title: A randomised RSA study of Peri-Apatite HA coating of a total knee prosthesis. Postoperative clodronate decreases prosthetic migration: 4–year follow-up of a randomized radiostereometric study of 50 total knee patients Hydroxyapatite augmentation of the porous coating improves fixation of tibial components. A randomised RSA study in 116 patients. Hydroxyapatite-Enhanced Tibial Prosthetic Fixation The effect of Palamed® G bone cement on early migration of tibial components in total knee arthroplasty Periapatite May Not Improve Micromotion of Knee Prostheses in Rheumatoid Arthritis No surgical innovation without evaluation: the IDEAL recommendations Uncemented HA-coated Implant is the Optimum Fixation for TKA in the Young Patient 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 Five- to 8-year results of the uncemented Duracon total knee arthroplasty system. Local peroperative treatment with a bisphosphonate improves the fixation of total knee prostheses: A randomized, double-blind radiostereometric study of 50 patients Flat vs. concave tibial joint surface in total knee arthroplasty: Randomized evaluation of 39 cases using radiostereometry Inferior performance of Boneloc bone cement in total knee arthroplasty: a prospective randomized study comparing Boneloc with Palacos using radiostereometry (RSA) in 19 patients. The Effect of Hydroxyapatite on the Micromotion of Total Knee Prostheses. A Prospective, Randomized, Double-Blind Study* Problems With Cementless Total Knee Arthroplasty at 11 Years Followup Resurfacing versus not resurfacing the patella in total knee arthroplasty: 8- to 10-year results. Five-year results of the Sigma total knee arthroplasty. Patellar resurfacing in total knee replacement: a ten-year randomised prospective trial. The Outcome of the Cementless Tibial Component: A Minimum 14-Year Clinical Evaluation Kinematic total knee arthroplasty: a 10- to 14-year prospective follow-up review. Should we reconsider all-polyethylene tibial implants in total knee replacement? Proximally cemented versus uncemented Freeman-Samuelson knee arthroplasty. A prospective randomised study. Evaluation of micromotion in cemented vs uncemented knee arthroplasty in osteoarthrosis and rheumatoid arthritis. Randomized study using roentgen stereophotogrammetric analysis. Early Inducible Displacement of Tibial Components in Total Knee Prostheses Inserted with and without Cement. A Randomized Study with Roentgen Stereophotogrammetric Analysis* [What effect does the hydroxyapatite coating have in cementless knee arthroplasty?]. Total knee replacement with and without patellar resurfacing: a prospective, randomised trial using the profix total knee system. Impact of modern technique on long-term results of total condylar knee arthroplasty. Clinical results of the modular porous-coated anatomic (PCA) total knee arthroplasty with cement: a 5-year prospective study. Fixation of the tibial component using CMW-1 or Palacos bone cement with gentamicin: Similar outcome in a randomized radiostereometric study of 51 total knee arthroplasties Mobile Bearings Do Not Improve Fixation in Cemented Total Knee Arthroplasty Increased varus-valgus tilting of screw-fixated knee prostheses. Stereoradiographic study of uncemented versus cemented tibial components. The Johnson-Elloy (Accord) total knee replacement. Poor results at 8 to 12 years. Survival analysis of cemented Press-Fit Condylar total knee arthroplasty. Introducing new technology: a stepwise algorithm. The stability of three different cementless tibial components. A randomized radiostereometric study in 45 knee arthroplasty patients. Does early micromotion of femoral stem prostheses matter? 4-7-year stereoradiographic follow-up of 84 cemented prostheses. VersaBond bone cement prospective randomized study of the clinical properties of a new bone cement in total knee replacement. Long-term results of Kinematic Condylar knee replacement. An analysis of 404 knees.
abstract: BACKGROUND In total knee replacement , sound early fixation of the prosthesis is crucial for achieving a good long-term result and for minimising the risk of loosening . Various types of prosthetic material , different surface textures and shapes and the incorporation of screws or pegs have been used to achieve good fixation , particularly in the uncemented knee . Hydroxyapatite ( HA ) coating of prosthetic joint components is another technique used to enhance early stability and so to improve the longevity of the prosthesis-bone fixation . HA ceramic coatings are mostly plasma sprayed onto the fixation surface of the implant . Plasma spraying is largely a ' line of sight ' technique and as such there are difficulties involved when covering three-dimensional planes , such as porous beaded fixation surfaces typically found on several knee prostheses . The objective of this study was to assess the clinical performance of the solution-deposited HA coating , Peri-Apatite , with regard to its ability to stimulate an endurable and stable implant fixation . PATIENTS AND METHODS We r and omised 60 patients into two groups ; one group received the porous coated prosthesis with solution-deposited HA  , and the other group received a prosthesis without HA . Radiostereometric examination was used as the primary tool for measuring migration in the prosthetic components . RESULTS There was a lower incidence of early subsidence in the Peri-Apatite group . At 24 months there were no differences in clinical scorings or maximal total point motion . CONCLUSION Addition of solution-deposited HA coating appears to provide better early stable fixation in a porous coated knee prosthesis Background We have previously reported that 6 months of oral treatment with clodronate reduced the migration of the NexGen total knee prosthesis during the first postoperative year , as measured by  radiostereometry ( RSA ) . We now report the 4-year results . Methods This was a double-blind r and omized study , using RSA with maximal total point motion ( MTPM ) . Results With analysis according to the “ intention to treat ” principle , the only remaining difference between the groups at 4 years was reduced rotation around the transverse axis ( a secondary variable ) in the clodronate group . However , 3 patients ( all clodronate )  did not take any tablet after surgery . If they are excluded , there was an almost statistically significant difference between the groups at 4 years regarding MTPM from baseline , with the clodronate group showing 25 % less migration . From 1 to 4 years , there was no difference in migration rate by MTPM , but there was a continuous increase in rotation around the transverse axis in the controls , which differed from the clodronate group . There were no cases of aseptic loosening . 2 patients had migration of more than 1.3 mm from baseline to 4 years ; neither of them had taken clodronate . The others had migration of less than 0.9 mm . Interpretation Because migration was clearly reduced by clodronate during the first postoperative year , and there was still a difference at 4 years when analyzed per protocol , it appears likely that this treatment can diminish the risk of loosening . The difference in the number of outliers also points in this direction , and may be more relevant than mean migration values In a single-blind , r and omised series of knee replacements in 116 patients , we used radiostereometric analysis ( RSA ) to measure micromotion in three types of tibial implant fixation for two years after knee replacement . We compared hydroxyapatite-augmented porous coating , porous coating , and cemented fixation of the same design of tibial component . At one to two years , porous-coated implants  migrated at a statistically significantly higher rate than hydroxyapatite-augmented or cemented implants . There was no significant difference between hydroxyapatite-coated and cemented implants . We conclude that hydroxyapatite augmentation may offer a clinical ly relevant advantage over a simple porous coating for tibial component fixation , but is no better than cemented fixation 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 Abstract Objective : Migration of the tibial component in total knee arthroplasty ( TKA ) is subject of many studies using roentgen stereophotogrammetric analysis ( RSA ) . In previous studies of cemented and uncemented tibial components , high migration values were found . Improvements in cementing technique , prosthetic design and pre-coating techniques reduced these values as shown in more recent studies . Material and subjects : A total of 35 patients were initially included in the study and operated on between 12/1999 and 10/2000 . All patients received a NexGen ® TKA cemented into the proximal tibia using Palamed ® G bone cement . The implants and the tibial metaphysis were marked with st and ard tantalum markers . Radiostereometric analysis was performed post-operatively and after 3 , 6 and 12 months using a st and ard digital radiostereometric analysis . Functional parameters were assessed using the Knee Society Score ( KSS ) clinical rating system . Results : There were no complications and failures within the first year . After 1 year radiostereometric measurements of the translational parameters along and the rotational parameters around the x- , y- and z-axis revealed : X-Trans –0.19 mm , Y-Trans + 0.02 mm , Z-Trans + 0.08 mm , X-Rot + 0.26 ° , Y-Rot –0.35 ° , Z-Rot + 0.09 ° . The maximum total point motion was + 0.96 mm and the mean maximum subsidence was –0.23 mm . Except for anterior-posterior , medio-lateral stability and extension leg all endpoints of the KSS clinical rating system showed a significant improvement . Conclusions : After 12 months , the use of Palamed ® G bone cement in total knee arthroplasty was demonstrated to be safe . Both the clinical and radiostereometric results were good and comparable to the results reported in other RSA studies in cemented total knee arthroplasty Prosthesis migration in bone inevitably occurs in cemented and uncemented total knee arthroplasty tibial components . Cemented design s as the gold st and ard give immediate fixation whereas cementless design s need a period of bone ingrowth onto the surface irregularities of the implants . The addition of bioactive coatings may enhance this process of ingrowth . A controlled r and omized prospect i ve RSA study was carried out on 26 Duracon implants in a rheumatoid arthritis patient group to evaluate the effect of a periapatite coating on the fixation of the tibial tray . The coated and the noncoated groups were matched for sex , age , body mass index , and HSS Knee Score . Stage of preoperative joint destruction and preoperative and postoperative mechanical leg axis showed no differences . We saw no differences in migration between the two groups , but a trend for lesser translations along and rotations about all three axes in the periapatite group . The periapatite-coated components showed a lower variance in subsidence than did the uncoated components . Both groups also showed a high variance in anterior tilting of the components . The cementless PA-coated Duracon prosthesis used in patients with RA may provide improved fixation of tibial components although we could not demonstrate improvement in this small controlled series . Level of Evidence : Therapeutic Level II . See the Guidelines for Authors for a complete description of levels of evidence 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 Fixation of the tibial component in total knee arthroplasty in younger patients remains controversial . We evaluate the results of three different types of fixation of the Profix total knee arthroplasty  in a r and omized controlled trial of 97 consecutive knees ( 85 patients ) with osteoarthrosis or inflammatory arthritis with 2-year followup of all patients . We r and omized patients to three different types of fixation of the tibial component : cemented , uncemented ( HA coated ) with screws , or uncemented ( HA coated ) without screws . We performed clinical evaluations and radiostereometric analysis at 6 weeks , and 3 , 6 , 12 and 24 months postoperatively . The knees in the uncemented groups migrated more than those in the cemented group during the first 3 months , but at 2 years we observed no differences . The uncemented implants  displayed all migration within the first 3 months . The cemented implants did not stabilize but had continuously increasing migration during the followup . Cementless implants without screws  did not migrate more than implants with screws and displayed similar pattern of migration , indicating screws do not improve fixation .  Uncemented fixation using hydroxyapatite-coated implants without screws seems to be the best solution for the younger patient . Level of Evidence : Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence 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 We report prospect i ve clinical and radiographic outcomes of a series of 219 hydroxyapatite-coated Duracon ( Stryker Howmedica Osteonics Corporation , Kalamazoo , Mich ) total knee arthroplasties with a follow-up of 5 to 8 years .  Knee Society Score , Western Ontario and McMaster Universities Osteoarthritis index ( WOMAC ) , and SF-12 Health Status Question naire were used . Analysis of fluoroscopic radiographs was performed with the American Knee Society Score .  All living patients ( 186 knees ) were followed up . Twenty-eight patients ( 30 knees ) had died . The preoperative Knee Society Score of 43.8 increased to 77.1 and the preoperative Function score of 20.3 increased to 63.4 . WOMAC scores showed marked improvement ( pain , 250 preoperatively to 157 ; stiffness , 115 preoperatively to 56 ; and function , 910 preoperatively to 588 ) . There was no radiographic evidence of loosening or migration . Gaps visible at the bone-implant interface healed over the first year . Three prostheses were revised , 2 for deep infection and 1 for tibial tray subsidence . A survivorship of 98.6 % has been achieved at 8 years . This intermediate-term study with 100 % follow-up at 8 years demonstrates excellent clinical and radiographic outcomes . It is our opinion that these are comparable to the gold st and ard cemented total knee arthroplasties and may have advantages over other uncoated cementless design Background Postoperative migration of a joint prosthesis is related to the risk of late loosening . We have previously reported that oral treatment with clodronate reduced migration of the cemented NexGen total knee prosthesis during the first postoperative year , as measured by radiostereometry ( RSA ) . Oral bisphosphonate treatment is sometimes unpleasant , and local treatment will enable higher local concentrations . We now report the results of local peroperative treatment with another bisphosphonate , ib and ronate , with the same prosthesis . Methods This is a double-blind , r and omized study of 50 patients using RSA with maximal total point motion ( MTPM ) as primary effect variable . 1 mg ib and ronate ( 1 mL ) or 1 mL saline was applied to the tibial bone surface 1 min before cementation . RSA examination was done on the first postoperative day , and at 6 , 12 , and 24 months . Results One ib and ronate-treated patient died of unrelated causes , and 1 control patient refused to come for follow-up , leaving 24 patients in each group for analysis . There were no cases of aseptic loosening . By repeated measures ANOVA , migration ( MTPM ) was reduced by local application of ib and ronate ( p = 0.006 ) . The effect was most pronounced at 6 months , with a reduction from 0.45 to 0.32 mm ( 95 % CI for reduction : 0.04–0.21 mm ) . At 12 months , the migration from the postoperative examination was reduced from 0.47 to 0.36 mm ( 95 % CI for reduction : 0.02–0.20 mm ) . At 24 months , the reduction was from 0.47 to 0.40 mm ( 95 % CI : -0.01–0.16 mm ) . Interpretation This is the first study to show improvement of prosthesis fixation by local pharmacological treatment in humans . The treatment appears to be safe , cheap , and easy to perform . However , the improvement in postoperative stability was not greater than with systemic clodronate treatment 40 patients with non-inflammatory arthrosis and minor preoperative deformity ( / 5 ° ) were operated on with an AMK type ( DePuy , Johnson & Johnson ) total knee arthroplasty ( TKA ) . The posterior cruciate ligament was retained . The patients were divided into those with a flat ( terminology of the manufacturer : st and ard ) or a concave ( terminology of the manufacturer : constrained ) polyethylene insert ( 20 in each group ) .  Radiostereometric ( RSA ) examinations were done postoperatively and after 3 , 12 and 24 months . The median absolute rotations of the tibial inserts varied between 0.12 and 0.24 ( range 0.00 - 1.54 ) degrees , with no differences between the 2 groups . The median maximum totalpoint motions ( flat/concave = 0.41/0.42 mm ) , the maximum subsidence or lift-off did not differ . The Hospital for Special Surgery knee score and the patients ' opinion about the operation , based on their preoperative expectations , showed little , if any , differences . At 2 years , 10 of 20 patients with flat and 13 of 19 with concave inserts regarded their knee function as normal or almost so We compared Boneloc bone cement with conventional cement ( Palacos ) in fixating the tibial component during 2 - 5 years in 19 patients with gonarthrosis undergoing total knee arthroplasty in a prospect i ve r and omized study .  Boneloc displayed significantly larger migration , subsidence and lift-off than Palacos . The difference was identifiable already within 3 months postoperatively , but became significant at 12 months . In the Boneloc group , all components showed subsidence of the posterior part and lift-off of the anterior part of the tibial component , whereas in the Palacos group , the locations of subsidence and lift-off were evenly distributed about the edge of the implant . At 5 years , both Boneloc knees so far investigated were clinical failures with high migration rates . We conclude that , even in total knee arthroplasty , there is a substantial risk that Boneloc leads to inferior clinical results , but later than in hip replacements A prospect i ve , r and omized , double-blind study was performed to evaluate three different means of fixing tibial components  during total knee arthroplasty . Eleven components fixed with cement , ten hydroxyapatite-coated components fixed without cement  , and ten noncoated components fixed without cement were studied . A posterior cruciate ligament-retaining total condylar implant was used . Micromotion of the components was assessed with roentgen stereophotogrammetric analysis during the two-year follow-up period . There were no significant differences among the patients with regard to age ( mean [ and st and ard deviation ] , 68 ± 11.6 years ) , body-mass index ( mean , 23 ± 2.8 kilograms per square meter ) , or stage of osteoarthrosis ( mean , 4 ± 2.4 according to the classification system of Ahlbäck and 5 ± 0.6 according to that of Larsen et al. ) . The diagnosis was osteoarthrosis in five knees , and it was rheumatoid arthritis in twenty-six .  The clinical scores were similar among the study groups . According to the system of the Knee Society , the mean preoperative functional score was 10 ± 2.9 points and the mean preoperative knee score was 24 ± 3.2 points . At the two-year follow-up evaluation , these scores were 41 ± 8.3 and 79 ± 3.2 points , respectively . A significant difference with regard to micromotion was found between the noncoated components fixed without cement and the hydroxyapatite-coated components fixed without cement as well as between the noncoated components fixed without cement and the components fixed with cement ( p < 0.001 , analysis of variance ) . The hydroxyapatite-coated components fixed without cement and the components fixed with cement both had far less micromotion along the longitudinal axis ( subsidence ) throughout the follow-up period than did the noncoated components fixed without cement . At the two-year follow-up evaluation , the subsidence of the noncoated components was -0.73 ± 0.924 millimeter , the subsidence of the cemented components was -0.05 ± 0.109 millimeter , and the subsidence of the hydroxyapatite-coated components was -0.06 ± 0.169 millimeter . The cemented components as well as the hydroxyapatite-coated components also had less translation along the transverse axis ( p < 0.001 , analysis of variance ) and the sagittal axis ( p < 0.001 , analysis of variance ) compared with the noncoated components . In conclusion , micromotion of hydroxyapatite-coated tibial components fixed without cement was similar to that of tibial components fixed with cement . Therefore , hydroxyapatite , a biological mediator , may be necessary for the adequate fixation of tibial components when cement is not used 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 Patellar resurfacing in total knee arthroplasty is a topic debated in the literature . Concerns include fracture , dislocation , loosening , and extensor mechanism injury . Residual anterior knee pain has been reported when the patella is not resurfaced . One hundred patients with osteoarthritic knees were prospect ively r and omized to either have their patella resurfaced or left not resurfaced . All patients were treated with a single prosthesis that featured an anatomically design ed patellofemoral articulation ( Anatomic Medullary Knee , DePuy , Warsaw , IN ) Two patients in the unresurfaced group and one in the resurfaced group required repeat surgery for patellofemoral complications . At 8- to 10-year follow-up evaluations , Knee Society Clinical Ratings scores were not different between the 2 groups . Rates of anterior knee pain with walking and stair climbing were significantly less in the resurfaced group . Eighty percent of patients with a resurfaced patella were extremely satisfied with their total knee arthroplasty versus 48 % without patellar resurfacing . When satisfied and extremely satisfied patients were grouped together , there was no difference between the 2 groups The DePuy Sigma total knee arthroplasty ( TKA ) was introduced in 1997 as a modification of the Press Fit Condylar Knee ( PFC ) TKA and has been used extensively in the United Kingdom and worldwide . It is the most commonly used TKA in Engl and and Wales , where it accounts for 36 % of all primary TKA . The PFC was well established , with reported 10-year survival rates of 93 - 97 % , but this study reports the first 5-year clinical and radiographic follow-up data for the Sigma TKA . Over a 10-month period , 212 Sigma TKAs were performed in 180 patients . Patients were seen at a specialist nurse-led clinic 7 to 10 days before admission and at 6 months , 18 months , 3 years and 5 years after surgery . Data were recorded prospect ively at each visit . Radiographs were obtained at the 5-year follow-up appointment . Of 212 knees , 178 ( 151 patients ) were alive at 5 years . Three were lost to follow up . Six knees ( 3.0 % ) were revised , five for infection and one underwent change of polyethylene insert at 4.9 years . Five-year survival with an endpoint of revision for any reason was 97.0 % ; with an endpoint of revision for aseptic failure it was 99.5 % . The median American Knee Society knee rating score was 93 out of 100 at 5 years compared with 25 out of 100 at admission . Of 147 radiographs , none showed radiographic loosening of either component . Seventeen ( 11.6 % ) showed radiolucent lines . Twenty-eight ( 19.0 % ) had alignment outside the range of 7+/-3 degrees valgus . These results suggest that the Sigma TKA gives acceptable clinical results after 5 years . Further follow-up studies are required to see if this performance is maintained in the long term A series of 100 consecutive osteoarthritic patients was r and omised to undergo  total knee replacement using a Miller-Galante II prosthesis , with or without a cemented polyethylene patellar component .  Knee function was evaluated using the American Knee Society score , Western Ontario and McMaster University Osteoarthritis index , specific patellofemoral-related questions and radiographic evaluation until the fourth post-operative year , then via question naire until ten years post-operatively . A ten-point difference in the American Knee Society score between the two groups was considered a significant change in knee performance , with alpha and beta levels of 0.05 . The mean age of the patients in the resurfaced group was 71 years ( 53 to 88 ) and in the non-resurfaced group was 73 years ( 54 to 86 ) . After ten years 22 patients had died  , seven were suffering from dementia  , three declined further participation and ten were lost to follow-up . Two patients in the non-resurfaced group subsequently had their patellae resurfaced . In the resurfaced group one patient had an arthroscopic lateral release . There was no significant difference between the two treatment groups : both had a similar deterioration of scores with time , and no further patellofemoral complications were observed in either group . We are unable to recommend routine patellar resurfacing in osteoarthritic patients undergoing total knee replacement on the basis of our findings The long term survival of the Miller-Galante I cementless total knee arthroplasty  was evaluated by study ing prospect ively for a minimum of 14 years ( range , 14–17 years ) , 124 consecutive cementless total knee arthroplasties using a Miller-Galante I prosthesis in 99 patients with a mean age of 62 years who had primary or secondary osteoarthritis .  Knee function and roentgenograms were evaluated using the Knee Society criteria . Kaplan-Meier survivorship analysis was conducted . Five patients ( five knees ) were lost to followup ; six patients died with six knees in place . Fifteen knees ( 15 patients ) failed and were revised . Thirteen metal-backed patellas were revised . Eight of these revisions also required exchange of the femoral component , but only one tibial tray was revised . One knee ( one patient ) was revised for an infection . Of the 98 knees not revised ( 73 patients ) observed throughout this study , the average preoperative knee score was 31 ( range , 0–47 ) ; postoperatively , the average knee score was 91 ( range , 72–100 ) . The average function score improved from 28 ( range , 10–45 ) to 84 ( range , 50–100 ) . Twenty-four tibial trays ( 21 % ) and twenty femoral components ( 17 % ) of the 113 knees studied showed osteolysis . This study indicates that osteointegration of cementless tibial components can be successful with screw fixation , although there is a worrisome incidence of tibial and femoral osteolysis . The overall knee survival rate was 87 % ; however , the tibial component had a survival of 99 % To underst and better the type and incidence of long-term complications in  total knee replacement , 306 primary Kinematic total knee arthroplasties performed between June 1978 and December 1982 were prospect ively review ed in detail . The Kinematic knee is a nonconstrained , posterior cruciate-retaining prosthesis that has right and left femoral components to afford anatomic tracking of the patella . The overall revision rate was 6.5 % . The most common cause for revision surgery was patellar complications . Ten revisions ( 3.06 % ) were for patellar component loosening . Two knees were revised for patella subluxation ( 0.65 % ) ; 1 was in a resurfaced rheumatoid patella , and 1 in an unsurfaced osteoarthritic patella . Stair climbing was better with an unsurfaced patella . Anterior knee pain was 21.8 % in the unsurfaced patella and 11.2 % in the replaced patella . These data suggest patella replacement is not appropriate with this design The role of modular tibial implants in total knee replacement is not fully defined . We performed a prospect i ve r and omised controlled clinical trial using radiostereophotogrammetric analysis to compare the performance of an all-polyethylene tibia with a metal-backed cruciate-retaining condylar design , PFC-Sigma total knee replacement for up to 24 months . There were 51 patients who were r and omised into two treatment groups . There were 10 subsequent withdrawals , leaving 21 all-polyethylene and 20 metal-backed tibial implants . No patient was lost to follow-up . There were no significant demographic differences between the groups . At two years one metal-backed implant showed migration > 1 mm , but no polyethylene implant reached this level . There was a significant increase in the SF-12 and Oxford knee scores after operation in both groups . In an uncomplicated primary total knee replacement the all-polyethylene PFC-Sigma tibial prosthesis showed no statistical difference in migration from that of the metal-backed counterpart . There was no difference in the clinical results as assessed by the SF-12 , the Oxford knee score , alignment or range of movement at 24 months , although these assessment measures were not statistically powered in this study 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 Twenty-four patients ( 25 knees ) with osteoarthrosis ( OA ) and 19 patients ( 20 knees ) with rheumatoid arthritis ( RA ) were operated with bi-tricompartmental knee arthroplasty .  The patients were r and omized to cemented or cementless fixation of the tibial component . The fixation of the tibial components was examined with roentgen stereophotogrammetric analysis ( RSA ) up to 24 months after operation . The following parameters representing tibial component micromotion were measured : ( 1 ) maximum migration of the prosthetic edge ( maximum total point motion , MTPM ) ; ( 2 ) distal migration of the prosthetic center ( subsidence ) ; ( 3 ) maximum proximal movements of the prosthetic edge ( " lift-off " ) ; and ( 4 ) prosthetic rotations , corresponding to internal/external rotation , adduction/abduction , and forward/backward tilt of the tibial component . All prostheses displayed significant micromotions , which tended to decrease 3 - 6 months after the operation . The average migration after 2 years , when measured as maximum single axis rotation , and MTPM were about 0.9 degrees-1.5 degrees and 1.0 - 1.5 mm , respectively , in all four groups . There were no statistically significant differences between cemented and cementless prostheses in either the OA or the RA group . The fixation in the RA patients did not significantly differ from that of the OA patients , perhaps because the RA patients had lower weight and were living a more sedentary life 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 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 We have examined the differences in clinical outcome of  total knee replacement ( TKR ) with and without patellar resurfacing in a prospect i ve , r and omised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant . The procedures were carried out between February 1998 and November 2002 . A total of 159 TKRs in 142 patients were available for review at a mean of four years ( 3 to 7 ) . The patients and the clinical evaluator were blinded in this prospect i ve study . Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system . Specific evaluation of anterior knee pain , stair-climbing and rising from a seated to a st and ing position was also undertaken . No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes . In 22 of 73 knees ( 30.1 % ) with and 18 of 86 knees ( 20.9 % ) without patellar resurfacing there was some degree of anterior knee pain ( p = 0.183 ) . No revisions related to the patellofemoral joint were performed in either group . Only one TKR in each group underwent a re-operation related to the patellofemoral joint . A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing ( p = 0.006 ) This study reports the 14-year survivorship for 106 consecutive total condylar knee arthroplasties implanted using modern technique . All were performed by a single surgeon and have been observed prospect ively since 1979 . Failure was defined as revision for any reason , or radiographic evidence of loosening of the components . Life-table analysis reveals a 95.6 % clinical survival rate at 14 years , with no radiographically loose components . Confidence interval is + /- 4.2 % . There were 4 revisions , but none for aseptic loosening , and there are no impending revisions . Thirty-seven patients ( 49 knees ) were known to be deceased as of April 1993 , and 8 other patients are lost to followup . Clinical results for patients with pre- and postoperative Hospital For Special Surgery knee scores show 72 knees rated excellent and 11 good ( mean score , 90 points ) . The 4 failures were rated poor . Mean flexion was 100 degrees . Radiographs of 93 knees were evaluated using the criteria of the Knee Society . Average overall alignment was 5 degrees valgus . Radiolucencies were present in 29 of 78 femoral components with adequate radiographs , and averaged 1 mm in 1 zone . Tibial radiolucency was present in 42 of 93 tibiae , again averaging 1 mm in 1 zone , with no loose pegs . In comparison with the first series of total condylar prostheses , this series showed comparable clinical results , with improved radiographic results , and no radiographic failures Our study examines the clinical , radiographic , and patient satisfaction outcome of the cemented Modular Porous-Coated Anatomic ( PCA ) total knee arthroplasty with a minimum 5-year follow up . All data were gathered prospect ively and consecutively . Patient satisfaction was assessed with a self-administered survey . Statistical analysis examined the effect of 17 patient factors , 19 surgical factors , and postoperative continuous passive motion use on range of motion ( ROM ) and HSS scores at 2 years . Seventy-eight Modular PCA arthroplasties performed by 9 orthopedic surgeons on 71 patients between January 1988 and November 1989 are reported in this study .  Preoperative HSS scores averaged 51.2 and improved to an average of 89 at 1 and 2 years , and 86 at 5 years after surgery ( 90 % good or excellent ) . ROM changed after surgery through improvement in preoperative knee flexion contracture , but not in increased knee flexion . One patient underwent reoperation for patellar instability , and one patient 's arthroplasty was revised at 53 months for late instability . The total reoperation rate for any reason was 7.7 % . Zonal analysis for progressive radiolucency at the bone-cement interface showed increasing frequency of narrow ( < 1 mm ) radiolucencies concentrated on the anterior and medial aspect of the tibial tray . Ninety-eight percent of patients responded to an outcome question naire , and 96 % rated themselves improved . The Kaplan-Meier probability of an implant surviving without loosening at 5 years was 100 % . The Modular PCA TKA has a low incidence of patellofemoral problems , is clinical ly successful , and results are stable at a minimum 5-year follow-up examination We studied CMW-1 bone cement with gentamicin in the laboratory and in a r and omized clinical study . Palacos bone cement containing gentamicin was used as the control . In the pre clinical evaluation , the CMW cement had slightly less mechanical strength . In the clinical study , 51 patients ( 51 knees ) operated on with total knee arthroplasty were studied for 2 years . We used radiostereometric analysis to measure migration of the tibial components , r and omized to fixation with either of the two types of cement . The extent and pattern of migration were similar in both groups , and we found no differences in the number , size and extent of radiolucent lines or clinical outcome . No complications occurred . Our findings suggest a need for more studies of CMW-1 bone cement containing gentamicin in a larger cohort of patients Mobile bearings were introduced to improve wear and knee kinematics . By uncoupling the forces generated at the articulation from the implant-bone interface this would , theoretically , also improve the fixation of the implant to bone . We did this study to evaluate whether mobile bearings  improve the fixation of the tibial component to bone .  Fifty-two consecutive knees in 47 patients ( average age , 72 years ; range , 62 - 84 years ) with primary osteoarthrosis were r and omized into two groups to receive a cemented total knee arthroplasty with either a fixed-bearing or mobile-bearing tibial component . The quality of fixation was analyzed with radiostereometric analysis for up to 2 years . Mobile bearings did not improve fixation . Both magnitudes and directions of component rotations were similar , and the number of implants with continuous migration was almost identical . Both implant types had a combination of subsidence and lift-off , but where the mobile bearing implants displayed more of subsidence , the fixed bearing knees showed more lift-off . It might be that the somewhat stiffer cobalt-chromium baseplate or the different joint conformity used in the mobile-bearing knees counteracts any potential effects of the mobile bearing . Level of Evidence : Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence Twenty-six women and three men ( 34 knees ) with osteoarthrosis were operated with the Miller-Galante I ( Zimmer , Warsaw , IN ) knee prosthesis . The patients were r and omized to either cemented or uncemented fixation of the tibial component . All patients received a TiVaAl alloy tibial plate with four pegs and titanium fiber-mesh undersurface . In the uncemented knees four screws were added . The fixation of the tibial component was determined by roentgen stereophotogrammetric analysis during the first 2 postoperative years . Rotations of the entire tibial component were recorded , as well as proximal or distal translation of various parts of the prosthetic edge corresponding to subsidence and lift-off . The uncemented components displayed almost all rotation and translation during the first 6 weeks , whereas the cemented ones displayed a more gradually increasing migration during the 2 years . Tibial component rotation about the sagittal axis was significantly increased in the uncemented knees throughout the investigation period . This corresponded to increased subsidence medially or laterally in the uncemented knees , whereas lift-off was equal in the two groups . Thin ( 8.5 mm ) uncemented tibial components displayed more subsidence than the thicker ones at the medial or lateral edge 3 months after surgery 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 We performed a survival analysis on 354 cemented primary Press-Fit Condylar ( PFC ) total knee arthroplasties ( TKA ) in 277 patients with prospect i ve follow-up ( mean , 6 years ; range , 2 - 11.7 years ) . No patient was lost to follow-up . Using revision for all causes as the endpoint , the cumulative survival rate at 10 years was 95.5 % ( 95 % confidence interval , 90.1%-98.1 % ) . The 10-year clinical outcome available on 41 patients was good , with significant improvement in pain and mobility assessment s using the Nottingham data collection system . Our results indicate that the cemented PFC TKA has good long-term survival based on revision as the endpoint . Revision for implant failure is rare and brings to question modifications to this prosthesis 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 We conducted a prospect i ve , r and omized study of 45 patients to evaluate 3 different uncemented tibial component design s in total knee arthroplasty . The stability of the components was assessed by  radiostereometry ( RSA ) , both as migration during 2 years and as inducible displacement at 2 years . The PCA resurfacing , the Tricon stem and the Tricon-M prosthesis groups showed a similar level of migration at 2 years , about 1.4 mm . In response to externally applied rotatory forces , the Tricon groups rotated more than the PCA group , interpreted as a consequence of the more conforming articular surface in the Tricon design . The series was divided into one group of continuously migrating prostheses with a poor prognosis ( unstable , one third ) and another group of prostheses in which migration stopped after 1 year ( stable , two thirds ) . With this classification , no differences between the prostheses design groups were revealed . However , the unstable group showed a larger inducible displacement by provocation , an association hitherto not established 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 VersaBond is a newly developed bone cement . To investigate its clinical performance , VersaBond was compared to Palacos R in a prospect i ve r and omized study in total knee replacement . Fifty-nine patients ( 61 knees ) undergoing total knee replacement were r and omized to either VersaBond or Palacos R bone cement and followed for 24 months using radiostereometric analysis ( RSA ) . Up to 2 years there were no significant differences in clinical performance between the two cements . The mean/median values for implant migration were very similar for the two bone cements , as were the dispersion , and distribution of outliers . Also the proportion " stable " and " continuously migrating " implants was similar between the two cements . The result of this study indicates that VersaBond bone cement will perform at least equally as well as Palacos R in total knee replacement as regards as aseptic loosening We present the long-term results of the  Kinematic Condylar Knee Arthroplasty  followed in a prospect i ve fashion . Between October 1982 and March 1988 , 404 consecutive replacement arthroplasties were carried out on 335 patients . Of these , 354 knees had osteoarthritis , 45 rheumatoid arthritis and five other diagnoses . At the time of final follow-up 158 patients ( 188 knees ) had died . No patient was lost to follow-up . The minimum follow-up for all living patients was ten years ( 10 to 17 ) . The mean age at surgery was 68 years ( 30 to 92 ) . There were seven complications ( 1.7 % ) . Sixteen knees ( 3.9 % ) were revised , four because of infection . Survivorship was 99.4 % ( CI 97.9 to 99.8 ) at five years , 98.2 % ( CI 96.1 to 99.2 ) at ten years and 92.6 % ( CI 87.6 to 95.6 ) at 17 years
target: INTERPRETATION There was a clinical ly relevant association between early migration of TKPs and late revision for loosening .
background: 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 .