Excellent health is probably the biggest and best predictor of results after total knee replacement (TKR). Numerous studies show a direct link between health before an operation and results after the surgery.
Patients who rate their health as "poor" are four to five times more likely to die. This is true despite differences in background, disease severity, and other psychologic or social issues.
A recent study at the University of Kansas in Wichita confirmed these findings for TKR patients. Those who rated their health as "good" to "excellent" had the best outcomes. Their health status improved dramatically from before to after the operation. Joint stiffness, pain, and function were used to measure health status.
The authors of the study pointed out that all their patients came from one orthopedic practice. Their results may not be the same for other groups.