Clinical Application And Early Curative Effect Of Robotic Assisted Total Hip Arthroplasty

Background:Total hip arthroplasty(THA)is an effective surgical procedure for end-stage hip disease.In recent years,with the increasingly mature technology of hip arthroplasty and the development of aging population,the number of hip arthroplasty operations has increased significantly and entered the stage of rapid growth.The poor placement of prostheses is closely related to the occurrence of multiple postoperative complications and the survival rate of prostheses.However,there is a high incidence of poor placement of prostheses in traditional THA surgery.In order to improve the precision of placement of Robotic hip arthroplasty(THA),robotic assisted THA(RATHA)was created.At present,several surgical robots have been applied in the field of hip joint arthroplasty internationally,and studies have proved the advantages of RATHA in prosthesis positioning,restoring normal physiological structure and other aspects,but at present,there is insufficient research and literature to support the improvement of postoperative clinical effects of RATHA.There are many approaches for hip joint surgery,and different approaches have their own advantages and disadvantages as well as indications.However,RATHA is often based on navigation technology and has high requirements for patients’ position and exposure to surgical field.Currently,most studies on RATHA use posterolateral or anterolateral approaches,while there are insufficient studies on the surgical effects of other approaches.In addition,most of the robots currently applied in THA only participate or directly participate in the operation on the acetabular side,but cannot participate in the operation on the femur side.Although some robots can assist the operators to determine the osteotomy line of the femoral neck,or verify the lower limb length discrepancy(LLD)and the position of the prosthesis after implant,the operation on the femur side still requires the operators to use conventional surgical methods.This means that the problem of inaccurate positioning of femur prosthesis during routine surgical procedures cannot be avoided.The studies on the location of the prosthesis in robot-assisted THA mostly focus on the acetabular prosthesis,while the studies on the location of the femur prosthesis are obviously insufficient.The position of femoral prosthesis is also closely related to the occurrence of complications after THA and the survival rate of prosthesis.Longwell Hip Surgery Robot(Shanghai Longwell Medical Technology Co.,LTD.,model specification: TRex-RS,system software version: HIP1.0)" made in China can cover the whole process of hip arthroplasty and directly participate in the operation of acetabular side and femur side at the same time.The study of its surgical effect can evaluate its application value and provide reference for the development of hip arthroplasty robot,which has important clinical and scientific significance.Purpose:The aim of this study was to evaluate the accuracy,postoperative clinical outcomes,and complication characteristics of RATHA surgical prosthesis implantation via direct lateral approach by analyzing data from patients’ medical records,postoperative imaging data,and patient follow-up data.The study includes:(1)analysis of RATHA surgical outcomes,i.e.,comparison of the postoperative prosthesis position and postoperative functional scores after RATHA and conventional THA;(2)analysis of the accuracy of RATHA prosthesis position,i.e.,comparison of the postoperative prosthesis position with the preoperative planning;(3)Imaging analysis of "planned-actual" prosthesis discrepancy,i.e.,imaging analysis of cases where the RATHA intraoperative prosthesis type selection does not match the preoperative planning.Methods:The preoperative and postoperative imaging data,intraoperative records and follow-up data of patients receiving total hip replacement in the Affiliated Hospital of Qingdao University from December 2020 to October 2022 were retrospectively analyzed,and were divided into 3groups according to the surgical method: Patients receiving THA assisted by LONGWELL robot were recorded as "LR group";Patients who underwent THA assisted by "MAKO robot" were recorded as the "MR Group",and patients who underwent THA by conventional operation were recorded as the "control group".Methods:(1)Analysis of the effect of RATHA surgery: The three groups of patients in the LR,MR and control groups were measured for each postoperative imaging data,including the acetabular anteversion and abduction angles,femoral neck anteversion angle,femoral stem coronal plane angulation(CA),LLD and canal fill ratio(CFR)of femoral stem,etc.The differences between the three groups were statistically analyzed to evaluate the two robots relative to the traditional surgical approach in improving the early treatment effect in surgery effect.(2)RATHA prosthesis position accuracy analysis: The data of postoperative acetabular anteversion and abduction angle,LLD,eccentric distance,and femoral anteversion angle were measured in the three groups and compared with the corresponding data of preoperative planning,so as to evaluate the accuracy of the two surgical robots in performing preoperative planning.(3)Imaging analysis of the discrepancy between the "planned and actual" prosthesis models: The MR group was divided into four subgroups,including the matched group,the enlarged group,the reduced group,and the deviated group,according to the size of the discrepancy between the models,and the differences in the imaging data between the subgroups were measured and analyzed to find the difference between the intraoperative applied prosthesis and the preoperative planned model.We measured and analyzed the differences in imaging data between the subgroups to find the reasons for the discrepancy between the applied prosthesis and the preoperative planning.Result:(1)The Longwell robot implanted 94.3%(33 cases)of the acetabular cup within the safe range of 5° to 25° of anteversion,which was significantly better than the conventional THA(74.4%,P=0.013);if both anteversion and abduction angles were considered,the Longwell robot implanted 91.4% of the cup within the Lewinnek safe zone,which was also significantly better than the conventional THA(65.6%,P=0.004).The Mako robot implanted a significantly higher percentage of cup into the safe range than the control group,regardless of whether the Lewinnek or the Callanan safe zone was considered,nor whether the anteversion or abduction angle,or both anteversion and abduction angles were considered.The Longwell robot was able to implant the femoral stem in a neutral position in all 35 cases(100%),significantly higher than in the control(83.3%,P=0.010)and MR groups(84.8%,P=0.023).The postoperative LLD in the LR group was 3.77±8.31 mm,which was significantly smaller than that in the control group(8.99±10.20 mm,P=0.008)and MR group(8.56±10.20 mm,P=0.029).The Longwell robot did not exhibit a significant advantage in terms of femoral CFR.The Harris score and forgotten joint score at 1 month,3 months and 6months postoperatively obtained good results in all three groups,and there was no obvious difference between the 3groups.(2)Both robots obtained excellent accuracy and precision in completing the preoperative planning of center of rotation(COR)position,LLD and acetabular orientation.In addition,the Longwell robot also showed good accuracy and precision in completing preoperative planning for femoral offset(FO),femoral anteversion and CA.Postoperative measurements values of FO(R=0.960),COR position in horizontal(R=0.868)and vertical(R=0.987)directions in the LR group were highly correlated with preoperative planning,and LLD(R=0.766)and femoral anteversion angle(R=0.775)were moderately correlated with preoperative planning.The postoperative measurements values of COR in the horizontal(R=0.923)and vertical(R=0.976)directions in the MR group were highly correlated with preoperative planning,and the LLD(R=0.72)were moderately correlated.(3)The absolute CA in the reduced group was 2.55°(1.45° to 3.125°),which was significantly greater than that in the matched group(1.25°(0.375° to 2.4°),P=0.047)and the enlarged group(0.4°(0.075° to 0.65°),P=0.004).There were no significant differences between the three groups in terms of CFR in all planes and CA.The data of one patient in the deviated group were significantly deviated from normal values.Conclusion:RATHA via the direct lateral approach could complete preoperative planning precisely and accurately.Compared to conventional THA,the surgical robots can implant the prosthesis in the proper position with greater precision.If the intraoperative prosthesis selected is smaller than the preoperatively planned size,it should be noted that this may be caused by a large coronal plane angulation of the femoral stem or a failure to achieve a good CFR.