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Eighty-three athletes with medial elbow instability underwent reconstruction of the anterior band of the ulnar collateral ligament with a muscle-splitting approach without transposition of the ulnar nerve. The purposes of this study were to describe postoperative neurologic outcomes in all 83 athletes and to describe the 2-year follow-up in 33 athletes. Postoperatively, 5% of this group had transient ulnar nerve symptoms, all of which resolved with nonoperative management. There were no reoperations for nerve dysfunction and no permanent nerve problems. At 2- to 4-year follow-ups, 93% of the highly competitive athletes who had not had a prior surgical procedure had an excellent result. All athletes, regardless of whether they had a prior procedure, were able to return to their sport. These surgical modifications to the ulnar collateral ligament reconstruction yielded a decreased postoperative complication rate and improved outcomes compared with the results of prior procedures.

The purpose of this study was to compare subjects with subacromial impingement and subjects with normal shoulders with respect to muscle activity. Fifteen subjects in each group were studied by means of fine-wire electromyography. The middle deltoid and rotator cuff muscles were evaluated during isotonic scaption from 30 to 120 degrees. Overall, the impingement group demonstrated decreased mean muscle activity in comparison with the group of normal subjects. The magnitude of diminished activity was statistically significantly different (P < .05) during the 30- to 60-degrees arc for the infraspinatus, subscapularis, and middle deltoid muscles; in addition, the infraspinatus muscle demonstrated significantly depressed activity during the 60- to 90-degrees arc. In the impingement group, the supraspinatus and teres minor revealed a diminution of muscle function in comparison with shoulders in the normal group; the difference was not significant. This study demonstrates that muscle activity in subjects with impingement is most notably decreased in the first arc of motion. Also of clinical relevance is the fact that the inferior force vector (from the infraspinatus and subscapularis) is less functional in subjects with impingement than is the superior compressive vector (from the supraspinatus). Thus, humeral head depression during the critical first portion of elevation may be insufficient in people with subacromial impingement.

Thirteen overhand-throwing athletes who failed at least 3 months of physical therapy while restricted from throwing and who demonstrated a positive modified relocation test at 90 degrees, 110 degrees, and/or 120 degrees were clinically and arthroscopically examined. On arthroscopic examination, all patients demonstrated articular surface pathology. Eleven patients had fraying of the undersurface of the rotator cuff, and 10 patients had fraying of the posterosuperior labrum. With 90 degrees shoulder abduction, 8 patients had rotator cuff contact with the posterosuperior labrum. When the shoulder was abducted to 110 degrees, all patients demonstrated such contact. At 120 degrees of abduction, 12 patients revealed contact. The presence or absence of pain during the modified relocation test correlated with the presence or absence of cuff contact with the posterosuperior labrum 79% of the time. Six patients had a positive modified relocation test at all levels of abduction. These patients included 2 with SLAP lesions, 1 with a Bankart lesion, and 1 with a complete tear of the rotator cuff.

The purpose of this study was to compare the effect of increasing loads and doubling speed on the deltoid and rotator cuff muscles during isotonic scapular plane abduction (scaption) with neutral humeral rotation. These muscles were studied in 16 volunteers with asymptomatic shoulders with the use of fine wire electromyography. The addition of load to the arm during scaption caused an increase in electromyographic activity during the first 90 degrees of motion. Furthermore electromyographic activity decreased during the final 30 degrees of motion with each increase in load. Doubling the speed caused an increase in electromyographic activity during the first 60 degrees of motion while causing a decrease in activity in the final 60 degrees. This study demonstrates the response of the rotator cuff and deltoid muscles to varying loads and speeds during the most basic shoulder motion. With the data obtained in this study, rehabilitation exercises and experimental shoulder models can be refined to reflect this more physiologic situation.

The purpose of this study was to describe the extra- and intra-articular anatomic relationships present during the Neer and Hawkins tests. Nine fresh-frozen cadaveric shoulders were positioned in the impingement position described by Neer (n = 5) or that described by Hawkins (n = 4), embedded in polyurethane, and studied with the use of a cross-sectional technique. All shoulders placed in the Neer position demonstrated soft tissue contact with the medial acromion and contact between the articular surface of the rotator cuff tendons and the anterosuperior glenoid rim. Shoulders placed in the Hawkins position demonstrated consistent contact between soft tissues and the coracoacromial ligament. In all Hawkins positioned shoulders, contact between the articular surface of the rotator cuff tendons and the anterosuperior glenoid was observed. The subscapularis tendon was deformed by the coracoid in 1 of the Hawkins positioned specimens. Although factors inherent to human subjects such as edema and muscle tone may influence the anatomy, these provocative tests for subacromial impingement appear to elicit contact consistent with impingement.

The primary restraint preventing humeral head translation is the capsuloligamentous system. Muscle forces can also decrease translation; however, the timing and magnitude of muscle response has not been previously reported. Fine wire electromyographic analysis of the biceps long head, anterior deltoid, pectoralis major, latissimus dorsi, and rotator cuff muscles was performed after an anterior translation force was applied to 15 normal shoulders. The reflex response time (time to 5% maximal muscle test), the protection response time (time to 20% maximal muscle test), the duration of the protection response, and the magnitude of the protection response were calculated. The shoulder reaction data showed 2 consistent patterns. Activation of the anteriorly located muscles preceded the posteriorly located muscles, and the rotator cuff muscles fired with greater magnitude than the more peripherally located muscles.

The purpose of this study was to describe the electromyographic (EMG) pattern and relative intensities of 8 shoulder muscles during the volleyball serve and spike in 15 professional or collegiate-level athletes. The EMG analysis was synchronized with high-speed cinematography to discern phases of the spike and serve. During the spike, the anterior deltoid and supraspinatus functioned together to elevate and place the humerus throughout all phases. During cocking the infraspinatus and teres minor acted together to rotate the humerus externally. In acceleration, however, these muscles behaved independently; activity of the teres minor remained high, whereas the activity of the infraspinatus declined. The anterior wall muscles functioned to decelerate the humerus during cocking and acted as internal rotators during acceleration. Muscle activities recorded for the serve followed similar patterns as those seen for the spike, but with lower amplitudes. These data illustrate the complex sequence of shoulder muscle activity necessary to play competitive volleyball.

The inability to perform the "liftoff" test has been attributed to a subscapularis muscle or tendon injury. The goals of this study were to evaluate the activity of the glenohumeral muscles during performance of the "liftoff" maneuver and to identify the most effective initial upper extremity placement that isolates the subscapularis musculotendinous unit. In the first phase of this study 15 subjects accomplished four proposed versions to the "liftoff" test while their intramuscular electromyographic activity in select glenohumeral muscles was recorded. The second phase of this study assessed the ability of five subjects with a nonfunctional subscapularis musculotendinous unit to perform the same proposed versions. On the basis of electromyographic data none of the proposed versions to the "liftoff" maneuver isolated the upper and lower subscapularis muscle from either the teres major, latissimus dorsi, posterior deltoid, or rhomboid muscles (p > 0.05). In the presence of a nonfunctional subscapularis musculotendinous unit, the subjects were able to perform all of the proposed versions of the "liftoff" maneuver except one: elevation of the dorsum of the hand from the posterior-inferior border of the scapula (maximum internal rotation test). Although significant electromyographic activity was generated in the potentially confounding shoulder girdle muscles during the maximum internal rotation "liftoff" test, a successful test appears to be dependent on the isolated glenohumeral internal rotation function of the subscapularis muscle.

This study compared the electromyographic activity of rotator cuff and scapular muscles between subjects with anterior instability and subjects with normal shoulders. Thirty-eight patients were studied; 23 had anterior instability that was subsequently surgically confirmed, and 15 had normal shoulders. Fine wire electrodes were inserted into the subscapularis (upper and lower portions), supraspinatus, infraspinatus, rhomboid, serratus anterior, and trapezius (upper and lower portions) muscles. Abduction, scapular plane abduction (scaption), and forward flexion were performed over the range of motion and later divided into 30 degrees intervals. In both abduction and scaption, the supraspinatus demonstrated significantly less electromyographic activity from 30 degrees to 60 degrees in shoulders with anterior instability compared with normal shoulders (p < 0.05). During all three motions, shoulders with anterior instability demonstrated significantly less electromyographic activity in the serratus anterior when compared with normal shoulders (p < 0.05). This occurred at 30 degrees to 120 degrees of abduction and at 0 degree to 120 degrees of scaption and forward flexion. None of the other muscles demonstrated significant differences. These differences during planar motions were similar to those demonstrated during challenging overhead sport motions. Early rehabilitation efforts should focus both on the rotator cuff and scapular muscles to establish smooth, coordinated shoulder motion.

We did an anterior capsulolabral reconstruction for recurrent subluxation or dislocation of the shoulder in 75 athletes after failure of conservative therapy. Average follow-up was 39 months (range 28 to 60 months). The results were 77% excellent, 75% good, 3% fair, and 5% poor. Seventy-five percent of the professional and 100% of the college baseball players returned to their previous level of competition. Seventy-seven percent of the professional pitchers were able to return to professional pitching. The range of motion at follow-up was full in 79% of the athletes. No infections or nerve injuries occurred. The anterior capsulolabral reconstruction procedure combined with an early rehabilitation program appears to provide an improved outcome compared with previously reported procedures for anterior instability of the shoulder in athletes., (Copyright © 1992 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

The upper extremity is vulnerable to injury during the baseball pitch because of the repetitious nature of the action, the extremes in range of motion, and the high angular velocities and torques generated at the shoulder and elbow. Hence this study was designed to describe the muscle-firing patterns through fine-wire electromyography in 29 muscle bellies in the upper extremities of skilled pitchers during the fastball pitch. The results demonstrated that the muscles functioned with precise timing for joint stabilization to prevent injury, joint activation to transfer forces to the ball, and joint deceleration to dissipate forces after ball release. The synchrony of reciprocal and sequential muscle contraction necessary to accomplish these functions was clearly evident. This study provides a better understanding of the coordinated sequence of muscle activity during the throwing motion; this understanding is crucial to the development of exercise protocols and surgical procedures used for treatment and prevention of shoulder and elbow injuries in the throwing athlete., (Copyright © 1992 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)