Total Knee Replacement: One at a Time? Or Both Together?

Patients with painful arthritic knees may wrestle with the decision to have them replaced one at a time (two separate surgeries and rehab) or both at the same time. The proposed advantages of the simultaneous bilateral knee replacements are decreased costs and shorter recovery time. The results (or outcomes) are just as good between the staged (one-at-a-time) approach and the simultaneous (both done together) method.

Researchers at the University of North Carolina (Charlotte) and the OrthoCarolina Research Institute (also in Charlotte, North Carolina) took on the task of doing a cost-utility and cost-effectiveness study. They used the Nationwide Inpatient Sample data to compare the results of 24,574 cases of simultaneous knee replacements with 382,496 patients who had unilateral (one-at-a-time) procedures.

Measures used to compare the outcomes included perioperative complications (minor, major, and mortality), hospital costs, rehabilitation costs, anesthesia costs, and health utilities (visits to the surgeon, primary care physician, physical therapist). Most striking was the difference in overall costs: $43,401 for simultaneous procedures compared to $72,233 for staged procedures (almost double).

Previous studies have reported more complications with simultaneous knee replacements compared with staged procedures. Problems such as gastrointestinal complications, blood clots, heart attacks, and even death can occur. But this study found no difference in the overall rate of complications between these two approaches.

In fact, for minor, major and in-hospital mortality (death), simultaneous procedures had lover complication rates. For example, the major complication rate for the staged group was 2.36 per cent compared with 1.49 per cent among the simultaneous group. The minor complication rate was 8.98 per cent (staged group) versus 6.84 per cent (simultaneous group).

In summary, with almost six billion dollars being spent on total knee replacements each year in the United States, this cost analysis shows the economic benefit of simultaneous procedures. Replacing both knee joints at the same time is both safe and effective. Data analyzed provides quality comparative evidence that can guide physicians and patients when faced with this decision.

This information may be helpful to the five million adults who suffer from severe knee osteoarthritis who are looking for improved quality of life and function. Although there is a risk of increased complications with simultaneous procedures, exposure to only one anesthetic, decreased recovery time, shorter hospital stay, and lower costs may outweigh the risk. Older adults with serious health problems may not qualify as candidates for the simultaneous replacement of both knees.