When a knee joint has worn out to the point where conservative treatments are unsuccessful, total joint replacement is indicated. Total joint replacement, also called joint arthroplasty reconstructs and recreates normal joint function and motion utilizing prosthetic materials. Knee replacement involves replacing the three surfaces of the knee with prosthetic materials or implants, which are well tolerated by the body. The three surfaces that are replaced are the femur, tibia, and patella. These implants are made out of metal and plastic and there are many differing sizes available so that each joint replacement can be customized to the patient’s own anatomy and size. One size does not fit all.
The implants are secured to a patient’s bone utilizing both cemented and cementless implant designs. Both types have worked very well our time. Cemented implants rely on “bone cement” to firmly fix the prosthesis to bone and are generally utilized in older patients who might have weaker bone secondary to osteoporosis. Cementless implants rely on bone to grow into the implant over time through special implant surfaces and are generally utilized in younger patients.
The benefits of knee replacement include pain relief, restoration of mobility and function, and improved quality of life. Knee replacement can also correct deformity, equalize leg lengths, eliminate limping and walking aids, such as a cane. In addition, knee replacement can allow a patient to decrease if not stop the use of arthritis medication.
Complications after knee replacement can include infection, prosthetic wear, hip dislocation, leg length discrepancy, nerve injury, incomplete relief of pain, fracture of bone, and heterotopic bone or extra bone formation. An experienced knee replacement surgeon utilizes special x-rays that will allow proper implant selection and size for your own knee problem to essentially eliminate a majority of these complications. Medical complications after surgery can include blood clots (both deep venous thrombosis and pulmonary emboli), heart, lung, and urinary tract complications.
The complications of knee replacement can largely be avoided with a thorough evaluation before surgery by both an experienced orthopaedic surgeon and internist or family physician. Problems identified prior to surgery need to be corrected or optimized before surgery is performed. Correction of dental or urinary tract infections before surgery with antibiotics can significantly reduce the risk of infection.
A person is a candidate for knee replacement when they have failed conservative treatment and have a condition of the knee that produces severe pain and disability. Furthermore, preoperative evaluation by a patient’s family physician is required to make sure there are no medical problems that would preclude them from being a surgical candidate, such as severe heart disease.
Preoperative Testing Requirements
A thorough history and physical examination with a family physician or internist is required before surgery. In addition, several routine blood tests, chest x-ray, and EKG (heart rhythm evaluation) are needed preoperatively. Special X-rays or other radiologic tests are sometimes required to provide your orthopedic surgeon with a more detailed evaluation of the anatomy of the knee so that proper implants may be available at your surgery.
Blood donation can be required depending on the complexity of the procedure required for your knee. Since knee replacement is an elective procedure and a tourniquet is utilized during the operation, blood donation is generally not required. However, if a patient has a complex knee problem or is to undergo revision knee replacement, Dr. Wardell generally asks the patient to donate one to two units of blood prior to the operation. A patient can only donate blood if they are deemed a candidate for blood donation. When both the patient and Dr. Wardell decide upon joint replacement as the best treatment option, our nursing staff will check your blood count in the office via a simple finger stick test. If a patient does not have a low blood count, blood donation can be recommended. If a patient has a low blood count or is anemic, then Dr. Wardell will recommend the use of a medication that stimulates blood cell production called Procrit. Procrit, or erythropoietin, has been around for a while and has been utilized in oncology and bone marrow transplant patients to reverse anemia. Anemia can cause fatigue, heart problems, shortness of breath, and lightheadedness. Both procedures are meant to decrease the need or requirement for blood from the blood bank. Blood bank blood can carry a small risk of patient exposure to hepatitis and HIV. Procrit has just recently been utilized in patients who are undergoing elective orthopaedic procedures where potential blood loss is expected. Dr. Wardell has utilized Procrit in many patients over the past year and has noted a significant decrease in the need for blood transfusion in joint replacement surgery.
Patients are generally in the hospital for 3 to 4 days after surgery. A patient as admitted the morning of surgery and physical therapy is initiated immediately after surgery. A knee motion machine, called a CPM, is started after surgery to assist the patient with range of motion. Spinal or epidural anesthesia is utilized in a majority of patients with sedative medications given during the operation. A patient is therefore sleeping but breathing on their own during the operation. This makes recovery easier and allows good pain control after the operation.
After the hospitalization for knee replacement, a patient is either discharged home or transferred to a rehabilitation facility. Most patients can be discharged home after knee replacement. Physical therapy and a visiting nurse come to the home to follow a patient’s progress closely after joint replacement. A prescription for pain medications and iron supplements by mouth are given to the patient just prior to hospital discharge. Walking aids, such as a walker or cane, is generally provided. A rehabilitation facility is generally utilized for patients that live alone or have limited family support in the area.
Recovery after knee replacement is most rapid during the first 4-6 weeks after surgery. However, most patients’ recovery can take approximately 3 months. At that point, patients who are laborers can generally return to work. A patient who has a more sedentary job can generally return to work earlier. Return to driving is generally 6 weeks after surgery. Maximal recovery can take up to a year dependent upon the procedure and the patient´s age.
Running is not advised after knee replacement and can increase the degree of implant wear and decrease the longevity of the implant.
Patients can generally return to an active lifestyle and participate in walking, golfing, swimming, biking, and bowling.
Knee replacement will generally last ten to fifteen years under average wear conditions. Patient factors that can accelerate wear are obesity, younger age and increased patient activity. Currently, there is no material utilized in joint replacement that lasts forever and does not wear. The prosthetic material does wear with time and at different rates in different people. Current research in joint replacement has focused on the modification of implant surfaces and materials to improve implant longevity. Ceramic on ceramic and newer durable plastics have shown promise but more research is needed before any conclusions can be made.
As time passes after joint replacement, wearing of the joint replacement surfaces can occur. When wear has progressed to a point where the prosthesis has loosened or a patient are having pain; revision joint replacement can be required. Revision joint replacement is a much more complicated procedure than the initial procedure and can require complex implants and bone graft to reconstruct the knee joint. Yearly office visits or follow-up with your surgeon is generally requested so the prosthetic implants and knee can be assessed for wear and function. In general, once a patient starts to have pain around an implant that was functioning well, significant prosthetic and bony changes have occurred. An x-ray and physical exam by your orthopaedic surgeon can easily assess the function of the prosthesis.
After knee replacement, yearly office visits or follow-up with x-ray evaluation of the implants are required. This allows your surgeon to diagnose and treat a problem earlier before loosening or prosthetic wear becomes catastrophic. Furthermore, Dr. Wardell has several patient outcome studies in progress and closely follows the outcomes and results of all his patients.