Ashok Sampagar sir's presentation

2. DEPARTMENT OF ORTHOPAEDICS
J.J.M .MEDICAL COLLEGE, DAVANGERE
SEMINAR
TOTAL HIP
ARTHROPLASTY
MODERATORS: PRESENTED BY:
Dr.RAVINATH
M.S.,(ORTHO) Dr. ASHOK .J. SAMPAGAR.
P.G. In orthopedics
Dr.MALLIKARJUN
REDDY
M.S.,(ORTHO ) DATE: 14-09-2011

3. INTRODUCTION :
• Total hip arthroplasty is an
operative procedure in which
the diseased and destroyed
hip joint is resected and
replaced with a new bearing
surface.
• Patients with arthritis can now
look to THA with the object of
maintaining stability, while
relieving pain, increasing
mobility and correcting
deformity.
• MOST SIGNIFICANT BREAK
THROUGH OF THE 20Th
CENTURY

4. HISTORY AND EVOLUTION OF THR
• In 1912, Sir Robert Jones used Gold Foil as an inter
positional layer, other materials used were muscle,
fascia, skin, oil, rubber, celluloid, pig bladder.
• In 1923, SMITH-PETERSON introduced the concept of
mould arthroplasty
• In 1933, PYREX GLASS was chosen as the material for
the first mould..
• In 1937, Venable and Stuck developed VITTALIUM (an
alloy of Cobalt 65%, Chromium 30%, Molybdnium
5%).

5. • In 1950, JUDET and BROTHERS used acrylic
femoral head prosthesis made of methyl
methacrylate..
• In 1952 AUSTIN MOORE and FRED
THOMPSON independently conceived the idea
of fixing endoprosthesis.
• The 1950, WRIST, RING, Mc. KEE-FARRER and
others designed the metal on metal total hip
arthroplasty but did not prove satisfactory
because friction and metal wear

6. • In 1960, Late Sir John
Charnley has done
pioneer work in all aspect
of THA, including the
concept of low frictional
torque arthroplasty,
surgical alteration of hip
biomechanics, lubrication,
materials, design and
clear air operating room
environment.

7. • Between 1966-1988,Maurice Muller from
Switzerland developed a plastic acetabular cup
with a 32 mm diameter chromium-
cobaltmolybdenum femoral head.
• In 1964,Peter Ring began using metal-to-metal
components without cement,
• concept of modular prosthesis developed during
1970
• cementless prostheses came in to picture by mid
1980

8. ANATOMY OF HIP JOINT
• Head of femur
articulates with the
acetabulum of pelvis to
form hip joint
• This is a ball and socket
variety of synovial joint.
• The range of
movements which
permits is less than that
of shoulder joint, but
the strength and
stability are much
greater.

9. Head of the femur :
• Head of femur forms more
than a half of a sphere, and
is covered with hyaline
cartilage except at the fovea
capitis.
• directed upwards, medially
and slightly forwards
Throughout ROM:
• 40% of femoral head is in
contact with acetabular
articular cartilage.
• 10% of femoral head is in
contact with labrum.

10. Acetabulum
• It is hemispherical
cavity on the lateral
aspect of the
innominate bone and
directed laterally
downwards and
forwards
• Acetabulum is formed
by all the components
of the hipbone- ilium ,
ischium, pubis

11. • Hip joint is unique in having a high degree of both
stability as well as mobility
• The stability or strength depends upon :
– The depth of acetabulum which is increased by
the acetabulur labrum.
– The strength of the ligaments and the surrounding
muscles.
– Length and obliquity of the neck of femur which
increases the range of movement

12. Ligaments :
They are :
• Fibrous capsule
• Iliofemoral ligament or
ligament of bigelow
• Pubo-femoral ligament
• Ischio-femoral ligament
• Ligamentum teres
• Transverse ligament of
acetabulum

13. Neck shaft angle or angle of
inclination
• It is the angle between
the axis of the femoral
neck and the long axis
of the femoral shaft.
• On average, it is 135
degrees in the adults

14. Anteversion or angle of femoral
torsion
• Refers to the degree of
forward projection of
femoral neck from the
coronal plane of the
femoral shaft.
• In an adult, it is about
10-15 degrees

15. APPLIED BIOMECHANICS
• The total hip component must withstand many
years of cyclical loading equal to atleast 3 to 5
times the body weight and at time they may be
subjected to overloads of as much as 10 to 12
times the body weight
• So, the basic knowledge of biomechanics of the
THR and hip is necessary to properly perform the
procedure, to successfully manage the problems
that may arise during and after surgery, to select
the components.

16. • The ratio of the length of the
lever arm of the body weight
to that of the abductor
musculature is about 2.5:1.
• So the force of the abductor
muscles must approximate
2.5 times the body weight to
maintain the pelvis level
when standing on the one
leg.
• The estimated load on the
femoral head in the stance
phase of gait is atleast 3 (5/6
BW on femoral head )times
the body weight.

17. Forces acting on hip
• To describe the forces
acting on the hip joint, the
body weight may be
depicted as a load applied
to a lever arm extending
from the body’s center of
gravity to the center of the
femoral head.
• The abductor musculature,
acting on lever arm
extending from the lateral
aspect of the greater
trochanter to the center of
the femoral head.

18. • Force on hip act in coronal
and saggital direction
• Coronal- tend to deflect
stem medially ,
saggital(esp in flexed hip)-
tend to deflect stem
posteriorly
• Hence Implanted femoral
components must
withstand substantial
torsional forces even in
the early postoperative
period

19. CHARNLEY’S LOW FRICTION
ARTHROPLASTY
Charnley advocated the shortening of the body
weight lever arm by
• Deepening the acetabulum and by using small
head.
Lengthen the abductor lever arm by
• Reattaching the osteotomised greater trochanter
laterally or
• By increasing offset between the head and stem
of the femoral component.

20. Centralisation of head and
lengthening of abductor lever arm
• Whenever abductor
lever arm is increased, it
reduces forces on the
hip joint. This lowers
the friction and
frictional torque and
hence lessens the
chance of wear and
loosening of implants.

21. Valgus and Varus position
• A valgus of the head and neck of the femoral
component relative to the femoral shaft more than 140
degree decrease the movement of bending and
increase proportionally the axial loading of the stem
• A mild degree of valgus is usually desirable, but it does
shorten the abductor lever arm mechanism and also
tend to lengthen the limb,may result in the valgus
strain on the knee.
• varus position of the head and neck segment of the
femoral component must be avoided because it
increases risk of loosening,wearing and stem failure.

22. Stress Transfer to Bone
• A major concern with THR is that adaptive bone
remodeling arising from stress shielding
compromises implant support, produces loosening,
and predisposes to fracture of the femur or the
implant itself.
• Cementless stems generally produce strains in the
bone that are more physiological than the strains
caused by fully cemented stems
• Increasing the modulus of elasticity, the stem
length, and the cross-sectional area of the stem
increases the stress in the stem, but decreases the
stress in the cement and proximal third of the
femur.

23. Stem failure :
• Breaks in the area of maximal tensile stress.
Depends on design of the stem, direction of the
load applied( varus/valgus)
• The area of maximal tensile stress is near or at
point where a line drawn through the center of
the head and neck will intersect one drawn on
the lateral edge of the distal half of the stem.
• Decreased with the advent of newer stem design
with greater cross-sectional dimensions, stronger
metals and improved cement techniques.

24. Head and nec k diameters :
• The neck with the smaller
head tends to impinge on the
edge of the cup during a
shorter arc of motion which
tends to loosen the
components and dislocate the
joint.
• The deep socket and beveled
edges and the greater
diameter of the head in
comparison to the neck are
the features that allow a
greater range of motion.

25. Coefficient of friction and frictional
torque :
• CE of friction is the measure of the resistance
encountered in moving one object over the
other.
• It depends on the material used, the finish of
the surfaces ,temperature and the lubricant.
– CE for normal joint- 0.008 to 0.02.
– CF of metal on metal - 0.8
– CF of metal on HDPE (High density poly
ethylene) - 0.02

26. • A frictional torque force is
produced when the
loaded hip moves through
an arc of motion. It is
product of the frictional
force times the length of
the lever arm i.e., the
distance of given point on
the surface of the head
moves during arc of
motion.

27. • Frictional force depends
on coefficient of
friction, applied load
and also on the surface
area of contact
between the head and
socket.
• FT will increase with
large size head.
• Theoretically it causes
loosening of
components.

28. WEAR :
Wear can be defined as
the loss of material from
the surfaces of the
prosthesis as a result of
motion between those
surfaces. Material is lost in
form of particulate debris.
Types :
Abrasive-THR
Adhesive -THR
Fatigue - TKR

29. The factors that determine wear are :
• CF of the substance and finishing surfaces
• Boundary lubrication
• Applied load
• The sliding distance per each cycle
• The hardness of the material
• The number of cycles of movements
The area of greater wear is in the superior
aspect of the socket where the body weight is
applied to the femoral head.

30. • Wear is difficult to measures accurately, it may
be measured by depth of penetration of the
head with in the cup or the volume of debris
produced or by a change in the weight of the
polyethylene
• Newer methods- digitized x-rays and computer
assisted wear measurements
• higher in younger and more active male patients.
• Wear of more than 4 mm may result in neck
impingement on the edge of the cup and
secondary loosening of the acetabulum.

31. BIOMECHANICAL CONSIDERATIONS IN THR :
• Lengths of the lever arm can are surgically
changed to approach r ratio of 1:1 (which reduces
the hip total load by 30 % ).
• Abductor lever arm can be increased either by
increasing the medial offset of the femoral
component or lateral / distal reattachment of
greater trochanter.
• Joint reaction forces are minimal if hip center is
placed in anatomical position.
• Adjustment of neck length is important as it has
effect on both medial offset and vertical offset.
Neck length typically ranges from 25 to 50 mm.

32. • Femoral components must be produced with a
fixed neck shaft angle typically about 1350.
• Restoration of the neck in coronal plane
Increased anteversion – anterior dislocation
Increased Retroversion – posterior dislocation
• Socket depth and beveled edges and greater
diameter of head in comparison of neck allow
greater range of motion.

33. •Neck diameter should approach that to make
neck stronger especially with small femoral heads.
•Frictional torque of small head will be less
compared to larger head.
•Increasing stem length and cross sectional area
increases the stress in the stem.
•Any loading of proximal medial neck likely to
decrease bony resorption and reduces stresses on
cement.
•Loose fitted stem – increase stresses in proximal
femur.

34. 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.

35. • Arthritis
Rheumatoid
Juvenile rheumatoid (Still disease)
Ankylosing spondylitis
• Degenerative joint disease (osteoarthritis,
hypertrophic)
Primary
Secondary
Slipped capital femoral epiphysis
Congenital dislocation or dysplasia of hip
Coxa plana (Legg-Calvé-Perthes disease)
Paget disease
Traumatic dislocation
Fracture, acetabulum
Hemophilia

36. • Osteonecrosis
Postfracture or dislocation
Idiopathic
Slipped capital femoral epiphysis
Hemoglobinopathies (sickle cell disease)
Renal disease
Cortisone induced
Alcoholism
Caisson disease
Lupus
Gaucher disease
Nonunion, femoral neck and trochanteric fractures with
head involvement
• Pyogenic arthritis or osteomyelitis
Hematogenous
Postoperative

37. • Tuberculosis
• Congenital subluxation or dislocation
• Hip fusion and pseudarthrosis
• Failed reconstruction
Osteotomy
Cup arthroplasty
Femoral head prosthesis
Girdlestone procedure
Total hip replacement
Resurfacing arthroplasty
• Bone tumor involving proximal femur or acetabulum
• Hereditary disorders (e.g., achondroplasia)

38. • Most common reasons for total hip
replacement:
• Osteoarthritis 60 %
• Rheumatoid arthritis 7 %
• Fractures/dislocations 11 %
• Aseptic bone necrosis7 %
• Revision 6 %
• Other 9%

39. 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.

40. Hip Replacement Components
• Acetabular component -
consists of two components
– Cup - usually made of titanium
– Liner - can be plastic, metal or
ceramic
• Femoral components
Head
Neck
stem

41. 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 (vertical offset)
-Medial head stem offset ( horizontal offset)
-Version of the femoral neck (anterior
offset)

42. • Vertical offset- 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.
• Medial offset if inadequate, shortens the
moment arm – limp, increase, bony
impingement and dislocation.
• Excessive medial offset –increase stress
on stem and cement which causes stress
fracture or loosening.
• Version of the femoral neck : important
in achieving stability of the prosthetic
joint. The normal femur has 10-15
degree of anteversion.

43. CLASSIFICATION OF TOTAL HIP FEMORAL
COMPONENTS :
• Cemented :
Charnely,Matche Brown,Muller ,alandruccio ,Aufranc – Turner
,Sarmiento,Harris
• Non cemented –
Press Fit : Judet ,Lord ,Sivash ,
Porous Metal : Harris ,Galante,Hydroxyappatite coated
• Bipolar--Bateman ,Gilibertz ,Talwalkar
• Ceramic –Mittelmeir
• Polyacetate -Bombelli Mathes
• Custom made
• Modular System

44. FEMORAL COMPONENTS USED WITH CEMENT

45. • 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

46. CEMENTLESS STEMS WITH POROUS SURFACES

47. Basic principle
• Based on the principle-bone ingrowth from
the viable host bone into porous metal
surfaces of implant.
• Indications for cementless components
involves
1.primarily active young patients
2.and revisions of failed cemented
components.

48. • Two prerequisites for bone ingrowth
1.immediate implant stability at the time of surgery
2.and intimate contact between the porous surface
and viable host bone
• Implants must be designed to fit the endosteal
cavity of the proximal femur as closely as
possible.
• In general, the selection of implant type and size,
as well as the surgical technique and
instrumentation, must all be more precise than
with their cemented counterparts

49. Current porous stem designs
• 1.titanium alloy with a porous surface of
commercially pure titanium fiber-mesh or beads
• and (2) cobalt-chromium alloy with a sintered
beaded surface.
• 2 shapes- Cementless total hip stems are of two
basic shapes: straight and anatomical
• The aim of both types is to provide optimal fit
both proximally and distally and thereby achieve
axial and rotational stability by virtue of their
shape

50. Types of porous coated stems
• Circumferential porous coating-first
generation femoral stems
• Extensive coated stems
• Proximally coated stem – twice the incidence
of thigh pain(stem tip abutment on the
anterior cortex of femur)
• Tapered femoral stems
• Stems with hydroxyapetite coatings

51. NON POROUS CEMENTLESS FEMORAL COMPONENTS
• nonorous femoral
implants have surface
roughening that provide a
macrointerlock with bone
• No capacity for bone
ingrowth but provides
lasting implant stability
• With the concerns about
fatigue strength, ion
release and adverse
femoral remodeling, these
non porous stems came
into use over porous
stems

53. Advantages of cementless femoral stem
prosthesis
• No cement required and problem related to
cement to bone and cement implant interface
reduced
• In young active patients
• Decreased incidence of asceptic loosening
• Less bone destruction
• Circumferential porous coating of proximal stem
provide effective barrier to ingress debris particle
and thus limit early development of osteolysis of
distal stem

54. 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.
• optimum position for the prosthetic socket which
should be inclined 45⁰ or less to maximize
stability of the joint.(normal 55⁰)
Types :
• Cemented acetabular components.
• Cementless acetabular components.
• Custom made acetabular components

55. CEMENTED ACETABULAR COMPONENTS
• Original sockets- thick walled polyethylene cups.
Vertical and horizontal grooves on external surface to
increase stability within the cement mantle
• 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.
• used in elderly patients, tumour reconstruction and
the circumstances with less chances of bony ingrowth
as in revision THR.

56. Cementless Acetabular Components
• Most cementless
acetabular components
are porous coated over
their entire
circumference for bone
ingrowth
• Fixation of the porous
shell with
transacetabular screws

57. • Pegs and spikes driven
into prepared recesses
in the bone provide
some rotational stability
but less than that
obtained with screws.

58. • ZTT socket
Hemispherical , porous
coated cup designed
with dome screw holes
and transacetabular
screws for stability. Six
peripheral screw holes
provide choice of screw
locations for additional
stability and also lock in
the polyethylene insert.

59. Two techniques involved
1.Initial stability of the metal shell against the
acetabular bone using screws, spikes , lugs, or fins
2. Stratch fit- underream the acetabular bone bed
by 1-2 mm and use the roughness of the outer
surface of metal shell to achieve scratch fit
• Expansion cup method-Cup diameter is reduced
with with a special instrument , cup then
implanted and then allowed to return to initial
diameter.

60. polyethylene liner
• Most modern modular acetabular components are
supplied with a variety of polyethylene liner choices
• The polyethylene liner must be fastened securely to
the metal shell.
• Current mechanisms include plastic flanges and metal
wire rings that lock behind elevations or ridges in the
metal shell, and peripherally placed screws
• in vivo dissociation of polyethylene liners from their
metal backings has been reported micromotion
between the nonarticulating side of the liner and the
interior of the shell may be a source of polyethylene
debris generation, or “backside wear.”

61. Alternative Bearings
• Osteolysis secondary to polyethylene particulate debris
has emerged as the most notable factor endangering the
long-term survivorship of total hip replacements.
• alternative bearings have been advocated to diminish this
problem
• These are-
-highly cross linked polyethylene
-metal-on-metal
-ceramic-on-ceramic
-Ceramic on Polyethylene

62. Highly Cross-Linked Polyethylene
• Higher doses of radiation(gamma or
electron,10mrad) can produce polyethylene
with a more highly cross-linked molecular
structure.
• This material has shown remarkable wear
resistance.
• Only short-term data on the performance of
highly cross-linked polyethylenes are presently
available
• Diadvantage -lower fracture toughness and
tensile strength

63. Metal-on-Metal Bearings
• Metal-on-metal implants seem to be tolerant of
high impact loading, and mechanical failure has
not been reported.
• wear rates less than 10 mm/y for modern metal-
on-metal articulations
• But there remains major concern regarding the
production of cobalt and chromium metallic
debris, and its elimination from the body.
• metal-on-metal (MOM) bearings have a ‘suction-
fit’ less chance of dislocation
(J Bone Joint Surg [Br] 2003;85-B:650-4)

64. Ceramic-on-Ceramic Bearings
• Alumina ceramic has many properties that make it
desirable as a bearing surface in hip arthroplasty
• high density- surface finish smoother than metal
implants
• The hydrophilic nature- ceramic promotes lubrication
• Ceramic is harder than metal and more resistant to
scratching from third-body wear particles.
• The linear wear rate of alumina-on-alumina has been
shown to be 4000 times less than cobalt-chrome alloy–
on–polyethylene.
• Ceramic-on-ceramic arthroplasties may be more
sensitive to implant malposition than other bearings. (J
Bone Joint Surg [Br] 2003;85-B:650-4

65. EVALATION BEFORE SURGERY
• Evaluate whether pain is sufficient to justify surgery.
• Assess 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.
• Assess the strength of abductor mechanism
• Any fixed flexion deformity assessed.
• Limb length
• Neurological status

66. • 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.

67. ROENTEGENOGRAPHIC EVAL U ATION
• 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.

68. Templating
• Draw horizontal lines:
one joining both IT and
other joining both
lesser trochanters.
Measure the limb
length discrepancy as
the difference in the
length of lesser
trochanter .

69. • Acetabulum :place
acetabular template on
the film and select a
size that closely
matches the contour of
the pts acetabulam
• Medial surface of the
cup is at tear drop and
inferior limit is at the
level of obturator
foramen

70. • Femur : select a size
that most precisely
matches the contour of
proximal canal with 2-
3mm of cement
mantle.select a neck
length so that the diff in
the height of femoral
and acetabular centre is
equal to LLD

71. • Mark the level of
anticipated neck cut
and measure its
distance from lesser
trochanter. template
the femur similarly in
lateral view

72. 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.

73. PROPHYLACTIC ANTIBIOTICS
• In the operating room 15 to 30 minutes before
the skin incision
• Profound blood loss, an additional operative
dose after 4 hours appears justifiable
• 1st generation cephalosporine- cefazolin
IRRIGATING THE WOUND
Irrigating the wound with a physiological
solution during surgery
– keeps the tissues moist,
– removes debris and blood clots,
– dilutes the number of bacteria that may be
present.

74. OPERATION THEATRE :
• Asepsis in the operating room is crucial
• Body exhaust systems
• Laminar flow rooms
– vertical laminar flow rooms
– horizontal flow systems (easier to install in an operating room with a
low ceiling )
• High efficiency particulate air (HEPA) filters in laminar flow
rooms removing particles 0.3 μm or larger in diameter
• Water-repellent gowns and drapes are recommended.
• Double gloves also are recommended because much
instrumentation is necessary in total hip arthroplasty, and
glove puncture is common.
• Limiting traffic through the operating room

75. 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.

76. POSTOPERATIVE MANAGEMENT
• Hip is positioned in approximately 15 degree
abduction and neutral rotation, with the help of a
triangular pillow splint.
• Light skin traction may be applied for 24 hours. .
• Gentle isometric exercise for few minutes each
hour when they are awake from first operative
day.
• One the second postoperative day patient may sit
on side of the bed avoiding excessive flexion at
hip.
• Drains removed 24-48 hours.

77. • Gait training begun on 2nd
postoperative day, non
weight bearing with a walker,
if cemented-early weight
bearing to tolerance is
permitted
• If cementless-touchdown
weight bearing for 6-8 weeks.
• Patient can be discharged
when patient can walk on
even surfaces, get out of bed,
climb few steps.
• Follow-up at 6 weeks.
Roentgenograms are taken,
full weight bearing advised

78. COMPLICATIONS :
•Inherent to any major surgical
procedure in elderly patients.
•Specifically related to the procedure of
THR:
EARLY LATE
Nerve injury -Loosening
Hemarthrosis/vascular injury -Component failure
Thromboembolism -Osteolysis
Bladder injuries -Heterotrophic
ossification
INDEPENDENT OF TIME
Infection
Dislocation
Trochanteric non union
Femoral fracture
Limbs length discrepancy

79. 1. Nerve injuries (0.7 –3.5%)
• Sciatic, femoral and peroneal nerves may be
injured by direct surgical trauma, traction,
pressure from retractors, limb lengthening (>
4cm) or thermal or pressure injury from cement,
post operative dislocation.
• It is common in revision THR.
• Prevention : By taking due care during surgical
procedures and postoperative period.
• Management : usually recovery occurs within 6
weeks, if not explore the nerve.

80. 2 . Vascular injury : 0.2 % to 3 %
• common during revision surgeries.
• Femoral, obturator, iliac vessels are at risk.
Prevented by
• Careful placement of retractors.
• Due care during transacetabular screw
fixation.
Management :
• Cautery.
• Temporary clamping of iliac vessels
• Trans catheter embolisation preceded by
arteriography
• Alert the abdominal and vascular surgeons

81. 3 . Bladder injuries and urinary tract
complications :
• Urinary tract infection is the most common
complication (7-14 % ), managed with
antibiotics.
• Rarely bladder injury can occur by intra pelvic
escape of cement.
• Bladder injuries are jointly managed with
urologist

82. 4 . Thromboembolism
• Most common serious complication following
total hip arthroplasty
• It is the most common cause of death occurring
within 3 months of surgery and is responsible for
more than 50 % of post operative mortality.
• In western patients without prophylaxis, the
incidence is 40-70 % and fatal pulmonary
embolism is noted in 2 % patients.
• Most common site is deep veins of calf of
operated limb.
Diagnosed by duplex doppler ultrasound and
pulmonary scan.

83. Prevention by :
• Early mobilization
• Active exercises while in bed
• External sequential pneumatic compression boots
and elastic stockings.
Pharmacologic prophylaxis :
• Aspirin
• Low does heparin, adjusted dose heparin
• Dextran
• Warfarin
Early detection and confirmation and
appropriate management with therauptic
anticoagulants like thrombolytic enzymes, warfarin

84. 5 . Infection :
• INCIDENCE
– Charnley (1969 )  8. 9 %
– Fitzgerald (1995)  0 – 11 %
– CURRENT RATE  0.1 to 1 %
(Fortunately)

85. Risk factors
Patient related
• Skin ulcerations / necrosis
• Rheumatoid Arthritis
• Previous hip/knee operation
• Recurrent UTI
• Oral corticosteroids
• Chronic renal insufficiency
• Diabetes
• Neoplasm requiring chemotherapy
• Tooth extraction

86. INSTITUITION RELATED RISK FACTORS:
• Reduce hospital stay(pre-op and post-op)
• Prior pre op assessment as OP
• Clean theatre setup
• Closed door procedure
• Laminar air flow
• Body exhaust system
• U V light

87. PROCEDURE PRECAUTIONS
• Take / give bath in the morning
• Skin preparation
Shaving just before in the side room
• Providone iodine cleaning before and after shave
• Pre op antibiotics
( 1.5 gm Cefuroxime Sodium)
30 – 45 MINUTES BEFORE SURGERY
• Use incise drape ALWAYS
• Use double gloves ALWAYS
• Handle tissues with least trauma
• Wound irrigation, Good hemostasis

88. Fit z geralds classification of infection in THR :
Acute post operative - within 3 months
Delayed –3 to 24 months
Late (Haematogenous) – after 2 years
Stage 1
• Acute post operative period
• Classic fulminant wound infection
• Infected deep hematoma
• Superficial infection that subsequently extend to deep infection
Stage 2
• Deep delayed infection
• Indolent and become manifest from 6-24 months after surgery
Stage 3
• Late infection occur 2 year or longer after surgery in a previously
asymptamatic patient.

89. THA
Clinical Sepsis
Acute/Hematogenous
< 4 wks > 4 wks
Debridement 2-Stage Replantation
Antibiotics (6 wks)
No Success Success No Success
Success
Resection
2-stage Replantation- Arthroplasty

90. 2-stage Reimplantation-
1st stage-
through debridement and reimplantation
with antibiotic coated cement
2nd stage
definitive reimplantation 3 months later

91. 6 . Fractures :
• Fractures of femur, acetabulum, or pubic ramus
may occur during and after THR.
• Femoral fractures are by far the most common.
Management :
• Conservative with traction
• Additional plate and screws
• Plate fixation
• Revision arthroplasty with long stem
• Custom made prosthesis.

92. 7. Dislocation or subluxation :
• Can occur in 3 %
Causes :
• Excess retroversion or
ateversion
• Small size head,
• Laxity of the soft tissue
around the joint.
• Insufficient offset.
Treatment :
Reduction by : Bigelows or
Stimsons method

93. 8 . Heterotopic ossification :
• Most commonly develops
in male patients who have
been operated for
anklyosing spondylitis
• Cause is unknown
• Loss of motion is the
predominant functional
limitation
Management :
• Prophylaxis: Diphosphates
• Low dose NSAIDs,
indomethacin 75mg/day x
6 weeks
• Radiotherapy

94. 9. Loosening :
• Femoral and acetabular loosening are the most serious
femoral and acetabular long-term complications.
• Most common indications for revision arthroplasty.
Cemented femoral loosening :
• Loosening of a femoral stem as defined as radiographically
demonstrable change in the mechanical integrity of the
load carrying cemented femoral component.
• Loosening is present if a radiolucent zone more than 2 mm
wide is seen. Especially if noted about the entire cement
mass and if it is increased progressively in width.

95. Cementless femoral stem :
• Fixation by bone ingrowth is defined as an implant
with minimal or no opaque line formation around
the stem.
• An implant is considered to have a stable fibrous
ingrowth when no progressive migration occurs
but an extensive radio-opaque line forms around
the stem. These lines surround the stem in parallel
fashion and are separated from the stem by a
radiolucent space upto 1 mm wide.
• An unstable implant is defined as one with
definitive evidence of either progressive migration
within the canal and is atleast partially surrounded
by divergent radio-opaque lines that are more
widely separated from the stem at its extremities.

96. Acetabular loosening :
• In general it is agreed that the acetabular cup is
loose if a radiolucency of 2 mm or more in
width is present in all three zones.
• “The diagnosis of loosening is accepted in most
instances if the radiolucent zone about one or
both components is 2mm or more in width and
the patient has symptoms on weight bearing
and motion that are relieved by rest”.
• Solution is the revision THR

97. Resurfacing Arthroplasty
• Surface hip replacement consists of
resurfacing the acetabulum with a thin layer
of bearing surface, and replacement of only
the femoral head (not neck) with a metal ball.
• The ideal candidate for a resurfacing hip
arthroplasty is a young (<60 years old), active
individual, with normal proximal femoral
anatomy and bone density who might be
anticipated to outlive a conventional hip
arthroplasty.

98. • Contraindications include
- proximal femoral osteoporosis,
-large cysts in the femoral head ( >1 cm),
-large areas of osteonecrosis ( > 50 % head
involvement),
-severe acetabular dysplasia,
-marked abnormality of proximal femoral
geometry,
-women of childbearing age,
-known metal hypersensitivity,
-and impaired renal function.

99. • The procedure is more technically demanding
than conventional hip arthroplasty, particularly
with reference to exposure of the acetabulum
because the femoral head is not resected.
• Although the procedure is conservative of bone,
a more extensile soft-tissue dissection is required
for adequate exposure. Resurfacing of the
femoral head alone as a hemiarthroplasty may
be valuable in young patients with osteonecrosis.

100. Minimally Invasive THR
• There are two types of minimally invasive
THA: the single-incision technique and the
two-incision technique.
• Almost all THA done in this manner are press-
fit using porous-coated femoral and
acetabular components because of difficulty
cementing through a small incision.
• The single-incision technique can be
performed as a limited anterior approach as
described by Hardinge,

101. • The two-incision technique employs an incision 1
cm greater than the femoral head diameter,
based over the femoral neck anteriorly.
• Through this, the hip is dislocated anteriorly and
a femoral neck osteotomy performed. Acetabular
preparation is performed with the aid of an
image intensifier, which is also used to ensure
correct positioning of a press-fit acetabular cup.
• A separate 4 cm incision is made over the tip of
the greater trochanter, and femoral canal
preparation and stem insertion are again aided by
an image intensifier.

102. HYBRID HIP REPLACEMENT
• The combination of an uncemented socket and a
cemented stem is commonly called hybrid hip
replacement.
• The goal of this combination of implants is to take
advantage of the clinical reliability, durability, and
ease of use of uncemented sockets and
cemented femurs.
• The method has produced excellent midterm
results and is presently popular in North America

103. • REFERENCES :
• Campbell’s Operative Orthopaedics – Vol.I
• Orthopaedics principles and their Application –
Turek
• Replacement arthroplasty of hip by Harkess.J.W
• Fracture in adults-Rockwood and Green.
• www.hip replacement. org
• Netter’s text book of anatomy.
• Internet-JBJS,JOT