2. General Anatomical Overview
The hip is one of your body's largest weight-bearing
joints.
Consists of two main parts:
a ball (femoral head) that fits into a rounded socket
(acetabulum) in your pelvis.
Ligaments connect the ball to the socket and
provide stability to the joint
The bone surfaces of your ball and socket have a
smooth durable cover of articular cartilage that
cushions the ends of the bones and enables them to
move easily.
4. More…
All remaining surfaces of the hip joint are covered
by a thin, smooth tissue called synovial membrane.
In a healthy hip, this membrane makes a small
amount of fluid that lubricates and almost
eliminates friction in your hip joint.
Normally, all of these parts of your hip work in
harmony, allowing you to move easily and without
pain.
5. Total Hip Replacement
A prosthetic hip that is implanted in a similar
fashion as is done in people. It replaces the
painful arthritic joint.
The modular prosthetic hip replacement system
used today has three components – the femoral
stem, the femoral head, and the acetabulum.
Each component has multiple sizes which allow
for a custom fit.
The components are made of cobalt chrome
stainless steel and ultra high molecular weight
polyethylene. Cementless and cemented
prosthesis systems are available.
6. Objective Assessment
Gait pattern – Adaptive walking pattern that
reduces pressure on the affected side.
Muscle atrophy – Muscles in affected area are not
used as much due to pain, therefore, use-it-or-lose-
it applies.
Active Range Of Motion – Limited ROM, stiffness
Passive ROM – End feels causes severe pain
X-ray – clear degeneration of the bone
MRI – determines underlying complications
(e.g.avascular necrosis)
7. INDICATIONS FOR THA :
The primary indication for THA is incapacitating PAIN.
Pain in the hip in the presence of destructive process as
evidenced by X-ray changes is an indication.
THA is an option for nearly all patients with diseases of the
hip that cause chronic discomfort and significant functional
impairment.
Patients with limitation of movement, leg length inequality
and limp but with little or no pain are not the candidates for
THR.
8. Rheumatoid arthritis
Osteo arthritis
Primary
Secondary – Perthe’s, trauatic dislocation, Paget’s disease etc.
Ankylosing spondylitis
Avascular necrosis of femoral head.
Congenital subluxation or dislocation
Pyogenic arthritis and TB arthritis
Non union of fracture of femoral neck.
Failed Hip fusion and pseudarthrosis
Failed reconstruction
Osteotomy
Cup arthroplasty
Femoral head prosthesis
Girdle stone arthroplasty
Resurfacing arthroplasty
Bone tumor involving proximal femur or acetabulum
Hereditary disorders viz : Achondroplasia
9. CONTRAINDICATIONS :
Absolute
a) Patient with unstable medical illness that would
significantly increase the risk of morbidity and
mortality.
b) Active infection of the hip joint or anywhere else
in the body.
Relative
Any process that is rapidly destroying bone eg.
neuropathic joint, generalized progressive
osteopenia.
Insufficiency of abductor musculature.
Progressive neurological disorder.
10.
11. FEMORAL COMPONENTS :
Neck length and offsets :
The ideal femoral reconstruction reproduces the
normal center of rotation of femoral head, which can
be determined by
Vertical height of the femoral head : measured from
LT to center of the femoral head. Restoration of this
distance is essential in correction of leg length.
Medial head stem offset : distance from the center of
the femoral head to a line through the axis of the distal
part of stem. Inadequate restoration of this offset
shortens the moment arm of the abductor musculature
and results in increased JRF and limping, conversely
excessive increase produces increased stresses within
the stem that may lead to stem fracture or femoral
loosening.
Version of the femoral neck : Restoration of the
femoral neck anteversion is important in achieving
stability of the prosthetic joint. The normal femur has
10-15 degree of anteversion.
12. Femoral components are of three general types :
Cemented
Cementless with porous surface
Cementless press-fit variety
13. The stem fabricated of high strength super alloy (Cobalt
– Chrome )has been favoured by some designers
because of its higher modulus of elasticity, may decrease
stresses within the proximal cement mantle.
The cross section of the stem should have broad medial
and lateral border to load the proximal cement mantle
in compression.
Sharp edges should be avoided. .
The bond between prosthesis and the cement is
improved by surface macrotexturing .
A collar aids in determining depth of insertion and
may diminish resorption of bone in the medial neck.
FEMORAL COMPONENTS USED WITH CEMENTFEMORAL COMPONENTS USED WITH CEMENT
14. Non circular shapes, longitudinal grooves give
rotational stability.
Stems should occupy 80% of the cross section of the
medullary canal with cement mantle of 4 mm
proximally,2mm distally.
Proximal and distal PMMA centralizers to give
uniform cement mantle around the stem and neutral
placement of stem.
Range of head sizes – 22, 26, 28 & 32 mm.
Incidence of dislocation is higher for smaller head.
Neck diameter : Original charnleys was 12.5 mm but
has been reduced to 10.5 mm – reduced neck diameter
avoids impingement during flexion and abduction.
Range of stem lengths -120 mm to 170 mm.
The main problem is mechanical loosening and
extensive bone loss associated with fragmented
cement
15. CEMENTLESS STEMS WITH POROUS SURFACES
Currently available porous coated stress designs are
made up of :
Titanium – vanadium-aluminum alloy with porous surfaces of
pure titanium fibre mesh or beads.
Cobalt – chromium alloy with sintered beaded surface.
The advantages of cementless femoral stem prosthesis :
No cement is required and problems related to cement are
eliminated.
Applicability in young and active patients and in revision THR.
Circumferential porous coating of proximal stem provides more
effective barrier to ingress of particle and thus limits early
development of osteolysis in distal stem
Decreased incidence of aseptic loosening.
Less bone destruction.
16. Two pre-requisites for bone in growth in porous
coated stem are
Immediate implant stability.
Intimate contact between implant and bone in
endosteal cavity of the proximal femur.
17. NON POROUS CEMENTLESS FEMORAL COMPONENTS
With the concerns about fatigue strength, ion
release and adverse femoral remodeling, these non
porous stems came into use over porous stems.
These devices have groove and other surface
modifications that provide a macro interlock with
bone, but have no other capacity for biologic fixation.
18. ACETABULAR COMPONENTS :
The articulating surface of all acetabular components is
made of UHMWPE. Most systems feature a metal shell
with an outside diameter of 40 to 75 mm which is mated
to a polythene liner..
The normal acetabulum is inclined from the transverse
plane at an angle of about 55 degrees. This is somewhat
more vertical than the optimum position for the
prosthetic socket which should be inclined 45 degrees
or less to maximize stability of the joint.
Types :
Cemented acetabular components.
Cementless acetabular components.
Custom made acetabular components.
19. CEMENTED ACETABULAR COMPONENTS
Original sockets for cemented use were thick walled
polyethylene cusp. Vertical and horizontal grooves often
were added to external surface to increase stability
within the cement mantle and wire markers were
embedded in plastic to allow better assessment of
position on postoperative roentgenograms.
More recent designs have a textured metal back
which improves adhesion at the prosthesis cemented
interface. A flange at the rim improves pressurization of
the cement.
They are commonly used in elderly patients, tumour
reconstruction and the circumstances with less chances
of bony ingrowth as in revision THR.
20. CEMENT LESS ACETABULAR COMPONENTS :
Most cementless acetabular components are porous
coated over entire surface for bone in growth with
different methods of initial stabilization. Viz:
transacetabulum screws, pegs and spikes.
Most systems have outer diameter of metal shell of 40-
75 mm with polythene inner liner.
The thickness of the metal backing must be sufficient
to avoid fatigue failure and also good amount of
polythene liner thickness (> 5mm) should be there.
- Custom made acetabular cups
21. BONE CEMENT :
Also known as PMMA (poly methyl methacrylate)
acrylic cement, is not a glue, it has no adhesive
qualities, it is a space filing, load transferring material
In palcos cement the powder is added to liquid for
mixing, in simplex cement the liquid is added to the
powder.
Regular PMMA cement is supplied as 2 sterile
components, a packet of powder containing particles of
PMMA and about 10% opaque barium sulphate and a
polymerization initiator, the other component is a vial
containing methyl methacrylate monomer and a
activator that promote the curing process.
22. ROENTEGENOGRAPHIC EVALUATION :
AP view of pelvis with both hips with upper third
femur with limbs in 15degrees internal rotation.
Spine, knee x-ray taken
Note the following :
Acetabulum : Bone stock, floor, migration,
protrusio, osteophytes and cup size.
Femur : Medullary cavity (size & shape).
Limb length discrepancy
Neck.
23. TEMPLATING :
Draw two horizontal lines : One joining both ischial tuberosites
and the other joining lesser trochanter. Measure limb length
discrepancy as the difference in lengths of lesser trochanters.
Aetabulum : Place acetabular templates on the film and select a
size that closely matches the contour of patients acetabulum. The
medial surface of the cup is at the teardrop and the inferior limit
is at the level of obturator foramen.
Femur : Select a size that most precisely matches the contour of
proximal canal with 2-3 mm of cement mantle. Select a neck
length so that the difference in the height of femoral and
acetabular center is equal to the limb length discrepancy.
Mark the level of anticipated neck cut and measure its distance
from the lesser trochanter.
24. PREPARATION :
Take an informed consent.
Bath the entire extremity and hip with germicidal
solution twice daily after patients is admitted to the
hospital.
Shave the extremity, perineal area, hemipelvis to at
least 10 cm proximal to the iliac crest and wash with
soap as soon before surgery as possible and cover with
sterile towels.
Prophylactic antibiotics.
OPERATION THEATRE :
Laminar flow room with body exhaust system
25. SURGICAL APPROACHES AND
TECHNIQUES :
Each approach has relative advantages and drawbacks.
Choice of specific approach for THR is largely a matter of
personnel preference.
Posterolateral approach with patient in lateral position
without greater trochanter osteotomy and dislocating the
hip posteriorly is commonly done.
26. EVALUATION BEFORE SURGERY
Evaluate whether pain is sufficient to justify surgery.
Asess patient’s general condition (thorough medical examination
with laboratory test is must)
Investigate for any ongoing infection
Physical examination of spine, both lower limbs, soft tissue
around the hip.
Asess the strength of abductor mechanism
Any fixed flexion deformity assessed.
Limb length
Neurological status
When both the hip and knee are arthritic usually hip should be
operated first because THR alters the knee mechanics.
If bilateral involvement present operate on most painful hip first
and after 3 months operate on the other side.
27. Operation
Removing the Femoral Head
Once the hip joint is
entered, the femoral
head is dislocated
from the acetabulum.
Then the femoral
head is removed by
cutting through the
femoral neck with a
power saw.
28. Reaming the Acetabulum
After the femoral head
is removed, the cartilage
is removed from the
acetabulum using a
power drill and a special
reamer.
The reamer forms the
bone in a hemispherical
shape to exactly fit the
metal shell of the
acetabular component.
29. Inserting the Acetabular Component
A trial component, which is
an exact duplicate of your
hip prosthesis, is used to
ensure that the joint will be
the right size and fit for the
client.
Once the right size and
shape is determined for the
acetabulum, the acetabular
component is inserted into
place.
30. Preparing the Femoral Canal
To begin replacing the
femoral head, special rasps
are used to shape and scrape
out femur to the exact shape
of the metal stem of the
femoral component.
Once again, a trial
component is used to ensure
the correct size and shape.
The surgeon will also test the
movement of the hip joint.
31. Inserting Femoral Stem
Once the size and shape
of the canal exactly fit
the femoral component,
the stem is inserted into
the femoral canal.
32. Attaching the Femoral Head
The metal ball that
replaces the femoral
head is attached to the
femoral stem.
33. The Completed Hip Replacement
• Client now has a new
weight bearing surface to
replace the affected hip.
• Before the incision is
closed, an x-ray is made
to ensure new prosthesis
is in the correct position.
34. Treatment by Kinesiologist
-Early Postoperative Exercises-
Regular exercises to restore your normal hip
motion and strength and a gradual return to
everyday activties.
Exercise 20 to 30 minutes a day divided into 3
sections.
Increase circulation to the legs and feet to prevent
blood clots
Strengthen muscles
Improve hip movement
36. Kinesiologist’s Role (cont)
The patient is released few days after the surgery
A list of Do’s and Don’ts
Hip is sore and weak
Start with light exercises
Ergonomics: Rearrange furniture in the house to
make using crutches easier. Setup a ‘recovery
centre’, a table where u put phone, remote control,
radio, medication and other essential things that
you need. It makes it more accessible.
37. - Do’s and Don’ts -
To avoid hip dislocation:
Using 2-3 pillows between your legs when sleeping
(roll onto your ‘good side’
Not crossing your legs
Use chairs with armrest
Not bending forward past 90 degrees
Using a high-rise toilet seat if necessary
Avoid pronation the legs
To avoid stairs, sleep in the living room
39. Post-Surgery Complications
Thrombophlebitis
the blood in the large veins of the leg forms blood clots
within the veins.
If the blood clots in the veins break apart they can
travel to the lung.
Infection in the joint
Dislocation of the joint
Loosening of the joint
