Examining Timeliness of Total Knee Replacement Among Patients with Knee Osteoarthritis in the U.S.: Results from the OAI and MOST Longitudinal Cohorts.

BACKGROUND: Patients with knee osteoarthritis may undergo total knee replacement too early or may delay or underuse this procedure. We quantified these categories of total knee replacement utilization in 2 cohorts of participants with knee osteoarthritis and investigated factors associated with each category. METHODS: Data were pooled from 2 multicenter cohort studies that collected demographic, patient-reported, radiographic, clinical examination, and total knee replacement utilization information longitudinally on 8,002 participants who had or were at risk for knee osteoarthritis and were followed for up to 8 years. Validated total knee replacement appropriateness criteria were longitudinally applied to classify participants as either potentially appropriate or likely inappropriate for total knee replacement. Participants were further classified on the basis of total knee replacement utilization into 3 categories: timely (indicating that the patient had total knee replacement within 2 years after the procedure had become potentially appropriate), potentially appropriate but knee not replaced (indicating that the knee had remained unreplaced for >2 years after the procedure had become potentially appropriate), and premature (indicating that the procedure was likely inappropriate but had been performed). Utilization rates were calculated, and factors associated with each category were identified. RESULTS: Among 8,002 participants, 3,417 knees fulfilled our inclusion and exclusion criteria and were classified into 1 of 3 utilization categories as follows: 290 knees (8% of the total and 9% of the knees for which replacement was potentially appropriate) were classified as "timely", 2,833 knees (83% of the total and 91% of those for which replacement was potentially appropriate) were classified as "potentially appropriate but not replaced", and 294 knees (comprising 9% of the total and 26% of the 1,114 total knee replacements performed) were considered to be "likely inappropriate" yet underwent total knee replacement and were classified as "premature". Of the knees that were potentially appropriate but were not replaced, 1,204 (42.5%) had severe symptoms. Compared with the patients who underwent timely total knee replacement, the likelihood of being classified as potentially appropriate but not undergoing total knee replacement was greater for black participants and the likelihood of having premature total knee replacement was lower among participants with a body mass index of >25 kg/m and those with depression. CONCLUSIONS: In 2 multicenter cohorts of patients with knee osteoarthritis, we observed substantial numbers of patients who had premature total knee replacement as well as of patients for whom total knee replacement was potentially appropriate but had not been performed >2 years after it had become potentially appropriate. Further understanding of these observations is needed, especially among the latter group. CLINICAL RELEVANCE: Undergoing total knee replacement too early may result in little or no benefit while exposing the patient to the risks of a major operation, whereas waiting too long may cause limitations in physical activity that in turn increase the risk of additional disability and chronic disease; however, little is known about timing of this surgery. We quantified the extent of premature, timely, and delayed use, and found a high prevalence of both premature and delayed use.

Cost effectiveness of patellofemoral versus total knee arthroplasty in younger patients.

AIMS: Patellofemoral arthroplasty (PFA) has experienced significant improvements in implant survivorship with second generation designs. This has renewed interest in PFA as an alternative to total knee arthroplasty (TKA) for younger active patients with isolated patellofemoral osteoarthritis (PF OA). We analysed the cost-effectiveness of PFA versus TKA for the management of isolated PF OA in the United States-based population. PATIENTS AND METHODS: We used a Markov transition state model to compare cost-effectiveness between PFA and TKA. Simulated patients were aged 60 (base case) and 50 years. Lifetime costs (2015 United States dollars), quality-adjusted life year (QALY) gains and incremental cost-effectiveness ratio (ICER) were calculated from a healthcare payer perspective. Annual rates of revision were derived from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. Deterministic and probabilistic sensitivity analysis was performed for all parameters against a $50 000/QALY willingness to pay. RESULTS: PFA was more expensive ($49 811 versus $46 632) but more effective (14.3 QALYs versus 13.3 QALYs) over a lifetime horizon. The ICER associated with the additional effectiveness of PFA was $3097. The model was mainly sensitive to utility values, with PFA remaining cost-effective when its utility exceeded that of TKA by at least 1.0%. PFA provided incremental benefits at no increased cost when annual rates of revision decreased by 24.5%. CONCLUSIONS: Recent improvements in rates of implant of survival have made PFA an economically beneficial joint-preserving procedure in younger patients, delaying TKA until implant failure or tibiofemoral OA progression. The present study quantified the minimum required marginal benefit for PFA to be cost-effective compared with TKA and identified survivorship targets for PFA to become both less expensive and more effective. These benchmarks might be used to assess clinical outcomes of PFA from an economic standpoint within the United States healthcare system. Cite this article: Bone Joint J 2017;99-B:1028-36.

The association between the timing of valve surgery and 6-month mortality in left-sided infective endocarditis.

OBJECTIVE: The optimal timing of valve surgery in left-sided infective endocarditis (IE) is undefined. We aimed to examine the association between the timing of valve surgery after IE diagnosis and 6-month mortality among patients with left-sided IE. METHODS: We analysed data from a retrospective cohort of patients with left-sided IE who underwent valve surgery within 30 days of diagnosis at a tertiary centre. The association between time from IE diagnosis to surgery and all-cause 6-month mortality was assessed using Cox proportional hazards modelling after adjusting for the propensity score (to undergo surgery 0-11 days vs >11 days, median time, after IE diagnosis). RESULTS: Of 546 left-sided IE cases seen between 1980 and 1998, 129 (23.6%) underwent valve surgery within 30 days of diagnosis. The median time between IE diagnosis and surgery was 11 days (range 1-30). There were 35/129 (27.2%) deaths in the surgical group. Using Cox proportional hazards modelling, propensity score and longer time to surgery (in days) were associated with unadjusted HRs of (1.15, 95% CI 1.04 to 1.28, per 0.10 unit change, p = 0.009) and (0.93; 95% CI 0.88 to 0.99, per day, p = 0.03), respectively. In multivariate analysis, a longer time to surgery was associated with an adjusted HR (0.97; 95% CI 0.90 to 1.03). The propensity score and time from diagnosis to surgery had a correlation coefficient of r = -0.63, making multicollinearity an issue in the multivariable model. CONCLUSION: On univariate analysis, a longer time to surgery showed a significant protective effect for the outcome of mortality. After adjusting for the propensity to undergo surgery early versus late, a longer time to surgery was no longer significant but remained in the protective direction. Multicollinearity between the time to surgery and the propensity score may have hindered our ability to detect the independent effect of time to surgery.

Determinants of radiologists' productivity in private group practices in California.

PURPOSE: The purpose of this study was to determine factors that would affect radiologists' productivity in private group practices in California. METHODS: Individual productivity data were collected for 236 private practice radiologists from 6 private radiology groups in California. The data included information on physician characteristics, facility indicators, and group practice factors that were hypothesized to affect providers' productivity. Statistical tests including chi-square testing and multivariate linear regression were used to analyze the effect of the 3 groupings of factors on the productivity of the radiologists. RESULTS: With increases in age, the number of years in practice, and the number of years in affiliation with the group practice, productivity seemed to decrease. On the other hand, productivity tended to increase if a radiologist was a shareholder, with an increase in the number of facilities served by the radiologist per day, in the proportion of imaging examinations and interventional procedures conducted, and in the proportion of those examinations stored in picture archiving and communication systems. CONCLUSIONS: To improve radiologists' productivity, group practices must invest in data-reporting infrastructure for tracking productivity, contract with outpatient imaging centers, and review group practice partnership composition and incentive models to ensure higher productivity. Future studies might consider examining the effect of other factors, such as time spent on nonclinical duties and the use of paramedical assistants in the practice.