title: What Are the Risk Factors for Infection in Hemiarthroplasties and Total Hip Arthroplasties? A Comparison between Robotic-assisted and Manual Implantation of Cementless Total Hip Arthroplasty Primary and Revision Total Hip Replacement Using the Robodoc® System [Clinical outcome following robotic assisted versus conventional total hip arthroplasty: a controlled and prospective study of seventy-one patients]. Effect of robotic milling on periprosthetic bone remodeling. Hands-on robotic unicompartmental knee replacement: a prospective, randomised controlled study of the acrobot system. Acetabular Polyethylene Wear and Acetabular Inclination and Femoral Offset Comparison of Robotic-assisted and Conventional Acetabular Cup Placement in THA: A Matched-pair Controlled Study Comparison of robotic-assisted and manual implantation of a primary total hip replacement. A prospective study. Technique and first clinical results of robot-assisted total knee replacement. Robot-assisted primary cementless total hip arthroplasty with a short femoral stem: a prospective randomized short-term outcome study
abstract: Background Late infection is the second most frequent early complication after total hip arthroplasty ( THA ) and the most frequent after hemiarthroplasty . Known risk factors for infection after THA include posttraumatic osteoarthritis , previous surgery , chronic liver disease , corticoid therapy , and excessive surgical time . However , risk factors for hemiarthroplasty are not clearly established . Questions / purpose sWe therefore determined the preoperative and intraoperative risk factors for late infection ( more than 3 months after surgery ) in patients with hemiarthroplasties and THAs . Methods We retrospectively compared 47 patients with a hip arthroplasty ( 23 hemiarthroplasties , 24 total hip arthroplasties ) and late infection with 200 r and omly-selected patients with primary arthroplasty ( 100 hemiarthroplasties , 100 total hip arthroplasties ) during the same time period of time without any infection during followup . Potential risk factors were identified from medical records . Minimum followup was 12 months ( mean , 27 months ; range , 12–112 months ) for the study group and 18 months ( mean , 84 months ; range , 18–144 months ) for the control group . Results The following factors were more frequent in late infected hemiarthroplasties : female gender ; previous surgery ; obesity ( body mass index greater than 30 kg/m2 ) ; glucocorticoid and immunosuppressant treatments ; prolonged surgical time ; inadequate antibiotic prophylaxis ; prolonged wound drainage ; hematoma ; dislocation ; and cutaneous , urinary , and /or abdominal infections . The following were more frequent in infected total hip arthroplasties : posttraumatic osteoarthritis ; previous surgery ; glucocorticoids ; chronic liver disease ; alcohol and intravenous drug abuse ; prolonged surgical time ; prolonged wound drainage ; dislocation ; subsequent surgery ; and cutaneous , urinary , respiratory and abdominal infections . Diabetes did not appear to be a risk factor . Conclusions Our data suggest there are specific risk factors for infection in hemiarthroplasties . The major risk factors for late infection in hip arthroplasty must be recognized so they can be minimized or controlled if not possible to employ prophylactic measures .Level of Evidence Level III , prognostic study . See Guidelines for Authors for a complete description of levels of evidence Background The benefits of robotic techniques for implanting femoral components during THA are still controversial . Questions / Purpose sThe purpose of this study was to prospect ively compare the results and complications of robotic-assisted and h and -rasping stem implantation techniques . Method The minimum followup was 5 years ( mean , 67 months ; range , 60–85 months ) . One hundred forty-six primary THAs on 130 patients were included in this study .  Robot-assisted primary THA was performed on 75 hips and a h and -rasping technique was used on 71 hips . Results At 2 and 3 years postoperatively , the Japanese Orthopaedic Association ( JOA ) clinical score was slightly better in the robotic-assisted group . At 5 years followup , however , the differences were not significant . Postoperative limb lengths of the robotic-milling group had significantly less variance than the h and -rasping group . At 2 years postoperatively , there was significantly more stress shielding of the proximal femur in the h and -rasping group ; this difference was more significant 5 years postoperatively . Conclusions Substantially more precise implant positioning seems to have led to less variance in limb-length ine quality and less stress shielding of the proximal femur 5 years postoperatively . Level of Evidence Level II , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence The ROBODOC ® system was design ed to address potential human errors in performing cementless total hip replacement . The system consists of a preoperative planning computer workstation ( called ORTHODOC ) and a five-axis robotic arm with a high speed milling device as an end effector . The combined experience of the United States Food and Drug Administration multicenter trial and the German postmarket use of the system are reported . The United States study is controlled and r and omized with 136 hip replacements performed at three centers ( 65 ROBODOC ® and 62 control ) . Followup was 1 year on 127 hip replacements and 2 years on 93 hip replacements . No differences were found in the Harris hip scores or the Short Form Health Survey outcomes question naire . Length of stay also was not different , but the surgical time and blood loss were greater in the ROBODOC ® group . This was attributed to a learning curve at each center . Radiographs were evaluated by an independent bone radiologist and showed statistically better fit and positioning of the femoral component in the ROBODOC ® group . Complications were not different , except for three cases of intraoperative femoral fracture in the control group and none in the ROBODOC ® group . The German study reports on 858 patients , 42 with bilateral hip replacements and this includes 30 revision cases for a total of 900 hip replacements .  The Harris hip score rose from 43.7 to 91.5 . In these cases the surgical time declined quickly from 240 minutes for the first case to 90 minutes . No intraoperative femoral fractures occurred in 900 cases . Other complications were comparable with total hip replacements performed using conventional techniques . The ROBODOC ® system is thought to be safe and effective in producing radiographically superior implant fit and positioning while eliminating femoral fractures AIM Robotic assisted total hip arthroplasty  remains controversial , since wider exposure of the proximal femur and placement of the leg in maximal hip adduction and external rotation using a rigid leg-holder apparatus may impair significantly the hip abductors . Consequently , it is the purpose of this study to analyse and report both clinical outcome and hip abductor function following robotic assisted versus conventional total hip arthroplasty . MATERIAL AND METHODS 36 robotic-assisted ( CASPAR , Orto-Maquet , Rastatt , Germany ) and 35 conventional cementless total hip arthroplasties  were followed on average for 18 months regarding incidence of complications , Harris hip score , the scoring system according to Merle d'Aubigné and Postel , hip abductor function ( using a spring-balance ) , and incidence of Trendelenburg 's sign ( according to the Kuhfuss-classification ) . Statistical analysis was performed in case of continuous data using the t test and the Mann-Whitney test , respectively , and in case of categorical data using Fisher 's exact test and the chi-squared test , respectively . The level of significance was set as p < 0.05 . RESULTS Average duration of surgery ( CASPAR : 100.6 min ; conventional : 51.5 min ; p < 0.0001 ) as well as average loss of haemoglobin ( CASPAR : 4.5 mg/dL ; conventional : 3.3 mg/dL ; p = 0.0002 ) differed significantly , whereas the incidence of complications ( CASPAR : two dislocations , one sciatic paresis , one deep infection ; conventional : one dislocation , two fissures ) , revision rate ( CASPAR : 5.6 % ; conventional : 2.9 % ) , and incidence of heterotopic ossifications ( CASPAR : 30.6 % ; conventional : 17.1 % ) was comparable following both procedures ( p > 0.05 ) . Improvement of the Harris hip score also was comparable in both groups ( CASPAR : 40.9 to 86.1 points ; conventional : 39.5 to 88.0 points ; p = 0.21 ) , whereas improvement of the score according to Merle d'Aubigné and Postel was significantly greater following the manual procedure ( CASPAR : 10.1 to 16.0 points ; conventional : 8.3 to 16.6 points ; p < 0.0001 ) . Differences between the two groups were also significant regarding hip abductor function ( CASPAR : 76.1 % ; conventional : 93.8 % of the contralateral hip ; p < 0.0001 ) and incidence of Trendelenburg 's sign ( CASPAR : 61.1 % ; conventional : 25.7 % ; p = 0.0014 ) . CONCLUSION The significant functional impairment following robotic assisted THA should be taken critically into consideration prior to initiating such procedure The ROBODOC system has provided better fit and fill of the stem and less destruction of the bony architecture than with manual surgery . These benefits might affect femoral periprosthetic bone remodeling . We evaluated the effects of robotic milling in cementless total hip arthroplasty ( THA ) in a longitudinal 24-month follow-up study using dual energy X-ray absorptiometry ( DEXA ) and plain radiographs of 29 patients ( 31 hips ) after ROBODOC THA and 24 patients ( 27 hips ) after manual THA with the same stem design . To minimize the influence of other factors on bone remodeling , only female osteoarthritis patients , who had no drugs that might affect bone metabolism were enrolled . Significantly less bone loss occurred at the proximal periprosthetic areas in the ROBODOC group . In zone 1 , the decrease was 15.5 versus 29.9 % using conventional rasping ; in zone 7 , the loss was 17.0 % with ROBODOC compared to 30.5 % with conventional rasping ( p < 0.05 ) . On radiographs , endosteal spot welds in the proximal medial portion were more pronounced in the ROBODOC group ( 48 vs. 11 % in the conventional group , p < 0.05 ) . Our results suggest that robotic milling is effective in facilitating proximal load transfer around the femoral component and minimizing bone loss after cementless THA We performed a prospect i ve , r and omised controlled trial of unicompartmental knee arthroplasty comparing the performance of the Acrobot system with conventional surgery . A total of 27 patients ( 28 knees ) awaiting unicompartmental knee arthroplasty were r and omly allocated to have the operation performed conventionally or with the assistance of the Acrobot . The primary outcome measurement was the angle of tibiofemoral alignment in the coronal plane , measured by CT . Other secondary parameters were evaluated and are reported . All of the Acrobot group had tibiofemoral alignment in the coronal plane within 2 degrees of the planned position , while only 40 % of the conventional group achieved this level of accuracy . While the operations took longer , no adverse effects were noted , and there was a trend towards improvement in performance with increasing accuracy based on the Western Ontario and McMaster Universities Osteoarthritis Index and American Knee Society scores at six weeks and three months . The Acrobot device allows the surgeon to reproduce a pre-operative plan more reliably than is possible using conventional techniques which may have clinical advantages Abstract Restoration of femoral offset and acetabular inclination may have an effect on polyethylene ( PE ) wear in THA . We therefore assessed the effect of femoral offset and acetabular inclination ( angle ) on acetabular conventional ( not highly cross-linked ) PE wear in uncemented THA . We prospect ively followed 43 uncemented THAs for a minimum of 49 months ( mean , 64 months ; range , 49–88 months ) .  Radiographs were assessed for femoral offset , acetabular inclination , and  conventional PE wear . The mean ( ± st and ard deviation ) linear wear rate in all THAs was 0.14 mm/year ( ± 0.01 mm/year ) and the mean volumetric wear rate was 53.1 mm3/year ( ± 5.5 mm3/year ) . In THAs with an acetabular angle less than 45 ° , the mean wear was 0.12 mm/year ( ± 0.01 mm/year ) compared with 0.18 mm/year ( ± 0.02 mm/year ) in those with a reconstructed acetabular angle greater than 45 ° . Reproduction of a reconstructed femoral offset to within 5 mm of the native femoral offset was associated with a reduction in conventional PE wear ( 0.12 mm/year versus 0.16 mm/year ) . Careful placement of the acetabular component to ensure an acetabular angle less than 45 ° in the reconstructed hip allows for reduced conventional PE wear . Level of Evidence : Level II , prospect i ve study . See Guidelines for Authors for a complete description of levels of evidence Background Improper acetabular component orientation in THA has been associated with increased dislocation rates , component impingement , bearing surface wear , and a greater likelihood of revision . Therefore , any reasonable steps to improve acetabular component orientation should be considered and explored . Questions / purpose sWe therefore sought to compare THA with a robotic-assisted posterior approach with manual alignment techniques through a posterior approach , using a matched-pair controlled study design , to assess whether the use of the robot made it more likely for the acetabular cup to be positioned in the safe zones described by Lewinnek et al. and Callanan et al. Methods Between September 2008 and September 2012 , 160 THAs were performed by the senior surgeon . Sixty-two patients ( 38.8 % ) underwent THA using a conventional posterior approach , 69 ( 43.1 % ) underwent robotic-assisted THA using the posterior approach , and 29 ( 18.1 % ) underwent radiographic-guided anterior-approach THAs .  From September 2008 to June 2011 , all patients were offered anterior or posterior approaches regardless of BMI and anatomy . Since introduction of the robot in June 2011 , all THAs were performed using the robotic technique through the posterior approach , unless a patient specifically requested otherwise . The radiographic cup positioning of the robotic-assisted THAs was compared with a matched-pair control group of conventional THAs performed by the same surgeon through the same posterior approach . The safe zone ( inclination , 30 ° –50 ° ; anteversion , 5 ° –25 ° ) described by Lewinnek et al. and the modified safe zone ( inclination , 30 ° –45 ° ; anteversion , 5 ° –25 ° ) of Callanan et al. were used for cup placement assessment . Matching criteria were gender , age ± 5 years , and ( BMI ) ± 7 units . After exclusions , a total of 50 THAs were included in each group . Strong interobserver and intraobserver correlations were found for all radiographic measurements ( r > 0.82 ; p < 0.001 ) . Results One hundred percent ( 50/50 ) of the robotic-assisted THAs were within the safe zone described by Lewinnek et al. compared with 80 % ( 40/50 ) of the conventional THAs ( p = 0.001 ) . Ninety-two percent ( 46/50 ) of robotic-assisted THAs were within the modified safe zone described by Callanan et al. compared with 62 % ( 31/50 ) of conventional THAs p ( p = 0.001 ) . The odds ratios for an implanted cup out of the safe zones of Lewinnek et al. and Callanan et al. were zero and 0.142 , respectively ( 95 % CI , 0.044 , 0.457 ) . Conclusions Use of the robot allowed for improvement in placement of the cup in both safe zones , an important parameter that plays a significant role in long-term success of THA . However , whether the radiographic improvements we observed will translate into clinical benefits for patients —such as reductions in component impingement , acetabular wear , and prosthetic dislocations , or in terms of improved longevity — remains unproven . Level of Evidence Level III , therapeutic study . See the Instructions for Authors for a complete description of levels of evidence BACKGROUND Robotic-assisted total hip replacement  has become a common method of implantation , especially in Europe . It frequently has been postulated that robotic reaming would result in an improved clinical outcome due to the better fit of the prosthesis , but that has never been demonstrated in a prospect i ve study , to our knowledge . The purpose of this study was to compare robotic-assisted implantation of a total hip replacement with conventional manual implantation . METHODS One hundred and fifty-four patients scheduled for total hip replacement were r and omly assigned to undergo either conventional manual implantation of an S-ROM prosthesis ( eighty patients ) or robotic-assisted implantation of such a prosthesis ( seventy-four patients ) . The five-axis ROBODOC was used for the robotic-assisted procedures . Preoperatively as well as at three , six , twelve , and twenty-four months after surgery , the scores according to the Harris and Merle d'Aubigné systems and the Mayo clinical score were determined . Radiographs made at these intervals were analyzed for evidence of loosening , prosthetic alignment , and heterotopic ossification . RESULTS Thirteen ( 18 % ) of the seventy-four attempted robotic implantations had to be converted to manual implantations as a result of failure of the system . The duration of the robotic procedures  was longer than that of the manual procedures ( mean and st and ard deviation,107.1 + /- 29.1 compared with 82.4 + /- 23.4 minutes , p < 0.001 ) . Limb-length e quality ( mean discrepancy , 0.18 + /- 0.30 compared with 0.96 + /- 0.93 cm , p < 0.001 ) and varus-valgus orientation of the stem ( mean angle between the femur and the shaft of the prosthesis , 0.34 degrees + /- 0.67 degrees compared with 0.84 degrees + /- 1.23 degrees , p < 0.001 ) were better after the robotic procedures . At six months , slightly more heterotopic ossification was seen in the group treated with robotic implantation . The group treated with robotic implantation had a better Mayo clinical score at six and twelve months and a better Harris score at twelve months ; however , by twenty-four months , no difference was found between the groups with regard to any of the three scores . Dislocation was more frequent in the group treated with robotic implantation : it occurred in eleven of the sixty-one patients in that group compared with three of eighty in the other group ( p < 0.001 ) . Recurrent dislocation and pronounced limping were indications for revision surgery in eight of the sixty-one patients treated with robotic implantation compared with none of the seventy-eight ( excluding two with revision for infection ) treated with manual insertion ( p < 0.001 ) . Rupture of the gluteus medius tendon was observed during all of the revision operations . CONCLUSIONS The robotic-assisted technology had advantages in terms of preoperative planning and the accuracy of the intraoperative procedure . Disadvantages were the high revision rate ; the amount of muscle damage , which we believe was responsible for the higher dislocation rate ; and the longer duration of surgery . This technology must be further developed before its widespread usage can be justified Total knee replacement ( TKR ) is a common procedure for treatment of severe gonarthrosis  , but the outcome may be unsatisfactory due to primary malalignment of the prosthetic components . In order to improve precision and accuracy of this surgical procedure , a commercial robotic surgical system ( CASPAR ) has been adapted to assist the surgeon in the preoperative planning and intraoperative execution of TKR . So far , 70 patients with idiopathic gonarthrosis were successfully treated with a robot-assisted technique in our institution . No major adverse events related to the use of the robotic system have been observed . The mean difference between preoperatively planned and postoperatively achieved tibiofemoral alignment was 0.8 degrees ( 0 - 4.1 degrees ) in the robotic group vs. 2.6 degrees ( 0 - 7 degrees ) in a manually operated historical control group of 50 patients . A clear advantage of robot-assisted TKR seems to be the ability to execute a highly precise preoperative plan based on computed tomography ( CT ) scans . Due to better alignment of the prosthetic components and improved bone-implant fit , implant loosening is anticipated to be diminished which may be most evident in non-cemented prostheses . Current disadvantages such as the need for placement of fiducial markers , increased operating times and higher overall costs have to be resolved in the future Abstract Background : Recently , two topical issues in total hip arthroplasty ( THA ) have been robot-assisted surgery and use of a short stem . The purpose of this study was to evaluate the effects of robotic milling on the accuracy of short femoral stem positioning and on the short-term clinical outcome in THA using a prospect i ve , r and omized design . Methods : We r and omized 54 patients into two groups , either robotic milling group or manual rasping group .  The patients were assessed clinical ly and radiographically at 8 weeks , 5 months , 12 months , and 24 months . Results : Robotic milling group had a significantly longer operation time , requiring on average 8.9 min for registration and 11.2 min for milling . On the other h and , robotic milling group showed superior results in terms of stem alignment and leg length e quality . Two intraoperative femoral fractures occurred only in manual rasping group . Harris hip scores and WOMAC scores at 24 months postoperatively were similar in both groups . No complications including stem loosening , infection , nerve palsy , or dislocation were encountered in either group during the follow-up period . Conclusions : The present study suggested that robot-assisted short stem THA could increase the accuracy of stem alignment , improve leg length e quality , and help reduce the risk of intraoperative femoral fracture as compared with manual rasping . However , the clinical outcome scores did not differ between the two groups at the time of short-term follow-up . Long-term follow-up is needed to determine whether there will be a long-term clinical relevance of robot-assisted implantation of short femoral stems in THA
target: Conclusion The results of this meta- analysis suggest that robotic-assisted THA has certain advantages over conventional THA , including the results of component positioning and rates of intraoperative complications .
background: Background Robotic-assisted total hip arthroplasty ( THA ) allows for accurate preoperative planning and component positioning , potentially enhancing implant survival and long-term outcomes .
  The relative efficacy and safety of robotic-assisted and conventional THA , however , are unclear .
  This systematic review and meta- analysis compared the safety and efficacy of robotic-assisted and conventional THA .