title: Influence of cement viscosity and cement mantle thickness on migration of the Exeter total hip prosthesis. Immediate weight bearing after uncemented total hip arthroplasty with an anteverted stem: A prospective randomized comparison using radiostereometry The ABG hydroxyapatite-coated hip prosthesis: one hundred consecutive operations with average 6-year follow-up. Poor outcome of the PCA and Harris-Galante hip prostheses. Randomized study of 171 arthroplasties with 9-year follow-up. No surgical innovation without evaluation: the IDEAL recommendations Wagner resurfacing hip arthroplasty. The results of one hundred consecutive arthroplasties after eight to ten years. The results of primary Birmingham hip resurfacings at a mean of five years. An independent prospective review of the first 230 hips. Clinical and radiographic outcomes of total hip arthroplasty with insertion of an anatomically designed femoral component without cement for the treatment of primary osteoarthritis. A study with a minimum of six years of follow-up. 100 Cemented Versus 100 Noncemented Stems With Comparison of 25 Matched Pairs Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component. Seven-to-Ten-Year Results* [Long-term results with the Harris-Galante press-fit-cup]. Bioactive cement or ceramic/porous coating vs. conventional cement to obtain early stability of the acetabular cup. Randomised study of 96 hips followed with radiostereometry. Hydroxyapatite coated hip prosthesis followed up for 5 years Migration of press-fit cups fixed with poly-L-lactic acid or titanium screws: a randomized study using radiostereometry. Survival of Hip Replacements: A Comparison of a Randomized Trial and a Registry The John Charnley Award. Practice surveillance: a practical method to assess outcome and to perform clinical research. Primary total hip arthroplasty with a proximally porous-coated femoral stem. Cemented versus uncemented socket in hip arthroplasty. A radiostereometric study of 60 randomized hips followed for 2 years. No difference in migration or wear between cemented low-profile cups and standard cups : A randomized radiostereographic study of 53 patients over 3 years Ten-year survivorship of the Anatomique Benoist Girard I total hip arthroplasty. Second-Generation Cementless Total Hip Arthroplasty: Eight to Eleven-Year Results Introducing new technology: a stepwise algorithm. Does early micromotion of femoral stem prostheses matter? 4-7-year stereoradiographic follow-up of 84 cemented prostheses. Evaluation of Boneloc. Chemical and mechanical properties, and a randomized clinical study of 30 total hip arthroplasties. Migration of acetabular components, inserted with and without cement, in one-stage bilateral hip arthroplasty. A controlled, randomized study using roentgenstereophotogrammetric analysis. No Migration of Acetabular Cups after Prophylaxis for Heterotopic Ossification
abstract: The effect of bone cement viscosity and cement mantle thickness on the migration of the Exeter  total hip prosthesis  was studied in a prospect i ve , r and omized , double-blind clinical Roentgen Stereophotogrammetric Analysis study . Forty-one cemented total hip arthroplasty in 39 patients were included and r and omized into a low/medium Simplex P cement group and a high-viscosity Simplex AF cement group . At time of stem introduction , 5 minutes after mixing , the Simplex AF was more viscous than Simplex P. No statistical difference existed between the 2 cement groups , for neither translation nor rotation migration data . Subsidence of the stem at 2-year follow-up was 1.1 + /- 0.56 mm for Simplex AF cement and 1.5 + /- 1.00 mm for Simplex P cement . The mean rotation of the acetabular components about the sagittal axis was 1.7 degrees + /- 3.8 degrees in the Simplex AF group and 0.7 degrees + /- 2.1 degrees for the Simplex P group . No effect of cement mantle thickness on migration of neither the acetabular cups nor the femoral stems was found . Although there were no differences in migration data for the cups and the stems , 2 acetabular cups in the Simplex AF group ( almost 10 % ) were revised because of mechanical loosening . Because of these findings , we suggest caution before using this new high-viscosity bone cement for fixation of acetabular components Background In uncemented total hip arthroplasty with hydroxyapatite coating , early weight bearing is frequently practice d but there is still not much evidence to support this recommendation . Method In a prospect i ve r and omized study we evaluated the effect of partial and full weight bearing after  cementless total hip arthroplasty ( ABG ; Stryker-Howmedica ) using radiostereometric analysis ( RSA ) . Between February 1996 and February 2000 , 43 consecutive patients ( mean age 53 ( 41–63 ) years , 23 women ) with hip osteoarthrosis received an uncemented and hydroxyapatite-coated prosthesis with an anteverted stem . All patients were operated in a st and ardized way by three experienced surgeons and they were r and omized to partial ( P ) or full ( F ) weight bearing during the first 6 weeks after surgery . The patients in the partial weight bearing group were equipped with a pressuresensitive insole signaling when their load exceeded the prescribed weight limit . Results At 3-month follow-up , the mean proximal (+)/ distal ( - ) migration of the stem was -0.14 mm ( -1.93– 0.11 ) in group P and -0.31 mm ( -4.30–0.16 ) in group F ( p = 0.6 ) . At 1-year follow-up , the mean migration was –0.17 mm ( -2.18–0.21 ) and -0.28 mm ( -4.31–0.11 ) , respectively ( p = 0.9 ) . There was no significant difference in stem rotations either ( p < 0.2 ) . The cup translations , rotations , and femoral head penetration were similar in the two groups ( p < 0.1 ) . There were no re-operations during the first year . Interpretation We did not find any adverse effect of full weight bearing immediately after operation , which justifies use of this regimen after uncemented total hip arthroplasty of the ABG type One hundred consecutive ABG ( Anatomique Benoist Giraud , Howmedica ) hydroxyapatite-coated hip arthroplasties in 97 patients were evaluated prospect ively with a follow-up time of 4 to 10 years ( mean , 6 years ) . Clinical results were excellent with an improvement in the Merle d'Aubigne score from 9 preoperatively to 17.4 at 5 years . Thigh pain was persistent in only 3 % ; it was mild in nature and controlled with simple analgesics . Kaplan-Meyer survivorship analysis was 100 % for the femoral stem and 95 % for the acetabular cup at 6 years . Of concern was the high polyethylene wear measured with an average of 0.24 mm/y ( range , 0.05 - 0.76 mm/y ) 155 patients ( 171 hips ) with a mean age of 50 years ( 24 - 64 ) were r and omized to uncemented PCA ( 84 hips ) or Harris-Galante type I ( 87 hips ) total hip arthroplasty .  Clinical and radiographic evaluations were done regularly . The improvements in the Harris hip and pain scores did not differ . Osteolysis developed in 5 PCA and 17 Harris-Galante hips . 13 hips in the PCA and 16 in the Harris-Galante ( HG ) group were revised because of mechanical failures and 1 hip ( HG ) because of infection after a mean follow-up of 9 years . Decreased 10-year survival rate , based on revision as end-point , was noted for the PCA ( 85 % ) , compared with the Harris-Galante cup ( 99 % ) . The corresponding survival rate of the PCA stem ( 96 % ) was higher than that observed for the Harris-Galante design ( 86 % ) . When radiographic failures were included , the survival rates of the 4 different components dropped to between 73 % and 94 % . These findings indicate that further revisions will be necessary and continuous radiographic follow-up is indicated to enable revision before severe bone destruction has occurred . Although the PCA and the Harris-Galante design s differed as regards the survival of the individual components , the overall clinical and radiographic survival rates of these cementless total hip arthroplasties were poor Surgery and other invasive therapies are complex interventions , the assessment of which is challenged by factors that depend on operator , team , and setting , such as learning curves , quality variations , and perception of equipoise . We propose recommendations for the assessment of surgery based on a five-stage description of the surgical development process . We also encourage the widespread use of prospect i ve data bases and registries . Reports of new techniques should be registered as a professional duty , anonymously if necessary when outcomes are adverse . Case series studies should be replaced by prospect i ve development studies for early technical modifications and by prospect i ve research data bases for later pre-trial evaluation . Protocol s for these studies should be registered publicly . Statistical process control techniques can be useful in both early and late assessment . R and omised trials should be used whenever possible to investigate efficacy , but adequate pre-trial data are essential to allow power calculations , clarify the definition and indications of the intervention , and develop quality measures . Difficulties in doing r and omised clinical trials should be addressed by measures to evaluate learning curves and alleviate equipoise problems . Alternative prospect i ve design s , such as interrupted time series studies , should be used when r and omised trials are not feasible . Established procedures should be monitored with prospect i ve data bases to analyse outcome variations and to identify late and rare events . Achievement of improved design , conduct , and reporting of surgical research will need concerted action by editors , funders of health care and research , regulatory bodies , and professional societies In a prospect i ve study of 100 consecutive Wagner resurfacing hip arthroplasties in ninety-three patients , the outcomes for all hips were determined for an eight to ten-year follow-up period . By survivorship analysis , the rate of survival of the arthroplasty was calculated to be 70 per cent at five years , but only 40 per cent at eight years . The major cause of failure was aseptic loosening of the acetabular or femoral component , or both . Fracture of the neck of the femur occurred in three hips . Although the medium-term results ( at fifty-six to eighty-three months ) were better than those in most comparable studies of resurfacing arthroplasty , the poor long-term results ( at ninety-one to 118 months ) show that meaningful studies of new prosthetic design s must continue for at least eight years , and , if at all possible , must include 100 per cent follow-up . The survival curve for the resurfacing arthroplasties in this study can serve as the basis for comparison of the early , medium , and long-term results of future design s of resurfacing hip prostheses We report an independent prospect i ve review of the first 230 Birmingham hip resurfacings in 212 patients at a mean follow-up of five years ( 4 to 6 ) . Two patients , one with a loose acetabular component and the other with suspected avascular necrosis of the femoral head , underwent revision . There were two deaths from unrelated causes and one patient was lost to follow-up . The survivorship with the worst-case scenario was 97.8 % ( 95 % confidence interval 95.8 to 99.5 ) . The mean Harris hip score improved significantly ( paired t-test , p < 0.05 ) from 62.54 ( 8 to 92 ) pre-operatively to 97.7 ( 61 to 100 ) at a mean of three years ( 2.1 to 4.3 ) , then deteriorated slightly to a mean of 95.2 ( 47 to 100 ) at a mean of five years . The mean flexion improved from 91.5 degrees ( 25 degrees to 140 degrees ) to 110.4 degrees ( 80 degrees to 145 degrees ) at a mean of three years with no further improvement at five years ( 111.2 degrees ; 70 degrees to 160 degrees ) . On radiological review at five years , one patient had a progressive lucent line around the acetabular component and six had progressive lucent lines around the femoral component . A total of 18 femoral components ( 8 % ) had migrated into varus and those with lucent lines present migrated a mean of 3.8 degrees ( 1.02 degrees to 6.54 degrees ) more than the rest . Superolateral notching of the femoral neck and reactive sclerosis at the tip of the peg of the femoral component were associated with the presence of lucent lines ( chi-squared test , p < 0.05 ) , but not with migration of the femoral component , and are of unknown significance . Our results with the Birmingham hip resurfacing continue to be satisfactory at a mean follow-up of five years We evaluated the clinical and radiographic outcomes of 100 consecutive primary total hip arthroplasties in which a proximally coated anatomically design ed femoral component was fixed without cement for the treatment of primary osteoarthritis . The minimum duration of follow-up was six years ( average , 7.1 years ) . The eighty-eight patients who had the arthroplasties were followed prospect ively with a st and ard clinical evaluation that involved use of the Harris hip score and a radiographic evaluation based on the criteria of the Hip Society . Bone ingrowth was evaluated with the method of Engh et al. The average age of the patients at the time of the operation was 62.6 years ( range , thirty-nine to eighty-four years ) . Fifty-one patients were men and thirty-seven were women . The average preoperative Harris hip score was 48 points , with an average pain score of 15 points and an average function score of 26 points . Nonmechanical complications that necessitated a revision operation included one deep hematogenous infection , one late periprosthetic fracture , and a 0.5-inch ( 1.27-centimeter ) limb-length discrepancy . At the time of the most recent follow-up , the average Harris hip score was 96 points , with an average pain score of 42 points and an average function score of 45 points . The prevalence of pain in the anterior part of the thigh was 5 percent ( five hips ) . One patient had a revision of the femoral component because of aseptic loosening , and one had a revision of the acetabular component because of recurrent dislocations . Radiographic assessment revealed consistent evidence of proximal bone ingrowth . No complete radiolucent line was identified , except around the stem that had loosened . Twenty-seven femoral components were associated with slight pedestal formation . No osteolytic lesion of the femur was identified . Nonprogressive pelvic osteolysis was identified in four hips , but none of the lesions were more than two millimeters in diameter . None of the acetabular components migrated , and no radiolucent line of more than two millimeters in thickness was seen around any acetabular cup . The data from this study , in which the minimum duration of follow-up was six years , indicate that the anatomically design ed prosthesis can provide good results , with low prevalences of pain in the thigh and loosening of the component , in younger , active patients Two series of 100 consecutive primary total hip arthroplasties , each using a single design of noncemented or cemented femoral component ( all 28 mm heads ) , were compared . One cemented and two noncemented stems underwent revision for aseptic loosening . Of unrevised hips , outcome data statistically favored cemented , rather than noncemented , stems . The data for cemented and noncemented stems , respectively , were : An excellent to good result in 97 % versus 88 % ; thigh pain in 3 % versus 40 % ; subsidence in 0 % versus 22 % ; and endosteal cavitation in 6 % versus 12 % . For patients with 25 unrevised matched pairs , selected by gender , age , diagnosis , and weight , outcome data also statistically favored cemented over noncemented stems , respectively : an excellent or good result in 25 versus 20 hips ; thigh pain in two versus eight hips ; and subsidence in none versus six hips . Midterm followup data for these concurrent total hip arthroplasty series of a mid1980s design revealed prevalence of mechanical failure of 1 % for cemented stems and 4 % for noncemented stems . Corroborating matched pair comparison neutralized selection bias as a causative factor for these differences . These data indicate contemporary cemented femoral stem fixation is superior to second generation noncemented femoral stem fixation . Controlled comparative studies at midterm to long term followup , such as in this report , are needed to define outcome and indications for current third generation noncemented stem fixation One hundred and eighty-four patients who had been managed , between 1984 and 1985 , with a total of 204 consecutive primary total hip arthroplasties with insertion of a Harris-Galante type-I acetabular component without cement were prospect ively studied . There were eighty-two men ( 45 per cent ) and 102 women ( 55 per cent ) . The mean age at the time of the operation was fifty-two years ( range , twenty to eighty-four years ) . One hundred and fifty-seven patients ( 173 hips ) were available for clinical review at a mean of 104 months ( range , seventy-eight to 126 months ) . At this time , the mean preoperative Harris hip score of 52 points ( range , 12 to 79 points ) had improved to a mean of 90 points ( range , 44 to 100 points ) . Two patients ( two hips ) had had an exchange of an excessively worn polyethylene liner . One patient ( one hip ) had had débridement and grafting of an area of massive retroacetabular osteolysis . Two stable acetabular components ( 1 per cent ) had been revised at the time of femoral revision . None of the cups had been revised because of aseptic loosening . Radiographic examination of 150 patients ( 165 hips ) at a mean of 104 months ( range , seventy-eight to 126 months ) revealed that 156 cups ( 95 per cent ) were stable . Eight cups ( 5 per cent ) were considered to be possibly unstable , with a radiolucent line between the prosthesis and the bone that was one millimeter wide or less in at least four of five zones ; two of the eight had a complete radiolucent line in all zones . One component , which had been implanted with a bulk allograft from a femoral head , migrated more than two millimeters in the first two years and then stabilized without complication . Osteolysis was seen in seven acetabula ( 4 per cent ) and was limited to the periphery of the cup in six . Survivorship analysis at ten years revealed that the acetabular component had a 99 per cent chance of survival ( 95 per cent confidence interval , 0.98 to 1.0 ) with revision or aseptic loosening as the end point and a 97 per cent chance of survival ( 95 per cent confidence interval , 0.95 to 1.0 ) with revision , aseptic loosening , or reoperation because of a problem related to the acetabular component as the end point AIM The present work aims at evaluating the clinical and radiological long-term results of the Harris-Galante press-fit cup . METHOD At an average follow-up time of 9.5 years ( min . 9 , max . 10.3 ) 123 patients with 138 Harris-Galante press-fit cups ( HGP ) were examined clinical ly and radiology . The clinical evaluation was done with the Harris hip score . Together with the HGP , which was inserted in all cases , five different femoral stems were implanted . A lateral approach , according to the technique of Watson-Jones , was used in all cases . RESULTS The mean follow-up Harris hip score was 89 of 100 points and is assessed as a good result . 7 cups ( 5 % ) were classed as being radiological loose , but only one case had also clinical symptoms . A total of 10 cups ( 6.8 % ) had to be revised . 3 cups ( 2 % ) had to be revised because of aseptic loosening . This result represents a survival rate of 93.2 % according to Kaplan-Meier . CONCLUSION The long-term clinical and radiological results of the Harris-Galante press-fit cup and there fixation method can assessed as good Ninety patients ( 96 hips ) scheduled for THA were stratified to fixation of the acetabular component in three main groups of about equal size . Fluoride cement , porous coated press-fit cup with ceramic coating or Palacos cum Gentamicin cement were used . All patients received Spectron EF stem .  The migration of the cups and the femoral head penetration into the socket were measured with radiostereometric analysis . At 2 years the choice of fixation did not influence the migration or rotation of the cup .  Patients with compromised bone quality showed increased three-dimensional ( 3D or total ) migration . Proximal and 3D penetration rates were increased in cemented compared with the uncemented cups ( p<0.001 ) , which probably not could be related to the choice of fixation . Appearance of radiolucent lines was almost equal in the two cemented groups . Uncemented cups had less radiolucent lines at 2 years . Fluoride containing cement or uncemented fixation did not improve the early postoperative stability of the socket Abstract . We prospect ively studied 250 patients with a proximal hydroxyapatite coated hip prosthesis .  The follow-up period was 5 years . All components showed osseointegration except for one deep infection . The morphology of bone remodeling with either endosteal bone formation or periosteal bone formation was dependent on the way the stem filled the medullary canal . No linear or distal osteolysis around the stems was observed . Résumé . 250 patients avec une prothèse de la hanche revêtue d ' hydroxyapatite  ont été étudiés avec un suivi de 5 années . Tous les composants ont montré une ostéointégration à l'exception d'un cas avec une infection profonde . La formation osseuse endostée ou periostée était dépendante du remplissage du canal médullaire par la tige . Aucune ostéolyse autour des tiges n'a été observée The early migration of porous acetabular cups was studied in 43 patients with osteoarthrosis . The patients were r and omly allocated to additional fixation of the cup with either biodegradable poly-L-lactic acid screws or titanium screws .  Radiostereometric evaluation was done during the first 2 years after the procedure in 43 hips ( 23 with  poly-L-lactic acid screws and 20 with titanium screws ) . At the 2-year follow-up , cups fixed with poly-L-lactic acid screws had migrated significantly more in the proximal-distal ( p < 0.05 ) and medial-lateral ( p < 0.05 ) directions . Cups with titanium screws displayed more pronounced rotations around the longitudinal axis ( p < 0.05 ) . Postoperatively , on the lateral view , there was an increased occurrence of radiolucencies at the dome of the cups fixed with poly-L-lactic acid screws ( p < 0.05 ) . The clinical result did not differ between the two groups . Inferior implant-bone contact in the poly-L-lactic acid group , local changes of the bone quality , and diminishing support of the poly-L-lactic acid screws  caused by their degradation with time could be reasons for the different pattern of migration observed At the authors ' hospital , 410 primary total hip replacements were performed on 372 patients between September 1 , 1985 , and May 31 , 1989 . All hips were assigned r and omly to receive a Charnley prosthesis with an ogee flanged cup or a Spectron prosthesis with a metal backed cup .  Eleven-year survivor analysis , using revision as the end point definition of failure , revealed a survival rate of 93.2 % ± 5.8 % for the Charnley replacement and 95.9 % ± 3.0 % for the Spectron . If each component of the systems was analyzed ( concerning aseptic loosening ) , the ogee cup and the Spectron stem had 100 % survival . The survivorship for all 410 hips was 94.5 % ± 3.4 % . If the end point definition of failure was exp and ed to include patient dissatisfaction , the survival rate decreased to 86.3 % ± 4.9 % . These survival rates were compared with the rates obtained by the Swedish National Hip Registry . The national cohort included all patients in Sweden who were treated surgically with a Charnley ( 14,053 patients ) or Spectron ( metal backed cup ) prosthesis ( 726 patients ) between September 1 , 1985 , and May 31 , 1989 .  Eleven-year survivor analysis revealed a national survival rate of 92.1 % ± 0.7 % for the Charnley replacement and 88.6 % ± 6.1 % for the Spectron . The analyses from the Swedish Registry are based on more than 160,000 primary operations and 11,500 revisions . Despite the enormous amount of data , there are drawbacks , and registries never can replace the prospect i ve , r and omized trial . One reason is the Swedish National Registry is unable to discriminate between the individual cup and stem components when analyzing the cause of revision , and no clinical or radiographic information is collected . A potential drawback for the r and omized trial is performance bias because surgeons from specialized centers might perform better than the general orthopaedic surgeon The senior author systematic ally began collecting preoperative and postoperative data on all the total hip arthroplasties he performed starting in July 1970 . The data collected represent a 26-year experience using practice surveillance ( preoperative and regular interval postoperative collection and analysis of outcomes ) as a method to document the outcome of the total hip arthroplasty procedure and as a method to evaluate the need for changes in the procedure . As the senior author made few selected changes in the operative procedure during the followup period , the primary author has been able to evaluate the change in outcome based on these changes . The six studies reported in the current study show the durability of the long-term results of cemented total hip arthroplasty , the improvement in radiographic reproducibility obtained on the femoral side of the construct with improved cementing techniques , the deleterious effects of using cable to reattach the greater trochanter , the deleterious effects of changing femoral component design that included a change in surface finish , the improvement in acetabular fixation using cementless fixation , and the optimization of bearing surface wear using smaller diameter femoral heads . All of these findings have been incorporated into the primary surgeon 's practice based on this practice surveillance . As shown , practice surveillance also has provided a tool for performing clinical research . Although practice surveillance of controlled cohorts never will supplant prospect i ve r and omized clinical trials in evidence based medicine , it should help each surgeon with his or her own practice and can be used as an important research tool to study the optimization of outcomes of a surgical procedure BACKGROUND The use of cementless , proximally porous-coated femoral stems for total hip arthroplasty has increased in popularity . The purpose of the present report was to examine the five to ten-year results associated with the use of a so-called second-generation circumferentially proximally porous-coated titanium-alloy stem . METHODS Between 1991 and 1994 , 123 Harris-Galante Multilock femoral stems were implanted in 101 patients . The average age of the patients at the time of surgery was 53.8 years . The patients were followed prospect ively and were reevaluated at a minimum of five years postoperatively . No patient was lost to follow-up . Twenty-five patients ( thirty hips ) were interviewed by telephone , and four patients ( five hips ) died during the study period because of problems that were unrelated to the operation . The remaining seventy-two patients ( eighty-eight hips ) had a minimum of five years of clinical and radiographic follow-up . RESULTS The average duration of follow-up was seventy-eight months . At the time of the most recent follow-up , the average Harris Hip Score was 95 points . Eighty-seven ( 99 % ) of eighty-eight stems were biologically stable , with eighty-four hips ( 95 % ) having osseous ingrowth and three hips ( 3 % ) having stable fibrous fixation . One stem was revised because of loosening . Thirty-three hips ( 38 % ) had minimal proximal osteolysis , and no hip had diaphyseal osteolysis . Seventy-two hips ( 82 % ) had some degree of stress-shielding in the proximal metaphysis , but only two hips had cortical resorption . None of these patients required additional surgery , and all reported a satisfactory outcome . CONCLUSIONS Given the young age and high activity level of these patients , this stem fared well : the levels of patient function and satisfaction were high , the rates of loosening and revision were very low , and distal osteolysis did not occur . Osseous fixation occurred reliably . Proximal stress-shielding was seen but did not seem to be clinical ly important 60 patients with arthrosis who received a Charnley total hip replacement were r and omly assigned to either an uncemented porous Harris-Galante type I socket or a cemented all-polyethylene Charnley socket .  Socket migration and rotation were studied by radiostereometry ( RSA ) for 2 years . After 2 years , all sockets were still in situ . There was no difference in migration or rotation between the 2 socket design s , nor was there any difference in pain or function . We conclude that the initial fixation of the Harris-Galante socket resembles that of the Charnley socket Background Minor design changes may cause major changes in implant performance . Thus , as part of a stepwise introduction of a new low-profile cup , we performed a r and omized trial comparing it to a well-docu-mented st and ard cup . Patients and methods 60 patients , stratified according to sex , weight , and age , underwent cemented total hip arthroplasty using a Lubinus SP2 stem with ceramic head  and were r and omized to either the new low-profile Lubinus Flanged Anti-Luxation cup ( FAL ) or the Lubinus St and ard Eccentric cup ( St and ard ) .  7 patients were excluded and 53 ( 28 FAL ) were evaluated at 3 , 6 , 12 , and 36 months postoperatively . Primary outcome variables , cup migration ( MTPM ) , and wear ( total 3-dimensional femoral head penetration ) were measured with radiostereometry ( RSA ) . Clinical outcome was evaluated with the western Ontario and McMaster osteoarthritis index ( Womac ) and the visual analog pain score ( VAS ) . Results We found no difference in migration between the FAL and St and ard cups . There was no difference in wear between the two cups and there was no correlation between wear and migration . 3 cups ( 2 FAL and 1 St and ard ) showed continuous migration of a magnitude that indicated an increased risk of early loosening . Clinical outcome was excellent , without any difference between the 2 groups The Anatomique Benoist Girard ( ABG ) I total hip arthroplasty has been widely used in Europe since 1989 . Two recent midterm reports have shown high rates of component failure secondary to polyethylene wear . To further investigate this issue , our study prospect ively follows 157 consecutive primary total hip arthroplasties using the ABG I prosthesis at an average follow-up of 10 years .  Clinical outcomes have been excellent , although the incidence of thigh pain was 7.2 % . Radiographic evaluation of the cup showed eccentric polyethylene wear in 93.6 % of the patients . The average polyethylene linear wear was 2.40 mm , whereas the average annual wear rate was 0.25 mm/y . There were 7 hips ( 5.6 % ) with severe periacetabular osteolysis . Nine revisions were performed for loosening or wear . The overall component survival rate was 92.6 % . The overall survival rate was 92.6 % ( confidence interval , 78.55 - 96.47 ) for the acetabular component and 96.3 % ( confidence interval , 85.67 - 100 ) for the femoral component . Although the clinical and radiographic results of the ABG I total hip arthroplasty in this series have been acceptable , high rates of polyethylene wear , most likely related to sterilization by gamma-irradiation in air , have been the limiting factor in the long-term success of this design Background : Second-generation cementless femoral components were design ed to provide more reliable ingrowth and to limit distal osteolysis by incorporating circumferential proximal ingrowth surfaces . We examined the eight to eleven-year results of total hip arthroplasty with a cementless , anatomically design ed femoral component and a cementless hemispheric acetabular component . Methods : Ninety-two consecutive primary total hip arthroplasties with implantation of a femoral component with a circumferential proximal porous coating ( Anatomic Hip ) and a cementless hemispheric porous-coated acetabular component ( Harris-Galante II ) were performed in eighty-five patients . These patients were prospect ively followed clinical ly and radiographically . Six patients ( seven hips ) died and five patients ( seven hips ) were lost to follow-up , leaving seventy-four patients ( seventy-eight hips ) who had been followed for a mean of ten years ( range , eight to eleven years ) . The mean age at the time of the arthroplasty was fifty-two years . Results : The mean preoperative Harris hip score of 51 points improved to 94 points at the time of final follow-up ; 86 % of the hips had a good or excellent result . Thigh pain was reported as mild to severe after seven hip arthroplasties . No femoral component was revised for any reason , and none were loose radiographically at the time of the last follow-up . Two hips underwent acetabular revision ( one because of dislocation and one because of loosening ) . Kaplan-Meier survivorship analysis was performed with revision or loosening of any component as the end point . The ten-year survival rate was 96.4 % ± 2.1 % for the total hip prosthesis , 100 % for the femoral component , and 96.4 % ± 2.1 % for the acetabular component . Radiolucencies adjacent to the nonporous portion of the femoral component were seen in sixty-eight ( 93 % ) of the -seventy-three hips with complete radiographic follow-up . Femoral osteolysis proximal to the lesser trochanter was noted in four hips ( 5 % ) . No osteolysis was identified distal to the lesser trochanter . Periacetabular osteolysis was identified in twelve hips ( 16 % ) . Five patients underwent exchange of the acetabular liner because of polyethylene wear . Conclusions : This second-generation cementless , anatomically design ed femoral component provided excellent clinical and radiographic results with a 100 % survival rate at ten years . The circumferential porous coating of this implant improved ingrowth and prevented distal osteolysis at a mean of ten years after the arthroplasty In this issue of Spine , a novel method for managing chronic discogenic low back pain with a thermal intradiscal catheter is reported . This study raises some general questions regarding the introduction of new treatment techniques and devices . Decisions about medical treatment should be based on a careful appraisal of the best evidence available . A step-wise introduction is necessary to increase the use of evidence -based decision making in the implementation of new surgical techniques and implants while exposing as few patients as possible to the potential risk of failure . The development of the total hip arthroplasty procedure , for example , could have been different if the introduction of new devices and techniques had been done more carefully and performed in a step-wise manner . Inferior properties could have been revealed earlier , thus reducing the number of failures and allowing for necessary improvements . It is also desirable , therefore , that members of this profession agree on a st and ardized way to introduce new surgical techniques and implants in the field of spinal disorders . Based on the results of Swedish reports and practice , the following schedule for step-wise clinical introduction of new implants is suggested ( Figure 1 ) : The initial step is a pre clinical testing and is beyond the scope of this discussion . The first clinical step is the open prospect i ve and preferably r and omized trial that includes a minimum of patients but yields a relevant evaluation . The strict rules of prospect i ve , r and omized trials should be adhered to . In this first clinical phase , methods associated with high accuracy , such as radiostereometric analysis ( RSA ) , are required . Within 6 to 24 months , this method has the potential to identify implants/ methods that provide inferior fixation and increased polyethylene wear . Results from this first step determine whether further clinical evaluation is worthwhile . It should be noted and stressed that all types of complications can not be predicted and that further follow-up study is necessary . If favorable results are obtained in the first step , the second step , a multicenter trial exposing the new procedure to a broader aspect in the orthopedic community , can be initiated . In the first step , there is a risk for susceptibility and performance bias because the inventors themselves often perform this introductory investigation . The protocol in the multicenter trial must be prepared carefully and agreed on by all participating inventors . A sufficient number of patients should be included to allow adequate statistical analysis . The ultimate goal for step two is to make even the multicenter trial r and omized by using well-documented methods /implants as the gold st and ard . The final step in the evaluation , step three , is to include a continuous control group by using register studies based on large cohorts to reveal early or unusual and potential clinical catastrophic complications . In a rather small and closed community such as Sweden , the register should be nationwide and include all units in a specific field . When applying the principles for step-wise introduction to the investigation of chronic discogenic low back pain with a  thermal intradiscalcatheterbySaal  and Saal , oneobserves that the current study falls between the pre clinical step and step one . The lack of r and omization toward either conservative or surgical intervention is a definite limitation of the study , and before this method is introduced to a larger study group , a r and omized trial must be considered . A multicenter trial exposing the new procedure to a broader aspect of the orthopedic community is recommended before using it in general orthopedic practice . The length of the follow-up period was very short in this study , and no long-term clinical conclusions can be drawn based on the results Roentgen stereophotogrammetry was used to measure the migration of the centre of the femoral head in 84 cemented Lubinus SP I hip arthroplasties ( 58 primary operations , 26 revisions ) . Four to seven years later , seven femoral components had been revised because of painful loosening . These implants showed greater subsidence , medial migration and posterior migration during the first two postoperative years than did the hips which had not been revised . Six months after operation , subsidence of more than 0.33 mm combined with a total migration of more than 0.85 mm predicted an increased risk of subsequent revision ; the amount of subsidence at two years was an even better predictor . The probability of revision was greater than 50 % if the subsidence at two years was 1.2 mm or more We evaluated the mechanical , chemical and clinical properties of Boneloc cement using radiostereometry and a series of laboratory tests . Compared to a st and ard cement ( Palacos ) the new cement displayed reduced tensile strength , elastic modulus , curing and glass transition temperatures . The amount of MMA extracted during 3 weeks in methanol was smaller for the Boneloc , but the total amount of released monomers was larger . The adhesion to stainless steel and bone did not differ . Radiostereometric analysis during the first postoperative year in 30 patients r and omized to fixation of hip prostheses using either of the 2 cements displayed increased proximal migration of the cup and increased stem subsidence when Boneloc had been used . Part of the stem subsidence occurred inside the cement mantle . On the basis of these findings , we conclude that the inferior fixation in the Boneloc group is mainly caused by its mechanical properties . Other mechanisms , such as increased release of monomers , may also be important Twenty-one patients who had primary osteoarthrosis were managed with a bilateral total hip arthroplasty with insertion of a Charnley femoral component . In each patient , one hip was r and omly allocated to have a Harris-Galante acetabular component inserted without cement , and the contralateral hip was treated with an all-polyethylene Charnley acetabular component fixed with cement . The clinical result was satisfactory in all patients . All forty-two hips were followed , with respect to migration of the acetabular component , with use of roentgenstereophotogrammetric analysis for a median of twenty-seven months ( range , twenty-three to forty-nine months ) . Each patient served as his or her own control . Maximum migration in any direction was 1.7 and 2.1 millimeters , and maximum rotation was 2.2 and 2.0 degrees for the Harris-Galante and Charnley acetabular components , respectively . There was no significant difference in migration between the two design s of acetabular components ( p = 0.98 , p = 0.75 , and p = 0.06 for the transverse , longitudinal , and sagittal axes , respectively ) . However , the Harris-Galante acetabular components  rotated significantly more than the Charnley acetabular components around two of the three axes ( p = 0.008 , p = 0.08 , and p = 0.03 for the transverse , longitudinal , and sagittal axes , respectively ) . The Charnley hip implant has been used clinical ly for a long time , with successful results . Comparison of new design s of implants with the Charnley prosthesis is therefore important . Roentgenstereophotogrammetric analysis provides a potential for detection of problems with fixation at an early stage rather than after long-term follow-up . No major difference in terms of skeletal fixation was found between the two design s of components after short to medium-term follow-up The possibility of migration of cementless cups in total joints after prophylaxis of heterotopic ossification with irradiation or nonsteroidal antiinflammatory drugs  is a concern . Data investigating component stability with digital methods are lacking . This prospect i ve study analyzed the migration of cementless cups  after indomethacin and irradiation prophylaxis  with the digital Einzel-Bild-Röntgen-Analyse tool . The irradiation group ( 106 hips ) and the indomethacin group ( 98 hips ) were compared with 82 hips that did not receive any prophylaxis . The same cementless acetabular implants were used in all cases , and patients were observed clinical ly and radiographically at 2 and 5 years . At the 5-year followup , the number of cups that showed migration greater than 1 mm in the irradiation group ( five ) , the indomethacin group ( three ) , and the control group ( four ) were not different . No cup was considered loose on the radiographs and no patient underwent revision surgery . The results of our study indicate irradiation or short-course use of indomethacin for prophylaxis of heterotopic ossification did not negatively affect the stability of cementless cups in primary total hip arthroplasties . Level of Evidence : Level II , prognostic study . See the Guidelines for Authors for a complete description of levels of evidence
target: INTERPRETATION There was a clinical ly relevant association between early migration of acetabular cups  and late revision due to loosening .
background: BACKGROUND AND PURPOSE The association between excessive early migration of acetabular cups  and late aseptic revision has been scantily reported .
  We therefore performed 2 parallel systematic review s and meta-analyses to determine the association between early migration of acetabular cups  and late aseptic revision .