Why Are Total Knees Failing Today? Etiology of Total Knee Revision in 2010 and 2011
TL;DR: Revision knee data from six joint arthroplasty centers were compiled for 2010 and 2011 to determine mechanism of failure and time to failure, and polyethylene wear is not a leading failure mechanism and rarely presents before 15 years.
Abstract: Revision knee data from six joint arthroplasty centers were compiled for 2010 and 2011 to determine mechanism of failure and time to failure. Aseptic loosening was the predominant mechanism of failure (31.2%), followed by instability (18.7%), infection (16.2%), polyethylene wear (10.0%), arthrofibrosis (6.9%), and malalignment (6.6%). Mean time to failure was 5.9 years (range 10 days to 31 years). 35.3% of all revisions occurred less than 2 years after the index arthroplasty, 60.2% in the first 5 years. In contrast to previous reports, polyethylene wear is not a leading failure mechanism and rarely presents before 15 years. Implant performance is not a predominant factor of knee failure. Early failure mechanisms are primarily surgeon-dependent.
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TL;DR: In this article, the authors used the Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS) database to identify all revision total knee arthroplasty procedures performed between 2009 and 2013.
Abstract: Background Revision surgery for failed total knee arthroplasty (TKA) continues to pose a substantial burden for the United States healthcare system. The predominant etiology of TKA failure has changed over time and may vary between studies. This report aims to update the current literature on this topic by using a large national database. Specifically, we analyzed: (1) etiologies for revision TKA; (2) frequencies of revision TKA procedures; (3) various demographics including payer type and region; and (4) the length of stay (LOS) and total charges based on type of revision TKA procedure. Methods The Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS) database was used to identify all revision TKA procedures performed between 2009 and 2013. Clinical, economic, and demographic data were collected and analyzed for 337,597 procedures. Patients were stratified according to etiology of failure, age, sex, race, US census region, and primary payor class. The mean LOS and total charges were also calculated. Results Infection was the most common etiology for revision TKA (20.4%), closely followed by mechanical loosening (20.3%). The most common revision TKA procedure performed was all component revision (31.3%). Medicare was the primary payor for the greatest proportion of revisions (57.7%). The South census region performed the most revision TKAs (33.2%). The overall mean LOS was 4.5 days, with arthrotomy for removal of prosthesis without replacement procedures accounting for the longest stays (7.8 days). The mean total charge for revision TKAs was $75,028.07. Conclusion Without appropriate measures in place, the burden of revision TKAs may become overwhelming and pose a strain on providers and institutions. Continued insight into the etiology and epidemiology of revision TKAs may be the principle step towards improving outcomes and mitigating the need for future revisions.
344 citations
TL;DR: Aseptic loosening, instability, malalignment, and periprosthetic infection continue to be the primary failure mechanisms leading to revision surgery, with a substantial reduction in implant-associated revisions such as those due to polyethylene wear.
Abstract: Background: The present study was designed to clarify which underlying indications can be currently considered the main reasons for failure after total knee arthroplasty as a function of time.
Methods: We conducted a retrospective study that included all first revisions of total knee replacements during 2005 to 2010 at two high-volume arthroplasty centers. A revision was defined as the replacement of at least one prosthetic component. In the descriptive analysis, polyethylene wear, aseptic loosening, periprosthetic infection, malalignment, instability, arthrofibrosis, extensor mechanism deficiency, periprosthetic fracture, and retropatellar arthritis were given as the failure mechanism associated with an early, intermediate, or late time interval (less than one year, one to three years, and more than three years, respectively) after the index total knee arthroplasty.
Results: Three hundred and fifty-eight revision total knee arthroplasties were included. Of those revisions, 19.8% were performed within the first year after the index arthroplasty. The most common indications for revision, besides aseptic loosening (21.8%), were instability (21.8%), malalignment (20.7%), and periprosthetic infection (14.5%). Revisions due to polyethylene wear (7%) rarely occurred. In the early failure group, the primary causes of revision were periprosthetic infection (26.8%) and instability (23.9%). In the intermediate group, instability (23.3%) and malalignment (29.4%) required revision surgery, whereas late failure mechanisms were aseptic loosening (34.7%), instability (18.5%), and polyethylene wear (18.5%).
Conclusions: Aseptic loosening, instability, malalignment, and periprosthetic infection continue to be the primary failure mechanisms leading to revision surgery. Contrary to previous literature, the results in the present study showed a substantial reduction in implant-associated revisions such as those due to polyethylene wear. Failure mechanisms that occur persistently early and in the intermediate term, such as periprosthetic infection, instability, and malalignment, remain common causes of revision surgery.
Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
227 citations
TL;DR: A current concepts review on the epidemiology of failed TKAs using data from worldwide National Joint Registries is presented.
Abstract: Total knee arthroplasty (TKA) is a cost effective and extremely successful operation. As longevity increases, the demand for primary TKA will continue to rise. The success and survivorship of TKAs are dependent on the demographics of the patient, surgical technique and implant-related factors. Currently the risk of failure of a TKA requiring revision surgery ten years post-operatively is 5%. The most common indications for revision include aseptic loosening (29.8%), infection (14.8%), and pain (9.5%). Revision surgery poses considerable clinical burdens on patients and financial burdens on healthcare systems. We present a current concepts review on the epidemiology of failed TKAs using data from worldwide National Joint Registries.
225 citations
TL;DR: In this large cohort of patients with comprehensive followup of revision procedures, PJI was the dominant reason for failure during the first 15 years after primary TKA, and aseptic loosening became more important with longer followup.
Abstract: Although large series from national joint registries may accurately reflect indications for revision TKAs, they may lack the granularity to detect the true incidence and relative importance of such indications, especially periprosthetic joint infections (PJI) Using a combination of individual chart review supplemented with New Zealand Joint Registry data, we asked: (1) What is the cumulative incidence of revision TKA? (2) What are the common indications for revising a contemporary primary TKA? (3) Do revision TKA indications differ at various followup times after primary TKA? We identified 11,134 primary TKAs performed between 2000 and 2015 in three tertiary referral hospitals The New Zealand Joint Registry and individual patient chart review were used to identify 357 patients undergoing subsequent revision surgery or any reoperation for PJI All clinical records, radiographs, and laboratory results were reviewed to identify the primary revision reason The cumulative incidence of each revision reason was calculated using a competing risk estimator The cumulative incidence for revision TKA at 15 years followup was 61% (95% CI, 51%–71%) The two most-common revision reasons at 15 years followup were PJI followed by aseptic loosening The risk of revision or reoperation for PJI was 20% (95% CI, 17%–23%) and aseptic loosening was 12% (95% CI, 07%–16%) Approximately half of the revision TKAs secondary to PJI occurred within 2 years of the index TKA (95% CI, 08%–12%), whereas half of the revision TKAs secondary to aseptic loosening occurred 8 years after the index TKA (95% CI, 04%–07%) In this large cohort of patients with comprehensive followup of revision procedures, PJI was the dominant reason for failure during the first 15 years after primary TKA Aseptic loosening became more important with longer followup Efforts to improve outcome after primary TKA should focus on these areas, particularly prevention of PJI Level III, therapeutic study
193 citations
TL;DR: Surgeons should aim for optimal alignment of tibial and femoral components when performing TKA, as component malalignment can lead to increased failure rates, maltracking, and knee pain.
Abstract: Background — Surgeon-dependent factors such as optimal implant alignment are thought to play a significant role in outcome following primary total knee arthroplasty (TKA). Exact definitions and references for optimal alignment are, however, still being debated. This overview of the literature describes different definitions of component alignment following primary TKA for (1) tibiofemoral alignment in the AP plane, (2) tibial and femoral component placement in the AP plane, (3) tibial and femoral component placement in the sagittal plane, and (4) rotational alignment of tibial and femoral components and their role in outcome and implant survival.Methods — We performed a literature search for original and review articles on implant positioning following primary TKA. Definitions for coronal, sagittal, and rotational placement of femoral and tibial components were summarized and the influence of positioning on survival and functional outcome was considered.Results — Many definitions exist when evaluating pla...
186 citations
Cites background or methods from "Why Are Total Knees Failing Today? ..."
...3 distinct intraoperative methods of determining tibial component rotation have been described (Scott 2013): anatomical placement of an asymmetrical tibial tray on the cut surface, rotating the tibial tray relative to the tibial tubercle (usually using the junction of the medial and central thirds…...
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...Gap balancing technique relies on ligament balancing to establish symmetrical and rectangular flexion and also extension gap prior to definite bone resection and component placement (Scott 2013, Daines and Dennis 2014)....
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...…1995)), surgical transepicondylar axis (sTEA), anatomical transepicondylar axis (aTEA), and posterior condylar axis (PCA) and gap balancing (GB) (Scott 2013). sTEA is the line between medial femoral sulcus and the lateral femoral epicondyle, while aTEA is the line between medial and lateral…...
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References
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TL;DR: These large projected increases in demand for total hip and knee arthroplasties provide a quantitative basis for future policy decisions related to the numbers of orthopaedic surgeons needed to perform these procedures and the deployment of appropriate resources to serve this need.
Abstract: Background: Over the past decade, there has been an increase in the number of revision total hip and knee arthroplasties performed in the United States. The purpose of this study was to formulate projections for the number of primary and revision total hip and knee arthroplasties that will be performed in the United States through 2030.
Methods: The Nationwide Inpatient Sample (1990 to 2003) was used in conjunction with United States Census Bureau data to quantify primary and revision arthroplasty rates as a function of age, gender, race and/or ethnicity, and census region. Projections were performed with use of Poisson regression on historical procedure rates in combination with population projections from 2005 to 2030.
Results: By 2030, the demand for primary total hip arthroplasties is estimated to grow by 174% to 572,000. The demand for primary total knee arthroplasties is projected to grow by 673% to 3.48 million procedures. The demand for hip revision procedures is projected to double by the year 2026, while the demand for knee revisions is expected to double by 2015. Although hip revisions are currently more frequently performed than knee revisions, the demand for knee revisions is expected to surpass the demand for hip revisions after 2007. Overall, total hip and total knee revisions are projected to grow by 137% and 601%, respectively, between 2005 and 2030.
Conclusions: These large projected increases in demand for total hip and knee arthroplasties provide a quantitative basis for future policy decisions related to the numbers of orthopaedic surgeons needed to perform these procedures and the deployment of appropriate resources to serve this need.
7,032 citations
"Why Are Total Knees Failing Today? ..." refers background in this paper
...[2] The volume of revision TKA increased to more than 75,000 during the same time period and has been projected to further increase by 600% by 2030 [2]....
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TL;DR: Fifty percent of early revision total knee arthroplasties in this series were related to instability, malalignment or malposition, and failure of fixation, and half of the revisions in this group of patients were done less than 2 years after the index operation.
Abstract: The incidence of failure after knee replacement is low, yet it has been reported that more than 22,000 knee replacements are revised yearly. The purpose of the current study was to determine current mechanisms of failure of total knee arthroplasties. A retrospective review was done on all patients who had revision total knee arthroplasty during a 3-year period (September 1997-October 2000) at one institution. The preoperative evaluation in conjunction with radiographs, laboratory data, and intraoperative findings were used to determine causes of failure. Two hundred twelve surgeries were done on 203 patients (nine patients had bilateral surgeries). The reasons for failure listed in order of prevalence among the patients in this study include polyethylene wear, aseptic loosening, instability, infection, arthrofibrosis, malalignment or malposition, deficient extensor mechanism, avascular necrosis in the patella, periprosthetic fracture, and isolated patellar resurfacing. The cases reviewed included patients who had revision surgery within 9 days to 28 years (average, 3.7 years) after the previous surgery. More than half of the revisions in this group of patients were done less than 2 years after the index operation. Fifty percent of early revision total knee arthroplasties in this series were related to instability, malalignment or malposition, and failure of fixation.
1,240 citations
TL;DR: Revision TKA procedures were most commonly performed in large, urban, nonteaching hospitals in Medicare patients ages 65 to 74, and the average length of hospital stay was 5.1 days, the average total charges were $49,360, however, average LOS, average charges, and procedure frequencies varied considerably by census region, hospital type, and Procedure performed.
Abstract: Understanding the cause of failure and type of revision total knee arthroplasty (TKA) procedures performed in the United States is essential in guiding research, implant design, and clinical decision making in TKA. We assessed the causes of failure and specific types of revision TKA procedures performed in the United States using newly implemented ICD-9-CM diagnosis and procedure codes related to revision TKA data from the Nationwide Inpatient Sample (NIS) database. Clinical, demographic, and economic data were reviewed and analyzed from 60,355 revision TKA procedures performed in the United States between October 1, 2005 and December 31, 2006. The most common causes of revision TKA were infection (25.2%) and implant loosening (16.1%), and the most common type of revision TKA procedure reported was all component revision (35.2%). Revision TKA procedures were most commonly performed in large, urban, nonteaching hospitals in Medicare patients ages 65 to 74. The average length of hospital stay (LOS) for all revision TKA procedures was 5.1 days, and the average total charges were $49,360. However, average LOS, average charges, and procedure frequencies varied considerably by census region, hospital type, and procedure performed.
1,067 citations
"Why Are Total Knees Failing Today? ..." refers background or methods in this paper
...2%) were seen in an assessment of the NIS database [11]....
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...Recently implemented ICD-9CM diagnosis and procedure codes have allowed analysis of 60,000 TKA revisions using administrative claims data from the Nationwide Inpatient Sample (NIS) database [11]....
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TL;DR: Describing alignment as a dichotomous variable (aligned versus malaligned) on the basis of a mechanical axis goal of 0° ± 3° is of little practical value for predicting the durability of modern total knee arthroplasty implants.
Abstract: Background: One long-held tenet of total knee arthroplasty is that implant durability is maximized when postoperative limb alignment is corrected to 0° ± 3° relative to the mechanical axis. Recently, substantial health-care resources have been devoted to computer navigation systems that allow surgeons to more often achieve that alignment. We hypothesized that a postoperative mechanical axis of 0° ± 3° would result in better long-term survival of total knee arthroplasty implants as compared with that in a group of outliers.
Methods: Clinical and radiographic data were reviewed retrospectively to determine the fifteen-year Kaplan-Meier survival rate following 398 primary total knee arthroplasties performed with cement in 280 patients from 1985 to 1990. Preoperatively, most knees were in varus mechanical alignment (mean and standard deviation, 6° ± 8.8° of varus [range, 30° of varus to 22° of valgus]), whereas postoperatively most knees were corrected to neutral (mean and standard deviation, 0° ± 2.8° [range, 8° of varus to 9° of valgus]). Postoperatively, we defined a mechanically aligned group of 292 knees (with a mechanical axis of 0° ± 3°) and an outlier group of 106 knees (with a mechanical axis of beyond 0° ± 3°).
Results: At the time of the latest follow-up, forty-five (15.4%) of the 292 implants in the mechanically aligned group had been revised for any reason, compared with fourteen (13%) of the 106 implants in the outlier group (p = 0.88); twenty-seven (9.2%) of the 292 implants in the mechanically aligned group had been revised because of aseptic loosening, mechanical failure, wear, or patellar problems, compared with eight (7.5%) of the 106 implants in the outlier group (p = 0.88); and seventeen (5.8%) of the 292 implants in the mechanically aligned group had been revised because of aseptic loosening, mechanical failure, or wear, compared with four (3.8%) of the 106 implants in the outlier group (p = 0.49).
Conclusions: A postoperative mechanical axis of 0° ± 3° did not improve the fifteen-year implant survival rate following these 398 modern total knee arthroplasties. We believe that describing alignment as a dichotomous variable (aligned versus malaligned) on the basis of a mechanical axis goal of 0° ± 3° is of little practical value for predicting the durability of modern total knee arthroplasty implants.
Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.
696 citations
TL;DR: If all of the arthroplasties in the patients in this early failure group would have been cemented routinely and balanced carefully, the total number of early revisions would have decreased by approximately 40%, and the overall failures would have be reduced by 25%.
Abstract: Total knee arthroplasty is a predictable operation. Unfortunately, there is a subset of patients who do not do well and require revision surgery within the first 5 years. The purpose of the current study was to analyze the mechanisms of failure in patients who had revision surgery within 5 years of their index arthroplasty. Between 1986 and 1999, 440 patients with total knee arthroplasties were referred for revision surgery. An analysis of patients in whom the arthroplasties failed within 5 years of the index arthroplasty and the reasons for early failure were documented. Of the 440 patients who had revision surgery, 279 (63%) had revision surgery within 5 years of their index arthroplasty: 105 of the 279 patients with early failures (38%) had revision surgery because of infection; 74 (27%) had revision surgery because of instability; 37 (13%) had revision surgery because of failure of ingrowth of a porous-coated implant; 22 (8%) had revision surgery because of patellofemoral problems; and 21 (7%) had revision surgery because of wear or osteolysis. Only eight of the 279 patients with early failures (3%) had revision surgery because of aseptic loosening of a cemented implant. The remaining 12 patients had revision surgery because of miscellaneous problems. Host factors may prevent infection from ever being eradicated totally. The two other major patterns of failure in this series were failure of cementless fixation and instability. If all of the arthroplasties in the patients in this early failure group would have been cemented routinely and balanced carefully, the total number of early revisions would have decreased by approximately 40%, and the overall failures would have been reduced by 25%.
607 citations
"Why Are Total Knees Failing Today? ..." refers background or result in this paper
...2% of knee revisions less than two years after their index procedure, which is similar to previous reports in the literature [8,19,20]....
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...The current study attempts to report why TKA is failing today, similar to previous studies by Fehring et al and Sharkey et al who looked at failure mechanisms for revision TKA performed between 1986 and 2000 [8,9]....
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...Fehring et al reported 13% of early failures were failures of cementless fixation, pointing out that the etiologies of aseptic loosening of cementless implants will vary from cemented implants [8]....
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...They concluded that prevention of early infection requires attention to perioperative detail [8]....
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...In a series of 440 knees reported by Fehring et al and revised over a 14-year period, 63% failed less than 5 years after the index arthroplasty [8]....
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