unipolar and bipolar indications approach and procedure

1. HEMIARTHROPLASTY UNIPOLAR
AND BIPOLAR INDICATIONS
APPROACH AND PROCEDURE
Moderator :Prof.Dr A .E Manoharan
D.Ortho,M.S Ortho.
Presentor :Dr.Thouseef A Majeed
M S Ortho PG
VMKVMCH Salem

2. Hemiarthroplasty
• Half joint replacement
• Hemiarthroplasty involves replacing the
femoral head with a prosthesis, while retaining
the natural acetabulum (endoprosthesis)

3. • Fractures of the neck of femur is the commonest
fracture in old aged individuals because of severe
osteoporosis and advancing age causing more
brittleness of the bone
• Non union and avascular necrosis are the two
principal complications of this fracture

4. • Almost 45yrs ago prosthetic replacement was
introduced for solving the unsolved problems of
fracture Neck Of Femur
• Vitallium intramedullary prosthesis had definite role
in its treatment.

5. History
• 1932: Hey Grooves replaced a femoral head with
Ivory
• 1938: Smith Peterson first used Vitallium mould
arthroplasty in the hip in case of ankylosis as a
result of Rheumatoid Arthritis

6. • 1944: Judet brothers introduced Acrylic femoral
head for the treatment of Osteoarthritis.
• 1948: Mc Bride introduced Threaded stem.
• 1950: Moore introduced a self locking Cobalt
chrome alloy prosthesis

7. • 1952 : Thompson worked on a prosthesis at the
same time as Moore
• In 1947: The Bipolar prosthesis first introduced by
James E.Bateman and Gilberty
• 1983 : Charnley-Hastings used Bipolar prosthesis

8. • Prosthesis should not be used for fresh
fractures in preferance to internal
fixation unless there are definite
indications

9. TYPES OF PROSTHESIS
• Two types of prosthesis
–STEM PROSTHESIS
–MEDULLARY PROSTHESIS

10. STEM PROSTHESIS
• It has a head and a stem
• Stem is inserted into the neck and
anchored in the cortex of the shaft
• They are no more used
• E.g– JUDET brothers,
R.E.M.THOMSON

11. MEDULLARY PROSTHESIS
• It has a head and a stem
• Anchored in medullary canal
• It is either fixed by press fit (inference fit) or
by bone cement
• Austin Moore 1957 devised intramedullary
self locking prosthesisfenestrstion to facilitate
bone growth and to increase blood supply

12. DIFFERENT PARTS OF UNIPOLAR
PROSTHESIS
• HEAD: (37mm to 59mm)
• NECK
• STEM: triangular in shape thin and
becomes easy for insertion but chances of
breakage of the tip
• COLLAR
• Fenestrations

13. • Collar is transverse in Moores & in
Thompsons is acutely angled and wide
• FENESTRATION
– Moores prosthesis is fenestrated
– Bone grows through the fenestrations
&
– Anchor the prosthesis inside the shaft

14. AUSTIN MOORE PROSTHESIS
• INDICATIONS
– Failure of closed reduction of a
displaced intracapsular fracture in an
elderly patient >60yrs
– Patient with rhematoid disease with
minimal arthritis of hip

15. – Neglected fractures (>1wk) and when there is no acetabular
damage
– Fracture associated with pagets disease when there is
minimal acetabular damage
• Fractures secondary to malignancy
• Acute displaced intracapsular Fracture

16. • RELATIVE INDICATIONS:
• Advanced physiological age
• Femoral neck fracture that loose fixation several
weeks after operation
• Old undiagnosed fractures of femoral neck (3wks)
• Pre existing diseases of hip

17. • CONTRA INDICATIONS
• Pre existing sepsis
• Active young patient
• Pre existing disese of acetabular cartilage-
o Rheumatoid Arthritis
o Osteoarthritis

18. PREQUESITIES
• Traction internal rotation view should be taken
• Presence of neck with Calcar femorale

19. ADVANTAGES
• Allows immediate weight bearing to return the
patients to pre-fracture level of activity.
• It eliminates Avascular Necrosis and non union.
• Hospital stay is cut short by about 30%

20. DISADVANTAGES
• Salvage procedures are complicated when there is sepsis or
mechanical failure
• At least 2/3rd of patients treated by internal fixation have
functional hips that last the remainder of lifetime, a fact
ignored by prosthetic replacement
• More extensive surgery

21. THOMPSONS PROSTHESIS
• Designed for non union of fracture
neck of femur when there is no neck
available
• Designed to rest on the
intertrochanteric line

22. INDICATION
• Absence of neck
• Non union fracture neck of
femur
• Malignancies
• Bony Secondaries- Pathological
fracture
• Osteoporotic fracture with neck

23. • Although designed for use without bone cement.
• Now frequently used with bone cement due to
o Small stem
o Difficult to achieve stability within femur

24. SELECTION
• Not simple because of radiological
magnifications in preoperative assessment
• Overgrowth of articular cartilage adopts the
acetabulam to the size of metal head

25. FEMORAL HEAD
• Always select the size of femoral head which is removed
• If correct size not available, 1 size smaller size is
preferred to bigger size
• If too large head , equatorial contact occurs, resulting
in a tight joint with a decreased motion and pain.

26. • If head is too small, polar contact occurs with
increased stress over reduced area; leads to erosion,
superomedial prosthetic migration & pain.

27. FEMORAL NECK LENGTH
• If the neck is left excessively long, reduction may
be difficult and pressure on acetabular cartilage is
increased.
• Prostheses should be inserted so that the distance
between the greater trochanter and center of the
femoral head is restored.

28. • Alternatively, attempt to restore the distance
between the lesser trochanter and the acetabulum.
• This will restore the length of the abductor
mechanism and thereby help to prevent
postoperative limp.

29. FIXATION
• Classical fixation is called as Interfernce fit
• Obtained by reaming and driving the prosthesis into the
shaft of the femur

30. POSITION
• Fixed in neutral or slightvalgus,
• Avoid varus, anteversion or retroversion.
• Excessive retroversion causes external
rotational deformity and increased risk of
dislocation with internal rotation.

31. • Excessive anteversion can lead to in-toeing
• 10degree of anteversion is ideal to prevent
dislocations.

32. BIPOLAR PROSTHESIS

33. Gilberty & Bateman in 1974, reported use of
bipolar prosthesis.
 Erosion and protrusion of acetabulum would be
less because motion is present between metal head
& polyethylene socket (inner bearing).
Motion between metallic cup & acetabulum (outer
bearing), since cup is not fixed in bone.

34. • Because of compound bearing surface, bipolar
designs provide greater overall range of motion than
either unipolar designs or conventional THR.
• Made available with a 22 or 32 mm diameter head

35. Recent modifications
Axis of metallic and polyethylene cups are now
eccentric so that with loading of hip.
Metallic cup rotates laterally than medially, and thus
avoids fixation in varus position and avoids
impingement of head on edge of cup.

36. • WIDE RANGE OF MOVEMENTS
• STABILITY WILL BE IMPROVED
• PREVENTS THE COMPLICATIONS
• INCREASED LIFE SPAN OF PROSTHESIS
• CAN DO A TOTAL HIP LATER
ADVANTAGES

37. • WIDE RANGE OF MOVEMENTS
– It is due to size and geometry of inner bearing
– After a certain arc of abduction-adduction movements
and then the further movement occurs between
acetabulam and outer metallic cup of prosthesis

38. • STABILITY WILL BE IMPROVED
– At the degree of movement of the inner
bearing, when the joint tends to dislocate, it is
prevented by movement of outer bearing in
opposite direction.

39. • PREVENTS THE COMPLICATIONS LIKE
– Acetabular erosion and protrusio acetabulii
– Loosening of stem

40. • INCREASED LIFE SPAN OF PROSTHESIS
– As it is a low friction arthroplasty, the wear and tear is
minimal in both implant and the acetabulam
– Hence the life span is more when compared to other
universal endo prosthesis

41. • CAN DO A TOTAL HIP LATER
o Bipolar design affords the advantage of low friction
arthroplasty without implanting a separate acetabular
component.

42. o As absence of fixed acetabular cup eliminates the potential
complications use of methyl methacrylate for fixation of
one acetabular cup, which increases the duration of surgery
and complications associated with fixing the cup with
cement.

43. DISADVANTAGES
• INCREASED INCIDENCE OF DISLOCATION
REQUIRED IN OPEN REDUCTION
• INCREASED COST

44. MODULAR PROSTHESIS
• Implant of choice for displaced
femoral neck of femur
fractures
• In most cases, inserted as a
cemented femoral stem with
neck length, offset, and
acetabular adjustment
• This theoretically decreases
the stress on the acetabular
cartilage

45. • Can be used with a fixed femoral
head (unipolar) or bipolar head and
provides a relatively easy conversion
to a THA, if required in future

46. INSERTION OF PROSTHESIS
• When an uncemented prosthesis used, it is essential to
achieve a firm fit within femoral canal and good seating of
the neck of the prosthesis on the calcar.
• Prosthesis should be tapped into place fairly gently. If
stronger hammer blows used fracture of femur may occur
• Valgus rather than a varus position should be borne in mind

47. • Reduction of prosthesis is achieved by applying
longitudinal traction at the same time gently abducting and
externally rotate the leg.
• Simultaneously pressure is applied to the femoral head so
as to push it distally and medially into the acetabulam.
• Confirmation of the reduction is achieved by assessing that
the hip has full range of movements.

48. Hemiarthroplasty Issues:
Unipolar vs. Bipolar
• Unipolar
– Lower cost
– Simpler
• Bipolar
– Less wear
– More modular
– More expensive
– Can dissociate
– Can convert to total hip
arthroplasty

49. Cement Vs Press fit
• Cement (PMMA)
– Improved mobility, function,
walking aids
– Sudden Intra-op cardiac
death risk slightly increased:
• Non-cemented (Press-fit)
– Pain / Loosening higher
– Intra-op fracture
(theoretical)

50. • Patients with a "stove pipe" type of femur (with no
tapering of medullary canal) are the best candidates
for cemented stems.
• Since there will be a higher risk of fracture with press
fit stems in these patients.
• Risks of cement in hip fractures: methylmethacrylate
embolism (leading to death).

51. Arthroplasty Issues:
Hemiarthroplasty versus THA
• Hemi
–More revisions
• 6-18%
–Smaller operation
• Less blood loss
–More stable
• 2-3% dislocation
• Total Hip
–Fewer revisions
• 4%
–Better functional
outcome
–More dislocations
• 11% early
• 2.5% recurrent
[Cabanela, Orthop 1999]
[JBJS 1994]

52. Approaches

53. POSTERIOR APPROACHES
Gibsons approach(postero lateral approach)
Southern or Mores approach
LATERALAPPROACHES
Anterolateral approach (Watson Jones approach)
Harris lateral approach
McFarland & Osborne lateral approach

54. Posterior approach(Southern Mores
approach
POSITION
• Lateral decubitus with an axillary roll
• All bony prominences are padded

55. LANDMARK: Greater trochanter
INCISION:10-15cm curved centered on
posterior aspect of Greater
trochanter
• Begin proximally 6-8cms
posterosuperior to posterior aspect
of Greater trochanter

56. • Continue to Greater trochanter
• Curve the incision in line with fibers of Greater
trochanter
• Continue along shaft of femur
INTERNERVOUS PLANE: No true plane

57. SUPERFICIAL DISSECTION:
Incise the fascia lata to
expose the Vastus lateralis.
Superiorly split the fibers
of GM(very important)
gently.

58. Gluteus Maximus split in line with its
fibres
Gluteus medius released from crest of
trochanter →short rotators exposed
DEEP DISSECTION:

59. Internally rotate the lower extremity at
the hip to aid exposure of external rotator
tendons
Posterior joint Capsule incised
to expose head & neck

60. DANGERS
• NERVES
 SCIATIC NERVE – from direct injury or retraction or duing
repair of external rotators and capsule when closing
FEMORAL NERVE – from retraction and displacement of
proximal femur during reaming of the acetabulum or
retractor placement
OBTURATOR NERVE. – Retractors

61. VESSELS
INFERIOR GLUTEAL ARTERY – direct injury or
retraction
MEDIAL FEMORAL CIRCUMFLEX – during takedown
of external rotators from bone of posterior proximal femur
OBTURATOR ARTERY – retractor in inferior aspect of
acetabulum.

62. Closure is extremly important with
posterior exposure to lessen
possibility of dislocation
Short rotators are retrieved and are
then reattached through bone holes
in the posterior margin of
trochanter in the region of anatomic
attachment

63. Gibsons approach (1953)
POSITION
• Place the patient in lateral position
INCISION:
• The proximal limb of incision is begin
at a point 6-8 cm anterior to posterior
superior iliac spine & just distal to iliac
crest overlying the anterior border of
gluteus maximus muscle.

64. • It is extended distally to
anterior border of greater
trochanter & further
distally in line of femur for
15-18 cm.
SUPERFICIAL DISSECTION
• Iliotibial tract is incised in
line with direction of its
fibres.

65. • Next, gluteus minimus
and medius are divided at
their insertion to expose
the capsule.

66. ANTEROIOR -LATERALAPPROACH(Watson Jones
approach)
POSITION
• SUPINE – CLOSE TO EDGE – BUTTOCK HANGS
OVER – TILTING THE TABLE TO OPPOSITE SIDE

67. INCISION
FIGUREOF 4 (FLEX AND ADDUCT SO THAT THE LEG LIES
OVER OPPOSITE KNEE) →8-15 cms INCISION CENTERING
ACROSS THE POSTERIOR THIRD OF GREATER TROCHANTER

68. INTERNERVOUS PLANE
NO TRUE INTERNERVOUS PLANE AS BOTH TENSOR FASCIAE
LATAE AND GLUTEUS MEDIUS SUPPLIED BY SUPERIOR
GLUTEAL NERVE

69. Anterior flap consisting of gluteus
medius, minimus & vastus lateralis;
alternatively this can be done by
osteotomy
Anterior Capsule exposed &
capsulotomy performed release
from femoral attachment and a ‘T’
into acetabular rim.
Deep dissection

70. FEMORAL NERVE
o Most laterally placed in femoral triangle.
o Not flexing the hip after dissecting up to anterior rim of acetabulum
o Placing retractors into substance of iliopsoas Or over exuberant
retraction can damage it.
VESSELS –FEMORAL ARTERY & VEIN – damaged by acetabular
retractors that penetrate iliopsoas substance.
DANGERS

71. Harris lateral approach
Position
o Place the patient on unaffected hip,elevate
the affected one to 60 degrees and
maintain this with a sand bag.
Incision
o Make a U’shaped incision ,
o Base at the posterior border of greater
trochanter.

72. • Begin the incision 5cm
proximal to the anterior
superior iliac spine.
• Curve it distally and
posteriorly to the posterio
superior corner of the greater
trochanter

73. • Distally divide the ilio tibial band in line with the skin
incision
• At the greater trochanter , place a finger deep to the band
and feel for gluteus maximus on gluteal tuberosity and
guide the incision on fascia latae posteriorly.

74. • Make a short oblique incision at
the deep surface of the
posteriorly reflected fascia latae
• Begin the incision at the middle
of the greater trochanter extend it
medially and proximally into the
gluteus maximus muscle

75. • Free the abductor muscles
by osteotomizing the
greater trochanter

77. Risks due to trochanteric osteotomy
• Trochanteric non-union
• Trochanteric bursitis
• Heterotopic ossification

78. Position:
o Lateral with affected hip is
above
Incision
o Mid lateral incision centering
greater trochanter.
McFarland & Osborne lateral approach

79. • Gluteal fascia and
iliotibial band are divided
in mid lateral line

80. • Incision is made to bone
obliquely across the
trochanter and distally in
vastus lateralis

81. • Combined mass of
gluteus medius & vastus
lateralis with their
tendinous junction is
elevated & retracted
anteriorly.

82. oTendon of gluteus minimus is split and divided before
retraction proximally
oCapsule opened to expose joint.

83. Preoperative planning

84. Radiographic examination
• X ray of pelvis with both hip AP
view
• Anteroposterior and cross –table
lateral view of the involved proximal
femur.

85. Templating
• Preoperative templating
to determine the
appropriate femoral stem
and unipolar or bipolar
head size.

86. • The normal hip is used as a template to
duplicate normal leg length and hip
offset.
• Proper hip offset helps to maintain proper
soft tissue tension.
• Templating begins anterior posterior view
of pelvis that includes proximal femur.
• Pelvis should not be rotated

87. • 15 degree internal rotation of normal hip eliminates the
normal anteversion.
• The centre of the head is marked in non injured hip.
• A line is drawn down the centre of femoral shaft.
• The distance from this lines to the centre of the femoral
head is the hip offset

88. • Using templates a stem of appropriate size is choosen.
• It is also important to check that stem also matches both
anteroposterior and lateral views of the injured hip before
templating on the normal hip.
• For cemented insertion,adequate space must be maintained
around the stem to accommodate the cement mantel (usually
2mm)

89. • The template is placed over the anterioposterior pelvis film
,dierectly in line with the femoral canal.
• It is then slid down the canal until one of the neck length
markings matches the offset of normal hip.
• The distance from this marking down to the lesser
trochanter is measured using the magnified ruler markings
on the template.

90. • This distance is recorded and later measured
intraoperatively to mark the level of desired neck cut.
• The distance from the lesser trochanter to the centre of the
femoral head is also measured ,to recreate this distance
intraoperatively.

91. • The neck length marking on the template that most
closely matches the offset of the normal is the neck
length that will be used first when performing an
intra-operative trial & assuming intra-operative
stability for the prosthesis itself.

92. • Some patients have hips with larger offset than available on
the templates.
• These patients usally needs a prosthesis of high offset
geometry.
• If high offset stem is not used ,the soft tissue tension of the
hip abducters will be subnormal.
• These muscles may function sub optimally and hip stability
may be compromised.

93. PROCEDURE

94. • Position: according to the approach selected for hemi-
arthroplasty
• Through selected approach hip joint is exposed.
• In osteoarthritis hip is dislocated by flexion adduction and
inernal rotation and neck is ostetomised in posterior
approach
• In lateral approach dislocate the hip anteriorly .

95. • The neck should be osteotomised approximately 1cm
proximal to the lesser trochanter.
• Shortening of the limb by excessive femoral neck resection
and short femoral neck component may lead to prosthetic
dislocation due to soft tissue laxity.
• Lengthening of the limb will result in increased pressure on
the acetabular cartilage and acetabular erosion.

96. • In fracture neck of femur ,head is removed by using cork
screw by incising the ligamentum teres.
• Femoral head size should be measured by using caliper or
template.
–Head in smaller diameter will result in assymetric
load in acetabulum and lead to protrusio acetabuli.
–Head in larger diameter will not fully seat with in
acetabulum and leads to increse risk of prosthetic
dislocation

97. • If pulvinar is excessively large should be trimmed.
• Soft tissues from the posterior and lateral aspect of femoral
neck to the lesser trochanter is excised.

98. • Box osteotome is used to open the femoral canal.
• Sequential reaming done with rasp (reamer) until the
appropriate size (2size smaller to the template) in
appropriate anteversion.

99. Anteversion
• Orientation of the femoral neck in
relation to the femoral condyles at
the level of the knee.
• In most cases, the femoral neck is
oriented anteriorly as compared to
the femoral condyles.

100. • Femoral anteversion averages
between 30-40° at birth,
and between 8-14° in adults
• Males having a slightly less
femoral anteversion than
females

101. • In the case of posterior orientation, the term femoral
retroversion is also applied.
• Excessive anteversion result in internal rotation
deformity and increased risk of anterior hip dislocation.
• Retroversion result in external rotation deformity and
increased risk of posterior hip dislocation.

102. • Trial femoral component neck and head is placed.
• Reduce the hip by traction and external rotation.
• Hip stability is assessed through range of motion.
– External rotation with hip in full extension.
– Flexion and adduction.
– Hip in neutral ,straight pull from the foot

103. • Trial implant replaced with appropriate prosthesis.
• If cementing , the bone plug is inserted and vaccum is
created by suction.
• Cementing is done through retrograde fashion using a
cement gun and good pressurisation technique.(hand
packed)

104. • Prosthesis is inserted using manual force and light taps with
mallet until the fully seated to the level of calcar cut .
• Excess cement is removed.
• Head is reduced.
• Stability is reasessed.
• Short external rotators and underlying capsule are repaired.
• Suturing done by layers.
• Shift the patient in abduction by keeping a pillow between legs.

105. OPERATIVE COMPLICATIONS
• Erosion of acetabulum
• Fracture of stem of prosthesis
• Dislocation of Prosthesis
• Fracture of femur

106. • Retroversion and anteversion of prosthesis
• Varus angulation
• Neck length variation
• Possibility of the sciatic nerve injury

107. POST OPERATIVE MANAGEMENT
• In case of cemented hemiarthroplasty mobilization will be
started on the second day & in uncemented will be after
2weeks
• Use of walker
• Avoidance of stairs and prevention of excessive hip flexion
or adduction
• Avoid squatting & sitting cross legged