2. INTRODUCTION
Joint replacement – common, effective procedure for relief of
disability due to severe joint pain and loss of function.
most common joints replaced are the hip, knee and shoulder.
Most patients for jt replacement have generalized degenerative
joint disease (eg.OA).
Other conditions necessitating joint replacement surgery include:
› rheumatoid arthritis
› osteoporosis and fracture
› metastatic lesions and pathological fractures
› avascular necrosis of the femoral head.
Most patients are elderly, with associated problems such as HTN,
IHD, COPD or renal disease.
Younger pts presenting for jt replacement surgery often suffer from
rheumatoid arthritis, severe osteoporosis or obesity.
Presentation for revision of previous replacement is increasingly
common.
3. Preoperative assessment
Problems in multiple systems are common because
most patients are elderly.
There are specific types of pts who are more likely
to have orthopedic surgery and are more likely to
have perioperative complications.
› geriatric pts
› rheumatoid arthritis pts
› ankylosing spondylitis pts
4. Geriatric Patients
Postmenopausal, ageassociated osteoporosis
higher risk of fractures.
Ageassociated osteoporosis may be due to
increased circulating parathyroid hormone &
decreased vitD, growth hormone.
With osteoporosis disproportionate loss of
trabecular (structural) bone – thus at risk for stress
fractures.
Although all bones are at risk, thoracic and lumbar
spine, proximal femur, proximal humerus, wrist are
at highest risk.
5.
6. Osteoarthritis
most common type of arthritis loss of articular
cartilage, inflammation.
Clinical manifestations pain, crepitance, reduced
mobility, and deformity of involved joints.
Hands – spurring, swelling of the distal IP jts
(Heberden's nodes) and PIP jts (Bouchard's nodes).
no systemic manifestations of osteoarthritis should
be aware of previous orthopedic surgeries/ jt
replacements / jts which are painful / limited
mobility.
important for surgical positioning and the choice of
an appropriate anesthetic.
7. Rheumatoid Arthritis
chronic inflammatory form of arthritis, affects about
1% of adults, prevalence 23 times higher in women
than men.
characterized by persistent joint synovial tissue
inflammation leading to bone erosion, destruction
of cartilage, and loss of joint integrity.
RA also a systemic disease, affecting multiple
organ systems.
often progresses through multiple exacerbations &
remissions.
commonly present with pain and stiffness in
multiple joints.
characterized by morning stiffness often lasting >1
hr after initiating activity.
8.
9. usually wrists & MCP jts are involved (distinguishes
RA from OA), boggy, tender & warm.
may have prominent epitrochlear, axillary, &
cervical LN enlargement.
SC rheumatoid nodules may surround joints,
extensor surfaces, and bony prominences.
pts taking NSAIDs should be assessed for GI SEs &
renal complications.
Glucocorticoids highly effective at relieving
symptoms but used at low doses & sparingly ( due
to SEs of osteoporosis, cataracts, cushingoid
symptoms, hyperglycemia).
Pts taking glucocorticoids need stressdose steroids
for their operations.
10. Airway management can be challenging
› TMJ synovitis limits mandibular motion & mouth opening.
› Arthritic damage to cricoarytenoid joints diminished
movement of VCs, narrowed glottic opening; preop as
hoarseness and stridor.
› During DLscopy, VCs may appear erythematous
/edematous, reduced glottic opening may interfere with
passage of ETT.
› increased risk of cricoarytenoid dislocation with traumatic
intubations.
› Arthritis of Cspine (atlantoaxial subluxation Flexion of
head displacement of odontoid process into cervical
spine and medulla compression of vertebral arteries
precipitate quadriparesis, spinal shock, and death).
› Preop cervical flexionextension radiographs required to
plan for awake fiberoptic tracheal intubation, Cspine
should be protected with collar.
12. Ankylosing Spondylitis
chronic inflammatory arthritic disease that results in
fusion of the axial skeleton.
ossification of axial ligaments progressing from
sacral lumbar region cranially, resulting in a
significant loss of spinal mobility
significant challenge to us with regard to airway
reduced movement of their Cspines & TMJs.
In most cases, awake fiberoptic endotracheal
intubation is required for GA.
increased rigidity of the thoracic spine in most
cases also necessitates intraoperative controlled
mechanical ventilation.
13. Although neuraxial anesthesia is better alternative
to GA, ossification of spinal ligaments closes
intervertebral spaces, blocking access to epidural
space.
Extraskeletal manifestations
1. aortic insufficiency
2. cardiac conduction abnormalities
3. Iritis
4. upper lobe fibrobullous disease ,pleural effusions.
Strict attention to positioning to avoid fracture of
the fused spine with concomitant spinal cord
trauma.
14. Assessment of co-morbidities
Cardiopulmonary reserve
estimated by assessment of exercise tolerance.
may be impossible/ inaccurate (limited exercise).
In these circumstances the following may be used:
PFTs, ABG, RA SPO2
resting ECG (silent ischaemia / previous MI)
2DEcho (LV function, WMA and valvular abnormality)
limited relevance information only about function of rested,
rather than stressed, cardiopulmonary systems.
Dobutamine stress tests provide information about cardiac
function under stress but they are not readily available.
15. Renal function
may be impaired owing to age, HTN or chronic use
of NSAIDs.
Musculoskeletal
other joint involvement is common.
range of limb and neck movements should be
noted.
Obesity may be a cause or consequence of
degenerative joint disease.
Assessment for positioning on table and for regional
blockade should be made.
16. Pts Excluded for Single Operation for
Bilateral Total Knee Arthroplasty
Age ≥ 75 yr
ASA class III
Active ischemic heart disease (positive stress test)
Poor ventricular function (LVEF < 40%)
Oxygen-dependent pulmonary disease
Patients considered at increased risk for morbidity and mortality
IDDM
Renal insufficiency
Pulmonary hypertension
Steroid-dependent asthma
Morbid obesity (BMI > 40)
Chronic liver disease
Cerebrovascular disease
17. Preoperative preparation
Preop assessment should be carried out as above.
Optimization of co-morbidities is required.
Cross-matched blood must be available.
DVT prophylaxis is required. If a regional technique is
planned, ensure appropriate timing of low-molecular-
weight heparin.
Antibiotic prophylaxis (usually cephalosporin or
aminoglycoside) is required.
Invasive monitoring is seldom indicated unless there is sig-
nificant cardiac disease or large blood loss is anticipated.
Large bore IV access is required (non-dependent arm for
laterally positioned patients).
18. Thromboprophylaxis in Orthopedic
Surgery
1 of leading causes of morbidity after ortho surgery.
THR, TKR, hip and pelvic fracture surgery - highest
incidence of VTE, including DVT and PE.
Pts with symptomatic PE have 18-fold higher risk of
death than pts with DVT alone.
short-term complications of survivors of acute DVT
and PE - prolonged hospitalization, bleeding
complications related to DVT and PE treatments,
local extension of DVT, and further embolization.
Long-term complications include post-thrombotic
syndrome, pulmonary hypertension, and recurrent
DVT.
19. As venous thrombi consist of fibrin polymers, anticoagulants
administered for the prevention and treatment of DVT.
Thrombolytics should be administered only in event of a
severe, possibly fatal PE.
LMWH is recommended over unfractionated heparin (IV/SC)
for initial therapy of DVT and PE.
LMWHs do not require monitoring of coagulation.
Although DVT prophylaxis may be more efficient when
started preoperatively, the risk of surgical bleeding also
increases.
LMWH should be continued for at least 10 days in routine
orthopedic procedures & in patients not considered high risk.
Extended prophylaxis to 28 to 35 days would be supported in
patients with evidence of a DVT or at higher risk for DVT.
20. Risk factors for development of PE after surgery
1. advanced age
2. Obesity
3. previous PE and DVT
4. Cancer
5. prolonged bed rest
Warfarin - long-term treatment of DVT, with a target
INR of 2.5 maintained for the duration of therapy.
alternative to LMWH is fondaparinux, synthetic
pentasaccharide (selective inhibitor of factor Xa),
prolonged half-life of 18 hours.
When administered OD, fondaparinux produces
predictable anticoagulant response.
21. use of periop anticoagulants has significant impact on use of
RA, esp. neuraxial anesthesia (risk of an epidural hematoma).
ASRA - updated consensus conference recommendations
with regard to the use of anticoagulants and RA.
risk of epidural hematoma is significantly increased with use
of LMWH, so following recommendations have been made:
1. An interval of 12 hrs after administration of usual dose of
LMWH and placement of a neuraxial block.
2. In patients receiving larger doses of LMWH (enoxaparin
1 mg/kg every 12 hrs), delay should be extended to 24 hours.
3. Epidural catheter removal at least 8-12 hrs after last LMWH
administration, or 1 to 2 hrs before the next.
22. Intraoperative Management
THR
APPROACHES
anterior / lateral approach.
anterior approach - advantage of exposure without
violation of the muscles, but restricts full access to the
femur with the risk of lateral femoral cutaneous nerve
injury.
lateral posterior approach - excellent exposure to the
femur and the acetabulum with minimal muscle
damage, but increases the risk of posterior dislocation.
Most surgeons prefer lateral posterior approach,
placing the patient in lateral decubitus position, surgical
side up, for operation.
23.
24. POSITIONING
anesthesiologist must be aware that this position may
compromise oxygenation, esp in obese and severely arthritic
pts, owing to V/Q mismatch.
to prevent excessive pressure on the axillary artery and
brachial plexus by the dependent shoulder, an anterior roll or
pad must be placed beneath the upper thorax.
TECHNIQUE
nerve supply to hip joint includes obturator, inferior gluteal,
and superior gluteal nerves - RA best achieved with SAB/
epidural anesthetic.
lumbar paravertebral block may be used for postop
analgesia when postop anticoagulation requires removal of
epidural catheter.
25.
26. BLOOD LOSS
can be significant.
Several studies have shown controlled hypotensive epidural
anesthesia with MAP of 60 mm Hg can reduce intraop blood
loss for primary THRs to approx 200 mL.
Elderly patients able to tolerate this degree of blood pressure
reduction without cognitive, cardiac, or renal complications.
hypotensive anesthesia may improve the cement prosthesis
to bone fixation by limiting bleeding in the femoral canal.
femoral prosthesis can be fixed to femoral canal through
methyl methacrylate cement or bony ingrowth.
Cemented fixation of the femoral prosthesis has been
complicated by “bone-cement implantation syndrome,”
which may result in intraop hypotension, hypoxia, and
cardiac arrest and FES postoperatively
27. Several mechanisms suggested –
embolization to circulation of bone marrow debris during
pressurization of femoral canal
toxic effects of circulating methyl methacrylate monomer
release of cytokines during reaming of femoral canal
promoting microthrombus formation and pulmonary
vasoconstriction.
hypotension should be treated with epinephrine.
Risk factors for this complication include revision surgery, a
long-stem femoral prosthesis, THR for a pathologic fracture,
preexisting pulmonary hypertension, and the quantity of
cement used.
28. TKR
TECHNIQUE
innervation of the knee includes tibial nerve, common
peroneal nerve, posterior branch of obturator nerve, &
femoral nerve.
RA as SAB / CSE / combination of femoral & sciatic block can
be provided for the surgery.
Single-injection femoral nerve blocks in combination with
intravenous and epidural patient-controlled analgesia have
been employed to manage postoperative pain and improve
functional recovery.
When LMWH has been instituted for the prevention of DVT,
patient-controlled epidural anesthesia cannot be continued
postoperatively, and instead continuous femoral nerve
catheters are used.
29.
30. TOURNIQUET APPLICATION
routinely inflated over thigh during TKA to reduce intraop
blood loss, provide a “bloodless” field for cement fixation of
femoral and tibial components.
when deflated, blood loss usually continues for next 24 hours.
Tourniquets are usually inflated to a pressure 100 mm Hg
above pt's SBP for 1 to 3 hours.
Nerve injury after extended tourniquet inflation (>120
minutes) has been attributed to combined effects of
ischemia and mechanical trauma.
Peroneal nerve palsy, a recognized complication of TKR
caused by combination of tourniquet ischemia and surgical
traction.
When prolonged tourniquet inflations are required, deflating
the tourniquet for 30 minutes of reperfusion may reduce
neural ischemia.
31. cuff should be applied over limited padding.
Appropriate selection of tourniquet cuff size and inflation
pressure important to reduce risk of NM injury.
cuff should be large enough to comfortably circle the limb to
ensure circumferentially uniform pressure.
point of overlap should be placed 180 degrees from the
neurovascular bundle because there is some area of
decreased compression at the overlap point.
width of the inflated cuff should be >half the limb diameter.
Before tourniquet inflation, the limb should be elevated for
approximately 1 minute and tightly wrapped with an elastic
bandage distally to proximally.
32. duration of safe tourniquet inflation is unknown.
Recommendations range from 30 min - 4 hours.
5 min of intermittent perfusion between 1- and 2-hour
inflations, followed by repeated exsanguination through
elevation and compression, may allow more extended use.
Prolonged inflation / simultaneous release of 2 tourniquets -
significant acidosis, particularly in patients with an underlying
acidosis due to other causes eg.DM.
Even with RA, some pts complain of dull, aching pain or
become restless.
During surgery, however, opioids and hypnotics are usually
effective.
postulated that tourniquet pain is caused by the unblocking
of unmyelinated C fibers during recession of a neuraxial
block.
33. addition of narcotics to spinal or epidural anesthesia may
reduce tourniquet pain.
After tourniquet release, MAP falls significantly, partly owing
to release of metabolites from ischemic limb into circulation
& decrease in PVR.
advantages of SBTKR include exposure to risks of one
anesthetic, one postoperative course of pain, reduced
rehabilitation and hospitalization, and an earlier return to
baseline function.
SBTKA associated, however, with a higher incidence of
serious perioperative complications, including myocardial
infarction, fat embolization, and thromboembolic events.
34. Anaesthetic technique
General anaesthesia:
if general anaesthesia is indicated, bleeding may be
reduced by modest hypotension in carefully selected
patients, using volatile agents.
For hip arthroplasty, analgesia may be supplemented by
the use of a 3-in-1 (femoral/obturator/lateral cutaneous of
thigh) block.
Some anaesthetists favour a lumbar plexus block because
this also blocks the sciatic nerve, which has a component
supplying the hip.
For knee replacement, a 3-in-1 block combined with a
sciatic nerve block can be effective.
35. Regional anaesthesia is technique of choice because it:
reduce incidence of major periop complications with certain
surgical procedures, including DVT, PE, blood loss, respiratory
complications.
superior pain relief.
Peripheral nerve blocks employing long-acting anesthetics or
catheters may provide excellent intraop anesthesia and
superior postop analgesia.
preemptive analgesia.
manipulation of airway, & conscious patients can aid safest
& most comfortable positioning for surgery.
suggested that epidural anesthesia reduces venous pressure,
& this is significant factor in determining surgical bleeding,
decreased need for bank blood and associated transfusion
risks.
36. Sedation often desirable due to duration of operation,
intraop noise.
Oxygen should be administered throughout the operative
period.
As sedation deepens, airway obstruction or snoring may
occur (not a problem in the lateral position, but some supine
patients may require a nasopharyngeal airway).
37. Intraoperative problems
Patient position:
in the lateral position, there is a risk of excessive lateral
neck flexion and pressure on the dependent limbs.
Hypothermia:
orthopaedic theatres colder than other theatres, with a
higher velocity airflow leading to more rapid patient
cooling.
Hypothermia causes poor wound healing, infection,
coagulopathy and CVS dysfunction.
Fluid warmers, blankets and patient hats should be used
routinely.
38. Blood loss:
average blood loss in THR ranges from 300-1500 ml and may
double in the first 24 hours postop.
During TKR with an intraoperative tourniquet, most blood loss
occurs in the recovery area.
Careful fluid balance is essential because compensation for
hypovolaemia is poor in the elderly.
Cement reactions:
At the time of cementing, a drop in blood pressure and
oxygen saturation is often seen.
originally thought to be caused by a directly toxic effect of
the methyl methacrylate monomer component of the
cement, but now known to be caused by a shower of
microemboli of blood, fat or platelets forced into circulation
by high intramedullary pressure during cement packing and
prosthesis insertion.
39. Subsequent embolisation to the lungs produces a raised
pulmonary vascular resistance and reduction in left
ventricular return, resulting in hypotension.
microemboli are toxic to the lung parenchyma, causing
haemorrhage, alveolar collapse and hypoxia.
may be severe enough to cause cardiovascular collapse,
cardiac arrest and death.
Reactions are more common and more severe in bilateral
joint replacements
therefore vital to ensure that the patient is not hypovolaemic
before cementing.
40. Fat Embolism Syndrome
well-known complication of instrumentation of medullary
canal.
physiologic response to fat within systemic circulation.
clinical manifestations of FES include respiratory, neurologic,
hematologic, and cutaneous signs and symptoms.
presentation of FES can be gradual, developing over 12 to 72
hours, or fulminant leading to ARDS and cardiac arrest.
Gurd and Wilson in 1974 suggested major and minor criteria
to be used for the diagnosis of FES.
presence of any 1 major + 4 minor criteria and evidence of
fat macroglobulinemia was required for diagnosis of FES.
More recent investigations have indicated that quantity of
fat in circulation does not correlate with the severity of FES or
development of ARDS
41. Gurd's Diagnosis of Fat Embolism Syndrome
Major Features (at least one)
Respiratory insufficiency
Cerebral involvement
Petechial rash
Minor Features (at least 4)
Pyrexia
Tachycardia
Retinal changes
Jaundice
Renal changes
Laboratory Features
Fat microglobulinemia (required)
Anemia
Thrombocytopenia
High erythrocyte sedimentation rate
43. petechial rash is pathognomonic, usually present on
conjunctiva, oral mucosa, and skin folds of the neck
and axillae.
mild hypoxemia and radiologic evidence of bilateral
alveolar infiltrates, <10% progress to ARDS.
Neurologic manifestations – drowsiness, confusion,
obtundation and coma.
treatment of FES is supportive with early
resuscitation and stabilization to minimize the stress
response to hypoxemia, hypotension, and
diminished end-organ perfusion.
44. Deep Venous Thrombosis and Pulmonary Embolus
VTE major cause of death after surgery or trauma
to the lower extremities.
incidence of fatal PE highest in THR for hip fracture.
Effective thromboprophylaxis requires knowledge
of clinical risk factors in individual patients, such as
advanced age, prolonged immobility or bed rest,
prior history of thromboembolism, cancer,
preexisting hypercoagulable state, and major
surgery.
45. Antithrombotic Prophylaxis
LMWH started 12 hr before surgery / 12-24 hr after sx, or
4-6 hr after sx at half usual dose & then increasing to
usual high-risk dose following day
Fondaparinux (2.5 mg started 6-8 hr after surgery)
Adjusted-dose warfarin started preop or the evening
after surgery (INR target, 2.5; INR range, 2.0 to 3.0)
Intermittent pneumatic compression is an alternative
option to anticoagulant prophylaxis in patients
undergoing total knee (but not hip) replacement
46. Neueraxial Anesthesia and Analgesia in the
Orthopaedic Patient Receiving Antithrombotic Therapy
LMWH
placement should occur 10-12 hr after a dose.
Indwelling neuraxial catheters are allowed with once, not
twice daily) dosing of LMWH.
optimal to place/remove indwelling catheters in morning
and administer LMWH in evening to allow normalization of
hemostasis to occur prior to catheter manipulation
WARFARIN
Adequate levels of vit K-dependent factors should be
present during catheter placement and removal.
Pts chronically on warfarin should have normal INR prior to
performance of regional technique.
Monitor PT INR daily. Remove catheter when INR <1.5.
47. FONDAPARINUX
Neuraxial techniques not advised in pts who are anticipated
to receive fondarinux periop.
NONSTEROIDAL ANTI-INFLAMMATORY DRUGS
No significant risk of RA-related bleeding is associated with
aspirin-type drugs.
pts receiving warfarin or LMWH, combined anticoagulant
and antiplatelet effects may increase risk of periop bleeding.
other medications affecting platelet function such as
thienopyridine derivatives and glycoprotein IIb/IIIa platelet
receptor inhibitors should be avoided.
48. Postoperative Complications
Cardiac Complications
ACC/AHA guidelines recommend preop cardiac testing in
pts at increased risk on basis of clinical risk profile, functional
capacity, and type of surgery.
orthopedic surgery - intermediate-risk
Older pts have an increased risk of periop myocardial
morbidity and mortality after orthopedic surgery
possible reasons for this increased risk are as follows:
multiple medical comorbid conditions
limited functional capacity
some ortho procedures initiate a systemic inflammatory
response syndrome,
significant blood loss and fluid shifts
postop pain is a major management problem after
orthopedic surgery
49. All of these factors - stress response - tachycardia,
hypertension, increased oxygen demand, and myocardial
ischemia.
In pts in whom percutaneous coronary intervention involved
placement of stents - added risks of restenosis and thrombosis
if antiplatelet therapy discontinued before surgery -
increased periop bleeding if not discontinued.
In elderly pts, β-blockers should be continued periop with a
target heart rate less than 80 beats/min.
decision to initiate postop physical therapy and
rehabilitation, depends on whether there has been a
diagnosis of a postoperative myocardial infarction.
50. Respiratory Complications
elderly patients - progressive decrease in arterial
oxygen tension, an increase in closing volumes,
decrease of approx 10% in FEV1 with each decade
of life.
Due to alterations in chest wall mechanics,
exacerbated in arthritis.
hypoxia reflects respiratory changes caused by
age or embolization of bone marrow debris to the
lungs in these patients.
51. Neurologic Complications
confusion or delirium 3rd most common complication seen in
elderly patients
associated with an increased length of hospital stay, poor
functional recovery, progression to dementia, and increased
mortality.
Postop delirium manifests as
› attention and awareness deficits
› including acute confusion
› reduced ability to focus
› change in cognition
› irritability
› anxiety
› paranoia
› hallucinations.
52. develops acutely, but generally has a fluctuating course
over several days
major risk factors for postoperative delirium
› advanced age
› alcohol use
› preoperative dementia or cognitive impairment
› psychotropic medications
› multiple medical comorbid conditions.
› Perioperative events (hypoxemia, hypotension,
hypervolemia, abnormal electrolytes, infection, sleep
deprivation, pain, and administration of BZDs and
anticholinergic medications).
53. Aging alters pharmacokinetics and pharmacodynamics of
most medications, including anesthetics and analgesics.
may have longer and more profound CNS effects on elderly
patients.
Strategies used to reduce incidence of postoperative
delirium –
› include identifying risk factors
› vulnerable and affected patients
› preserving orientation
› early mobilization
› adequate pain control
› maintenance of normal sleep cycles
› avoidance of psychotropic medications
54. Postoperative management
Analgesia
Epidural analgesia
excellent, particularly in reducing quadriceps muscle spasm
following TKRs.
increased risk of urinary retention
catheterisation may cause a bacteraemia, increasing the risk
of prosthesis infection.
Patient-controlled analgesia is the choice in many institu-tions.
Intramuscular opiates may also be considered.
Regular paracetamol, 1 g/6 hours, should be given orally or
rectally.
55. NSAIDs used with caution, especially in elderly, owing to
increased risk of renal impairment.
Midazolam infusions or baclofen are sometimes required to ease
quadriceps muscle spasm.
Fluid balance:
stringent fluid balance monitoring is mandatory because blood
loss may double in the first 24 hours. Nausea may reduce the
patient’s oral intake.
Oxygen: perioperative ischaemia is common and generally
silent. Oxygen should be given for the first 72 hours
postoperatively.
56. Shoulder replacement
Monitoring and intravenous access
Std full patient monitoring is required
Large-bore IV access is made on the non-operative side
NIBP monitoring is instituted either on the non-operative side
with a non-return valve on IV line, or on the lower leg.
Anaesthetic technique
GA using an armoured tracheal tube and positive-pressure
ventilation.
Access to the patient’s head intraoperatively is extremely
restricted.
interscalene approach to brachial plexus blockade provides
excellent intraop & postop analgesia, improves operative
conditions, decreased blood loss, good muscle relaxation.
commonly gives a unilateral phrenic nerve palsy, seldom
causes alveolar hypoventilation, even in spontaneously
ventilating patients.
57. Patient position
placed in sitting position,
with bolster behind the
shoulder blades to improve
surgical access
Care should be taken to
ensure that there is no
excess strain on the lumbar
spine
torso should be securely
strapped
head ring
head securely fastened as
considerable pull and
movement at shoulder.
Access to airway difficult,
tracheal tube must
therefore be securely
taped in place.
eyes should be taped and
well padded.
58. Intraoperative problems
Elderly patients often have poor CVS compensatory
mechanisms while under GA.
At the start of the operation, while positioning patient, drop
in BP may accompany change from supine to sitting
vasopressors may be required.
at risk of air embolism from open veins at the operative site.
Postoperative management
extremely painful and, if pos-sible, interscalene block should
be used
supplemented with patient-controlled opiate analgesia.
Regular paracetamol and NSAIDs (in those in whom they are
not contraindicated) should also be prescribed.
59. Revision arthroplasty
As number of active elderly people increases, more patients
are returning for revision of earlier replacements.
As well as problems of TKR/THR, revision arthroplasties have
added complications associated with prolonged surgery and
high blood loss.
Preoperative preparation
anticipated blood loss - depends on the type of previous
prosthesis and the number of components being revised.
Pre-donation of autologous blood with acute nor-
movolaemic haemodilution
Platelets (often not immediately available) and clotting
factors may be required.
60. Monitoring and intravenous access
Invasive blood pressure and CVP should be considered
urinary catheter for hourly urine output measurements.
Anaesthetic technique
GA with CSE for pain, or CSE alone
Spinal anaesthesia is generally unsuitable for length of the
operation outlasts its effects.
Intraoperative problems
Temperature:
difficult to prevent perioperative hypo-thermia
long hrs, considerable volumes of intravenous fluid are
transfused.
Fluid warmers, hot air blowers, humidification systems and
patient hats
61. Blood loss
Pre-donation of one unit of blood, using acute
normovolaemic haemodilution, useful if pt has an
adequate starting haemo-globin level.
Platelets and fresh frozen plasma are often required.
Transfusion of pre-donated blood should wait until
surgical haemostasis is obtained.
Fluid balance should be guided by surgical blood
loss, central venous pressure trends (where
available), pulse, blood pressure and urine output,
with the aim of maintaining normovolaemia.
haemoglobin con-centration should be assessed
from blood gases.
62. Postoperative management
high dependency unit
Oxygen should be prescribed for at least 72 hours
Analgesia should be pro-vided by epidural infusion
with regular enteral paracetamol.
Close control of fluid balance is aided by the use of
cen-tral venous pressure monitoring and hourly
urine output measurement
Coagulopathies should be treated, but the
threshold to transfuse red cells depends, in part, on
the pres-ence of co-morbid medical conditions,
especially ischaemic heart disease.