| Background: Total knee arthroplasty(TKA)is the most effective treatment for end-stage knee osteoarthritis(OA).There are many reasons for the failure of TKA,among which the instability of the artificial joint caused by the wrong rotational axis of the knee joint is an important reason for the failure.The rotational axis of flexion and extension of the knee joint fluctuates near the surgical transepicondylar axis(s TEA),which can be approximated as the rotational axis.The accuracy of s TEA was determined to be low by touching the ends of the medial and lateral collateral ligaments(the lowest point of the sulcus of the medial epicondyle and the highest point of the prominence of the lateral epicondyle).Intraoperative navigation technology will be able to avoid the human error to some extent,but it can prolong the operation time and increase the risk of bleeding and infection.With the rapid development of computer aided design(CAD)and 3D p rinting(3DP)technology,patient-specific instrumentation has realized industrialization and modularization in design and manufacture,and has been widely applied in clinical practice.Objective: In this study,combined with CAD technology and 3DP technology,according to the anatomical axis of the femur and sTEA of patients,a personalized guide for assisting intramedullary guide and s TEA positioning was designed,studying its application in TKA,short-term clinical efficacy,improvement of femoral rotation alignment and patellar tracking,and gait analysis of the postoperative patients.Methods: 1.The application of 3DP guide in TKA and its short-term clinical effect: 60 patients with TKA indications were selected between January 2018 and October 2018.There were 20 cases of rheumatoid arthritis(RA)and 40 cases of OA.The patients were divided into the traditional group and the 3DP guide group with 30 cases in each one,and underwent the traditional TKA and the TKA assisted by the 3DP guide.After the surgery,the position of the prosthesis was rechecked,and the intraoperati ve blood loss,operation time,postoperative drainage volume,removal and drainage time of the two groups of patients were recorded and compared,as well as the preoperative and postoperative HKA,HSS and KSS scores.2.Study on the effect of 3DP guide on improving femoral rotation alignment and patella tracking in TKA: From January 2018 to October 2018,60 cases(60 knees)of patients with advanced knee OA receiving TKA treatment were selected as the study objects,and were divided into 2 groups by random number table method,with 30 cases in each group.The 3DP guide group received TKA assisted by 3DP guide,and the control group received traditional TKA.There were no statistically significant differences in gender,age,course of disease,profile,preoperative HKA,PCA,PFA,HSS score and AKS score between the two groups.Six months after surgery,HSS score and AKS score were compared between groups and within groups.HKA,PCA and PFA were compared between groups ten months after surgery.3.Gait analysis:(1)Twenty female patients(20 knees)with knee OA associated with varus deformity who received 3DP guided assisted TKA treatment from January 2018 to October 2018 were selected as the study subjects(surgical group).Twenty healthy female volunteers were selected as the control group according to their ages and sides.Vicon was used for gait analysis 6 months after surgery,compare two groups of kinematics parameters [velocity,cadence,stride length,maximum knee flexion angle(stance),minimum knee flexion angle(stance),maximum knee flexion angle(swing),mean hip rotation angle(stance),mean ankle rotation angle(stance)];(2)From January 2018 to October 2018,30 patients(30 knees)who received 3DP guide assisted TKA were selected,and 60 patients(60 knees)who had received traditional TKA during the same period were selected(According to the postoperative CT measurement results,the patients were divided into " excessive extorsion group " and " insufficient extorsion group ",each with 30 cases)were selected.Gait analysis was performed on the 3 groups one year after surgery,and kinematic,kinetic and spatiotemporal parameters were compared between the groups.Results: 1.The application of 3DP guide in TKA and its short-term clinical effect: The 3DP guide could assist the femoral intramedullary guide accurately,and the depth of intramedullary guide was shallow.Intraoperative blood loss and postoperative drainage volume in the 3DP guide group were less than those in the traditional group,and the operation time was longer than that in the traditional group,with statistically significant differences(P<0.05).There was no significant difference in postoperative drainage time between the two groups.All patients were followed up for 7-12 months,with an average follow-up of(9.0±3.9)months.HKA,HSS and KSS scores of the two groups at 6 months after surgery were all improved compared with those before surgery,and the differences were statistically significant(P<0.05).There was no significant difference in HKA,HSS and KSS scores between the two groups at 6 months after surgery.2.Study on the effect o f 3DP guide on improving femoral rotation alignment and patella tracking in TKA: Patients with postoperative incision are Ⅰ healing,no complications related to the operation.Patients in both groups were followed up for 10-12 months,with an average of 11 months.HSS score and AKS score in the two groups at 6 months after surgery were both improved compared with those before surgery(P<0.05),but there was no significant difference between the two groups.Postoperative X-ray showed that the prosthesis was in good position,and no prosthesis loosening or sinking occurred during the follow-up.HKA,PCA and PFA were significantly improved in the two groups at 10 months after surgery compared with those before surgery(P<0.05).There was no significant difference in HKA between the two groups.PCA and PFA in the guide group were significantly lower than those in the control group(P<0.05).3.Gait analysis:(1)Comparison of 3DP assisted TKA patients and healthy volunteers: At 6 months after the operation,the velocity,cadence,stride length,maximum knee flexion angle(stance),minimum knee flexion angle(stance),maximum knee flexion angle(swing)of 3DP guide assisted TKA patients were all lower than that of healthy volunteers.And the mean hip rotation angle(stance),mean ankle rotation angle(stance)were higher than that of the healthy volunteers(P<0.05).(2)The comparison of patients with 3DP guide assisted TKA and those with traditional TKA: In terms of kinematic parameters,the max flexion angle at stance phase of the 3DP group was higher than that of the other two groups(P<0.05),there was no statistically significant difference in other parameters.In terms of kinetic and spatiotemporal parameters,there was no significant difference among the three groups.Conclusion: 1.TKA assisted by 3DP guide is relatively minimally invasive,which can accurately assist femoral intramedullary guide,correct the deformity of the knee joint and reduce the symptoms of pain,but the operation time is slightly prolonged;2.3DP guide assisted TKA achieves the goal of accurate femoral rotation alignment,providing anatomical basis for obtaining a good patella tracking;3.Compared with traditional TKA,the early gait pattern of patients after 3DP guide-assisted TKA mainly showed an increase in the max flexion angle at stance phase.The increase in the max flexion angle at stance phase further confirms the advantage of the 3DP guide in improving the patellar tracking;4.The early gait parameters of patients after TKA assisted by 3DP guide have not reached the level of healthy people,so further functional exercise is required. |
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