The application of Patient specific Instrument （PSI ）in total knee arthroplasty with valgus knee

To invest the auxiliary role of Patient specific Instrument(PSI) used as osteotomy guide plate in total knee arthroplasty(TKA) with valgus knee.Hypotheses: PSI osteotomy guide plate is applicable for total knee arthroplasty with valgus knee.Methods: A retrospective analysis was performed on 21 patients with valgus knee, including 5 males and 16 females, who underwent TKA in joint surgery department I of ZhengZhou Orthopaedic Hospital from March 2016 to February 2018. All the operations were performed with the assistance of PSI, and the radiographic and clinical evaluations including femoral tibial joint ectropion angle(FTA) before and after operation, range of motion(ROM) and the Hospital for Special Surgery (HSS) knee score were reviewed, and surgical complications were recorded.Results: All the 21 patients werefollowed up for 10 ˜ 26 months (mean 16 months).All the incisions healed by first intention. The FTA was reduced significantly to 6.3 °±1.2° after operation from 17.6 ° + 5.7 °(P < 0.05), the ROM was improved significantly from preoperative 71.3° ±5.8° to postoperative 102.4°±7.5° (P < 0.05), the HSS score at the last follow-up was improved from 38.2±5.7 to 87.5-3.5(P < 0.05). During the follow-up, no complications such as infection, loosening, sinking and valgus were observed.Conclusion: Providing accurate osteotomy, effective correction of the force line, simple operation and satisfactory clinical effect, the PSI osteotomy guide plate is applicable for total knee arthroplasty with valgus knee.