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TOTAL KNEE REPLACEMENT

Introduction
A TotalKnee Replacement (TKR) or Total Knee Arthroplasty is a surgery that replaces anarthritic knee joint with artificial metal or plastic replacement parts calledthe ‘prostheses'.
Theprocedure is usually recommended for older patients who suffer from pain andloss of function from arthritis and have failed results from other conservativemethods of therapy.
Thetypical knee replacement replaces the ends of the femur (thigh bone) and tibia(shin bone) with plastic inserted between them and usually the patella (kneecap).


Arthritis
Othercauses include:

  • Trauma (fracture)
  • Increased stress e.g., overuse, overweight, etc.
  • Infection
  • Connective tissue disorders
  • Inactive lifestyle e.g., Obesity, as additional weight puts extra force through your joints which can lead to arthritis over a period of time
  • Inflammation e.g., Rheumatoid arthritis

In an Arthritic Knee

  • The cartilage lining is thinner than normal or completely absent. The degree of cartilage damage and inflammation varies with the type and stage of arthritis.
  • The capsule of the arthritic knee is swollen
  • The joint space is narrowed and irregular in outline; this can be seen in anX-ray image.
  • Bone spurs or excessive bone can also build up around the edges of the joint

Thecombinations of these factors make the arthritic knee stiff and limitactivities due to pain or fatigue.


Diagnosis
Thediagnosis of osteoarthritis is made on history, physical examination &X-rays.
There isno blood test to diagnose Osteoarthritis (wear & tear arthritis).


Benefits
Thedecision to proceed with TKR surgery is a cooperative one between you, yoursurgeon, family and your local doctor.
Thebenefits following surgery are relief of symptoms of arthritis. These include

  • Severe pain that limits your everyday activities including walking, shopping, visiting friends, getting in and out of chair, gardening, etc.
  • Pain waking you at night
  • Deformity- either bowleg or knock knees
  • Stiffness

Prior tosurgery you will usually have tried some conservative treatments such as simpleanalgesics, weight loss, anti-inflammatory medications, modification of youractivities, canes, or physical therapy.
Oncethese have failed it is time to consider surgery. Most patients who have TKRare between 60 to 80 years, but each patient is assessed individually andpatients as young as 20 or old as 90 are occasionally operated on with goodresults.


Pre-Operation

  • Your surgeon will send you for routine blood tests and any other investigations required prior to your surgery
  • You will be asked to undertake a general medical check-up with a physician
  • You should have any other medical, surgical or dental problems attended to prior to your surgery
  • Make arrangements for help around the house prior to surgery
  • Cease aspirin or anti-inflammatory medications 10 days prior to surgery as they can cause bleeding
  • Cease any naturopathic or herbal medications 10 days before surgery
  • Stop smoking as long as possible prior to surgery

Day of your surgery

  • You will be admitted to the hospital, usually on the day of your surgery
  • Further tests may be required on admission
  • You will meet the nurses and answer some questions for the hospital records
  • You will meet your Anesthetist, who will ask you a few questions
  • You will be given hospital clothes to change into and have a shower prior to surgery
  • The operation site will be shaved and cleaned
  • Approximately 30 minutes prior to surgery you will be transferred to the operating room

Surgical Procedure
Each kneeis individual and knee replacements take this into account by having differentsizes for your knee. If there is more than the usual amount of bone loss,sometimes extra pieces of metal or bone are added.
Surgeryis performed under sterile conditions in the operating room under spinal orgeneral anesthesia. You will be on your back and a tourniquet applied to yourupper thigh to reduce blood loss. Surgery takes approximately two hours.
Thesurgeon cuts down to the bone to expose the bones of the knee joint.
Thedamaged portions of the femur and tibia are then cut at the appropriate anglesusing specialized jigs. Trial components are then inserted to check theaccuracy of these cuts and determine the thickness of plastic required to placein between these two components. The patella (knee cap) may be replaceddepending on a number of factors and depending on the surgeon's choice.
The realcomponents are then inserted with or without cement and the knee is againchecked to make sure things are working properly. The knee is then carefullyclosed and drains usually inserted, and the knee dressed and bandaged.


Post-Operation Course
When youwake, you will be in the recovery room with intravenous drips in your arm, atube (catheter) in your bladder and a number of other monitors to check yourvital observations. You will usually have a button to press for pain medicationthrough a machine called a PCA machine (Patient Controlled Analgesia).
Oncestable, you will be taken to the ward. The post-op protocol is surgeondependant, but in general your drain will come out at 24 hours and you will sitout of bed and start moving you knee and walking on it within a day or two ofsurgery. The dressing will be reduced usually on the 2nd post op day to makemovement easier. Your rehabilitation and mobilization will be supervised by aphysical therapist.
To avoidlung congestion, it is important to breathe deeply and cough up any phlegm youmay have.
YourOrthopaedic Surgeon will use one or more measures to minimize blood clots inyour legs, such as inflatable leg coverings, stockings and injections into yourabdomen to thin the blood clots or DVT's, which will be discussed in detail inthe complications section.
A lot ofthe long term results of knee replacements depend on how much work you put intoit following your operation.
Usually,you will remain in the hospital for 5-7 days. Then,  depending on yourneeds, either return home or proceed to a rehabilitation facility. You willneed physical therapy on your knee following surgery.
You willbe discharged on a walker or crutches and usually progress to a cane at sixweeks.
Yoursutures are sometimes dissolvable but if not, are removed at approximately 10days.
Bendingyour knee is variable, but by 6 weeks should bend to 90 degrees. The goal is toobtain 110-115 degrees of movement.
Once thewound is healed, you may shower. You can drive at about 6 weeks, once you haveregained control of your leg. You should be walking reasonably comfortably by 6weeks.
Morephysical activities, such as sports previously discussed, may take 3 months todo comfortably.
When yougo home you need to take special precautions around the house to make sure itis safe. You may need rails in your bathroom or to modify your sleepingarrangements, especially if they are up a lot of stairs.
You willusually have a 6 week check up with your surgeon who will assess your progress.You should continue to see your surgeon for the rest of your life to check yourknee and take X-rays. This is important as sometimes your knee can feelexcellent but there can be a problem only recognized on X-ray.
You arealways at risk of infections especially with any dental work or other surgicalprocedures where germs (Bacteria) can get into the blood stream and find theirway to your knee.
If youever have any unexplained pain, swelling or redness or if you feel generallypoor, you should see your doctor as soon as possible.


Risks and Complications

  • As with any major surgery, there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages
  • It is important that you are informed of these risks before the surgery takes place

Complicationscan be medical (general) or local complications specific to the Knee.
Medicalcomplications include those of the anesthetic and your general well being.Almost any medical condition can occur so this list is not complete.Complications include:

  • Allergic reactions to medications
  • Blood loss requiring transfusion with its low risk of disease transmission
  • Heart attacks, strokes, kidney failure, pneumonia, bladder infections Complications from nerve blocks such as infection or nerve damage Serious medical problems can lead to ongoing health concerns, prolonged hospitalization or rarely death

LocalComplications
Infection
Infectioncan occur with any operation. In the knee this can be superficial or deep.Infection rates vary. If it occurs, it can be treated with antibiotics but mayrequire further surgery. Very rarely your new knee may need to be removed toeradicate infection.
BloodClots (Deep Venous Thrombosis)
These canform in the calf muscles and can travel to the lung (Pulmonary embolism). Thesecan occasionally be serious and even life threatening. If you get calf pain orshortness of breath at any stage, you should notify your doctor.
Stiffnessin the Knee
Ideallyyour knee should bend beyond 100 degrees but on occasion, the knee may not bendas well as expected. Sometimes manipulations are required. This means going tothe operating room where the knee is bent for you and under anesthetic.

Wear
Theplastic liner eventually wears out over time, usually 10 to 15 years and mayneed to be changed.
WoundIrritation or Breakdown
Theoperation will always cut some skin nerves, so you will inevitably have somenumbness around the wound. This does not affect the function of your joint. Youcan also get some aching around the scar. Vitamin E cream and massaging canhelp reduce this.
Occasionally,you can get reactions to the sutures or a wound breakdown that may requireantibiotics or rarely, further surgery.
CosmeticAppearance 
The kneemay look different than it was because it is put into the correct alignment toallow proper function.
Leglength inequality
This isalso due to the fact that a corrected knee is more straight and is unavoidable.
Dislocation
Anextremely rare condition where the ends of the knee joint lose contact witheach other or the plastic insert can lose contact with the tibia (shinbone) orthe femur (thigh bone).
Patellaproblems
Patella(knee cap) can dislocate.  This means it moves out of place and it canbreak or loosen.
Ligamentinjuries
There area number of ligaments surrounding the knee. These ligaments can be torn duringsurgery or break or stretch out any time afterwards. Surgery may be required tocorrect this problem.
Damage toNerves and Blood Vessels
Rarelythese can be damaged at the time of surgery. If recognized they are repaired,but a second operation may be required. Nerve damage can cause a loss offeeling or movement below the knee and can be permanent.
Fracturesor breaks in the bone can occur during surgery or afterwards if you fall. Torepair these, you may require surgery.
Discussyour concerns thoroughly with your Orthopaedic Surgeon prior to surgery.


Summary
Surgeryis not a pleasant prospect for anyone, but for some people with arthritis, itcould mean the difference between leading a normal life or putting up with adebilitating condition. Surgery can be regarded as part of your treatmentplan—it may help to restore function to your damaged joints as well as relievepain.
TKR isone of the most successful operations available today. It is an excellentprocedure to improve the quality of life, take away pain and improve function.In general 90-95% of knee replacements survive 15 years, depending on age andactivity level.
Surgeryis only offered once non-operative treatment has failed. It is an importantdecision to make and ultimately it is an informed decision between you, yoursurgeon, family and medical practitioner.
Althoughmost people are extremely happy with their new knee, complications can occurand you must be aware of these prior to making a decision. If you areundecided, it is best to wait until you are sure this is the procedure for you.


Broken Bones and Injury
Common Knee Injuries
HamstringMuscle Strain
MuscleStrains in the Thigh


Fractures
Femur (Thighbone) Fractures in Adults
Femur(Thighbone) Fractures in Children GrowthPlate Fractures Proximal Tibia Fractures
Shinbone(Tibia) Fractures
StressFractures

Tears and Instability
Kneecap, Unstable
LigamentInjuries of the Knee
Meniscus,Tears of
PosteriorCruciate Ligament, Tears of

Pain Syndromes
Osgood-Schlatter Disease (Knee Pain)
Runner'sKnee (Patellofemoral Pain)
ShinSplints

Diseases and Syndromes
Bowed Legs
Bursitisof the Knee: Goosefoot (Pes Anserine)
Bursitisof the Knee: Kneecap (Prepatellar)
LimbLength Discrepency
Osteonecrosisof the Knee

Arthritis
Arthritis of the Knee
Osteoarthritisof Knee -- Social Impact
Osteoarthritisof the Knee - Frequently Asked Questions

Pain Syndromes
Burning Thigh Pain (Meralgia paresthetica)
CompartmentSyndrome
KneePain, Adolescent Anterior
Osgood-SchlatterDisease (Knee Pain)
Runner'sKnee (Patellofemoral Pain)

Treatment and Rehabilitation
Osteoarthritis: Surgical Treatment

Joint Replacement
Anesthesia for Hip and Knee Replacement Surgery
KneeReplacement and Implants
KneeReplacement, Cemented and Cementless
KneeReplacement, Minimally Invasive
KneeReplacement, Osteotomy and Unicompartmental Replacement (Arthroplasty)
TotalKnee Replacement

Nonsurgical Treatment
Care of Casts and Splints
Howto use Crutches, Canes, and Walkers
Viscosupplementationin Osteoarthritis of the Knee
Arthroscopy and Reconstruction
Anterior Cruciate Ligament Injury, Surgical Considerations in
KneeArthroscopy
MeniscalTransplants

Considerations
Deep Vein Thrombosis

Postoperative Care
Knee Arthroscopy, Exercise Guide
KneeReplacement - Exercise Guide
KneeReplacement, Activities After

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