Sunny H. Kim

Increasing Incidence of Shoulder Arthroplasty in the United States

BACKGROUND The number of total shoulder arthroplasties performed in the United States increased slightly between 1990 and 2000. However, the incidence of shoulder arthroplasty in recent years has not been well described. The purpose of the present study was to examine recent trends in shoulder hemiarthroplasty and total shoulder arthroplasty along with the common reasons for these surgical procedures in the United States. METHODS We modeled the incidence of shoulder arthroplasty from 1993 to 2008 with use of the Nationwide Inpatient Sample. On the basis of hemiarthroplasty and total shoulder arthroplasty cases that were identified with use of surgical procedure codes, we conducted a design-based analysis to calculate national estimates. RESULTS While the annual number of hemiarthroplasties grew steadily, the number of total shoulder arthroplasties showed a discontinuous jump (p < 0.01) in 2004 and increased with a steeper linear slope (p < 0.01) since then. As a result, more total shoulder arthroplasties than hemiarthroplasties have been performed annually since 2006. Approximately 27,000 total shoulder arthroplasties and 20,000 hemiarthroplasties were performed in 2008. More than two-thirds of total shoulder arthroplasties were performed in adults with an age of sixty-five years or more. Osteoarthritis was the primary diagnosis for 43% of hemiarthroplasties and 77% of total shoulder arthroplasties in 2008, with fracture of the humerus as the next most common primary diagnosis leading to hemiarthroplasty. CONCLUSIONS The number of shoulder arthroplasties, particularly total shoulder arthroplasties, is growing faster than ever. The use of reverse total arthroplasty, which was approved by the United States Food and Drug Administration in November 2003, may be part of the reason for the greater increase in the number of total shoulder arthroplasties. A long-term follow-up study is warranted to evaluate total shoulder arthroplasty in terms of patient outcomes, safety, and implant longevity.

Increase in outpatient knee arthroscopy in the United States: a comparison of National Surveys of Ambulatory Surgery, 1996 and 2006.

BACKGROUND This study was proposed to investigate the changes in the utilization of knee arthroscopy in an ambulatory setting over the past decade in the United States as well as its implications. METHODS The National Survey of Ambulatory Surgery, last carried out in 1996, was conducted again in 2006 by the Centers for Disease Control and Prevention. We analyzed the cases with procedure coding indicative of knee arthroscopy or anterior cruciate ligament reconstruction. To produce estimates for all arthroscopic procedures on the knee in an ambulatory setting in the United States for each year, we performed a design-based statistical analysis. RESULTS The number of arthroscopic procedures on the knee increased 49% between 1996 and 2006. While the number of arthroscopic procedures for knee injury had dramatically increased, arthroscopic procedures for knee osteoarthritis had decreased. In 1996, knee arthroscopies performed in freestanding ambulatory surgery centers comprised only 15% of all orthopaedic procedures, but the proportion increased to 51% in 2006. There was a large increase in knee arthroscopy among middle-aged patients regardless of sex. In 2006, >99% of arthroscopic procedures on the knee were in an outpatient setting. Approximately 984,607 arthroscopic procedures on the knee (95% confidence interval, 895,999 to 1,073,215) were performed in an outpatient setting in 2006. Among those, 127,446 procedures (95% confidence interval, 95,124 to 159,768) were for anterior cruciate ligament reconstruction. Nearly 500,000 arthroscopic procedures were performed for medial or lateral meniscal tears. CONCLUSIONS This study revealed that the knee arthroscopy rate in the United States was more than twofold higher than in England or Ontario, Canada, in 2006. Our study found that nearly half of the knee arthroscopic procedures were performed for meniscal tears. Meniscal damage, detected by magnetic resonance imaging, is commonly assumed to be the source of pain and symptoms. Further study is imperative to better define the symptoms, physical findings, and radiographic findings that are predictive of successful arthroscopic treatment.

Epidemiology of humerus fractures in the United States: nationwide emergency department sample, 2008

To evaluate the occurrence of emergency department (ED) visits due to humerus fractures in the US.

Younger Age Is Associated with a Higher Risk of Early Periprosthetic Joint Infection and Aseptic Mechanical Failure After Total Knee Arthroplasty

BACKGROUND Although early aseptic mechanical failure after total knee arthroplasty has been reported in younger patients, it is unknown whether early revision due to periprosthetic joint infection is more or less frequent in this patient subgroup. The purpose of this study was to determine whether the incidence of early periprosthetic joint infection requiring revision knee surgery is significantly different in patients younger than fifty years of age compared with older patients following primary unilateral total knee arthroplasty. METHODS A large population-based study was conducted with use of the California Patient Discharge Database, which allows serial linkage of all discharge data from nonfederal hospitals in the state over time. Patients undergoing primary unilateral total knee arthroplasty during 2005 to 2009 were identified. Principal outcomes were partial or complete revision arthroplasty due to periprosthetic joint infection or due to aseptic mechanical failure within one year. Multivariate analysis included risk adjustment for important demographic and clinical variables. The effect of hospital total knee arthroplasty volume on the outcomes of infection and mechanical failure was analyzed with use of hierarchical modeling. RESULTS At one year, 983 (0.82%) of 120,538 primary total knee arthroplasties had undergone revision due to periprosthetic joint infection and 1385 (1.15%) had undergone revision due to aseptic mechanical failure. The cumulative incidence in patients younger than fifty years of age was 1.36% for revision due to periprosthetic joint infection and 3.49% for revision due to aseptic mechanical failure. In risk-adjusted models, the risk of periprosthetic joint infection was 1.8 times higher in patients younger than fifty years of age (odds ratio = 1.81, 95% confidence interval = 1.33 to 2.47) compared with patients sixty-five years of age or older, and the risk of aseptic mechanical failure was 4.7 times higher (odds ratio = 4.66, 95% confidence interval = 3.77 to 5.76). The rate of revision due to infection at hospitals in which a mean of more than 200 total knee arthroplasties were performed per year was lower than the expected (mean) value (p = 0.04). CONCLUSIONS Patients younger than fifty years of age had a significantly higher risk of undergoing revision due to periprosthetic joint infection or to aseptic mechanical failure at one year after primary total knee arthroplasty.

A Population-Based Comparison of the Incidence of Adverse Outcomes After Simultaneous-Bilateral and Staged-Bilateral Total Knee Arthroplasty

BACKGROUND It is unclear whether simultaneous-bilateral total knee arthroplasty is as safe as staged-bilateral arthroplasty is. We are aware of no randomized trials comparing the safety of these surgical strategies. The purpose of this study was to retrospectively compare these two strategies, with use of an intention-to-treat approach for the staged-bilateral arthroplasty cohort. METHODS We used linked hospital discharge data to compare the safety of simultaneous-bilateral and staged-bilateral knee arthroplasty procedures performed in California between 1997 and 2007. Estimates were generated to take into account patients who had planned to undergo staged-bilateral arthroplasty but never underwent the second procedure because of death, a major complication, or elective withdrawal. Hierarchical logistic regression modeling was used to adjust the comparisons for patient and hospital characteristics. The principal outcomes of interest were death, a major complication involving the cardiovascular system, and a periprosthetic knee infection or mechanical malfunction requiring revision surgery. RESULTS Records were available for 11,445 simultaneous-bilateral arthroplasty procedures and 23,715 staged-bilateral procedures. On the basis of an intermediate estimate of the number of complications that occurred after the first procedure in a staged-bilateral arthroplasty, patients who underwent simultaneous-bilateral arthroplasty had a significantly higher adjusted odds ratio (OR) of myocardial infarction (OR = 1.6, 95% confidence interval [CI] = 1.2 to 2.2) and of pulmonary embolism (OR = 1.4, 95% CI = 1.1 to 1.8), similar odds of death (OR = 1.3, 95% CI = 0.9 to 1.9) and of ischemic stroke (OR = 1.0, 95% CI = 0.6 to 1.6), and significantly lower odds of major joint infection (OR = 0.6, 95% CI = 0.5 to 0.7) and of major mechanical malfunction (OR = 0.7, 95% CI = 0.6 to 0.9) compared with patients who planned to undergo staged-bilateral arthroplasty. The unadjusted thirty-day incidence of death or a coronary event was 3.2 events per thousand patients higher after simultaneous-bilateral arthroplasty than after staged-bilateral arthroplasty, but the one-year incidence of major joint infection or major mechanical malfunction was 10.5 events per thousand lower after simultaneous-bilateral arthroplasty. CONCLUSIONS Simultaneous-bilateral total knee arthroplasty was associated with a clinically important reduction in the incidence of periprosthetic joint infection and malfunction within one year after arthroplasty, but it was associated with a moderately higher risk of an adverse cardiovascular outcome within thirty days. If patients who are at higher risk for cardiovascular complications can be identified, simultaneous-bilateral knee arthroplasty may be the preferred surgical strategy for the remaining lower-risk patients.

Incidence of Carpal Tunnel Release: Trends and Implications Within the United States Ambulatory Care Setting

PURPOSE To investigate the changes, trends, and implications of carpal tunnel release (CTR) surgery within an ambulatory setting over the past decade in the United States. METHODS We undertook an analysis of ambulatory surgery center CTR cases using data from the National Survey of Ambulatory Surgery. The Centers for Disease Control and Prevention carried out this survey in 1996, and again in 2006. We searched the cases with the procedure codes indicative of CTR. RESULTS The number of CTR procedures increased by 38% (from 360,000 to 577,000) between 1996 and 2006. In 1996, 16% of all ambulatory CTRs were performed in freestanding ambulatory surgery centers (hospital-based centers were 84%), and the proportion increased to 49% in 2006. By 2006, greater than 99% of CTRs were performed in an ambulatory setting. There was a significant increase in women aged 50 to 59 years of age undergoing CTR. CONCLUSIONS The minimal invasiveness of CTR combined with the advent of ambulatory care facilities has made CTR a predominantly outpatient procedure. In contrast to other reports, our study demonstrated a higher incidence of CTR within the United States in 2006 compared with 1996. Elderly women, in particular, with CTS were 3 times more likely to be treated surgically than other age groups. Further study is needed to better define factors influencing CTR indications. TYPE OF STUDY/LEVEL OF EVIDENCE Prognostic II.

Hip fractures in the United States: 2008 nationwide emergency department sample

To evaluate the recent epidemiology of hip fractures in the US.

Morbid Obesity and Excessive Hospital Resource Consumption for Unilateral Primary Hip and Knee Arthroplasty

Two objectives of this study were (i) to estimate the number of primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) performed on morbidly obese people in the United States, and (ii) to estimate the economic impact of morbid obesity on hospital resource use. In 2006, approximately 2.9% (6713 cases) of primary THA and 4.2% (20,964 cases) of primary TKA recipients were diagnosed as morbidly obese. Despite the controversy associated with increased infection risk and failure rate, a large number of morbidly obese people seem to consider that the benefits outweigh the risks. When sex, age, race, and primary payer were held constant, the hospital resource consumption for unilateral primary THA and TKA was 9% (

Comparison of Surgical Outcomes and Implant Wear Between Ceramic-Ceramic and Ceramic-Polyethylene Articulations in Total Hip Arthroplasty

1432) and 7% (

Injection of the subacromial bursa in patients with rotator cuff syndrome: a prospective, randomized study comparing the effectiveness of different routes.

1025) higher among morbidly obese patients than among nonobese patients, respectively.