shoulder arthroplasty

1. ClASSICAL SHOULDER
ARTHROPLASTY vs reverse shoulder
arthropalsty

2. IN BRIEF
• History.
• Anatomy & Biomechanics.
• Prosthesis deigns.
• Prosthesis & its features.
• Degenerative shoulder & its pathology.
• Types of arthroplasty.
• Surgical approach.
• Complications.
• Advantages & disadvanatages.

3. HISTORY
• The earliest known report of shoulder arthroplasty dates back
to 1893, when a French surgeon, Jules Emil Péan, substituted
a platinum and rubber implant for a glenohumeral joint
destroyed by tuberculosis.
• In the early 1950s, Neer introduced a humeral head prosthesis
for complex shoulder fractures.
• In 1951, he reported his initial results of replacement of the
humeral head with an unconstrained cobalt-chromium alloy
(Vitallium) prosthesis.
• In 1974, the Neer II humeral prosthesis, which was modified
to conform to a glenoid component, was introduced.
• Total shoulder arthroplasty using a constrained articulated
unit in patients with loss of the rotator cuff but with a
functional deltoid muscle was popular in the early 1970s but
had limited success.

5. • In 1893, he attempted the first known total joint
arthroplasty, implanting in the shoulder of a
French waiter in 1893.
• He popularized the hemostat .

7. ANATOMY AND BIOMECHANICS
• The anatomy of the shoulder joint permits more
mobility than any other joint in the body .
• The glenohumeral joint depends on the static and
dynamic stabilizers for movement and stability,
especially the rotator cuff.
• The articular surface of the humeral head is
essentially spherical, with an arc of approximately
160 degrees covered by articular cartilage.
• The glenoid articular surface radius of curvature is 2
to 3 mm larger than that of the humeral head.
• The average neck-shaft angle is 45 degrees .

9. • Normal position of the glenoid surface in relation to
the axis of the scapular body ranged from 2 degrees
of anteversion to 7 degrees of retroversion.
• The superior margin of the humeral head articular
surface normally is superior to the top of the greater
tuberosity by 8 to 10 mm .
• The distance from the lateral base of the coracoid
process to the lateral margin of the greater
tuberosity is called the lateral humeral offset.
• The humeral offset defines the position of the
proximal humeral articular surface relative to the
humeral shaft.

10. • Proximal humeral retroversion is highly
variable, ranging from 0 to 55 degrees.

13. • Increasing the humeral head thickness by 5 mm
has been shown to reduce the range of motion at
the glenohumeral joint by 20 to 30 degrees,
whereas decreasing the thickness by 5 mm can
diminish motion.
Replacement of the
anatomical humeral head size and position aims
to restore normal shoulder biomechanics.

14. PROSTHESIS DESIGN
• Based on the clinical success of the Neer II
implant, numerous modular designs were
developed to improve implant fixation and
durability .
• Modularity allows a better fit for individual
patients because various stem and head sizes can
be “mixed and matched” to an individual’s
anatomy.
• Most stems are made of cobalt-chrome alloy,
have proximal porous ingrowth coating, and have
proximal fins(A fin is a thin component or
appendage attached to a larger body or structure)
for rotational stability.

16. • Center of the humeral head was
2.6 mm posterior and 6.9 mm
medial to the center of the
humeral shaft .
Anatomical positioning of the
humeral head prosthesis is best
done with an eccentric locking
position of the Morse taper, which
allows adjustments to the variable
medial offset and any posterior
offset.
Postoperative kinematics after
total shoulder arthroplasty do not
mimic those of the native shoulder.

17. • Prosthetic head should be within 4 mm of the
original humeral head thickness.
• Most stems can be inserted with a press-fit or
cemented technique.
• Cemented all-polyethylene components remain
the most frequently used glenoid components,
but most now have an increased radius of
curvature compared with the humeral head (2 to
6 mm larger) to allow translation during
movement and to decrease edge loading .

19. ROCKING HORSE EFFECT
Such translation in a perfectly congruent joint may have a potential for localized wear
and loosening (rocking-horse effect); however, increased loosening and polyethylene
have not been reported to occur when the radii of curvature of the glenoid component
and the humeral head are matched within 2 mm

20. • Noted fewer radiolucencies with mismatches
between the glenoid and humeral head
diameters of more than 5.5 mm (6 to 10 mm ).
• Improved stability with increasing sizes of
glenoid components .
• Bone quality was important in achieving solid
glenoid component fixation .
• Polyethylene glenoid components generally have
a single central or offset keel or multiple pegs for
fixation into the glenoid vault .

21. Bone stresses were not
much affected by
prosthesis design except at
the tip of the central peg
or keel.
They did conclude,
however, that pegged
prostheses were better for
normal bone, whereas
keeled components were
better for bone in
rheumatoid patients.

23. GLENOHUMERAL ARTHRITIS
• Patients typically present with global pain about
the shoulder with difficulty performing overhead
activities.
• Joint space narrowing is not commonly seen in
the shoulder owing to the non–weight-bearing
position of the shoulder.
• Symmetrical joint space narrowing in RA.

25. Shoulder OA shows
subchondral
sclerosis and a large
osteophyte on the
inferior aspect of the
humeral head This
so-called “goat’s
beard” is
pathognomonic of
advanced
glenohumeral
degeneration.

27. CAPSULORRHAPHY ARTHROPATHY
• Capsular distension.
• Posterior glenoid wear.
• Loose bodies.
• Osteophytes .

28. PREOPERATIVE PALNNING
• Routine Blood Investigations.(CBC,ESR,CRP)
• X-rays.
• MRI.
• CT(3D).
• Rule out sp.bacteria.(Aspiration and culture of
glenohumeral joint fluid, holding the culture for
at least 14 days to isolate Propionibacterium
acnes)

29. RADIOGRAPHY
• Anteroposterior views .
• A 40-degree posterior oblique view in neutral
internal and external rotation .
• Supine lateral scapula view (anterior oblique
AP).
• Axillary lateral view.
• Radiographs of the opposite, uninvolved
shoulder.

30. AXILLARY LATERAL VIEW

32. AXILLARY RADIOGHRAPHYPOSTERIOR OBLIQUE VIEW

33. MRI often shows-
• -Thinning of the subscapularis and degenerative
changes in the joint.
-Rotator cuff status.
-Increased capsular volume posteriorly
&capsular contraction anteriorly.
-Precollapse osteonecrosis, MRI is useful for
visualizing the area of dead bone and is often
the best tool to make the diagnosis.

34. PRECOLLAPSE OSTEONECROSIS

35. CT
• Excellent picture of the patient’s glenoid bone
stock and the pattern of glenoid wear.
• Loose bodies may be seen in the axillary or
subscapularis recess.
• Malunions or nonunions, three-dimensional
reconstruction helps to precisely show the bony
deformities and defects before surgery.
• Accurate glenoid component placement with
either conventional or patient-specific implants.
• The role of preoperative planning based on three-
dimensional CT scans to optimize implant
position, size, and range of motion is an evolving
area of investigation.

36. CT SHOWING DEGENERATIVE ARTHRITIS

37. PREOPERATIVE CHECKLIST
• Check for-Rotator cuff tears(Mc in RA than OA).
Biceps tendinitis.
Acromioclavicular joint involvement.
Passive and active shoulder movements.
Palpable crepitus feeling.
Adhesive capsulitis.

38. OBSTACLES TO ARHTOPALSTY
• Malunited proximal humerus #(osteotomy
usually is unnecessary as newer short-stem and
stemless designs allow accommodation of these
deformities).
• Major infective foci.

40. HEMIARTHROPLASTY
INDICATIONS
• The predominant indication is end-stage joint
degeneration in a patient with glenoid
resurfacing.(CI for hemiarthroplasty).
• Osteonecrosis,Glenoid dysplasia.
• Cuff tear arthropathy.(With retained forward
shoulder elevation)
• Young laborers, patients with glenoid bone stock
insufficiency, and patients with high activity levels
may benefit more from hemiarthroplasty.
• Rotator cuff tears remain a contraindication to
prosthetic glenoid(excellent pain relief and moderate improvements in
function and motion after TSA acc. to some)

41. MATSEN INDICATIONS OF
HEMIRTHROPLASTY
(1) The humeral joint surface is rough, but the
cartilaginous surface of the glenoid is intact, and there
is sufficient glenoid arc to stabilize the humeral head;
(2) There is insufficient bone to support a glenoid
component;
(3) There is fixed upward displacement of the humeral
head relative to the glenoid (as in cuff tear
arthropathy or severe rheumatoid arthritis);
(4) There is a history of remote joint infection; and
(5)Heavy demands would be placed on the joint
(anticipated heavy loading from occupation, sport, or
lower extremity paresis).

42. CONTRAINDICATIONS
• Recent sepsis.
• Neuropathic joint.
• A Paralytic disorder of the joint.
• Deficiencies in shoulder cuff and deltoid muscle
function.
• Lack of patient cooperation.

43. HEMIARTHROPLASTY

45. Biceps tenodesis before incising
the subscapularis.

47. POSTOPERATIVE CARE
• Gentle home exercise program with passive forward
elevation to 90 degrees and passive external rotation
to neutral.
• Encouraged to use a pillow behind the elbow while
recumbent in the sling to support the extremity.
Full-time sling immobilization continues for 6
weeks, followed by 6 weeks of sling use only in
unprotected environments.
• Therapy progresses to full passive range of motion
by 6 to 12 weeks and to isometric strengthening at
10 weeks.

48. OUTCOMES
• Hemiarthroplasty has been reported to initially relieve pain in 75% to
95% of patients with glenohumeral arthritis and severe rotator cuff
deficiency, with modest improvements in range of motion and
strength.Results have been compromised by persistent pain from
glenoid arthrosis, anterosuperior instability, and progressive bone
loss.
• The best results of shoulder hemiarthroplasty are in patients with
osteonecrosis, good pain relief in 90%, with an almost normal range of
motion .Results are not quite as good in patients with rheumatoid
arthritis, osteoarthritis, glenoid dysplasia, or posttraumatic
glenohumeral arthrosis.

49. PEARLS
• Good deltoid function and an adequate
coracoacromial arch are key to successful
hemiarthroplasty in patients with severe rotator cuff
arthropathy.
• If it is found to be torn, as much of the rotator cuff
as possible should be repaired, emphasizing anterior
and posterior reconstruction to provide stability to
the implant.

50. Care should be taken
to avoid a “big head” humeral prosthesis that can “overstuff”
the joint

51. “Rocking-horse effect”
• Eccentric loading of the glenoid caused by
superior migration of the humeral component
has been cited as a cause of glenoid loosening.
• Association between glenoid component
loosening and irreparable rotator cuff tears.

52. TOTAL SHOULDER ARTHROPLASTY
• The primary indication for total shoulder
arthroplasty is endstage glenohumeral joint
degeneration with an intact rotator cuff.(OA,RA,
osteonecrosis, posttraumatic arthritis, and
capsulorrhaphy arthropathy)

53. CONTRAINDICATIONS
• Active or recent infection.
• Irreparable rotator cuff tears.
• Paralysis with complete loss of function of the
deltoid.
• Debilitating medical status and uncorrectable
glenohumeral instability.

54. SURGICAL TECHNIQUE
• Approach the glenohumeral joint as described .
• Fukuda retractor on the posterior aspect of the
glenoid and subluxing the humerus
posteriorly.Débride the glenoid vault .
• Typically, there is posterior erosion of the glenoid and
the anterior rim of the glenoid needs to be lowered to
reestablish correct version .This can be done by
eccentric reaming.
• Once the glenoid vault is débrided, make a centering
hole, typically with a guide . If posterior rim wear is
significant and the anterior rim has not been lowered,
the component sits excessively retroverted, and
anterior glenoid neck perforation is likely .

56. • Once reaming is complete, prepare the glenoid for
either the pegged or keeled implant .
• Once the appropriate head is selected, dry the Morse
taper and tap the head into position. Reduce the
glenohumeral joint, and close the wound.
• The durability of total shoulder replacement is as
good as or better than that of hip and knee
replacements. Results at long-term follow-up in
several series have reported 85% component
retention at 20 years of follow-up and revision rates
for all causes averaging less than 10%.

57. Problem of and solution for uneven wear and erosion of glenoid. A, Area of wear. B, If glenoid component is inserted without correction of slope, anchoring device
passes out of medullary canal; tilt and loss of height also make implant unstable. C and D, Severe erosion is corrected by bone grafting. Piece of humeral head is
secured to scapula with 4-mm AO navicular screw. Lesser erosion can be offset by building up low side with acrylic cement or lowering high side. Building up with
cement is not recommended because of feared cement loosening. Lowering high side often requires shortening holding device of glenoid component and creates
laxity between components, which can make implant temporarily unstable and requires special postoperative care. Glenoid component with thick side is available
for moderate uneven erosion.

58. • Although hemiarthroplasty can provide pain relief
and increased range of motion in patients with
osteoarthritis and a concentric glenoid, total
shoulder arthroplasty generally provides superior
results in terms of patient satisfaction, function, and
strength, especially at longer-term follow-up.
• Cochrane Database systemic review of seven studies
found that total shoulder arthroplasty is associated
with better shoulder function than
hemiarthroplasty.

59. In 1987, Grammont et al. [14, 15] introduced
two major innovations in the reverse
prosthesis: notably a large glenoid hemisphere
with no neck and a small almost horizontally
inclined (155 degrees) humeral component
covering less than half of the hemisphere.

60. REVERSE SHOULDER
ARTHROPALSTY
• The primary indication for reverse
total shoulder arthroplasty is a
nonfunctional rotator cuff. Until the
introduction of reverse total shoulder
arthroplasty, patients with cuff tear
arthropathy were generally treated
with hemiarthroplasty.
• Contraindications include loss or
inactivity of the deltoid and excessive
glenoid bone loss that would not allow
secure implantation of the glenoid
component.

61. CUFF TEAR ARTHROPATHY
SOURCIL SIGN
DECREASED JOINT SPACE
PROXIMAL HUMERUS
MIGARATION
PSEUDOHUMERAL
ARTICULATION
OSTEOPHYTES

62. COMPLICATIONS OF SHOULDER
ARTHROPLASTY
• Overall complication is approximately 15%.
• Glenoid loosening is most common.
• Glenohumeral instability,
• Rotator cuff tear,
• Periprosthetic fracture, infection.
• Implant failure including dissociation of
modular prostheses, and
• Deltoid weakness or dysfunction.

63. • Complications after total shoulder arthroplasty tend
to occur late in the postoperative course (5 to 10
years after surgery).
• Component loosening has been reported to occur
approximately 8 years after surgery, infection at 12
years, and periprosthetic fractures at 6 years.
• Reverse total shoulder arthroplasty initially resulted
in relatively high complication rates (50%) and
some unique complications.
• The most common complications after reverse total
shoulder arthroplasty are scapular notching,
hematoma formation, glenoid dissociation such as
baseplate failure or aseptic loosening, glenohumeral
dislocation, acromial and scapular spine fractures,
infection, loosening or dissociation of the humeral
component and nerve injury.

64. INTRAOPERATIVE COMPLICATIONS
• The most common intraoperative complications
in shoulder arthroplasty are fracture, usually of
the humeral shaft in the mid to distal diaphysis
nerve injury, most often to the axillary nerve.

67. POSTOPERATIVE COMPLICATIONS
• Glenoid loosening,
• Glenohumeral instability,
• Rotator cuff tears,
• Periprosthetic fracture,
• Infection,
• Deltoid rupture,
• Tuberosity nonunion or malunion, humeral
loosening, impingement, heterotopic bone
formation, mechanical failure of components,
and loss of motion.

68. GLENOID LOOSENING
• Symptomatic loosening of glenoid or humeral components
is the most common problem encountered in total
shoulder arthroplasty.
• Radiographic lucent lines at the cement-bone interface of
the glenoid component have been observed in varying
degrees in up to 96% of patients.
• Injection of the cement under pressurization provided by a
syringe and application of cement on the back side of the
glenoid component has been reported to improve glenoid
component fixation by providing more complete
cementation.
• Radiolucencies tend to evolve late (after 5 years),
indicating the need for further technical and prosthetic
innovation to improve long-term component durability.
• Radiolucent lines also were significantly associated with
osteolysis.

69. • Keeled or peg glenoid.
• Glenoid lucencies develop over time, most likely
as a result of the stresses placed across the bone-
cement-polyethylene interface.

70. • Instability is the second leading cause of complications
associated with shoulder arthroplasty.
• 80% of instability complications after total shoulder
arthroplasty involve anterior or superior instability
• Anterior instability most commonly is associated with
subscapularis failure, glenoid anteversion, malrotation of
the humeral component, or anterior deltoid dysfunction.
• Progressive superior migration of the humeral head has
been reported in association with dynamic muscle
dysfunction, attenuation of the supraspinatus, failed
rotator cuff repairs, and frank rupture of the rotator cuff.
INSTABILITY

72. PERIPROSTHETIC FRACTURE
• The reported prevalence of postoperative
periprosthetic humeral shaft fractures ranges
from 0.5% to 2%,most frequent in women &
rheumatoid arthritis.

73. ROTATOR CUFF FAILURE
• Rotator cuff failure is the fourth most common
complication after shoulder arthroplasty.
• Factors reported to be associated with postoperative tears
of the subscapularis tendon include multiple operations,
overstuffing of the joint, overly aggressive therapy
involving external rotation and tendon compromise by
lengthening techniques.
• Preoperative fatty infiltration of the infraspinatus and a
glenoid component placed in superior tilt are risk factors
for subsequent rotator cuff failure.
• Repair of large or massive tears may be impossible. One
treatment for this difficult problem involves removing the
glenoid component, bone grafting of the glenoid cavity
defect, and allowing the humeral prosthesis to migrate
superiorly.

74. INFECTION
• Infection is rare after both primary anatomic and
reverse total shoulder arthroplasty
(approximately 2%); male sex and younger age at
the time of arthroplasty are risk factors.
• Propionibacterium acnes is the most commonly
isolated organism after shoulder arthroplasty but
has a protean presentation and is very difficult to
diagnose. The most common symptom is
unexplained pain.
• Intraoperative findings of humeral loosening,
turbid fluid, and membrane formation all
correlate with the likelihood of a positive culture
for P. acnes.

75. • If the infection is identified early (3 to 6 weeks
after surgery) and the organism is gram
positive, retention of the components can be
considered. One-stage irrigation and
debridement with replacement of the humeral
head, along with appropriate parenteral
antibiotic therapy, has been shown to be
effective treatment.
• If the organism is gram negative or the
infection occurs late, removal of the implants
and all cement generally is recommended

76. • Deltoid muscle dysfunction caused by axillary
nerve injury or detachment of the deltoid muscle
can result in a catastrophic loss of shoulder
function.
• Heterotopic ossification has been noted to occur
after shoulder arthroplasty in 10% to 45% of
patients. Male gender and osteoarthritis are risk
factors.

77. • Neer published a large rate of satisfactory results
in his initial study. Most studies published later
have reported a higher rate of failure. In the
absence of complications, most patients
experience little pain, but their motion and
strength varies depending on the quality of the
reconstruction and tuberosity healing. Average
elevation is approximately 90 to 100 degrees,
although it may range less than 30 to more than
150 degrees .

79. • The main biomechanical advantages of reverse prosthesis
according to Grammont’s concept are as follows:
(1) the large ball offers a greater potential arc of motion and
more stability than a small ball,
(2) the small lateral offset (absence of neck) places the center of
rotation directly in contact with the glenoid surface and
reduces the torque at the point of fixation of the glenoid
component,
(3) medializing the center of rotation recruits more of the
deltoid fibers for elevation or abduction, and
(4) lowering the humerus increases tension on the deltoid.
These biomechanical properties may lead to better
functioning of the deltoid by an increase of its lever arm and
moment of action, compensating for the lack of a functional
rotator cuff .

80. • An important limitation of this nonanatomical
prosthesis is its inability to restore active
internal and external rotation. This is caused
mainly by design limitations of the prosthesis
producing mechanical impingement and
malfunctioning of the rotator cuff remnants. It
can also be explained by the slackening of the
remaining external rotators due to the
medialization of the center of rotation.

82. • A second prosthetic limitation of this reversed principle
rises from its hinged rotation (the humeral component
rotates around the glenosphere) instead of a spinning
rotation (the humeral head rotates on the spot) as seen
in an anatomical setting. This type of rotation requires
more room, because without it, a conflict between the
humeral and glenoid parts can occur.
• Best known is the scapular notching in which the
humerus is in conflict with the infraglenoid tubercle
.This mechanical impingement also exists in the
transverse plane of the body, thereby limiting the range
of external and internal rotation and possibly leading to
mechanical prosthetic failure when the tuberosities
bump against the glenoid.

83. • In 2005, these authors reported a minimum
two-year follow-up study of sixty shoulders with
cuff-tear arthropathy [40]. Reverse arthroplasty
was associated with statistically significant
improvements in pain and function, with a mean
active elevation of approximately 105 degrees.
However, there was a 17 % complication rate and
a 12% rate of revision for implant failure.