A Systematic Review on Performance of the Vanguard Complete Knee System Author: Jing Xie, Ph.D. June 30, 2011 Abstract A systematic review was conducted to evaluate the clinical performance of the Vanguard Complete Knee System (Biomet, Warsaw, IN). A total of 15 data sources were identified, which included published and unpublished clinical studies and National Joint Registry (NJR) annual reports. The performance parameters of interest were implant survivorship and clinical patient outcomes. A comparison of implant survivorship between the Vanguard Knee and various baselines of total knee arthroplasty (TKA) shows that the performance of the Vanguard Knee, with various fixation options, is comparable to that of overall TKA and competitive TKA products. 1 15 The analysis of patient clinical outcomes, American Knee Society Score (AKSS), shows that the majority of patients who received the Vanguard Knee achieved good to excellent function with demonstrated survivorship of 97.7% at 5 years in over 16,000 knees. 1 15 Introduction The proven clinical heritage of the AGC, Maxim, and Ascent Total Knee Systems 16 18 and the combined state-of-the-art design features have allowed Biomet to produce the most comprehensive total knee replacement system on the market. Introduced in 2003, the Vanguard Complete Knee System offers the flexibility to change from a cruciate retaining (CR) to a posterior stabilized (PS) within a single system, while also featuring optimal congruency in the coronal plane resulting in 1:1 conformity and allowing complete interchangeability between femoral and tibial components. Device Description The Vanguard Complete Knee System consists of four main components: femoral component, tibial tray, tibial bearing and patellar component. For the purpose of this systematic review, both fixed and mobile bearing Vanguard Knee designs are included. Fig. 1 Vanguard PS Fixed Bearing Construct Vanguard Knee Fixed Bearing Construct Design (Figure 1): 1. Anatomically specific, cobalt chrome femoral component Available in 10 sizes from 55 to 80 mm, in average 2.4 mm increments M/L and average 2.3 mm increments A/P, with both CR and PS options, available for either cemented or cementless fixation. 2. Tibial tray Available as either a titanium alloy baseplate (with modular stems for cemented or cementless fixation) or cobalt chrome alloy baseplate (with fixed I-beam or cruciate fin for cemented fixation). Available in 9 sizes with consistent 4 mm M/L increments from 59 to 91 mm. 3. ArCom Direct Compression Molded (DCM) Ultra High Molecular Weight Polyethylene (UHMWPE) tibial bearing Available in three CR options: CR, CR Lipped and Anterior Stabilized (AS); and two PS options: PS and PS+, with up to 6 sizes per type and up to 8 thicknesses per size. The CR and PS femoral components feature complete size interchangeability with their respective primary bearings, with the exception of the AS bearing.
4. Dome-shaped ArCom UHMWPE patellar component Available in multiple diameters, thicknesses and peg configurations. Table 1. Fixed and Mobile Bearing Vanguard Knees Included in the Vanguard Knees 1 15 Number of Cases Analyzed Percentage Fixed Bearing 13848 84% Fixed Bearing Monobloc* Mobile Bearing* (Deep Dish, Vanguard ROCC and Vanguard Highflex RP) 1848 11% 862 5% TOTAL 16558 100% *have NOT been cleared or approved in the US by the FDA Materials and Methods Fig. 2 Vanguard CR Rotating Platform Construct Vanguard Knee Rotating Platform Construct Design (Figure 2): 1. Anatomically specific, cobalt chrome femoral component Available in 10 sizes from 55 to 80 mm, in average 2.4 mm increments M/L and average 2.3 mm increments A/P, available for cemented fixation only. 2. Central cone tibial tray Central tibial tray design offered in cobalt chrome alloy with three surface finishes: Interlok finish on the fixation surface, polished planar articulating surface and the bore has a satin finish. Available in 9 different sizes with consistent 4 mm M/L increments from 59 to 91 mm. The 59, 63 and 67 mm trays feature a 35 mm long tapered stem with 4 ribs, while the remaining sizes feature 40 mm long tapered stem with 4 ribs. 3. ArCom Direct Compression Molded (DCM) Ultra High Molecular Weight Polyethylene (UHMWPE) tibial bearing Vanguard Rotating Platform deep-dish bearings are offered in nine symmetrical sizes that correspond to femoral component sizes. Bearings articulate with any size tibial tray; however, bearing overhang will occur with significant bearing/tray mismatch. 4. Dome-shaped ArCom UHMWPE patellar component Available in multiple diameters, thicknesses and peg configurations. Dataset Identification and Appraisal Datasets relevant to the Vanguard System were searched from three sources: published literature, clinical experience and clinical investigation. Clinical experience includes data from post-market clinical studies and NJR data and annual reports. Any clinical investigations such as regulated pre-market clinical studies were also searched. Only datasets available in English were included. A set of potential datasets were identified which contained data on the Vanguard Knee. Each dataset was appraised based on suitability for contribution to the assessment of performance of the Vanguard Knee. Specifically, data suitability was examined based on: 1. Whether the dataset was generated from a patient population where the Vanguard Knee was the treatment intention AND 2. Whether the dataset contained information on implant survivorship and AKSS which could be used to assess the performance of the Vanguard Knee Additionally, contribution assessment included an evaluation of the study design in the data collection (e.g. randomized controlled, consecutive case series, etc.), specific measures collected (e.g. revision, AKSS, length of follow-up and poolability). This assessment helps determine how each dataset was utilized in assessing safety and performance of the Vanguard Complete Knee System. Appendix 1 summarizes the datasets chosen to be included in this review and the corresponding suitability and contribution assessment. 2 A Systematic Review on Performance of the Vanguard Complete Knee System
Data Analysis I. Demographics Overall gender was collected in all subsets and summarized in Table 2. The gender distribution is similar to that reported in various NJRs. Table 2. Gender Distribution 1 15 Male Female All Vanguard Knees 42% (5535/13140)* 58% (7605/13140)* 43% 57% SKAR** 42% 58% UKNJR 43% 57% NZNJR 48% 52% *based on datasets reporting gender **based on graphic information reported 2009 II. Implant Survivorship Implant survivorship was analyzed using three methods: 1. Raw Revision Rate Raw Revision Rate was used to calculate the unadjusted percentage of implants known to have failed. This rate does not take into consideration implant survival time for all cases, including those that did not fail. This factor is critical for accurate device performance evaluation. 2. Cumulative Survival Rate Kaplan-Meier Curve Cumulative Survival Rate uses implant survival time to calculate an estimate on the fraction of implants survived over a certain period of time. However, this calculation, when derived from several datasets cannot be standardized due to variation in the length of follow-up. 3. Revision per 100 Observed Component Year (OCY) The formula for this calculation is: Number of Revisions for any reason X 100 Total Number of Observed Component Year For implant survivorship analysis, revisions for any reasons will be included. When data is available at the case level, it will be used for overall data pooling. If the data was available in summary form only, data pooling was performed whenever possible employing statistical method by Sutton et al 19 ; otherwise it will be reported as is. III. Patient Clinical Outcomes - AKSS The AKSS, developed by The Hospital for Special Surgery, consists of a functional measurement and a composite measure of knee pain, stability and range of motion. The maximum function score is 100 which can be obtained by a patient who can walk an unlimited distance and can go up and down stairs normally. The maximum composite is also 100 which can be obtained from a knee that is well aligned with no pain, can achieve 125 of motion and negligible anteroposterior and mediolateral instability. This tool is used to evaluate patient satisfaction post TKA. The endpoint considered for this analysis was the sum of the function and composite measures, thus a maximum of 200 points would be allowed at any one assessment. Baselines To establish the comparative performance of the Vanguard Knee, implant survivorship will be further compared to that of baseline as reported in NJR annual reports and included the following variants within TKA: 1. TKA product family per NJRs 2. Pooled competitive TKA products Where Total Number of Observed Component Year = n i =1 individual years from implantation This method allows for comparison among datasets where the calculation has been adjusted for the two main factors influencing the value of individual cohorts: number of cases and number of days in the follow-up period. Revision per 100 OCY was introduced to orthopedic research in Australian National Joint Registry and has been adopted by the New Zealand National Joint Registry and the European Arthroplasty Register as a standard method of reporting revision rates. 3 A Systematic Review on Performance of the Vanguard Complete Knee System
Results Implant Survivorship Implant survivorship analysis was performed using a total of 13 datasets. The results on Raw Revision Rate and Revision per 100 Observed Component Years are presented in Table 3. Sensitivity analysis was conducted to assess how each dataset s contribution impacts the results from data pooling as shown in Table 4. Table 3. Raw Revision Rate and Revision per 100 OCY Vanguard Knee 1 10,12,14 15 Total No. of Cases Analyzed Total No. of Revisions 13877 132 Raw Revision Rate 0.95 (0.79, 1.11) Total No. of Cases Reported Survival Time Total No. of Revisions Reported Survival Time Total No. of Component Year 13757 130 24193 Revision per 100 OCY (95% CI) 0.54 (0.45, 0.64) Table 4. Sensitivity Analysis of Each Contributing Dataset 1 10,12,14 15 Dataset Excluded Number of Cases Excluded Revision Excluded OCY Excluded Raw Revision Rate Percent Revision per 100 OCY 1 70 0 150.8138 0.96 (0.79, 1.12) 0.55 (0.46, 0.65) 4 43 0 31.46663 0.95 (0.79, 1.12) 0.55 (0.46, 0.65) 6 600 10 2131.85 0.92 (0.75, 1.09) 0.55 (0.46, 0.66) 7 265 0 248.32 0.97 (0.80, 1.14) 0.55 (0.46, 0.65) 9 294 0 348.2 0.97 (0.80, 1.14) 0.55 (0.46, 0.66) 10 81 1 82.28057 0.95 (0.78, 1.12) 0.54 (0.45, 0.64) 11 357 6 1768.022 0.93 (0.77, 1.10) 0.56 (0.47, 070) 12 1101 8 2769.767 0.97 (0.80, 1.15) 0.58 (0.48, 0.69) 14 6659 40 10417.29 1.27 (1.01, 1.54) 0.67 (0.54, 0.82) 15 4009 58 5786 0.75 (0.57, 0.93) 0.40 (0.32, 0.50) 17 120 2 NA 0.94 (0.78, 1.10) NA 20 237 4 312 0.94 (0.77, 1.10) 0.54 (0.45, 0.64) 21 41 3 147.3305 0.93 (0.77, 1.10) 0.54 (0.45, 0.64) 4 A Systematic Review on Performance of the Vanguard Complete Knee System
Kaplan-Meier survival analyses were conducted for each of the 10 datasets which had: 1) Case level data or poolable summarized and 2) A minimum of 1 year survival data. The Vanguard Knee demonstrated excellent survival with this data, demonstrating an overall survivorship of 97.7% at 5 years (Table 5). 1,3 5,7 10,13,15 Kaplan-Meier survival analysis for each dataset performed equally well as shown in Table 6. 1,3 5,7 10,13,15 Figure 3 illustrates the distribution of the cumulative survival rates based on datasets with case-level details, a total of 9511 cases. This survival curve further confirms the excellent survival for the Vanguard Knee. 1,3 5,7 9,13 15 1.0 Table 5. Kaplan-Meier Survival Analysis Pooled Survivorship (95% CI) 1,3 5,7 10,13,15 No. of Cases Year 1 Year 3 Year 5 16201 99.5 (99, 100) 98.7 (97.9, 99.5) 97.7 (95.8, 99.7) Table 6. Kaplan-Meier Survival Analysis Individual Datasets Survivorship (95% CI) 1,3 5,7 10,13,15 Dataset Year 1 Year 3 Year 5 VGDS6 99.7 (98.7, 99.9) 98.8 (97.6, 99.4) 97.2 (94.3, 98.6) VGDS11 99.2 (97.4, 99.7) 98.5 (96.5, 99.4) 98.2 (96.0, 99.2) VGDS12 99.5 (98.9, 99.8) 99.1 (98.1, 99.6) VGDS14 99.7 (99.5, 99.8) 98.6 (98.0, 99.0) VGDS21 97.6 (83.9, 99.7) 94.7 (80.3, 98.7) VGDS1 100 VGDS9 100 VGDS7 100 98.8 (98.2, 99.3) 97.2 (95.5, 98.2) 99.4 (97.6, 99.8) 97.8 (95.2, 99.0) 98.8 (97.9, 99.4) 97.2 (95.6, 98.2) 99.7 (98.1, 100) Danish NJR 95.6 (94.4, 96.8) Survival Probability 0.8 0.6 0.4 0.2 0.0 0 1 2 3 4 5 Follow up Time Censored 95% Confidence Limits Fig. 3 Vanguard Knee Cumulative Survival Rate Distribution 5 A Systematic Review on Performance of the Vanguard Complete Knee System
The Swedish and Danish Registries have also reported Vanguard Knee performance in comparison to the AGC Knee. Since the parameters used for performance reporting in these registries are different and cannot be pooled with other Vanguard Knee datasets, they are reported as is in Table 7. Table 7. Risk of Revision 11,13 NJR Condition Reference Vanguard Knees Risk of Revision 95% CI Swedish OA/TKA AGC 924 1.63 0.98, 2.71 Swedish RA/TKA AGC 49 2.58 0.56, 11.84 Danish ALL AGC V2 2071 1.10 0.82, 1.48 Comparison to Baselines A comparison between implant survivorship of the Vanguard Knee and baselines was also conducted. Baseline is defined as results from the meta analysis, overall Vanguard Knee raw revision rate and revision per 100 OCY, and Kaplan-Meir survivorship, with pooled survivorship and 95% CI. Raw revision rate, revision per 100 OCY and Kaplan-Meier survival were first compared to the TKA product family reported in various NJRs. All three implant survivorship parameters of the Vanguard Knee were comparable to the baselines of TKA product families 1 15 as illustrated in Tables 8 and 9. Implant survivorship of the Vanguard Knee was then compared to that of various competitive TKA products reported in NJRs. 1 15 This comparison is detailed in Tables 10 and 11. Table 8. Comparison to NJR Data TKA Product Family 1 15 Revision per 100 OCY (95% CI) Raw Revision Rate in % (95% CI) All Vanguard Knees 0.54 (0.45, 0.64) NZNJR (11 yrs) ALL TKA 0.53 (0.50, 0.56) ALL TKA 0.75 (0.75, 0.79) Cemented TKA 0.75 (0.73, 0.78) Hybrid TKA 0.73 (0.70, 0.77) Cementless TKA 0.86 (0.82, 0.90) N = 13757 N = 45969 N = 231409 N = 118484 N = 57614 N= 55311 All Vanguard Knees 0.95 (0.79, 1.11) NZNJR (11 yrs) ALL TKA 2.23 (2.1, 2.37) ALL TKA 2.86 (2.79, 2.93) Cemented TKA 2.7 (2.6, 2.8) Hybrid TKA 3.0 (2.85, 3.14) Cementless TKA 3.16 (3.01, 3.31) N = 13877 N = 45969 N = 231409 N = 118484 N = 57614 N= 55311 6 A Systematic Review on Performance of the Vanguard Complete Knee System
Table 9. Revision Rate Comparison to NJR Data TKA Product Family 1 15 CPR Cumulative Percent Revision Rate (1-Survivorship) (95% CI) N Total CPR at 1 yr in Percent CPR at 3 yrs in Percent CPR at 5 yrs in Percent All Vanguard Knees 16201 0.5 (0.00, 1) 1.3 (0.4, 2.1) 2.3 (0.3, 4.2) TKA 231409 0.8 (0.2, 1.4) 2.2 (0.74, 3.61) 2.9 (0.94, 4.81) UKNJR TKA 39970 2.0 (2.0, 2.1) 2.8 (2.7, 3.0) SKAR TKA* Unknown 0.6 2.4 2.6 Danish NJR TKA Cementless* 2.5 5.0 7.0 Danish NJR TKA Cemented* 49169 1.5 3.5 4.5 Danish NJR TKA Hybrid* 1.0 3.0 4.0 *based on graphic information Table 10. Comparison to NJR Data Competitors Products* 1 15 Revision per 100 OCY (95%CI) All Vanguard Knees 0.54 (0.45, 0.64) NexGen Knees 0.53 (0.5, 0.56) Genesis II Knees 0.79 (0.74, 0.84) P.F.C. Sigma Knees 0.66 (0.61, 0.71) Triathlon Knees 0.61 (0.52, 0.72) N 13757 53448 36070 31728 16434 Raw Revision Rate (95% CI) 0.95 (0.79, 1.11) 1.96 (1.85, 2.08) 2.72 (2.55, 2.89) 2.26 (2.09, 2.42) 0.95 (0.8, 1.1) N 13877 53448 36070 31728 16434 *based on Australian and New Zealand NJR latest reports Table 11. Revision Rate Comparison to NJR Data Competitors Products* 1 15 CPR Cumulative Percent Revision (1-Survivorship) N Total CPR at 1 yr in Percent (95% CI) CPR at 3 yrs in Percent (95% CI) CPR at 5 yrs in Percent (95% CI) All Vanguard Knees 16201 0.5 (0.00, 0.01) 1.3 (0.5, 2.1) 2.3 (0.3, 4.2) Genesis II Knees 36070 1.14 (0.84, 1.44) 2.83 (1.75, 3.92) 3.44 (1.95, 4.92) NexGen Knees 53448 0.65 (0.24, 1.06) 1.8 (0.93, 2.68) 2.39 (1.06, 3.72) P.F.C. Sigma Knees 31728 0.9 (0.22, 1.58) 1.89 (1.17, 2.6) 2.56 (1.55, 3.56) Triathlon Knees 16434 0.8 (0.67, 0.92) 1.53 (0.73, 2.34) Insufficient follow-up *based on Australian and UK NJR latest reports 7 A Systematic Review on Performance of the Vanguard Complete Knee System
Patient Outcomes The AKSS, including both objective and function scores were collected in 6 of the datasets used in analysis. Statistically significant improvement in AKSS was found preoperatively to 1-year follow-up. 2 7 Summarized AKSS statistics from pooled datasets can be found in Figures 4 and 5. 100 80 AKS - Objective Score AKS - Function Score Discussion The performance of the Vanguard Knee was evaluated based on implant survivorship and AKSS. Clinical data was gathered from a variety of clinical datasets, including both clinical studies and national joint registries. This approach ensures a comprehensive review of the Vanguard Complete Knee System. The analysis shows that the survivorship of the Vanguard Knee, based on all three parameters, is well within that of overall results of TKA with various bearing configurations and fixations (baselines). 1 15 Patients who have received the Vanguard Knee demonstrated improved clinical outcomes from preoperative to 1-year follow-up based on the AKSS. 2 7 60 40 20 0 Preop 6 m 1 y 2 y 3 y 5 y Fig. 4 Fixed Bearing - Mean AKS Scores 2 7 Conclusion This review demonstrates that the Vanguard Complete Knee System demonstrated consistent and excellent clinical performance based on worldwide clinical data, with the majority of patients achieving good to excellent function with demonstrated survivorship of 97.7% at 5 years. 1 15 100 AKS - Objective Score AKS - Function Score 80 60 40 20 0 Preop 6 m 1 y 2 y 3 y Fig. 5 Mobile Bearing - Mean AKS Scores 2 7 8 A Systematic Review on Performance of the Vanguard Complete Knee System
Appendix 1 Data Suitability Criteria Criteria Description Suitability Grading Appropriate Device Was the data generated from the device in question? D1 Actual device D2 Comparable device D3 Other device Appropriate Indications Appropriate Patient Group Was the device used for the same intended use (e.g., methods of deployment, application, etc.)? Was the data generated from a patient group that is representative of the intended treatment population (e.g., age, sex, etc.) and clinical condition (i.e., disease, including state and severity)? A1 Same use A2 Minor deviation A3 Major deviation P1 Applicable P2 Limited P3 Different population Type of Data Will the data address safety or performance of the device in question? T1 Safety T2 Performance T3 Both T4 Neither Criteria of Data Contribution Criteria Description Contribution Grading Data source type Type of studies from which the data is collected. T1 RCT T2 Cohort T3 Case-control T4 Case series Outcome measures Does the dataset include implant survivorship and/or AKS? O1 Survivorship O2 AKS O3 Both Follow-up Is the duration of follow-up long enough to assess the treatment effects and identify complications? F1 Yes F2 No Poolability Can the data be pooled with other datasets? P1 Yes P2 No 9 A Systematic Review on Performance of the Vanguard Complete Knee System
Data Sources Available as of June 2011 Data Source (Internal ID) 1 4 6 7 9 10 11 12 14 15 16 17 Data Source Description (Location) Prospective Comparison of MIS/Usual Technique for Vanguard (Japan) Regenerex Tibial Tray Multi-Center data Collection (US) Prospective on Vanguard MIS Approach (US) Prospective Comparative on Vanguard (Korea) Prospective Controlled on Vanguard Deep Dish Rotating Platform IDE (US, Germany, Austria and Finland) Prospective Randomized Controlled on Vanguard Deep Dish Rotating Platform (UK) Prospective on Vanguard Total Knee System (CR and PS) (US) Prospective on Vanguard (UK) The England and Wales National Joint Registry (UKNJR) Australian National Joint Registry () Swedish Knee Arthroplasty Register (SKAR) Prospective Controlled on Vanguard Deep Dish Rotating Platform (France) Type No. of Cases Fixed Mobile Suitability Contribution Pre-market Registry Raw Data Annual Report Annual Report 70 CR, PS D1,A1,P1,T1 T4,O1,F1,P1 43 PS, CR D1,A1,P1,T3 T2,O3,F1,P1 600 PS D1,A1,P1,T3 T2,O3,F1,P1 265 PS Highflex RP D1,A1,P1,T3 T1,O3,F1,P1 300 CR DDRP D1,A1,P1,T3 T1,O3,F1,P1 81 CR DDRP D1,A1,P1,T3 T1,O3,F1,P1 357 CR, PS D1,A1,P1,T3 T2,O3,F1,P1 1104 CR, PS D1,A1,P1,T1 T2,O1,F1,P1 6659 CR, PS DDRP, VG ROCC D1,T1 T4,O1,F1,P1 4009 ALL ALL D1,T1 T4,O1,F1,P1 973 ALL ALL D1,T1 T4,O1,F1,P2 120 DDRP D1,A1,P1,T3 T2,O1,F1,P1 19 Danish Knee Register Registry Data 2681 CR D1,T1 T4,O1,F1,P1 20 21 New Zealand National Joint Registry 10 year Report Prospective on Vanguard Deep Dish Rotating Platform Knee (IDE Feasibility US) Registry Report 237 CR D1,T1 T4,O1,F1,P1 Pre-market 41 DDRP D1,A1,P1,T3 T2,O3,F1,P1 10 A Systematic Review on Performance of the Vanguard Complete Knee System
References 1. Biomet Comparison of MIS/Usual Technique for Vanguard (DS1) 2. Biomet Regenerex Tibial Tray Multi-center Data Collection (DS4) 3. Schroer Vanguard MIS Approach (DS6) 4. Biomet Korea Vanguard (DS7) 5. Biomet Vanguard DDRP IDE (DS9) 6. Biomet UK Vanguard DDRP (DS10) 7. Biomet Vanguard (DS11) 8. Biomet UK Vanguard (DS12) 9. The New England and Wales National Joint Registry Data Extract (DS14) 10. Australian National Joint Registry Annual Report (DS15) 11. Swedish Knee Arthroplasty Annual Report (DS16) 12. Biomet France Vanguard (DS17) 13. Danish Knee Registry (DS19, DS22) 14. New Zealand National Joint Registry 10 years 15. Biomet Vanguard DDRP IDE Feasibility (DS21) 16. Ritter, M. The Anatomical Graduated Component Total Knee Replacement: A Long-Term Evaluation with 20-year Survival Analysis. The Journal of Bone and Joint Surgery. 91-B(6):745 49, 2009. 17. Lombardi, A. et al. An Algorithm for the Posterior Cruciate Ligament In Total Knee Arthroplasty. Clinical Orthopaedics and Related Research. 392:75-87, 2001. 18. Bassett, R. Results of 1,000 Performance Knees Cementless Versus Cemented Fixation. The Journal of Arthroplasty. 13(4):409-13, 1998. 19. Sutton A. et al. Methods for Meta-Analysis in Medical Research. John Wiley and Sons. March 2002. Genesis is a trademark of Smith & Nephew. NexGen is a trademark of Zimmer, Inc. P.F.C. Sigma is a trademark of DePuy Orthopaedics. Triathlon is a trademark of Stryker Howmedica Osteonics Corp. All trademarks herein are the property of Biomet, Inc. or its subsidiaries unless otherwise indicated. This material is intended for the sole use and benefit of the Biomet sales force and physicians. It is not to be redistributed, duplicated or disclosed without the express written consent of Biomet. 11 A Systematic Review on Performance of the Vanguard Complete Knee System
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