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 Knee joint loading and tibial component loosening. RSA and gait analysis in 45 osteoarthritic patients before and after TKA. The beneficial effect of hydroxyapatite lasts Migration of a cemented fixed-bearing, polished titanium tibial baseplate (Genesis II) at ten years : a radiostereometric analysis. Similar early migration when comparing CR and PS in Triathlon™ TKA: A prospective randomised RSA trial. The stability of three different cementless tibial components. A randomized radiostereometric study in 45 knee arthroplasty patients. Denosumab reduces early migration in total knee replacement Absence of a Tourniquet Does Not Affect Fixation of Cemented TKA: A Randomized RSA Study of 70 Patients. Preoperative gait patterns and BMI are associated with tibial component migration Kinematics and early migration in single-radius mobile- and fixed-bearing total knee prostheses. Early Migration of the Tibial Component of the Buechel-Pappas Total Ankle Prosthesis Mobile vs. fixed meniscal bearing in total knee replacement: a randomised radiostereometric study. Bone morphology in relation to the migration of porous-coated anatomic knee arthroplasties : a roentgen stereophotogrammetric and histomorphometric study in 23 knees. The effect of Palamed® G bone cement on early migration of tibial components in total knee arthroplasty Cemented tibial component fixation performs better than cementless fixation Comparison of the tibiofemoral rotational alignment after mobile and fixed bearing total knee arthroplasty Lateral subvastus approach with osteotomy of the tibial tubercle for total knee replacement: a two-year prospective, randomised, blinded controlled trial.
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 a prospect i ve study of gait and tibial component migration  in 45 patients with osteoarthritis treated by total knee arthroplasty ( TKA ) .  Migration  was measured over two years using roentgen stereophotogrammetry . We used the previously established threshold of 200 microm migration in the second postoperative year to distinguish two groups : a risk group of 15 patients and a stable group of 28 patients . We performed  gait analysis before operation and at six months and at two years after TKA . On all three occasions we found significant differences between the two groups in the mean sagittal plane moments of the knee joint . The risk group walked with higher peak flexion moments than the stable group . The two groups were not discriminated by any clinical or radiological criteria or other gait characteristics . The relationship which we have found between gait with increased flexion moments and risk of tibial component loosening warrants further study as regards the aetiology of prosthetic loosening and possible methods of influencing its incidence 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 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 OBJECTIVES The objective of this study was to compare the early migration of the cruciate retaining and posterior stabilising versions of the recently introduced Triathlon ™ total knee system , with a view to predicting long term fixation performance . METHODS Sixty patients were prospect ively r and omised to receive either Triathlon ™ posterior stabilised cemented knee prosthesis or Triathlon ™ cruciate retaining cemented knee prosthesis . Tibial component migration was measured by radiostereometric analysis postoperatively and at three months , one year and two years . Clinical outcome was measured by the American Knee Society Score and Knee Osteoarthritis and Injury Outcome Score . RESULTS There were no differences in rotation around the three coordinal axes or in the maximum total point motion ( MTPM ) during the two year follow-up . The posterior stabilised prosthesis had more posterior-anterior translation at three months and one year and more caudal-cranial translation at one year and two years . There were no differences in functional outcome between the groups . CONCLUSION The tibial tray of the Triathlon ™ cemented knee prosthesis showed similar early stability . LEVEL OF EVIDENCE Level I. ARTICLE SUMMARY Article focus : This was a prospect i ve r and omised trial aim ing to compare the single radius posterior stabilised ( PS ) Triathlon ™ total knee arthroplasty ( TKA ) to the cruciate retaining Triathlon ™ TKA system with regard to fixation . Strengths and limitations of this study : Strength of this study was that it is a r and omised prospect i ve trial using an objective measuring tool . The sample size of 25 - 30 patients was reportedly sufficient for the screening of implants using RSA [ 1 ] . TRIAL REGISTRATION Clinical Trials.gov Identifier : NCT00436982 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 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 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 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 mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component . This would reduce the contact stresses and wear which in turn may have a positive effect on the fixation of the prosthesis to the bone and thereby decreases the risk for loosening . The aim of this study was to evaluate early migration of the tibial component and kinematics of a mobile-bearing and fixed-bearing total knee prosthesis of the same single-radius design . METHODS Twenty Triathlon single-radius posterior-stabilized knee prostheses were implanted ( 9 mobile-bearing and 11 fixed-bearing ) .  Fluoroscopy and roentgen stereophotogrammetric analysis ( RSA ) were performed 6 and 12 months post-operatively . FINDINGS The 1 year post-operative RSA results showed considerable early migrations in 3 out of 9 mobile-bearing patients and 1 out of 11 fixed-bearing patients . The range of knee flexion was the same for the mobile-bearing and fixed-bearing group . The mobile insert was following the femoral component during motion . INTERPRETATION Despite the mobile insert following the femoral component during motion , and therefore performing as intended , no kinematic advantages of the mobile-bearing total knee prosthesis were seen . The fixed-bearing knee performed as good as the mobile-bearing knee and maybe even slightly better based on less irregular kinematics and less early migrations 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 52 knees scheduled for a total knee arthroplasty were r and omised to either a fixed or a mobile polyethylene bearing . The design was identical in all parts . The knee systems used were the Rotaglide Total Knee System ( RTK ) and the Nuffield Total Knee System ( NTK ) , both from the same manufacturer ( Corin Medical Ltd. , UK ) . All knees implanted were uncemented . The patients were followed for 2 years clinical ly and with radiostereometric analyses to assess migration over time and inducible displacement of the tibial component . Separate analysis of the mobility of the tibial insert in the knees with a mobile bearing was also made . The migration measured with RSA between the 1st and 2nd year expressed as maximum total point motion ( MTPM ) might predict the risk of loosening of the implant . There were no differences between the groups regarding clinical outcome ( HSS Knee score ) , migration or inducible displacement during the 2 years follow-up . The movement between the tibial tray and the mobile meniscal insert expressed as maximum total point motion ( MTPM ) was 6.8+/-3.3 mm at the 1st year follow-up The quality of the subchondral bone in total knee arthroplasty ( TKA ) may be important for the outcome . We correlated a histomorphologic analysis of the prosthetic bone bed to micromotion as analyzed by  roentgen stereophotogrammetric analysis ( RSA ) .  Twenty-three knees , both osteo- and rheumatoid arthritic were studied . The mean migration after 1 year was 1 mm ( 0.21 - 2.68 ) , with no correlation to the bone variables or diagnosis . One patient underwent revision after 3 years because of pain . One patient underwent revision after 15 years because of aseptic loosening . This patient appeared stable according to changes in maximum total point motion ( MTPM ) , but the prosthesis migrated continuously according to segment motion . Prosthetic migration increased after 10 years , zones started to evolve , and the patient became symptomatic after 13 years . A biopsy of the bone bed was taken in all patients . A larger percentage of trabecular bone and a larger relative area of unmineralized osteoid surface were found in patients with rheumatoid arthritis compared with those with osteoarthritis . The latter finding is probably a result of increased bone turnover . In conclusion , no support currently exists for the idea that preoperative bone quality , evaluated as bone histomorphometry , has any impact on prosthetic micromotion in knee prostheses 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 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 Purpose The anatomical l and mark for the anteroposterior ( AP ) axis of the proximal tibia and its variability was investigated in order to determine whether a certain l and mark could be employed as a reference axis for the proximal tibia after the rotating platform mobile bearing and fixed bearing total knee arthroplasties ( TKAs ) . Methods Eighty primary osteoarthritic knees were r and omized to undergo either rotating platform mobile bearing ( Group A , n = 40 ) or fixed bearing ( Group B , n = 40 ) TKAs , and were followed up for 31 and 30 months , respectively . The AP axes were defined for the distal femur , proximal tibia , ankle , and each TKA component on the reconstructed CT scan and the angles between the distal femoral AP axis and those of each bone or component were estimated . Clinical and radiographic outcomes were evaluated during the follow up . Results A significant difference was seen between the preoperative and postoperative rotational position of the proximal tibia relative to the distal femur following rotating platform mobile bearing TKA ( P = 0.014 ) whereas no such difference was seen after fixed bearing TKA .  The mean postoperative alignment of the tibia differed between the two groups ( Group A : Group B = −2.9:0.2 , P = 0.010 ) and its variability was significantly greater in group A ( P < 0.001 ) . There were no differences in the clinical outcomes including range of motion , knee society score , function score , HSS , and WOMAC score as well as the mean postoperative coronal tibiofemoral alignment between the two groups . Conclusion The unpredictable change in the rotational axis of the tibia and its broad variability after rotating platform mobile bearing TKA may provide a warning against the use of a fixed l and mark for establishing tibial rotational alignment . Level of evidence Prospect i ve comparative study , Level II The lateral subvastus approach combined with an osteotomy of the tibial tubercle is a recognised , but rarely used approach for total knee replacement ( TKR ) . A total of 32 patients undergoing primary TKR was r and omised into two groups , in one of which the lateral subvastus approach combined with a tibial tubercle osteotomy and in the other the medial parapatellar approach were used . The patients were assessed radiologically and clinical ly using measurement of the range of movement , a visual analogue patient satisfaction score , the Western Ontario McMasters University Osteoarthritis Index and the American Knee Society score . Four patients were lost to the complete follow-up at two years . At two years there were no significant differences between the groups in any of the parameters for clinical outcome . In the lateral approach group there was one complication due to displacement of the tibial tubercle osteotomy and two osteotomies took more than six months to unite . In the medial approach group , one patient had a partial tear of the quadriceps . There was a significantly greater incidence of lateral patellar subluxation in the medial approach group ( 3 of 12 ) compared with the lateral approach group ( 0 of 16 ) ( p = 0.034 ) , but without any apparent clinical detriment . We conclude that the lateral approach with tibial tubercle osteotomy is a safe technique with an outcome comparable with that of the medial parapatellar approach for TKR , but the increased surgical time and its specific complications do not support its routine use . It would seem to be more appropriate to reserve this technique for patients in whom problems with patellar tracking are anticipated
Cemented and uncemented tibial components had different migration patterns .
For cemented tibial components there was no difference in migration between all-poly and metal-backed components , between mobile bearing and fixed bearing , between cruciate retaining and posterior stabilized .
Furthermore , no difference existed between TKR measured with model-based RSA or marker-based RSA methods .
For uncemented TKR there was some variation in migration with the highest migration for uncoated TKR .
Interpretation - The results from this meta- analysis on  RSA migration of TKR  are in line with both the survival analyses results from joint registries of these TKRs as well as revision rates results from meta-analyses , thus providing further proof for the association between early migration and late revision for loosening .
Purpose - We performed a systematic review and meta-analyses to evaluate the early and long-term migration patterns of  tibial components of TKR of all known RSA studies .