic-on-Ceramic Stability
  • Intolerance to any impingement of the neck
    against rim of the cup.
  • Emphasis on correct implant placement, especially
    in younger patients
  • Potential for neck and rim impingement with
    reduced range of motion
  • Severe impingement may cause a fracture,
    requiring revision surgery

42
Ceramic-on-Ceramic Wear
  • 100-200 times less wear rate than other materials
    in mechanical tests
  • Resistance to deformation and surface scratching
  • Less particle debris around joint available to
    get into the body

43
Bearing Summary - Choices
  • Surgeons choose a bearing based on durability,
    level of performance, wear resistance and your
    personal needs.
  • All of todays bearing materials offer the
    potential for excellent performance.
  • No one material is right for every patient.
  • Only your surgeon can determine whats right for
    you.
  • And whats right for you may not be right for the
    next patient!

44
Benefits to Patient from Surgery
  • Return to Mobility
  • Restores lifestyle
  • Freedom

45
Potential Complications and Risks
  • Individual results may vary
  • There are potential risks and recovery can take
    time.
  • The performance of any new joint will depend on
    your weight, activity level, age and other
    factors.

46
Questions?
  • Thank You!
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