RESUMO
Objective: To investigate the effect of three-dimensional (3D) printing guide plate on improving femoral rotational alignment and patellar tracking in total knee arthroplasty (TKA). Methods: Between January 2018 and October 2018, 60 patients (60 knees) with advanced knee osteoarthritis who received TKA and met the selection criteria were selected as the study subjects. Patients were randomly divided into two groups according to the random number table method, with 30 patients in each group. The TKA was done with the help of 3D printing guide plate in the guide group and following traditional procedure in the control group. There was no significant difference in gender, age, disease duration, side, and preoperative hip-knee-ankle angle (HKA), posterior condylar angle (PCA), patella transverse axis-femoral transepicondylar axis angle (PFA), Hospital for Special Surgery (HSS) score, and American Knee Society (AKS) score ( P>0.05). Results: All incisions healed by first intention and no complications related to the operation occurred. All patients were followed up 10-12 months, with an average of 11 months. HSS score and AKS score of the two groups at 6 months after operation were significantly higher than those before operation ( P0.05). Postoperative X-ray films showed that the prosthesis was in good position, and no prosthesis loosening or sinking occurred during follow-up. HKA, PCA, and PFA significantly improved in the two groups at 10 months after operation compared with those before operation ( P<0.05). There was no significant difference in HKA at 10 months between the two groups ( t=1.031, P=0.307). PCA and PFA in the guide group were smaller than those in the control group ( P<0.05). Conclusion: Application of 3D printing guide plate in TKA can not only correct the deformity of the knee joint and alleviate the pain symptoms, but also achieve the goal of the accurate femoral rotation alignment and good patellar tracking.
RESUMO
PURPOSE: This study was undertaken to introduce a modified gap technique using manual distraction for achieving proper rotational alignment of the femoral components in total knee arthroplasty (TKA) and we compared the accuracy of the rotational alignment of the femoral components in TKAs when using a navigation system with that of another conventional technique. MATERIALS AND METHODS: We randomly used three different methods and implants (group 1: 3degrees external rotation from the posterior condylar axis method, group 2: a modified gap technique using manual distraction and group 3: a navigation system, Orthopilot(R)) in 92 patients. We measured the posterior condylar angles (PCA: the angle between the posterior condylar line and the transepicondylar axis) on computed tomography before and after surgery. RESULTS: The analysis showed no significant differences of the demographic data (age, height, weight, body mass index) and of the mean PCAs for the rotational alignment of the femoral components between the three groups (preoperative PCA: 5.45degrees vs. 5.34degrees vs. 5.24degrees, respectively; postoperative PCA: 1.91degrees vs. 1.17degrees vs. 1.37degrees, respectively, p>0.05). However, the conventional 3degrees external rotation method showed a higher frequency of outliers (p=0.028). CONCLUSION: The modified gap technique using manual distraction showed a higher accuracy of the femoral rotational alignment compared with that of the 3degrees external rotation method by reducing the outliers, and the modified gap technique using manual distraction showed similar results compared with those of the navigation method.