The Characteristics of Surgeons Performing Total Shoulder Arthroplasty: Volume Consistency, Training, and Specialization
Dr. Zmistowski and Dr. Warrender are orthopedic surgery residents, Thomas Jefferson University, Philadelphia, Pennsylvania. Mr. Livesey and Mr. Girden are medical students, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania. Dr. Williams is Professors of Shoulder and Elbow Surgery and Dr. Namdari is an Associate Professor of Orthopedic Surgery, Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
Authors’ Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article.
Address correspondence to: Surena Namdari, MD MSc, Rothman Orthopaedic Institute, 925 Chestnut Street, 5th Floor, Philadelphia, PA 19107 (tel, 267-339-3738; email, email@example.com).
Am J Orthop. 2018;47(12). Copyright Frontline Medical Communications Inc. 2018. All rights reserved.
Total shoulder arthroplasty (TSA) has proved a cost-effective, reproducible procedure for multiple shoulder pathologies. As utilization of TSA continues to grow, it is important to investigate procedure diversity, training, and other characteristics of surgeons performing TSA. To identify surgeons performing TSA in the Medicare population, the Medicare Provider Utilization and Payment Databases from 2012 through 2014 were used. This dataset includes any provider who bills Medicare >10 times with a single billing code. A web-based search was performed for each physician performing >10 TSA in all years of the study to identify their surgical training characteristics. Between 2012 and 2014, 1374 surgeons (39 females [2.8%]) performed >10 TSA in Medicare patients in at least 1 year (71,973 TSA). Only 44.3% (609/1374) of surgeons met this threshold for all 3 years (55,538 TSA). Of these 609 surgeons, 191 (31.3%) were shoulder and elbow fellowship trained (21,444 TSA). Shoulder and elbow fellowship-trained surgeons were at earlier points in their careers and practiced in large referral-based centers with other surgeons performing TSA. In addition to TSA, surgeons performed other non-arthroplasty shoulder procedures (80.2% of surgeons), total knee arthroplasty (46.3%), repairs of traumatic injuries (29.8%), total hip arthroplasty (27.8%), non-arthroplasty knee surgeries (27.2%), elbow procedures (19.6%), and hand surgery (15.4%) during the study period. With less than one-third of TSA performed by shoulder and elbow fellowship-trained surgeons with consistent moderate-volume practices, the impact of consistent high-volume practices and targeted fellowship training on quality must be determined.
With the adoption of reverse shoulder arthroplasty, utilization of total shoulder arthroplasty (TSA) has increased substantially over the last decade.1–3 Such increases are likely secondary to an aging population, increased comfort with the procedure, and the adoption of broadened indications for reverse shoulder arthroplasty, especially in the setting of proximal humerus fractures in the elderly.4–7 Between 2012 and 2014 alone, the number of surgeons performing >10 TSA in Medicare patients annually increased by 28.6% (824 to 1060 surgeons) providing a 26.6% (20,824-26,365 procedures) increase in national volume in the Medicare population.2 With this boom in utilization, scrutiny of this now routine procedure and those performing it is necessary.
Prior reviews have demonstrated a strong link between surgeon and hospital TSA volume and outcomes of the procedure.8–10 Somerson and colleagues11 investigated fellowship training among surgeons performing TSA in 2012 and found that only 28% had completed a shoulder and elbow fellowship. In addition to prior analyses2, 12, Somerson and colleagues confirmed a persistent geographic variation in utilization of TSA.11 In conjunction with the evolution of shoulder arthroplasty, dedicated shoulder and elbow fellowship training has expanded. With a shift toward specialization in care, nearly 90% of orthopedic surgery residents plan to pursue shoulder and elbow fellowships, comprising 4.6% of (42/897) of available positions.13
What remains unknown is the specialization of surgeons performing TSA, the regularity of their arthroplasty volume, and trends in TSA specialization over time. Therefore, this study aims to (a) identify surgeons performing shoulder arthroplasty and cohort changes over time, (b) determine the case profile of surgeons consistently performing shoulder arthroplasty, and (c) establish the characteristics of shoulder arthroplasty surgeons with a specific focus on fellowship training.
Prior to collecting surgeon-specific data, we identified surgeons performing TSA through the Centers for Medicare and Medicaid Services’ public release of “Medicare Provider Utilization and Payment Data: Physician and Other Supplier.”14 Datasets from 2012, 2013, and 2014 were used to identify all surgeons performing >10 TSAs (Current Procedural Terminology [CPT] Code 23472) during at least 1 of those years. This dataset provides the name, identification number, address, and all billing (by volume) for each unique CPT code submitted ≥10 times in a calendar year.
Once the cohort of surgeons had been generated, the number of surgeons consistently performing TSA year-over-year was determined. This allowed for an analysis of the consistency with which surgeons are performing moderate- to high-volume TSA. To form a case profile of surgeons performing TSA and observe how this shifted over time, a count and a description of each CPT code submitted by each surgeon was identified. To maintain patient privacy, only those claims made >10 times are reported for a provider (both physicians and physician-extenders are included in this dataset). First, all CPT codes were reviewed and tagged as surgical or non-surgical events. Then, every procedural CPT code identified was reviewed and categorized based upon anatomic location and procedure (eg, total knee arthroplasty [TKA]). It is important to note that all claims in this dataset are limited to those patients participating in Medicare’s fee-for-service program.
Specialization was defined as the number of categorized procedures as a percentage of all procedures performed on Medicare patients. The trends for national, regional, and individual specialization of TSA, arthroplasty (major joint), and shoulder procedures were determined.
To investigate the characteristics of surgeons consistently performing TSA, all surgeons performing a minimum of 11 TSA in Medicare fee-for-service beneficiaries in all years between 2012 and 2014 were identified. Such surgeons were defined as consistent TSA surgeons. Investigation of this cohort included a web-based search of their self-reported post-graduate fellowship training and year of graduation from medical school. Using these data, the percentage of surgeons performing TSA who underwent formal shoulder and elbow training was determined. In addition, the impact of fellowship training on shoulder specialization and practice location was determined. Surgeons who had completed multiple fellowships were categorized under all of them. As such, there may be some duplication of surgeons in the comparisons. In addition, other potential characteristics of shoulder and elbow fellowship-trained surgeons were investigated: number of regional shoulder surgeons, urban area, total number of Medicare beneficiaries, average reimbursement for TSA, ethnicity of Medicare beneficiaries, and percentage of Medicare patients eligible for Medicaid. Geographic regions were defined by the Dartmouth Atlas and assigned by hospital referral region.15 These defined regions were used to assess the beneficiaries (number and characteristics) that individual surgeons were likely serving. The United States Census Bureau characterization of zip code-based regions as urban areas (population >50,000), urban clusters (2500 to 50,000), and rural region (<2500) was used to categorize practice location.16
Descriptive statistics were used initially to report these findings. To analyze predictors of utilization and specialization, comparative statistics were undertaken. For comparison of binomial variables between groups, a χ2analysis was utilized. For continuous variables, data normality was assessed. A skewness and kurtosis <2 and 12, respectively, was considered to represent parametric data. For parametric data, the mean was reported; conversely, the median is reported for non-parametric data. To assess continuous variables between groups, a t test or a Wilcoxon rank-sum test was used for parametric and non-parametric distributions, respectively.
Between 2012 and 2014, 1374 surgeons (39 females [2.8%]) performed >10 TSA in Medicare patients in at least 1 year, for a combined total of 71,973 TSAs (Table 1). In 2012, only 834 surgeons (13 females [1.6%]) performed a minimum of 10 TSA in Medicare patients (21,137 arthroplasties; 25.3 per surgeon). This increased to 1078 surgeons (33 females [3.1%]; P = .04) performing 26,865 TSA (24.92 per surgeon) in 2014. Utilization of non-physician assistants in TSA also increased significantly over this period, with 307 assisting in 6885 TSAs (22.4 per provider) in 2012 and 465 assisting 10,433 TSA (22.4 per provider) in 2014. When all procedures were considered, including those performed at outpatient visits, 1319 physicians (95.9% of cohort) were active in 2012—providing either surgical procedures or outpatient consults to the Medicare population. Yet, only 63.2% performed >10 TSA in Medicare patients. The number of active surgeons performing TSA increased to 79.6% (1078/1353) in 2014 (P < .001).
In addition to TSA, this cohort of surgeons submitted 240 unique CPT codes with case volumes >10 annually over the 3-year study period. Of these, 80.2% (1102/1374) of surgeons performed non-arthroplasty shoulder procedures on Medicare patients, for a combined total of 202,335 procedures over the 3-year study period (Table 2). A significant proportion of these procedures were arthroscopic debridement (60,014 procedures performed by 908 surgeons) and arthroscopic rotator cuff repair (47,089 procedures performed by 809 surgeons). Just under half (49.1%; 674/1374) of surgeons performing TSA also performed TKA during this period (77,873 arthroplasties). Fewer surgeons (27.8%; 382/1374) performed total hip arthroplasty during this period (27,322 arthroplasties). Other procedure types that this group of surgeons routinely performed on Medicare patients were repairs of traumatic injuries (29.8%), non-arthroplasty knee surgeries (27.2%), elbow procedures (19.6%), and hand surgery (15.4%). By case load, non-arthroplasty shoulder procedures consisted of 43% of Medicare volume over the study period (Figure 1). Between 2012 and 2014, the average proportion of Medicare cases that were shoulder arthroplasties increased from 13.8% (21,137/152,862) to 16.7% (26,865/160,851; P = .001). Shoulder arthroplasty constituted 100% of the Medicare surgical case volume for 67 (4.9%; 67/1374) of the surgeons.
Only 44.3% (609/1374) of surgeons performed TSA in a minimum of 11 Medicare patients in all 3 years of the study period (consistent providers of TSA), providing a total of 55,538 TSA (77.2%; 55,538/71,973). When fellowship training was evaluated, 191 (31.4%; 191/609) of these surgeons were shoulder and elbow fellowship trained (21,444 TSA; 38.6%; Table 3). More than one-third (36.6%; 223/609) had completed a sports surgery fellowship (18,899 TSA; 34.0%). Surgeons trained in hand surgery (12.5%; 76/609) and adult reconstruction (5.3%; 32/610) also made contributions to meeting the TSA demand with 6971 (12.6%) and 2485 (4.5%) TSA, respectively. One-fifth of this cohort (18.1%; 110/609) had unknown fellowship training: they either reported no fellowship (13.6%; 83/609) or did not specify the type of training (4.4%; 27/609). Shoulder and elbow fellowship-trained surgeons performed more TSA (median: 89.0 TSA per surgeon between 2012 and 2014) than surgeons without shoulder and elbow fellowship training (median: 67.0 TSA per surgeon; P < 0.001). More than one-third (37%) of shoulder and elbow fellowship-trained surgeons’ surgical case volume was comprised of TSA, with an additional 35% from non-arthroplasty shoulder procedures (Figure 2). In order for the current supply of shoulder and elbow fellowship-trained surgeons to meet the Medicare TSA demand, each fellowship graduate would have to perform 140.6 TSA in Medicare patients annually. Shoulder and elbow fellowship-trained surgeons were more likely to practice in referral regions with an increased Medicare population (P < .001), an increased number of surgeons performing TSA (P < .001), and a higher proportion of Medicaid-eligible patients (P = .01; Table 4). Shoulder and elbow fellowship-trained surgeons (18.7 years post-medical school graduation) were also earlier in their careers than other consistent TSA surgeons (23.1 years post-graduation; P < .001).
Utilization of TSA has continued to rise; however, access to this cost-effective procedure was recently demonstrated to be limited.11 In a separate analysis, we established the continued rise in use of TSA in the Medicare population, coupled with an increase in the number of surgeons routinely performing TSA.2 Multiple analyses have demonstrated the importance of high-volume surgeons and hospitals familiar with the intricacies of shoulder arthroplasty concepts in minimizing complications, improving the quality and decreasing the cost of TSA.6,10,17 Specifically, Singh and colleagues18 demonstrated from a multi-center registry that surgeons and hospitals with greater shoulder arthroplasty volumes had decreased intra-operative blood loss, operative time, and hospital length of stay. As the demand for TSA, both anatomic and reverse, continues to rise, it is imperative that the healthcare delivery system is optimized to provide the best possible care. Before we can determine whether specialized training in shoulder arthroplasty influences surgical outcomes, characteristics and training of surgeons performing TSA should be described.
The number of surgeons performing >10 TSA in the Medicare population rose significantly between 2012 and 2014 (29.3%). However, the number of TSAs per surgeon over this time period remained consistent (approximately 25 per surgeon). Furthermore, the increase in the number of surgeons performing a reportable volume of TSA by 2014 was from the addition of already active surgeons (ie, the growth in TSA was not from the addition of newly trained arthroplasty surgeons but originated from the existing orthopedic surgeon workforce). In a recently published analysis, Somerson and colleagues, 11 using this same dataset, demonstrated persistent limitations in access to high-volume TSA surgeons. In a more recent analysis, we showed that while still lacking for some patients, access to a high-volume TSA surgeon has improved significantly over the past 3 years, with 96.9% of the United States population residing within 200 kilometers of a high-volume TSA surgeon (>20 Medicare cases).2 This analysis validates those findings, with the caveat that the average annual volume per surgeon is not increasing. What remains unknown, due to limitations of this dataset, is how many surgeons are not identified because they are performing ≤10 TSA each year or are performing TSA in non-Medicare patients.
With the specialization of healthcare delivery, specifically in orthopedics, it is imperative that mechanisms for providing specialty-focused care be established. However, the proportion of their practice that surgeons dedicate to TSA was unknown. This study demonstrates that this proportion is increasing. Including non-arthroplasty procedures, more than half (58%) of the procedures performed by this surgeon cohort were shoulder-specific. Furthermore, this analysis demonstrates that surgeons performing TSA have significant case diversity, including nearly half of the cohort performing TKA. Repeated evidence has demonstrated the effect of case volume on improved outcomes following orthopedic procedures.8,19–21 The pre-existing location-based model for delivering orthopedic care supports case diversity; however, this model continues to be challenged with high-volume centers of excellence and patient travel.22–24 Hip and knee arthroplasty experienced a similar surge in demand, with a subsequent shift in care to high-volume surgeons and centers.25 Shoulder and elbow fellowship-trained surgeons would need to nearly quadruple their current Medicare TSA volume to meet the entire current demand for TSA in the Medicare population (and this does not account for TSA performed by very low-volume surgeons not included in this cohort). With increased utilization of TSA, policymakers and the orthopedic community must determine the structure of delivery (centers of excellence or medium-volume disseminated throughout the country) that is optimal.
For those surgeons consistently performing TSA over the study period, fellowship training was diverse. While the current focus in orthopedics is on case volume, research in other specialties, namely general surgery, has provided repeated evidence that surgical specialization (more so than high case volume) provides improved outcomes.26–29 Furthermore, Leopold and colleagues30 demonstrated an inverse relationship between competency in performing a procedure and confidence in one’s ability to do so. In their study, educational intervention provided improved competency in the procedure. Less than one-third (29.8%) of TSA in this cohort were performed by a shoulder and elbow fellowship-trained surgeon consistently performing this procedure. Approximately another quarter (26.2%) were performed by consistent TSA surgeons trained in sports surgery. Meanwhile, 34.6% of TSA in this study cohort were performed by a surgeon who did not consistently meet the minimum threshold in all study years (16,435 TSA; 22.8%) or by a surgeon performing TSA without fellowship training (8,489 TSA; 11.8%). There has been a trend toward orthopedic subspecialty training with an increased demand for fellowship-trained surgeons.31 Despite this and the complexities of TSA, many continue to be performed by surgeons with an inconsistent volume and those without arthroplasty-specific fellowship training. The available evidence supports a push toward the fellowship-trained, high-volume TSA surgeon in providing reproducible high-quality shoulder arthroplasty care. For now, that surgeon is more likely to be earlier in his/her career and reside in large, referral-based centers surrounded by other surgeons performing TSA.
These findings must be considered in the light of the study limitations. First, this is a large publicly available database. While this type of database provides a unique opportunity to assess the geographic distributions and characteristics of orthopedic surgeons, specifically those performing TSA, it completely prevents any assessment of the relationship between these findings and quality. As such, while the reader may generate hypotheses regarding the implications of our findings on the quality of TSA delivery, the true effects cannot be determined. In the same vein, for the purpose of privacy, surgeons performing ≤10 TSA were not included in this dataset. This limitation prevents the identification of low-volume TSA surgeons. Also, it is likely that the observed increase in surgeons over time is likely a reflection of small increases in volume for surgeons already performing TSA. Lastly, a web-based search was undertaken to identify surgeons’ self-reported fellowship training. The results of this web-based search could not be validated, and it is possible that fellowship training, or the lack thereof, was mischaracterized and simply not obtainable through a web-based search. Furthermore, it is not possible to fully assess the extent of high-quality TSA training in these various fellowships.
In just the past decade, the utilization of TSA in the Medicare population has increased significantly. However, this increase was not achieved by the addition of highly specialized, high-volume surgeons but by the addition of many surgeons performing lower numbers of TSA surgeries. Furthermore, for those performing this cost-effective procedure, TSA constitutes a relatively small proportion of the surgeries they perform. Shoulder and elbow fellowship-trained surgeons currently account for a low percentage of the overall number of surgeons performing TSA. The implications of these findings must be considered and investigated.