Shoulder Range of Motion Measurements and Baseball Elbow Injuries: Ambiguity in Scientific Models, Approach, and Execution is Hurting Overhead Athlete Health
Abstract Elbow injuries are a significant and increasing issue in baseball. Elbow injuries account for 16% of all injuries sustained at the professional level and collegiate level. Because of the continued rise in injury rates, loss of performance value, and medical burden, sports medicine clinicians have attempted to research the causes underlying this injury epidemic in an attempt to help mitigate baseball elbow injuries. Shoulder range of motion (ROM) is the most researched clinical metric related to elbow injuries in baseball and has the greatest consensus as a viable prognostic factor specifically for medial elbow injury. Shoulder ROM is easy to measure, can be modified through stretching and manual therapy interventions, and can be easily assessed during preseason screening throughout all baseball levels. Despite a large number of studies and the widespread use of shoulder ROM in injury risk screening, current findings are unclear as to whether there is a true cause‐effect relation with baseball elbow injuries. We argue that the conflicting findings revolving around the value of shoulder ROM measurements associated with baseball elbow injuries are the result of 4 gaps in the research approaches implemented to date: ambiguous research questions, mixed study populations, statistical models used, and shoulder ROM methodology. Specifically, there is a mismatch of methods, statistical models, and conclusions such as (1) investigating the association (i.e., correlation) between shoulder ROM measurements and injury and (2) investigating the cause‐effect relation of shoulder ROM to baseball injuries. The purpose of this article is to detail the required scientific steps to evaluate whether preseason shoulder ROM is a potential causal factor for pitching elbow injury. We also provide recommendations to allow for future causal inferences to be made between shoulder ROM and elbow injury. This information will ultimately assist in informing clinical models of care and decision making for baseball throwers.
Normalized Isometric Shoulder Strength as a Predictor of Ball Velocity in Youth Baseball Players
BACKGROUND Despite increased awareness of factors related to athletic performance and injury prevention, youth and adolescent baseball players continue to report injuries at alarming rates. Upper extremity muscle strength is an integral part of physical assessment and injury prevention in baseball players, however minimal data exists in youth populations. Changes in anthropometric measures, inherent in physically developing athletes, have been shown to impact strength measures, however normalization methodology is rarely reported. PURPOSE The purposes of this study were to 1) compare the measurement properties of five potential methods for normalizing isometric shoulder strength in a cohort of 9-12 year old male baseball players and 2) examine the relationship between normalized isometric shoulder strength and ball velocity in a cohort of 9-12 year old male baseball players. STUDY DESIGN Prospective cohort study (n=159) METHODS Baseline and follow up height, weight and bilateral ulnar length measurements were assessed followed by isometric strength in both the dominant and non-dominant shoulders. Strength measures included scapular plane abduction (scaption), external rotation (ER) at 0°, ER and internal rotation (IR) at 90°. Ball velocity was assessed as a measure of throwing performance. Intraclass correlation coefficients (ICC2,1), standard errors of measurement (SEM) and minimal detectable change (MDC95) were calculated for all strength measures. Repeated measures ANOVA were conducted comparing changes in normalized strength using five separate anthropometric measures: weight, height, body mass index, ulnar length and % of non-dominant shoulder strength. Linear regression models were used to examine the relationships between normalized isometric shoulder strength and ball velocity. Statistical significance was set a priori at α=0.05. RESULTS Shoulder strength normalized using ulnar length was the only method that demonstrated excellent reliability (ICC2,1 0.98-0.99) and detected significant changes between strength in each of the four measures tested (SEM 0.39-0.69 Nm). Modest but significant correlations were observed between scaption and ball velocity (r2 = 0.27, p < 0.001) and ER at 0° and ball velocity (r2 = 0.23, p < 0.001). CONCLUSION Ulnar length was the most stable and reliable normalization method for assessing isometric shoulder strength in youth baseball players. In addition, normalized scaption strength was the most significant predictor of ball velocity, followed by ER at 0° strength in this population. LEVEL OF EVIDENCE Level 2b (etiology)
Sport Specialization and Increased Injury Frequency in Youth Baseball Players: A Prospective Study
ContextSport specialization is thought to be a primary contributor to the throwing-related injury risk in youth baseball players.ObjectiveTo (1) establish arm-injury incidence in a cohort of male youth (9–12 years old) baseball players and (2) examine sport specialization and the frequency of arm injuries in the same cohort.DesignCohort study.SettingGreenville, South Carolina, youth baseball programs and tournaments.Patients or Other ParticipantsA total of 159 asymptomatic youth baseball players (age = 11.1 ± 1.1 years) were physically assessed and then were prospectively followed for 6.7 ± 1.5 months.Main Outcome Measure(s)Athlete demographics and playing and injury histories were initially recorded. Athlete-exposures and presence of arm injury were prospectively tracked. All injuries were physically confirmed by a licensed physical therapist.ResultsYouth players demonstrated an arm-injury incidence rate of 2.22 per 1000 athlete-exposures. Parents and players underestimated sport-specialization status based on the standard research definition (self versus research based: 31% versus 83%, respectively; P = .001). The frequency of arm injuries was higher in specialized players (100%) than in nonspecialized players (80%, P = .03) but did not differ between pitchers and position players (13.2% each, P = 1.00).ConclusionsSport specialization was associated with throwing-related arm injuries in a small cohort of youth baseball players. It is concerning that 57.9% of parents and specialized players were unaware of the athletes' status. Larger studies with longer follow-up periods are needed to further evaluate injury-risk profiles in physically developing youth populations.
Return to Sport as an Outcome Measure for Shoulder Instability: Surprising Findings in Nonoperative Management in a High School Athlete Population
Background: Young age and contact sports have been postulated as risk factors for anterior shoulder instability. Management after shoulder instability is controversial, with studies suggesting that nonoperative management increases the risk of recurrence. Several studies examined return to play after an in-season instability episode, and few followed these patients to determine if they were able to successfully compete in a subsequent season. No study has evaluated this question in a high school athlete population. Purpose: To compare the likelihood of return to scholastic sport and complete the next full season without an additional time-loss injury among athletes with anterior shoulder instability in terms of treatment, instability type, and sport classification. Study Design: Cohort study; Level of evidence, 2 Methods: Athletes were included in this study as identified by a scholastic athletic trainer as experiencing a traumatic time-loss anterior shoulder instability injury related to school-sponsored participation. The cohort was predominantly male (n = 108, 84%) and consisted mostly of contact athletes (n = 101, 78%). All athletes had dislocation or subluxation diagnosed by a board-certified physician who determined the athlete’s course of care (nonoperative vs operative). Successful treatment was defined as completion of care and return to the athlete’s index sport, with full participation for the following season. Chi-square and relative risk analyses were completed to compare success of treatment (nonoperative vs operative care) and instability type. Separate logistic regressions were used to compare the effect of sex and sport classification on the athletes’ ability to return to sport. Statistical significance was set a priori as α = .05. Results: Scholastic athletes (N = 129) received nonoperative (n = 97) or operative (n = 32) care. Nonoperatively treated (85%) and operatively treated (72%) athletes successfully returned to the same sport without injury for at least 1 full season ( P = .11). Players sustaining a dislocation were significantly more likely to fail to return when compared with those sustaining a subluxation (26% vs 89%, P = .013). Sex ( P = .85) and sport classification ( P = .74) did not influence the athlete’s ability to return to sport, regardless of treatment type. Conclusion: A high percentage of athletes with shoulder instability achieved successful return to sport without missing any additional time for shoulder injury. Those with subluxations were at almost 3 times the odds of a successful return compared with those sustaining a dislocation.
Comparison of Surgeon Performance of Rotator Cuff Repair
Background: Movement toward a value-based health-care system necessitates the development of performance measures to compare physicians, hospitals, and health-care systems. Patient-reported outcomes (PROs) are a potential metric. However, valid use of PROs hinges on the ability to risk-adjust for baseline patient differences across a surgeon’s panel of patients. The purpose of this study was to propose an approach for baseline risk adjustment and evaluate the importance of risk adjustment when comparing surgeons’ performance of rotator cuff repair. Methods: Patients (n = 995) treated with arthroscopic rotator cuff repair by 34 surgeons from 2010 to 2017 were identified from a large sports medicine clinical data registry. A linear regression model was used to adjust for baseline PROs, patient demographics, and clinical characteristics to predict American Shoulder and Elbow Surgeons (ASES) change scores for each surgeon. A risk-adjusted performance measure was calculated as the difference between the average unadjusted ASES change scores and the risk-adjusted predicted ASES change scores across all patients treated by a surgeon. Results: The differences between unadjusted and risk-adjusted performance scores varied widely across surgeons (range, −13.8 to 10.3 ASES points). Use of the risk-adjusted performance scores resulted in a dramatic change in the relative ranking of surgeons, compared with the ranking based on the observed ASES change scores, with 31 of the 34 surgeons’ rank changing following risk adjustment. On average, the observed ASES scores improved from 49.5 ± 17.5 at baseline to 78.0 ± 22.5 at 6 months across all surgeons. In the risk-adjustment model (R 2 = 0.44), male sex, Workers’ Compensation status, higher scores on the Veterans RAND 12-item Health Survey (VR-12), lower baseline ASES scores, fair and poor tendon quality, and night pain all had a significant effect on the predicted ASES change scores (p < 0.05). Conclusions: Our results show wide variation of nearly 25 points in the risk-adjusted 6-month ASES performance difference from the highest to the lowest-performing surgeons. Additionally, 91% of surgeons’ rank changed following risk adjustment. This suggests that performance measurement that does not account for baseline patient characteristics would likely result in incorrect conclusions about a surgeon’s relative performance based on PROs. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.
Validity and Responsiveness of the Single Alpha-numeric Evaluation for Shoulder Patients
Background: There is an ever-increasing demand for widespread implementation of patient-reported outcomes. However, adoption is slow owing to limitations in clinical infrastructure and resources within busy orthopaedic practices. Prior studies showed the single alpha-numeric evaluation (SANE) score to correlate at a single point in time with the American Shoulder and Elbow Surgeons (ASES) score. However, no study has validated the SANE in terms of test-retest reliability, responsiveness, or clinical utility. Purpose: To validate SANE with the ASES across a sample of patients with common orthopaedic shoulder diagnoses. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Patients undergoing rotator cuff repair (n = 77), total shoulder replacement (n = 55), or physical therapy (n = 80) for signs and symptoms of subacromial impingement syndrome (n = 61) or adhesive capsulitis (n = 19) were administered the SANE and ASES at baseline and again at their 3-month follow-up from initial care or surgery (N = 212, mean ± SD age = 52.6 ± 1.2 years, n = 145 women). Interclass correlation coefficient (ICC 2,1 ) and standard error of the measurement (SEm) were used to evaluate the test-retest reliability of the SANE and the validity between the SANE and ASES scores. Analysis of variance (treatment group × time) was used to evaluate the responsiveness to treatment, and a receiver operating characteristic curve was used to establish the minimal clinically important difference (MCID) for the SANE as compared with the ASES (α = .05). Floor and ceiling effects were evaluated as the percentage of patients who scored the highest or lowest score on each tool. Results: The SANE demonstrated good pretreatment reliability (ICC 2,1 = 0.84, SEM = 3.8), similar to the ASES (ICC 2,1 = 0.82, SEM = 3.4). The SANE also showed good agreement with the ASES before and after treatment across all treatment groups (rotator cuff repair, ICC 2,1 = 0.85, SEM = 3.4; total shoulder replacement, ICC 2,1 = 0.72, SEM = 5.2; physical therapy: ICC 2,1 = 0.82, SEM = 2.9). The SANE and ASES displayed similar responsiveness after treatment, with similar mean change and SD within each treatment group. The receiver operating characteristic curve revealed an area under the curve of 0.79 (SE, 0.62; P < .001) and a cutoff of 15% on the SANE, with a sensitivity of 85% to establish the MCID. Acceptable and similar floor and ceiling effects were observed for the ASES (4%) and SANE (9%). Conclusion: The study demonstrates that the SANE is valid for a range of common shoulder diagnoses to assess patient outcomes across operative and nonoperative treatment for shoulder complaints. The MCID of 15% is similar to that of the ASES (11%), suggesting that the SANE is a simple and efficient tool to assess treatment effects for shoulder disorders. Future studies are warranted to confirm these results and compare across other body parts and diagnoses.
Using Stress Ultrasonography to Understand the Risk of UCL Injury Among Professional Baseball Pitchers Based on Ligament Morphology and Dynamic Abnormalities
Background: Ulnar collateral ligament (UCL) injury of the elbow is a common and debilitating problem seen frequently among elite baseball pitchers. Ultrasound is a useful diagnostic tool in evaluating UCL injuries. Hypothesis: Evaluation with stress ultrasound of the elbow to measure the morphology of the UCL and the ulnohumeral joint space gapping is indicative of higher risk of UCL injury among professional baseball pitchers. Study Design: Cohort study; Level of evidence, 2. Methods: Ultrasound imaging was used to assess the medial joint laxity of the elbow of 70 asymptomatic professional baseball pitchers during spring training. Medial joint laxity and UCL morphology were assessed with OsiriX imaging software under 2 conditions—gravity valgus load and 5.5 lb of valgus load per a handheld dynamometer—with the shoulder in the maximal cocking position and the elbow in 90° of flexion. Two trials of resting position, elbow gapping, and UCL thickness were collected, measured, and averaged for data analysis. Intra- and interrater reliabilities were established and maintained, with intraclass correlation coefficients in the acceptable range for all measures (0.84-0.99). One-way analysis of variance was used to compare dominant variables between those pitchers who sustained a subsequent UCL injury and those who did not. A receiver operating curve was used to identify pitchers who, based on elbow gapping measures (by cut score), were at high risk versus low risk for UCL injury. Results: Players who went on to injure the UCL (n = 7) displayed a significantly wider opening under 5.5 lb of applied stress (6.5 ± 1.2 vs 5.3 ± 1.2 mm, P = .01) when compared with pitchers without UCL injury history (n = 63); they also presented a trend toward wider dominant arm resting joint opening (4.9 ± 1.2 vs 4.0 ± 1.1 mm, P = .07). Professional pitchers with valgus stress ulnohumeral joint gapping ≥5.6 mm (area underneath the curve, 0.77; P = .02) of the dominant arm were at a 6-times greater risk of sustaining a UCL tear requiring reconstruction within a season. Conclusion: Our data suggest that ultrasound evaluation of UCL morphology may be indicative of pitchers who are at risk of sustaining UCL injury and that it may improve player assessment.
Treatment for Rotator Cuff Tear Is Influenced by Demographics and Characteristics of the Area Where Patients Live
Background: Atraumatic rotator cuff tear is a common orthopaedic complaint for people >60 years of age. Lack of evidence or consensus on appropriate treatment for this type of injury creates the potential for substantial discretion in treatment decisions. To our knowledge, no study has assessed the implications of this discretion on treatment patterns across the United States. Methods: All Medicare beneficiaries in the United States with a new magnetic resonance imaging (MRI)-confirmed atraumatic rotator cuff tear were identified with use of 2010 to 2012 Medicare administrative data and were categorized according to initial treatment (surgery, physical therapy, or watchful waiting). Treatment was modeled as a function of the clinical and demographic characteristics of each patient. Variation in treatment rates across hospital referral regions and the presence of area treatment signatures, representing the extent that treatment rates varied across hospital referral regions after controlling for patient characteristics, were assessed. Correlations between measures of area treatment signatures and measures of physician access in hospital referral regions were examined. Results: Among patients who were identified as having a new, symptomatic, MRI-confirmed atraumatic rotator cuff tear (n = 32,203), 19.8% were managed with initial surgery; 41.3%, with initial physical therapy; and 38.8%, with watchful waiting. Patients who were older, had more comorbidity, or were female, of non-white race, or dual-eligible for Medicaid were less likely to receive surgery (p < 0.0001). Black, dual-eligible females had 0.42-times (95% confidence interval [CI], 0.34 to 0.50) lower odds of surgery and 2.36-times (95% CI, 2.02 to 2.70) greater odds of watchful waiting. Covariate-adjusted odds of surgery varied dramatically across hospital referral regions; unadjusted surgery and physical therapy rates varied from 0% to 73% and from 6% to 74%, respectively. On average, patients in high-surgery areas were 62% more likely to receive surgery than the average patient with identical measured characteristics, and patients in low-surgery areas were half as likely to receive surgery than the average comparable patient. The supply of orthopaedic surgeons and the supply of physical therapists were associated with greater use of initial surgery and physical therapy, respectively. Conclusions: Patient characteristics had a significant influence on treatment for atraumatic rotator cuff tear but did not explain the wide-ranging variation in treatment rates across areas. Local-area physician supply and specialty mix were correlated with treatment, independent of the patient’s measured characteristics.
Arthroscopic Superior Capsular Reconstruction in Males Provides Superior Outcomes to Reverse Total Shoulder or Debridement for Irreparable Rotator Cuff Tears
Objectives: Early results following arthroscopic superior capsular reconstruction(SCR) in patients with massive, irreparable rotator cuff tears are promising. However, no studies have compared patient reported outcomes between SCR or reverse total shoulder(rTSA) and rotator cuff debridement for these patients. Therefore, the purpose of this study was to compare 1-year outcomes between patients with massive irreparable rotator cuff tears who underwent a SCR, rTSA, or rotator cuff debridement with a concurrent biceps tenotomy or tenodesis. Methods: Patients(n=63) who underwent either SCR(n=21), rTSA(21), or cuff debridement(n=21) and biceps tenotomy or tenodesis for a massive, irreparable rotator cuff tear treated with a minimum 1-year follow up were retrospectively reviewed. Age, sex, BMI, smoking status, Charlson Index, Hamada classification, and ASES scores were recorded and compared using a multivariate ANOVA were used to compare between surgical approaches. A Chi Square analyses were used to compare sex distribution and the Charlson Deyo Index between groups (α=0.05). Results: Overall, patients across the 3 groups were not statistically different in age or follow up ASES score at minimum 14 month follow up ( P> 0.05). There was a significant interaction effect between surgery group and sex (P=0.02) on ASES score but not age ( P=0.08). Univariate F tests revealed that male patients who received an SCR displayed a 10-14% better outcome at follow up compared to other groups (Table 1) which exceeds the reported ASES score MCID. Conclusion: Our results show comparable results across surgical options for massive irreparable cuff tears with good patient reported outcomes. Male patients displayed clinically important greater ASES scores at 1 year follow up. Future studies should evaluate these preliminary results to assess if these preliminary results hold up at longer follow up times.
Preoperative Ultrasonography Is Unreliable in Predicting Hamstring Tendon Graft Diameter for ACL Reconstruction
Background: Hamstring autograft size <8 mm has been shown to be a predictor for failure after anterior cruciate ligament (ACL) reconstruction. The ability to predict graft size preoperatively is helpful in counseling patients about the possible need for graft augmentation. Purpose: To determine whether preoperative ultrasound (US) measurements of hamstring tendons can predict intraoperative graft diameter during ACL reconstruction. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Twenty patients undergoing unilateral isolated ACL reconstruction were prospectively enrolled in the study (10 males, 10 females; mean ± SD age, 22.8 ± 6.6 years; height, 175.1 ± 7.1 cm; weight, 81.4 ± 14.2 kg; body mass index, 26.5 ± 4.1 kg/m 2 ). Hamstrings were assessed by US, and double-looped semitendinosus-gracilis hamstring size was independently calculated with a freehand selection method on a nonmagnified US image by 2 orthopaedic surgeons. Intraoperative autograft size was determined with a standard graft-sizing tool. Intra- and interrater reliability was measured with intraclass correlation coefficients (ICCs) and standard error of the measure (SEM). A receiver operating characteristic curve was calculated to assess the ability of the US measurement to predict intraoperative measurements. Results: The mean autograft diameter by US was 8.9 ± 0.98 mm, while the mean intraoperative hamstring graft size was 8.1 ± 0.89 mm. There was excellent intrarater (ICC 2,1 = 0.95, SEM = 0.32 mm) and interrater (ICC 2,1 = 0.88, SEM = 0.55 mm) reliability for US measurements. Receiver operating characteristic analysis showed that US did not consistently quantify graft size. Graft size did not significantly correlate with height, weight, or body mass index in our sample ( P > .05). Conclusion: These results suggest that preoperative US imaging of the hamstring tendons is unreliable in predicting intraoperative graft diameter.