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Use of National Joint Registries to Evaluate a New Knee Arthroplasty Design
The Journal of Arthroplasty xxx (2019) 1e4
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Use of National Joint Registries to Evaluate a New Knee Arthroplasty Design Edward M. Vasarhelyi, MD, MSc, FRCSC *, Stephen M. Petis, MD, MSc, FRCSC Department of Orthopedic Surgery, London Health Sciences Center, London, Ontario, Canada
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 July 2019 Received in revised form 24 August 2019 Accepted 12 September 2019 Available online xxx
Background: The introduction of new technology in joint replacement surgery requires close monitoring to identify early successes and failures. This monitoring can be effectively performed through the analysis of registry data and radiostereometric analysis studies. This study examined the revision rates of a contemporary knee system for total knee arthroplasty (TKA) using National Joint Replacement Registries. Methods: A review of the literature was performed to identify comparative studies and registry databases reporting the revision rates of a specific contemporary knee design between 2013 and 2018. The total number of TKA cases performed using this implant was recorded. The latest follow-up or duration of monitoring through a registry database was used to report implant survivorship. Results: There were 4 registry databases and 1 comparative study reporting the revision rates of the contemporary knee system. A total of 41,483 cases were identified with a follow-up range of 1.5-5.0 years. The all-cause revision rate ranged from 0.7% to 2.5% at latest follow-up. This was comparable to all-cause revision rates of other knee systems reported in the registries, ranging from 0.8% to 5.6% over similar follow-up periods. Conclusions: Evaluation of data from multiple national joint registries demonstrated the revision rate for this contemporary knee system to be comparable to other TKA systems at latest follow-up. None of the registries have identified any concerning rates of revision compared to other devices at this length of follow-up. National Joint Registries are an important resource in evaluating the short-term, mid-term, and long-term results of new implant designs introduced to the market. © 2019 Elsevier Inc. All rights reserved.
Keywords: primary knee arthroplasty registry revision
Total knee arthroplasty (TKA) is an effective surgical procedure to treat arthritis of the knee after failed nonoperative management. Implant survivorship free of revision from any cause is predicated on patient factors, surgical technique, implant selection, and postoperative rehabilitation. There are multiple modes of implant failure after TKA. Commonly cited etiologies include infection, aseptic loosening, instability, and pain [1,2]. Early aseptic loosening within the first year following TKA is rare. This is due to failure of fixation at the bone-cement or cement-implant interfaces. Contemporary TKA implant designs have worked toward improving patient function and reported outcomes, while reducing all-cause failure rates. One
One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2019.09.018. * Reprint requests: Edward M. Vasarhelyi, MD, FRCSC, Department of Orthopedic Surgery, London Health Sciences Center, 339 Windermere Road, London, Ontario, Canada, N6A 5A5. https://doi.org/10.1016/j.arth.2019.09.018 0883-5403/© 2019 Elsevier Inc. All rights reserved.
such system was recently introduced, which has incorporated a reducing femoral radius of curvature through range of motion, increased modularity, and low-profile femoral trochlear design. Despite these innovative changes, a report has suggested early tibial baseplate loosening with this system. Bonutti et al [3] reported 15 cases of tibial loosening at a mean time from surgery of 19 months. However, this study had several limitations, including an unknown denominator of treated cases, unclear radiographic and intraoperative assessment of aseptic loosening, and concern regarding selection bias from a newly created database. The failure or success of new innovation cannot be defined by isolated shortcomings or short-term successes. There are many forms of bias that limit case series reports, especially where failures are presented without knowledge of the denominator of treated cases (as in retrieval studies and collections of failed cases from numerous sources). On the other hand, National Joint Registries (NJRs) disseminate information that emulates real-world practice in a dynamic time frame. The purpose of this study is to perform a literature and registry data review to examine the revision rate using a contemporary knee system at latest follow-up.
2
E.M. Vasarhelyi, S.M. Petis / The Journal of Arthroplasty xxx (2019) 1e4
Materials and Methods A critical review of the literature was performed to identify studies or registry data examining the incidence of aseptic loosening following TKA using the Attune system (DePuy, Warsaw, IN). A comprehensive literature search was performed using PubMed and MEDLINE database search engines. The keywords “knee,” “arthroplasty,” “Attune,” and “revision” were used to identify studies examining implant survivorship using this knee design. Comparative studies dating from April 2013 to December 2018 were included in our review, corresponding with the release of this implant. International registry data were also reviewed to identify implant survivorship using this knee system. Registry data provide generalizable data about the performance of various implant designs, as they capture information from various patient demographics and from multiple centers and surgeons. These data help to eliminate biases observed in single-institution trials. Registries printed in English were reviewed. The total number of TKA cases performed, as well as the number of revision cases, was reported for registries that outlined implant survivorship for specific knee designs. The data presented were descriptive, including means and percentages when applicable. We recorded the mean follow-up time or number of years postoperative for which the revision rates were reported. The revision rates were reported separately for differing levels of constraint (ie, cruciate-retaining [CR], posterior stabilized [PS]). The 95% confidence intervals (CIs) for cumulative revision rates were reported when available.
Results Following a detailed review of the literature, we identified 4 registries and 1 scientific study that reported cumulative revision rates using this contemporary knee system. The identified registries were the Australian Orthopedic Association National Joint Replacement Registry (AOANJRR) [4], the Michigan Arthroplasty Registry Collaborative Quality Initiative [5], The New Zealand Joint Registry [6], and the NJR from the United Kingdom [7]. Several other registries were reviewed (ie, American Joint Replacement Registry, Canadian Joint Replacement Registry, Swedish Knee Arthroplasty Register, etc.), but these registries did not report implant survivorship for specific implant designs. The AOANJRR is a prospectively maintained joint registry entering its 20th year. Established in 1999, the 2018 review provided a survivorship analysis of over 1 million joint arthroplasties. The range of cumulative percent revision rates for cemented TKA systems with at least 400 cases was 0.8%-5.6% at 3 years of followup. For this specific knee system, the cumulative percent revision rate was 2.3% for CR and 1.3% for PS knees at 3 years [4]. The Michigan Arthroplasty Registry Collaborative Quality Initiative began in 2011 to improve the delivery and results of hip and knee arthroplasty in the state of Michigan. The registry prospectively collects data about patient demographics, implant selection, revisions, and complications from 65 healthcare facilities in Michigan. The cumulative percent revision risk for TKA systems with at least 500 cases performed ranged from 0.8% to 4.4% at 3year follow-up. The cumulative percent revision risk for this specific system was 2.5% at 3 years [5]. The New Zealand Joint Registry was established in 1999 and has registered over 100,000 TKAs. This registry reports revision rates using observed component years, which takes into account mean follow-up, as well as the number of cases performed for each implant design. The revision rate for cemented TKAs with at least 50 registered cases ranged from 0.16 to 1.61/100 component-years. The revision rate for this knee system was 0.65/100 component-years [6].
The NJR from the United Kingdom released its 15th annual report in 2018. An auditing system is in place to not only capture cases inputted automatically, but also captures data from hospital systems that were not entered through automation. Data are reported for knee systems with at least 1000 cases performed. The cumulative revision rate ranged from 1.3% to 3.3% at 3-year follow-up. The reported revision rate for this knee system was 1.5% at 3 years [7]. A total of 41,483 TKA cases using this specific knee system were captured from our review. There were 23,676 (57%) CR knees, 11,175 (27%) PS knees, and 6632 (16%) had an unknown bearing type. The follow-up or years reported for implant survivorship ranged from 1.5 to 5.0 years. The revision rate for this system ranged from 0.7% to 2.5% at latest follow-up or for the years reported by each registry or clinical study (Table 1). In addition to the published registry data, the AOANJRR produces an Automated Industry Report System. The value of this is an ability to review knee systems based on their reason for revision and serves as an in-depth examination of the usage of specific implants. Two reports have been produced for this system, reporting on the CR and PS knee designs, respectively [9,10]. The 4-year cumulative revision rate for all knee designs is 3.1% (95% CI 3.1-3.2), which is higher than both this specific CR knee system 2.0% (95% CI 1.6-2.3) (hazard ratio 0.65 (0.48, 0.87), P ¼ .003) [9], and this specific PS knee system 1.8% (95% CI 1.4-2.4) (hazard ratio 0.61 (0.48, 0.78), P < .001) [10]. Similar to the New Zealand Registry, this CR knee system has a revision rate of 0.61/100 component-years [9] and the PS knee system has a revision rate of 0.53/100 component-years [10]. A total of 11,735 CR knees using this specific system are tracked in the AOANJRR registry, and at 5 years, the most common reason for revision is infection, accounting for 65 cases (0.7%). A total of 19 cases (0.3%) were revised for loosening [9]. A total of 5263 PS knees using this specific system are tracked in the registry, and similarly show infection as the most common reason for revision in 25 cases (0.6%), followed by loosening in 12 cases (0.5%) [10]. These numbers compare favorably to all other knee systems with a reported incidence of infection of 0.9% and 0.8% of loosening [9,10]. Discussion Our study reports a revision rate of 0.7%-2.5% at 1.5-5.0 years of follow-up using a contemporary knee system in over 40,000 cases. These revision rates are similar to other TKA systems reported in
Table 1 Summary of Study and Registry Reported Attune Revision Rates. Study or Registry
Number of TKAs Number of Follow-Up Implant Revision or Years Revised Using Attune Reported Rate (95% CI) Attune System TKAs
Australian Orthopedic Association National Joint Replacement Registry [4] Michigan Arthroplasty Registry Collaborative Quality Initiative [5] The New Zealand Joint Registry [6] National Joint Registry (United Kingdom) [7] Staats et al [8]
CR Attune 8849 109 PS Attune 4034 37
3 3
2.3 (1.9-2.9) 1.3 (0.9-1.8)
6356
91
3
2.5 (2.0-3.2)
CR 3724 PS 2042 CR fixed 9598 CR mobile 1505 PS fixed 5099 276
47 16 NR NR NR 3
1.8 1.5 3 3 3 3
1.2 0.8 1.8 0.7 1.3 1.1
(NR)a (NR)a (1.4-2.5) (0.3-1.7) (0.8-2.0) (NR)
TKA, total knee arthroplasty; CI, confidence interval; CR, cruciate retaining; PS, posterior stabilized; NR, not reported. a These values were calculated from rate/100 component-year data presented in the registry.
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the registry or literature data. However, because the exact etiology of revision cases for specific implant designs is not reported through most registry data, we cannot comment on the mechanism of early failures using this knee system in the registries other than the AOANJRR. On the subset of patients reported in the AOANJRR, which comprises a total of 16,998 primary TKAs using this system, there were a total of 31 knees (0.2%) revised for loosening. This has a lower, nonoverlapping, 95% CI when compared to all other knees revised for loosening (0.8%) reported in the AOANJRR. Based on these registry data, it can be reasonably concluded that loosening is a rare occurrence for this specific knee system. The registry does not elucidate whether these cases are isolated tibial or femoral components, or both, thereby leaving the possibility that the incidence of tibial loosening is lower than 0.2%. The study by Bonutti et al reported 15 cases of debonding of the tibial baseplate from cement using this knee system. Unfortunately, the paper does not report over how many total cases these revisions occurred. This is an important limitation, as it would elucidate the frequency of these events and classify them as common or rare [11]. Therefore, the revision rate over the mean time to revision surgery (19 months) cannot be compared to the cumulative revision rates reported in the registry data included in our study. The generalizability of this data is limited, as the failures are reported from 3e community hospitals. There was no report of case volumes for the surgeons, as acute failures may occur early in the learning curve after introducing any new technology. The Bonutti et al study also raises concerns regarding the presence of radiolucent lines on early postoperative radiographs after a TKA using this knee system. Radiolucent lines have been reported previously using this knee system, and these authors suggest that it is likely due to surgical technique rather than implant-related failure [8]. The appearance of radiolucent lines can also be dependent on radiographic technique (limb rotation, sagittal alignment) and surgical technique if the tibial/femoral osteotomies are imperfect. Finally, insertion of the polyethylene and loading of the knee prior to cement hardening is variable as part of each surgeon’s workflow and could impact cement interdigitation. Implant fixation using this specific knee system has been examined using radiostereometric analysis (RSA). This technique is a commonly employed method of examining the short to long-term risk of aseptic failure of orthopedic implants [12]. Two-year RSA results have been shown to be predictive of medium to long-term fixation. Turgeon et al [13] studied maximum total point motion (MTPM) of this knee system at short-term follow-up using RSA. They reported a mean MTPM of 0.08 mm between 12 and 24 months, which is well below the reported threshold of 0.20 mm predicting early aseptic failures [14,15]. This mean MTPM is below or comparable with other contemporary cemented TKA systems examined with RSA, with MTPM ranges reported from 0.27 to 0.54 at 12 months postoperatively [16e18]. Although longer term follow-up is needed to ensure acceptable revision rates for longterm aseptic loosening, this RSA study demonstrates excellent early fixation with this specific knee system. Early aseptic loosening with tibial implant-cement interface debonding has been reported previously using other various total knee systems [19,20]. The etiology of these acute failures is likely multifactorial. Implant malalignment can lead to early failure due to abnormal stress distribution across various interfaces [21]. Cementing technique and cement composition can impact the longevity and quality of implant fixation [19,22]. Implant design, including surface composition, can affect implant bonding to the cement [18]. Previous studies have also shown that pull-off strength does not correlate with the mode of failure at the bonecement or implant-cement interface [23]. Care should be taken when drawing conclusions about acute failures from limited
3
retrospective case series, as controlling for multiple variables that could contribute to implant failure is not possible. Our study does have limitations. The majority of the data presented come from registry data. These data can be limited by compliance with data submission, thoroughness of data input, and what data are actually analyzed. The data presented also fail to comment on patient-reported outcome measures, which are another set of data points often not reported by registry databases. Finally, with the exception of the AOANJRR which reports mode of failure, review of most other registry data does not specify the etiology of failure, thus in some of the national registries we cannot definitively conclude that this contemporary knee system has higher or lower failures specifically owing to aseptic loosening. This study demonstrates revision rates using this contemporary knee system across several national and state registries in over 40,000 TKAs that are comparable to other knee designs at latest follow-up. When specifically looking at revision for loosening, there is registry evidence to suggest that this system performs similarly to other available knee systems. In addition, the published RSA results also demonstrate encouraging findings regarding the stability of this implant. Future work should continue to monitor the long-term implant survivorship through registry and comparative studies to ensure that these results continue to be comparable to existing, well-performing implants. Joint registry evaluation is a powerful tool that should be considered when evaluating the shortterm and mid-term results of all new designs introduced to the market.
References [1] Thiele K, Perka C, Matziolis G, Mayr H, Sostheim M, Hube R. Current failure mechanisms after knee arthroplasty have changed: polyethylene wear is less common in revision surgery. J Bone Joint Surg Am 2015;97:715e20. [2] Sharkey P, Lichstein P, Shen C, Tokarski A, Parvizi J. Why are total knee arthroplasties failing todaydhas anything changed after 10 years. J Arthroplasty 2014;29:1774e8. [3] Bonutti P, Khlopas A, Chughtai M, Cole C, Gwam C, Harwin S, et al. Unusually high rate of early failure of tibial component in ATTUNE total knee arthroplasty system at implant-cement interface. J Knee Surg 2017;30:435e9. [4] Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2018 Annual Report. Adelaide: AOA; 2018. [5] Hughes RE, Zheng H, Hallstrom BR. Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) Report: 2012-2017. Ann Arbor: University of Michigan; 2018. [6] McKie J, Hobbs T, Frampton C. The New Zealand Joint Registry 19 year report. https://nzoa.org.nz/system/files/DH8152_NZJR_2018_Report_v6_4Decv18. pdf; 2018. [7] Reed M, editor. 15th Annual report 2018: National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man; 2018. http://www.njrreports.or g.uk/Portals/0/PDFdownloads/NJR%2015th%20Annual%20Report%202018.pdf. [8] Staats K, Wannmacher T, Weihs V, Koller U, Kubista B, Windhager R. Modern cemented total knee arthroplasty design shows a higher incidence of radiolucent lines compared to its predecessor. Knee Surg Sports Traumatol Arthrosc 2019;27:1148e55. [9] No Author Listed. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), Automated Industry Report System (AIRS), ID No. 823 for DePuy Synthes, ATTUNE CR/ATTUNE total knee (procedures from 1 September 1999 e 8 January 2019). Adelaide: AOA; 2019. p. 1e14. [10] No Author Listed. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), Automated Industry Report System (AIRS), ID No. 824 for DePuy Synthes, ATTUNE PS/ATTUNE total knee (procedures from 1 September 1999 e 8 January 2019). Adelaide: AOA; 2019. p. 1e14. [11] Mont MA. Isolated group of failures without denominator. J Knee Surg 2018;31:591e2. [12] Nelissen R, Pijls B, Karrholm J, Malchau H, Nieuwenhuijse M, Valstar E. RSA and registries: the quest for phased introduction of new implants. J Bone Joint Surg Am 2011;93:62e5. [13] Turgeon T, Gascoyne T, Laende E, Dunbar M, Bohm E, Richardson C. The assessment of the stability of the tibial component of a novel knee arthroplasty system using radiostereometric analysis. Bone Joint J 2018;100: 1579e84. [14] Ryd L, Albrektsson B, Carlsson L, Dansgard F, Herberts P, Lindstrand A, et al. Roentgen stereophotogrammetric analysis as a predictor of mechanical loosening of knee prostheses. J Bone Joint Surg Br 1995;77:377e83.
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[15] Gudnason A, Adalberth G, Nilsson K, Hailer N. Tibial component rotation around the transverse axis measured by radiostereometry predicts aseptic loosening better than maximal total point motion. Acta Orthop 2017;88: 282e7. [16] Teeter M, Thoren J, Yuan X, McCalden R, MacDonald S, Lanting B, et al. Migration of a cemented fixed-bearing, polished titanium baseplate (Genesis II) at ten years: a radiostereometric analysis. Bone Joint J 2016;98: 616e21. [17] Petursson G, Fenstad A, Gothesen O, Haugan K, Dyrhovden G, Hallan G, et al. Similar migration in computer-assisted and conventional total knee arthroplasty. Acta Orthop 2017;88:166e72. [18] van Hamersveld K, Marang-van de Mheen P, Tsonaka R, Valstar E, ToksvigLarsen S. Fixation and clinical outcome of uncemented peri-apatite-coated versus cemented total knee arthroplasty: five-year follow-up of a randomised controlled trial using radiostereometric analysis (RSA). Bone Joint J 2017;99:1467e76.
[19] Kopinski J, Aggarwal A, Nunley R, Barrack R, Nam D. Failure at the tibial cement-implant interface with the use of high-viscosity cement in total knee arthroplasty. J Arthroplasty 2016;31:2579e82. [20] Arsoy D, Pagnano M, Lewallen D, Hanssen A, Sierra R. Aseptic tibial debonding as a cause of early failure in a modern total knee arthroplasty design. Clin Orthop Relat Res 2013;471:94e101. [21] Parratte S, Pagnano M, Trousdale R, Berry D. Effect of postoperative mechanical axis alignment on the fifteen-year survival of modern, cemented total knee replacements. J Bone Joint Surg Am 2010;92:2143e9. [22] Dunne N, Hill J, McAfee P, Kirkpatrick R, Patrick S, Tunney M. Incorporation of large amounts of gentamicin sulphate into acrylic bone cement: effect on handling and mechanical properties, antibiotic release, and biofilm formation. Proc Inst Mech Eng H 2008;222:355e65. [23] Uhlenbrock A, Puschel V, Puschel K, Morlock M, Bishop N. Influence of time insitu and implant type on fixation strength of cemented tibial traysda post mortem retrieval analysis. Clin Biomech 2012;27:929e35.
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Use of National Joint Registries to Evaluate a New Knee Arthroplasty Design Edward M. Vasarhelyi, MD, MSc, FRCSC *, Stephen M. Petis, MD, MSc, FRCSC Department of Orthopedic Surgery, London Health Sciences Center, London, Ontario, Canada
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 July 2019 Received in revised form 24 August 2019 Accepted 12 September 2019 Available online xxx
Background: The introduction of new technology in joint replacement surgery requires close monitoring to identify early successes and failures. This monitoring can be effectively performed through the analysis of registry data and radiostereometric analysis studies. This study examined the revision rates of a contemporary knee system for total knee arthroplasty (TKA) using National Joint Replacement Registries. Methods: A review of the literature was performed to identify comparative studies and registry databases reporting the revision rates of a specific contemporary knee design between 2013 and 2018. The total number of TKA cases performed using this implant was recorded. The latest follow-up or duration of monitoring through a registry database was used to report implant survivorship. Results: There were 4 registry databases and 1 comparative study reporting the revision rates of the contemporary knee system. A total of 41,483 cases were identified with a follow-up range of 1.5-5.0 years. The all-cause revision rate ranged from 0.7% to 2.5% at latest follow-up. This was comparable to all-cause revision rates of other knee systems reported in the registries, ranging from 0.8% to 5.6% over similar follow-up periods. Conclusions: Evaluation of data from multiple national joint registries demonstrated the revision rate for this contemporary knee system to be comparable to other TKA systems at latest follow-up. None of the registries have identified any concerning rates of revision compared to other devices at this length of follow-up. National Joint Registries are an important resource in evaluating the short-term, mid-term, and long-term results of new implant designs introduced to the market. © 2019 Elsevier Inc. All rights reserved.
Keywords: primary knee arthroplasty registry revision
Total knee arthroplasty (TKA) is an effective surgical procedure to treat arthritis of the knee after failed nonoperative management. Implant survivorship free of revision from any cause is predicated on patient factors, surgical technique, implant selection, and postoperative rehabilitation. There are multiple modes of implant failure after TKA. Commonly cited etiologies include infection, aseptic loosening, instability, and pain [1,2]. Early aseptic loosening within the first year following TKA is rare. This is due to failure of fixation at the bone-cement or cement-implant interfaces. Contemporary TKA implant designs have worked toward improving patient function and reported outcomes, while reducing all-cause failure rates. One
One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2019.09.018. * Reprint requests: Edward M. Vasarhelyi, MD, FRCSC, Department of Orthopedic Surgery, London Health Sciences Center, 339 Windermere Road, London, Ontario, Canada, N6A 5A5. https://doi.org/10.1016/j.arth.2019.09.018 0883-5403/© 2019 Elsevier Inc. All rights reserved.
such system was recently introduced, which has incorporated a reducing femoral radius of curvature through range of motion, increased modularity, and low-profile femoral trochlear design. Despite these innovative changes, a report has suggested early tibial baseplate loosening with this system. Bonutti et al [3] reported 15 cases of tibial loosening at a mean time from surgery of 19 months. However, this study had several limitations, including an unknown denominator of treated cases, unclear radiographic and intraoperative assessment of aseptic loosening, and concern regarding selection bias from a newly created database. The failure or success of new innovation cannot be defined by isolated shortcomings or short-term successes. There are many forms of bias that limit case series reports, especially where failures are presented without knowledge of the denominator of treated cases (as in retrieval studies and collections of failed cases from numerous sources). On the other hand, National Joint Registries (NJRs) disseminate information that emulates real-world practice in a dynamic time frame. The purpose of this study is to perform a literature and registry data review to examine the revision rate using a contemporary knee system at latest follow-up.
2
E.M. Vasarhelyi, S.M. Petis / The Journal of Arthroplasty xxx (2019) 1e4
Materials and Methods A critical review of the literature was performed to identify studies or registry data examining the incidence of aseptic loosening following TKA using the Attune system (DePuy, Warsaw, IN). A comprehensive literature search was performed using PubMed and MEDLINE database search engines. The keywords “knee,” “arthroplasty,” “Attune,” and “revision” were used to identify studies examining implant survivorship using this knee design. Comparative studies dating from April 2013 to December 2018 were included in our review, corresponding with the release of this implant. International registry data were also reviewed to identify implant survivorship using this knee system. Registry data provide generalizable data about the performance of various implant designs, as they capture information from various patient demographics and from multiple centers and surgeons. These data help to eliminate biases observed in single-institution trials. Registries printed in English were reviewed. The total number of TKA cases performed, as well as the number of revision cases, was reported for registries that outlined implant survivorship for specific knee designs. The data presented were descriptive, including means and percentages when applicable. We recorded the mean follow-up time or number of years postoperative for which the revision rates were reported. The revision rates were reported separately for differing levels of constraint (ie, cruciate-retaining [CR], posterior stabilized [PS]). The 95% confidence intervals (CIs) for cumulative revision rates were reported when available.
Results Following a detailed review of the literature, we identified 4 registries and 1 scientific study that reported cumulative revision rates using this contemporary knee system. The identified registries were the Australian Orthopedic Association National Joint Replacement Registry (AOANJRR) [4], the Michigan Arthroplasty Registry Collaborative Quality Initiative [5], The New Zealand Joint Registry [6], and the NJR from the United Kingdom [7]. Several other registries were reviewed (ie, American Joint Replacement Registry, Canadian Joint Replacement Registry, Swedish Knee Arthroplasty Register, etc.), but these registries did not report implant survivorship for specific implant designs. The AOANJRR is a prospectively maintained joint registry entering its 20th year. Established in 1999, the 2018 review provided a survivorship analysis of over 1 million joint arthroplasties. The range of cumulative percent revision rates for cemented TKA systems with at least 400 cases was 0.8%-5.6% at 3 years of followup. For this specific knee system, the cumulative percent revision rate was 2.3% for CR and 1.3% for PS knees at 3 years [4]. The Michigan Arthroplasty Registry Collaborative Quality Initiative began in 2011 to improve the delivery and results of hip and knee arthroplasty in the state of Michigan. The registry prospectively collects data about patient demographics, implant selection, revisions, and complications from 65 healthcare facilities in Michigan. The cumulative percent revision risk for TKA systems with at least 500 cases performed ranged from 0.8% to 4.4% at 3year follow-up. The cumulative percent revision risk for this specific system was 2.5% at 3 years [5]. The New Zealand Joint Registry was established in 1999 and has registered over 100,000 TKAs. This registry reports revision rates using observed component years, which takes into account mean follow-up, as well as the number of cases performed for each implant design. The revision rate for cemented TKAs with at least 50 registered cases ranged from 0.16 to 1.61/100 component-years. The revision rate for this knee system was 0.65/100 component-years [6].
The NJR from the United Kingdom released its 15th annual report in 2018. An auditing system is in place to not only capture cases inputted automatically, but also captures data from hospital systems that were not entered through automation. Data are reported for knee systems with at least 1000 cases performed. The cumulative revision rate ranged from 1.3% to 3.3% at 3-year follow-up. The reported revision rate for this knee system was 1.5% at 3 years [7]. A total of 41,483 TKA cases using this specific knee system were captured from our review. There were 23,676 (57%) CR knees, 11,175 (27%) PS knees, and 6632 (16%) had an unknown bearing type. The follow-up or years reported for implant survivorship ranged from 1.5 to 5.0 years. The revision rate for this system ranged from 0.7% to 2.5% at latest follow-up or for the years reported by each registry or clinical study (Table 1). In addition to the published registry data, the AOANJRR produces an Automated Industry Report System. The value of this is an ability to review knee systems based on their reason for revision and serves as an in-depth examination of the usage of specific implants. Two reports have been produced for this system, reporting on the CR and PS knee designs, respectively [9,10]. The 4-year cumulative revision rate for all knee designs is 3.1% (95% CI 3.1-3.2), which is higher than both this specific CR knee system 2.0% (95% CI 1.6-2.3) (hazard ratio 0.65 (0.48, 0.87), P ¼ .003) [9], and this specific PS knee system 1.8% (95% CI 1.4-2.4) (hazard ratio 0.61 (0.48, 0.78), P < .001) [10]. Similar to the New Zealand Registry, this CR knee system has a revision rate of 0.61/100 component-years [9] and the PS knee system has a revision rate of 0.53/100 component-years [10]. A total of 11,735 CR knees using this specific system are tracked in the AOANJRR registry, and at 5 years, the most common reason for revision is infection, accounting for 65 cases (0.7%). A total of 19 cases (0.3%) were revised for loosening [9]. A total of 5263 PS knees using this specific system are tracked in the registry, and similarly show infection as the most common reason for revision in 25 cases (0.6%), followed by loosening in 12 cases (0.5%) [10]. These numbers compare favorably to all other knee systems with a reported incidence of infection of 0.9% and 0.8% of loosening [9,10]. Discussion Our study reports a revision rate of 0.7%-2.5% at 1.5-5.0 years of follow-up using a contemporary knee system in over 40,000 cases. These revision rates are similar to other TKA systems reported in
Table 1 Summary of Study and Registry Reported Attune Revision Rates. Study or Registry
Number of TKAs Number of Follow-Up Implant Revision or Years Revised Using Attune Reported Rate (95% CI) Attune System TKAs
Australian Orthopedic Association National Joint Replacement Registry [4] Michigan Arthroplasty Registry Collaborative Quality Initiative [5] The New Zealand Joint Registry [6] National Joint Registry (United Kingdom) [7] Staats et al [8]
CR Attune 8849 109 PS Attune 4034 37
3 3
2.3 (1.9-2.9) 1.3 (0.9-1.8)
6356
91
3
2.5 (2.0-3.2)
CR 3724 PS 2042 CR fixed 9598 CR mobile 1505 PS fixed 5099 276
47 16 NR NR NR 3
1.8 1.5 3 3 3 3
1.2 0.8 1.8 0.7 1.3 1.1
(NR)a (NR)a (1.4-2.5) (0.3-1.7) (0.8-2.0) (NR)
TKA, total knee arthroplasty; CI, confidence interval; CR, cruciate retaining; PS, posterior stabilized; NR, not reported. a These values were calculated from rate/100 component-year data presented in the registry.
E.M. Vasarhelyi, S.M. Petis / The Journal of Arthroplasty xxx (2019) 1e4
the registry or literature data. However, because the exact etiology of revision cases for specific implant designs is not reported through most registry data, we cannot comment on the mechanism of early failures using this knee system in the registries other than the AOANJRR. On the subset of patients reported in the AOANJRR, which comprises a total of 16,998 primary TKAs using this system, there were a total of 31 knees (0.2%) revised for loosening. This has a lower, nonoverlapping, 95% CI when compared to all other knees revised for loosening (0.8%) reported in the AOANJRR. Based on these registry data, it can be reasonably concluded that loosening is a rare occurrence for this specific knee system. The registry does not elucidate whether these cases are isolated tibial or femoral components, or both, thereby leaving the possibility that the incidence of tibial loosening is lower than 0.2%. The study by Bonutti et al reported 15 cases of debonding of the tibial baseplate from cement using this knee system. Unfortunately, the paper does not report over how many total cases these revisions occurred. This is an important limitation, as it would elucidate the frequency of these events and classify them as common or rare [11]. Therefore, the revision rate over the mean time to revision surgery (19 months) cannot be compared to the cumulative revision rates reported in the registry data included in our study. The generalizability of this data is limited, as the failures are reported from 3e community hospitals. There was no report of case volumes for the surgeons, as acute failures may occur early in the learning curve after introducing any new technology. The Bonutti et al study also raises concerns regarding the presence of radiolucent lines on early postoperative radiographs after a TKA using this knee system. Radiolucent lines have been reported previously using this knee system, and these authors suggest that it is likely due to surgical technique rather than implant-related failure [8]. The appearance of radiolucent lines can also be dependent on radiographic technique (limb rotation, sagittal alignment) and surgical technique if the tibial/femoral osteotomies are imperfect. Finally, insertion of the polyethylene and loading of the knee prior to cement hardening is variable as part of each surgeon’s workflow and could impact cement interdigitation. Implant fixation using this specific knee system has been examined using radiostereometric analysis (RSA). This technique is a commonly employed method of examining the short to long-term risk of aseptic failure of orthopedic implants [12]. Two-year RSA results have been shown to be predictive of medium to long-term fixation. Turgeon et al [13] studied maximum total point motion (MTPM) of this knee system at short-term follow-up using RSA. They reported a mean MTPM of 0.08 mm between 12 and 24 months, which is well below the reported threshold of 0.20 mm predicting early aseptic failures [14,15]. This mean MTPM is below or comparable with other contemporary cemented TKA systems examined with RSA, with MTPM ranges reported from 0.27 to 0.54 at 12 months postoperatively [16e18]. Although longer term follow-up is needed to ensure acceptable revision rates for longterm aseptic loosening, this RSA study demonstrates excellent early fixation with this specific knee system. Early aseptic loosening with tibial implant-cement interface debonding has been reported previously using other various total knee systems [19,20]. The etiology of these acute failures is likely multifactorial. Implant malalignment can lead to early failure due to abnormal stress distribution across various interfaces [21]. Cementing technique and cement composition can impact the longevity and quality of implant fixation [19,22]. Implant design, including surface composition, can affect implant bonding to the cement [18]. Previous studies have also shown that pull-off strength does not correlate with the mode of failure at the bonecement or implant-cement interface [23]. Care should be taken when drawing conclusions about acute failures from limited
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retrospective case series, as controlling for multiple variables that could contribute to implant failure is not possible. Our study does have limitations. The majority of the data presented come from registry data. These data can be limited by compliance with data submission, thoroughness of data input, and what data are actually analyzed. The data presented also fail to comment on patient-reported outcome measures, which are another set of data points often not reported by registry databases. Finally, with the exception of the AOANJRR which reports mode of failure, review of most other registry data does not specify the etiology of failure, thus in some of the national registries we cannot definitively conclude that this contemporary knee system has higher or lower failures specifically owing to aseptic loosening. This study demonstrates revision rates using this contemporary knee system across several national and state registries in over 40,000 TKAs that are comparable to other knee designs at latest follow-up. When specifically looking at revision for loosening, there is registry evidence to suggest that this system performs similarly to other available knee systems. In addition, the published RSA results also demonstrate encouraging findings regarding the stability of this implant. Future work should continue to monitor the long-term implant survivorship through registry and comparative studies to ensure that these results continue to be comparable to existing, well-performing implants. Joint registry evaluation is a powerful tool that should be considered when evaluating the shortterm and mid-term results of all new designs introduced to the market.
References [1] Thiele K, Perka C, Matziolis G, Mayr H, Sostheim M, Hube R. Current failure mechanisms after knee arthroplasty have changed: polyethylene wear is less common in revision surgery. J Bone Joint Surg Am 2015;97:715e20. [2] Sharkey P, Lichstein P, Shen C, Tokarski A, Parvizi J. Why are total knee arthroplasties failing todaydhas anything changed after 10 years. J Arthroplasty 2014;29:1774e8. [3] Bonutti P, Khlopas A, Chughtai M, Cole C, Gwam C, Harwin S, et al. Unusually high rate of early failure of tibial component in ATTUNE total knee arthroplasty system at implant-cement interface. J Knee Surg 2017;30:435e9. [4] Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2018 Annual Report. Adelaide: AOA; 2018. [5] Hughes RE, Zheng H, Hallstrom BR. Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) Report: 2012-2017. Ann Arbor: University of Michigan; 2018. [6] McKie J, Hobbs T, Frampton C. The New Zealand Joint Registry 19 year report. https://nzoa.org.nz/system/files/DH8152_NZJR_2018_Report_v6_4Decv18. pdf; 2018. [7] Reed M, editor. 15th Annual report 2018: National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man; 2018. http://www.njrreports.or g.uk/Portals/0/PDFdownloads/NJR%2015th%20Annual%20Report%202018.pdf. [8] Staats K, Wannmacher T, Weihs V, Koller U, Kubista B, Windhager R. Modern cemented total knee arthroplasty design shows a higher incidence of radiolucent lines compared to its predecessor. Knee Surg Sports Traumatol Arthrosc 2019;27:1148e55. [9] No Author Listed. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), Automated Industry Report System (AIRS), ID No. 823 for DePuy Synthes, ATTUNE CR/ATTUNE total knee (procedures from 1 September 1999 e 8 January 2019). Adelaide: AOA; 2019. p. 1e14. [10] No Author Listed. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), Automated Industry Report System (AIRS), ID No. 824 for DePuy Synthes, ATTUNE PS/ATTUNE total knee (procedures from 1 September 1999 e 8 January 2019). Adelaide: AOA; 2019. p. 1e14. [11] Mont MA. Isolated group of failures without denominator. J Knee Surg 2018;31:591e2. [12] Nelissen R, Pijls B, Karrholm J, Malchau H, Nieuwenhuijse M, Valstar E. RSA and registries: the quest for phased introduction of new implants. J Bone Joint Surg Am 2011;93:62e5. [13] Turgeon T, Gascoyne T, Laende E, Dunbar M, Bohm E, Richardson C. The assessment of the stability of the tibial component of a novel knee arthroplasty system using radiostereometric analysis. Bone Joint J 2018;100: 1579e84. [14] Ryd L, Albrektsson B, Carlsson L, Dansgard F, Herberts P, Lindstrand A, et al. Roentgen stereophotogrammetric analysis as a predictor of mechanical loosening of knee prostheses. J Bone Joint Surg Br 1995;77:377e83.
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[15] Gudnason A, Adalberth G, Nilsson K, Hailer N. Tibial component rotation around the transverse axis measured by radiostereometry predicts aseptic loosening better than maximal total point motion. Acta Orthop 2017;88: 282e7. [16] Teeter M, Thoren J, Yuan X, McCalden R, MacDonald S, Lanting B, et al. Migration of a cemented fixed-bearing, polished titanium baseplate (Genesis II) at ten years: a radiostereometric analysis. Bone Joint J 2016;98: 616e21. [17] Petursson G, Fenstad A, Gothesen O, Haugan K, Dyrhovden G, Hallan G, et al. Similar migration in computer-assisted and conventional total knee arthroplasty. Acta Orthop 2017;88:166e72. [18] van Hamersveld K, Marang-van de Mheen P, Tsonaka R, Valstar E, ToksvigLarsen S. Fixation and clinical outcome of uncemented peri-apatite-coated versus cemented total knee arthroplasty: five-year follow-up of a randomised controlled trial using radiostereometric analysis (RSA). Bone Joint J 2017;99:1467e76.
[19] Kopinski J, Aggarwal A, Nunley R, Barrack R, Nam D. Failure at the tibial cement-implant interface with the use of high-viscosity cement in total knee arthroplasty. J Arthroplasty 2016;31:2579e82. [20] Arsoy D, Pagnano M, Lewallen D, Hanssen A, Sierra R. Aseptic tibial debonding as a cause of early failure in a modern total knee arthroplasty design. Clin Orthop Relat Res 2013;471:94e101. [21] Parratte S, Pagnano M, Trousdale R, Berry D. Effect of postoperative mechanical axis alignment on the fifteen-year survival of modern, cemented total knee replacements. J Bone Joint Surg Am 2010;92:2143e9. [22] Dunne N, Hill J, McAfee P, Kirkpatrick R, Patrick S, Tunney M. Incorporation of large amounts of gentamicin sulphate into acrylic bone cement: effect on handling and mechanical properties, antibiotic release, and biofilm formation. Proc Inst Mech Eng H 2008;222:355e65. [23] Uhlenbrock A, Puschel V, Puschel K, Morlock M, Bishop N. Influence of time insitu and implant type on fixation strength of cemented tibial traysda post mortem retrieval analysis. Clin Biomech 2012;27:929e35.