Non-Operative Shoulder Dysfunction in the United States Military

ABSTRACT Introduction Recent epidemiological evidence shows that shoulder and upper-arm complaints impose a substantial burden on the armed forces of the United States and create significant challenges for all components of the physical fitness domain of total force fitness. Clinicians, epidemiologists, and health-services researchers interested in shoulder and upper-arm injuries and their functional limitations rarely have objective, validated criteria for rigorously evaluating diagnostic practices, prescribed treatments, or the outcomes of alternative approaches. We sought to establish and quantify patient volume, types of care, and costs within the Military Health System (MHS) in assessing and managing active duty members with nonoperative shoulder and upper-arm dysfunction. Materials and Methods We performed a retrospective cohort study using data from the MHS Data Repository and MHS MART (M2) from fiscal year 2014 to identify active duty individuals with a diagnosis of shoulder and upper-arm injury or impairment defined by one of the International Classification of Disease Ninth Edition diagnosis codes that were selected to reflect nonoperative conditions such as fractures or infections. Statistical analyses include descriptive statistics on patient demographics and clinical visits, such as the range and frequency of diagnoses, number and types of appointments, and clinical procedure information following the diagnosis. We also examined treatment costs related to shoulder dysfunction and calculated the total cost to include medications, radiological, procedural, and laboratory test costs for all shoulder dysfunction visits in 2014 and the average cost for each visit. We further examined the category of each medication prescribed. Results A total of 55,643 individuals met study criteria and accrued 193,455 shoulder-dysfunction-related clinical visits in fiscal year 2014. This cohort represents approximately 4.8% of the 1,155,183 active duty service members assigned to the United States and its territories during FY 2014. Most patients were male (85.32%), younger (85.25% were under 40 years old), and Caucasian/White (71.12%). The most common diagnosis code was 719.41 (pain in joint, shoulder region; 42.48%). The majority of the patients 42,750 (76.8%) had four or fewer medical visits during the study period and 12,893 (23.2%) had more than four visits. A total of 4,733 patients (8.5%) underwent arthrocentesis aspiration or injection. The total cost for all visits was $65,066,767.89. The average and median cost for each visit were $336.34 (standard deviation was $1,493.87) and $163.11 (range was from 0 to $84,183.88), respectively. Three out of four patients (75.3%) underwent radiological examinations, and 74.2% of these individuals had more than one radiological examination. Medications were prescribed to 50,610 (91.0%) patients with the three most common being IBUPROFEN (12.21%), NAPROXEN (8.51%), and OXYCODONE-ACETAMINOPHEN (5.04%), respectively. Conclusions Nearly 1 in 20 active duty military service members presented for nonoperative care of shoulder and/or upper-arm dysfunction during FY2014. Further examinations of the etiology and potential impact of shoulder/upper-arm dysfunction on force readiness are clearly warranted, as are additional studies directed at identifying best practices for preventing injury-related dysfunction and determining best practices for the treatment of shoulder dysfunction to optimize service member fitness and force readiness.

Shoulder External Rotational Properties During Physical Examination Are Associated With Injury That Requires Surgery and Shoulder Joint Loading During Baseball Pitching

Background: Throwing arm injuries are common because of the demand on the shoulder. The shoulder is qualitatively checked regularly by team physicians. Excessive instability and joint loading in baseball pitching are risk factors for throwing arm injuries. Knowledge of shoulder flexibility, range of motion, and joint loading may provide new insights for treatments to reduce the likelihood of injury incidence. Purpose: To investigate the relationship among injuries, shoulder external rotational properties, and shoulder joint loading in baseball pitchers. Study Design: Descriptive laboratory study. Methods: Pitching kinetics, shoulder rotational tests, and self-reported injury questionnaires were used to study 177 collegiate baseball pitchers. Pitching motion data were collected at 240 Hz using a motion capture system. A custom program calculated the shoulder joint loading. The shoulder rotational test quantitatively records shoulder range of motion and flexibility using a custom-made wireless device. Self-reported injury questionnaires were filled out during tests and yearly follow-ups. The total length of the study was 5 years. Analysis of variance, chi-square, and regression tests were performed to compare differences among groups and detect correlations with surgery and shoulder joint loadings. Results: There were significant differences in shoulder flexibility among surgery groups. Shoulder external rotational properties during physical examination were significantly associated with shoulder joint loading in baseball pitching. High shoulder external rotation was associated with 14% to 36% lower shoulder posterior force and adduction, internal rotation, and horizontal adduction torque ( P < .05). High shoulder flexibility was associated with 13% higher anterior force ( P < .05). High shoulder external rotation before external rotation torque was applied was associated with 13% to 33% lower shoulder inferior force and adduction, internal rotation, and horizontal adduction torque ( P < .05). There were no significant differences in shoulder joint loading among the surgery groups. Conclusion: Shoulder injuries that require surgery were associated with shoulder external rotation flexibility. High shoulder external rotation may be advantageous because it lowers the force and torque on the shoulder joint. Clinical Relevance: The ability to understand shoulder external rotational properties, joint loading, and injury during baseball pitching helps further our understanding of injury mechanisms. The shoulder rotational test should be used as a screening tool to identify players at risk.

Starting pitchers demonstrate a greater hazard of arm injury compared to relief pitchers

Context: It is currently unclear how different pitching roles affect arm injury risk in professional pitchers. Objective: 1) Investigate the differences in arm injury hazard between professional baseball starting and relief pitchers; 2) Separately investigate elbow and shoulder injury hazard between professional baseball starting and relief pitchers. Study Design: Prospective cohort Setting: Minor League Baseball (MiLB) from 2013–2019 Patients or Other Participants: Pitchers Main Outcome Measures: Pitchers were followed for the entire MiLB season and athletic exposures (AE's) and injuries were recorded. Risk ratios and risk difference were calculated between starting and relieving MiLB pitchers. A cox survival analysis was then performed in relation to time to arm injury between starting and relieving MiLB pitchers. Subgroup analyses were performed for elbow and shoulder. Results: 297 pitchers were included with a total of 85,270 player days recorded. Arm injury incidence was 11.4 arm injuries per 10,000 AE's. Starting pitchers demonstrated greater risk ratio (1.2 (95% CI: 1.1–1.3)) and risk difference (13.6 (95% CI: 5.6–21.6)) and hazard of arm injury (2.4 (95% CI: 1.5–4.0)) compared to relief pitchers. No differences were observed for hazard of elbow injury between starting and relief pitchers (1.9 (95% CI: 0.8–4.2)). Starting pitchers demonstrated greater hazard of shoulder injury compared to relief pitchers (3.8 (95% CI: 2.0–7.1)). Conclusions: Starting pitchers demonstrated almost two and a half times greater hazard of arm injury compared to relief pitchers. Subgroup analyses demonstrated that starters exhibited greater hazard of shoulder injury compared to relievers; but, no differences were observed for hazard of elbow injury. However, due to the wide confidence intervals, these subgroup analyses should be interpreted with caution. Clinicians may need to consider cumulative exposure and fatigue and how these factors relate to different pitching roles when assessing pitching arm injury risk.

A small number of daily pitches induces shoulder and elbow injuries among high school baseball pitchers: a prospective study

Baseball players frequently injure their shoulders and elbows. Preseason risk factors for such injuries have been relatively well studied, but in-season risk factors are less known, and the relationship between the number of pitches and the incidence of such injuries in baseball pitchers of any level is unclear. Identifying the risk factors related to the number of daily pitches is particularly important to prevent baseball-related arm injuries among young pitchers. Thus, we prospectively investigated the relationship between the number of daily full-power pitches in high school baseball pitchers and the incidence of shoulder and elbow injuries. We observed that a small number of daily full-power pitches, < 30 pitches per day, in high school baseball pitchers, significantly increased the risk of shoulder and elbow injuries: these players had a 2.3-times greater risk of injuries and a 45-day earlier occurrence of injuries than those pitching ≥ 30 pitches per day. Although unexpected, this was plausible as continuous daily pitching is required to maintain physical condition in growing and maturing high school pitchers. These findings may form the basis for establishing guidelines regarding the appropriate number of daily pitches required to prevent shoulder and elbow injuries in high school baseball pitchers.

Sport Specialization and Increased Injury Frequency in Youth Baseball Players: A Prospective Study

Context Sport specialization is thought to be a primary contributor to the throwing-related injury risk in youth baseball players. Objective To (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. Design Cohort study. Setting Greenville, South Carolina, youth baseball programs and tournaments. Patients or Other Participants A 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. Results Youth 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). Conclusions Sport 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.

Risk Factors for Baseball-Related Arm Injuries: A Systematic Review

Background: Contributing factors for arm injuries among baseball players have been described. However, no review has systematically identified risk factors with findings from prospective cohort studies. Purpose: To systematically review prospective cohort studies that investigated risk factors for arm injury among baseball players. Study Design: Systematic review; Level of evidence, 3. Methods: Electronic databases were searched for relevant English-language studies. Titles, abstracts, and full-text articles were screened by 2 blinded reviewers to identify only prospective cohort studies and randomized controlled trials. Two independent investigators screened each article for appropriate criteria. Results: Fourteen prospective articles were selected for this review. Youth, high school, and professional baseball players (N = 2426) were pooled, and 43 risk factors were assessed in relation to general arm, shoulder, and elbow injuries. All studies evaluated players for at least 1 season. Deficits in preseason shoulder range of motion and strength were significant risk factors for general arm or shoulder injury among high school and professional players. Elbow and shoulder varus torque at peak external shoulder rotation during pitching, high pitch velocity, and shoulder rotational and flexion deficits were risk factors for elbow injuries among professional pitchers. Pitching >100 innings in 1 year, being aged 9 to 11 years, being a pitcher or catcher, training >16 hours per week, and having a history of elbow pain were significant risk factors for elbow injury among youth players. Conclusion: History of elbow pain and age had a high risk of associated elbow injury among youth players. Training or pitching load also increased elbow injury risk for youth athletes. Loss of shoulder range of motion appears to increase risk for elbow injury among professional athletes. Single time-point data collections per season, studies with the same sample population, and studies with self-reported injury and risk factor data may limit the interpretation of these findings. Health care professionals should use caution when assessing injury risk during evaluation and making decisions about the training workload and playing time of baseball players.