Ronald E. Glousman

Dynamic electromyographic analysis of the throwing shoulder with glenohumeral instability

Fifteen male athletes who were skilled in throwing and who had chronic anterior instability of the shoulder (Group 1) were evaluated by dynamic intramuscular electromyography while pitching a baseball. Indwelling wire electrodes recorded the levels of activity in the biceps, middle deltoid, supraspinatus, infraspinatus, pectoralis major, subscapularis, latissimus dorsi, and serratus anterior throughout the entire pitching sequence. These signals were synchronized electronically with records of the pitch that were made using high-speed photography. The pitch was divided into five phases: wind-up, early cocking, late cocking, acceleration, and follow-through. The results were compared with previous identical studies of twelve healthy, uninjured male athletes who were skilled in throwing (Group 2). Activity increased mildly in the biceps and supraspinatus in Group 1 as compared with Group 2. Similar patterns of activity were demonstrated in the deltoid. In Group 1 the infraspinatus had increased activity during early cocking and follow-through but had decreased activity during late cocking. The pectoralis major, subscapularis, latissimus dorsi, and serratus anterior in Group 1 all were shown to have markedly decreased activity. The study revealed a difference between Groups 1 and 2 in all of the muscles of the shoulder that were tested with the exception of the deltoid. The mildly increased activity levels of the biceps and supraspinatus that were found in Group 1 may compensate for anterior laxity. The marked reduction in activity in the pectoralis major, subscapularis, and latissimus dorsi added to the anterior instability by decreasing the normal internal-rotation force that is needed during the phases of late cocking and acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)

Medial instability of the elbow in throwing athletes. Treatment by repair or reconstruction of the ulnar collateral ligament.

From September 1974 to December 1987, seventy-one patients were operated on for valgus instability of the elbow. The average length of follow-up of sixty-eight patients (seventy operations) was 6.3 years (range, two to fifteen years). At the operation, a torn or incompetent ulnar collateral ligament was found. Fourteen patients had a direct repair of the ligament, and fifty-six had a reconstruction of the ligament using a free tendon graft. The result was excellent or good in ten patients in the repair group and in forty-five (80 per cent) in the reconstruction group. Seven of the fourteen patients who had a direct repair returned to the previous level of participation in their sport. Of the fifty-six who had a reconstruction, thirty-eight (68 per cent) returned to the previous level of participation. Twelve of the sixteen major-league baseball players who had a reconstruction as the primary operation (no previous operation on the elbow) were able to return to playing major-league baseball, and two of the seven major-league players who had a direct repair returned to playing major-league baseball. Previous operations on the elbow decreased the chance of returning to the previous level of sports participation (p = 0.04). Fifteen patients had postoperative ulnar neuropathy. This was transient in six patients, only one of whom was unable to return to the previous level of sport. The other nine patients had an additional operation for the neuropathy; four were able to return to the previous level of sport.

Anterior capsulolabral reconstruction of the shoulder in athletes in overhand sports

From April 1, 1985, through June 30, 1987, 25 skilled athletes with shoulder pain secondary to anterior gle nohumeral instability that had failed to improve with conservative therapy had an anterior capsulolabral re construction. All but one athlete completed a formal rehabilitation program with an average followup of 39 months. The results at followup were rated excellent in 68%, good in 24%, fair in 4%, and poor in 4%. Seven teen patients returned to their prior competitive level for at least 1 year. This operation and rehabilitation program may allow many athletes who participate in overhand activities or throwing sports to return to their prior level of competition.

An electromyographic analysis of the elbow in normal and injured pitchers with medial collateral ligament insufficiency

Electromyography and high-speed film were used to examine the muscle activity in the elbows of pitchers with medial collateral ligament insufficiency compared to the activity in uninjured elbows. Ten competitive baseball pitchers with medial collateral insufficiency and 30 uninjured competitive pitchers were tested while throwing the fastball and the curveball. The extensor carpi radialis brevis and longus in the injured pitchers showed greater activity than in the uninjured pitchers for both pitches. The triceps, flexor carpi radialis, and pronator teres all showed less activity in the injured pitchers during the fastball, but only the triceps had less activity during the curveball. The differences were seen during the late cocking and acceleration phases, which place the greatest stress on the medial collateral ligament. If the flexor carpi radialis and pronator teres were substituting for the deficient medial collateral lig ament and functioning as dynamic stabilizers, one would expect enhanced muscle activity. However, the opposite was found. This pattern of asynchronous mus cle action with medial collateral ligament injury may predispose the joint to further injury. The muscular differences seen are critical to the understanding of the pathomechanics of patients with medial collateral liga ment deficiency, and provide a basis for rehabilitation.

Dynamic stability of the elbow: Electromyographic analysis of the flexor pronator group and the extensor group in pitchers with valgus instability

The medical collateral ligament is a common site of injury in baseball pitchers, causing substantial morbidity and loss of pitching time. Twenty-six skilled baseball pitchers with medial collateral ligament insufficiency were studied before surgery with high-speed cinematography and fine-wire electromyography of eight muscles around the elbow. Data from the pitchers with injured elbows were compared with data obtained from uninjured pitchers. The flexor carpi radialis muscle in the pitchers with medial collateral ligament deficiencies revealed significantly decreased firing during the acceleration and deceleration phase of the fastball when compared with that of the pitchers with normal elbows, and the flexor carpi radialis muscle was significantly depressed during the early cocking and deceleration phases. The extensor muscles revealed slightly increased activity in the injured elbows; however, this was not statistically significant. Although the muscles of the flexor pronator group (especially the flexor carpi ulnaris muscle and the flexor digitorum superficialis muscles) are anatomically positioned to provide dynamic stability of the elbow, they did not demonstrate increased electrical activity in pitchers with medial collateral ligament deficiencies. This finding suggests that the muscles on the medial side of the elbow do not supplant the role of the medial collateral ligament during the fastball pitch.

Gore-Tex prosthetic Ligament in Anterior Cruciate Deficient Knees

Reconstruction for symptomatic anterior cruciate defi cient knees has yielded varying success rates. Pros thetic cruciate replacement has recently become a po tentially attractive alternative. The results of the Gore- Tex polytetrafluoroethylene ligament, which is intended as a permanent replacement, are reported. Eighty-two patients were followed prospectively, mean age was 28 years (range, 16 to 51 years) and mean followup was 18 months (range, 12 to 30 months). Subjective scores improved in all categories, including pain, swelling, giving way, locking, and stair climbing. All patients without complications had no episodes of actual giving way, considered themselves improved, and returned to activities of daily living at 3 weeks and athletics at 8 months. Range of motion lacking at 3 months was 2° of extension and 10° of flexion, and at 12 months was 0° of extension and 4° of flexion. All mean objective data, including the anterior drawer, Lachman, and pivot shift, demonstrated im provement at final followup. Cybex testing revealed improvement in relative quadriceps strength from 88% to 99%. The KT-1000 Arthrometer showed improve ment in the injured-normal knee difference score throughout the follow-up period. Of importance is that while final objective data was improved over initial data, an early nonprogressive shift toward loosening was indicated by worsening of the drawer, Lachman, pivot shift, and KT-1000 scores. This shift may be attributed to resorption of interposed soft tissue, creep, or loosening of the graft. Subjective scores remained stable after improving. Complications included four ruptures, four chronic sterile effusions with partial attenuation, one infection, and one symptomatic loose body. There were 14 re- operations (17%), a total of 15 complications (18%), and 7 permanent complications (8%). There were no deaths, pulmonary emboli, or medical complications. We feel that the Gore-Tex ligament may become a rational alternative for anterior cruciate reconstruction in selected cases of prior reconstructive failure or older, less active individuals with symptomatic instability. Sur gical dissection is minimal, with maintenance of autog enous tissues yielding rapid recovery and low morbidity. The results presented are based upon preliminary data, and indications for expanded use of the ligament and definitive conclusions regarding the natural history of the graft will have to await further long-term followup.

Anterior capsulolabral reconstruction of the shoulder in athletes

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.

A Biomechanical Comparison of 2 Technical Variations of Double-Row Rotator Cuff Fixation The Importance of Medial Row Knots

Background Previous studies have shown comparable biomechanical properties of double-row fixation versus double-row fixation with a knotless lateral row. SutureBridge is a construct that secures the cuff with medial row mattress suture anchors and knotless lateral row fixation of the medial suture ends. Recent completely knotless constructs may lead to lesser clinical outcomes if the construct properties are compromised from lack of suture knots. Hypothesis A completely knotless construct without medial row knots will compromise the biomechanical properties in both cyclic and failure-testing parameters. Study Design Controlled laboratory study. Methods Six matched pairs of cadaveric shoulders were randomized to 2 groups of double row fixation with SutureBridge: group 1 with medial row knots, and group 2 without medial row knots. The specimens were placed in a materials test system at 30° of abduction. Cyclic testing to 180 N at 1 mm/sec for 30 cycles was performed, followed by tensile testing to failure at 1 mm/sec. Results Data included cyclic and failure data from the materials test system and gap data using a video digitizing system. All data from paired specimens were compared using paired Student t tests. Group 1 had a statistically significant difference (P < .05) for gap formation for the 1st (3.47 vs 5.05 mm) and 30th cycle (4.22 vs 8.10 mm) and at yield load (5.2 vs 9.1 mm). In addition, there was a greater energy absorbed (2805 vs 1648 N-mm), yield load (233 vs 183.1 N), and ultimate load (352.9 vs 253.9 N) for group 1. The mode of failure for the majority (4/6) of group 2 was lateral row failure, whereas all group 1 specimens failed at the clamp. Conclusion Although lateral row knotless fixation has been shown not to sacrifice structural integrity of this construct, the addition of a knotless medial row compromises the construct leading to greater gapping and failure at lower loads. Clinical Relevance This may raise concerns regarding recently marketed completely knotless double row constructs.

High-Tension Double-Row Footprint Repair Compared with Reduced-Tension Single-Row Repair for Massive Rotator Cuff Tears

Amassive, retracted tear of the rotator cuff poses a unique challenge to the orthopaedic surgeon. All attempts must be made to mobilize the tendons such that they can be repaired to their anatomic insertion sites on the greater tuberosity in a tension-free manner. However, many retracted tears cannot be fully mobilized. In this situation, there is substantial controversy over the most successful repair technique. The advent of double-row repairs has been a substantial advance in rotator cuff repair. The double-row technique has been shown to be biomechanically superior to single-row and transosseous suture techniques1-4. However, the studies comparing these repair constructs have subjected all specimens to the same loads, failing to account for differences in tension between the repair constructs. In the case of a retracted massive cuff tear that cannot be adequately mobilized, performing a double-row footprint repair as advocated by several authors requires repairing the cuff under tension1,4. For this reason, Snyder and others have advocated performing a medialized repair with a single-row technique5, which may allow for repair under reduced tension. Thus, controversy exists around the question of which approach is biomechanically superior: a double-row technique under tension at the footprint or a reduced-tension medialized repair with a single-row technique. The purpose of the present study was to compare the biomechanical behavior of these two approaches in a cadaver model accounting for differences in tension between the constructs. Our hypothesis was that the double-row footprint repair construct would demonstrate superior biomechanical properties in spite of being subjected to higher load conditions. ### Preliminary Data In order to compare the medial repair with the anatomic repair, it was necessary to determine the tension differential between the two sites. Hersche and Gerber studied long-standing ruptures of the supraspinatus and found a 45-N …

Arthroscopic debridement of glenoid labral tears in athletes

UNLABELLED This is a retrospective study of 46 patients who underwent arthroscopic glenoid labral debridement from June 1988 to June 1990. All patients complained of pain in the involved shoulder and all were active in sports involving overhead use of the shoulder, including 30 baseball players (16 professional, 14 collegiate/high school). The average age was 22 years (range 16 to 45) and the average follow-up was 2.7 years (range 18 to 50 months). At operation, 35 patients had posterior glenoid lesions, 9 had anterior-superior lesions, and 2 had anterior-inferior lesions. The posterior lesions were further divided into those that involved a horizontal flap tear (n = 19), and those that involved fraying (n = 16). Overall, at an average of 31 months follow-up. 54% (25 of 46) of patients had good to excellent results. Professional baseball players had a statistically significant enhanced outcome with 75% (12 of 16) good-excellent compared with the remaining nonprofessional group, with 43% (13 of 30) good-excellent results. Outcome did not correlate with shoulder laxity, labral lesion location, mechanism of injury, or the presence of a rotator cuff lesion. CONCLUSIONS Arthroscopic debridement of glenoid labral lesions does not yield consistent long-term results. Aggressive, supervised physical therapy in highly motivated individuals may be the most important factors in influencing outcome in patients having arthroscopic labral debridement in the absence of overt shoulder instability.