Abstract: Objective: To explore the cause and prophylaxis of infected custom-made prosthetic knee replacement. （Methods: 8 ）patients with infected custom-made prosthetic knee replacement were selected to retrospectively analyze the possible cause during pre-, intra-, and post-operation. Results: All 8 patients were subjected to custom-made hinged prosthetics. The mean hospitalization time before operation was 18 days; the mean operation duration, length of incision, and drainage volume were 5.4h, 26cm, 445ml, respectively. The mean number of puncture or arthrotomy before primary arthroplasty was 2.6, and the mean number of puncture before diagnosis of infection of each joint was 5.5. Conclusion: Besides the predisposing factors of common total knee arthroplasty, the custom-made prosthetic knee replacement had longer incision, longer operation duration, more traumatic soft tissue, larger prosthetic volume,more numbers of puncture or arthrotomy before operation and diagnosis,and longer duration of drainage after operation; which put the patients at high risk of infection.