Presented By: Moderated By

Dr.Debashish Mondal Dr.I.Begum

1st year PGT Associate Professor

Dept. of Anesthesiology and Critical care

Silchar Medical College and Hospital

Hip replacement is also known as “ARTHROPLASTY”.

ARTHROPLASTY-it is a reconstructive surgery to restore the joint motion and function and to relieve pain.It generally involve the replacement of bony joint structure by a prosthesis.

It is the most common orthopaedic surgery.

Hip replacement surgery can be performed as :

1.Total hip replacement-it consist of replacing both femoral head and acetabulam.

2.half(hemi) replacement-it consist of replacing femoral head in general.

CHARNELEY(1979)-revolutionized the management Of the arthiritic hip with development of low friction

arthroplasty.

His 3 major contribution to the evolution of hip replacement were:

1.the concept of low friction torque arthroplasty.

2.the use of acrylic cement to fix the components.

3.the introduction of high density polyethylene as a bearing material.

Attached to hip joint is a strong,loose,fibrouscapsule which permits free movement of hip joint.

It attaches proximally to acetabulam and transverse acetabular ligament.

Some parts of fibrous capsule are thicker than other and are called ligaments.

Femoral nerve

Obturator nerve

Superior gluteal nerve

Nerve to quadratus femoris.

For patients with unremitting pain and irreversibilydamaged joints as in 1.severe osteoarthiritis.

2.rheumatoid arthiritis.

Selected fracture-femoral neck fracture.

Failure of previous reconstructive surgeries(osteotomy,cuparthroplasty,femoral neck fracture complications-non union,avascular necrosis)

Congenital hip disease.

Pathologic fracture from metastatic cancer.

Joint instability

1.osteoarthiritis-60%

2.rheumatoid arthiritis-7%

3.fracture/dislocations-11%

4.aseptic bone necrosis-7%

5.revision arthroplasty-6%

6.other-9%.

Common in weight bearing joints like hip and knee jts.Also seen in spine and hand.

Both male and female affected but commoner in post menopausal women as there is loss of oestrogenic support.

Osteoarthiritis can be primary and secondary.

Primary-cause is unknown,more commoner than secondary.common in elders where there is no previous pathology.it may be due to wear and tear occuring in old age in wt. bearing joint.

Secondary-due to predisposing cause like injury,previousinfection,RA,CDH,deformity,obesity,hyperparathroidism.

Pathology-non inflammatory degenaration of articular cartilage with exposure of bone surface which becomes hard and polished called eburnation of bones,there is osteophyte formation at the margin of articular cartilage which projects into the joint.

Pain in affected joint aggravated by movement(most common symptom)

Morning stiffness more than 1hrs.

Relative incidence of joint involvement in RA:-

Mcp and pip joints of hand ,mtp of feet-90% Knees,ankles ,wrist-80% Elbows-50% TMJ,Acromioclavicular joint-30%

HEART-pericarditis,endocarditis,LVF,valvulitis,atherosclerosis leading to MI.

LUNGS-Pleural effusion,pneumonitis,pleuropulmonary nodules ,ild

CNS-

Peripheral neuropathy,cord compression from atlantoaxial/midcervical spine sublaxation,entrapment neuropathies.

HEMATOLOGICAL-normocytic normochromic anaemia,leucocytosis/leucopaenia,thrombocytosis.

Feltys syndrome-chronic nodular Rheumatoid arthiritis+splenomegaly+neutropenia.

Most common extraarticular manifestation is constituitional symptoms followed by rheumatoid nodules.

Pts likely to get extraarticular manifestation shows following:

1.high titres of RF/ANTI-CCP 2.HLA DR4+ 3.male gender 4.early onset disability 5. history of smocking

Absolute:1.pt. with unstable medical illness that would significantly increase the risk of morbidity and mortality.

2.active infection of hip joint or anywhere else in the body.

Relative:1.any process that is rapidly destroying bone eg-neuropathic joint,generalized progressive osteopenia.

2.insufficiency of abductor musculature.

3.progressive neurological disorder.

The prosthetic implant must be durable.

They must permit extraordinary low friction movement at the articulation.

They must be firmly fixed to skeleton.

They must be inert and not provoke any unwanted reaction in tissue.

The prosthesis are of various designs and may be fixed to the remaining bone by cement,pressfit or bone ingrowth.

Selection of prosthesis and fixation technique depends on patients bone structure,joint stability,other individual characteristics -age,weight,activity level.

Bone cement-methylmethacrylate is an acrylic polymer that has been used extensively in orthopaedicsurgeries for approx,30 yrs.

Its use is associated with potential for hypoxia,hypotension and cardiovascular collapse including cardiac arrest.

The most likely cause is fat embolisation resulting from raised intramedullary pressure due to cement expanding as it hardens.

Direct toxic effect of cement is also possible.

Problem typically occur soon after cement implantation but maynot occur until the end of operation when the hip is relocated and emboli are dislodged from a previously obstructed femoral vein.

PREVENTION AND TREATMENT

1.suction applied to bone cavity to evacuate air and fat during cement insertion dramatically reduces the incidence of complications.

2.measure blood pressure frequently during this time.

3.ensure adequate blood volume prior to cementing.

4.increase the inspired o2 conc. Prior to cementing.

5.stop N2O (nitrous oxide).

6.alpha agonist(eg.methoxamine) to treat hypotension.

Pts are usually elderly has associated systemic illness such as HTN,IHD,COPD,Renal impairment, therefore careful history taking and risk assessment is vital.

Cardiopulmonary reserve is difficult to assess in such patients as exercise tolerance is usually limited by hip disease in such paients.

Impaired renal function due to age,htn or chronic use of NSAIDS.

Musculoskeletal involvement-in RA pts cervical spine and TMJ may be involved-this may be significant enough to impair GA if required.regional anesthesia is usually best in such cases.

Drugs-pts may be taking drugs which have implications for regional anesthesia such as warfarin/aspirin/clopidogrel.cvs drugs such as b-blockers,ace-inhibitors.beta blockers should be continued perioperatively,ACE inhibitors may be stopped if a regional technique selected.

General examination-important factors which may influence choice of anesthesia-pt weight,shape of back,spinal deformity if any(scoliosis/kyphosis).

INVESTIGATIONS –all patients should have the following investigations done:

1.Full blood count

2.serum urea,creatinine

3.serum electrolytes(Na+,k+,ca2+,cl-)

4.ECG

5.Chest x ray

6.coagulation profile.

7.blood groping/save or crossmatched 2 units of whole blood or packed rbcs.

8.Random blood sugar.

Special invectigation- echocardiography in pt. above 60yrs or in case of clinical indication.

Total hip replacement can be performed under general,spinal,epidural anesthesia and often a combination of techniques used.

There is no evidence of difference in mortality between techiques.however REGIONAL ANESTHESIA has significant advantage over GENERAL ANESTHESIA.

Advantages of RA-1.reduce blood loss during surgery,thus reducing need for blood transfusion.

2.decreases bleeding at operative site,improvescement bonding and shortens surgical time.

3.reduces incidenc of DVT and PE (Pulmonary embolism).

4.avoids effect of general anesthesia on pulmonary function.

5.provides good early postoperative analgesia. 6.cost effective.

N.b-the reduced blood loss in SA as compared to GA is due to reduction in arterial and venous pressure resulting from sympathetic blockade,which give rise to less arterial ,notably less venous oozing from surgical site.

1.Monitoring-all patient should be monitored with blood pressure,ecg,pulseoximetry.

Capnography,inspired oxygen,volatile agent analysis and airway pressure monitoring are indicated for general anesthetic.

2. I.v access-16-18 g cannula.For patient undergoing surgery in lateral position placement of cannula in lower arm has the advantage of keeping upper arm free for blood pressure cuff.

3.temperature maintenance-keep pt warm by forced warm air or by warmed I v fluids/covering exposed area if possible.activelywarming the pt. reduces intraoperative blood loss, hypothermia can lead to poor wound healing,infection and cardiovascular dysfunction.

4.positioning of patient-most surgery takes place in lateral position.there is a risk of excessive lateral neck flexion and pressure in dependant limbs.

Also care must be taken to ensure that anterior stabilising post used to hold the patient in lateral

position does not compress the femoral triangle.

5.ensure adequate blood pressure being maintained,hypotension contraindicated.

6.ensure adeqaute volume filling prior to cementing.

7.antibiotic prophylaxis is required.

1.spinal anesthesia in hip replacement surgery-ensure adequate hydration prior to performing spinal anesthesia and cementing.

2.for single shot spinal anesthesia-3ml bupivcaine0.5% depending on patients size.opiates may be added for more prolonged analgesia and to cover longer surgery time(upto 3 hrs).

Opioid DoseDuration of action

Diamorphine 250 mcg 10-20 hrs

Morphine (preservative free)

100-200mcg 8-24 hrs

Fentanyl 25mcg 1-4 hrs

Sedation is often desirable due to length of operation,intraoperative noise,and pt.request

Pt in lateral position may become restless and uncomfortable because of pain in dependantshoulder.

Drug used for sedation-intermittent doses of midazolam/tci(target controlled infusion) of propofol with supplemental oxygenation.Buprenorphine,ruffy also used with spinal anesthetic as analgesic and to cover the duration of surgery.

2.general anesthesia in HRA-occasional, for supine position consider LMA with light general anesthesia

Advantages of general anesthesia in HRA: 1.safer for patient with fixed cardiac output conditions

such as aortic stenosis. 2.patients preference 3.less likely to require urinary catheterisation.

N.b-spontaneous ventilation with a LMA or ventilation via ET –TUBE is appropriate during GA.

Analgesia may be supplemented by peripheral nerve block enabling reduced use of opiods.

Epidural analgesia may be considered for longer,morecomplex surgery but is not usually required for postoperative analgesic requirement in an uncomplicated hip replacement surgery.For longer surgeries a combined spinal-epidural technique can be applied.

The hip joint is innervated by femoral,sciatic,obtur ator nerves with skin and superficial tissues receiving

branches from lower thoracic nerves.

Consequently no single peripheral nerve block is sufficient for hip replacement.

A femoral 3 in 1 block or a psoas lumbar plexus block may be performed if central neuraxial blockade is contraindicated.A 3 in one block is used to block femoral nerve,lateral femoral cutaneous nerve,obturator nerve.

. These techniques provides comparable analgesia and

can be used to supplement GA.

1.Patient on bed in supine position with legs abducted using a pillow to prevent dislocation of prosthesis.

2.Anti thrombolytic prophylaxis is important as DVT is the most common serious post op complication usually effecting calf muscles and responsible for 50% post op mortality within 3 months of surgery. It can be prevented by early mobilization,pneumatic compression boots/stockings,pharmacologic prophylaxis with low dose heparin,aspirin,warfarin,dextran.Early detection is essential and diagnosed by duplex doppler ultrasound.

Fatal pulmonary embolism can be seen in 2% cases.

3.Oxygen therapy for upto 24 hr is advisable in most patients.

4.haemoglobin should be checked 24 hr postop and treated with either blood transfusion /iron supplementation as indicated.

5.For analgesia-Simple IM opiods with regular paracetamol or NSAIDS is sufficient.If an epidural has been inserted a postop infusion is rarely necessary and needs to cease prior to mobilisation.

Blood loss varies significantly on an avg-300-500ml.It is also sffected by anesthetic technique.

The decision to transfuse is multifactorial and includes general finess,continous surgical losses and local practice.

The benefits of epidural analgesia may be limited to early postop period only(upto 6 hr).

Use of bone cement is associated with 3 times higher risk of PE.

Use of unfractionated heparin is associated with 6 fold higher risk for DVT compared with LMWH.

Early complications:

1.nerve injury(sciatic,femoral,peroneal nerve may get injured from direct surgical trauma,traction,pressure from retractors,thermalor pressure injury from bone cementing).

2.Haemathrosis/vascular injury.

3.Thromboembolism.

4.Bladder injuries and uti.

Late complcations: 1.loosening of prosthesis. 2.osteolysis. 3.heterotrophic calcification. 4.component failure.

COMPLICATIONS INDEPENDENT OF TIME: 1.Infection 2.dislocation 3.trochanteric non union 4.femoral fracture 5.limb length discrepency

Geriatric patient for joint replacement surgeries offer a great challenge to anesthesiologist.

A careful preoperative examination,preoperativeoptimization,safe intraoperative anesthetic technique,good post operative pain relief,goodpost operative follow up with rehabilitation would aid in decresing morbidity in these patients.