When Medicare’s Comprehensive Care for Joint Replacement (CJR) program was implemented in 2016, the health care community—especially orthopaedic surgeons— had 2 major concerns. First, would the program actually demonstrate the ability to decrease the costs of total joint replacements while maintaining the same, or improved, outcomes? Second, would CJR promote the unintended consequence of participating hospitals and surgeons ”cherry picking” lower-risk patients and steering clear of higher-risk (and presumably higher cost) patients? Both of these questions were at the heart of the study by Barnett et al. in a recent issue of the New England Journal of Medicine.
The authors evaluated hip and knee replacements at 75 metropolitan centers that were mandated to participate in the CJR program and compared the costs, complication rates, and patient demographics to similar procedures at 121 control centers that did not participate in CJR. The authors found significantly greater decreases in institutional spending per joint-replacement episode in institutions participating in the CJR compared to those that did not. Most of these savings appeared to come from CJR-participating institutions sending fewer patients to post-acute care facilities after surgery. Furthermore, the authors did not find differences between centers participating in the CJR and control centers in terms of composite complication rate or the percentage of procedures that were performed on high-risk patients.
While this 2-year evaluation does not provide the level of detail necessary to make far-reaching conclusions, it does address two of the biggest concerns related to CJR implementation from a health-systems perspective. There may be individual CJR-participating centers that are not saving Medicare money or that are cherry picking lower-risk patients, but overall the program appears to be doing what it set out to do—successfully motivating participating hospitals and healthcare facilities to look critically at what they can do to decrease the costs of a joint-replacement episode while simultaneously maintaining a high level of patient care. The Trump administration shifted CJR to a partly voluntary model in March 2018, and I hope policymakers consider these findings if further changes to the CJR model are planned.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Concerns have arisen that the implementation of value-based, alternative payment models pegged to “bundled” episodes of care and/or patient outcomes may make it harder for a subset of patients to access the care they need. Specifically, some surgeons may be apprehensive to treat patients who have substantial medical comorbidities or socioeconomic situations that increase their risk of postsurgical complications and poor outcomes, because these alternative payment models often financially penalize physicians and hospitals for the cost of suboptimal results. The study by Shau et al. in the December 5, 2018 issue of The Journal provides data that sharpens the horns of this dilemma.
The authors used the National Readmissions Database to perform a propensity-score-matched comparison between >5,300 patients with Medicaid payer status who underwent a primary total hip arthroplasty (THA) and an equal number of patients with other types of insurance who also underwent primary THA. Shau et al. found that Medicaid-covered THA patients had significantly increased overall readmission rates (28.8% vs 21%, p <0.001, relative risk=1.37), mean length of stay (4.5 vs 3.3 days, p <0.0001), and mean total cost of care ($71,110 vs $65,309, p <0.0001), relative to the other group. These results strongly suggest that Medicaid payer status is an independent factor associated with increased resource utilization after total hip arthroplasty.
These findings can be viewed from a couple of different perspectives. First, from a preventive standpoint, surgeons and healthcare systems providing THA for Medicaid patients may need to spend more time preoperatively optimizing these patients (both physically and psychosocially) to decrease their postoperative resource burden and increase the likelihood of a good clinical outcome. Second, these results are further proof that any fair and effective alternative payment model needs to take into consideration factors such as Medicaid payer status and patient comorbidities. If they do not, such models will actually throw access barriers in front of patients in this demographic because providers may feel that caring for them increases the likelihood of being penalized financially.
Both perspectives are valid, so Medicaid payer status is a crucial factor to consider as alternative payment programs move forward. Nowadays, controlling costs is an important goal of any healthcare delivery system, but it must not lead to unintended discrimination in patient access to care. As we create further alternative payment models and refine existing ones, we must be careful not to prioritize cost cutting ahead of equitable patient access.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
The adult joint-reconstruction community has made great strides in the last 2 decades in understanding what causes aseptic loosening of arthroplasty components. For example, revelations about polyethylene particulate debris has led to the production of highly cross-linked polyethylene, which in turn has lowered wear rates, decreased revision rates, and increased the survivorship of total hip implants (see related OrthoBuzz post). Still, polyethylene debris is only one factor that can lead to aseptic loosening. Another important, yet often overlooked, factor is friction between the impacted acetabular shell and the host bone.
In the October 3, 2018 issue of The Journal, Bergmann et al. report data that help us better understand the “friction factor” in aseptic loosening. The authors implanted specially designed, instrumented acetabular components that measured in vivo friction moments among nine patients while they engaged in >1,400 different activities. The authors found that 124 of those activities led to friction moments >4 Nm—which appears to be the upper limit for facilitating a firm union between the acetabular component and the native socket.
Movements such as muscle stretching in the lunge position, the breaststroke in swimming, 2-legged standing with muscles contracted, and a single-legged stance while moving the contralateral leg were among those that created the highest friction between the implant and the host bone—and that could impede bone ingrowth into the acetabular component and thus contribute to aseptic loosening. The study also highlights the importance of periodic unloading of the prosthetic joint to allow proper synovial lubrication, which helps minimize the effects of high-friction moments. The good news is that the vast majority of activities studied do not appear to result in friction forces above the 4 Nm threshold.
Although these data should be confirmed with other in-vivo instrumented prostheses (assuming there are more patients willing to receive acetabular components capable of delivering telemetric data), they provide practical insight into the real-world forces placed on total hip prostheses after implantation. Such information can be used to counsel patients regarding high-friction and sustained-loading activities to be avoided, and it can help physical therapists and surgeons tailor postoperative regimens that optimize patient recovery while minimizing the risk to implanted prostheses.
Marc Swiontkowski, MD
Every month, JBJS publishes a Specialty Update—a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz Specialty Update summaries.
This month, Mengnai Li, MD, co-author of the September 19, 2018 Specialty Update on Hip Replacement, selected the five most clinically compelling findings from among the more than 100 studies covered in the Specialty Update.
The Benefits of HXLPE
–A double-blinded study that randomized patients to receive either a conventional polyethylene liner or one made from highly cross-linked polyethylene (HXLPE) found that, after a minimum of 10 years, the HXLPE group had significantly lower wear rates, lower prevalence of osteolysis, and lower revision rates than the conventional-liner group.
Outcomes for Hip Fracture vs OA
–A propensity score-matched cohort analysis of NSQIP data found that total hip arthroplasty (THA) undertaken to treat hip fractures among Medicare beneficiaries was significantly associated with an increased risk of CMS-reportable complications, non-homebound discharge, and readmission, relative to THA undertaken to treat osteoarthritis.1
Infection Risk Factors
–A multicenter retrospective study found that a threshold of 7.7% for hemoglobin A1c was more predictive of periprosthetic joint infection than the commonly used 7%, and the authors suggest that 7.7% should be considered the goal in preoperative patient optimization.2
THA in Patients with RA
–Recently published guidelines from the American College of Rheumatology and AAHKS regarding antirheumatic medication use in patients with rheumatic diseases who are undergoing THA suggest the following:
- Continuing nonbiologic disease-modifying antirheumatic drugs (DMARDs)
- Continuing the same daily dose of corticosteroids
- Withholding biologic agents prior to surgery
- Planning surgery for the end of the biologic dosing cycle.
All recommendations are conditional due to the low or moderate-quality evidence on which they were based.3
–A double-blinded, randomized trial found that oral tranexamic acid (TXA) provided equivalent reductions in blood loss in the setting of primary THA, at greatly reduced cost, compared with intravenous TXA.
- Qin CD, Helfrich MM, Fitz DW, Hardt KD, Beal MD, Manning DW. The Lawrence D. Dorr Surgical Techniques & Technologies Award: differences in postoperative outcomes between total hip arthroplasty for fracture vs osteoarthritis. J Arthroplasty. 2017 Sep;32(9S):S3-7. Epub 2017 Feb 6.
- Tarabichi M, Shohat N, Kheir MM, Adelani M, Brigati D, Kearns SM, Patel P, Clohisy JC, Higuera CA, Levine BR, Schwarzkopf R, Parvizi J, Jiranek WA. Determining the threshold for HbA1c as a predictor for adverse outcomes after total joint arthroplasty: a multicenter, retrospective study. J Arthroplasty. 2017 Sep;32(9S): S263-7: 267.e1. Epub 2017 May 11.
- Goodman SM, Springer B, Guyatt G, Abdel MP, Dasa V, George M, Gewurz- Singer O, Giles JT, Johnson B, Lee S, Mandl LA, Mont MA, Sculco P, Sporer S, Stryker L, Turgunbaev M, Brause B, Chen AF, Gililland J, Goodman M, Hurley-Rosenblatt A, Kirou K, Losina E, MacKenzie R, Michaud K, Mikuls T, Russell L, Sah A, Miller AS, Singh JA, Yates A. 2017 American College of Rheumatology/American Association of Hip and Knee Surgeons guideline for the perioperative management of antirheumatic medication in patients with rheumatic diseases undergoing elective total hip or total knee arthroplasty. J Arthroplasty. 2017 Sep;32(9):2628-38. Epub 2017 Jun 16.
Annual volume projections for total joint arthroplasty (TJA) have been cited frequently and applied broadly, often to estimate future costs. But with a slowdown in the growth of the annual incidence of total knee arthroplasty (TKA), updated projections are needed, and that’s what Sloan et al. provide in the September 5, 2018 issue of JBJS.
Using the National Inpatient Sample to obtain TJA incidence data, the authors first analyzed the volume of primary TJA procedures performed from 2000 to 2014. They then performed regression analyses to project future volumes of TJA procedures. Here are the numbers based on the 2000-to-2014 data:
- Primary total hip arthroplasty (THA) is projected to grow 71%, to 635,000 annual procedures by 2030.
- Primary TKA is projected to grow 85%, to 1.26 million annual procedures by 2030.
However, the TKA procedure growth rate has slowed in recent years, and models based on 2008-to-2014 data project growth to only 935,000 annual TKAs by 2030—325,000 fewer procedures relative to the 2000-to-2014 models.
Earlier studies, notably one by Kurtz et al. in 2007, obviously could not account for the reduced growth rate in TKA after 2008. A 2008 analysis by Wilson et al., based on the Kurtz et al. data, estimated that annual Medicare expenditures on TJA procedures would climb from $5 billion in 2006 to $50 billion in 2030. “Using our projections,” say Sloan et al., “we predict that Medicare expenditures on these procedures in 2030 will be less than half of that predicted by Wilson et al.”
These findings lend credence to the authors’ observation that “it is imperative that projections of orthopaedic procedures be regularly evaluated and updated to reflect current rates.”
This tip comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.
It is well-established that total hip arthroplasty (THA) improves quality of life, but how about longevity itself? Cnudde et al.1 attempted to identify associations between THA and lower mortality rates, acknowledging that such rates may also be influenced by diagnostic, patient-related, socioeconomic, and surgical factors.
Using data from the Swedish Hip Arthroplasty Register, the authors identified 131,808 patients who underwent THA between January 1, 1999 and December 31, 2012. Among those patients, 21,755 died by the end of follow-up. Relative survival among the THA patients was compared with age- and sex-matched survival data from the entire Swedish population.
Patients undergoing elective THA had a slightly improved survival rate compared with the general population for approximately 10 years after surgery, but by 12 years, there was no survival-rate difference between patients undergoing THA and the general population (r = 1.01; 95% CI, 0.99-1.02; p = 0.13).
After controlling for other relevant factors and using primary osteoarthritis as the reference diagnosis, the authors found that patients undergoing THA for osteonecrosis of the femoral head, inflammatory arthritis, and secondary osteoarthritis had poorer relative survival.
In addition, married patients and those with higher levels of education fared better. The authors could not pinpoint the reasons for the increase in relative survival among THA patients, but these findings suggest that the explanation is most likely multifactorial.
- Do Patients Live Longer After THA and Is the Relative Survival Diagnosis-specific?Cnudde P, Rolfson O, Timperley AJ, Garland A, Kärrholm J, Garellick G, Nemes S. Clin Orthop Relat Res. 2018 Feb 28. doi: 10.1007/s11999.0000000000000097. [Epub ahead of print]
Under one name or another, The Journal of Bone & Joint Surgery has published quality orthopaedic content spanning three centuries. In 1919, our publication was called the Journal of Orthopaedic Surgery, and the first volume of that journal was Volume 1 of what we know today as JBJS.
Thus, the 24 issues we turn out in 2018 will constitute our 100th volume. To help celebrate this milestone, throughout the year we will be spotlighting 100 of the most influential JBJS articles on OrthoBuzz, making the original content openly accessible for a limited time.
Unlike the scientific rigor of Journal content, the selection of this list was not entirely scientific. About half we picked from “JBJS Classics,” which were chosen previously by current and past JBJS Editors-in-Chief and Deputy Editors. We also selected JBJS articles that have been cited more than 1,000 times in other publications, according to Google Scholar search results. Finally, we considered “activity” on the Web of Science and The Journal’s websites.
We hope you enjoy and benefit from reading these groundbreaking articles from JBJS, as we mark our 100th volume. Here are two more:
Control of Bone Growth by Epiphyseal Stapling: A Preliminary Report
W P Blount and G R Clarke: JBJS, 1949 July; 31 (3): 464
This 14-page, amply illustrated article was the oldest paper selected by Kavanagh et al. in their 2013 JBJS bibliometric analysis of the 100 classic papers of pediatric orthopaedics. Blount and Clarke proved definitively that long-bone growth could be arrested by appropriately timed epiphyseal stapling and that growth would resume after staple removal. Their work spared many children with linear or angular leg deformities—often a result of polio—from the risk of more invasive operative methods.
Epidemiology of Revision Total Hip Arthroplasty in the US
K J Bozic, S M Kurtz, E Lau, K Ong, T P Vail, D J Berry: JBJS, 2009 January; 91 (1): 128
Fast forwarding 60 years from the Blount and Clarke study, we arrive at this epidemiological analysis of >51,000 revision hip replacements. The findings from this 2009 Level II prognostic study provided information that has guided THA research, implant design, and clinical decision-making throughout the past decade.
Every surgical approach to total hip arthroplasty (THA)—posterior, anterior, or lateral and conventional or minimally invasive—has adherents and critics. Despite scores of published studies comparing these different approaches, no single best practice has yet emerged.
On Monday, February 12, 2018 at 6:30 PM EST, JBJS will present a complimentary* webinar that addresses this ongoing debate with recent evidence about five different surgical approaches to THA. Moderated by James Waddell, MD, former President of the Canadian Orthopaedic Association, the webinar will springboard off two JBJS articles:
- Knut Erik Mjaaland, MD will discuss a registry study that found no significant 5-year outcome differences among four different approaches: two minimally invasive (anterior and anterolateral), and two conventional (posterior and direct lateral).
- R. Michael Meneghini, MD will explain why his group concluded that the direct anterior approach may confer a greater risk of early femoral component failure due to aseptic loosening, compared with the direct lateral or posterior approaches.
After the authors’ presentations, Anthony Unger, MD and Tad Mabry, MD will add clinical perspectives to the current state of this important research. During the last 15 minutes of the webinar, panelists will answer questions from the audience.
Space is limited, so Register Now.
* This webinar is complimentary for those who attend the event live and will continue to be available for 24 hours following its conclusion.
The relationship between chronic kidney disease (CKD) and acute kidney injury (AKI) is circular: surgical patients with preexisting CKD are at increased risk of AKI, and even mild or transient AKI is associated with future development of CKD.
In the November 1, 2017 JBJS, Gharaibeh et al. report findings from a retrospective cohort study with a nested case-control analysis that assessed the rate and risk factors associated with AKI after total hip arthroplasty (THA).
From a total of 10,323 THAs analyzed, AKI developed postoperatively in only 114 cases (1.1%). A multivariate analysis of the entire cohort identified four preoperative comorbidities that increased the risk of AKI by 2- to 4-fold: CKD, heart failure, diabetes, and hypertension. In addition to those risk factors, an analysis of the case-control cohort found that increasing BMI and perioperative blood transfusions were also associated with a higher risk of AKI.
Using data from the entire cohort, the authors developed an AKI risk calculator focused on presurgical variables (see graph). Based on that model, which will require independent validation, a 65-year-old man with either CKD or heart failure would have a 2% risk of AKI; the risk would increase to 4% if that patient had CKD and hypertension and to 16.1% in the presence of CKD, hypertension, and heart failure.
The anticipated increase in demand for joint replacements could lead to US surgeons performing approximately 572,000 THAs during the year 2030. A certain (and possibly increasing) proportion of those future procedures will occur in patients who have hypertension, diabetes, heart failure, and/or chronic kidney disease. The findings from Gharaibeh et al., especially the yet-to-be-validated AKI risk score, could help hip surgeons better counsel patients and identify those who might benefit from heightened postsurgical monitoring of kidney function.