Total knee arthroplasty is a procedure in which the damaged cartilage in the knee is replaced with artificial bearing surfaces. Many patients present with significant arthritis in both knees and are deemed candidates for a knee replacement on both sides. Since there is a significant period of recovery associated with knee replacement surgery patients often desire simultaneous bilateral knee replacements. Controversy surrounds this topic and patients are often disappointed when their surgeon recommends against this approach and suggests staged knee replacements as an alternative.
The post-operative period after total knee replacement is very demanding on the patient. There is significant pain associated with a knee replacement and intensive physical therapy is required to achieve a good outcome. A perfectly performed knee replacement can end up with a poor result if time is not devoted to therapy. Most people who have had a knee replacement will agree that therapy is demanding and can be painful in the immediate post-operative period.
One concern with performing bilateral simultaneous knees is that the patient will not achieve their optimal outcome in terms of range of motion. The reason for this is that the amount of time spent in therapy is split between both knees. In theory, the amount of time spent in therapy should be doubled for patients who have had bilateral knees performed. This is usually not the case. For many patients it is simply too demanding and painful and therefore they are at risk of compromising their outcome. Admittedly this is not the case for everyone.
Bilateral simultaneous total knee arthroplasty is also associated with increased risk of morbidity and mortality when compared to a unilateral or staged procedure. A recent study1 published in a well respected Anesthesia journal looked at Nationwide Inpatient Data collected for the years 1998 to 2007 for patients undergoing elective bilateral simultaneous knee replacements. Patient demographics, including comorbidities, were analyzed and frequencies of mortality and major complications were computed. Subsequent multivariate analysis was conducted to determine independent risk factors for major morbidity and mortality. Patients of older age were disproportionately more affected by major morbidity and mortality. Patients with a higher prevalence of comorbidities, including chronic lung disease, congestive heart failure, and pulmonary hypertension were also shown to be at higher risk. Compared with patients in the age group between 45 and 64 years, those younger than 45 were half as likely to have a major complication or mortality. Patients over the age of 65 were more likely to have a major adverse outcome compared with those aged 45 to 65 years.
A number of comorbidities independently increased the risk for major morbidity and mortality. Pulmonary hypertension and congestive heart failure were associated with the highest odds. Other risk factors identified included a number of comorbidities suggesting decreased end-organ reserve such as kidney disease, neurologic disease, and chronic pulmonary disease. Obese patients, those with sleep apnea, chronic obstructive pulmonary disease (COPD), and patients with a history of pulmonary embolism are felt to be at high risk.
At present, the decision to proceed with bilateral simultaneous knee replacements is in the hands of the surgeon and the anesthesiologist. Given the controversy surrounding this issue, it seems inevitable that national guidelines will be established to guide the decision of whether to proceed with both knees at once or to stage the knee replacements. In the meantime, surgeons should proceed with caution, and remember the Latin phrase: “Primum non nocere.”
“First, do no harm.”
1. Bilateral total knee arthroplasty: risk factors for major morbidity and mortality. Memtsoudis SG, Ma Y, Chiu YL, Poultsides L, Gonzalez Della Valle A, Mazumdar M. Anesth Analg. 2011 Oct;113(4):784-90.
- Dr. Martin Gelbke