TOTAL KNEE REPLACEMENT
Total knee replacement surgery is considered for patients who have severe pain and functional disabilities related to joint sur-faces destroyed by arthritis (osteoarthritis, rheumatoid arthritis, posttraumatic arthritis) or bleeding into the joint, such as may re-sult from hemophilia. Metal and acrylic prostheses designed to provide the patient with a functional, painless, stable joint may be used. If the patient’s ligaments have weakened, a fully con-strained (hinged) or semiconstrained prosthesis may be used to provide joint stability. A nonconstrained prosthesis depends on the patient’s ligaments for joint stability.
Postoperatively, the knee is dressed with a compression ban-dage. Ice may be applied to control edema and bleeding. The nurse assesses the neurovascular status of the leg. It is important to encourage active flexion of the foot every hour when the pa-tient is awake. Efforts are directed at preventing complications (thromboembolism, peroneal nerve palsy, infection, limited range of motion).
A wound suction drain removes fluid accumulating in the joint. Drainage ranges from 200 to 400 mL during the first 24 hours after surgery and diminishes to less than 25 mL by 48 hours. Then the surgeon removes the drains. If extensive bleeding is anticipated, an autotransfusion drainage system may be used during the immedi-ate postoperative period. The color, type, and amount of drainage are documented, and any excessive drainage or change in charac-teristics of the drainage are promptly reported to the physician.
Frequently, a continuous passive motion (CPM) device is used. The patient’s leg is placed in this device, which increases cir-culation and range of motion of the knee joint. The rate and amount of extension and flexion are prescribed. Usually, 10 de-grees of extension and 50 degrees of flexion are prescribed ini-tially, increasing to 90 degrees of flexion with full extension (0 degrees) by discharge.
The nurse encourages the patient to use the device most of the time. The physical therapist supervises exercises for strength and range of motion. If satisfactory flexion is not achieved, gentle ma-nipulation of the knee joint under general anesthesia may be nec-essary about 2 weeks after surgery.
The nurse assists the patient to get out of bed on the evening or the day after surgery. The knee is usually protected with a knee im-mobilizer (splint, cast, or brace) and is elevated when the patient sits in a chair. The physician prescribes weight-bearing limits. Pro-gressive ambulation, using assistive devices and within the pre-scribed weight-bearing limits, begins on the day after the surgery.
After discharge from the hospital, the patient may continue to use the CPM device at home and may undergo physical therapy on an outpatient basis. Late complications that may occur include infection and loosening and wear of prosthetic components. Patients usually can achieve a pain-free, functional joint and participate more fully in life activities than before the surgery (Nursing Research Profile 67-2).