F Knee (total knee replacement) arthroplasty
Total knee arthroplasty is the other frequently performed joint replacement procedure. A pneumatic tourniquet is typically used to provide a relatively bloodless surgical field. Nevertheless, blood loss as a result of total knee arthroplasty can be significant. During the procedure, the articulating surfaces of the femur and tibia are excised by precise angular cuts, and the patellar articulating surface is shaved, all to conform the bones to the inner surfaces of the prostheses. Both the femoral and tibial surfaces are covered with MMA cement, and the individual prosthesis components are forcibly seated with a mallet. The high-density polyethylene patellar component is cemented and seated with a viselike clamp. The medial and lateral menisci are replaced with a conforming wedge of high-density polyethylene.
2. Preoperative assessment
Assessment is routine, including history and physical examination. These patients have been diagnosed with arthritis of the knee.
a) Respiratory: These patients may have rheumatoid arthritis and associated pulmonary conditions. Pulmonary effusions may be present. Rheumatoid arthritis involving the cricoarytenoid joints may exhibit itself by hoarseness. A narrow glottic opening may lead to a difficult intubation. Arthritic involvement of the cervical spine and temporomandibular joint may also complicate airway management.
b) Cardiovascular: Depending on the severity of the arthritis, the patient may have a lowered exercise tolerance. Rheumatoid arthritis is associated with pericardial effusion. Cardiac valve fibrosis and cardiac conduction abnormalities can occur with possible aortic regurgitation. Test with an ECG and, if possible, an echocardiogram and cardiac nuclear imaging.
c) Neurologic: A thorough preoperative neurologic examination may yield evidence of cervical nerve root compression. If indicated, obtain lateral neck radiographs for the determination of stability of the atlanto-occipital joint.
d) Musculoskeletal: Positioning may be difficult because of pain and the decreased mobility of the joints.
e) Hematologic and laboratory: Obtain hemoglobin and hematocrit and other tests related to the history and physical examination.
