Aims. The aim of this study was to compare ten-year longitudinal healthcare costs and revision rates for patients undergoing unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). Methods. The Humana database was used to compare 2,383 patients undergoing UKA between 2007 and 2009, who were matched 1:1 from a cohort of 63,036 patients undergoing primary TKA based on age, sex, and Elixhauser Comorbidity Index. Medical and surgical complications were tracked longitudinally for one year following surgery. Rates of revision surgery and cumulative mean healthcare costs were recorded for this period of time and compared between the cohorts. Results. Patients undergoing TKA had significantly higher rates of manipulation under anaesthesia (3.9% vs 0.9%; p < 0.001), deep vein thrombosis (5.0% vs 3.1%; p < 0.001), pulmonary embolism (1.5% vs 0.8%; p = 0.001), and renal failure (4.2% vs 2.2%; p < 0.001). Revision rates, however, were significantly higher for UKA at five years (6.0% vs 4.2%; p = 0.007) and ten years postoperatively (6.5% vs 4.4%; p = 0.002). Longitudinal-related healthcare costs for patients undergoing TKA were greater than for those undergoing UKA at one year ($24,771 vs $22,071; p < 0.001) and five years following surgery ($26,549 vs $25,730; p < 0.001); however, the mean costs of TKA were comparable to UKA at ten years ($26,877 vs $26,891; p = 0.425). Conclusion. Despite higher revision rates, patients undergoing UKA had lower mean healthcare costs than those undergoing TKA up to ten years following the procedure, at which time costs were comparable. In the era of value-based care, surgeons and policymakers should be aware of the costs involved with these procedures. UKA was associated with fewer complications at one year postoperatively but higher revision rates at five and ten years. While UKA was significantly less costly than TKA at one and five years, costs at ten years were comparable with a mean difference of only $14. Lowering the risk of revision surgery should be targeted as a source of cost savings for both UKA and TKA as the mean related healthcare costs were 2.5-fold higher in patients requiring revision surgery. Cite this article: Bone Joint J 2021;103-B(6 Supple A):23–31

Aims. Social determinants of health (SDOHs) may contribute to the total cost of care (TCOC) for patients undergoing total knee arthroplasty (TKA). The aim of this study was to investigate the association between demographic data, health status, and SDOHs on 30-day length of stay (LOS) and TCOC after this procedure. Methods. Patients who underwent TKA between 1 January 2018 and 31 December 2019 were identified. A total of 234 patients with complete SDOH data were included. Data were drawn from the Chesapeake Regional Information System, the Centers for Disease Control social vulnerability index (SVI), the US Department of Agriculture, and institutional electronic medical records. The SVI identifies areas vulnerable to catastrophic events with four themed scores: socioeconomic status; household composition and disability; minority status and language; and housing and transportation. Food deserts were defined as neighbourhoods located one or ten miles from a grocery store in urban and rural areas, respectively. Multiple regression analyses were performed to determine associations with LOS and costs after controlling for various demographic parameters. Results. Divorced status was significantly associated with an increased LOS (p = 0.043). Comorbidities significantly associated with an increased LOS included chronic obstructive pulmonary disease/asthma and congestive heart failure (p = 0.043 and p = 0.001, respectively). Communities with a higher density of tobacco stores were significantly associated with an increased LOS (p = 0.017). Comorbidities significantly associated with an increased TCOC included chronic obstructive pulmonary disease (p = 0.004), dementia (p = 0.048), and heart failure (p = 0.007). Increased TCOCs were significantly associated with patients who lived in food deserts (p = 0.001) and in areas with an increased density of tobacco stores (p = 0.023). Conclusion. Divorced marital status was significantly associated with an increased LOS following TKA. Living in food deserts and in communities with more tobacco stores were significant risk factors for increased LOS and TCOC. Food access and ease of acquiring tobacco may both prove to be prognostic of outcome after TKA and an opportunity for intervention. Cite this article: Bone Joint J 2021;103-B(6 Supple A):113–118

Revision total knee arthroplasty (TKA) is a complex procedure which carries both a greater risk for patients and greater cost for the treating hospital than does a primary TKA. As well as the increased cost of peri-operative investigations, blood transfusions, surgical instrumentation, implants and operating time, there is a well-documented increased length of stay which accounts for most of the actual costs associated with surgery. We compared revision surgery for infection with revision for other causes (pain, instability, aseptic loosening and fracture). Complete clinical, demographic and economic data were obtained for 168 consecutive revision TKAs performed at a tertiary referral centre between 2005 and 2012. Revision surgery for infection was associated with a mean length of stay more than double that of aseptic cases (21.5 vs 9.5 days, p < 0.0001). The mean cost of a revision for infection was more than three times that of an aseptic revision (£30 011 (. sd. 4514) vs £9655 (. sd. 599.7), p < 0.0001). . Current NHS tariffs do not fully reimburse the increased costs of providing a revision knee surgery service. Moreover, especially as greater costs are incurred for infected cases. These losses may adversely affect the provision of revision surgery in the NHS. Cite this article: Bone Joint J 2015;97-B:197–201

Aims. To perform an incremental cost-utility analysis and assess the impact of differential costs and case volume on the cost-effectiveness of robotic arm-assisted unicompartmental knee arthroplasty (rUKA) compared to manual (mUKA). Methods. This was a five-year follow-up study of patients who were randomized to rUKA (n = 64) or mUKA (n = 65). Patients completed the EuroQol five-dimension questionnaire (EQ-5D) preoperatively, and at three months and one, two, and five years postoperatively, which was used to calculate quality-adjusted life years (QALYs) gained. Costs for the primary and additional surgery and healthcare costs were calculated. Results. rUKA was associated with a relative 0.012 QALY gain at five years, which was associated with an incremental cost per QALY of £13,078 for a unit undertaking 400 cases per year. A cost per QALY of less than £20,000 was achieved when ≥ 300 cases were performed per year. However, on removal of the cost for a revision for presumed infection (mUKA group, n = 1) the cost per QALY was greater than £38,000, which was in part due to the increased intraoperative consumable costs associated with rUKA (£626 per patient). When the absolute cost difference (operative and revision costs) was less than £240, a cost per QALY of less than £20,000 was achieved. On removing the cost of the revision for infection, rUKA was cost-neutral when more than 900 cases per year were undertaken and when the consumable costs were zero. Conclusion. rUKA was a cost-effective intervention with an incremental cost per QALY of £13,078 at five years, however when removing the revision for presumed infection, which was arguably a random event, this was no longer the case. The absolute cost difference had to be less than £240 to be cost-effective, which could be achieved by reducing the perioperative costs of rUKA or if there were increased revision costs associated with mUKA with longer follow-up. Cite this article: Bone Jt Open 2023;4(11):889–898

Aims. The aim of this study was to estimate the incremental use of resources, costs, and quality of life outcomes associated with surgical reconstruction compared to rehabilitation for long-standing anterior cruciate ligament (ACL) injury in the NHS, and to estimate its cost-effectiveness. Methods. A total of 316 patients were recruited and randomly assigned to either surgical reconstruction or rehabilitation (physiotherapy but with subsequent reconstruction permitted if instability persisted after treatment). Healthcare resource use and health-related quality of life data (EuroQol five-dimension five-level health questionnaire) were collected in the trial at six, 12, and 18 months using self-reported questionnaires and medical records. Using intention-to-treat analysis, differences in costs, and quality-adjusted life years (QALYs) between treatment arms were estimated adjusting for baseline differences and following multiple imputation of missing data. The incremental cost-effectiveness ratio (ICER) was estimated as the difference in costs divided by the difference in QALYs between reconstruction and rehabilitation. Results. At 18 months, patients in the surgical reconstruction arm reported higher QALYs (0.052 (95% confidence interval (CI) -0.012 to 0.117); p = 0.177) and higher NHS costs (£1,017 (95% CI 557 to 1,476); p < 0.001) compared to rehabilitation. This resulted in an ICER of £19,346 per QALY with the probability of surgical reconstruction being cost-effective of 51% and 72% at a willingness-to-pay threshold of £20,000 and £30,000 per QALY, respectively. Conclusion. Surgical reconstruction as a management strategy for patients with long-standing ACL injury is more effective, but more expensive, at 18 months compared to rehabilitation management. In the UK setting, surgical reconstruction is cost-effective. Cite this article: Bone Joint J 2024;106-B(1):38–45

Aims. The aim of this study was to evaluate the cost-effectiveness of arthroscopic partial meniscectomy versus physical therapy plus optional delayed arthroscopic partial meniscectomy in young patients aged under 45 years with traumatic meniscal tears. Methods. We conducted a multicentre, open-labelled, randomized controlled trial in patients aged 18 to 45 years, with a recent onset, traumatic, MRI-verified, isolated meniscal tear without knee osteoarthritis. Patients were randomized to arthroscopic partial meniscectomy or standardized physical therapy with an optional delayed arthroscopic partial meniscectomy after three months of follow-up. We performed a cost-utility analysis on the randomization groups to compare both treatments over a 24-month follow-up period. Cost utility was calculated as incremental costs per quality-adjusted life year (QALY) gained of arthroscopic partial meniscectomy compared to physical therapy. Calculations were performed from a healthcare system perspective and a societal perspective. Results. A total of 100 patients were included: 49 were randomized to arthroscopic partial meniscectomy and 51 to physical therapy. In the physical therapy group, 21 patients (41%) received delayed arthroscopic partial meniscectomy during follow-up. Over 24 months, patients in the arthroscopic partial meniscectomy group had a mean 0.005 QALYs lower quality of life (95% confidence interval -0.13 to 0.14). The cost-utility ratio was €-160,000/QALY from the healthcare perspective and €-223,372/QALY from the societal perspective, indicating that arthroscopic partial meniscectomy incurs additional costs without any added health benefit. Conclusion. Arthroscopic partial meniscectomy is arthroscopic partial meniscectomy is unlikely to be cost-effective in treating young patients with isolated traumatic meniscal tears compared to physical therapy as a primary health intervention. Arthroscopic partial meniscectomy leads to a similar quality of life, but higher costs, compared to physical therapy plus optional delayed arthroscopic partial meniscectomy. Cite this article: Bone Joint J 2023;105-B(11):1177–1183

Aims. To assess the cost-effectiveness of a two-layer compression bandage versus a standard wool and crepe bandage following total knee arthroplasty, using patient-level data from the Knee Replacement Bandage Study (KReBS). Methods. A cost-utility analysis was undertaken alongside KReBS, a pragmatic, two-arm, open label, parallel-group, randomized controlled trial, in terms of the cost per quality-adjusted life year (QALY). Overall, 2,330 participants scheduled for total knee arthroplasty (TKA) were randomized to either a two-layer compression bandage or a standard wool and crepe bandage. Costs were estimated over a 12-month period from the UK NHS perspective, and health outcomes were reported as QALYs based on participants’ EuroQol five-dimesion five-level questionnaire responses. Multiple imputation was used to deal with missing data and sensitivity analyses included a complete case analysis and testing of costing assumptions, with a secondary analysis exploring the inclusion of productivity losses. Results. The base case analysis found participants in the compression bandage group accrued marginally fewer QALYs, on average, compared with those in the standard bandage group (reduction of 0.0050 QALYs (95% confidence interval (CI) -0.0051 to -0.0049)), and accumulated additional mean costs (incremental cost of £52.68 per participant (95% CI 50.56 to 54.80)). Findings remained robust to assumptions tested in sensitivity analyses, although considerable uncertainty surrounded the outcome estimates. Conclusion. Use of a two-layer compression bandage is marginally less effective in terms of health-related quality of life, and more expensive when compared with a standard bandage following TKA, so therefore is unlikely to provide a cost-effective option. Cite this article: Bone Jt Open 2024;5(7):550–559

Aims. To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration. Methods. We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map. Results. After screening of 5,660 articles, we included 166 studies reporting prognostic factors for outcomes after rTKA, with a median sample size of 319 patients (30 to 303,867). Overall, 50% of the studies reported prospectively collected data, and 61% of the studies were performed in a single centre. In some studies, multiple associations were reported; 180 different prognostic factors were reported in these studies. The three most frequently studied prognostic factors were reason for revision (213 times), sex (125 times), and BMI (117 times). Studies focusing on functional scores and patient-reported outcome measures as prognostic factor for the outcome after surgery were limited (n = 42). The studies reported 154 different outcomes. The most commonly reported outcomes after rTKA were: re-revision (155 times), readmission (88 times), and reinfection (85 times). Only five studies included costs as outcome. Conclusion. Outcomes and prognostic factors that are routinely registered as part of clinical practice (e.g. BMI, sex, complications) or in (inter)national registries are studied frequently. Studies on prognostic factors, such as functional and sociodemographic status, and outcomes as healthcare costs, cognitive and mental function, and psychosocial impact are scarce, while they have been shown to be important for patients with osteoarthritis. Cite this article: Bone Jt Open 2023;4(5):338–356

Aims. Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m. 2. ). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m. 2. to examine whether this is supported. Methods. This single-centre study compared 169 consecutive patients with severe obesity (BMI ≥ 40 kg/m. 2. ) (mean age 65.2 years (40 to 87); mean BMI 44.2 kg/m. 2. (40 to 66); 129/169 female) undergoing unilateral TKA to a propensity score matched (age, sex, preoperative Oxford Knee Score (OKS)) cohort with a BMI < 40 kg/m. 2. in a 1:1 ratio. Demographic data, comorbidities, and complications to one year were recorded. Preoperative and one-year patient-reported outcome measures (PROMs) were completed: EuroQol five-dimension three-level questionnaire (EQ-5D-3L), OKS, pain, and satisfaction. Using national life expectancy data with obesity correction and the 2020 NHS National Tariff, QALYs (discounted at 3.5%), and direct medical costs accrued over a patient’s lifetime, were calculated. Probabilistic sensitivity analysis (PSA) was used to model variation in cost/QALY for each cohort across 1,000 simulations. Results. All PROMs improved significantly (p < 0.05) in both groups without differences between groups. Early complications were higher in BMI ≥ 40 kg/m. 2. : 34/169 versus 52/169 (p = 0.050). A total of 16 (9.5%) patients with a BMI ≥ 40 kg/m. 2. were readmitted within one year with six reoperations (3.6%) including three (1.2%) revisions for infection. Assuming reduced life expectancy in severe obesity and revision costs, TKA in patients with a BMI ≥ 40 kg/m. 2. costs a mean of £1,013/QALY (95% confidence interval £678 to 1,409) more over a lifetime than TKA in patients with BMI < 40 kg/m. 2. In PSA replicates, the maximum cost/QALY was £3,921 in patients with a BMI < 40 kg/m. 2. and £5,275 in patients with a BMI ≥ 40 kg/m. 2. . Conclusion. Higher complication rates following TKA in severely obese patients result in a lifetime cost/QALY that is £1,013 greater than that for patients with BMI < 40 kg/m. 2. , suggesting that TKA remains a cost-effective use of healthcare resources in severely obese patients where the surgeon considers it appropriate. Cite this article: Bone Joint J 2022;104-B(4):452–463

Abstract. Introduction. Approximately 15–20% of patients report chronic pain three months after total knee replacement (TKR). The STAR care pathway is a clinically important and cost-effective personalised intervention for patients with pain 3 months after TKR. The pathway comprises screening, assesment, onward referral for treatment and follow-up over one year. In a multicentre randomised controlled trial comparing the pathway with usual care, the pathway improved pain at 6 and 12 months. This study examined the longer-term clinical and cost-effectiveness of the STAR care pathway. Methodology. STAR trial participants were followed-up at a median of 4 years post-randomisation. Co-primary outcomes were self-reported pain severity and interference in the replaced knee, assessed with the Brief Pain Inventory (BPI). Resource use from electronic hospital records was valued with UK reference costs. Results. Of the 337 participants active at trial completion, 326 had confirmed vital status, and 226 (69%) provided outcome data at a median of 4 years. The between-group difference in mean BPI severity score was −0.42 (95% CI −1.07, 0.23; p=0.20) and for BPI interference was −0.64 (95% CI −1.41, 0.12; p=0.10), favouring the intervention. Multiple imputation analyses led to attenuations of about 0.2 points. Mean hospital admission costs over four years were £2461.49 (95% CI £1354.42, £3568.57) in the intervention arm and £3791.68 (95% CI £2095.12, to £5488.24) in usual care. Conclusion. These data are consistent with sustained benefits from the STAR care pathway at 4 years, albeit attenuated and with wider confidence intervals, in part attributable to attrition after 1 year

Abstract. Introduction. Periprosthetic joint infection (PJI) is a common cause of revision total knee surgery. Although debridement and implant retention (DAIR) has lower success rates in the chronic setting, it is an accepted treatment for acute PJI. There are two broad DAIR strategies: single debridement or a planned double debridement performed days apart. The purpose of this study is to evaluate the cost-effectiveness of single versus double DAIR with antibiotic beads for acute PJI in total knee arthroplasty (TKA). Methodology. A decision tree using single or double DAIR as treatment strategies for acute PJI was constructed. Quality Adjusted Life Years (QALYs) and costs associated with the two treatment arms were calculated. Treatment success rates, failure rates, and mortality rates were derived from the literature. Medical costs were derived from both the literature and Medicare data. A cost-effectiveness plane was constructed from multiple Monte Carlo trials. A sensitivity analysis identified parameters most influencing the optimal strategy decision. Results. Double DAIR with antibiotic beads was the optimal treatment strategy both in terms of the health utility state (82% of trials), and medical cost (97% of trials). Strategy tables demonstrated that as long as the success rate of double debridement is 10% or greater than the success rate of a single debridement, the two-stage protocol is cost-effective. Conclusions. This Markov analysis demonstrates that in the setting of acute PJI following TKA, a double DAIR with antibiotic beads is more cost effective than single DAIR from a societal perspective

Aims. Blood transfusion and postoperative anaemia are complications of total knee arthroplasty (TKA) that are associated with substantial healthcare costs, morbidity, and mortality. There are few data from large datasets on the risk factors for these complications. Methods. We retrospectively reviewed the records of TKA patients from a single tertiary care institution from February 2016 to December 2020. There were a total of 14,901 patients in this cohort with a mean age of 67.9 years (SD 9.2), and 5,575 patients (37.4%) were male. Outcomes included perioperative blood transfusion and postoperative anaemia, defined a priori as haemoglobin level < 10 g/dl measured on the first day postoperatively. In order to establish a preoperative haemoglobin cutoff, we investigated a preoperative haemoglobin level that would limit transfusion likelihood to ≤ 1% (13 g/dl) and postoperative anaemia likelihood to 4.1%. Risk factors were assessed through multivariable Poisson regression modelling with robust error variance. Results. In multivariable analyses, each gram of tranexamic acid reduced transfusion likelihood by 39% (adjusted risk ratio (ARR) 0.61 (95% confidence interval (CI) 0.47 to 0.78)). Risk factors associated with an increased risk of transfusion included operating time (ARR 2.07 (95% CI 1.54 to 2.77)) and drain use (ARR 1.73 (95% CI 1.34 to 2.24)). Conclusion. In this study, we found that increased tranexamic acid dosing, decreased operating time, and decreased drain use may reduce transfusions following TKA. We also established a single preoperative haemoglobin cutoff of 13 g/dl that could help minimize transfusions and reduce postoperative complete blood counts. Cite this article: Bone Joint J 2023;105-B(10):1086–1093

Aims. The aim of this study was to analyze the true costs associated with preoperative CT scans performed for robotic-assisted total knee arthroplasty (RATKA) planning and to determine the value of a formal radiologist’s report of these studies. Methods. We reviewed 194 CT reports of 176 sequential patients who underwent primary RATKA by a single surgeon at a suburban teaching hospital. CT radiology reports were reviewed for the presence of incidental findings that might change the management of the patient. Payments for the scans, including the technical and professional components, for 330 patients at two hospitals were also recorded and compared. Results. There were 82 incidental findings in 61 CT studies, one of which led to a recommendation for additional testing. Across both institutions, the mean total payment for a preoperative scan was $446 ($8 to $3,870). The mean patient payment was $71 ($0 to $2,690). There was wide variation in payments between the institutions. In Institution A, the mean total payment was $258 ($168 to $264), with a mean patient payment of $57 ($0 to $100). The mean technical payment in this institution was $211 ($8 to $856), while the mean professional payment was $48 ($0 to $66). In Institution B, the mean total payment was $636 ($37 to $3,870), with a mean patient payment of $85 ($0 to $2,690). Conclusion. The total cost of a CT scan is low and a minimal part of the overall cost of the RATKA. No incidental findings identified on imaging led to a change in management, suggesting that the professional component could be eliminated to reduce costs. Further studies need to take into account the patient perspective and the wide variation in total costs and patient payments across institutions and insurances. Cite this article: Bone Joint J 2020;102-B(6 Supple A):79–84

Cementless knee arthroplasty has seen a recent resurgence in popularity due to conceptual advantages, including improved osseointegration providing biological fixation, increased surgical efficiency, and reduced systemic complications associated with cement impaction and wear from cement debris. Increasingly younger and higher demand patients are requiring knee arthroplasty, and as such, there is optimism cementless fixation may improve implant survivorship and functional outcomes. Compared to cemented implants, the National Joint Registry (NJR) currently reports higher revision rates in cementless total knee arthroplasty (TKA), but lower in unicompartmental knee arthroplasty (UKA). However, recent studies are beginning to show excellent outcomes with cementless implants, particularly with UKA which has shown superior performance to cemented varieties. Cementless TKA has yet to show long-term benefit, and currently performs equivalently to cemented in short- to medium-term cohort studies. However, with novel concepts including 3D-printed coatings, robotic-assisted surgery, radiostereometric analysis, and kinematic or functional knee alignment principles, it is hoped they may help improve the outcomes of cementless TKA in the long-term. In addition, though cementless implant costs remain higher due to novel implant coatings, it is speculated cost-effectiveness can be achieved through greater surgical efficiency and potential reduction in revision costs. There is paucity of level one data on long-term outcomes between fixation methods and the cost-effectiveness of modern cementless knee arthroplasty. This review explores recent literature on cementless knee arthroplasty, with regards to clinical outcomes, implant survivorship, complications, and cost-effectiveness; providing a concise update to assist clinicians on implant choice. Cite this article: Bone Jt Open 2021;2(1):48–57

Introduction. Bundled Payments (BP) were a revolutionary new experiment for CMS that tested whether risk sharing for an episode of care would improve quality and reduce costs. The initial success of BP accelerated their growth as evidence by the launch of both mandatory and commercial bundles. Success in BP is dependent on the target price and the opportunity to reduce avoidable costs during the episode of care. There is concern that the aggressive target pricing methodology in the new model (BPCI-Advanced) penalizes high performing groups that already achieved low episode costs through prior experience and investment in BP. We hypothesize that this methodology incorporates unsustainable downward trends on target prices to a point beyond reasonableness for efficient groups to reduce additional costs and will lead to a large percentage of groups opting out of BPCI-A in favor of a return to fee for service (FFS) reimbursement. Methods. Using CMS data, we compared the target price factors for hospitals that participated in both BPCI classic (2013 –2018) and BPCI Advanced (beginning 10/2018), referred to as “legacy hospitals”, with hospitals that only participated in BPCI Advanced (beginning 10/2018). With the rebasing of BPCI-A target prices in Jan 2020 and the opportunity for participants to drop out of individual episode types or the program all together, we compared the retention of episode types that hospitals initially enrolled at the onset of BPCI-A with the current enrollment in 2020. Locally, we analyzed the BPCI-A target price factors across hospitals for a large orthopaedic practice that participated in BPCI Classic and the impact it had on the financial incentive/disincentive to remain in the lower extremity joint replacement episode type in 2020. Results. At its peak in July 2015, 423 acute care hospitals participated in one or more episode type in BPCI Classic. At its peak in March 2019, 715 acute care hospitals participated in one or more episode types in BPCI-Advanced. 130 (18%) of the hospitals in BPCI Advanced were also legacy participants in BPCI Classic, enrolling in 414 of the same episode types during both programs. In 2020, 251 (61%) of the episode types that hospitals were in enrolled in for both BPCI Classic and BPCI Advanced were dropped, suggesting prior experience in BPCI influences a participant's opportunity for success in BPCI Advanced. Furthermore, an analysis of the target price factors for episode types enrolled in by legacy hospitals during both programs suggests that prior participation in BPCI Classic is correlated with more aggressive target prices. A comparison of target price factors of similar hospitals reveals that legacy BPCI Classic hospitals that participated in lower extremity joint replacement (LEJR) BPCI Advanced received a larger negative adjustment on the target price (0.11 lower on average as a product of the Peer Adjusted Trend factor and ACH Efficiency factor) than non-legacy hospitals that participated in BPCI Advanced. Furthermore, analysis of the hospital targets for a large, high-performing legacy Physician Group Practice in BPCI Classic for LEJR revealed even greater negative adjustment on the target price than non-legacy participants. Comparing participants of similar peer groups on the Peer Adjusted Trend and ACH Efficiency factors suggests that CMS expects costs to decline more for legacy hospitals that have achieved efficiency than hospitals with no prior BP experience and higher baseline spend. Conclusions. BPCI Advanced provides little to no opportunity for a reduction in cost for already efficient TJA providers, as evident by the 55% dropout rate for BPCI-A participants in LEJR between model years 1 and 3. Efficient TJA providers in BPCI Advanced are challenged by the program's utilization of a peer adjusted trend factor and efficiency factor that presumes their costs will decline at the same aggressive rate or more than nonefficient TJA providers. It remains to be seen if reverting to Medicare fee for service will support the same level of care coordination, cost and quality achieved in historical TJA bundled payment programs

Aims. The purpose of this study was to compare outcomes of combined total joint arthroplasty (TJA) (total hip arthroplasty (THA) and total knee arthroplasty (TKA) performed during the same admission) versus bilateral THA, bilateral TKA, single THA, and single TKA. Combined TJAs performed on the same day were compared with those staged within the same admission episode. Patients and Methods. Data from the National (Nationwide) Inpatient Sample recorded between 2005 and 2014 were used for this retrospective cohort study. Postoperative in-hospital complications, total costs, and discharge destination were reviewed. Logistic and linear regression were used to perform the statistical analyses. p-values less than 0.05 were considered statistically significant. Results. Combined TJA was associated with increased risk of deep vein thrombosis, prosthetic joint infection, irrigation and debridement procedures, revision arthroplasty, length of stay (LOS), and in-hospital costs compared with bilateral THA, bilateral TKA, single THA, and single TKA. Combined TJA performed on separate days of the same admission showed no statistically significant differences when compared with same-day combined TJA, but trended towards decreased total costs and total complications despite increased LOS. Conclusion. Combined TJA is associated with increased in-hospital complications, LOS, and costs. We do not recommend performing combined TJA during the same hospital stay. Cite this article: Bone Joint J 2019;101-B:573–581

Abstract. Introduction. Uni-compartmental knee replacement (UKR) has become popularised due to quicker recovery times, reduced postoperative pain, and blood loss. The desire to increase bed capacity and reduce costs, while preserving safety and patient satisfaction, has led to increased interest in day-case arthroplasty. This study observes the feasibility of UKR as a day-case procedure and whether this affects short and long-term postoperative outcomes. Methodology. Between 2018 and 2021, at a single institution and operated by a single orthopaedic surgeon, seventy-seven patients received a UKR on an elective basis. The patients were divided into two groups: ‘day-case’ for those discharged on the same day, and ‘non day-case’ group. Results. 31 patients were identified as day case procedures with the remaining 46 requiring between one to three days before discharge. Mean age, sex, modal ASA score, BMI, Charlson co-morbidity index, and pre-op oxford knee score showed no statistically significant difference between the two groups (p>0.05). No significant difference between the post-op oxford knee score at 1 year was found for patients treated and discharged as a day case procedure (37.8 +/− 6.88) and those who remained as an inpatient postoperatively (37.8 +/− 10.7); t(df) = −0.0007, p=0.994. No patients in either group suffered any complications beyond the peri-operative period. 30-day and 90-day readmission rates were equal. Conclusions. With no significant differences in post-op knee scores, complication, and readmission rates, we feel UKR can be performed as a viable day case procedure in a planned elective setting. This will result in significant cost savings

Abstract. Background. Autologous chondrocyte implantation is a NICE approved intervention however it involves the morbidity of two operations, a prolonged rehabilitation and substantial healthcare costs. This study describes a novel, one-step, bone marrow (BM) derived mesenchymal stem cell (MSC) transplantation technique for treating knee osteochondral lesions and presents our prospective clinical study investigating the success of this technique in 206 lesions over a 5 year period. Methodology. The surgical technique involves harvesting BM from patients’ anterior superior iliac spines, centrifugation to isolate MSCs and seeding into a type 1 collagen scaffold (SyngenitTM Biomatrix). Autologous fibrin glue is used to secure the scaffold into the defect. Inclusion criteria included patients aged 15 – 55 years old with symptomatic osteochondral lesions >1cm2. Exclusion criteria included patients with ligament instability, uncorrected alignment, inflammatory arthropathy and a Body Mass Index >35 kg/m2. Outcome measures included the Modified Cincinnati Knee Rating System (MCKRS), complications and reoperations. Results. Mean MCKR scores showed statistically significant improvements compared to pre-operative scores at 6 months 58.79 ± 3.5 and 1 year postoperatively 63.82 ± 3.93 with further improvements at 2 years and 5 years which did not reach statistical significance. Survival rates were 97.9%, 94% and 93.2% at 1, 2 and 5 years. Multiple regression analysis identified previous cartilage surgery, microfracture and age as factors affecting MCKRS scores (p < 0.029, 0.001 and 0.030, respectively). Conclusions. One-step BM derived stem cell transplantation demonstrates satisfactory outcomes over a 5 year period

Aims. The purpose of this study was to determine the impact of the removal of total knee arthroplasty (TKA) from the Medicare Inpatient Only (IPO) list on our Bundled Payments for Care Improvement (BPCI) Initiative in 2018. Methods. We examined our institutional database to identify all Medicare patients who underwent primary TKA from 2017 to 2018. Hospital inpatient or outpatient status was cross-referenced with Centers for Medicare & Medicaid Services (CMS) claims data. Demographics, comorbidities, and outcomes were compared between patients classified as ‘outpatient’ and ‘inpatient’ TKA. Episode-of-care BPCI costs were then compared from 2017 to 2018. Results. Of the 2,135 primary TKA patients in 2018, 908 (43%) were classified as an outpatient and were excluded from BPCI. Inpatient classified patients had longer mean length of stay (1.9 (SD 1.4) vs 1.4 (SD 1.7) days, p < 0.001) and higher rates of discharge to rehabilitation (17% vs 3%, p < 0.001). Post-acute care costs increased when comparing the BPCI patients from 2017 to 2018, ($5,037 (SD $7,792) vs $5793 (SD $8,311), p = 0.010). The removal of TKA from the IPO list turned a net savings of $53,805 in 2017 into a loss of $219,747 in 2018 for our BPCI programme. Conclusions. Following the removal of TKA from the IPO list, nearly half of the patients at our institution were inappropriately classified as an outpatient. Our target price was increased and our institution realized a substantial loss in 2018 BPCI despite strong quality metrics. CMS should address its negative implications on bundled payment programmes. Cite this article: Bone Joint J 2020;102-B(6 Supple A):19–23

Introduction. Revision total knee arthroplasty (revision TKA) occurs for a wide variety of indications and along with revision total hip arthroplasty is billed for using Diagnosis-Related Groups (DRGs) 466, 467, and 468 in the United States. However, DRGs do not account for revision etiology, a potentially substantial driver of cost. This study investigates revision TKA costs and 30-day complications by indication, employing both local granular as well as national standardized databases. Methods. Hospitalization costs and complication rates for 1,422 aseptic revision TKAs performed at a high-volume center between 2009 and 2015 were retrospectively reviewed. Additionally, charges for 28,173 revision TKAs in the National Inpatient Sample (NIS) were converted to costs using the Healthcare Cost and Utilization Project cost-to-charge ratios. 30-day complication rates for 3,450 revision TKAs were obtained using the American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP). Costs and complications were compared between revision TKAs performed for the indication of fracture, wear/loosening, and instability with use of simultaneous and pairwise comparisons and a multivariable model accounting for American Society of Anesthesiologists (ASA) score, age, and sex. Results. Local hospitalization costs for fracture (median, $30,643) were significantly higher than those for wear/loosening ($24,734; p < 0.001) or instability ($22,932; p < 0.001), with differences remaining significant even after adjusting for patient comorbidities (p < 0.001). Local fracture patients were admitted for an average of 1.9 days longer (mean length of stay [LOS]: 4.8 days; IQR: 3 – 6) than instability patients (mean LOS: 2.9; IQR: 2 – 3; p < 0.001) and 1.7 days longer than wear/loosening patients (mean LOS: 3.1, IQR: 2 – 3; p < 0.001) but had similar 30-day orthopedic-specific complication rates (10.8%) as compared to instability (11.2%; p > 0.999) and wear/loosening (15.9%; p = 0.333). Nationally, NIS costs for fracture (median, $31,207) were higher than those for other aseptic indications (wear/loosening: $21,747; instability: $16,456; p< 0.001). Combined medical and surgical complication rates for fracture (56.6% of patients with ≥1 complication) were significantly higher than those for wear/loosening (19.7%) and instability (15.5%) (p < 0.001), with 3.5 – 5.4 fold increased transfusion rates (45.7% fracture, 13.2% wear/loosening, 8.5% instability; p < 0.001) and 1.2 – 3.3 fold increased urinary tract infection rates (2.3% fracture, 0.7% wear/loosening, 1.9% instability; p = 0.004). Discussion and Conclusion. Hospitalization costs for revision TKA for fracture were 37% to 50% higher than for all other aseptic revision TKAs, both locally and nationally. This increased cost persisted even after multivariable comorbidity adjustment, the current approach for DRG assignment for both revision TKA and THA reimbursement. Indication-specific coding and reimbursement systems are necessary to maintain sustainable access to revision TKA for all patients. For figures, tables, or references, please contact authors directly