Frequently Asked Questions
The best expertise in Orthopaedic & Arthritis care
The best expertise in Orthopaedic & Arthritis care
AGE OF PATIENT
Replacement of the hip or knee is generally recommended for patients over 60 years. The advanced age is not a bar to surgery. Many patients in their eighties successfully undergo joint replacement.
Many elderly patients have hypertension, diabetes, previous angioplasty or coronary bypass surgery, hypothyroidism, etc. Most of these patients can safely withstand hip or knee replacement. Preoperative assessment by a physician, cardiologist, endocrinologist, and others may be necessary to optimize the patient’s condition.
Joint replacement can be done at a younger age as well. This decision is taken after carefully considering the individual circumstances of the patient – single versus multiple joint involvements patient’s lifestyles and expectations effects of arthritis on career effects on marital life economic responsibilities and family commitments willingness to modify his/her lifestyle, etc. Some of these young patients will require revision surgery at a later date.
Control of hypertension, diabetes, asthma, etc. is necessary. Any infection in the skin, chest, urinary tract, teeth or ears, etc. should be treated before the operation.
Routine blood tests, ECG, chest–X-ray, and echocardiography are necessary. The patient is assessed by a physician, anesthetist and other specialists like cardiologist, pulmonologist, endocrinologist, etc. to optimize his/her condition before the surgery. Some medications may require modification before surgery. Two or three units of blood are reserved.
Both knees can be replaced together. This is done after careful evaluation of the patient’s condition. It avoids the need for another period of hospitalization and recovery. It also helps reduce hospital costs. Bilateral hip replacement can also be done, though this is rare.
Joint replacement is done usually under epidural anesthesia. It is also done under general anesthesia, spinal anesthesia or regional blocks. Epidural and regional anesthesia also provides excellent pain relief in the post-operative period. Regional blocks allow the patient to mobilize a few hours after the operation. The choice of anesthesia will be discussed by the anesthetist.
Total knee replacement involves removing the worn-out joint surfaces and implanting prosthetic device in place of the damaged surfaces. Only 8 -10 mm of the damaged bone surface is removed. The shape of the implants (prosthesis) closely matches the amount of bone removed. The femoral component is made of metal and has a bi-condylar shape. The tibial component consists of an oval-shaped metal tray with a highly cross-linked polyethylene inset. The patellar component is a circular polyethylene disc with a convex surface. Resurfacing of the knee cap is optional. The implants are fixed using acrylic bone cement.
In a total hip replacement, the socket is replaced by a hemispherical cup which has a metallic shell and an inner high-density-polyethylene liner. The head is replaced by a metal sphere supported on a tapered stem which fits into the bony canal of the femur. The implants have a specially textured surface which allows them to grip the bone. The fixation of the implant can be uncemented or cemented.
The surgery takes about 90 minutes. However, the patient is in the operation theatre for about three hours because of the time required for administration of anesthesia setting up the patient, equipment and surgical team and recovery from anesthesia, dressing and shifting the patient after the procedure.
POST-OPERATIVE COURSE AND LONG TERM CARE
The patient is kept under close observation for about 24 hours, either in the ICU or High Dependency Unit (HDU). The operated limb is supported in a bulky bandage or splint. One or two plastic tubes (drains) are placed during the surgery to drain excess blood from the knee. Antibiotics are given for 24-48 hours. Other medications for diabetes, hypertension, etc. are continued with some modifications. Anti-coagulants are started 6-8 hours after the surgery. Food intake is started after 4-6 hours.
Pain control is achieved by various means: infiltration of the soft tissues by local anesthetics and opiods, intravenous painkillers (regular doses or via Patient Controlled Analgesia device), epidural infusion, regional blocks, transdermal patches, etc.
Patients are made to sit up and walk with support on the next day. Partial weight-bearing is advised for the first 6 weeks when uncemented implants are used (hip replacement). Physiotherapy is started for regaining movements, improving muscle strength, improving chest function, and preventing venous thrombosis. The drains are removed after 24-48 hours. Most patients are able to walk the length of the hospital corridor by the fourth day. Some patients are also able to climb stairs at this time.
Patients are discharged 4-7 days after the operation. The wound is kept covered with a sterile dressing which should be kept dry. The sutures are removed between 10-14 days. Physiotherapy is continued at home for 4-6 weeks.
The patient is reviewed in the OPD at regular intervals. Staples are removed at two weeks. Recovery of movements and strength are monitored and appropriate modifications to physiotherapy or exercise programme are suggested. Initially, the patient is followed up every 3-6 weeks. After 6 months, yearly follow-up is advised.
These days, the trend is towards early discharge. Many patients can be discharged after 2-4 days. In carefully selected cases knee (and sometimes hip) replacement can be done as a day-care procedure. This requires a team of patient-care coordinator, home care nurses, physiotherapists, and other staff.
Prophylactic broad-spectrum antibiotics should be started before undergoing any dental, genito-urinary surgery or any major surgical procedure. Whenever there is any suspicion of infection anywhere in the body – like skin infection, urinary infection, ear infection, tooth infection, chest infection or systemic bacterial infections – the patient should seek immediate medical attention to start antibiotics and take other measures as required.
For the first 6 weeks, the patient should not engage in any vigorous activity with respect to the operated limb. After that progressive increase in the activity is permitted depending on the patient’s progress. Certain activities like sitting on the floor may have to be avoided. A western toilet with an elevated rim is recommended. Care should be taken to avoid falls and injuries.
Normal activities can be started after 6-8 weeks. The patient should not indulge in athletic activities, contact sports or high impact activities.
Joint replacement is one of the most successful procedures in the field of medicine. A well done hip or knee replacement generally lasts for about 15 years or more. This is influenced by the patient’s activity level, body weight, etc. among other factors.
There have been a number of recent reports of 95-98% twenty-year survival of the knee replacements. Advances in material sciences, implant design and surgical techniques are expected to improve these results.
Some patients have the misconception that after 15 or 20 years the hip or knee will stop working or they will be bed-ridden or the leg has to be amputated. This is utterly wrong. When the hip or knee fails it needs a revision hip or knee replacement, which is quite successful.
COMPLICATIONS OF JOINT REPLACEMENT
Any major surgery (not just joint replacement) carries certain risks. These are: bleeding, venous thrombo-embolism and anesthesia-related or medical-related – like disturbances of blood pressure or blood sugar, chest infection, and rarely, stroke, ischemic heart disease, etc. Pre-operative evaluation and treatment of these conditions helps to reduce (but not completely avoid) these risks.
Risks specific to joint replacement involve infection, injury to blood vessels or nerves, stiffness, persistent pain after surgery and early wear and aseptic loosening. In hip replacement, limb length discrepancy and dislocation are additional concerns. The rate of major complications like infection is around 1-2 percent.
Infection of the joint can occur immediately after surgery or at a later date. The risk of infection is higher in diabetic patients and those suffering from rheumatoid arthritis.
Preventive measures include pre-operative and post-operative antibiotics, strict discipline in operation theatre and the use of a dedicated clean operation theatre with laminar air flow facilities. Prevention of delayed infection is done by proper control of diabetes and other medical conditions and prompt treatment of infection in any part of the body like – teeth, urinary tract, etc.
Treatment of infected joint generally involves reoperation to wash the joint and remove any infected tissues. It may also be necessary to remove the prosthesis and implant a new one later. Resection arthroplasty (leaving the gap without re-inserting new implants) is an alternative for hip replacement. This results in shortening of the limb and a flail hip. In the knee, fusion of the joint (arthrodesis) is the salvage procedure.
Severe arthritis, collapse, developmental malformations, injuries or prior surgeries can result in severe deformities (usually shortening), soft tissue contractures and bony defects. It may not be possible to correct every aspect of the deformity by standard techniques and implants. Trying to do so may result in excessive surgical dissection, injury to muscles, weakness of stabilizing soft tissues; and tension on nerves leading to foot-drop, etc. In such situations it is preferable to accept some deformity and avoid these complications. This results in unequal leg length, which is treated by a shoe raise. Hip deformities, especially those due to congenital dysplasias or childhood diseases, can cause severe secondary deformities in the spine which are almost impossible to correct.
The femoral head can slip out of the socket resulting in dislocation. Dislocation mostly occurs in early post-operative period before the soft tissues have healed. It may occur repeatedly and impair the result of the surgery. Improper alignment of the implants or imbalance or weakness of soft tissues may be responsible for this condition. Treatment of acute dislocation involves relocation of the hip (sometimes under anaesthesia) and stabilizing the limb in traction (or in a brace) till the soft tissues heal. Recurrent dislocation needs proper evaluation and may require surgical intervention to correct it.
Direct injury to the nerves and blood vessels occurs very rarely. Indirect injury to the nerves is more common. The sciatic nerve can be stretched during hip replacement, especially if the patient has a severe pre-operative deformity or previous surgical scarring. Similarly, the peroneal nerve can be stretched during knee replacement. Both these injuries result in foot-drop deformity which usually recovers spontaneously. Persisting neurological deficit or significant injuries to blood vessels may require surgical exploration and remedial measures.
Clotting of blood in leg veins can cause swelling and pain in the leg. Propagation and dislodgement of the clot can cause blockage of the blood flow in the lungs – this can range from a mild to a life-threatening event.
This is prevented by the use of medications, mechanical devices (like stockings, foot pumps, etc.), epidural anesthesia, proper hydration during surgery and early mobilization of the patient.
Treatment of established thrombosis and embolism involves blood thinning medications and very rarely surgery.
This occurs in patients who have a poor range of motion before surgery and in those who do not adhere to the physiotherapy/exercise regimen. Treatment is by physiotherapy or manipulation under anesthesia. It should be understood that most artificial joints give a good range, but not the full range, of movements. This is because of design factors and the anatomical peculiarities of each joint.
Sometimes there is new bone formation in the soft tissues around the hip. This is called Heterotopic Ossification. Usually this does not cause any significant limitation of motion and the extra bone shrinks with time. Rarely the bone formation is excessive and causes severe restriction of movements. If detected early, it may respond to Indomethacin or low-dose radiation. Established cases may require surgical removal of the extra bone.
Slight discomfort at the operation site is common . It subsides within a few weeks or months. This pain is far less as compared to the pain of arthritis. Some patients experience more pain than usual. In the majority of these cases the pain is due to other problems like spondylosis, diabetic neuropathy or poor circulation in the limb. This is especially common in knee replacement. Careful evaluation reveals that the pain is not confined to the knee alone. In addition patient has tingling, numbness or burning sensations which suggest involvement of the nerves. Persistent pain could also be due to a problem in the joint itself – like a tight knee, overhanging implant, etc. In the hip joint, pain can arise from irritation of tendon (psoas tendon at the edge of the cup). Pushing the hip to extremes of movement can also result in pain.
Infection and aseptic loosening have to be ruled out when there is persistent pain. This may require X-rays, blood tests, imaging studies (radionuclide scans), aspiration, etc.
Over a period of time, the plastic, metal and ceramic articulations slowly wear out. The rate of wear is very low and the implant generally lasts around 15-20 years. Polyethylene wear is strictly not a complication but is an expected outcome. It is considered to be a complication when it occurs earlier. Excessive stress like obesity, high impact activities, sports, etc. will lead to early wear.
The fixation of the implant to bone can become loose as a result of mechanical forces or as a reaction to wear debris particles. A variable amount of bone gets resorbed in the process. Wear and aseptic loosening are treated by revising the joint replacement.
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