Are Femoral Stems in Primary Total Knee Arthroplasty Cost Effective in High Fracture Risk Patients? A Risk Model and Cost Analysis.

Femoral stemmed total knee arthroplasty (FS TKA) may be used in patients deemed higher risk for periprosthetic fracture (PPF) to reduce PPF risk. However, the cost effectiveness of FS TKA has not been defined. Using a risk modeling analysis, we investigate the cost effectiveness of FS in primary TKA compared with the implant cost of revision to distal femoral replacement (DFR) following PPF. A model of risk categories was created representing patients at increasing fracture risk, ranging from 2.5 to 30%. The number needed to treat (NNT) was calculated for each risk category, which was multiplied by the increased cost of FS TKA and compared with the cost of DFR. The 50th percentile implant pricing data for primary TKA, FS TKA, and DFR were identified and used for the analysis. FS TKA resulted in an increased cost of $2,717.83, compared with the increased implant cost of DFR of $27,222.29. At 50% relative risk reduction with FS TKA, the NNT for risk categories of 2.5, 10, 20, and 30% were 80, 20, 10, and 6.67, respectively. At 20% risk, FS TKA times NNT equaled $27,178.30. A 10% absolute risk reduction in fracture risk obtained with FS TKA is needed to achieve cost neutrality with DFR. FS TKA is not cost effective for low fracture risk patients but may be cost effective for patients with fracture risk more than 20%. Further study is needed to better define the quantifiable risk reduction achieved in using FS TKA and identify high-risk PPF patients.

Direct Hospital Costs per Case of Periprosthetic Hip and Knee Joint Infections in Europe - A Systematic Review.

BACKGROUND: The rise of periprosthetic joint infections (PJIs) due to aging populations is steadily increasing the number of arthroplasties and treatment costs. This study analyzed the direct health care costs of PJI for total hip arthroplasty and total knee arthroplasty (TKA) in Europe. METHODS: The databases PubMed, Scopus, Embase, Cochrane, and Google Scholar were systematically screened for direct costs of PJI in Europe. Publications that defined the joint site and the procedure performed were further analyzed. Mean direct health care costs were calculated for debridement, antibiotics, and implant retention (DAIR), one-stage, and 2-stage revisions for hip and knee PJI, respectively. Costs were adjusted for inflation rates and reported in US-Dollar (USD). RESULTS: Of 1,374 eligible publications, 12 manuscripts were included in the final analysis after an abstract and full-text review. Mean direct costs of $32,933 were identified for all types of revision procedures for knee PJI. The mean direct treatment cost including DAIR for TKA after PJI was $19,476. For 2-stage revisions of TKA, the mean total cost was $37,980. For all types of hip PJI procedures, mean direct hospital costs were $28,904. For hip DAIR, one-stage and 2-stage treatment average costs of $7,120, $44,594, and $42,166 were identified, respectively. CONCLUSIONS: Periprosthetic joint infections are associated with substantial direct health care costs. As detailed reports on the cost of PJI are scarce and of limited quality, more detailed financial data on the cost of PJI treatment are urgently required.

All-Polyethylene Tibia: An Opportunity for Value-Based Care in Bundled Reimbursement Initiatives.

Surgeons play a critical role in making cost-effective decisions that maintain high-quality patient outcomes, which is the current focus of the Centers for Medicare & Medicaid Services. All-polyethylene tibial (APT) components often cost less during total knee arthroplasty (TKA). The authors sought to determine the relative cost savings of APT, as well as their effect on 90-day quality outcome metrics. This was a retrospective review of primary TKAs performed at a single tertiary referral center participating in the Comprehensive Care for Joint Replacement model, by 2 surgeons, from 2015 to 2017. Patient demographic data and direct hospital costs were collected, and patients were stratified by APTs vs metal-backed components. Univariable and multivariable analyses were performed for all outcome metrics. A total of 188 primary TKAs were included (92 APT, 96 metal-backed). Patients receiving APT components were older (P<.001) and had a lower body mass index (P<.001), but there was no difference in sex or American Society of Anesthesiologists score between groups. Operative time was significantly less (mean, 13 minutes) and direct surgery costs were significantly lower for APTs (P<.001). A multivariable regression model for surgical costs demonstrated significant savings (P<.001), and total hospital cost demonstrated a 6.2% average savings with APT. There was no difference in 90-day emergency department visits or re-admissions. This study demonstrates that the use of an APT is able to significantly affect not only the surgical cost but also the total hospital admission cost while maintaining equivalent 90-day outcome metrics. Strategies like this should be considered in appropriately selected patients as the incidence of TKA continues to expand. [Orthopedics. 2021;44(1):e114-e118.].

Functional outcome of total knee replacement: a study protocol for a prospective, double-blinded, parallel-group randomized, clinical controlled trial of novel, personalized and conventional implants.

BACKGROUND: The development of total knee replacement (TKR) implant designs aims to improve outcome regarding pain, function, joint stiffness, instability, patellar problems, and ultimately wear of the implant. Recently, two major orthopaedic implant manufacturers launched a new generation of TKR implants which, according to the manufacturers, provide improved functional outcome. However, the benefits of these new TKR designs claimed by the manufacturers in terms of improved functional outcome still lack scientific documentation. The present randomized controlled trial has been designed to compare three fixed bearing, cemented cruciate-retaining (CR) designs; one of the new personalized TKR design with two conventional TKR designs with the main emphasis being on functional outcome. METHODS: The present study is a prospective, double-blinded, randomized, single-center intervention trial. A total of 240 patients will be recruited to participate in a parallel-group study at Coxa Hospital for Joint Replacement, Tampere, Finland. We will compare the short-term functional outcome of TKR performed with a novel personalized TKR design (Persona CR, Zimmer, Warsaw, IN, USA) against TKRs performed with two conventional designs (PFC CR, DePuy, Warsaw, IN, USA and Nexgen CR, Zimmer, Warsaw, IN, USA). In total, 80 patients will be randomized in each of the three study arms. The primary outcome in this study is the Oxford Knee Score (OKS), which is a validated patient-reported outcome measure (PROM). Secondary outcome measures include the Forgotten Joint Score, the 15D, the UCLA activity score, and the VAS pain scale. The results will be analyzed after 2-year follow-up. DISCUSSION: This paper presents a prospective, randomized, single-center trial study protocol. It provides details of patient randomization, PROMs, follow-up, methods of analysis of the material, and publication plan. An important aspect that will be considered in the study will be the economic effects of the novel designs as they are substantially more expensive, and the benefits of the added costs remain unknown. In addition, it is especially important to carry out evaluative studies in independent centers that are not biased by the interests of the manufacturers. TRIAL REGISTRATION: Retrospectively registered, November, 2017, ClinicalTrials.gov Identifier: NCT03339557 .

Preferred Single-Vendor Program for Total Joint Arthroplasty Implants: Surgeon Adoption, Outcomes, and Cost Savings.

BACKGROUND: In total joint arthroplasty, variation in implant use can be driven by vendor relationships, surgeon preference, and technological advancements. Our institution developed a preferred single-vendor program for primary hip and knee arthroplasty. We hypothesized that this initiative would decrease implant costs without compromising performance on quality metrics. METHODS: The utilization of implants from the preferred vendor was evaluated for the first 12 months of the contract (September 1, 2017, to August 31, 2018; n = 4,246 cases) compared with the prior year (September 1, 2016, to August 31, 2017; n = 3,586 cases). Per-case implant costs were compared using means and independent-samples t tests. Performance on quality metrics, including 30-day readmission, 30-day surgical site infection (SSI), and length of stay (LOS), was compared using multivariable-adjusted regression models. RESULTS: The utilization of implants from the preferred vendor increased from 50% to 69% (p < 0.001), with greater use of knee implants than hip implants from the preferred vendor, although significant growth was seen for both (from 62% to 81% for knee, p < 0.001; and from 38% to 58% for hip, p < 0.001). Adoption of the preferred-vendor initiative was greatest among low-volume surgeons (from 22% to 87%; p < 0.001) and lowest among very high-volume surgeons (from 61% to 62%; p = 0.573). For cases in which implants from the preferred vendor were utilized, the mean cost per case decreased by 23% in the program's first year (p < 0.001), with an associated 11% decrease in the standard deviation. Among all cases, there were no significant changes with respect to 30-day readmission (p = 0.449) or SSI (p = 0.059), while mean LOS decreased in the program's first year (p < 0.001). CONCLUSIONS: The creation of a preferred single-vendor model for hip and knee arthroplasty implants led to significant cost savings and decreased cost variability within the program's first year. Higher-volume surgeons were less likely to modify their implant choice than were lower-volume surgeons. Despite the potential learning curve associated with changes in surgical implants, there was no difference in short-term quality metrics. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The cost of implanting a cemented versus cementless total knee arthroplasty.

AIMS: The aim of this study was to compare the actual cost of a cemented and cementless total knee arthroplasty (TKA) procedure. MATERIALS AND METHODS: The cost of operative time, implants, cement, and cementing accessories were included in the overall cost of the TKA procedure. Operative time was determined from a previously published study comparing cemented and cementless implants of the same design. The cost of operative time, implants, cement, and cementing accessories was determined from market and institutional data. RESULTS: Mean operative time for cemented TKA was 11.6 minutes longer for cemented TKA than cementless TKA (93.7 minutes (sd 16.7) vs 82.1 minutes (sd 16.6); p = 0.001). Using a conservative published standard of $36 per minute for operating theatre time cost, the total time cost was $418 higher for cementing TKA. The cost of cement and accessories ranged from $170 to $625. Overall, the calculated cost of cemented TKA is $588 to $1043, depending on technique. The general increased charge for cementless TKA implants over cemented TKA implants was $366. CONCLUSION: The overall procedural cost of implanting a cementless TKA is less than implanting a cemented TKA. Cost alone should not be a barrier to using cementless TKA. Cite this article: Bone Joint J 2019;101-B(7 Supple C):61-63.

All-Polyethylene versus Metal-Backed Tibial Components in Total Knee Arthroplasty.

All-polyethylene tibial (APT) implants were incorporated into the initial design of the first total knee arthroplasty (TKA) systems. Since then, a dynamic shift has taken place and metal-backed tibial (MBT) implants have become the gold standard in TKA. This has mostly been due to the theoretical advantages of intraoperative flexibility and improved biomechanics in addition to the heavy influence of device manufacturers. MBT implant comes not only with a higher cost but also with potential for complications such as osteolysis, backside wear, and thinning of the polyethylene insert, which were not previously seen with APT implant. The majority of studies comparing APT and MBT implants have shown no difference in clinical outcomes and survivorship. Newer studies from the past decade have begun highlighting the economic advantages of APT implant, especially in patients undergoing primary, uncomplicated TKA. Use of APT implants in younger patients and those with a body mass index > 35 has not been extensively studied, but the existing literature suggests the use of APT implant in these cohorts to be equally as acceptable. With modern implant design and instrumentation, rising utilization of TKA along with current and future economic strain on health care, the increased use of APT implant could result in massive savings without sacrificing positive patient outcomes.

Adoption of New Medical Technologies: The Case of Customized Individually Made Knee Implants.

OBJECTIVES: To investigate the impact of insurance coverage on the adoption of customized individually made (CIM) knee implants and to compare patient outcomes and cost effectiveness of off-the-shelf and CIM implants. METHODS: A system dynamics simulation model was developed to study adoption dynamics of CIM and meet the research objectives. The model reproduced the historical data on primary and revision knee replacement implants obtained from the literature and the Nationwide Inpatient Sample. Then the dynamics of adoption of CIM implants were simulated from 2018 to 2026. The rate of 90-day readmission, 3-year revision surgery, recovery period, time savings in operating rooms, and the associated cost within 3 years of primary knee replacement implants were used as performance metrics. RESULTS: The simulation results indicate that by 2026, an adoption rate of 90% for CIM implants can reduce the number of readmissions and revision surgeries by 62% and 39%, respectively, and can save hospitals and surgeons 6% on procedure time and cut down cumulative healthcare costs by approximately $38 billion. CONCLUSIONS: CIM implants have the potential to deliver high-quality care while decreasing overall healthcare costs, but their adoption requires the expansion of current insurance coverage. This work presents the first systematic study to understand the dynamics of adoption of CIM knee implants and instrumentation. More broadly, the current modeling approach and systems thinking perspective could be used to consider the adoption of any emerging customized therapies for personalized medicine.

Do More Expensive Total Knee Arthroplasty Prostheses Provide Greater Improvements in Outcomes Over Less Expensive Prostheses Sold by a Physician-owned Distributorship?

BACKGROUND: It is unknown whether more expensive total knee prostheses provide better improvements in patient-determined outcomes compared with less expensive prostheses. A physician-owned distributorship (POD) was created with a goal to provide lower cost implants to hospitals as an alternative to higher cost prostheses sold by the large orthopaedic implant companies. The hypothesis was that lower cost total knee prostheses would have equivalent outcomes, while resulting in lower costs to the hospitals purchasing them compared with higher cost industry-supplied knee prostheses. METHODS: From May 2013 until January 2015, a POD existed which included five surgeons that performed total knee arthroplasties and were willing to follow the outcomes to ensure quality. The POD sold two knee arthroplasty systems at a cost that was lower than that of the large industry companies. Surgeons were allowed to use either POD knees or industry knees at their own discretion. Patients were followed up prospectively to determine The Knee Injury and Osteoarthritis Outcome Score (KOOS) outcomes at 2 years and any incidence of knee complications that required surgery. RESULTS: Two hundred-nine knees (35.2%) had a POD knee implanted, and 385 knees had an industry knee implanted. Both POD knees and industry knees showed statistically significant improvements (P < 0.0001) for all subgroups of the KOOS. No statistically significant difference was observed in improvement in any subgroup of the KOOS between the groups. Knee complications requiring surgical intervention were similar (2.9% POD knees versus 3.6% industry knees; P = 0.58). Using lower cost POD knees saved $209,875.71. CONCLUSIONS: No difference was observed in improvements in outcomes or complications in the lower cost POD-supplied knees compared with the higher cost industry-supplied knees. Hospitals and surgeons may consider using lower cost prostheses because the increased cost of the prosthesis has not been correlated to improved outcomes. LEVEL OF EVIDENCE: Level II therapeutic prospective cohort study.

Economic benefits of microprocessor controlled prosthetic knees: a modeling study.

BACKGROUND: Advanced prosthetic knees allow for more dynamic movements and improved quality of life, but payers have recently started questioning their value. To answer this question, the differential clinical outcomes and cost of microprocessor-controlled knees (MPK) compared to non-microprocessor controlled knees (NMPK) were assessed. METHODS: We conducted a literature review of the clinical and economic impacts of prosthetic knees, convened technical expert panel meetings, and implemented a simulation model over a 10-year time period for unilateral transfemoral Medicare amputees with a Medicare Functional Classification Level of 3 and 4 using estimates from the published literature and expert input. The results are summarized as an incremental cost effectiveness ratio (ICER) from a societal perspective, i.e., the incremental cost of MPK compared to NMPK for each quality-adjusted life-year gained. All costs were adjusted to 2016 U.S. dollars and discounted using a 3% rate to the present time. RESULTS: The results demonstrated that compared to NMPK over a 10-year time period: for every 100 persons, MPK results in 82 fewer major injurious falls, 62 fewer minor injurious falls, 16 fewer incidences of osteoarthritis, and 11 lives saved; on a per person per year basis, MPK reduces direct healthcare cost by $3676 and indirect cost by $909, but increases device acquisition and repair cost by $6287 and total cost by $1702; on a per person basis, MPK is associated with an incremental total cost of $10,604 and increases the number of life years by 0.11 and quality adjusted life years by 0.91. MPK has an ICER ratio of $11,606 per quality adjusted life year, and the economic benefits of MPK are robust in various sensitivity analyses. CONCLUSIONS: Advanced prosthetics for transfemoral amputees, specifically MPKs, are associated with improved clinical benefits compared to non-MPKs. The economic benefits of MPKs are similar to or even greater than those of other medical technologies currently reimbursed by U.S. payers.

When Would a Metal-Backed Component Become Cost-Effective Over an All-Polyethylene Tibia in Total Knee Arthroplasty?

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention. Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe. Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates. Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Polyethylene on Cement Spacers: An Economic Approach to an Effective Infection Eradication in a Two-Stage Knee Revision Articulating Spacers.

Although two-stage revision surgery is generally considered as the gold standard treatment for periprosthetic joint infection (PJI) after total knee arthroplasty, the procedure is limited by the costs of commercially preformed spacers used for treatment. In this work, we aim to report a modified approach by which the cost of the spacer could be significantly reduced without compromising eradication of infection. Between 2010 and 2016, we performed a total of 11 two-stage revision arthroplasties using a surgically handmade spacer with a new polyethylene insert. Patients were aged 59 to 80 years old (mean 69.9 years), with a range of motion (ROM) between 20° and 65° on the affected knee (mean 46.4°) before the first-stage revision surgery. During the perioperative and postoperative period, functional and clinical evaluation of the patients were performed, including the determination of their articular ROM, Knee Society Knee Scores (KSKS), and Knee Society Function Scores (KSFS). All patients were followed up for an average of 2 years, ranging from 1 to 4 years. After the second-stage revision surgery, the mean ROM was increased by 46.8° (46.4°-93.2°) after the second-stage revision. KSKS and KSFS scores were recorded to increase by an average of 44.5° (range 40.4°-84.9°) and 46.9° (range 38.5°-85.4°), respectively. All 11 patients underwent a successful two-stage revision surgery, and no evidence of postsurgical infection was found during patient follow-up examination. Our results show that this personalized handmade antibiotic-loaded articulating spacer is cost-effective and efficacious.

Cost Analysis of All-Polyethylene Compared to Metal-Backed Implants in Total Knee Arthroplasty.

INTRODUCTION: The growing trends of total knee arthroplasty (TKA) foreshadow an inevitable increase in the financial burden on healthcare expenditure estimated to almost nine billion dollars annually. This study aims to demonstrate the potential savings when using all-polyethylene (AP) compared to metal-backed (MB) tibial components and describes the cost variability amongst three major commercially available implants. MATERIALS AND METHODS: The cost of AP versus MB implants was analyzed using a large nationwide database, Emergency Care Research Institute (ECRI). Cost of femoral components and patellar buttons were excluded. The three manufacturers included in the study were DePuy, Smith&Nephew, and Stryker (Zimmer data was not available for analysis). RESULTS: Our results show that AP components were significantly less costly in comparison to other manufacturers, and the average AP price was $1,009. The average MB (baseplate plus liner) price was $2,054 (p<0.01). Analysis of variance (ANOVA) of the means of the AP components showed no significant difference in prices among the three studied manufacturers (p=0.946). DISCUSSION: Our results demonstrate that, regardless of the manufacturing company, AP tibial components are significantly cheaper than their MB counterparts. A literature review revealed that, when indicated, AP implants are not inferior to MB in terms of survivorship or outcome. The average savings was more than $1,000 per TKA when multiplied even by a small portion of the large volume of TKAs completed annually. This can translate into millions of dollars in savings in healthcare expenditures. With the impending legislation of the bundled-payment initiative, orthopaedic surgeons should be aware of less costly implant options that can positively impact outcomes and/or quality of care.

Comparative Analysis of Hospital Length of Stay and Discharge Status of Two Contemporary Primary Total Knee Systems.

This study compares the differences in hospital length of stay (LOS), operating room time (ORT), discharge status, and total hospital costs among primary total knee arthroplasty (TKA) patients implanted with one of two contemporary primary total knee systems. A retrospective cohort analysis of elective inpatient, primary, unilateral TKA patients in the United States from 2013 to 2014 was conducted using the Premier Perspective® hospital billing database. The included patients had a diagnosis for osteoarthritis and received an ATTUNE® Knee (Gradually Reducing Radius Knee) or Triathlon™ (Single Radius Knee) from a hospital where both devices were used. Patient, provider, and procedure characteristics were included in generalized estimating equation (GEE) models to explore the impact of device on LOS, ORT, discharge status, and costs accounting for clustering within hospitals. A 1:1 propensity score-matched sensitivity analysis was also conducted. There were 1,178 patients who received gradually reducing radius knee and 5,707 patients who received single radius knee. GEE models indicated that the adjusted mean LOS and ORT for patients who received gradually reducing radius knee were significantly shorter than those who received single radius knee (p < 0.001). The adjusted odds ratios for gradually reducing radius knee patients being discharged to a skilled nursing facility (SNF) or other facility were 39% lower than that for single radius knee patients (odds ratio = 0.61; 95% confidence interval: 0.50-0.75; p < 0.001). The adjusted mean costs for gradually reducing radius knee patients were significantly lower than the single radius knee patients ($12,824 [1,813] vs. $18,713 [1,505]; p < 0.01). Findings were similar in the propensity-matched cohort of 2,044 patients, which was balanced on baseline covariates between devices (standardized differences were ≤ 8%). Patients who received gradually reducing radius knee had a shorter LOS and ORT, were less likely to be discharged to a SNF or other facility, and had lower total hospital cost than those who received single radius knee. These outcomes are increasingly relevant as hospitals bear the financial burden for episodes of care, and will require optimization to achieve success under the Centers for Medicare and Medicaid Services' Comprehensive Care for Joint Replacement model.

Risk Adjustment Is Necessary in Value-based Outcomes Models for Infected TKA.

BACKGROUND: The Medicare Access and CHIP Reauthorization Act of 2015 provides the framework to link reimbursement for providers based on outcome metrics. Concerns exist that the lack of risk adjustment for patients undergoing revision TKA for an infection may cause problems with access to care. QUESTIONS/PURPOSES: (1) After controlling for confounding variables, do patients undergoing revision TKA for infection have higher 30-day readmission, reoperation, and mortality rates than those undergoing revision TKA for aseptic causes? (2) Compared with patients undergoing revision TKA who are believed not to have infections, are patients undergoing revision for infected TKAs at increased risk for complications? METHODS: We queried the American College of Surgeons National Surgical Quality Improvement Program database for patients undergoing revision TKA from 2012 to 2015 identified by Current Procedural Terminology (CPT) codes 27486, 27487, and 27488. Of the 10,848 patients identified, four were excluded with a diagnosis of malignancy (International Classification of Diseases, 9th Revision code 170.7, 170.9, 171.8, or 198.5). This validated, national database records short-term outcome data for inpatient procedures and does not rely on administrative coding data. Demographic variables, comorbidities, and outcomes were compared between patients believed to have infected TKAs and those undergoing revision for aseptic causes. A multivariate logistic regression analysis was performed to identify independent factors associated with complications, readmissions, reoperations, and mortality. RESULTS: After controlling for demographic factors and medical comorbidities, TKA revision for infection was independently associated with complications (odds ratio [OR], 3.736; 95% confidence interval [CI], 3.198-4.365; p < 0.001), 30-day readmission (OR, 1.455; 95% CI, 1.207-1.755; p < 0.001), 30-day reoperation (OR, 1.614; 95% CI, 1.278-2.037; p < 0.001), and 30-day mortality (OR, 3.337; 95% CI, 1.213-9.180; p = 0.020). Patients with infected TKA had higher rates of postoperative infection (OR, 3.818; 95% CI, 3.082-4.728; p < 0.001), renal failure (OR, 36.709; 95% CI, 8.255-163.231; p < 0.001), sepsis (OR, 7.582; 95% CI, 5.529-10.397; p < 0.001), and septic shock (OR, 3.031; 95% CI, 1.376-6.675; p = 0.006). CONCLUSIONS: Policymakers should be aware of the higher rate of mortality, readmissions, reoperations, and complications in patients with infected TKA. Without appropriate risk adjustment or excluding these patients all together from alternative payment and quality reporting models, fewer providers will be incentivized to care for patients with infected TKA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Success rates, characteristics, and costs of articulating antibiotic spacers for total knee periprosthetic joint infection.

BACKGROUND: The optimal type, characteristics, and success rates of articulating antibiotic spacers used during total knee arthroplasty (TKA) periprosthetic joint infection (PJI) have not been well defined in a single series. We sought to (1) determine the success rate for three unique spacer constructs and (2) evaluate any microbiological, surgical, or patient characteristics that would influence the success rate. METHODS: We retrospectively reviewed patients who underwent a two-stage exchange for a TKA PJI with a prefabricated spacer (PREFAB), home-made mold (MOLD), or autoclaved femoral component (AUTOCL). Patient demographics, microbiology data, amount of antibiotic in each spacer construct, postoperative course, and infection cure outcomes were evaluated. RESULTS: The success rate for being infection free at final follow-up without the need for further reoperation for infection was 82.7% in the PREFAB group, 88.4% in the MOLD group, and 79.4% in the AUTOCL group (p=0.54). There was no clear statistical link between raw quantities of vancomycin and aminoglycoside in the spacer and a successful outcome. The surgeon's own intraoperatively created mold group had the lowest construct cost at a mean $1341.00±889.10 (p<0.0001) per construct, while the commercial cement molds had the highest mean cost at $5439.00±657.80 (p<0.0001). CONCLUSIONS: There was no statistically significant difference in the success rates between the antibiotic spacer types. The surgeon's own intraoperative mold had the least overall associated cost.

Técnica de recuperación acelerada (fast-track) aplicada a cirugía protésica primaria de rodilla y cadera. Análisis de costos y complicaciones / Fast-track recovery technique applied to primary total hip and knee replacement surgery. Analysis of costs and complications

Objetivo. Determinar el ahorro económico que supone la implantación de un sistema de recuperación rápida (fast-track) al compararlo con el método de recuperación convencional en artroplastia primaria de cadera (ATC) y rodilla (ATR). Asimismo, determinar si existen diferencias entre ambos en el índice de complicaciones. Material y métodos. Estudio retrospectivo descriptivo, incluyendo 100 artroplastias primarias utilizando el método fast-track y 100 utilizando recuperación convencional. Las variables comparadas entre ambos grupos fueron edad, sexo, índice de comorbilidad de Charlson, ASA, estancia media, complicaciones intrahospitalarias y durante los primeros seis meses e índice de reingresos y transfusiones. Se determinó el coste global para cada procedimiento y por día de ingreso, y el ahorro se calculó según la reducción de la estancia media. Resultados. Ambos grupos fueron comparables en cuanto a edad, sexo, ASA e índice de Charlson. La reducción de la estancia media hospitalaria fue de 4,5 días para el grupo de ATR y 2,1 días para el de ATC. El ahorro calculado fue de 1.266 euros para el grupo de ATR y de 583 euros en el de ATC. No se observaron diferencias significativas en cuanto a complicaciones intrahospitalarias, necesidad de transfusiones, reingresos y complicaciones durante los primeros 6 meses. Discusión. Existen pocos trabajos de análisis de costos en relación con la implantación de sistemas de recuperación rápida en cirugía protésica. Diversas series publicadas tampoco observaron un mayor índice de complicaciones utilizando este método. La utilización del método fast-track representó un ahorro de 1.266 euros para el grupo de ATR y de 583 euros para el grupo de ATC sin aparente repercusión sobre el índice de complicaciones (AU)

Purpose. To determine the cost reduction and complication rates of using an enhanced recovery pathway (Fast-track) when compared to traditional recovery in primary total hip replacement (THR) and total knee replacement (TKR), as well as to determine if there were significant differences in complication rates. Material and methods. Retrospective review of 100 primary total arthroplasties using the Fast-track recovery system and another 100 using conventional recovery. Gender, Charlston comorbidity index, ASA score, length of stay and early complications were measured, as well in-hospital complications and those in the first six months, re-admissions and transfusion rates. The total and daily cost of stay was determined and the cost reduction was calculated based on the reduction in the length of stay found between the groups. Results. Both groups where comparable as regards age, gender, ASA score, and Charlston index. The mean reduction in length of stay was 4.5 days for TKR and 2.1 days for THR. The calculated cost reduction was 1266 euros for TKR and 583 euros for THR. There were no statistically significant differences between groups regarding in-hospital complications, transfusion requirements, re-admissions and complication rates in the first six months. Discussion. There are few publications in the literature reviewed that analyse the cost implications of using fast-track recovery protocols in arthroplasty. Several published series comparing recovery protocols found no significant differences in complication rates either. The use of a fast-track recovery protocol resulted in a significant cost reduction of 1266 euros for the TKR group and 583 for the THR group, without affecting complication rates (AU)

Stratified cost-utility analysis of C-Leg versus mechanical knees: Findings from an Italian sample of transfemoral amputees.

BACKGROUND: The fitting rate of the C-Leg electronic knee (Otto-Bock, D) has increased steadily over the last 15 years. Current cost-utility studies, however, have not considered the patients' characteristics. OBJECTIVES: To complete a cost-utility analysis involving C-Leg and mechanical knee users; "age at the time of enrollment," "age at the time of first prosthesis," and "experience with the current type of prosthesis" are assumed as non-nested stratification parameters. STUDY DESIGN: Cohort retrospective. METHODS: In all, 70 C-Leg and 57 mechanical knee users were selected. For each stratification criteria, we evaluated the cost-utility of C-Leg versus mechanical knees by computing the incremental cost-utility ratio, that is, the ratio of the "difference in cost" and the "difference in utility" of the two technologies. Cost consisted of acquisition, maintenance, transportation, and lodging expenses. Utility was measured in terms of quality-adjusted life years, computed on the basis of participants' answers to the EQ-5D questionnaire. RESULTS: Patients over 40 years at the time of first prosthesis were the only group featuring an incremental cost-utility ratio (88,779 €/quality-adjusted life year) above the National Institute for Health and Care Excellence practical cost-utility threshold (54,120 €/quality-adjusted live year): C-Leg users experience a significant improvement of "mobility," but limited outcomes on "usual activities," "self-care," "depression/anxiety," and reduction of "pain/discomfort." CONCLUSION: The stratified cost-utility results have relevant clinical implications and provide useful information for practitioners in tailoring interventions. Clinical relevance A cost-utility analysis that considered patients characteristics provided insights on the "affordability" of C-Leg compared to mechanical knees. In particular, results suggest that C-Leg has a significant impact on "mobility" for first-time prosthetic users over 40 years, but implementation of specific low-cost physical/psychosocial interventions is required to retun within cost-utility thresholds.

Residual standard deviation: Validation of a new measure of dual-task cost in below-knee prosthesis users.

We developed and evaluated properties of a new measure of variability in stride length and cadence, termed residual standard deviation (RSD). To calculate RSD, stride length and cadence are regressed against velocity to derive the best fit line from which the variability (SD) of the distance between the actual and predicted data points is calculated. We examined construct, concurrent, and discriminative validity of RSD using dual-task paradigm in 14 below-knee prosthesis users and 13 age- and education-matched controls. Subjects walked first over an electronic walkway while performing separately a serial subtraction and backwards spelling task, and then at self-selected slow, normal, and fast speeds used to derive the best fit line for stride length and cadence against velocity. Construct validity was demonstrated by significantly greater increase in RSD during dual-task gait in prosthesis users than controls (group-by-condition interaction, stride length p=0.0006, cadence p=0.009). Concurrent validity was established against coefficient of variation (CV) by moderate-to-high correlations (r=0.50-0.87) between dual-task cost RSD and dual-task cost CV for both stride length and cadence in prosthesis users and controls. Discriminative validity was documented by the ability of dual-task cost calculated from RSD to effectively differentiate prosthesis users from controls (area under the receiver operating characteristic curve, stride length 0.863, p=0.001, cadence 0.808, p=0.007), which was better than the ability of dual-task cost CV (0.692, 0.648, respectively, not significant). These results validate RSD as a new measure of variability in below-knee prosthesis users. Future studies should include larger cohorts and other populations to ascertain its generalizability.