Many patients will attempt high-impact loading activities after total knee arthroplasty. This study analyzed the clinical and radiographic results of these high-demand sports patients. A total of 31 patients (33 knees) were identified who participated in high-impact sports on average 4 times per week (range, 1-7 times per week) for a mean of 3.5 hours per week (range, 1 to 10 hours), including jogging, downhill skiing, singles tennis, racquetball, squash, and basketball. At 4 years mean follow-up (range, 2-9 years), 32 of 33 knees had successful clinical and radiographic outcomes. Overall satisfaction was a mean of 9.1 points on a scale of 0 to 10 points. These results indicate that some patients will participate in high-impact sports and enjoy excellent clinical outcomes at a minimum 4 years after surgery.