A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part II: strength.

CONTEXT: A database describing the range of normal rotator cuff strength values in uninjured high school pitchers has not been established. Chronologic factors that contribute to adaptations in strength also have not been established. OBJECTIVES: To establish a normative profile of rotator cuff strength in uninjured high school baseball pitchers and to determine whether bilateral differences in rotator cuff strength are normal findings in this age group. DESIGN: Cohort study. SETTING: Baseball playing field. PATIENTS OR OTHER PARTICIPANTS: A total of 165 uninjured male high school baseball pitchers (age = 16 ± 1 years, height=1.8±0.1 m, mass=76.8±10.1 kg, pitching experience =7±2 years). MAIN OUTCOME MEASURE(S): Isometric rotator cuff strength was measured bilaterally with a handheld dynamometer. We calculated side-to-side differences in strength (external rotation [ER], internal rotation [IR], and the ratio of ER:IR at 90° of abduction), differences in strength by age, and the influence of chronologic factors (participant age, years of pitching experience) on limb strength. RESULTS: Side-to-side differences in strength were found for ER, IR, and ER:IR ratio at 90° of abduction. Age at the time of testing was a significant but weak predictor of both ER strength (R(2)=0.032, P = .02) and the ER:IR ratio (R(2)=0.051 , P = .004) at 90° of abduction. CONCLUSIONS: We established a normative profile of rotator cuff strength for the uninjured high school baseball pitcher that might be used to assist clinicians and researchers in the interpretation of muscle strength performance in this population. These data further suggested that dominant-limb adaptations in rotator cuff strength are a normal finding in this age group and did not demonstrate that these adaptations were a consequence of the age at the time of testing or the number of years of pitching experience.

A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part I: motion.

CONTEXT: The magnitude of motion that is normal for the throwing shoulder in uninjured baseball pitchers has not been established. Chronologic factors contributing to adaptations in motion present in the thrower's shoulder also have not been established. OBJECTIVES: To develop a normative profile of glenohumeral rotation motion in uninjured high school baseball pitchers and to evaluate the effect of chronologic characteristics on the development of adaptations in shoulder rotation motion. DESIGN: Cohort study. SETTING: Baseball playing field. PATIENTS OR OTHER PARTICIPANTS: A total of 210 uninjured male high school baseball pitchers (age = 16 ± 1.1 years, height=1.8±0.1 m, mass=77.5±11.2 kg, pitching experience=6±2.3 years). INTERVENTION(S): Using standard goniometric techniques, we measured passive rotational glenohumeral range of motion bilaterally with participants in the supine position. MAIN OUTCOME MEASURE(S): Paired t tests were performed to identify differences in motion between limbs for the group. Analysis of variance and post hoc Tukey tests were conducted to identify differences in motion by age. Linear regressions were performed to determine the influence of chronologic factors on limb motion. RESULTS: Rotation motion characteristics for the population were established. We found no difference between sides for external rotation (ER) at 0° of abduction (t(209) = 0.658, P = .51), but we found side-to-side differences in ER (t(209) =-13.012,P < .001) and internal rotation (t(209) =15.304, P < .001) at 90° of abduction. Age at the time of testing was a significant negative predictor of ER motion for the dominant shoulder (R(2) = 0.019, P = .049) because less ER motion occurred at the dominant shoulder with advancing age. We found no differences in rotation motion in the dominant shoulder across ages (F(4,205) range, 0.451-1.730,P > .05). CONCLUSIONS: This range-of-motion profile might be used to assist with the interpretation of normal and atypical shoulder rotation motion in this population. Chronologic characteristics of athletes had no influence on range-of-motion adaptations in the thrower's shoulder.

Comparison of shoulder range of motion, strength, and playing time in uninjured high school baseball pitchers who reside in warm- and cold-weather climates.

BACKGROUND: There is an assumption that baseball athletes who reside in warm-weather climates experience larger magnitude adaptations in throwing shoulder motion and strength compared with their peers who reside in cold-weather climates. HYPOTHESES: (1) The warm-weather climate (WWC) group would exhibit more pronounced shoulder motion and strength adaptations than the cold-weather climate (CWC) group, and (2) the WWC group would participate in pitching activities for a greater proportion of the year than the CWC group, with the time spent pitching predicting throwing shoulder motion and strength in both groups. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: One hundred uninjured high school pitchers (50 each WWC, CWC) were recruited. Rotational shoulder motion and isometric strength were measured and participants reported the number of months per year they pitched. To identify differences between groups, t tests were performed; linear regression was used to determine the influence of pitching volume on shoulder motion and strength. RESULTS: The WWC group pitched more months per year than athletes from the CWC group, with the number of months spent pitching negatively related to internal rotation motion and external rotation strength. The WWC group exhibited greater shoulder range of motion in all planes compared with the CWC group, as well as significantly lower external rotation strength and external/internal rotation strength ratios. There was no difference in internal rotation strength between groups, nor a difference in the magnitude of side-to-side differences for strength or motion measures. CONCLUSION: Athletes who reside in cold- and warm-weather climates exhibit differences in throwing shoulder motion and strength, related in part to the number of months spent participating in pitching activities. The amount of time spent participating in pitching activities and the magnitude of range of motion and strength adaptations in athletes who reside in warm-weather climates may make these athletes more susceptible to throwing-related injuries.

The effects of shoulder laxity on upper extremity blood flow in professional baseball pitchers.

BACKGROUND: The repetitive overhand throwing can potentially cause physiologic or pathologic changes in musculoskeletal and vascular structures. The purpose of this study was to investigate the effects of throwing on upper extremity arterial blood flow before and after a controlled pitching session. The hypothesis is that pitchers with physical signs of shoulder laxity would demonstrate differential changes in upper extremity blood flow as compared to those without laxity. METHODS: Eighteen professional male pitchers underwent a detailed shoulder physical evaluation, followed by a wrist/brachial index (WBI) vascular exam and a vascular ultrasound examination before and after a controlled throwing session. RESULTS: Following a 50-pitch workout, the WBI was significantly lower (0.79-0.86) in pitchers with laxity on exam versus no laxity (P < .05). For all pitchers, the average arterial volume flow increased from 234 ml/min to 482 ml/min after 50 pitches. Pitchers without physical signs of laxity had an average arterial volume flow increase of 115%, while the pitchers with laxity signs increased 35%. CONCLUSION: This study demonstrated a statistically significant decrease in arterial blood flow in the laxity group compared to the nonlaxity throwers.

Clinical follow-up of professional baseball players undergoing ulnar collateral ligament reconstruction using the new Kerlan-Jobe Orthopaedic Clinic overhead athlete shoulder and elbow score (KJOC Score).

BACKGROUND: There are no validated outcome measures consistently used in the literature to report results of ulnar collateral ligament reconstruction in overhead athletes. HYPOTHESIS: The Kerlan-Jobe Orthopaedic Clinic Overhead Athlete Shoulder and Elbow score (KJOC score) will correlate with other validated scores for upper extremity assessment but will be more accurate in evaluating ulnar collateral ligament reconstruction outcomes in professional baseball players. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Fifty-five professional baseball players who underwent ulnar collateral ligament reconstruction were asked to complete the KJOC score, the Disabilities of the Arm, Shoulder and Hand (DASH) score, and the DASH sports module. Players were separated into 3 categories-(1) playing without pain, (2) playing with pain, and (3) not playing because of pain-and compared with 123 asymptomatic throwers. Pearson (parametric) and Spearman rank (nonparametric) correlations among the 3 systems were conducted to validate the KJOC score. Means across categories were compared using a Wilcoxon rank-sum test, and a threshold score separating categories 1 and 3 was determined using receiver operator characteristic discrimination analysis. RESULTS: Significant correlations were found between the KJOC score and the DASH (-.693, P < .0001), and the DASH sports module (-0.804, P < .0001). Only the KJOC score was able to discriminate between categories 2 and 3, as well as category 1 and the uninjured population. In addition, the KJOC score was the most sensitive and accurate method of discriminating category 1 from category 3, with a threshold score of 81.3. CONCLUSION: The results of this study validate the use of the KJOC score for evaluation of overhead athletes undergoing ulnar collateral ligament reconstruction. The KJOC score is the most sensitive score for detecting subtle changes in performance in the throwing athlete.

The effect of pitching biomechanics on the upper extremity in youth and adolescent baseball pitchers.

BACKGROUND: Increased pitch counts have been linked to increased complaints of shoulder and elbow pain in youth baseball pitchers. Improper pitching mechanics have not been shown to adversely affect the upper extremity in youth pitchers. HYPOTHESIS: The correct performance of 5 biomechanical pitching parameters correlates with lower humeral internal rotation torque and elbow valgus load, as well as higher pitching efficiency, in youth and adolescent pitchers. STUDY DESIGN: Descriptive laboratory study. METHODS: In sum, 169 baseball pitchers (aged 9-18) were analyzed using a quantitative motion analysis system and a high-speed video while throwing fastballs. The correct performance of 5 common pitching parameters was compared with each pitcher's age, humeral internal rotation torque, elbow valgus load, and calculated pitching efficiency. RESULTS: Motion analysis correlated with video analysis for all 5 parameters (P < .05). Youth pitchers (aged 9-13) performing 3 or more parameters correctly showed lower humeral internal rotation torque, lower elbow valgus load, and higher pitching efficiency (P < .05). CONCLUSIONS: Youth pitchers with better pitching mechanics generate lower humeral internal rotation torque, lower elbow valgus load, and more efficiency than do those with improper mechanics. Proper pitching mechanics may help prevent shoulder and elbow injuries in youth pitchers. CLINICAL RELEVANCE: The parameters described in this study may be used to improve the pitching mechanics of youth pitchers and possibly reduce shoulder and elbow pain in youth baseball pitchers.

Revision surgery for failed elbow medial collateral ligament reconstruction.

BACKGROUND: Although excellent results can be achieved in up to 90% of primary elbow medial ulnar collateral ligament reconstructions, retears of the ligament have been reported. As the number of primary reconstructions continues to increase, one could expect a commensurate increase in the number of revision medial collateral ligament reconstructions performed. HYPOTHESIS: Given the difficulty associated with revision procedures, the complication rate relative to primary reconstructions would increase while the percentage of athletes returning to their previous level of play would decrease. STUDY DESIGN: Case series; Level of evidence. 4. METHODS: This was a retrospective review of 15 patients who underwent revision surgery for retear of a reconstructed elbow medial collateral ligament. All patients had undergone previous elbow medial collateral ligament reconstruction and had new history and physical examination findings consistent with medial collateral ligament injury. Twelve subjects were professional baseball players and 3 were college-level players at the time of their revision procedure. Patients were evaluated at a minimum of 2 years after revision surgery. Outcomes were classified using the Conway scale. RESULTS: Average time to revision was 36 months. The technique used in the revision was the Jobe technique in 11 cases, DANE TJ in 3, and primary repair in 1. Thirty-three percent (5/15 excellent) returned to their previous level of play for at least 1 season. Additionally, there were 4 good, 2 fair, and 4 poor results. The ligament repair had a good outcome. Forty percent (6/15) of patients had complications, 1 of whom required a subsequent surgery (lysis of adhesions). One subject experienced a retear of the medial collateral ligament. CONCLUSION: The rate of return to play after revision medial collateral ligament surgery is much lower than after primary reconstruction. As was expected, the complication rate of revision surgery is higher as well. This study should help physicians when counseling baseball players who suffer retears of their medial collateral ligament.

Understanding shoulder and elbow injuries in baseball.

Repetitive overhead throwing exerts significant mechanical stress on the shoulder and elbow joint; this stress can lead to developmental anatomic changes in the young thrower. Asymptomatic pathology in the shoulder and elbow joint is prevalent and, with overuse, can progress to disabling injury. Joint injury occurs as a result of the body's inability to properly coordinate motion segments during the pitching delivery, leading to further structural damage. Identifying and preventing overuse is the key to avoiding injury, particularly in the young pitcher. Injury prevention and rehabilitation should center on optimizing pitching mechanics, core strength, scapular control, and joint range of motion.

The effect of tennis racket grip size on forearm muscle firing patterns.

BACKGROUND: Inappropriately sized tennis racket grip is often cited in the popular media as a risk factor for overuse injuries about the forearm and elbow. Currently, a hand measurement technique developed by Nirschl is commonly used by tennis racket manufacturing companies as the method for determining a player's "recommended" grip size. HYPOTHESIS: Quarter-inch changes from that recommended by Nirschl in tennis racket grip size will have no significant effect on forearm muscle firing patterns. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen asymptomatic Division I and II collegiate tennis players performed single-handed backhand ground strokes with rackets of 3 different grip sizes (recommended measurement, undersized (1/4) in, and oversized (1/4) in). Fine-wire electromyography was used to measure muscle activity in extensor carpi radialis longus and brevis, extensor digitorum communis, flexor carpi radialis, and pronator teres. Repeated-measure analysis of variance was used for within-group comparisons, comparing different grips in specified phases for backhand ground strokes (P

Arthroscopic treatment of posterolateral elbow impingement from lateral synovial plicae in throwing athletes and golfers.

BACKGROUND: Although elbow pain is common in throwing athletes and golfers, posterolateral impingement from a hypertrophic synovial plica is a rare but possibly underdiagnosed condition. PURPOSE: To evaluate the clinical results of arthroscopic treatment of symptomatic lateral elbow plicae in this athletic population. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twelve patients, 9 male and 3 female, whose mean age was 21.6 years (range, 17-33 years), were reviewed. There were 7 baseball pitchers, 2 softball players, and 3 golfers. All patients had diagnosed isolated lateral elbow plica; none had lateral epicondylitis, instability, osteochondritis dissecans, arthritis, loose bodies, or nerve conditions. The mean time from onset of symptoms to treatment was 9.25 months (range, 3-24.5 months). At a mean follow-up of 33.8 months (range, 24-65.5 months), patients were evaluated with a questionnaire and examination, based on the American Shoulder and Elbow Surgeons standardized elbow assessment and previously reported elbow outcome score. RESULTS: Posterolateral elbow pain was present in all patients. Fifty-eight percent (7 of 12 patients) complained of clicking or catching, whereas only 25% (3 of 12) experienced swelling or effusion. At elbow arthroscopy, a thickened synovial lateral plica was debrided in all cases. Ninety-two percent (11 of 12 patients) reported an excellent outcome with a mean elbow score of 92.5 points (maximum, 100 points). Return to competitive play averaged 4.8 months (range, 3-9.5 months). One patient with a fair outcome developed medial elbow instability that later required reconstructive surgery. CONCLUSION: Posterolateral elbow impingement from hypertrophic synovial plicae can cause significant pain and disability in throwing athletes and golfers. With careful diagnosis and exclusion of other elbow problems, treatment with arthroscopic debridement and focused rehabilitation is highly successful and allows these athletes to return to their previous level of play.

Shoulder injuries in golf.

Although often perceived as a leisurely activity, golf can be a demanding sport, which can result in injury, usually from overuse and sometimes from poor technique. The shoulder is a commonly affected site, with the lead shoulder, or the left shoulder in the right-handed golfer, particularly vulnerable to injury. A thorough understanding of the biomechanics of the golf swing is helpful in diagnosing and managing these injuries. Common shoulder problems affecting golfers include subacromial impingement, acromioclavicular arthrosis, rotator cuff tear, glenohumeral instability, and glenohumeral arthrosis. Although the majority of patients with these disorders will respond to nonsurgical treatment, including rest and a structured program of physical therapy, further benefits can be obtained with subtle modifications of the golf swing. Those golfers who fail to respond to nonsurgical management can often return to competitive play with appropriate surgical treatment.

An anatomic evaluation of the active compression test.

The goal of this study was to describe the anatomic relationships present during the active compression test. Four pairs of cadaveric shoulders were positioned to simulate the active compression test. The shoulders were embedded in polyurethane and evaluated in the axial and coronal planes with a planer. In the axial plane, all internally rotated shoulders demonstrated contact between the lesser tuberosity and subscapularis tendon and the superior aspect of the glenoid and labrum. In the externally rotated position, there was no contact between the superior structures of the shoulder. In the coronal plane, the internally rotated specimens revealed contact between the supraspinatus tendon and the lateral aspect of the acromion. There was no contact between the supraspinatus tendon and the acromion when the shoulders were externally rotated in the coronal plane. The results demonstrate that the active compression test can be used to assist in the diagnosis of superior labrum anterior-posterior lesions as well as other shoulder pathology.