Using Pitch-Tracking Data to Identify Risk Factors for Medial Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers.

Background: Approximately 25% of Major League Baseball (MLB) pitchers undergo medial ulnar collateral ligament reconstruction (UCLR) during their careers. Purpose: To identify risk factors for UCLR that are specific to 2 subgroups of MLB pitchers: right (RHPs)- versus left-handed pitchers (LHPs) and starting (SPs) versus relief pitchers (RPs). Study Design: Case-control study; Level of evidence, 3. Methods: We included 109 MLB pitchers who had undergone UCLR between 2007 and 2019 and had sufficient preinjury data in the 3 years before surgery (T3, T2, T1). A 2:1 matched control cohort was selected for comparison. Pitch velocity, release location, and ball movement were compared between the UCLR and control cohorts in both subgroups in the years before surgery (RHPs vs LHPs and SPs vs RPs). Binary logistic regression was used to identify independent risk factors for UCLR. Results: The mean horizontal release location for the UCLR group was 5.8 cm more lateral than for the control group (P = .028). For all pitchers, every 2.5-cm lateral shift in release location in the years leading up to UCLR equated to a 3.7% increase in the odds of UCLR. For RPs, this risk was more substantial: a 5.8% increase in odds per 2.5 cm. SPs in the UCLR group demonstrated significantly different T1 horizontal release locations compared with SPs in the control group, though not to a statistically significant change over the 3 years before surgery. However, in the 3 years before surgery, the horizontal release location for RPs in the UCLR group moved 2.1 cm more lateral, as compared with 2.7 cm more medial for RPs in the control group (P = .007). For LHPs, a decrease in mean pitch velocity by 1 mph (1.6 km/h) in the years leading up to surgery increased the odds of UCLR by 45%. Conclusion: Increasing lateralization of release point in the years before surgery increased the risk of UCLR, specifically for relievers. Our findings add to the growing body of evidence that release location is an important variable in analyzing the risk of UCLR in MLB and that risk stratification may be dependent on pitcher characteristics such as position, handedness, and weight.

Primary versus revision total shoulder arthroplasty: comparing relative value and reimbursement trends.

BACKGROUND: Total shoulder arthroplasty (TSA) has been demonstrated to be an effective treatment for multiple shoulder pathologies. The purpose of our study was to compare the relative value units (RVUs) per minute of surgical time for primary and revision TSA. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify patients that underwent primary TSA, one-component revision TSA, and two-component revision TSA between January 1, 2015 and December 31, 2017 using current procedure terminology codes. RVUs were divided by mean operative time for each procedure to determine the amount of revenue generated per minute. Rates were compared between the groups using a one-way analysis of variance with post-hoc Tukey test. Statistical significance was set at p<0.05. RESULTS: When dividing compensation by surgical time, we found that two-component revision generated more compensation per minute compared to primary TSA (0.284±0.114 vs. 0.239±0.278 RVU per minute or $10.25±$4.11 vs. $8.64±$10.05 per minute, respectively; p=0.001). CONCLUSIONS: The relative value of revision TSA procedures is weighted to account for the increased technical challenges and time associated with these procedures. This study confirms that reimbursement is higher for revision TSA compared to primary TSA.

Trends in leadership at shoulder and elbow fellowships: a cross-sectional demographic review.

OBJECTIVE: To determine educational characteristics, trends, and demographics among shoulder and elbow fellowship leaders (FLs). BACKGROUND: Fellowship leaders in shoulder and elbow impart lasting impact on trainees and field development. Four previous studies have analyzed the characteristics and career path trends among orthopedic surgery subspecialty FLs (spine, adult reconstruction, trauma, and sports medicine). We characterized the educational backgrounds and demographic composition of all 40 FLs including fellowship directors (FD), fellowship co-directors (co-FD), and associate fellowship directors (associate FD) of 31 American Shoulder and Elbow Surgeons (ASES)-accredited shoulder and elbow fellowships in the United States. We additionally compiled the residency and fellowship institutions that trained FLs as framework for aspiring leaders in orthopedic surgery. METHODS: Using the American Shoulder and Elbow Surgeons (ASES) directory website page "ASES-Recognized Shoulder and Elbow Fellowship Programs," we identified all active shoulder and elbow fellowships within the United States as well as associated FL identifiers. Compiled data points include age, sex, ethnicity, residency/fellowship training location, time since education completion until FL appointment, length in FL role, personal research Scopus H-index, and major society and journal leadership position history. RESULTS: We analyzed data from all 40 active FLs across 31 ASES-accredited shoulder and elbow fellowships, encompassing 26 FDs, 13 co-FDs, and 1 associate FD. The majority of FLs (97.5%) were male whereas 2.5% were female, with racial/ethnic identification of 80.0% Caucasian, 10.0% Asian/Pacific Islander, and 10.0% Middle Eastern. The mean Scopus H-index of the FLs was 24.63 ± 16.43. The top residency programs for producing future FLs were the University of Pittsburgh, University of Pennsylvania, University of Nebraska/Creighton, Hospital for Special Surgery, and Brown University (all n = 2). The top fellowship programs for producing future FLs were Mayo Clinic (n = 6), Columbia University (n = 6), San Francisco/California Pacific (n = 4), and Washington University in St Louis (n = 4). CONCLUSION: Shoulder and elbow fellowship leaders graduate with increased frequency from certain fellowship programs with lesser correlation to residency institutions. Programs demonstrate high retention of prior trainees as future FLs. All FLs are distinguished by high indices of research productivity; however, demographic diversity remains limited, which is comparable to prior orthopedic subspecialty FL investigations.

Shoulder Hemiarthroplasty with Nonprosthetic Glenoid Arthroplasty: The Ream-and-Run Procedure.

¼: Glenoid component wear and loosening are the principal failure modes of anatomic total shoulder arthroplasty (aTSA). ¼: The ream-and-run (RnR) procedure is an alternative glenohumeral arthroplasty for patients who wish to avoid the risks and limitations of a prosthetic glenoid component. ¼: During the RnR procedure, the arthritic glenoid is conservatively reamed to a single concavity, while the prosthetic humeral component and soft tissues are balanced to provide both mobility and stability of the joint. ¼: The success of the RnR procedure depends on careful patient selection, preoperative education and engagement, optimal surgical technique, targeted rehabilitation, and close postoperative communication between the surgeon and the patient. ¼: While the RnR procedure allows high levels of shoulder function in most patients, the recovery can be longer and more arduous than with aTSA. ¼: Patients who have undergone an RnR procedure occasionally require a second closed or open procedure to address refractory shoulder stiffness, infection, or persistent glenoid-sided pain. These second procedures are more common after the RnR than with aTSA.

Imbalance in Axial-plane Rotator Cuff Fatty Infiltration in Posteriorly Worn Glenoids in Primary Glenohumeral Osteoarthritis: An MRI-based Study.

BACKGROUND: Fatty infiltration of the rotator cuff evaluated with CT has been associated with asymmetric glenoid wear and humeral head subluxation in patients with glenohumeral arthritis. The relationship between rotator cuff pathologic findings and abnormal glenoid wear plays an important role in determining the optimal surgical management of advanced glenohumeral osteoarthritis. Compared with CT, MRI has increased sensitivity for identifying rotator cuff conditions; therefore, prior studies using CT may have underestimated the association between fatty infiltration of the rotator cuff and abnormal glenoid wear. QUESTIONS/PURPOSES: (1) Compared with Type A glenoids, which muscles in which Walch subtypes have a greater degree of fatty infiltration using Goutallier scores? (2) What glenoid type is associated with greater imbalance in fatty infiltration, as measured by comparing Goutallier scores between the posterior and anterior rotator cuff muscles? (3) What is the correlation between glenoid version and fatty infiltration of the rotator cuff muscles? (4) Comparing Type B2 and B3 glenoids with Type A glenoids, after accounting for age and sex, is there an increase in fatty infiltration of the infraspinatus muscle? METHODS: A total of 129 shoulders from 129 patients undergoing anatomic total shoulder arthroplasty to treat primary glenohumeral osteoarthritis were retrospectively reviewed. Patients had an average age of 66.4 ± 9.3 years and an average BMI of 30.6 ± 6.7 kg/m2, and 53% (69 of 129) were men. All patients underwent MRI within 12 months before total shoulder arthroplasty to assess glenoid morphology and rotator cuff pathologic findings. Three reviewers assessed the images, and glenoid morphology was assigned using the modified Walch classification system (Types A1, A2, B1, B2, B3, C, and D). Fatty infiltration of the rotator cuff was classified using Goutallier scores. The examiners demonstrated moderate-to-good reliability using these classification systems; the Walch classification system had interrater reliability kappa coefficients (κ) from 0.54 to 0.69 and intrarater reliability κ from 0.60 to 0.64. Goutallier scores using the simplified classification system had interrater reliability κ from 0.64 to 0.68 and intrarater reliability κ from 0.64 to 0.79. Thirty-six percent (46 of 129) of the shoulders had posterior wear patterns (18% [23] were Type B2 glenoids; 18% [23] were Type B3 glenoids). The average Goutallier scores for each rotator cuff muscle were determined, and the amount of fatty infiltration was compared between the various Walch subtypes using independent t-tests. Axial-plane imbalance in fatty infiltration of the rotator cuff was assessed by determining the difference in the average fatty infiltration of the posterior rotator cuff muscles (infraspinatus and teres minor) and anterior rotator cuff muscles (subscapularis) and comparing the differences among the Walch subtypes using independent t-tests. The association between glenoid version and fatty infiltration was assessed using Pearson correlations. Finally, a multivariate logistic regression model was used to assess fatty infiltration of the rotator cuff among the various Walch subtypes while accounting for patient age and sex. RESULTS: Compared with Type A1 glenoids, Type B2 and B3 glenoids had an increased amount of fatty infiltration of the infraspinatus (1.6 ± 0.7 versus 0.7 ± 0.4; mean difference 0.9 [95% CI 0.7-1.2]; p < 0.001 and 1.8 ± 0.4 versus 0.7 ± 0.4; mean difference 1.1 [95% CI 0.9-1.4]; p < 0.001, respectively) and teres minor (1.3 ± 0.7 versus 0.6 ± 0.5; mean difference 0.7 [95% CI 0.4-1.0]; p < 0.001 and 1.6 ± 0.6 versus 0.6 ± 0.5; mean difference 1.0 [95% CI 0.7-1.2]; p < 0.001, respectively). There was greater imbalance in fatty infiltration between the posterior and anterior rotator cuff muscles for Type B2 (0.5 ± 0.3) and B3 (0.6 ± 0.5) glenoids than for Type A1 (0.1 ± 0.3) and A2 (0.1 ± 0.6) glenoids (p < 0.001). Only the infraspinatus's fatty infiltration was strongly correlated with glenoid version (r = 0.64; p < 0.001), while fatty infiltration of the other muscles only correlated weakly or moderately. After accounting for age and sex, fatty infiltration in the infraspinatus was associated with Type B2 (OR 66.1 [95% CI 7.6-577.9]; p < 0.001) and Type B3 glenoids (OR 59.5 [95% CI 5.4-661.3]; p < 0.001) compared with Type A glenoids. CONCLUSION: Compared with concentric wear, posteriorly worn glenoids had an imbalance in axial-plane rotator cuff fatty infiltration and an increased amount of fatty infiltration of the infraspinatus and teres minor compared with the subscapularis. These imbalances may contribute to the higher rates of failure after anatomic total shoulder arthroplasty in patients with posterior wear compared with those with concentric wear. Future research should be directed toward investigating the temporal relationship of these findings, as well as understanding the clinical outcomes for patients undergoing anatomic total shoulder arthroplasty who have posteriorly worn glenoids with a high degree of fatty infiltration of the posterior rotator cuff musculature. CLINICAL RELEVANCE: Providers should consider the increased likelihood of higher-grade fatty infiltration of the posterior rotator cuff in the setting of posteriorly worn glenoids, particularly when treating patients without using MRI. These patients have higher rates of failure postoperatively and may benefit from closer monitoring and altered postoperative rehabilitation protocols that target the posterior rotator cuff.

Clinical Y-view versus 3-dimensional assessments of intramuscular fat in patients with full-thickness rotator cuff tears.

RATIONALE AND OBJECTIVES: Recent evidence suggests an inhomogeneous distribution of intramuscular rotator cuff fat infiltration (FI) in a small sample of individuals with rotator cuff tears, yet clinically just a few slices at the scapular Y-view are used to evaluate FI in patients with rotator cuff tears. The purpose of this study was to determine if assessment of FI using the scapular Y-view is representative of the entire muscle in patients with full-thickness rotator cuff tears, and whether this varies by tear size. MATERIALS AND METHODS: Patients (N = 25) diagnosed with full-thickness rotator cuff tear and confirmed with magnetic resonance imaging (MRI) were included. Fat-water sequences were used to objectively quantify mean FI (%) in the entire 3D muscle and the mean from 3 slices at the Y-view. Mixed-model 2 × 2 ANOVAs were used to assess for differences between methods, and if results vary by tear-size. RESULTS: There were no statistically significant differences between mean amount of FI of the entire 3D muscle and mean Y-view in the supraspinatus or infraspinatus muscles (p > 0.05). Additionally, this did not differ across tear size groups (p > 0.05). CONCLUSION: Results of this study suggest FI assessed in the Y-view is not different (mean difference < 1.0%) from FI of the entire 3D muscle in patients with full-thickness rotator cuff tears. Therefore, the clinical utility of evaluating rotator cuff intramuscular fat infiltration with the Y-view is further supported in patients with full-thickness rotator cuff tears across tear sizes.

Differences in 30-day outcomes between inpatient and outpatient total elbow arthroplasty (TEA).

BACKGROUND: As the health care system in the United States shifts toward value-based care, there has been increased interest in performing total joint arthroplasty in the outpatient setting to optimize costs, outcomes, and patient satisfaction. Several studies have demonstrated success in performing ambulatory total knee and hip arthroplasty. The purpose of this study was to compare short-term outcomes and complications after total elbow arthroplasty (TEA) across the inpatient and outpatient operative settings. METHODS: The American College of Surgeons National Quality Improvement Program database was queried to identify 575 patients undergoing primary TEA using the Current Procedural Terminology code 24363. Of this sample, 458 were inpatient and 117 were outpatient procedures. Propensity score matching using a 3:1 inpatient-to-outpatient ratio was performed to account for baseline differences in several variables-age, sex, body mass index class, American Society of Anesthesiologists class, and various comorbidities-between the inpatient and outpatient groups. After matching, the rates of various short-term outcomes and complications were compared between the inpatient and outpatient groups. RESULTS: Inpatient TEA was associated with a higher rate of complications relative to outpatient TEA, including non-home discharge (14.9% vs. 7.5%, P = .05), unplanned hospital readmission (7.4% vs. 0.9%, P = .01), surgical complications (7.6% vs. 2.6%, P = .04), and medical complications (3.6% vs. 0.0%, P = .04). CONCLUSION: Outpatient TEA has a lower short-term complication rate than inpatient TEA. Outpatient TEA should be considered for patients for whom such a discharge pathway is feasible. Future research should focus on risk stratification of patients and specific criteria for deciding when to pursue outpatient TEA.

Concussion Incidence and Impact on Player Performance in Major League Baseball Players Before and After a Standardized Concussion Protocol.

BACKGROUND: Sports-related concussions have garnered significant attention in recent years because of the negative effects they can have on a player's cognitive health and performance. In response to this growing concern, Major League Baseball (MLB) introduced a standardized concussion protocol during the 2011-2012 season. PURPOSE/HYPOTHESIS: The purpose of this study was to compare the reported incidence of concussions and the subsequent performance of MLB players before and after the introduction of the standardized concussion protocol. We hypothesized that the introduction of the standardized concussion protocol would not have an impact on player performance postconcussion. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Players who suffered a concussion between 2001 and 2018 were identified from the MLB transactions page. Incidence and player performance were compared before and after the introduction of the standardized concussion protocol. Player performance was evaluated using traditional data and sabermetric data, which are advanced statistics used in conjunction with standard statistics to better compare players and teams. Player averages were calculated and compared using paired t tests for 30 days before and after concussion, 1 year before and after concussion, and career before and after concussion. Averages were also compared before and after the institution of the standardized concussion protocol using independent-measures t tests. RESULTS: There were a total of 114 players who suffered 142 concussions, with 77% of those occurring after the introduction of the concussion protocol (32 before, 110 after). The average time missed because of concussion significantly decreased from 33.7 days (range, 10-122 days) to 18.9 days (range, 6-111 days) after the concussion protocol (P = .0005). There was no difference in player performance (including batting average, on-base percentage, and slugging for batters; earned run average, fielding-independent pitching, and walks plus hits per inning pitched for pitchers) after concussion at any time point (30 days, 1 year, or career) when comparing these statistics before versus after the MLB concussion protocol. However, batter performance was significantly poorer 1 year after concussion and over the remainder of the players' careers (P < .05). CONCLUSION: The number of reported concussions increased after the introduction of the MLB concussion protocol. However, players spent significantly less time on the disabled list without any adverse effect on player performance. Despite these changes, long-term batting performance was significantly poorer after concussion.

Evaluation of cerebral oxygen perfusion during shoulder arthroplasty performed in the semi-beach chair position.

BACKGROUND: The beach chair position is commonly used when performing shoulder arthroplasty. However, this position has been associated with hypotension, potentially leading to cerebral hypoperfusion, which may cause neurologic injury. In addition, shoulder arthroplasty cases are associated with longer operative times, posing a potentially greater risk of cerebral hypoperfusion. We aim to evaluate the risk of cerebral desaturation events (CDEs) during the course of total shoulder arthroplasty. METHODS: Twenty-six patients undergoing shoulder arthroplasties were monitored for changes in cerebral perfusion. Seven specific time-points during the procedure were labeled for comparison of events: baseline, beach chair, incision, humeral broaching, glenoid reaming, glenoid component implantation, and humeral component implantation. Cerebral oxygen perfusion was measured using near-infrared spectroscopy. A CDE was described as a decrease of oxygen saturation greater than 20%. RESULTS: Nineteeen of 25 subjects experienced a CDE. 42% of these patients experienced CDEs during semi-beach chair positioning. Patients experienced the largest oxygen saturation drop during semi-beach chair positioning. Transition from baseline to semi-beach chair was the only event to have a statistically significant decrease in cerebral perfusion (8%, P < .05). There was a statistically significant percentage change in mean oxygen saturation in the semi-beach chair interval (10%, P < .01) and the semi-beach chair to incision interval (7%, P < .01). CONCLUSIONS: Most patients experienced an intraoperative CDE, with greatest incidence during semi-beach chair positioning. The largest decline in cerebral oxygen saturation occurred during semi-beach chair positioning. Implant implantation was not associated with decrease in cerebral oximetry.

The Quality and Accuracy of Online Resources for Total and Reverse Shoulder Replacement.

Recent literature suggests that many online patient resources are poor in quality and lack important clinical information. The purpose of this study was to investigate the value of online resources available to patients considering shoulder arthroplasty. A total of 84 websites were discovered with the terms "total shoulder replacement" (TSR) and "reverse shoulder replacement" (RSR), they were reviewed and graded for quality and accuracy. Overall quality scores were low for TSR and RSR websites, 22.8/45 (95% confidence interval (CI): 19.9-25.6) and 24.2/45 (95% CI: 21.6-26.9), respectively. The authorship of a website significantly influenced the quality for both TSR (p = 0.013) and RSR (p = 0.048). When comparing search rank to quality scores, websites that appeared earlier demonstrated significantly higher quality scores, TSR (p = 0.017) and RSR (p = 0.018). Overall, most websites were accurate but provided incomplete information. Websites authored by professional societies have higher quality scores than websites authored by medical providers or commercial entities. (Journal of Surgical Orthopaedic Advances 28(4):290-294, 2019).

The Effect of an Arthroscopic Orthopaedic Procedure on a Professional Tennis Player's Career.

Orthopaedic injuries can significantly impact the careers of professional tennis players. It is currently unknown how professional tennis players fare after arthroscopic surgery. For the purpose of this study, players ranked in the Association of Tennis Professionals (ATP) and Women's Tennis Association (WTA) who underwent arthroscopic surgery of any joint between 1996 and 2016 were identified through a well-established, previously published protocol of injury reports and public archives. Performance statistics both before and after surgery, time to return (TTR) to play, and career length following surgery were collected for each player. Statistical analysis was performed with significance accepted at a probability value (p) of <0.05. A total of 55 (39 males and 16 females) players met the inclusion criteria (shoulder, n = 15; elbow, n = 15; wrist, n = 13; hip, n = 12). The average age of the players at the time of surgery was 25.8 (±4) years, and the average career length before surgery was 8.4 (±4) years. Tennis players who underwent arthroscopic shoulder surgery experienced a longer TTR to play (279 days, p <0.01), as well as a greater decline in their rankings, both in the first and second years postoperatively (p <0.01 and p = 0.01, respectively), compared to all other surgical cohorts. Players who underwent surgery on the elbow, wrist, and hip had no significant decline in the ranking by the second postoperative year. There were no significant differences between genders. This study represents the largest database of professional tennis players who have undergone arthroscopic surgery and may allow physicians to provide evidence-based recommendations about expectations after surgical treatment.

Reverse Total Shoulder Arthroplasty: Implant Design Considerations.

PURPOSE OF REVIEW: Our understanding of the reverse total shoulder arthroplasty (RTSA) has grown exponentially since Grammont first introduced his design in 1985. There are a multitude of implant-related variables to consider when performing RTSA. The purpose of this article is to provide a review of these design considerations. RECENT FINDINGS: Current literature demonstrates that the traditional Grammont prosthesis has over 90% survivorship at 10 years. Despite these promising results, there have been concerns raised over the significant rate of scapular notching observed. As a result, the traditional RTSA design has been modified to minimize this complication and maximize impingement-free motion. Modern RTSA designs with a cementless, curved, short-stemmed eccentric onlay humeral component combined with a large, lateralized glenosphere placed in 10° of inferior tilt with > 3.5 mm of inferior overhang have been found to provide excellent results. However, all implant design features must be considered on a case-by-case basis to optimize outcome for each patient. Humeral and glenoid implant design variables have evolved as the biomechanics of RTSA have been further elucidated. Consideration of these variables allows the surgeon to maximize joint efficiency, improve impingement-free range of motion, decrease the risk of scapular notching, preserve bone stock, and minimize the risk of instability.

Advanced Baseball Metrics Indicate Significant Decline in MLB Pitcher Value After Tommy John Surgery.

There are conflicting reports regarding the efficacy of Major League Baseball (MLB) pitchers following medial ulnar collateral ligament reconstruction (UCLR). As advanced baseball metrics have revolutionized the way general managers define pitchers' value, the authors believe that these should be used to measure clinical outcomes after UCLR. All MLB pitchers who underwent UCLR from April 1, 1991, through July 1, 2016, were compiled (N=253). Pitcher demographics and statistics were collected for up to 3 full seasons preceding and following surgery. Data for pitching controls (all MLB [AMLB] pitchers) were also collected (N=14,756). Prior to surgery, pitchers with UCLR were significantly better than the AMLB pitchers in nearly all advanced value-based statistics: higher wins above replacement (WAR; 0.93 vs 0.78; 95% confidence interval [CI], 0.80-1.06), lower fielding independent pitching (FIP; 4.23 vs 4.51; 95% CI, 4.12-4.34), lower expected fielding independent pitching (xFIP; 4.17 vs 4.38; 95% CI, 4.06-4.28), higher win probability added (WPA; 0.21 vs 0.05; 95% CI, 0.1-0.32), and higher leverage index (pLI; 1.03 vs 0.96; 95% CI, 0.99-1.06). Pitchers who returned to play after UCLR demonstrated significantly lower value with worse WAR, FIP, WPA, and pLI (P<.05). Conversely, after excluding pitchers who failed to achieve a sustained return to play of greater than 1 year, there were no significant decreases in value after surgery. The authors conclude that, prior to injury, pitchers who have UCLR are more valuable than average MLB pitchers. However, UCLR pitchers perform worse when compared with their presurgical values. This may be affected by players not being able to continue their careers for more than 1 year. [Orthopedics. 2019; 42(6):349-354.].

Editorial Commentary: Already "Stealth" Organism Propionibacterium acnes Goes Covert by Changing Its Name to Cutibacterium acnes: Shoulder Bacterial Contamination.

Propionibacterium acnes, now Cutibacterium acnes, is found on skin and subcutaneous tissue and is thus hard to eradicate. Infection can result in shoulder pain but be indolent and hard to diagnose; in addition, the organism is difficult to identify requiring long-hold cultures. Despite skin preparation, and second preparation before conversion of arthroscopy to mini-open surgery, we do not yet have a way to effectively eradicate C acnes from deeper dermal layers.

Development of 3D method to assess intramuscular spatial distribution of fat infiltration in patients with rotator cuff tear: reliability and concurrent validity.

BACKGROUND: Intramuscular fat infiltration is a critical factor in surgical decision-making and is the most important factor used to prognosticate surgical repair outcomes in patients with rotator cuff tears. Quantitative 3D assessment of total rotator cuff fat infiltration in patients with rotator cuff tears has been realized. However, a reproducible method to evaluate 3D spatial distribution of rotator cuff intramuscular fat has not been established. The objective of this study was to establish the reproducibility, change detectable beyond error, and concurrent validity of a semi-automated method to evaluate the 3D spatial distribution of fat infiltration and muscle volume in patients with rotator cuff tears. METHODS: Thirteen consecutive patients diagnosed with symptomatic rotator cuff pathology and 3.0 T MRI confirmation at a single center were included. Fat-water imaging was used to quantify 3D intramuscular fat (%fat) in sagittal oblique sequences and intramuscular spatial distribution with the semi-automated technique. Each rotator cuff muscle was manually segmented yielding %fat in four axial intramuscular quartile-regions (superior-inferior; Q1-4) and three sagittal (medial/ intermediate/ lateral) regions. Reliability and concurrent validity of %fat and whole muscle volume were calculated with intraclass correlation coefficients (ICC). RESULTS: Intra-rater reliability for intramuscular sagittal divisions (ICC = 0.93-0.99) and axial divisions (ICC = 0.78-0.99) was good/excellent. Inter-rater reliability for %fat (ICC = 0.82-0.99) and volume (ICC = 0.92-0.99) was good/excellent. Concurrent validity with commercialized software showed good/excellent agreement (ICC = 0.66-0.99). CONCLUSIONS: A new semi-automated method to assess 3-dimensional intramuscular distribution of fat infiltration in patients with rotator cuff tears using advanced MR imaging demonstrates high intra and inter-rater reliability and good concurrent validity. Minimal detectable change thresholds established facilitate clinical interpretation for future clinical application of this technique to assess change and treatment efficacy in patients with rotator cuff tears.

Influence of Pitching Release Location on Ulnar Collateral Ligament Reconstruction Risk Among Major League Baseball Pitchers.

BACKGROUND: Medial ulnar collateral ligament (UCL) reconstruction is a common procedure performed among Major League Baseball (MLB) pitchers. The etiology of UCL injury is complex and is not entirely understood. HYPOTHESIS: To better understand risk factors for requiring UCL reconstruction, we hypothesized that pitchers who eventually undergo the procedure will exhibit different throwing mechanics as measured by pitch-tracking data points, such as velocity and release location. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Pitch-tracking and demographic data were gathered for 140 MLB pitchers who had undergone UCL reconstruction between the 2010 and 2017 seasons. Pitch type, release location, and velocity were compared between the surgical cohort and a matched-control cohort. RESULTS: When compared with controls, the mean pitch release location for pitchers who required UCL reconstruction was 12.2 cm more lateral in the year immediately preceding surgery (P = .001). Furthermore, within the surgical cohort, the horizontal release location was 3.4 cm more lateral immediately preceding surgery compared with 2 years earlier (P = .036). Binary logistic regression indicated an odds ratio of 0.51, suggesting a roughly 5% increased odds of UCL reconstruction for every 10 cm of increased lateral release location (P = .048). Both the surgical and the control cohorts threw similar rates of fastballs and had similar mean pitch velocity and fastball velocity. Control pitchers displayed a significant decrease over time in mean pitch velocity (P = .005) and mean fastball velocity, while pitchers in the UCL reconstruction cohort did not (P = .012). CONCLUSION: Pitch tracking indicates that the mean release point is more lateral in pitchers preceding UCL reconstruction as compared with controls, suggesting that a more lateral pitch release location is an independent risk factor for UCL injury and reconstruction.

Optimizing methods to quantify intramuscular fat in rotator cuff tears with normalization.

OBJECTIVE: To determine which normalization method may best account for confounding individual factors, such as age or BMI, when quantifying fat infiltration on MRI in patients with rotator cuff tears, the effects of normalization using three different muscles (teres major; triceps brachii; teres minor) were compared. METHODS: Thirty-seven consecutive patients diagnosed with rotator cuff pathology were included. MRI fat-water sequences were used to quantify rotator cuff intramuscular fat (%fat). Three reference muscles (teres major, triceps, teres minor) were used to derive normalized %fat. Relationships between intramuscular %fat and tear size, age, and BMI in each rotator cuff muscle, before and after normalization, were compared with Fisher transformations (α = 0.05). RESULTS: Normalization with teres major ameliorated confounding relationships of age and BMI on rotator cuff %fat. In contrast, normalization with triceps maintained the confounding relationships between %fat and age in supraspinatus (p = 0.03) and infraspinatus/teres minor (p = 0.028). Normalization with teres minor maintained the confounding relationship between %fat and BMI in subscapularis (p = 0.039). Normalization with teres major best-maintained relationships between tear size and infraspinatus/teres minor %fat (p = 0.021). In contrast, normalization with triceps or teres minor eliminated all significant relationships with tear size. CONCLUSIONS: Results of this pilot study suggest normalization to teres major using MRI-based %fat quantification methods can effectively control for individual factors, such as BMI or age, and may have utility in evaluating and monitoring rotator cuff fat infiltration attributed specifically to a tendon tear.

Risk factors for admission after shoulder arthroscopy.

BACKGROUND: Shoulder arthroscopy is a common orthopedic procedure typically performed on an outpatient basis. Occasionally, patients require an unplanned hospital admission. An understanding of the incidence and risk factors for admission after shoulder arthroscopy may assist surgeons in determining which patients may be susceptible to unplanned admission after surgery. METHODS: All consecutive shoulder arthroscopy procedures performed during a 10-year period were reviewed. A 2:1 control-case matching technique was used. Univariate analysis was performed to identify differences between patients admitted after surgery and the control group. Multivariate analysis was performed to identify variables associated with admission. RESULTS: There were 5598 arthroscopic shoulder procedures performed, with 233 patients (4.2%) requiring admission. The most common reason for admission was respiratory monitoring. Risk factors for admission by multivariate analysis were chronic obstructive pulmonary disease (odds ratio [OR], 2.73; 95% confidence interval [CI], 1.51-4.95), diabetes (OR, 2.11; 95% CI, 1.28-3.48), obstructive sleep apnea (OR, 1.90; 95% CI, 1.13-3.21), age (OR, 1.02; 95% CI, 1.01-1.04), body mass index (OR, 1.04; 95% CI, 1.01-1.07), and operative time (OR, 1.01; 95% CI, 1.00-1.01). Regional with monitored anesthesia care decreased risk compared with general anesthesia and regional with general anesthesia (OR, 0.44; 95% CI, 0.30-0.63). CONCLUSION: Chronic obstructive pulmonary disease, obstructive sleep apnea, diabetes, increasing age, increasing body mas index, and increasing operative time were all risk factors for admission after shoulder arthroscopy. The absence of general anesthesia was found to decrease the risk of admission.

Late inception of a resiliently oxygenated upper ocean.

Rising oceanic and atmospheric oxygen levels through time have been crucial to enhanced habitability of surface Earth environments. Few redox proxies can track secular variations in dissolved oxygen concentrations around threshold levels for metazoan survival in the upper ocean. We present an extensive compilation of iodine-to-calcium ratios (I/Ca) in marine carbonates. Our record supports a major rise in the partial pressure of oxygen in the atmosphere at ~400 million years (Ma) ago and reveals a step change in the oxygenation of the upper ocean to relatively sustainable near-modern conditions at ~200 Ma ago. An Earth system model demonstrates that a shift in organic matter remineralization to greater depths, which may have been due to increasing size and biomineralization of eukaryotic plankton, likely drove the I/Ca signals at ~200 Ma ago.

Phanerozoic pO2 and the early evolution of terrestrial animals.

Concurrent gaps in the Late Devonian/Mississippian fossil records of insects and tetrapods (i.e. Romer's Gap) have been attributed to physiological suppression by low atmospheric pO2 Here, updated stable isotope inputs inform a reconstruction of Phanerozoic oxygen levels that contradicts the low oxygen hypothesis (and contradicts the purported role of oxygen in the evolution of gigantic insects during the late Palaeozoic), but reconciles isotope-based calculations with other proxies, like charcoal. Furthermore, statistical analysis demonstrates that the gap between the first Devonian insect and earliest diverse insect assemblages of the Pennsylvanian (Bashkirian Stage) requires no special explanation if insects were neither diverse nor abundant prior to the evolution of wings. Rather than tracking physiological constraint, the fossil record may accurately record the transformative evolutionary impact of insect flight.