| BackgroundOsteoarthritis(OA)is an increasingly serious health problem in health care worldwide.At present,about 1%of the world’s adults suffer from advanced ankle OA Ankle OA is characterized by persistent aggravation of joint pain,swelling,decreased activity and even disappearance,which seriously affects the quality of life of patients Now it has become the most common osteoarthritis disease after knee arthritis and hip arthritis,which has been paid more and more attention by cliniciansAnkle arthrodesis(AA)and total ankle replacement(TAR)are the main methods for the treatment of advanced ankle OA.However,both are sacrificial joint surgery rather than preserving joint surgery.With benefit of reliable relieved ankle pain,AA will simultaneously sacrifice the mobility of ankle joint,which often leads to abnormal gait and degeneration of adjacent foot joint after operation.Ankle replacement,with retained postoperative mobility of joint,is more and more popular in recent years.However,its application in China is limited because of the mismatch of prosthesis and Chinese bone shape,more relative contraindications and high incidence of complications.Therefore,it is of great clinical significance for our Chinese to take effective measures to delay or terminate the progression of moderate ankle OA.Supramalleolar osteotomy(SMO)plays an important role in the current joint-preserving surgery.It leads to a delayed or even terminated ankle degeneration by corrected alignment of tibia and talus and improved intraarticular load distribution.Accurate bone-cutting at the centers of rotation of angulation(CORA)is the key to success in SMO and it has been followed with interest for many years.In traditional osteotomy,the freehand guidewire inserting technique tends to cause inaccurate guidewire position especially in surgery for complex ankle arthritis with intra-articular deformity.The repeated adjustment of guidewire is time-consuming and leads to increased risk of anesthesia and joint injury,and decreased efficacy is ineluctable if the deviation of the guidewire is particular large.With the development of minimally invasive surgery technology and precision medicine,orthopaedic robotic surgery has gradually begun to rise.TianJi Robot has the characters of intelligence,minimally invasive and high accuracy,and has been widely used in sacroiliac fixation and spinal pedicle screw implantation.However,there is no report of robot assisted foot and ankle surgery in China except for one study about robot-assisted tibiotalocalcaneal arthrodesis.Worldwide,no report about robot-assisted osteotomy for ankle osteoarthritis has been reported.The particular advantage of robot-assisted surgery is prominent accuracy with a error less than 1mm.However,it’s difficult to keep absolute interoperative immobility of the foot with the instruments available now,which leads to decreased advantage of the robot due to excessive deplacement of the foot.Moreover,in robot-assisted surgery,the patient tracer ususlly is immobilized with a screw insered into adjacent bone,which leads to iatrogenic injury.As a "National Orthopaedic Surgery Robot Application Center" awarded by the National Ministry of Industry and Information Technology and the National Health and Health Commission,our hospital has been undertaking the sub-project of the national key research and development program "Development of Multi-indications Orthopedic Surgical Robot Products" in the recent years.We designed a clinically meaningful device,the "Foot Fixator for Orthopedic Surgery Robots"(FFOSR),and porformed many robot-assisted foot and ankle surgeries as well as robot-assisted SMO.Based on the FFOSR,the current study explored the operation process of robot-assisted osteotomy for moderate and severe ankle osteoarthritis.Objective:1.To explore the operation process of robot-assisted osteotomy for moderate and severe ankle osteoarthritis;2.To observe the effect of robot-assisted osteotomy technique on surgical process as well as radiographic and clinical results of for ankle arthritis through clinical studiesMaterials and Methods:The first part,to explore the surgical process of robot assisted osteotomy in the treatment of moderate and severe ankle osteoarthritis.Basing on the "Foot Fixator for Orthopedic Surgery Robots"(FFOSR),the process includs:1.Ankle debridement;2.Immobilization of foot and patient tracer with the FFOSR without iatrogenic injury;3.Intraoperative imaging examination for Robotic Surgery;4 Imaging information transmitted to robot workstation to generate planning view;5.To design guidewires on robotic workstation;6.To simulate the running trajectory of robotic arm to insert guidewires;7.Bone-cutting,adjustment of fragmcnt of distal tibia and imaging confinnation;8.Autogenous bone graft and distal tibia fixation;9 Other auxiliary procedures.The second part,clinical study.General information:From September 2017 to September 2018,we performed 20 consecutive SMO in 20 patients with moderate or severe ankle OA.According to the time of admission,the patients were divided into a robot-assisted osteotomy(RAO)group and a conventional osteotomy(CO)group,both with 10 cases.According to Tanaka ankle osteoarthritis staging,there were 1 case in stage 2,7 cases in stage 3 a and 2 cases in stage 3b in the RAO group,and 2 patients in stage 2,6 patients in stage 3a and 2 patients in stage 3b in the CO group.Two patients in both group presented with significant intra-articular deformity and the SMO was performed combined with an intra-articular osteotomy(plafond osteotomy)Operative Technique:In the RAO group,the robot-assisted osteotomy was performed according to the process introduced above,while in the CO group,the other procedures were the same as those in the RAO group except that the osteotomy guide wires were inserted by hand.Statistical indicators:(1)general results;(2)results of guidewire insertion,including the number of times of the guidewire insertion,fluoroscopy frequency,the time of guidewire insertion(min)and the final deviation(mm)of each guidewire;(3)radiographic indicators including:the medial distal tibial angle(MDTA)and anterior distal tibial angle(ADTA)before and after surgery;(4)American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale(AOFAS)score and visual analogue scale(VAS)score before and one year after surgery.Results:1.general result:All 20 patients were followed up 1 year after surgery.Uneventful bone union was achieved in all patients,the average time for union was 3.9±0.99 months(3-6 months)和 4.0±1.08 months(3-6 months.Two patients in the RAO group got lower extremity intermuscular vein thrombosis were cured by drug therapy.One patient in the CO group got slight superficial soft tissue infection was cured by dress changing.Internal hardware was removed in 2 cases in each group due to soft tissue irritation,and no further joint fusion or replacement operation was performed in all cases.2.Results of bone-cut-ting guidewire insertion:a total of 24 guidewires were inserted in each group eventually:2 guidewires for supermalleolar osteotomy in each patient,and another 2 guidewires for intraarticular osteotomy in the patients with intra-articular deformity.The number of times of the guidewire insertion:In the RAO group,the guidewires(including extra-articular and intra-articular)were placed in the predetermined position at one time under the guidance of the robot;the average number of guidewire insertion per case was 2.40+0.84.In the CO group,the average number of guidewire insertion per case was 5.40 2.01.Fluoroscopy frequency of C-arm or 3D C-arm:The fluoroscopy frequency was 3.80±0.42 in the RAO group and 10.3±4.83 in the control group respectively.The time of guidewire insertion per case:the time of guidewire insertion per case was 3.4±1.51 minutes in the RAO group and 11.6±3.62 minutes in the control group respectively.The final deviation of each guidewire:in the RAO group and the CO group,the mean deviation of each guidewire was 1.07±0.91mm and 5.40±2.27mm respectively.There were signifi cant differences in number of times of the guidewire insertion(p=0.0021),fluoroscopy frequency(p=0.0187),time of guidewire insertion(p=0.0003),and final deviation of each guidewire(p=0.0002),and RAO group was significantly better than CO group.3.Changes of radiographic indicators:In the RAO group and in the CO group,MDTA was improved from 81.0°±2.16°before sugery to 90.6°±1.08°one year after surgery and from 81.6°±1.51°to 90.7°±3.2 7°.respectively,and there was significant statistical difference(both p=0.000)in both groups.However,there was no significant difference in MDTA one year after surgery between the two groups(p=0.4804).In the RAO group and in the CO group,ADTA was improved from 82.01°±1.15°before sugery to 83.9°±1.10°one year after surgery and from 81.6°±1.35° to 83.3°±1.16°,respectively,and there was significant statistical difference(p=0.0014 and p=0.0073)in both groups.However,there was no significant difference in ADTA one year after surgery between the two groups(p=0.0.2507).4.Clinical function score and pain score:In the RAO group and in the CO group.AOFAS ankle-hindfoot score increased from 45.7±9.80 before surgery to 85.4±5.42 one year after surgery and from 47.3±7.48 to 80.2±2.86,respectively,and there was significant statistical difference(both p=0.0000)in the both groups,and AOFAS score one year after surgery of the RAO group was better than that of the CO group(p=0.0181).VAS score in the RAO group improved from 5.00±2.00 before surgery to 1.40±0.70 one year after surgery and from 5.10±1.29 to 1.50±0.53 in the CO group,there was significant statistical difference(p=0.0000)in both groups.However,there was no significant difference in VAS score one year after surgery between the two groups(p=0.8312).Conclusions:1.The robot-assisted osteotomy based on "Foot Fixator for Orthopedic Surgery Robots" can be successfully applied for moderate and severe ankle osteoarthritis,and will continue to improve with the improvement of relevant equipment.2.Compared with conventional osteotomy,the robot-assisted osteotomy has the potential of significant improvements in osteotomy process especially in the treatment of complex cases with severe intra-articular deformity,with faster guidewire insertion,less deviation and fluoroscopy frequency.3.Osteotomy can restore the alignment of the distal tibia and improve the radiographic indicators and function.It is an effective method for the treatment of osteoarthritis.4.The cases in this study show that the functional score after robot-assisted supramalleolar osteotomy is superior to that of traditional osteotomy,and more cases need to be accumulated in the future to increase credibility. |
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