Joint Replacement - Patient Information

Before surgery:

After consultation with the doctor and the decision to do a joint replacement is made an extensive patient education is done regarding the surgery, anaesthesia and postoperative rehabilitation protocol which includes a short presentation about arthritis and joint replacement. A preoperative clinical evaluation is done followed by blood tests, chest radiograph and ECG are done followed by anaesthetic evaluation for fitness for anaesthesia. If required a cardiac evaluation is done. A dental check to rule out any focus of infection is done followed by culture of urine, blood and throat swab. Once all focus of sepsis is ruled out the date for surgery is fixed. Medications used for blood thinning like aspirin, clopidogrel or oral anticoagulants should be stopped one week before surgery. If the blood haemoglobin is low patient is put on iron and folic acid tablets to improve the blood haemoglobin. Higher the preoperative haemoglobin lower the requirement of postoperative blood transfusion. Patients are advised to stop smoking and avoid use of alcohol. The patient gets admitted the evening before surgery.

During surgery:

The day before surgery:                                                                                                      

The operative knee is cleaned with antiseptic solution and covered with a sterile drape. One unit of compatible blood is reserved. Reevaluation for any upper or lower respiratory infection is done. Infective endocarditis prophylaxis is started in patients with cardiac valve abnormalities and artificial heart valves. Diabetic patients are put on injectable insulin and the oral antidiabetic drugs are stopped. All patients are kept on 6 to 8 hours starvation. Any allergy to drugs is noted so that it can be avoided.

Day of surgery:

Patient is given a shower and premedication is given according to anaesthetic advice one and a half hours before surgery. Intramuscular Pethidine is usually given which acts as a sedative and anxiolytic.The regular dose of antihypertensive medicines, antiepileptics, antipsychotics, thyroid supplements are given. No antidiabetic drugs are given but fasting blood sugar and urine for sugar and acetone is done. The operative knee is again cleaned with antiseptic solution ( povidone iodine or chlorhexidine if allergic to iodine) and covered with a sterile drape.  With very dilute solution of antibiotic. Generally a second generation cephalosporin is used. A subcutaneous test dose of the prophylactic antibiotic is given. One dose of a proton pump inhibitor like Pantoprazole is given to prevent gastric irritation due to overnight starvation and concomitant NSAID use. Patient is shifted to the theatre and the procedure begins with starting of an intravenous cannula Low molecular weight heparin is started in patients with previous history of deep vein thrombosis(DVT), family history of DVT, cardiovascular problems like artificial heart valve, coronary bypass surgery, obesity and patients with expected delayed mobilization.

Combined Spinal with Epidural anaesthesia:

This is the most common form of regional anaesthesia used for all total knee replacements. The epidural is given in the operating table either in sitting position or lying position. It is given after a local anaesthetic dose at the lower lumbar spine. A small catheter is inserted into the epidural space and kept in situ. Through this a continuous infusion of local anaesthetic and opiod mixture can be given for pain relief. Once an epidural is given a spinal anaesthesia is given either through the same epidural needle or in a different level into the subarachnoid space. This causes complete reversible loss of sensation and motor power below the hips. Patient will be awake or sedated according to patient’s preference.

The advantage of this type of anaesthesia is the relative simple technique with minimal complication or side effect. It avoids the complications of general anaesthesia in elderly patients. It reduces the requirement of other pain relief medications. It allows continuous post operative pain relief with the use of infusion pumps which in turn allows early ambulation and accelerated recovery and early discharge.  

Pain management after total knee replacement:

A combined “multimodal apporoach” is used for pain management which includes preoperative NSAIDs, sedation, central and peripheral neuroaxial blockade with local anaesthetics and opiods, acetaminophen, NSAIDs and narcotics and physical therapy like cold pack application. With this combination therapy patient are being made to ambulate and knee mobilization exercises are started the very next day of surgery. With this protocol the patients have pain free recovery and early ambulation.
 
Knee replacement surgery:

It involves opening of the joint and clearing off the inflamed synovium and excess marginal bone (osteophyte).  The upper end of the leg bone (Tibia) is prepared to receive a metal platform called the tibial component and the lower end of the thigh bone (femur) is prepared a cup shaped metal alloy called femoral component. The entire joint is not removed but only the damaged surface is removed and is essentially a surface replacement. The bone cuts are done with aid of computer navigation. A special highly polished plastic insert (Ultra high molecular weight polyethylene) is fixed over the tibial platform and it articulated with the femoral component. Depending on the bone stock and the status of the supporting ligaments the type of femoral component and type of insert varies and the surgeon decides and fixes the appropriate type of joint suitable for the particular knee. The knee cap (Patella) is replaced with a dome shaped artificial polyethylene component depending on individual patient characteristics and status of the patellar articular surface. The components are fixed to the bone with help of bone cement (Polymethylmethacrylate). Once the new joint is put in and position confirmed with the computer (Navigation assisted joint replacement) the joint is washed and closed over suction drains. Subcuticular stiches are applied which doesn’t require a suture removal. Compression bandage is applied. The surgeries are done under pneumatic tourniquet control to avoid bleeding during surgery and facilitate good cement fixation. Patient is shifted to the postoperative ward for recovery and observation.

The day of surgery:

Patient is shifted to the room after the initial period of observation. Oral fluids and normal diet are started after four hours. Patient receives continuous epidural infusion for pain relief.  Active ankle and foot movements are encouraged and patient is allowed to change

First day after surgery:

The patient is allowed to sit up. Deep breathing exercises, active ankle movements and Isometric quadriceps exercise are encouraged. Check radiographs are taken. Passive knee bending exercises are started with a Continuous passive motion machine (CPM). Patient is made to stand and to walk with walker support depending on the pain and general condition. The physiotherapists will teach and assist the patients in doing the exercises. Patients are allowed to have normal diet. If the patient is diabetic insulin dose is given according to the blood sugar level and anti hypertensive medications are also restarted according to the blood pressure.
                                                                                   
Course in hospital:

As progressively wound healing occurs and physiotherapy is being done patient is relatively pain free and able to walk with walker support 10- 15 mts atleast four times a day. Patient is also able to bend the knee upto atleast 90 degrees.