Abstract
To consider bilateral simultaneous knee replacement, both knees must have significant structural damage. It is best if the patient can't decide which knee is more bothersome. In borderline cases, ask the patient to pretend that the worse knee is normal and if so, would they be seeing you for consideration of knee replacement on the less involved side. If the answer to this question is “yes,” consider the patient a potential candidate for bilateral knee replacement. If the answer is “no,” recommend operating only on the worse knee, and expect that the operation on the second knee can probably be delayed for a considerable period of time.
Strong indications for bilateral simultaneous TKA are bilateral severe angular deformity, bilateral severe flexion contracture, and anesthesia difficulties, i.e., patients who are anatomically or medically difficult to anesthetise, such as some adult or juvenile rheumatoid arthritis patients or patients with severe ankylosing spondylitis.
Relative indications for bilateral simultaneous TKA include the need for multiple additional surgical procedures to achieve satisfactory function and financial or social considerations for the patient. Contraindications to bilateral TKA include medical infirmity (especially cardiac), a reluctant patient, and a patient with a very low pain threshold.
When performing bilateral simultaneous TKA, both limbs are prepped and draped at the same time. An initial dose of an intravenous antibiotic is given (usually 1 gram of a cephalosporin) before inflation of the tourniquet. Surgery begins on the more symptomatic side or on either side if neither knee is significantly worse than the other. The reason for starting on the more symptomatic side is in case surgery has to be discontinued after only one procedure owing to anesthetic considerations.
After the components have been implanted on the first side, the tourniquet is deflated and a second dose of intravenous antibiotic is administered (usually 500 mg of a cephalosporin). After the joint capsule is closed and flexion against gravity is measured, one team completes the subcutaneous and skin closure on the first side while the other team inflates the second tourniquet and begins the exposure of the second side. When the second tourniquet is deflated, a third dose of antibiotic is given (usually 500 mg of a cephalosporin for a total dose of 2 g for both knees).
Because of concern about the potential for cross-contamination of the knee wounds when instruments used during the final stages of skin closure on the first knee are maintained on the field and used on the second knee, they should probably be handed off the field and outer surgical gloves changed.
Most patients will report after their complete recovery that they are glad they did both knees at the same time. A patient who has any uncertainty about proceeding with bilateral surgery should have only one knee done at a time. In many cases, the second side receives a “reprieve,” becoming more tolerable after the first side has been operated on.
