Quality and Quantity of the Elbow Arthroscopy Literature: A Systematic Review and Meta-Analysis
The purpose of this article is to perform a systematic review and meta-analysis of elbow arthroscopy literature to answer the following questions: “Across the world, what demographic of patients are undergoing elbow arthroscopy, what are the most common indications for elbow arthroscopy, and how good is the evidence?”
The authors hypothesized that patients who undergo elbow arthroscopy will be chiefly age <40 years, the most common indication for elbow arthroscopy will be a release/débridement, and the evidence regarding elbow arthroscopy will be poor. Also, no significant differences will exist in elbow arthroscopy publications, subjects, outcomes, and techniques based on continent/country of publication.
A systematic review was registered with the International Prospective Register of Ongoing Systematic Reviews (PROSPERO) and performed with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using 3 publicly available databases. Therapeutic clinical outcome investigations reporting arthroscopic elbow outcomes with levels of evidence I-IV were eligible for inclusion. All study, subject, and surgical technique demographics were analyzed and compared between continents and countries. Statistics were calculated using 1-way analysis of variance (ANOVA) to compare between continents and Pearson’s correlation coefficients to evaluate changes over time.
In total, 112 studies were included (3093 subjects; 3168 elbows; 64% male; mean 34.9 ± 14.68 years. Mean 33.4 ± 26.02 months follow-up. Most studies were level IV evidence (94.6%) and had a low Modified Coleman Methodology Score (MCMS) (mean 28.1 ± 8.06). From 1985 through 2013, the number of publications significantly increased with time (P = .004) in all continents. The 3 most common indications for elbow arthroscopy were osteochondritis dissecans (OCD), lateral epicondylitis, and release and débridement. The number of reported cases for the 3 most common indications significantly increased over time but did not differ between regions (P > .05 in all cases). Thirty-two studies (28.6%) reported clinical outcomes, the most common of which was the Mayo Elbow Performance Score, reported in 9.8% of studies. The quantity, but not the quality, of arthroscopic elbow publications has significantly increased over time. Most patients undergo elbow arthroscopy for lateral epicondylitis, OCD, and release and débridement. Pathology and indications do not appear to differ geographically with more men undergoing elbow arthroscopy than women.
Discussion
Elbow arthroscopy is an evolving surgical procedure that is used to treat intra- and extra-articular pathologies of the elbow. Outcomes of elbow arthroscopy for certain conditions have generally been reported as good, with improvements seen in pain, functional scores, and range of motion.6,15-17 The authors’ hypotheses were mostly confirmed in that the average age of patients undergoing elbow arthroscopy was <40 years, release/débridement was one of the most common indications (along with lateral epicondylitis and OCD), and the general evidence for elbow arthroscopy was poor. Also, there were almost no differences between continents/countries related to patient indications, preoperative imaging, anesthesia choice, indications, postoperative protocols, and outcomes (although the number of studies that reported outcomes was low and could have skewed the results), with the exception of a higher number of preoperative MRI scans in Asia. Some of the notable findings of this study included: 1) the number of studies published on elbow arthroscopy is significantly increasing with time, despite a lack of improvement in the level of evidence; 2) the majority of studies on elbow arthroscopy do not report a surgical outcome score; and 3) the number of reported cases for the 3 most common indications significantly increased over time (OCD, P = .005; lateral epicondylitis, P = .044; release and débridement, P = .042) but did not differ between regions (P > .05 in all cases).
The indications for elbow arthroscopy have grown dramatically in the past 2 decades to include both intra- and extra-articular pathologies.18 Despite this increase in the number of indications for elbow arthroscopy, the study did not find a significant difference between countries/continents in the indications each used for elbow arthroscopy patients. There was a trend towards an increase in OCD cases in all continents, especially Asia (Figure 4), with time. Interestingly, while not statistically significant, there was variation among countries for surgical indications. In North America, removal of loose bodies accounts for 18% of patients, while in Europe this accounted for only 9% and in Asia for 1%. Post-traumatic stiffness was the indication for elbow arthroscopy in Europe in 19% of patients vs 7% in North America and 10% in Asia. In Asia, OCD accounts for 40% of arthroscopies, 7% in Europe, and 14% in North America (Figure 4) (Table 3).
This study demonstrated that the mean increase in elbow extension gained after surgery in North America was significantly greater when compared with studies from Asia, but the gain in flexion, pronation, and supination was similar across continents. The underlying cause of this difference in improvement in elbow extension between nations is unclear, although differences in diagnosis could account for some variation. This study did not examine differences in rehabilitation protocols, and certainly, it is plausible that protocol variations by country could account for some discrepancy. Furthermore, differences in functional needs may vary by continent and could have driven this result.
This study found no routine reporting of outcome scores by elbow arthroscopy studies from any continent, and that when outcome scores are reported, there is substantial inconsistency with regard to the actual scoring system used. No continent reported outcome scores in more than 40% of the studies published from that area, and the variation of outcome scores used, even from a single region, was large. This makes comparing clinical outcomes between studies difficult, even when performing identical procedures for identical indications, because there is no standardized method of reporting outcomes. To allow comparison of studies and generalizability of the results to different populations, a more standardized approach to outcome reporting needs to be instituted in the elbow arthroscopy literature. To date, there is no standardized score that has been validated for reporting clinical outcomes after elbow arthroscopy.19 Hence, it is not surprising that there were 16 different outcome scores reported throughout the 112 studies analyzed in this review, with the most frequent score, the MEPS, reported in a total of 10 studies. As medicine moves towards pay scales that are based on patient outcomes, it will become more important to define a clear outcome score that can be used to assess these patients, and reliably report scores. This will allow comparison of patients across nations to determine the best surgical treatment for different clinical problems. A validation study comparing these outcome scores to determine which score best summarizes the patient’s level of pain and function after surgery would be beneficial, because this could identify 1 score that could be standardized to allow comparison among reported outcomes.
Limitations
This study had several limitations. Despite having 2 authors search independently for studies, some studies could have been missed during the search process, introducing possible selection bias. Including only published studies could have introduced publication bias. Numerous studies did not report all the variables the authors examined. This could have skewed some results, and had additional variables been reported, could have altered the data to show significant differences in some measured variables. Because this study did not compare outcome measures for varying pathologies, conclusions cannot be drawn on the best treatment options for different indications. Case reports could have lowered the MCMS score and the average in studies reporting outcomes. Furthermore, the poor quality of the underlying data used in this study could limit the validity/generalizability of the results because this is a systematic review, and its level of evidence is only as high as the studies it includes. Because the primary aim was to report on demographics, this study did not examine concomitant pathology at the time of surgery or rehabilitation protocols.
Conclusion
The quantity, but not the quality, of arthroscopic elbow publications has significantly increased over time. Most patients undergo elbow arthroscopy for lateral epicondylitis, OCD, and release and débridement. Pathology and indications do not appear to differ geographically with more men undergoing elbow arthroscopy than women.
