Application Of 3D Printing Patient-specific Instrumentation (PSI) In High Tibial Osteotomy (HTO)

Purpose: The purpose was to explore the clinic significance of using3 D printing Patient-specific Instrumentation(PSI)in high tibial osteotomy.Methods: From May 2016 to August 2017,30 cases with unilateral knee osteoarthritis(proximal tibia varus deformity),according to the double-blind method,were divided into observation group and control group,containing 16 cases in the observation group,completed HTO with the help of 3D printing PSI,and 14 cases in the control group selected HTO by free hand osteotomy,all patients were fixed with tibia proximal T-plate of Aplus.The operation time,the incision length and the number of X-ray exposure during operation were recorded.Besides,according to the imaging data after surgery,measure “eccentric angle” and the proximal tibia medial angle(Mpta),regular follow-up,comparison of the VAS score and HSS score between two groups after operation six months,evaluating the clinical effect of this study.Results: All patients in this study were able to be followed up on time,recovery smoothly after surgery,knee pain disappeared and no surgical complications occurred.In the observation group,the length of incision(7.18±0.29)cm,the number of X-ray exposure(14.94±1.73)times,the operation time(30.24±1.73)min and the eccentric angle(0.34 °±0.36 °),While the control group incision length(10.26±0.52)cm,X-ray exposure(23.29±1.38)times,operation time(40.13±1.64)min and eccentric angle(1.18 °±0.87 °).The incision length,X-ray exposure,operation time and eccentric angle in the observation group were all lower than those in the control group,there were significant difference(P <0.05).However,in the observation group,postoperative Mpta(88.20 ° ±1.10 °),VAS(0.75±0.58)points and HSS(86.31 ± 3.30)points after operation six months,in the control group,postoperative Mpta(88.10 °±1.08 °),VAS(0.86±0.66)pointsand HSS(85.86±2.88)points after operation six months.There was no significant difference between the two groups in the postoperative Mpta,VAS score and HSS score after operation six months(P> 0.05).Conclusion: High tibial osteotomy(HTO)is an effective method for the treatment of knee osteoarthritis(KOA)and is an important part of the ladder treatment of knee arthritis.HTO by free hand osteotomy and HTO with the help of 3D printing PSI can correct knee varus deformity,correcting alignment,treating the knee pain,restoring knee function,and obtaining satisfactory clinical effect.However,compared with HTO by free hand osteotomy,the application of 3D printing PSI to HTO has the advantages of shorter operation time,alignment corrected more accurate,less frequency of X-ray exposure during operation,shorten incision length and smaller soft tissue trauma.