No abstract

Purpose The purpose was to 1) determine whether standard clinical muscle fatty infiltration and atrophy assessment techniques using a single image slice for patients with a rotator cuff tear (RCT) are correlated with three-dimensional measures in older individuals (60+ years), and 2) determine whether age-associated changes to muscle morphology and strength are compounded by a RCT. Methods Twenty older subjects were studied, 10 with a RCT of the supraspinatus (5M/5F) and 10 matched controls. Clinical imaging assessments (Goutallier, Fuchs scores; cross-sectional area ratio) were made for RCT subjects. Three-dimensional measurements of rotator cuff muscle and fat tissues were made for all subjects using MRI. Isometric joint moment was measured at the shoulder. Results There were no significant associations between single-image assessments and three-dimensional measurements of fatty infiltration for supraspinatus and infraspinatus. Compared to controls, RCT subjects had significantly increased fatty infiltration percentages for each rotator cuff muscle (all p≤0.023), reduced whole muscle volume for supraspinatus, infraspinatus, and subscapularis (all p≤0.038), and reduced fat-free muscle volume for supraspinatus, infraspinatus, and subscapularis (all p≤0.027). Only teres minor (p=0.017) fatty infiltration volume was significantly greater for RCT subjects. Adduction, flexion, and external rotation strength (all p≤0.021) were significantly reduced for RCT subjects, and muscle volume was a significant predictor of strength for all comparisons. Conclusions Clinical scores using a single image slice do not represent three-dimensional muscle measurements. Efficient methods are needed to more effectively capture three-dimensional information for clinical applications. RCT subjects had increased fatty infiltration percentages likely driven by muscle atrophy rather than increased fat volume. Muscle volume’s significant association with strength production suggests that treatments to preserve muscle volume should be pursued for older RCT patients. Level of Evidence Level II, diagnostic study, with development of diagnostic criteria on the basis of consecutive patients with universally applied reference “gold” standard.

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.

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

No abstract