Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers.

The throwing shoulder in pitchers frequently exhibits a paradox of glenohumeral joint motion, in which excessive external rotation is present at the expense of decreased internal rotation. The object of this study was to determine the role of humeral head retroversion in relation to increased glenohumeral external rotation. Glenohumeral joint range of motion and laxity along with humeral head and glenoid version of the dominant versus nondominant shoulders were studied in 25 professional pitchers and 25 nonthrowing subjects. Each subject underwent a computed tomography scan to determine bilateral humeral head and glenoid version. The throwing group demonstrated a significant increase in the dominant shoulder versus the nondominant shoulder in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees, and external rotation in the scapular plane. Internal rotation was decreased in the dominant shoulder. Total range of motion, anterior glenohumeral laxity, and posterior glenohumeral laxity were found to be equal bilaterally. The nonthrowing group demonstrated no significant difference in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees or external rotation in the scapular plane between shoulders, and no difference in internal rotation at 90 degrees, total motion, or laxity. A comparison of the dominant shoulders of the two groups indicated that both external rotation at 90 degrees and humeral head retroversion were significantly greater in the throwing group.     

Glenohumeral range of motion and stiffness in professional baseball pitchers

PURPOSE: This study was conducted to perform kinematic measures in a group of asymptomatic professional baseball pitchers to determine side-to-side differences in passive glenohumeral range of motion (ROM) and stiffness. We hypothesized that the throwing shoulder in asymptomatic pitchers would display greater passive glenohumeral stiffness than the contralateral nonthrowing shoulder. METHODS: Thirty-four professional baseball pitchers had bilateral assessments for passive glenohumeral ROM and stiffness during a single test session. ROM and stiffness measures were obtained objectively using standard goniometry and instrumented stress arthrometry, respectively. RESULTS: The throwing shoulder had significantly less (-8.5 degrees) internal rotation and significantly more external rotation (5.1 degrees) than the nonthrowing shoulder (P < 0.01). Passive joint stiffness was not significantly different between the throwing and nonthrowing shoulder, and anterior joint stiffness was significantly greater than posterior joint stiffness for both shoulders (P < 0.05). CONCLUSIONS: The repetitive stress of long-term throwing creates altered glenohumeral rotational patterns in the throwing shoulder of the professional baseball pitcher without compromising the joint's passive restraining quality.     

Shoulder rotational properties of throwing athletes

Throwing arm injuries are common and often related to the shoulder external and internal rotation. Quantitative assessment may provide new insights to physical assessment and options for treatment. After having signed IRB approved consents and filled out injury questionnaires, 96 baseball pitchers were examined on both shoulders using a custom-made wireless device. The resistance onset angle (ROA), end-point angle (EPA), shoulder rotational flexibility (SRF) in both external and internal rotation, and rotational ranges of motion (ROM) of both shoulders were determined. About 34% of subjects had surgeries on their throwing arm. Another 15% of subjects had throwing arm injuries that did not require surgical treatments. The throwing arm had significantly lower internal ROA, EPA and SRF, but significantly higher external ROA, EPA and SRF than the non-throwing arm. There were significant differences in shoulder rotational properties among groups with different surgery locations. Subjects with shoulder surgeries had greater internal rotation flexibility of their throwing arm than those with surgeries on the elbow. Throwers with injury and surgery history had significantly different shoulder rotational properties. Abnormal shoulder rotational properties may be related to throwing arm injuries. A better understanding of their relationship may lead us to effective preventive measures of throwing arm injuries.     

Shoulder range of motion characteristics in collegiate baseball players.

BACKGROUND: To determine range of motion and capsular characteristics of dominant and nondominant shoulders in baseball players. Our hypothesis was that there is a significant difference between dominant and nondominant range of motion in collegiate baseball players with unoperated and without shoulder pain. METHODS: Design: prospective, range of motion measurements during regular season. Setting: two collegiate baseball teams in Houston. Participants: 15 pitchers and 23 position players. Main outcome measures: shoulder range of motion was evaluated by goniometric technique in all baseball players. Horizontal adduction (cross body reach test) and active internal rotation (reach behind back) in standing position and external rotation and internal rotation in supine lying position were measured for each player. RESULTS: Average external rotation with the arm in 90 degrees of abduction was significantly greater and average internal rotation was less in the dominant shoulder than in the nondominant shoulders, both in pitchers and position players. There was no statistical difference in shoulder horizontal adduction. Both dominant and nondominant shoulders of pitchers had greater average range of motion in horizontal adduction and external rotation at 90 degrees of abduction and less average internal rotation than those of position players. Although there was a significant difference in active internal rotation as cm between dominant and nondominant shoulders both in both groups, no difference was found between pitchers and position players. CONCLUSIONS: Differences in the range of motion in the throwing shoulder of baseball players exist involved in overhead throwing motions and should be considered in rehabilitation of the upper extremity after injury and in the prevention of injury for pitchers and position players.     

MR findings in asymptomatic shoulders: a blind analysis using symptomatic shoulders as controls.

We performed a blind prospective analysis of the shoulders of 20 asymptomatic volunteers, aged 25 to 55 years, to determine the frequency of magnetic resonance (MR) findings considered abnormal in symptomatic patients. Twenty symptomatic patients were used as controls. With regard to the asymptomatic shoulders, all 20 had intact rotator cuff tendons, although six (30%) of the tendons had abnormal internal signal, and one (5%) had abnormal morphology. Subdeltoid and subacromial fat planes were intact in 20 (100%) and 19 (95%) shoulders respectively. Subdeltoid or subacromial fluid was not present in any shoulder. Acromioclavicular osteophytes and supraspinatus depression were seen in seven (35%) and six (30%) respectively. The glenoid labrum was intact in all volunteers, although it had abnormal internal signal in 10 (50%). MR findings of abnormal signal in the glenoid labrum, and of abnormal signal and morphology of the rotator cuff tendons, supraspinatus depression, and acromioclavicular osteophytes have been reported as signs of instability, tendinitis, and impingement. Similar findings were seen in asymptomatic volunteers, indicating that these findings may not be a sign of clinically significant pathology.     

Increased signal intensity in the normal glenoid labrum in MR imaging: diagnostic pitfalls caused by the magic-angle effect.

PURPOSE: To determine the effect of the magic-angle effect on the MR signal in the posterosuperior portion of the glenoid labrum. METHODS: MR imaging of 15 arthroscopically evaluated shoulders, five with posterosuperior labrum injury and ten intact, was retrospectively reviewed. In the first part of the study, the signal intensity of the posterosuperior labrum on gradient-recalled echo (GRE) T2*-weighted axial images was correlated with the arthroscopy findings. The second part of the study was designed to illustrate the orientation-dependent signal that occurs in the posterosuperior labrum of three asymptomatic volunteers when imaged in the conventional supine position and in a position similar to Trendelenburg's. Another three volunteers were examined with GRE T2*-weighted axial images to assess the echo-time (TE)-dependent signal in the labrum. RESULTS: The signal increase in the posterosuperior labrum was identified not only in the injured labra but also in nine of 10 intact labra. In the volunteers' studies, the signal in the posterosuperior labrum changed according to the examinees' positions (conventional supine or similar to Trendelenburg's) and according to TE. CONCLUSIONS: Increased signal intensity due to the magic-angle effect may be misdiagnosed as a labrum injury. Awareness of this pitfall is particularly important in MR imaging of throwing athletes whose posterosuperior labra are frequently injured by posterosuperior glenoid impingement.     

Greater tuberosity notch: an important indicator of articular-side partial rotator cuff tears in the shoulders of throwing athletes.

We examined the location of rotator cuff tears, associated labral injuries, and notches on the greater tuberosity of the humeral head in shoulders of throwing athletes. Arthroscopic findings (rotator cuff tear, labral condition, and greater tuberosity notch) as well as other factors (duration of playing baseball, range of motion, and joint laxity) of 61 baseball players were retrospectively studied. The presence of a greater tuberosity notch was also evaluated for by plain radiographs. Forty patients had articular-side partial rotator cuff tears, most of which occurred in the interval between the supraspinatus and infraspinatus tendons. The existence of a rotator cuff tear was not related to the range of motion, joint laxity, the detachment of the superior glenoid labrum, or posterosuperior labral injury. Greater tuberosity notches were recognized in 38 shoulders by arthroscopy and most were detected on plain radiographs. The presence of a notch was significantly related to the existence of a rotator cuff tear, while the size of the notch was significantly related to the depth and width of the tear. The greater tuberosity notch seems to be one of the most important diagnostic indicators for a rotator cuff tear in throwing athletes.     

Current concepts in the diagnosis and treatment of shoulder instability in athletes

Glenohumeral joint instability is a fairly common clinical disorder in athletes, especially in sports that involve the throwing motion. The direction of shoulder instability can be anterior, inferior, posterior, or multidirectional. The cause can be trauma, congenital laxity, or voluntary muscle action. Normal shoulders that have been disrupted by injury respond well to surgical correction. Shoulders that have inherently lax supporting structures, as found in patients with atraumatic and voluntary dislocation, have less consistent success with surgical repair. A common condition encountered in the shoulder of a throwing arm is anterior subluxation, which can be diagnosed by the positive apprehension sign and confirmed by arthroscopy. A torn glenoid labrum is a common injury also. Improvement in the diagnosis and treatment of shoulder disorders has been made recently by arthroscopy which allows direct visualization of the joint; many conditions can now be corrected by means of arthroscopic surgery. Radiographic techniques have also been improved.     

Glenoid labrum: preliminary work with use of radial-sequence MR imaging

The authors describe a magnetic resonance imaging method for examination of the glenoid labrum of the shoulder joint that utilizes a radial fast-imaging sequence. Seven shoulders were examined: a total of five in three healthy asymptomatic volunteers, one in a symptomatic patient not suspected of having a lesion of the glenoid labrum, and one in a patient with recurrent shoulder dislocation and surgical proof of an extensive tear of the labrum. The preliminary results suggest that this technique may advantageously demonstrate pathologic changes in the glenoid labrum and may contribute to the evaluation of the unstable and painful shoulder.     

Hypoplasia of the glenoid neck of the scapula: imaging findings and report of 16 patients

OBJECTIVE: Our purpose was to describe the primary and associated imaging findings in patients with glenoid hypoplasia required for an accurate diagnostic appraisal of this uncommon abnormality. METHODS: The medical records and imaging studies of 16 patients with glenoid hypoplasia were retrospectively reviewed. Plain films were available in all patients, arthrography in 2, computed tomography (CT) in 5, CT arthrotomography in 3, magnetic resonance (MR) imaging in 9, and MR arthrography in 3 patients. The imaging studies were reviewed with special attention to the primary and secondary findings associated with glenoid hypoplasia. RESULTS: On radiographs, the 21 abnormal shoulders documented in the 16 patients with glenoid hypoplasia had an irregular (n=15) or shallow and smooth (n=6) articular surface of the glenoid. Computed tomography findings showed subluxation of the humeral head in 5 cases. On MR images, the hypoplastic bony glenoid and scapular neck were replaced by abnormal tissue of inhomogeneous signal intensity, showing the signal intensity characteristics of fibrocartilage (n=6) or fat (n=5). Widening of the inferior glenohumeral joint space was seen in all cases. Magnetic resonance imaging or MR arthrography revealed variable abnormalities of the labrum, including enlargement (10 shoulders), detachment of labrum from the bony glenoid (6 shoulders), intrasubstance tear (4 shoulders), and perilabral cyst (2 shoulders). The posterior labrum was absent (n=1) or torn (n=1) in one patient with bilateral deformity. Other findings included partial tear of the subscapularis tendon (n=1) and rotator cuff atrophy (n=1) and tear (n=2). CONCLUSION: Glenoid hypoplasia is a developmental skeletal anomaly comprising a spectrum of associated osseous and cartilaginous changes of the articular cartilage and glenoid labrum. Cross-sectional imaging studies, with or without arthrography, may help further characterize associated derangements of the shoulder, some of which are indicative of shoulder instability.     

Prevalence of the Bennett lesion of the shoulder in major league pitchers

BACKGROUND: The Bennett lesion is a mineralization of the posterior inferior glenoid noted in overhead throwing athletes. Although previous studies have debated appropriate treatment of the lesion, no studies have indicated the lesion prevalence in throwing athletes. HYPOTHESIS: The Bennett lesion is more common than previously believed and may represent an asymptomatic finding. STUDY DESIGN: Uncontrolled retrospective review. METHODS: Fifty-five asymptomatic major league pitchers underwent routine preseason radiographic screening. Radiographs were reviewed for the presence of a Bennett's lesion. Player demographics, pitching, and baseball records were reviewed to obtain the patient's dominant arm, age, years and innings pitched, and time on the disabled list or surgery. RESULTS: Twelve pitchers (22%) were noted to have a radiographic Bennett lesion. No statistically significant difference was noted in age, years pitched, or innings pitched between pitchers with and without a Bennett lesion. No player who demonstrated a Bennett lesion required surgical treatment for shoulder pain during his time with the club. Two players required time on the disabled list, but neither player had complaints of posterior shoulder pain. CONCLUSIONS: This lesion is a relatively common finding in major league pitchers. Concomitant pathology should be suspected when evaluating throwers with posterior shoulder pain and this lesion.     

Glenoid labrum tears related to the long head of the biceps

Tears of the glenoid labrum were observed in 73 baseball pitchers and other throwing athletes who underwent arthroscopic examination of the dominant shoulder. Most of the tears were located over the anterosuperior portion of the glenoid labrum near the origin of the tendon of the long head of the biceps muscle into the glenoid. At arthroscopy, the tendon of the long head of the biceps appeared to originate through and be continuous with the superior portion of the glenoid labrum. In many cases it appeared to have pulled the anterosuperior portion of the labrum off the glenoid. This observation was verified at arthroscopy by viewing the origin of the biceps tendon into the glenoid labrum as the muscle was electrically stimulated. With stimulation of the muscle, the tendinous portion became quite taut, particularly near its attachment to the glenoid labrum, and actually lifted the labrum off the glenoid. Three-dimensional high-speed cinematography with computer analysis revealed that the moment acting about the elbow joint to extend the joint through an arc of about 50 degrees was in excess of 600 inch-pounds. The extremely high velocity of elbow extension which is generated must be decelerated through the final 30 degrees of elbow extension. Of the muscles of the arm that provide the large deceleration forces in the follow-through phase of throwing, only the biceps brachii traverses both the elbow joint and the shoulder joint. Additional forces are generated in the biceps tendon in its function as a "shunt" muscle to stabilize the glenohumeral joint during the throwing act.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of shoulder proprioception in the female softball athlete

BACKGROUND: There have been reports of overhand throwing athletes having decreased joint position sense in their dominant shoulder as compared with the nondominant shoulder. Very little research, however, exists concerning joint position sense in the female athlete. HYPOTHESIS: Female softball athletes have decreased joint position sense in their dominant shoulder as compared with their nondominant shoulder. STUDY DESIGN: Factorial design with investigation of multiple independent variables. METHODS: Joint position sense was assessed in 50 female softball players and 50 nonthrowing female athletes by using an inclinometer during four glenohumeral joint motions. Both the dominant and nondominant shoulders were assessed and error scores were calculated to describe joint position sense. Data were collected during the course of a fall semester and analyzed by using a mixed model analysis of variance with repeated measures on the dependent variable (error scores). RESULTS: A significant group by movement interaction was observed, with the softball athletes demonstrating significantly greater external rotation error scores than the nonthrowing athletes. CONCLUSION: We failed to reject the null hypothesis. Increased error scores (less joint position sense) were observed in both arms of subjects in the softball group. Clinical Relevance: This study suggests that there is decreased shoulder proprioception in asymptomatic female athletes involved in overyhand throwing sports, which may predispose them to injury.     

Glenohumeral internal rotation deficits in professional pitchers enrolled in an internal rotation stretching program

BACKGROUND: Repetitive throwing motion creates increased external rotation and decreased internal rotation in the glenohumeral joint. There is controversy regarding the contribution of osseous and soft tissue adaptations to these changes in rotation. OBJECTIVE: To evaluate internal rotation deficits in the professional baseball thrower's shoulder and determine the impact of an internal rotation stretch program on that deficit. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Eighty-five male professional pitchers were evaluated in this study. Players were divided into 2 groups based on length of participation in an appropriate internal rotation stretch program. Data were collected on internal and external rotations and total range of motion in both dominant and nondominant arms using a goniometer. Internal rotation deficit (the lack of internal rotation relative to the opposite side) was calculated. Generalized comparative statistical tests were used. RESULTS: Pitchers with 3 or more years in a stretch program (group 1) had greater internal rotation (74.3 degrees vs 54.3 degrees ) and greater total range of motion (217.0 degrees vs 194.2 degrees ) in dominant shoulders than did pitchers with less than 3 years (group 2). Total range of motion was greater in the dominant than in the nondominant arm for group 1. Internal rotation deficit in dominant arms was significantly greater for group 2 than for group 1. The analysis of dominant arm rotation relative to years in an internal rotation stretching program for pitchers in both groups showed a progressive increase in both internal rotation and total arc of motion with the number years in such a program plateauing after year 3. CONCLUSION: The throwing motion shifts the total arc of motion toward external rotation and diminishes internal rotation. The increased external rotation may be attributable to increased humeral retroversion. The internal rotation deficit, however, is caused by soft tissue adaptations that can be addressed by consistent participation in a stretching program focused on internal rotation.     

Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement

BACKGROUND: Alterations in glenohumeral range of motion, including increased posterior shoulder tightness and glenohumeral internal rotation deficit that exceeds the accompanying external rotation gain, are suggested contributors to throwing-related shoulder injuries such as pathologic internal impingement. Yet these contributors have not been identified in throwers with internal impingement. HYPOTHESIS: Throwers with pathologic internal impingement will exhibit significantly increased posterior shoulder tightness and glenohumeral internal rotation deficit without significantly increased external rotation gain. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Eleven throwing athletes with pathologic internal impingement diagnosed using both clinical examination and a magnetic resonance arthrogram were demographically matched with 11 control throwers who had no history of upper extremity injury. Passive glenohumeral internal and external rotation were measured bilaterally with standard goniometry at 90 degrees of humeral abduction and elbow flexion. Bilateral differences in glenohumeral range of motion were used to calculate glenohumeral internal rotation deficit and external rotation gain. Posterior shoulder tightness was quantified as the bilateral difference in passive shoulder horizontal adduction with the scapula retracted and the shoulder at 90 degrees of elevation. Comparisons were made between groups with dependent t tests (P < .05). RESULTS: The throwing athletes with internal impingement demonstrated significantly greater glenohumeral internal rotation deficit (P = .03) and posterior shoulder tightness (P = .03) compared with the control subjects. No significant differences were observed in external rotation gain between groups (P = .16). CLINICAL RELEVANCE: These findings could indicate that a tightening of the posterior elements of the shoulder (capsule, rotator cuff) may contribute to impingement. The results suggest that management should include stretching to restore flexibility to the posterior shoulder.     

Magnetic resonance imaging of the asymptomatic shoulder of overhead athletes: a 5-year follow-up study

BACKGROUND: Although several studies have described magnetic resonance imaging findings in shoulders of asymptomatic volunteers, no such investigation has been performed on asymptomatic dominant and nondominant shoulders of elite overhead athletes. HYPOTHESIS: Asymptomatic dominant shoulders of elite overhead athletes may have a higher incidence of magnetic resonance imaging abnormalities than either their nondominant shoulder or shoulders of asymptomatic volunteers. STUDY DESIGN: Prospective cohort study. METHODS: Detailed magnetic resonance imaging scans of asymptomatic dominant and nondominant shoulders of elite overhead athletes were obtained. Three experienced musculoskeletal radiologists interpreted each scan for multiple variables, including rotator cuff appearance. Images from a surgical control group were intermixed to assess accuracy and control for observer bias. A 5-year follow-up interview was performed to determine whether magnetic resonance imaging abnormalities found in the initial stage of the study represented truly clinical false-positive findings or symptomatic shoulders in evolution. RESULTS: Eight of 20 (40%) dominant shoulders had findings consistent with partial- or full-thickness tears of the rotator cuff as compared with none (0%) of the nondominant shoulders. Five of 20 (25%) dominant shoulders had magnetic resonance imaging evidence of Bennett's lesions compared with none (0%) of the nondominant shoulders. None of the athletes interviewed 5 years later had any subjective symptoms or had required any evaluation or treatment for shoulder-related problems during the study period. CONCLUSIONS: Magnetic resonance imaging alone should not be used as a basis for operative intervention in this patient population.     

Shoulder arthroscopy: its role in evaluating shoulder disorders in the athlete

We retrospectively reviewed 100 initial shoulder arthroscopies from a general sports medicine orthopaedic practice to determine if arthroscopy is helpful diagnostically and to see if specific lesions correlate well with specific diagnoses. Seventy-two percent of the patients in the review had glenoid labral tears. Ninety-two percent of patients who had a diagnosis of either recurrent anterior dislocation or recurrent anterior subluxation demonstrated a tear of the anterior inferior margin of the glenoid labrum. Sixty-eight percent of patients with a diagnosis of impingement demonstrated tears at the superior margin of the labrum. There was a significant difference between throwing and nonthrowing athletes. Partial rotator cuff tears were noted in 18 patients, the majority occurring in throwing athletes. Other abnormalities, such as degenerative joint changes and biceps tendon lesions, were also noted at the time of arthroscopy. A large number of glenoid labral tears found at the time of arthroscopy appeared to be associated with conditions other than instability, which may or may not affect the throwing athlete. There also appeared to be a high correlation between tears in the anterior inferior glenoid labrum and anterior instability. Arthroscopy enabled us to identify other significant information about the status of the biceps tendon or the undersurface of the rotator cuff. These are areas in which problems might otherwise have been missed. Degenerative changes of the articular surface, not apparent on plain radiographs, may also be better evaluated arthroscopically.