Influence of Training Background on Elbow Arthroplasty Case Numbers: An Analysis of the American Board of Orthopaedic Surgery Part II Oral Examination Case List Database

Abstract

Introduction:

This study aimed to evaluate the influence of training background on the frequency and indications of elbow arthroplasty performed by early-career surgeons.

Methods:

A review of the American Board of Orthopaedic Surgery Part II Oral Examination Case List database from 2010 to 2021 was completed. The number of cases performed by surgeons from each individual training background were calculated and compared with the total number of surgeons who completed each fellowship during the study period.

Results:

Hand surgeons performed the most elbow arthroplasty cases (132, 44%), but a higher percentage of shoulder/elbow surgeons performed elbow arthroplasty in comparison (15% vs. 7%). The mean number of TEA cases performed by shoulder/elbow surgeons was significantly higher than in other subspecialties (P < 0.01). However, when comparing only surgeons who performed elbow arthroplasty during the board collection period, there was no significant difference between training backgrounds (P = 0.20).

Discussion:

While hand surgeons performed the most elbow arthroplasty cases, a higher percentage of shoulder/elbow surgeons performed elbow arthroplasty during the study period. The high prevalence of distal humerus fracture as an indication for arthroplasty reflected a shift in indications and was not related to training background.

Elbow arthroplasty has undergone many changes in design and indications since Dee introduced the first modern hinged, cemented total elbow arthroplasty (TEA) design in the early 1970s.¹ These advancements include the evolution of fully constrained to nonconstrained and finally to present-day semiconstrained and convertible prostheses as the understanding of elbow biomechanics and modes of failure were elucidated over the past few decades.² Historically, elbow arthroplasty was developed primarily to address advanced joint destruction, and most long-term studies on performance have been in the rheumatoid/inflammatory population.³ However, indications have expanded to incorporate select patients with end-stage osteoarthritis,⁴ posttraumatic arthritis,⁵ unreconstructable distal humeral fractures,⁶ and distal humeral nonunions.⁷

As the indications for elbow arthroplasty have evolved and expanded, there has been an associated increase in the number of TEAs being performed over the past 30 years.^8-10 Interestingly, conflicting forces influence this trend. Samdanis et al⁸ reported a drop in the incidence of TEA performed for inflammatory arthritis, hypothesizing that this may be influenced by the more widespread use of disease-modifying antirheumatic drugs to treat these diseases. They propose that the concomitant rise in TEAs performed to treat severe distal humerus fractures is responsible for the overall increase in TEA procedures. Unsurprisingly, they also report that revision TEA incidence has increased.

Despite the increased use and expanded indications for elbow arthroplasty, no formal curriculum exists for TEA training. In fact, multiple subspeciality fellowships within orthopaedics can have variable TEA exposure, including shoulder and elbow, hand, sports, and trauma. Nevertheless, experienced surgeons tend to have better outcomes throughout the field of orthopaedics. Jenkins et al¹¹ demonstrated that among elbow arthroplasty surgeons, those performing the procedure frequently have markedly increased implant survivorship. The goal of this study was to use the American Board of Orthopaedic Surgeons (ABOS) Part II Oral Examination Case List database to understand the characteristics of early-career orthopaedic surgeons performing TEA over the past decade. To possibly improve TEA training in the future, this analysis aims to determine if there is a relationship between fellowship choice and the performance of TEA, examine the indications for the procedure, and compare complication rates to historical data. The hypothesis for this study was that elbow arthroplasty case numbers for early-career surgeons would not be related to the training background.

Methods

This study is a review of the American Board of Orthopaedic Surgery Case List database querying the trends in elbow arthroplasty from 2010 to 2021. The database consists of surgical cases from a 6-month collection period submitted by early-practice orthopaedic surgeons taking Part II of the ABOS initial board certification examination. A research proposal was submitted to the ABOS requesting information for all cases submitted using the following CPT codes: 24363 (arthroplasty; elbow, with distal humeral and proximal ulnar prosthetic replacement; total elbow), 24370 (revision of TEA, including allograft when performed; humeral or ulnar implant), and 24371 (revision of TEA, including allograft when performed; humeral and ulnar implant). Additional information collected for each case included patient sex, patient age, surgeon fellowship training, International Classification of Diseases (ICD) codes associated with preoperative diagnosis, and documented postoperative complications/readmissions.

Cases performed by surgeons who had completed multiple fellowships were counted separately for each fellowship the surgeon had completed. In addition, specific ICD-9 and ICD-10 codes were categorized to identify common indications for primary elbow arthroplasty and determine their frequency (Table 1). Finally, the complication rates of the procedures were calculated based on reported postoperative complications. In the ABOS database, complications were reported throughout the duration of the study period, but readmissions and revision surgeries related to the procedure were not specifically noted until 2013. Complications were reported if noted within the 6-month case collection process while revision surgeries and readmissions were noted if they occurred within 90 days after the index surgery.

Table 1.

Demonstration of the Relevant ICD-9 and ICD-10 Codes Used to Categorize Cases Within Diagnoses of Interest When Applicable.

	Humerus Fracture	Inflammatory Arthritis	OA	PTOA
ICD-9	812	714	715	716.1
				905
ICD-10	S42	M05	M19.02	M19.1
	M80.02	M06		M19.2
	M80.82

OA = osteoarthritis, PTOA = posttraumatic osteoarthritis

Statistical Analysis

Statistical testing was conducted with calculator software from Social Science Statistics (www.socscistatistics.com). Given the nonparametric distribution of the number of cases performed by individual surgeons, one-way ANOVA testing was used to test for a relationship between the number of elbow arthroplasty cases performed and surgeon training across the fellowship training backgrounds of shoulder and elbow, hand and upper extremity, sports, and trauma. The Mann-Whitney U test evaluated for significant differences in the number of cases per surgeon when comparing between individual training backgrounds. Chi-square testing was used to assess for the differences in the proportion of elbow arthroplasty performed for acute trauma (distal humerus fracture) compared with common chronic indications (inflammatory/rheumatoid arthritis, osteoarthritis, and posttraumatic osteoarthritis) between surgeons of different training backgrounds. Spearman rank correlation was also used to assess for a change in the frequency of elbow arthroplasty during the study period.

Results

From 2010 to 2021, 8788 surgeons (annual mean: 732.3) were examined with 1,047,391 cases (annual mean: 87,283) submitted to the database. A total of 1398 hand and upper extremity fellowship-trained, 403 shoulder/elbow fellowship-trained, 810 trauma fellowship-trained, and 2253 sports fellowship-trained surgeons were included. During this period, surgeons submitted 259 primary and 39 revision TEA cases. One hundred twenty-one primary and 11 revision cases were performed by surgeons who had previously completed a hand and upper extremity fellowship, 87 primary and 16 revisions by surgeons with a shoulder/elbow fellowship background, 17 primary and no revisions by trauma fellowship-trained surgeons, and 22 primary and four revisions by surgeons who had competed a sports fellowship. Two hundred one surgeons performed primary TEA and 25 performed revision TEA. One hundred hand-trained (7%), 62 shoulder/elbow–trained (15%), 14 trauma-trained (2%), and 20 sports-trained (1%) surgeons performed primary elbow arthroplasty. Revision TEA was performed by 9 hand-trained (1%), 13 shoulder/elbow–trained (3%), 2 trauma-trained (<1%), and 4 sports-trained (<1%) surgeons (Table 2).

Table 2.

Number of Surgeons and Elbow Arthroplasty Cases Performed by Surgeons From Select Subspeciality Training Backgrounds

	Total Surgeons	TEA Surgeons	Cases	Cases/All Surgeons	Cases/TEA Surgeons
Hand	1,398	100 (7%)	121	0.07	1.21
Shoulder/elbow	403	62 (15%)	87	0.22	1.40
Trauma	810	14 (2%)	17	0.02	1.21
Sports	2253	20 (1%)	22	0.01	1.10

TEA = total elbow arthroplasty

A significant difference was observed in the number of TEA cases performed per surgeon between training backgrounds (P < 0.001). When evaluating between groups, there was a significant difference in the number of cases performed per surgeon among hand surgeons versus shoulder and elbow surgeons (P < 0.001), hand surgeons versus trauma surgeons (P < 0.001), hand surgeons versus sports surgeons (P < 0.001), shoulder and elbow surgeons versus trauma surgeons (P < 0.001), shoulder and elbow surgeons versus sports surgeons (P < 0.001), and sports surgeons versus trauma surgeons (P = 0.049). No significant difference in the number of elbow arthroplasty cases performed per surgeon was observed between training backgrounds when evaluating only the surgeons who had submitted elbow arthroplasty cases (P = 0.20).

A total of 226 primary TEAs were performed for the indications of humerus fracture, inflammatory arthritis, osteoarthritis, or posttraumatic osteoarthritis. Of these, 148 primary TEAs (65%) were performed for the indication of humerus fracture, 35 (15%) for rheumatoid arthritis, 27 (12%) for osteoarthritis, and 16 (7%) for posttraumatic osteoarthritis. 16 of 17 elbow arthroplasty cases (94%) performed for these indications by trauma-trained surgeons were for distal humerus fracture. In comparison, distal humerus fracture was the indication for elbow arthroplasty in 71 of 114 cases (62%) performed by hand surgeons, 50 of 78 (64%) performed by shoulder and elbow surgeons, and 13 of 21 (62%) performed by sports surgeons. No significant difference in the proportion of elbow arthroplasty performed for distal humerus fracture was found between training backgrounds (P = 0.07; Figure 1).

Figure 1.

Chart demonstrating distribution of primary total elbow arthroplasty case numbers by year for indications of interest. OA = osteoarthritis.

The number of primary and revision TEA cases performed each year during the study period is presented in Figure 2. No significant correlation was observed between year and total number of elbow arthroplasty cases performed during the study period (P = 0.052).

Figure 2.

Graph demonstrating elbow arthroplasty case numbers by year for the procedures of interest with linear trend lines demonstrated. TEA = total elbow arthroplasty.

In total, 178 complications were reported in 137 (46%) of the 298 patients included in the study (Table 3). Of the 224 elbow arthroplasty cases with readmission and revision surgery data collected, there were 16 revision surgeries (7%) and 20 readmissions (9%). We did not attempt to stratify complications by training background because of the lack of statistical power.

Table 3.

Evaluation of Reported Complications Across All Submitted Cases

	TEA (n = 259)	Revision TEA (n = 39)	Total (n = 298)
Bone fracture	21 (8%)	2 (5%)	23
Infection	14 (5%)	1 (3%)	15
Stiffness	18 (7%)	1 (3%)	19
Wound complication	17 (7%)	4 (10%)	21
Dislocation	0 (0%)	0 (0%)	0
Nerve injury	22 (8%)	2 (5%)	24
Vascular injury	1 (<0.5%)	0 (0%)	1
Tendon/ligament repair failure	2 (1%)	0 (0%)	2
Hematoma/seroma	4 (2%)	1 (3%)	5
Loss of reduction	2 (1%)	0 (0%)	2
Implant failure	3 (1%)	2 (5%)	5
Surgical unspecified	18 (7%)	3 (8%)	21
Medical complication	30 (12%)	1 (3%)	31
Anesthetic complication	2 (1%)	0 (0%)	2
Patient death	7 (3%)	0 (0%)	7
Overall	161 (62%)	17 (44%)	178

TEA = total elbow arthroplasty

Discussion

The results from this study do not support the hypothesis that the performance of elbow arthroplasty cases among ABOS Part II Oral Examination candidates is unrelated to training background because surgeons who completed hand and upper extremity or shoulder/elbow fellowship, particularly shoulder/elbow, performed markedly more elbow arthroplasty cases than of other subspecialities. Overall, hand and upper extremity surgeons performed the highest number of the elbow arthroplasty cases reported in the database. However, when evaluating case numbers for TEA on a per-surgeon basis, shoulder/elbow–trained surgeons performed a markedly higher number of cases (0.22 cases per surgeon) than of other subspecialities including hand and upper extremity. In addition, hand surgeons performed a markedly higher average number of elbow arthroplasty cases than trauma or sports fellowship-trained surgeons. These differences in case numbers when comparing all surgeons appear to largely be a function of the higher percentages of surgeons who completed shoulder/elbow or hand and upper extremity training that performed elbow arthroplasty in comparison to the other subspecialties. No significant difference was noted between subspecialties in the average number of elbow arthroplasty cases performed when comparing only between surgeons who performed elbow arthroplasty during their board collection period.

Classically, inflammatory arthritis is the leading indication for elbow arthroplasty, given the postoperative activity limitations after elbow arthroplasty. In a comprehensive systematic review of reports on TEA from 2003 to 2015 including 9,379 cases and 19 implant designs, Welsink et al¹² showed that rheumatoid arthritis was the reported indication in 70.1% of cases. However, disease-modifying antirheumatic drugs have markedly altered the natural course of joint destruction in several patients with inflammatory arthritis and deceased the number who ultimately require treatment with elbow arthroplasty.¹³ In addition, elbow arthroplasty has been supported as a viable option in the treatment of “unrepairable” distal humerus fractures, posttraumatic arthritis, and advanced osteoarthritis, leading to a change in the typical indication profile for elbow arthroplasty.^{6,14,15,16,17,18} While the study did not show a notable change in the number of elbow arthroplasties performed annually during the study period, the results of this study support previous studies showing a shift in indications from inflammatory arthritis toward the treatment of traumatic injuries because humerus fracture was the indication for most of the arthroplasties reported in the database.^9,11 This finding was observed across all subspeciality training backgrounds with no notable difference in the rate of elbow arthroplasty performed for the indication of distal humerus fracture between training backgrounds.

Although the complication rates of elbow arthroplasty are variable across previous literature, they are consistently higher than of the more common hip, knee, and shoulder arthroplasties.^19,20 This study demonstrated complications in 46% of patients and a 7% revision surgery rate in a relatively short follow-up period, reinforcing the elevated concern for postoperative complications after these procedures. While the complication rate reported in this study is higher than the complication rates reported in two recent systematic reviews of elbow arthroplasty, it is unclear if this finding is related to the prospective collection of complication outcomes in comparison with previous retrospective studies or a relatively inexperienced cohort of surgeons.^19,21 Jenkins et al¹¹ reported results from a Scottish arthroplasty database and demonstrated a markedly lower complication rate for surgeons who performed 10 or more elbow arthroplasties per year in comparison with lower volume surgeons. No surgeons included in this study reported 10 cases, and the average number of cases reported by surgeons who performed elbow arthroplasty during board collection was less than two, which may have contributed to a higher complication rate. Complications within this study were individually reported to the ABOS database by surgeons following their patients at the completion of the collection period while the study by Jenkins et al¹¹ identified complications through review of a national database based on major medical complications, septic arthritis, dislocations, fracture, or other arthroplasty episodes during the study period. The different methods of complication identification and reporting may affect the differences in complication rate as well.

This study identifies important trends in elbow arthroplasty because it relates to surgeon training and procedure indications. Because previous studies have shown that complication rates after elbow arthroplasty may be affected by surgeon experience, it will be increasingly important to identify training pathways beyond residency for surgeons who are interested in elbow arthroplasty. The information presented in this study may be helpful for fellowship programs or prospective fellowship applicants to identify the training fields associated with performing elbow arthroplasty in practice. In addition, this study redemonstrates the increasing trend of elbow arthroplasty for the treatment of distal humerus fractures, supporting additional research into identifying the ideal indications for elbow arthroplasty after fracture.

However, this study has several weaknesses. As a database study, the results are dependent upon appropriate data collection and coding by examinees, which may affect the results. We also note that practice patterns can change over the course of a surgeon's career, and a relative lack of reported elbow arthroplasty cases reported during board collection does not necessarily mean that a surgeon will refrain from regularly performing elbow arthroplasty later in their career as their practice changes over time. Similarly, surgeons with less established practices may tend to see a higher percentage of acutely traumatized patients in comparison to patients who present electively potentially effecting the reporting of elbow arthroplasty indications in this study. In addition, because the follow-up period of 6 months is quite short for the evaluation of arthroplasty results, it is likely that this study underreports complication and revision surgery rates.

In conclusion, this study demonstrates that while hand and upper extremity–trained surgeons performed the highest number of TEA cases, shoulder/elbow–trained surgeons performed the highest number of revision TEA cases and markedly more elbow arthroplasty cases on average during their case collection period in preparation for the ABOS Part II Oral Examination. In addition, the high rate of distal humerus fracture as an indication for arthroplasty reflected a shift in indications and was not markedly related to training background. Overall, elbow arthroplasty is infrequently performed by early-career orthopaedic surgeons while collecting cases for the ABOS Part II Oral Examination, and complication rates continue to remain high for these surgeries.