This document discusses the history and evolution of total hip arthroplasty (THA) and hip replacement component designs. It outlines key developments from the late 19th century experiments with ivory and tissue replacements, to modern THA pioneered by Professor Charnley in the 1960s using bone cement and low friction materials. Current designs aim to restore normal hip biomechanics and include cemented or cementless femoral and acetabular components with various fixation methods and bearing surfaces to reduce wear. Future advances focus on minimally invasive techniques, computer navigation, and developing more durable and compliant bearing materials to improve implant longevity.
2. The Original Intent of Arthroplasty
was to restore motion to an
ankylosed joint.
Now this concept has been
expanded to include the retoration
as far as possible, of the integrity
and functional power of the
disease joint.
4. HISTORY OF HIP
REPLACEMENT SURGERY
Total hip arthroplasty (THA) has
completely revolutionized the nature
in which the arthritic hip is treated,
and is considered to be one of the
most successful orthopaedic
interventions of its generation.
In 1891, Professor Themistocles
Glück presented the use of ivory to
replace femoral heads of patients
whose hip joints had been destroyed
by tuberculosis.
5. Later, in 1917 William
Baer experimented with
interpositional
arthroplasty, which
involved placing various
tissues (fascia lata, skin,
pig bladders
submucosa) between
articulating hip surfaces
of the arthritic hip
6. In 1925, the American surgeon
Marius Smith-Petersen created the
first mold arthroplasty out of glass.
Later- Backelite and Celluloid
derivatives
1937- Vitallium implants
Vitallium was the first non-reactive
metal alloy to be used in orthopedic
surgery.
7. Professor John Charnley
(1911-1982)
A British Orthopedician, Pioneer of
modern hip replacement
Arthroplasty.
Developed the techniques of THR in
1960s.
It consisted of three parts;
a metal femoral stem, a polyethylene
acetabular component and acrylic
bone cement - which was borrowed
from dentists.
It was called the low friction
arthroplasty as Charnley advocated
the use of a small femoral head
which reduces wear due to its smaller
surface area.
9. The Primary design goal of restoration of
the geometry and bearing quality of the
hip joint leads to recognition that all THR
devices involves 2 primary components.
Femoral and Acetabular.
Each components has 3 elements.
10.
11. Fixation System Design:
Press Fitting: Direct hard tissue apposition.
Goal is to achieve and maintain local tissue stresses
within a range that causes neither atrophy or
necrosis.
Cement: PMMA and its variant is used.
Ingrowth
Adhesion
14. The location of
center of rotation of
femoral head is
determined by
1. Vertical offset
2. Horizontal(medial)
offset
3. Anterior offset
(Anteversion)
15. MEDIAL RESTORATION
IS SIMPLY CORRECTED
BY MAKING NECK
ADJUSTMENT BUT……
LIMB LENGTH INCREASES
16. VERSION
NORMAL FEMUR IS
10 TO 15 DEGREE
ANTEVERTED.
USUALLY
ACCOMPLISHED BY
ROTATING THE
COMPONENT IN
FEMORAL CANAL.
IF PRESS FIT
FIXATION IS USED –
MODULAR
FEMORAL
COMPONENT IS
USED.
17. HEAD NECK RATIO
AFFECTS ROM ,IMPINGEMENT,STABILITY OF ARTICULATION.
18. Large Head size
Increased ROM
Decreased
Impingement
Less chances of
Dislocation
Less wear
More stability
Small Head size
Decreased ROM
Impingement is more
More chances of
dislocation
More wear
Less stability
19. TYPES OF FEMORAL COMPONENTS
The Femoral Component Replaces the natural femoral head portion or all of the femoral neck and bony elements in the proximal femur between Greater and lesser trochanters.
Cemented stems Cementless stems
porous surface
nonporous surface Specialized custom-made
20. CEMENTED STEMS
Most designers favour- cobalt chrome alloy
PMMA cement is the standard for
femoral component fixation
Disadvantages- Debonding,
Mechanical loosening, Extensive bone loss with
fragmented cement
Earlier the original Charnley’s component was
about 13 cm long. But current stem design ranges
from 120-150mm.
25. 2. Cementless stems with porous surface
Fixation is more biological.
Material- titanium alloy/ Cobalt-Chromium alloy
Bone ingrowth into porous metal surface
Requires: a)immediate mechanical stability at
the time of surgery
b) intimate contact between porous
surface and viable host bone
So, surgical technique and instrumentation
need to be more precise than cemented
counterpart
26. There are 6 types of Cementless
femoral components.
Type I – Type V are straight stems
and fixation area increases with
type.
Type VI is anatomical
27. Type 1:
Single Wedge stem
Flat in AP plane and
tapered in Medio-
lateral Plane.
Fixation is by cortical
Engangement in
Medio-lateral plane
and 3 bony point
fixation.
28. Type 2:
Dual Wedge stem
Engages in AP
and Medio-lateral
Planes.
29. Type 3:
Implant
tapered in 2
planes but
fixation is
achieved more
at the meta-
physial
diaphysial
junction than
proximally.
30. Type 4:
Extensively Coated
Implant with Fixation
along The entire
length of the stem.
31. Type 5:
Modular Stem,
Separate Meta-Physial
sleeve and diaphysial
segment that are
independentaly sized
and instrumented.
32. Type 6:
Anatomical Femoral
Component incorporate
posterior bow in
metaphysial portion and
anterior bow in diaphysial
portion corresponding to
the geometry of femoral
canal.
37. Constrained acetabular components
Mechanism to lock the
prosthetic femoral head into the
polythene liner
Indications-
-Insufficient soft tissue,
-Deficient hip abductors,
-Neuromuscular disease,
-Hip with recurrent
dislocation despite well-
positioned implants.
38. Alternative bearings(evolution)
Ivory Femoral Head
Baer’s Membrane
Mould Arthroplasty- Glass, Bakelite,
vitallium.
Metal on metal bearings
Highly cross linked polyethylene
Ceramic on ceramic bearings
39. Ideal bearing surface
1. Low coefficient of friction
2. Small volume of wear particle generation
3. Low tissue reaction to wear particles
4. High resistance to third body wear
5. Enough deformation of articular surfaces
to permit adequate fluid film lubrication
during the stance phase without
increasing wear
40. Metal on metal bearings
Low wear rate
High carbon cobalt chromium
alloy
Diametral clearance-gap between
the two implants at the equator of
articulation.
Smaller clearance produce films
for lubrication and reduced wear.
Elevated metal ions in blood that
excreted through urine.
41. So contraindicated in impending renal failure.
Placental transfer occur of these metal ions.
Delayed type hypersensitivity (aseptic
lymphocytic vasculitis associated lesions)
Pseudotumour
Recommendation for symptomatic patients is
measurement of blood cobalt and chromium ion
level and/MRI or USG.
42. CERAMIC ON CERAMIC
BEARINGS
ALUMINA CERAMIC IS USED.
HIGH DENSITY, HYDROPHILLIC,
SMOOTHER THAN METAL.
CERAMIC IS HARDER THAN
METAL AND MORE RESISTANT TO
SCRATCHING.
LINEAR WEAR RATE IS 4000 TIME
LESS THAN COBALT CHROME
ALLOY ON POLYETHYLENE.
46. Compliant bearings
Cartilage is an example of a compliant bearing
that has a low modulus but is capable of large
deformation without failure.
Polyurethanes are synthetic polymers having
properties comparable to those of articular
cartilage.
Extensive laboratory and mechanical studies have
been underway over the last decade to
determine suitability of polyurethanes as a bearing
surface aimed at obtaining a bearing surface
couple in which the surfaces are separated by
pressure developed in joint fluid as well as by
deformation of articular surfaces.
47. Future Advances in THR
Minimally invasive surgery :
Gaining popularity in
recent years, minimally
invasive techniques are
currently being developed.
The use of a single-incision,
less than 10 cm in length
using conventional surgical
approaches, provides soft-
tissue sparing and bone
conservation options.
48. Computer-assisted surgery :
Computer-assisted total hip
replacement utilizes digital image
systems to map the position of
surgical instruments in relation to
anatomical landmarks, helping to
obtain reproducible and accurate
placement of implants. Computer
navigation may improve the
accuracy of prosthesis positioning
but, despite its obvious advantage
with respects to reducing
asymmetric wear, this has not yet
been shown to have a clinical
benefit.
49. Since the first total hip arthroplasty in 1891,
research has developed from perfecting
surgical technique to advances in technology
(with respects to both prosthesis design and
materials) in order to provide a reproducible
technique that provides a good range of
motion, stability and most importantly
adequate life span.
As the average age of those receiving hip
Arthroplasty decreases, such considerations will
continue to be of great value to increase
implant longevity in highly active patients.
Femoral: An element to restore articulating surface property and the geometry of femoral head (Articulation element).
An Element to anchor the restored surface of proximal femur (Fixation element).
An Element to couple the articulation element and the fixation element and to maintain an appropriate structural relationship between them (Structural element).
Acetabular: An element to restore the articulating surface property and geometry of acetabular socket( Articulation element).
An element to anchor the restore surface to the peri-acetabular pelvis (Fixation element)
An Element to couple the articulation element and the fixation element and to maintain an appropriate structural relationship between them (Structural element).
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A pseudotumor is a non-cancerous soft tissue growth that occurs when metal particles from a metal-on-metal hip implant irritate tissue in the hip. Pseudotumors do not always cause problems, but when they do, severe pain and inflammation in the hip often requires a revision surgery to correct.
Metal-on-metal pseudotumours are large focal solid or semiliquid masses around the hip (or knee) prostheses. The pseudotumours mimic local effects of neoplasia or infection in the absence of either of these. The principal symptom is pain. There may be restricted range of movement with large pseudotumours.
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