A novel integrated patient specific instrumentation system and its application for total knee arthroplasty

Objective To study the accuracy of preoperative planning and postoperative satisfaction of prosthesis position by applying the personal surgical cutting guide (PSCG) to total knee arthroscopy (TKA) based on 3D printing technique. Methods In this randomized study, 20 patients were selected from August 2014 to October 2015, who were randomly divided into two groups. In PSCG group, 4 males and 6 females were enrolled, with a mean age of 70.9±6.69 (from 59 to 78) years. In conventional instrumentation group, 2 males and 8 females were enrolled, with a mean age of 69.9±6.35 (from 58 to 77) years. The conventional instrumentation group was treated with conventional TKA, while the PSCG group was treated with personal surgical cutting guides. Then the knee valgus angle of patients, the angle between prosthesis components on the coronal and the sagittal plane of two groups were evaluated. Subsequently the correlation of the actual osteotomy amount, the valgus angle, caster angle, external rotation angle between intra- and preoperative planning were compared in the PSCG group. Results Compared with the ideal value of each angle, the mean deviation of the hip-knee-ankle angle 0.77°±0.51°, frontal femoral component angle 0.37°± 0.53° and frontal tibial component angle 0.11°±0.24° showed statistically significant difference between two groups (P 0.05). The actual osteotomy amount, the valgus angle, caster angle, external rotation angle correlated well between intra- and preoperative planning (t=-2.547, 3.864, 0.537, -0.040, -1.290,P >0.05). Conclusion TKA assisted by PSCG can make lower extremity alignment and accuracy of prosthesis implantation more accurate compared with conventional TKA, especially in hip-knee-ankle angle, frontal femoral component angle and frontal tibial component angle. Key words: Arthroplasty, replacement, knee; Individuality; Imaging, three-dimensional