Abstract
Background:
The Physician Payments Sunshine Act mandated the public reporting of all industry payments above a $10 value that are disbursed to physicians in the United States. Understanding the pattern of research payments among sports medicine orthopaedic surgeons (SMOSs) may help uncover potential biases and conflicts of interest, thereby promoting transparency and ethical conduct in musculoskeletal research.
Purpose:
To identify trends in private research payment distribution among SMOSs and to explore potential sources of disparity in the disbursement of research-related private funding.
Study Design:
Cross-sectional study.
Methods:
A cross-sectional analysis of the Open Payments Database was conducted between 2015 and 2021 to identify research payments disbursed to SMOSs. The h-index, number of publications, and years since completion of residency/fellowship training were collected from Scopus and the affiliated institution profile. Descriptive statistics were conducted for payments at the individual surgeon level. Wilcoxon rank-sum tests were utilized to assess the difference in median payment disbursement by surgeon sex. Nonparametric analyses were performed to identify predictors for payment.
Results:
During the study period, $81,268,687 in private research payments from 79 different industry companies was disbursed to 578 sports medicine surgeons at 397 different institutions. Sports medicine projects represented 23% of all orthopaedic payments, growing from 18% in 2015 to 26% in 2021. Male surgeons comprised 96% of all SMOSs receiving funding and collected 98% of the research payments. There was no statistically significant difference between the median male or female payment. However, the h-index, number of publications, and number of years in practice were all significantly associated with greater median private research payment in a univariate quantile model. The h-index and years out of training were positively associated with greater private research payment in the multivariate model.
Conclusion:
There was no statistically significant difference in median payment to SMOSs between sexes. A higher h-index and more years out of training were associated with receiving larger private research payments.
To promote financial transparency between physicians and the public, the Physician Payments Sunshine Act of the Affordable Care Act was passed in 2010. 33 This mandated that all industry payments >$10 US dollars (USD) be reported to the Centers for Medicare & Medicaid Services (CMS). To track the payments, the CMS established the Open Payments Database (OPD) and classified payments as either general payments or research payments.3,16 Research payments refer to payments used for research-related tasks, such as remunerating a doctor for their time dedicated to a study or supplying financial support for a research project. In contrast, general payments encompass remuneration for activities beyond the scope of research, such as expenses for food, speaking engagements, or consulting fees. 3 Previous studies have reported that orthopaedic surgeons receive a considerable share of industry payments in comparison with other specialties, although a small subset of practicing orthopaedic surgeons were recipients of such payments.6,18,35 However, these studies exclusively concentrated on general payments and did not investigate the characteristics of research payments.14,18,35,40,44 Moreover, the specific distribution of payments to orthopaedic surgeons has not been extensively examined.
A focused study examining payments made in 2016 to orthopaedic surgeons reported that male orthopaedic surgeons received 3 times more industry payments than female orthopaedic surgeons, even after controlling for faculty rank, years in practice, h-index, and subspecialty focus. 13 Furthermore, the h-index was positively correlated with greater industry payments to pediatric orthopaedic surgeons, 32 adult reconstruction surgeons, 5 hand surgeons, 22 shoulder and elbow surgeons,10,17 trauma surgeons, 11 and sports medicine surgeons. 4 Similarly, in neurosurgery, scholarly impact is positively correlated with receiving increased funding from industry. 8 In otolaryngology, sex has been reported to influence the distribution of payments, with men receiving more funding compared with women. 7
Although the h-index has been shown to correlate positively with industry payments and academic productivity in orthopaedic surgery, ¶ a specific analysis of the funding distribution to sports medicine orthopaedic surgeons (SMOSs) has not been conducted. Further analysis into how research payments are directed to SMOSs may help yield insight into potential biases and conflicts of interest between physicians and industry. Therefore, the goals of this study were to (1) report the trends in research payment distribution among SMOSs from 2015 to 2021, (2) identify any disparities in payments among SMOSs from 2015 to 2021, and (3) identify factors that serve as predictors of increased payments to SMOSs from 2015 to 2021.
Methods
Study Design and Setting
This study was a cross-sectional retrospective analysis of SMOSs practicing in the United States following the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) reporting guidelines. The CMS OPD was examined to identify private research payments disbursed to SMOSs between 2015 and 2021. 3 For each payment, the surgeon, their institution, the sponsoring industry company, and the financial amount of the payment were recorded. Payments were reported in USD and adjusted for inflation to December 2022, equivalent USD utilizing the Bureau of Labor Statistics’ Consumer Price Index Calculator. 41 The CMS OPD does not individually classify shoulder and elbow surgeons; therefore, this group of surgeons was included with SMOSs. Incomplete subspecialty entries were corrected based on information derived from the surgeon’s professional profile available through their institution.
Surgeon sex and number of years elapsed since training (ie, years in practice) were collected based on information from the surgeon’s professional profile. The number of years since training was calculated by utilizing 2023 as the minuend. The h-index and number of publications were collected from Scopus, a robust online repository for abstracts and peer-reviewed research articles. 37 The h-index is a metric that measures the impact of an author’s scholarly output utilizing the number of publications and the number of times that they’ve been cited. All incomplete entries for sex and subspecialty were corrected based on the information listed in the physician’s online institutional profile.
Statistical Analysis
Payment values were reported in USD and rounded to the nearest dollar. Descriptive statistics were conducted for payments disbursed to surgeons between 2015 and 2021. Wilcoxon rank-sum tests were utilized to assess the difference in payments between sexes. Nonparametric univariate quantile analysis and a multivariate generalized additive model utilizing the Gamma family with the log link function analysis were utilized to examine the impact of sex, h-index, years in practice, and number of publications on the distribution of research payments for all unique surgeons over the study period. Because of the nonparametric nature of the data, a quantile regression provides a method to understand how different variables affect the median of the distribution. A generalized additive model utilizing the Gamma family with the log link function allows identification of complex nonlinear relationships while accounting for skewed data by examining the percentage change in payments. Data processing and statistical analysis were performed using RStudio (Posit). P values <.05 were considered statistically significant.
Ethical Approval
This analysis utilized publicly available data and was therefore exempt from institutional review board approval.
Results
Trends in Private Research Payments
During the study period, $81,268,687 in private research payments from 79 different industry companies was disbursed to 578 sports medicine surgeons at 397 different institutions. Sports medicine research projects represented a total of 23% of all orthopaedic payments, growing from 18% in 2015 to 26% in 2021. The total payment to male surgeons was $6,416,001 in 2015, and it grew to 12,270,430 in 2021, while the total payment to female surgeons was $148,984 in 2015 and $100,748 in 2021 (Figure 1). A total of 188 unique SMOSs received $6,564,985 in private payments in 2015, compared with 249 surgeons receiving $12,371,178 in 2021 (Table 1). Funding to SMOSs grew at a nonmonotonic rate at a Mann-Kendall statistic of 5 (P = .548).
Male and female sports medicine orthopaedic surgery research funding from 2015 to 2021.
Sports Medicine Orthopaedic Surgeons Payments a
USD, US dollars.
Funding Analysis by Sex
During the defined study period (2015-2021), male SMOSs comprised 96% of SMOSs receiving private funding and received at least 98% of all available private research funding disbursed to SMOSs. The wide IQR of the median payment to SMOSs indicates that the data are skewed, with a small handful of surgeons receiving large portions of funding (Table 1).
The median payments disbursed to male SMOSs were $13,733 (IQR, $4941-$41,788) and $14,193 (IQR, $5079-$44,243) in 2015 and 2021, respectively. The median payments to male SMOSs fluctuated throughout the period, ranging from a low of $13,733 in 2015 to a high of $21,517 in 2018. In comparison, the median payments to female SMOSs were $6020 (IRQ, $1281-$23,920) and $4655 (IQR, $3477-$11,978) in 2015 and 2021, respectively. Similarly to their male counterparts, median payments to female SMOSs varied throughout the study period, ranging from a low of $4665 in 2015 to a high of $14,614 in 2017. For each individual year, there was no statistically significant difference in the median male and female payments. Overall, there were 552 unique male surgeons receiving funding and 26 unique female surgeons, with the median payment to male surgeons being $3631 greater; however, this difference was not statistically significant (Table 2).
Median Payment to Sports Medicine Orthopaedic Surgeons by Sex a
USD, US dollars.
Predictors of Funding
For the 578 unique SMOSs, when plotting the h-index against total funding, there was a general upward trend suggesting that academic productivity is associated with increased total funding (Figure 2A). Similarly, an increased number of publications (Figure 2B) and years out of training (Figure 2C) are associated with increased total funding. When plotting sex against total funding, male SMOSs generally receive more funding than female SMOSs, highlighting a potential overall sex disparity (Figure 2D).
Distribution of funding in relationship to (A) h-index, (B) number of publications, (C) years out of training, and (D) sex.
In the univariate quantile models, a 1-digit increase in h-index was associated with a $1633 increase in the median total payment (P < .001). Similarly, having an additional publication was associated with a $313 increase in the median total payment (P < .001). These findings indicate that academic productivity plays an important role in payment distribution. Each additional year out of training did not show any statistically significant relationship with the median total payment (P = .822). There was no statistically significant difference between male and female SMOSs in receiving payments solely due to sex (P = .996).
When accounting for other variables in the multivariate model, the h-index and years out of residency have significant nonlinear relationships with total payment. The h-index has a significant effect (P = .029) with an estimated degrees of freedom of 2.98, indicating that the h-index is associated with higher payments, but the rate of increases changes dependent on the range of h-index values. Years out of training had a significant impact (P = .001) with an estimated degrees of freedom of 4.74, indicating a more complex, nonlinear relationship with payments. Of importance, sex does not have a statistically significant effect on payments in this model (P = .136). Number of publications was excluded from the multivariate model due to multicollinearity with the h-index (variance inflation factor, 4.84) (Table 3).
Predictors of Private Sports Medicine Orthopaedic Research Payments a
All unique sports medicine orthopaedic surgeons over the study period were included in the analysis. NA, not applicable.
Number of publications was not included in the multivariate model due to multicollinearity with the h-index (variance inflation factor, 4.84).
Univariate analysis was performed utilizing quantile analysis.
Multivariate analysis was performed utilizing a generalized additive model using the Gamma family with a log link function.
Values in US Dollars.
Discussion
This study examined trends in private research funding among SMOSs and aimed to identify potential disparities as well as predictors for funding disbursed to surgeons. Between 2015 and 2021, $81,268,687 was invested in sports medicine orthopaedic surgery research from the private sector. Of all orthopaedic surgery research funding disbursed during that period, sports medicine funding constituted 23% of the payments and grew from 18% in 2015 to 26% in 2021. Men constituted at 96% of the surgeons receiving funding and received at least 98% of the funding per year. There was no difference between the median payment to male and female surgeons. In the multivariate model, h-index and years out of training were significantly associated with receiving greater private research funding. Academic institutions may also apply these results to create projections of private research funding disbursement that may be received by their SMOS faculty members. This type of effort could ensure that sports medicine research projects receive an appropriate level of institutional support, thereby optimizing the ability of qualified SMOSs to conduct their research efficiently and effectively.
Trends in Payments
Sports medicine orthopaedic funding has generally grown over the study period; however, this growth was not linear and not statistically significant. The amount of total research funding decreased in 2019 and 2020, potentially because of the COVID-19 pandemic, as this trend was observed in other medical fields as well.27,28 Furthermore, the number of SMOSs receiving funding increased over the study period, although the median payment did not drastically change. This increase in the number of surgeons receiving funding has been observed in other fields, possibly signaling a broader increase in physicians conducting privately funded research in recent years.19,21
Sports medicine orthopaedic surgery research has grown to represent one of the largest orthopaedic subspecialties receiving private funding. In 2021, sports medicine trailed only adult reconstruction, accounting for 26% of all orthopaedic funding disbursed in that year. As private funding for adult reconstruction research drops, sports medicine research funding continues to increase. 38
Sex Differences in Funding
Although there is no difference in the median payment between female and male SMOSs, indicating an equitable distribution of funding to those SMOSs who have received funding, there was a skewed distribution of SMOS sexes, with significantly more male SMOS researchers. A 2016 study analyzing total private funding, both general and research payments, concluded that female surgeons received 29% of private funding when controlling for faculty rank, h-index, and subspecialty. 13
With an increase in female SMOS participation in private research funding, it can logically be argued that with median payments being statistically different between sexes, female SMOSs would have an equivalent distribution of research funding. Furthermore, the first step for change would be increasing the total number of practicing SMOSs. A recent study examining the American Orthopaedic Society for Sports Medicine fellowship completion data from 2016 to 2021 identified that 11% of graduates (141/1268) were female. 23 It is fair to assume that the 11% figure is an improvement for previous years with the increased push toward gender equality. In addition, it is also fair to assume that this 11% figure does not indicate how many female SMOSs are pursuing academic or research roles. This paired with the current emphasis on research to more experienced and higher h-index researchers could account for some of the current discrepancy. As the number of female SMOSs is increasing, they will achieve more years of training and higher h-indexes, and this disparity will hopefully decrease.
Furthermore, sex inequality in surgery has been attributed to the lack of support, unequal opportunities, and societal pressures. 25 This inequity has been observed in other medical fields as well.7,8,29,30,39,42 For example, female pelvic medicine and reconstructive surgeons and neurosurgeons were less likely to receive industry funding and received less total funding than their male counterparts.8,39 Likewise, in otolaryngology, among the top 10% of surgeons based on h-index, 65% of men and 28% of women received industry funding, demonstrating a similar discrepancy. 7 Advocates argue that fostering greater sex equality can spur innovation.26,36 Thus, improving financial support to female SMOSs to participate in academic pursuits may help promote scientific discovery and development in the field of sports medicine.31,34,43
Increases in funding disbursed to female surgeons can be accomplished through system-based interventions such as enhanced institutional support, consistent diversity in clinical trials, and policies to ensure that female faculty members are provided equal opportunities compared with their male counterparts. Furthermore, increased female representation may inspire new generations of female scientists and clinicians, which will only continue to mitigate these academic inequities in the long term.
Predictors for Funding
The h-index and years out of training were the only significant predictors of increased funding in the multivariate model. It is well established that greater research productivity correlates with increased industry support in orthopaedic research. # Previous studies have indicated that a high h-index can be predictive of industry payments between $10,000 and $100,000 (OR, 1.63; P = .048) and payments >$100,000 (OR, 2.22; P < .001). 1 Although the median payment size to SMOSs was similar between sexes in this study, male sex is still a significant positive predictor of increased private research funding to SMOSs. Given that years out of training was significantly associated with increased funding in the multivariate model, it can be assumed that this discrepancy could be caused by the, on average, lower years out of training of female SMOSs. This can be assumed as there is a strong influx of women into orthopaedic surgery and more so into sports medicine, such that they would naturally have a lower number of years out of training. This discrepancy suggests that, even with similar median payment sizes, other factors related to sex contribute to the likelihood of receiving private research funding. Similarly, in neurosurgery and otolaryngology, female surgeons received less private funding compared with their male counterparts with a similar h-index.7,8
The h-index should therefore be utilized as an indicator for funding, as it is a harbinger of productive researchers that will provide a return on the funding investment. In a capitalist meritocratic society, aggregation of funding toward the most productive SMOSs is natural and can be seen as a parallel to the development of centers of excellence, which are specialized programs that concentrate talent and resources to specific medical areas of medicine.9,20,38
To decrease the current private sports medicine research funding discrepancy, the best first step would be to increase the number of women in orthopaedic surgery and in sports medicine orthopaedic surgery. This ought to be done by having more organizations like the Perry Initiative and the Ruth Jackson Orthopaedic Society to mentor future female orthopaedic surgeons. Furthermore, research grants for young investigators and female researchers can help level the current playing field and eventually decrease the funding discrepancy.
Limitations
This study has several limitations. First, the study is based on the data in the CMS OPD. There is no available data to indicate the number of SMOSs who applied for funding; therefore, it is impossible to know if women are being denied or accepted at rates different from men. Furthermore, there were many cases of payments to an individual in a group practice; however, there was no information on how those funds were distributed within the group. Therefore, the data are most likely an underrepresentation. 38
Second, the study’s accuracy depends on the accuracy of the data in the surgeon’s affiliated institution profile. Therefore, the accuracy of the study might have been compromised due to inaccurate information in their profile. A majority of orthopaedic surgeons did not have a subspeciality classification in the CMS OPD; therefore, manual subspecialty classification took place to identify sports medicine surgeons. This relies on the accuracy of the surgeon’s affiliated institution profile, which could invoke potential bias.
Conclusion
This study found a significant range in the distribution of payments for orthopaedic research, with a small group of surgeons receiving a large number of payments. While there were no statistically significant differences between the median payment to SMOSs between sexes, men received a majority of the funding. Furthermore, h-index and years out of training were significantly associated with a higher likelihood of receiving a larger amount of payments for research from private companies. These findings offer valuable insights into payment trends and characteristics in orthopaedic sports medicine research, to promote growth and equity in the field.
Footnotes
Final revision submitted February 4, 2025; accepted February 27, 2025.
One or more of the authors has declared the following potential conflict of interest or source of funding: H.P.G. has received education payments from Smith & Nephew. J.G.C. has received consulting fees from Medical Device Business Services and Smith & Nephew and education payments from Evolution Surgical, Rock Medical Orthopedics, and Smith & Nephew. S.M.S. has received consulting fees from Miach Orthopaedics, Moximed, Vericel, Smith & Nephew, and Flexion Therapeutics; honoraria from Vericel and JRF Ortho; and research support from Miach Orthopaedics and Moximed; is a paid presenter or speaker for Miach Orthopaedics, Moximed, Smith & Nephew, and Vericel; has stock or stock options in Smith & Nephew and Stryker; and is a board or committee member of Arthroscopy Association of North America. J.E.V. has received consulting fees from DePuy Synthes Products, Medical Device Business Services, and Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
Ethical approval was not sought for the present study.
