Revision total knee replacement finances: a detailed cost-analysis of operative practice at a regional tertiary referral centre.

BACKGROUND: The revision knee complexity classification (RKCC) stratifies knee revision operations depending on their level of complexity from simple revisions (R1) to highly complex cases (R3). Current financial codes used for calculation of reimbursement for knee revision services provided at the Trust, rely on patients' comorbidities. However, previous research has demonstrated that this approach may not yield an accurate financial account of knee revision arthroplasty cost. This is a single centre study from a secondary and tertiary revision unit, with work previously presented by the authors demonstrating that the majority of complex revision knee replacement within the region, take place in this unit. The aims of this study were to illustrate the current cost profile and renumeration service currently in place for revision knee and show the differences in cost based on complexity of the operation. METHODS: In this retrospective study, 90 cases who underwent revision knee operations in 2019 were analysed. Data was obtained from a tertiary referral centre where the episodes had occurred. Mean cost, tariff, and subsequent deficit were calculated for the R1, R2 and R3 episodes. RESULTS: R2 and R3 episodes were significantly more expensive than R1 episodes. The increase in cost between R3 and R2 episodes was not significant. The total cost of the revision operations was £1,162,343. Tariffs received for R2 and R3 revision operations were significantly more expensive than R1 operations. However, the increase in tariffs received for R3 operations was not significant in relation to R2 operations. The total amount of tariffs received by the Trust was £ 770,996 generating a net deficit of - £ 391,347. CONCLUSION: Current financial coding for revision knee does not accurately predict costs associated with revision knee surgery. Net deficit varies depending on the RKCC grade of the knee revision episode with more complex operations resulting in a higher mean net deficit. Implementation of the RKCC could prove to be a useful tool in generating an accurate prediction of the cost associated with knee revision surgery.

Genetic epidemiology of titin-truncating variants in the etiology of dilated cardiomyopathy.

Heart failure (HF) is a complex clinical syndrome defined by the inability of the heart to pump enough blood to meet the body's metabolic demands. Major causes of HF are cardiomyopathies (diseases of the myocardium associated with mechanical and/or electrical dysfunction), among which the most common form is dilated cardiomyopathy (DCM). DCM is defined by ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness, which leads to progressive HF. Over 60 genes are linked to the etiology of DCM. Titin (TTN) is the largest known protein in biology, spanning half the cardiac sarcomere and, as such, is a basic structural and functional unit of striated muscles. It is essential for heart development as well as mechanical and regulatory functions of the sarcomere. Next-generation sequencing (NGS) in clinical DCM cohorts implicated truncating variants in titin (TTNtv) as major disease alleles, accounting for more than 25% of familial DCM cases, but these variants have also been identified in 2-3% of the general population, where these TTNtv blur diagnostic and clinical utility. Taking into account the published TTNtv and their association to DCM, it becomes clear that TTNtv harm the heart with position-dependent occurrence, being more harmful when present in the A-band TTN, presumably with dominant negative/gain-of-function mechanisms. However, these insights are challenged by the depiction of position-independent toxicity of TTNtv acting via haploinsufficient alleles, which are sufficient to induce cardiac pathology upon stress. In the current review, we provide an overview of TTN and discuss studies investigating various TTN mutations. We also present an overview of different mechanisms postulated or experimentally validated in the pathogenicity of TTNtv. DCM-causing genes are also discussed with respect to non-truncating mutations in the etiology of DCM. One way of understanding pathogenic variants is probably to understand the context in which they may or may not affect protein-protein interactions, changes in cell signaling, and substrate specificity. In this regard, we also provide a brief overview of TTN interactions in situ. Quantitative models in the risk assessment of TTNtv are also discussed. In summary, we highlight the importance of gene-environment interactions in the etiology of DCM and further mechanistic studies used to delineate the pathways which could be targeted in the management of DCM.