Background: Over the past decade, there has been an increase in the number of revision total hip and knee arthroplasties performed in the United States. The purpose of this study was to formulate projections for the number of primary and revision total hip and knee arthroplasties that will be performed in the United States through 2030.

Methods: The Nationwide Inpatient Sample (1990 to 2003) was used in conjunction with United States Census Bureau data to quantify primary and revision arthroplasty rates as a function of age, gender, race and/or ethnicity, and census region. Projections were performed with use of Poisson regression on historical procedure rates in combination with population projections from 2005 to 2030.

Results: By 2030, the demand for primary total hip arthroplasties is estimated to grow by 174% to 572,000. The demand for primary total knee arthroplasties is projected to grow by 673% to 3.48 million procedures. The demand for hip revision procedures is projected to double by the year 2026, while the demand for knee revisions is expected to double by 2015. Although hip revisions are currently more frequently performed than knee revisions, the demand for knee revisions is expected to surpass the demand for hip revisions after 2007. Overall, total hip and total knee revisions are projected to grow by 137% and 601%, respectively, between 2005 and 2030.

Conclusions: These large projected increases in demand for total hip and knee arthroplasties provide a quantitative basis for future policy decisions related to the numbers of orthopaedic surgeons needed to perform these procedures and the deployment of appropriate resources to serve this need.

Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030.

http://xoomer.virgilio.it/lusebra/NuoviFile/PrevenzioneTVP.pdf

Prevention of venous thromboembolism

https://www.chpso.org/sites/main/files/file-attachments/chest-2008-geerts-381s-453s.pdf

Prevention of Venous Thromboembolism* American College of Chest Physicians Evidence- Based Clinical Practice Guidelines (8th Edition)

The author suggests that we apply recent research knowledge to improve our conceptualization, measures, and methodology for studying the effects of teachers’ professional development on teachers and students. She makes the case that there is a research consensus to support the use of a set of core features and a common conceptual framework in professional development impact studies. She urges us to move away from automatic biases either for or against observation, interviews, or surveys in such studies. She argues that the use of a common conceptual framework would elevate the quality of professional development studies and subsequently the general understanding of how best to shape and implement teacher learning opportunities for the maximum benefit of both teachers and students.

/pdf/improving-impact-studies-of-teachers-professional-3pzi4k3euo.pdf

Improving Impact Studies of Teachers’ Professional Development: Toward Better Conceptualizations and Measures

Prevention of Venous Thromboembolism : The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

Objective:To assess the relationship of specific patient chief physical complaints to underlying depressive symptoms in primary care practice.

The relationship of presenting physical complaints to depressive symptoms in primary care patients.

Background: When a bilateral total knee replacement is indicated, it is not clear whether it is preferable to operate on both knees during the same hospitalization (simultaneously) or to stage the procedures in two separate hospital stays. A greater risk of pulmonary embolism after simultaneous total knee replacement has been reported by some authors, but little national data are available.

Methods: We reviewed the records of 122,385 United States Medicare enrollees who had had a total knee replacement in 2000. We noted whether they had had a unilateral procedure or two procedures and, if they had had two procedures, whether both had been done during the same hospitalization or whether the operations had been performed during two separate hospital stays. Age, sex, race, residence, Medicaid eligibility (a proxy for low income), and the Charlson comorbidity score were documented for each patient as were the total numbers of total knee replacements performed in the year 2000 by the hospital and the surgeon. The probability of a symptomatic pulmonary embolism developing in the first three months after surgery was calculated for the simultaneous, staged, and unilateral procedures.

Results: Simultaneous procedures were much more likely to be performed in high-volume hospitals and by high-volume surgeons than were staged procedures. Men had proportionately more simultaneous procedures than did women. Hospitals in the northeastern United States were the most likely to perform simultaneous procedures. A pulmonary embolism developed in the first three months in 0.81% of the patients who had had a single procedure compared with 1.44% of the patients who had undergone a simultaneous procedure (adjusted hazard ratio 1.81; 95% confidence interval, 1.49, 2.20).

Conclusions: The systematic differences in patient gender, hospital and surgeon volume, and geographic region between those who undergo simultaneous total knee replacements and those who undergo staged procedures should be borne in mind when outcomes are being compared. The adjusted risk of pulmonary embolism is about 80% higher in the three months after a simultaneous procedure than in the three months after a single procedure, which suggests that the sum of the risks associated with the two operations of a staged procedure may equal or exceed the risk of simultaneous total knee replacement.

Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Bilateral total knee replacement: staging and pulmonary embolism

Background: Several studies have shown that patients who undergo total hip replacement live longer than control subjects, but the reason for this apparent protective effect is not clear. The purpose of our investigation was to assess whether the association had the characteristics of a causal relationship or whether it might appear to be due to comorbidity or other factors.

Methods: We compared survival over a six-year period for 28,469 Medicare enrollees who had elective primary total hip replacement in 1996 and a control group from the general Medicare population, matched 5:1 on year of birth, sex, race, and whether the Medicaid program paid the Medicare premium (a proxy for low income). For both the patients treated with total hip replacement and the control subjects, we used Medicare hospital claims to ascertain comorbidity, that is, whether the patient had had any of sixteen serious discharge diagnoses in the year prior to the total hip replacement (or an equivalent date for the controls). The survival patterns for the total hip arthroplasty and control cohorts were compared with use of proportional hazards regression for three follow-up periods: the first ninety days after surgery (or an equivalent date for the controls), ninety days to five years after surgery, and more than five years after surgery.

Results: The total hip replacement cohort had less comorbidity than the controls, with an approximately 30% lower prevalence for most serious diseases. Sex, age, Medicaid eligibility, and earlier serious comorbid diagnoses were important predictors of survival, but, even in analyses that adjusted for these variables, the total hip replacement cohort had better long-term survival than the controls. The patients who had a total hip replacement had a higher rate of mortality than the controls immediately after surgery, but, by three months postoperatively, the mortality rate for the patients was well below that for the controls. The overall rate of survival during the first ninety days was comparable for the two groups. From three months to five years after surgery, the mortality rate for the patients who had a total hip replacement was only two-thirds of that for the controls. After five years, the mortality rates for the two groups appeared to be converging.

Conclusions: Total hip replacement recipients survive longer than do matched controls in the Medicare population. The very rapid emergence of the lower mortality rate suggests that it is due to the selection of low-risk patients for elective surgery. However, our admittedly crude adjustment for comorbidity did not diminish the protective effect, so some effect of the procedure itself cannot be ruled out.

Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Survival following total hip replacement.

The Medicare database is commonly used for epidemiology and health services research, but validation of its data by chart review or questionnaire may be difficult and expensive. Since hospital and physician bills are independent in Medicare, however, these two data sources can be used to supplement and corroborate each other. This "internal validation" is illustrated here for hip fracture and prostatectomy. Agreement of the hospital and physician data streams regarding site of hip fracture (neck vs other), treatment of hip fracture (internal fixation vs arthroplasty), and type of prostatectomy (transurethral resection of prostate, open, or radical) was excellent, with percentage of agreement generally between 89% and 99%, and kappa statistics typically between 0.74 and 0.95. When validation with outside data sources is not readily available, such internal validation of Medicare data may be valuable.

Jane Barrett

Papers

The relationship of presenting physical complaints to depressive symptoms in primary care patients.

Bilateral total knee replacement: staging and pulmonary embolism

Survival following total hip replacement.

Internal validation of medicare claims data

Hip fracture incidence and mortality in New England