The beneficial effect of hydroxyapatite lasts Good diagnostic performance of early migration as a predictor of late aseptic loosening of acetabular cups: results from ten years of follow-up with Roentgen stereophotogrammetric analysis (RSA). Early migration predicts late aseptic failure of hip sockets. [What effect does the hydroxyapatite coating have in cementless knee arthroplasty?]. Early migration and late aseptic failure of proximal femoral prostheses. Hydroxyapatite coating versus cemented fixation of the tibial component in total knee arthroplasty: prospective randomized comparison of hydroxyapatite-coated and cemented tibial components with 5-year follow-up using radiostereometry. The Johnson-Elloy (Accord) total knee replacement. Poor results at 8 to 12 years. Denosumab reduces early migration in total knee replacement Fixation of high-flexion total knee prostheses: five-year follow-up results of a four-arm randomized controlled clinical and roentgen stereophotogrammetric analysis study. Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component. Seven-to-Ten-Year Results* Migration of a cemented fixed-bearing, polished titanium tibial baseplate (Genesis II) at ten years : a radiostereometric analysis. The Mayo Cementless Femoral Component in Active Patients with Osteoarthritis Clodronate prevents prosthetic migration: A randomized radiostereometric study of 50 total knee patients Cemented tibial component fixation performs better than cementless fixation Results of Charnley total hip arthroplasty at a minimum of thirty years. A concise follow-up of a previous report. Problems With Cementless Total Knee Arthroplasty at 11 Years Followup Cemented versus cementless Oxford unicompartmental knee arthroplasty using radiostereometric analysis: a randomised controlled trial. Hydroxyapatite-Enhanced Tibial Prosthetic Fixation Early Migration Pattern of the Uncemented CLS Stem in Total Hip Arthroplasties Proximally cemented versus uncemented Freeman-Samuelson knee arthroplasty. A prospective randomised study. Early Migration of the Tibial Component of the Buechel-Pappas Total Ankle Prosthesis Highly Crosslinked Polyethylene Does Not Reduce Aseptic Loosening in Cemented THA 10-year Findings of a Randomized Study Systematic review automation technologies Effect of bioactive coating of the tibial component on migration pattern in uncemented total knee arthroplasty: a randomized RSA study of 14 knees presented according to new RSA-guidelines Long-term comparison of mobile-bearing vs fixed-bearing total knee arthroplasty. Early Inducible Displacement of Tibial Components in Total Knee Prostheses Inserted with and without Cement. A Randomized Study with Roentgen Stereophotogrammetric Analysis* The Unispacer knee implant: early clinical results. Mobile-bearing lateral unicompartmental knee replacement with the Oxford domed tibial component: an independent series. Lateral unicompartmental knee replacement: fixed or mobile bearing? Issues related to the conduct of systematic reviews: a focus on the nutrition field. Results of Charnley total hip arthroplasty with use of improved femoral cementing techniques. a concise follow-up, at a minimum of twenty-five years, of a previous report. 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. Preoperative gait patterns and BMI are associated with tibial component migration The Bisurface Total Knee Replacement: A Unique Design for Flexion Four-to-Nine-Year Follow-up Study* Absence of a Tourniquet Does Not Affect Fixation of Cemented TKA: A Randomized RSA Study of 70 Patients. A randomized study on migration of the Spectron EF and the Charnley flanged 40 cemented femoral components using radiostereometric analysis at 2 years Hybrid Total Hip Arthroplasty with a Precoated Offset Stem: Four to Nine-Year Results* Symposium integrating evidence-based medicine into clinical practice.
Background and purpose In contrast to early migration , the long-term migration of hydroxyapatite- ( HA- ) coated tibial components in TKA has been scantily reported . This r and omized controlled trial investigated the long-term migration measured by radiostereometric analysis ( RSA ) of HA-coated , uncoated , and cemented tibial components in TKA . Patients and methods 68 knees were r and omized to HA-coated ( n = 24 ) , uncoated ( n = 20 ) , and cemented ( n = 24 ) components .  All knees were prospect ively followed for 11–16 years , or until death or revision .  RSA  was used to evaluate migration at yearly intervals . Clinical and radiographic evaluation was according to the Knee Society system . A generalized linear mixed model ( GLMM , adjusted for age , sex , diagnosis , revisions , and BMI ) was used to take into account the repeated-measurement design . Results The present study involved 742 RSA analyses . The mean migration at 10 years was 1.66 mm for HA , 2.25 mm for uncoated and 0.79 mm for the cemented group ( p < 0.001 ) . The reduction of migration by HA as compared to uncoated components was most pronounced for subsidence and external rotation . 3 tibial components were revised for aseptic loosening ( 2 uncoated and 1 cemented ) , 3 for septic loosening ( 2 uncoated and 1 cemented ) , and 1 for instability ( HA-coated ) . 2 of these cases were revised for secondary loosening after a period of stability : 1 case of osteolysis and 1 case of late infection . There were no statistically significant differences between the fixation groups regarding clinical or radiographic scores .  Interpretation HA reduces migration of uncemented tibial components . This beneficial effect lasts for more than 10 years . Cemented components showed the lowest migration . Longitudinal follow-up of TKA with RSA allows early detection of secondary loosening BACKGROUND Excessive early migration of femoral stems following total hip arthroplasty and tibial components following total knee arthroplasty is associated with their long-term survival and allows reliable early evaluation of implant performance . However , a similar relationship involving acetabular components following hip arthroplasty has not been evaluated . This prospect i ve , long-term study with clinical and Roentgen stereophotogrammetric analysis ( RSA ) follow-up establishes the existence of this relationship and its associated diagnostic performance . METHODS Thirty-nine consecutive patients ( forty-one hips ) who underwent total hip arthroplasty with a cemented Exeter stem and a cemented Exeter all-polyethylene cup had prospect i ve clinical and RSA follow-up . Patients were evaluated postoperatively at six weeks , at three , six , and twelve months , and annually thereafter . Conventional anteroposterior and lateral radiographs were made at six weeks and at two , five , and ten years postoperatively as well as when indicated . The mean duration of follow-up ( and st and ard deviation ) was 9.4 ± 3.2 years . No patients were lost to follow-up ; fifteen patients died during the follow-up period . RESULTS Eleven acetabular components were observed to be loose on conventional radiographs after a mean of seventy-six months ( range , twelve to 140 months ) . During the first two postoperative years , the failed acetabular components showed markedly greater and more rapid cranial translation and sagittal rotation . Both cranial translation ( hazard ratio = 19.9 [ 95 % confidence interval , 4.94 to 80.0 ] , p < 0.001 ) and sagittal rotation ( hazard ratio = 11.1 [ 95 % confidence interval , 2.83 to 43.9 ] , p = 0.001 ) were strong risk factors for late aseptic loosening . Eight of the eleven failed components showed a distinctive pattern of excessive cranial translation combined with excessive sagittal rotation . The associated diagnostic performance of two-year cranial translation and /or sagittal rotation for predicting late aseptic loosening of the acetabular component was good ( area under the receiver operating characteristic curve , 0.88 [ 95 % confidence interval , 0.74 to 1.00 ; p < 0.001 ] and 0.84 [ 95 % confidence interval , 0.68 to 1.00 ; p = 0.001 ] , respectively ) . CONCLUSIONS Early migration , as measured by RSA at two years postoperatively , has good diagnostic capabilities for the detection of acetabular components at risk for future aseptic loosening , and this method appears to be an appropriate means of assessing the performance of new implants or implant-related changes We report a prospect i ve , stratified study of 60 PCA-cups and 60 RM-polyethylene cups which have been followed for a median time of 90 months , with annual radiography .  The radiological migration of cups was measured by the computer-assisted EBRA method . A number of threshold migration rates from 1 mm in the first year to 1 mm in five years have been assessed and related to clinical ly determined revision rates . A total of 28 cups showed a total migration of 1 mm or more within the first two years ; 13 of these cups have required revision and been exchanged . The survival curves of cups which had previously shown early migration were considerably different from those without early migration . For cups with a migration of less than 1 mm within the first two years the mean survival at 96 months was 0.96 + /- 0.02 ; for migrating cups , it was 0.63 + /- 0.11 ( log-rank test , p=0.0001 ; chi-square value=39.4 ) . Early migration is a good predictor for late loosening of hip sockets The goal of this study was to compare the migration of  noncemented diffusion sintered titanium fibermesh-coated tibial components with ( HA group ) and without ( non-HA group ) additional hydroxyapatite coating .  For this purpose  digital radiostereometry ( DIRSA ) was used to compare the migration after 2 and 9 years for the two groups . After 2 years the mean maximum subsidence of the HA-coated components ( 0.24+/-0.18 mm ) was about one-half of the mean maximum subsidence of the non-HA-coated group ( 0.55+/-0.55 mm ) . After 9 years the maximum subsidence of the HA-coated components was still smaller , but not as pronounced as before . The same trend was also found for the endpoint maximum total point motion ( MTPM ) . After 2 years the mean MTPM of the HA-coated components was 0.66+/-0.38 mm and of the non-HA group 0.73+/-0.50 mm . After 9 years the mean MTPM for the HA-coated components was 0.54+/-0.15 mm and for the non-HA-coated components 0.74+/-0.20 mm . None of the HA-coated tibial components but one of the non-HA group had to be revised and exchanged due to aseptic loosening The  vertical migration of four configurations of a proximal femoral prosthesis , followed for up to nine years , was measured on st and ard radiographs . The same implant was used without cement ( group 1 ) and with cement ( group 2 ) . The migration of both groups was linear from six months onwards . The mean migration rate and the incidence of late aseptic loosening were both greater in group 1 . Survival analysis of the two groups , however , showed no statistically significant difference . In both groups , hips later destined for revision migrated more rapidly from the initial postoperative period onwards , than did the remainder . A threshold migration of 1.2 mm/year during the first two years after implantation detected hips likely to fail with a specificity of 86 % and a sensitivity of 78 % . This ' migration test ' was applied to the results in two further groups of patients in which a modified femoral prosthesis had been implanted without hydroxyapatite coating ( group 3 ) and with hydroxyapatite coating  ( group 4 ) . The test distinguished between the four groups and suggested that at least two fixation procedures should be ab and oned . We conclude that vertical migration measured on st and ard radiographs in the first two years after implantation can be used to predict late aseptic loosening . New prosthetic configurations should be evaluated by migration measurements before their general release . Our observations support the view that one cause of late aseptic loosening is imperfect initial fixation Fifty-three consecutive patients ( 57 knees ; mean age , 69 years ) entered a prospect i ve r and omized study to compare the fixation of hydroxyapatite (HA)-coated ( 29 knees ) with cemented ( 28 knees ) tibial components in the Tricon II total knee arthroplasty . The quality of the fixation during 5 years postoperatively was evaluated with radiostereometric analysis ( RSA ) . Three HA-coated implants were revised : 2 owing to infection , and 1 owing to early delamination of the coating and clinical loosening . Eight patients ( 9 knees ) died , 1 patient sustained a stroke  , and 1 patient refused investigations after 1 year . In the 40 patients ( 19 HA-coated , 21 cemented ) remaining at 5 years , the magnitude of the micromotion between the HA-coated and cemented groups did not differ . The HA-coated implants displayed most of the migration within the initial 3 months then stabilized , whereas the cemented implants showed an initially lower , but over time continuously increasing migration . Between 1 and 2 years , 4 of 24 HA-coated and 10 of 23 cemented implants  migrated > 0.2 mm and were categorized unstable , which has been shown to have a prognostic value as regards future aseptic loosening . Progressive radiolucent lines developed in 2 cemented knees , which both were categorized unstable . If HA-coated implants can sustain the forces that threaten the fixation in the early period after implantation , a strong and enduring fixation may be obtained We have found poor mid-term results in a multisurgeon series of 94 Johnson-Elloy ( Accord ) total knee replacements .  A total of 27 knees ( 29 % ) has required revision , in 26 for aseptic loosening . Only 18 ( 19 % ) remain in situ , and these give poor function , are painful and most show radiological evidence of early failure . At 12 to 13 years the survival rate is 43 % ( confidence interval 29 to 57 ) with failure requiring revision as the endpoint . Proximal migration of the femoral component is associated with considerable loss of bone stock . We believe that all patients who have this implant should be recalled for regular review in order to anticipate this problem Background and purpose — Aseptic loosening is a main cause of late revision in total knee replacement ( TKR ) . Migration of implants as measured by radiostereometric analysis ( RSA ) can predict future loosening . This migration is associated with bone resorption . Denosumab is a human monoclonal antibody that binds to receptors on osteoclast precursors and osteoclasts . This prevents osteoclast formation , result ing in less bone resorption in cortical and trabecular bone . We investigated whether denosumab can reduce migration of TKR , as measured with RSA . Patients and methods — In this 2-center , r and omized , double-blind  placebo-controlled  trial , 50 patients with osteoarthritis of the knee were treated with an injection of either denosumab ( 60 mg ) or placebo 1 day after knee replacement surgery and again after 6 months . RSA was performed postoperatively and after 6 , 12 , and 24 months . The primary effect variable was RSA maximal total point motion ( MTPM ) after 12 months . We also measured other RSA variables and the knee osteoarthritis outcome score ( KOOS ) . Results — The primary effect variable , MTPM after 12 months , showed that migration in the denosumab group was statistically significantly less than in the controls . Denosumab  MTPM 12 months was reduced by one-third ( denosumab : median 0.24 mm , 10 % and 90 % percentiles : 0.15 and 0.41 ; placebo : median 0.36 mm , 10 % and 90 % percentiles : 0.20 and 0.62 ) . The secondary MTPM variables ( 6 and 24 months ) also showed a statistically significant reduction in migration . There was no significant difference in MTPM for the period 12–24 months . KOOS sub-variables were similiar between denosumab and placebo after 12 and 24 months . Interpretation — Denosumab reduces early migration in total knee replacement , as in previous trials using bisphosphonates . As migration is related to the risk of late loosening , denosumab may be beneficial for long-term results BACKGROUND High-flexion total knee arthroplasty was introduced to meet the dem and s of daily activity requiring increased knee flexion . However , concerns have been raised regarding the fixation of high-flexion total knee arthroplasty components and increased rates of loosening have been reported . To date , migration , and thus fixation , of high-flexion total knee arthroplasty components has not been analyzed and the preferential bearing type ( mobile or fixed ) is unknown . METHODS Of eighty-six consecutive eligible patients , seventy-four patients ( seventy-eight knees ) scheduled for total knee arthroplasty were r and omized to one of four  Legacy Posterior Stabilized ( LPS ) total knee prosthesis design s : ( 1 ) LPS-Flex mobile , ( 2 ) LPS-Flex fixed , ( 3 ) LPS mobile , and ( 4 ) LPS fixed . The primary outcome was component migration measured with use of Roentgen stereophotogrammetric analysis , and secondary outcomes were postoperative knee flexion and extension and Knee Society Score . Patients were evaluated postoperatively at six , twelve , twenty-six , and fifty-two weeks and annually thereafter . At the five-year follow-up , eight patients had died and two patients were lost to follow-up . Seventy-seven tibial and forty-two femoral components were suitable for migration measurements . RESULTS The overall five-year migration of the seventy-seven tibial components was not significantly different among the four total knee prosthesis design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.02 to 0.25 mm ) and migration was comparable at the two and five-year follow-up . Migration stabilized in all but three components ( two LPS-Flex mobile and one LPS fixed ) ; one of these components has already been revised and was aseptically loose . The overall five-year migration of the forty-two femoral components was comparable among the four design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.01 to 0.18 mm ) and was similar at two and five years postoperatively . One femoral component ( LPS-Flex mobile ) migrated excessively . In patients who had a mean postoperative flexion of ≥ 125 ° or a maximum flexion of ≥ 135 ° during the one to five-year follow-up period , migration of high-flexion components was comparable with that of conventional components and indicative of appropriate fixation . Postoperative flexion , extension , Knee Society Score , and Knee Society Score function were comparable during the five-year follow-up period and at the two and five-year follow-up . CONCLUSIONS The LPS-Flex total knee prosthesis with either a mobile or a fixed bearing had migration comparable that of with its conventional counterpart and is expected to have similar ( excellent ) long-term survival in these patients . LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence 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 AIMS The purpose of the present study was to examine the long-term fixation of a cemented fixed-bearing polished titanium tibial baseplate ( Genesis ll ) . PATIENTS AND METHODS Patients enrolled in a previous two-year prospect i ve trial ( n = 35 ) were recalled at ten years . Available patients ( n = 15 ) underwent radiostereometric analysis ( RSA ) imaging in a supine position using a conventional RSA protocol . Migration of the tibial component in all planes was compared between initial and ten-year follow-up . Outcome scores including the Knee Society Score , Western Ontario and McMaster Universities Arthritis Index , 12-item Short Form Health Survey , Forgotten Joint Score , and University of California , Los Angeles Activity Score were recorded . RESULTS At ten years , the mean migration of the tibial component was less than 0.1 mm and 0.1 ° in all planes relative to the post-operative RSA exam . Maximum total point movement increased with time ( p = 0.002 ) from 0.23 mm ( sd 0.18 ) at six weeks to 0.42 mm ( sd 0.20 ) at ten years . CONCLUSION The low level of tibial baseplate migration found in the present study correlates to the low rate of revision for this implant as reported in individual studies and in joint replacement registries . TAKE HOME MESSAGE Overall , the implant was found to be well fixed at ten years , supporting its continued clinical use and the predictive power of RSA for determining long-term fixation of implants . Cite this article : Bone Joint J 2016;98-B:616 - 21 This prospect i ve study reports the clinical and radiological results of a single-surgeon series using the Mayo conservative hip stem in a district hospital . 30 total hip arthroplasties were performed in 26 physically active patients . There were 18 women and 8 men , with a mean age of 57.4 years ( range 36–79 ) . 4 cases were bilateral . The operation was performed for severe primary or secondary osteoarthritis of the hip . Duration of follow-up ranged from 67–87 months ( mean 81 months ) . There were no early complications relating to the surgical procedure . There was one case of traumatic fracture of the femur during rehabilitation , while late complications included two cases of late infection ( 4 months and 16 months after surgery ) both revised in two-stage procedures . There was considerable improvement in Merle d'Aubigne score following surgery . There were no revisions for aseptic loosening , but we identified 2 implants with significant radiolucent lines and subsidence six years after the index operation . Neither patient experienced pain in the hip or restriction of activity . Therefore , the aseptic loosening survival rate was 100 % ( end point = revision operation ) . Taking radiological loosening as the end point survivorship was 93.3 % . The use of the Mayo short stem component in active patients may preserve bone and enable subsequent revision operations to proceed using primary implants . Our results suggest that conservative design s of this type may be of benefit in selected individuals In a double-blind study , we r and omized 50 patients to receive peroral clodronate medication or placebo from 3 weeks before until 6 months after a total knee replacement with a cemented NexGen implant .  Migration of the tibial components was measured by radiostereometry at 1 year . Clodronate reduced prosthetic migration , as measured by maximum total point motion , from 0.40 mm to 0.29 mm ( p = 0.01 ) . This confirms that the early postoperative migration is related to bone resorption and thus the biology of the bone bed . Since early migration is related to late loosening , 6 months of clodronate medication might reduce the risk of loosening Background The question whether the tibial component of a total knee arthroplasty  should be fixed to bone with or without bone cement has not yet been definitely answered . We studied movements between the tibial component and bone by radiostereometry ( RSA ) in total knee replacement ( TKR ) for 3 different types of fixation : cemented fixation ( C-F ) , uncemented porous fixation ( UC-F ) and uncemented porous hydroxyapatite fixation ( UCHA-F ) . Patients 116 patients with osteoarthrosis , who had 146 TKRs , were included in 2 r and omized series . The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation . The second series included 30 patients who had simultaneous bilateral TKR surgery , and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation . Results After 5 years 2 knees had been revised , neither of which were due to loosening . 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result , and is a pending failure . The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years . UCHA-F  migrated less than UC-F after 1 year . Interpretation Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation . When using uncemented components , however , there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year The purpose of the current study was to up date the results of a prospect i ve , single-surgeon series of primary Charnley total hip arthroplasties performed with cement . This investigation is one of the first studies in which hips treated with total hip arthroplasty with cement  were followed for a minimum of thirty years . Twenty-seven patients ( thirty-four [ 10.3 % ] of the hips in the initial study group ) were alive at a minimum of thirty years postoperatively . These patients served as the focus of the present study .  Revision because of aseptic loosening of the acetabular component was performed in 7.3 % ( twenty-three ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 26 % ( eight ) of the hips in the living cohort .  Revision  because of aseptic loosening of the femoral component was performed in 3.2 % ( ten ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 10 % ( three ) of the hips in the living patients . Since the twenty-five-year review , three hips were revised ( one because of acetabular loosening , one because of femoral loosening , and one because of instability ) . This end- result study demonstrated the remarkable durability of cemented Charnley total hip replacements over a span of three decades , with 88 % of the original prostheses intact at the time of the final follow-up or at the patient 's death One hundred two patients with 131 consecutive cementless total knee arthroplasties that retained the posterior cruciate ligament were followed up prospect ively . The average age of the patients was 58 years ( range , 32–75 years ) . The mean followup on the surviving knee arthroplasties was 11 years ( range , 7–16 years ) . The patellar component was metal-backed in the first 112 ( 85 % ) knees , cementless all-polyethylene in the last 17 ( 13 % ) knees , and two knees had a prior patellectomy . Forty-four metal-backed patellar components ( 48 % ) were revised ; nine were loose , and 35 had polyethylene wear through . Thirteen femoral components ( 12 % ) were revised because of femoral abrasion from a failed metal-backed patellar component . No other femoral component was revised , loose , or had osteolysis develop . Nine ( 8 % ) tibial components had failure of ingrowth ; eight have been revised . Partial radiolucencies occurred in 53 % of the tibias . Thirteen ( 12 % ) small osteolytic lesions developed , all around screws or screw holes in the tibial components . At an average of 11 years followup , cementless fixation yielded mixed results : cementless femoral fixation was excellent and metal-backed patellar components had a 48 % patellar revision rate . Cementless tibial components had an 8 % aseptic loosening rate and a 12 % incidence of small osteolytic lesions . Based on these results , the authors have ab and oned cementless fixation in total knee arthroplasty The most common reasons for revision of unicompartmental knee arthroplasty ( UKA ) are loosening and pain . Cementless components may reduce the revision rate . The aim of this study was to compare the fixation and clinical outcome of cementless and cemented Oxford UKAs .  A total of 43 patients were r and omised to receive either a cemented or a cementless Oxford UKA and were followed for two years with radiostereometric analysis ( RSA ) , radiographs aligned with the bone-implant interfaces and clinical scores . The femoral components migrated significantly during the first year ( mean 0.2 mm ) but not during the second . There was no significant difference in the extent of migration between cemented and cementless femoral components in either the first or the second year . In the first year the cementless tibial components  subsided significantly more than the cemented components ( mean 0.28 mm ( sd 0.17 ) vs. 0.09 mm ( sd 0.19 mm ) ) . In the second year , although there was a small amount of subsidence ( mean 0.05 mm ) there was no significant difference ( p = 0.92 ) between cemented and cementless tibial components . There were no femoral radiolucencies . Tibial radiolucencies were narrow ( < 1 mm ) and were significantly ( p = 0.02 ) less common with cementless ( 6 of 21 ) than cemented ( 13 of 21 ) components at two years . There were no complete radiolucencies with cementless components , whereas five of 21 ( 24 % ) cemented components had complete radiolucencies . The clinical scores at two years were not significantly different ( p = 0.20 ) . As second-year migration is predictive of subsequent loosening , and as radiolucency is suggestive of reduced implant-bone contact , these data suggest that fixation of the cementless components is at least as good as , if not better than , that of cemented devices Sixty-two knees ( 60 patients ) were r and omized to four noncemented groups . In Groups 1 , 3 , and 4 , the bone cuts were made with a cooled saw blade . In Group 1 , 15 patients were operated on with the porous coated Osteonic 7000 tibial component . In Group 2 , 15 patients were operated on with the same tibial component as in Group 1 but with the use of a st and ard saw blade . In Group 3 , 16 patients were operated on with the hydroxyapatite-coated Osteonic tibial component , and in Group 4 , 16 patients were operated on with the hydroxyapatite Duracon tibial component . All patients were followed up clinical ly and with roentgenstereometric analysis . There were no differences among the groups regarding clinical outcome . One knee was revised ( Group 2 ) after 1 year because of loosening of the tibial component . The maximum migration at 1 year was 1.7 mm in Group 1 , 1.9 mm in Group 2 , 1.3 mm in Group 3 , and 1 mm in Group 4 . At the 2-year followup , the migrations were 1.8 mm , 1.5 mm , 1.4 mm , and 1 mm in Groups 1 , 2 , 3 , and 4 , respectively . The inducible displacement that occurred at 1 year was 0.6 mm in Group 1 , 0.5 mm in Group 2 , 0.4 mm in Group 3 , and 0.4 mm in Group 4 . The hydroxyapatite coating had a strong positive effect on the tibial component fixation . No prosthesis in the hydroxyapatite groups showed continuous migration We performed this investigation to determine the possible migration starting immediately after surgery and the effect of different weightbearing regimens on the migration pattern of an uncemented hip stem ( CLS ) . Stem migration was determined with radiostereometry analysis with baseline when the patients still were anesthetized . Subsequent examinations were done up to 1 year . Twenty-nine patients ( mean age , 55 years ; range , 26 - 63 years ) were r and omized to either unrestricted weightbearing combined with intensive physiotherapy  from the first day after surgery or to partial weightbearing and a conservative training regimen for the first 3 months after surgery . At 1 week , subsidence was −0.03 mm in the unrestricted weightbearing group and 0.01 mm in the partial weightbearing group . At 1 year , subsidence was 1.01 mm in the unrestricted weightbearing group and 0.51 mm in the partial weightbearing group . One patient in the unrestricted weightbearing group had revision surgery because of aseptic loosening at 1.5 years after surgery . The CLS stem did not have any migration from the end the surgery until 1 week , but there was small migration from 1 week to 3 months after which the stem remained stable . The degree of early weightbearing did not affect the migration pattern . Level of Evidence : Level I , therapeutic study ( r and omized study ) . See the Guidelines for Authors for a complete description of levels of evidence We studied the effect of a layer of cement placed under the tibial component of Freeman-Samuelson total knee prostheses  with a metal back and an 80 mm intramedullary stem , using roentgen stereophotogrammetry to measure the migration of the tibial component during one year in 13 uncemented and 16 cemented knees . The addition of cement produced a significant reduction in migration at one year , from a mean of 1.5 mm to one of 0.5 mm ( p less than 0.01 ) , including a significant reduction in pure subsidence . One year postoperatively the clinical results were similar between the groups , but , at three years , one uncemented knee had required revision Interest in mobile-bearing total ankle arthroplasty has increased in recent years . Clinical studies show favorable but varying results , with survival rates between 70 % and 90 % at 10-year followup . Design -specific differences in early migration patterns might explain variations in the results and modes of failure . Using radiostereometric analysis ( RSA ) we prospect ively followed 15 RA patients with a cementless mobile-bearing total ankle arthroplasty .  The American Orthopaedic Foot and Ankle Society ankle score and radiostereometric radiographs  were evaluated immediately postoperatively , 6 weeks postoperatively , 3 months , 6 months , and 12 months postoperatively and yearly thereafter . The postoperative clinical results improved . We observed increased migration of the tibial component during the first 3 months , but this stabilized by the 6 month followup . The mean lateral-medial migration was 0.8 mm , distal-proximal migration was 0.9 mm , and posteroanterior migration was −0.5 mm . The latter implies the total result ant migration was in anterior and valgus tilting of this tibial component . However , migration stabilized at 6 months postoperatively . We believe the surgical technique ( anterior cortical window for placement ) and the method of tibial fixation likely explain this migration . Level of Evidence : Therapeutic , Level IV . See Guidelines for Authors for a complete description of levels of evidence Background Polyethylene ( PE ) wear particles are believed to cause aseptic loosening and thereby impair function in hip arthroplasty .  Highly crosslinked polyethylene ( XLPE ) has low short- and medium-term wear rates . However , the long-term wear characteristics are unknown and it is unclear whether reduced wear particle burden improves function and survival of cemented hip arthroplasty . Questions / purpose sWe asked whether XLPE wear rates remain low up to 10 years and whether this leads to improved implant fixation , periprosthetic bone quality , and clinical function compared to conventional PE . Methods We r and omized 60 patients ( 61 hips ) to receive either PE or XLPE cemented cups combined with a cemented stem .  At 10 years postoperatively , 51 patients ( 52 hips ) were evaluated for polyethylene wear and component migration estimation by radiostereometry , for radiolucent lines , bone densitometry , and Harris hip and pain scores . Revisions were recorded . Results XLPE cups had a lower mean three-dimensional wear rate between 2 and 10 years compared to conventional PE hips : 0.005 mm/year versus 0.056 mm/year . We found no differences in cup migration , bone mineral density , radiolucencies , functional scores , and revision rate . There was a trend toward improved stem fixation in the XLPE group . The overall stem failure rate was comparably high , without influencing wear rate in XLPE hips . Conclusions XLPE displayed a low wear rate up to 10 years when used in cemented THA , but we found no clear benefits in any other parameters . Further research is needed to determine whether cemented THA design s with XLPE are less prone to stem loosening . Level of Evidence Level I , therapeutic study . See the Instructions for Authors for a complete description of levels of evidence Systematic review s , a cornerstone of evidence -based medicine , are not produced quickly enough to support clinical practice . The cost of production , availability of the requisite expertise and timeliness are often quoted as major contributors for the delay . This detailed survey of the state of the art of information systems design ed to support or automate individual tasks in the systematic review , and in particular systematic review s of r and omized controlled clinical trials , reveals trends that see the convergence of several parallel research projects . We surveyed literature describing informatics systems that support or automate the processes of systematic review or each of the tasks of the systematic review . Several projects focus on automating , simplifying and /or streamlining specific tasks of the systematic review . Some tasks are already fully automated while others are still largely manual . In this review , we describe each task and the effect that its automation would have on the entire systematic review process , summarize the existing information system support for each task , and highlight where further research is needed for realizing automation for the task . Integration of the systems that automate systematic review tasks may lead to a revised systematic review workflow . We envisage the optimized workflow will lead to system in which each systematic review is described as a computer program that automatically retrieves relevant trials , appraises them , extracts and synthesizes data , evaluates the risk of bias , performs meta- analysis calculations , and produces a report in real time Background Bioactive coating of uncemented  total knee arthroplasty ( TKA ) is believed to increase bone ingrowth and enhance early fixation of the TKA . In a prospect i ve r and omized study using radiostereometric analysis ( RSA ) we examined migrations of the tibial implant , in an uncemented TKA with and without bioactive coating . The study was performed according to new RSA guidelines , and focus was put on some important method ological issues . Material s and methods Twenty-three patients with osteoarthrosis of the knee received an uncemented Duracon TKA either with bioactive ( hydroxyapatite or periapatite ) coating ( + HA ) or without bioactive coating ( −HA ) . Patients had RSA examinations postoperatively and at 3 , 6 and 12 months . Nine patients were excluded during the study result ing in 14 knees for final analysis . Results At 12 months follow-up we found no significant differences in migrations between the two groups . However , in general the −HA group migrated more than the + HA group , and we found a significant larger variation in migration pattern in the −HA group . In the + HA group the tibia component stabilized after 6 months , whereas the −HA group showed continuous migration . Subsidence and posterior tilt were the main migration patterns in both groups . Conclusions Bioactive coating of TKA seems to enhance early stabilization of the tibia component . Similar results are found in previous studies Few published reports have been published regarding a comparison of the long-term outcomes between mobile- ( MB ) and fixed-bearing component design s for knee arthroplasty . The minimum 10-year clinical and radiologic follow-up of an unselected consecutive series of 89 patients ( 107 knees ) who were r and omized to have one of these different design s for primary arthroplasty was done . Twenty-six patients ( 30 knees ) who had a fixed-bearing design and 24 patients ( 33 knees ) who had an MB prosthesis were available for follow-up . Two MB knees were revised for aseptic loosening of a tibial component in one and femoral component fracture in the other . In patients who did not have revision surgery , there were no differences between the groups with respect to mean Knee Society scores , knee flexion , or pain scores The  fixation of tibial components r and omized to insertion with or without cement in  twenty-six knees was examined for inducible displacement at six weeks and one year postoperatively with use of roentgen stereophotogrammetric analysis . Furthermore , migration was studied during the first two postoperative years . Inducible displacement was found in all knees at both the six-week and the one-year follow-up examination , but no differences were detected with respect to the type of fixation ( p > 0.05 ) . All tibial components  migrated for as long as one year postoperatively , after which most stabilized . No difference was found between the groups with respect to migration during the first two years postoperatively ( p > 0.05 ) , with the exception of subsidence of the component , which was found to be 0.0 ± 0.1 millimeter ( mean and st and ard error of the mean ) for the components inserted with cement and 0.5 ± 0.1 millimeter for the components inserted without cement ( p < 0.01 ) . Migration after one year was the same for both groups . We found a relationship between inducible displacement at six weeks and at one year as well as one between inducible displacement and migration at one year . To our knowledge , the present study is the first in which the micromotion of an interference-fit prosthesis was found to be similar to that of a device inserted with cement . The results of the present study emphasize the importance of the initial prosthetic fixation The Unispacer knee system is a cobalt-chrome self-centring tibial hemiarthroplasty device for use in the treatment of isolated medial compartment osteoarthritis of the knee . The indications for use are similar to those for high tibial osteotomy , but insertion does not require bone cuts or component fixation , and does not compromise future knee replacement surgery . A prospect i ve study of a consecutive series of 18 patients treated with the Unispacer between June 2003 and August 2004 was carried out to determine the early clinical results of this device . The mean age of the patients was 49 years ( 40 to 57 ) . A total of eight patients ( 44 % ) required revision within two years . In two patients revision to a larger spacer was required , and in six conversion to either a unicompartmental or total knee replacement was needed . At the most recent review 12 patients ( 66.7 % ) had a Unispacer remaining in situ . The mean modified visual analogue score for these patients at a mean follow-up of 19 months ( 12 to 26 ) was 3.0 ( 0 to 11.5 ) . The mean pain level was 30 % that of the mean pre-operative level of 10 . The early clinical results using this device have been disappointing . This study demonstrates that use of the Unispacer in isolated medial compartment osteoarthritis is associated with a high rate of revision surgery and provides unpredictable relief of pain The Oxford mobile-bearing unicompartmental knee replacement ( UKR )  is an effective and safe treatment for  osteoarthritis of the medial compartment . The results in the lateral compartment have been disappointing due to a high early rate of dislocation of the bearing . A series using a newly design ed domed tibial component is reported . The first 50 consecutive domed lateral Oxford UKRs in 50 patients with a mean follow-up of three years ( 2.0 to 4.3 ) were included .  Clinical scores were obtained prospect ively and Kaplan-Meier survival analysis was performed for different endpoints . Radiological variables related to the position and alignment of the components were measured . One patient died and none was lost to follow-up . The cumulative incidence of dislocation was 6.2 % ( 95 % confidence interval ( CI ) 2.0 to 17.9 ) at three years . Survival using revision for any reason and aseptic revision was 94 % ( 95 % CI 82 to 98 ) and 96 % ( 95 % CI 85 to 99 ) at three years , respectively . Outcome scores , visual analogue scale for pain and maximum knee flexion showed a significant improvement ( p < 0.001 ) . The mean Oxford knee score was 43 ( SD 5.3 ) , the mean Objective American Knee Society score was 91 ( SD 13.9 ) and the mean Functional American Knee Society score was 90 ( SD 17.5 ) . The mean maximum flexion was 127 ° ( 90 ° to 145 ° ) . Significant elevation of the lateral joint line as measured by the proximal tibial varus angle ( p = 0.04 ) was evident in the dislocation group when compared with the non-dislocation group . Clinical results are excellent and short-term survival has improved when compared with earlier series . The risk of dislocation remains higher using a mobile-bearing UKR in the lateral compartment when compared with the medial compartment . Patients should be informed about this complication . To avoid dislocations , care must be taken not to elevate the lateral joint line Between May 2001 and May 2003 , 233 consecutive Preservation unicompartmental knee replacements ( UKR ) were performed . Of these , 30 were lateral UKRs ( 13 % ) performed in 12 men and 16 women ( 2 bilateral cases ) with a mean age of 67 years ( range 36–93 years ) . A metal-backed mobile bearing tibial component was used in 13 knees and an all-polyethylene fixed bearing tibial component in 17 knees . The patients were review ed prospect ively at 1 and 2 years . The 2 year results show no difference in range of motion or function between the mobile and fixed bearing versions of the Preservation knee when used on the lateral side . There were three early revisions , all in the mobile bearing group Systematic review s ( SRs ) are an increasingly popular evidence -based tool and are often used to answer complex research questions across many different research domains . Early SR methodology was advanced by social scientists , and the term meta- analysis was coined by a social scientist who also conducted research in psychology . SRs have recently become popular in healthcare and are likely to be beneficial in any field . The aim of this report is to highlight issues in SR conduct with a focus on the field of nutrition and to make recommendations on improving SR conduct in this area . Development of the research question is probably the most important step in conducting an SR . The 4 main components of an answerable question are 1 ) the patient , population , or problem ; 2 ) the intervention , independent variable , or exposure ; 3 ) the comparators ; and 4 ) the dependent variables or outcomes of interest . The question will be used to determine the optimal methods for conducting the SR . SRs often include study design s beyond r and omized trials and do not always include a meta- analysis of the results . Other topics explored include underst and ing and interpreting discordant review s and the importance of reporting tools [ eg , QUality Of Reporting Of Meta-analyses ( QUOROM Statement ) or CONsoli date d St and ards Of Reporting of Trials ( CONSORT Statement ) ] . Recommendations are then provided , such as developing a capacity-building program , search ing the primary literature for research gaps , and extending reporting tools such as the QUOROM Statement to the field of nutrition UNLABELLED The current study was performed to determine the status , at a minimum of twenty-five years , of a prospect i ve , single-surgeon series of patients treated with primary Charnley total hip arthroplasty with a contemporary femoral cementing technique that included use of a distal cement plug and a retro grade cement-delivery system . Since our review at a minimum of twenty years postoperatively , two primary total hip prostheses were revised ( one because of acetabular loosening , and one because of femoral loosening ) . Of the original cohort of 357 hips ( 320 patients ) , ten ( 2.8 % ) had revision of the femoral stem because of aseptic loosening . Forty-nine patients ( fifty-two hips , 14.6 % ) who had been in the initial study group were still living at the time of the present review . Five hips ( 10 % ) in living patients had required a femoral revision because of aseptic loosening . Including those that were revised , eight femoral components ( 17 % ) in living patients were seen to be loose radiographically . Although this study demonstrates the remarkable durability of the femoral fixation obtained with the polished flatback Charnley prosthesis and the contemporary cementing technique , there was some deterioration of the results with time . These results provide a st and ard for comparison with cementless fixation after hips treated with that technique have been followed for a similar duration . LEVEL OF EVIDENCE Therapeutic Level IV . See Instructions to Authors for a complete description of levels of evidence 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 Background and purpose There is no st and ard for patient triage in  total knee arthroplasty ( TKA ) based on joint functional characteristics . This is largely due to the lack of objective postoperative measurement of success in TKA in terms of function and longevity , and the lack of knowledge of preoperative metrics that influence outcome . We examined the association between the preoperative mechanical environment of the patients knee joint during gait and the post-TKA stability of the tibial component  as measured with  radiostereometric analysis ( RSA ) .  Methods 37 subjects were recruited out of a larger r and omized RSA trial .  3-dimensional gait analysis was performed in the preoperative week . Longitudinal RSA data were gathered postoperatively at 6 months and 1 year . Results We found a statistically significant association between the pattern of the knee adduction moment during gait preoperatively and the total migration of the implant at 6 months postoperatively . A substantial proportion of the variability in the total postoperative tibial component migration ( R2 = 0.45 ) was explained by a combination of implant type , preoperative knee joint loading patterns during gait , and body mass index at 6 months postoperatively . The relationships did not remain statistically significant at 1 year postoperatively . Interpretation Our findings support the hypothesis that preoperative functional characteristics of patients , and particularly joint loading patterns during activities of daily living , are important for outcome in TKA . This represents a first step in the development of predictive models of objective TKA outcome based on preoperative patient characteristics , which may lead to better treatment strategies . Clinical Trials.gov ( NCT00405379 Background : The Bisurface knee prosthesis was design ed in 1989 to improve knee flexion without affecting the durability of the prosthesis . The prosthesis has a unique ball- and -socket joint in the midposterior portion of the femoral and tibial components , which functions as a posterior stabilizing cam mechanism and causes femoral rollback . The femoral component was made of alumina ceramic . The purpose of this study was to review the clinical results of the first 223 arthroplasties performed with this prosthesis in order to assess whether this new implant had achieved its design objectives . Methods : From December 1989 to May 1994 , all patients who were scheduled for primary total knee arthroplasty were enrolled in a prospect i ve study of the Bisurface knee . The patients were evaluated clinical ly according to The Hospital for Special Surgery knee-rating system and with a self-administered question naire , and they were evaluated radiographically according to the system of the Knee Society . Kaplan-Meier survivorship analysis was performed with revision of the knee or recommendation for revision as the end point . Results : One hundred and sixty-six patients treated with a total of 223 consecutive primary total knee arthroplasties were enrolled in the study , and 182 knees were followed for 3.9 to 9.0 years ( mean , 5.8 years ) . Preoperatively , the mean Hospital for Special Surgery knee score was 44.5 points . At the time of latest follow-up , the mean knee score was 86.3 points . The mean preoperative and postoperative ranges of flexion were 119 and 124 degrees , respectively . The patients , even those with a good preoperative range of motion , rarely lost deep flexion of the knee after the procedure . A revision operation was performed in eight knees ( because of infection in five , instability in two , and breakage of the peg of the patellar component in one ) . Two knees had recurrent medial-lateral subluxations of the femorotibial articulation , which were treated nonoperatively . No prosthesis had loosened aseptically and no alumina ceramic femoral component had broken by the time of latest follow-up . The rate of survival of the implant was 94 percent ( 95 percent confidence interval , 90 to 98 percent ) at six years . According to the patient question naires , 20 percent of the knees sometimes felt loose in daily living activities , which prompted us to improve the intrinsic stability of the prosthesis by improving the congruity of the ball- and -socket joint . Conclusions : Total knee arthroplasty with the Bisurface prosthesis result ed in an excellent range of motion and a high level of satisfaction with the operation ; the durability of the prosthesis is promising We aim ed to determine whether not using a tourniquet in cemented TKA would affect migration of the tibial component measured by radiosterometric analysis ( RSA ) . Seventy patients were r and omized into a tourniquet group and a non-tourniquet group and using model-based RSA , the migration of the tibial component was analyzed . Primary and secondary outcome measures were maximum total point motion ( MTPM ) and translations and rotations . Follow-up period was 2 years . The tibial component was well fixated in both groups and no significant difference in migration between the two groups was detected ( P=0.632 ) . Mean MTPM ( SD ) was 0.47 mm ( 0.16 ) in the tourniquet group and 0.45 mm ( 0.21 ) in the non-tourniquet group . Absence of tourniquet indicates that stable fixation of the tibial component can be achieved in cemented TKA Background and purpose We performed a r and omized study to determine the migration patterns of the Spectron EF femoral stem and to compare them with those of the Charnley stem , which is regarded by many as the gold st and ard for comparison of implants due to its extensive documentation . Patients and methods 150 patients with a mean age of 70 years were r and omized , single-blinded , to receive either a cemented Charnley flanged 40 monoblock , stainless steel , vaquasheen surface femoral stem with a 22.2-mm head ( n = 30 ) or a cemented Spectron EF modular , matte , straight , collared , cobalt-chrome femoral stem with a 28-mm femoral head and a roughened proximal third of the stem ( n = 120 ) . The patients were followed with repeated radiostereometric analysis for 2 years to assess migration . Results At 2 years , stem retroversion was 2.3 ° and 0.7 ° ( p < 0.001 ) and posterior translation was 0.44 mm and 0.17 mm ( p = 0.002 ) for the Charnley group ( n = 26 ) and the Spectron EF group ( n = 74 ) , respectively . Subsidence was 0.26 mm for the Charnley and 0.20 mm for the Spectron EF ( p = 0.5 ) . Interpretation The Spectron EF femoral stem was more stable than the Charnley flanged 40 stem in our study when evaluated at 2 years . In a report from the Norwegian arthroplasty register , the Spectron EF stem had a higher revision rate due to aseptic loosening beyond 5 years than the Charnley . Initial stability is not invariably related to good long-term results . Our results emphasize the importance of prospect i ve long-term follow-up of prosthetic implants in clinical trials and national registries and a stepwise introduction of implants Background : Use of modern cementing techniques for fixation of femoral components in total hip arthroplasty has had excellent clinical and radiographic results in most patients . However , several authors have described early loosening of femoral components with roughened and precoated finishes . The purpose of this study was to examine the performance of the precoated Iowa stem , which has increased offset , and to compare the results with those of another cemented precoated femoral component with st and ard offset used at our institution . Methods : We carried out a prospect i ve analysis of 102 primary hybrid total hip arthroplasties ( a cementless acetabular component and a cemented femoral component ) performed with use of the Iowa femoral component in ninety-five patients at our institution . The Iowa stem was used in hips that required greater offset than is available with st and ard stems as determined by preoperative templating . The average age of the patients at the time of the index procedure was sixty-nine years . Sixteen patients ( seventeen hips ) died before the forty-eight-month minimum follow-up period had elapsed . Two patients were lost to follow-up , and radiographic follow-up was incomplete for one . The mean duration of clinical and radiographic follow-up of the remaining eighty-two hips in the seventy-six surviving patients was sixty-five months ( range , forty-eight to 104 months ) . Results : The average preoperative Harris hip score of 47 points ( range , 16 to 69 points ) improved to an average of 87 points ( range , 24 to 100 points ) at the time of the review . Two hips underwent femoral component revision . Four femoral stems were radiographically loose at an average of thirty-four months . Femoral osteolysis was seen in five hips ( 6 percent ) at an average of fifty-four months postoperatively . No acetabular component was revised because of aseptic loosening . According to Kaplan-Meier analysis , the seven-year survival rate , with an end point of femoral revision , osteolysis , or stem debonding , was 90.6 percent ( 95 percent confidence interval , 0.87 to 0.94 ) . Conclusions : The prevalence of revision , osteolysis , and loosening after total hip arthroplasty with the  Iowa femoral component  at our institution was higher than that seen in our series of Harris Precoat stems , which had a survival rate of 98.4 percent ( 95 percent confidence interval , 0.97 to 1.00 ) at ten years with the same end points . The design of the Iowa stem may make it difficult to achieve a good cement mantle , and , in combination with the geometry and increased offset of the stem , may compromise the long-term survival of this cemented femoral component Evidence -based medicine represents the combination of the best available clinical research evidence with clinical experience and expertise and the needs and expectations of patients . Evidence -based medicine as a concept has been available for years , but it has become increasingly important over the last decade . Some evidence has suggested that it began as early as the ancient Chinese medicine practice s , while other evidence has indicated its origins were in postrevolutionary France with the systematic patient observations of Pierre Louis1 . Gordon Guyatt led a group at McMaster University in the early 1990s that introduced many of the current concepts of evidence -based medicine . This led to a major increase in interest in the area . One paper had been published in the literature in 1992 , but by 1998 over a thous and manuscripts had been published in the field1 . Evidence -based medicine utilizes the best available research evidence . In the hierarchy of medical evidence , systematic review s including meta-analyses represent the highest form of evidence if inclusion is limited to Level-I or II studies ( Table I ) . Systematic review s of Level-III or IV observational studies can be performed , but they represent Level-III or IV evidence . Frequently , in orthopaedics , systematic review s or meta-analyses may not be available and clinicians may need to rely upon r and omized controlled trials , cohorts , case-control studies , case series , or , in some areas , expert opinion . Orthopaedists may not yet recognize this hierarchy . During the 2005 Annual Meeting of the American Orthopaedic Association ( AOA ) , the audience was asked the question : “ Findings from which type of study design are most likely to influence your clinical practice ? ” The responses indicated that a r and omized controlled study design was used by 49 % ; a systematic review and /or meta- analysis of Level-I studies , by 44 % ; expert opinion , by 5 % ; and case series , by 3 % . View this table : TABLE I Medical Evidence Hierarchy At a symposium
INTERPRETATION There was a clinical ly relevant association between early migration of TKPs and late revision for loosening .
PURPOSE We performed two parallel systematic review s and meta-analyses to determine the association between early migration of tibial components and late aseptic revision .