Kevin E. Wilk

Current Concepts in the Rehabilitation of the Overhead Throwing Athlete

The overhead throwing motion is an extremely skillful and intricate movement that is very stressful on the shoulder joint complex. The overhead throwing athlete places extraordinary demands on this complex. Excessively high stresses are applied to the shoulder joint because of the tremendous forces generated by the thrower. The throwers shoulder must be lax enough to allow excessive external rotation, but stable enough to prevent symptomatic humeral head subluxations, thus requiring a delicate balance between mobility and functional stability. We refer to this as the “throwers paradox.” This balance is frequently compromised, which leads to injury. Numerous types of injuries may occur to the surrounding tissues during overhead throwing. Frequently, injuries can be successfully treated with a well-structured and carefully implemented nonoperative rehabilitation program. The key to successful nonoperative treatment is a thorough clinical examination and accurate diagnosis. Athletes often exhibit numerous adaptive changes that develop from the repetitive microtraumatic stresses observed during overhead throwing. Treatment should focus on the restoration of these adaptations during the rehabilitation program. In this article, the typical musculoskeletal profile of the overhead thrower and various rehabilitation programs for specific injuries are discussed. Rehabilitation follows a structured, multiphase approach with emphasis on controlling inflammation, restoring muscle balance, improving soft tissue flexibility, enhancing proprioception and neuromuscular control, and efficiently returning the athlete to competitive throwing.

Biomechanics of the knee during closed kinetic chain and open kinetic chain . exercises

PURPOSE Although closed (CKCE) and open (OKCE) kinetic chain exercises are used in athletic training and clinical environments, few studies have compared knee joint biomechanics while these exercises are performed dynamically. The purpose of this study was to quantify knee forces and muscle activity in CKCE (squat and leg press) and OKCE (knee extension). METHODS Ten male subjects performed three repetitions of each exercise at their 12-repetition maximum. Kinematic, kinetic, and electromyographic data were calculated using video cameras (60 Hz), force transducers (960 Hz), and EMG (960 Hz). Mathematical muscle modeling and optimization techniques were employed to estimate internal muscle forces. RESULTS Overall, the squat generated approximately twice as much hamstring activity as the leg press and knee extensions. Quadriceps muscle activity was greatest in CKCE when the knee was near full flexion and in OKCE when the knee was near full extension. OKCE produced more rectus femoris activity while CKCE produced more vasti muscle activity. Tibiofemoral compressive force was greatest in CKCE near full flexion and in OKCE near full extension. Peak tension in the posterior cruciate ligament was approximately twice as great in CKCE, and increased with knee flexion. Tension in the anterior cruciate ligament was present only in OKCE, and occurred near full extension. Patellofemoral compressive force was greatest in CKCE near full flexion and in the mid-range of the knee extending phase in OKCE. CONCLUSION An understanding of these results can help in choosing appropriate exercises for rehabilitation and training.

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°, 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° or external rotation in the scapular plane between shoulders, and no difference in internal rotation at 90°, total motion, or laxity. A comparison of the dominant shoulders of the two groups indicated that both external rotation at 90° and humeral head retroversion were significantly greater in the throwing group.

A COMPARISON OF TIBIOFEMORAL JOINT FORCES AND ELECTROMYOGRAPHIC ACTIVITY DURING OPEN AND CLOSED KINETIC CHAIN EXERCISES

We chose to investigate tibiofemoral joint kinetics (compressive force, anteroposterior shear force, and extension torque) and electromyographic activity of the quadriceps, hamstring, and gastrocnemius muscles during open kinetic chain knee extension and closed kinetic chain leg press and squat. Ten uninjured male subjects performed 4 isotonic repetitions with a 12 repetition maximal weight for each exercise. Tib iofemoral forces were calculated using electromyo graphic, kinematic, and kinetic data. During the squat, the maximal compressive force was 6139 ± 1708 N, occurring at 91° of knee flexion; whereas the maximal compressive force for the knee extension exercise was 4598 ± 2546 N (at 90° knee flexion). During the closed kinetic chain exercises, a posterior shear force (poste rior cruciate ligament stress) occurred throughout the range of motion, with the peak occurring from 85° to 105° of knee flexion. An anterior shear force (anterior cruciate ligament stress) was noted during open kinetic chain knee extension from 40° to full extension; a peak force of 248 ± 259 N was noted at 14° of knee flexion. Electromyographic data indicated greater hamstring and quadriceps muscle co-contraction during the squat compared with the other two exercises. During the leg press, the quadriceps muscle electromyographic activ ity was approximately 39% to 52% of maximal velocity isometric contraction; whereas hamstring muscle ac tivity was minimal (12% maximal velocity isometric contraction). This study demonstrated significant differ ences in tibiofemoral forces and muscle activity be tween the two closed kinetic chain exercises, and be tween the open and closed kinetic chain exercises.

Operative Treatment of Ulnar Collateral Ligament Injuries of the Elbow in Athletes

Over a 6-year period, the senior author (JRA) performed 91 ulnar collateral ligament reconstructions (N 78) or repairs (N 13). All patients were male and between the ages of 15 and 39 years (average, 21.6). Thirty-seven patients (41%) were professional baseball players, 41 (45%) were collegiate baseball players, and 7 (7.7%) were high school or recreational players. Subcutaneous ulnar nerve transposition with stabilization of the nerve with fascial slings of the flexor pronator mass was performed in all patients, and additional procedures were performed in 27 patients (29.7%), including 22 excisions of posteromedial olecranon osteophytes. Average follow-up was 35.4 months. Ten patients had preoperative ulnar nerve symptoms, nine of whom had complete resolution of symptoms after surgery. Complications occurred in eight patients. The average time from surgery to initiation of the interval throwing program was 3.4 months, and the average time to return to competitive throwing was 9.8 months. Sixty-seven patients (74%) were available for follow-up; of these, 53 (79%) had returned to their previous levels of competition or to a higher level. Reconstruction of the ulnar collateral ligament, with transposition and stabilization of the ulnar nerve and appropriate rehabilitation, was found to be effective in correcting medial instability of the elbow and allowed most athletes to return to previous levels of play in less than 1 year.

Correlation of Glenohumeral Internal Rotation Deficit and Total Rotational Motion to Shoulder Injuries in Professional Baseball Pitchers

Background: Glenohumeral internal rotation deficit (GIRD) indicates a 20° or greater loss of internal rotation of the throwing shoulder compared with the nondominant shoulder. Purpose: To determine whether GIRD and a deficit in total rotational motion (external rotation + internal rotation) compared with the nonthrowing shoulder correlate with shoulder injuries in professional baseball pitchers. Study Design: Case series; Level of evidence, 4. Methods: Over 3 competitive seasons (2005 to 2007), passive range of motion measurements were evaluated on the dominant and nondominant shoulders for 170 pitcher-seasons. This included 122 professional pitchers during the 3 seasons of data collection, in which some pitchers were measured during multiple seasons. Ranges of motion were measured with a bubble goniometer during the preseason, by the same examiner each year. External and internal rotation of the glenohumeral joint was assessed with the participant supine and the arm abducted 90° in the plane of the scapula, with the scapula stabilized anteriorly at the coracoid process. The reproducibility of the test methods had an intraclass correlation coefficient of .81. Days in which the player was unable to participate because of injury or surgery were recorded during the season by the medical staff of the team and defined as an injury. Results: Pitchers with GIRD (n = 40) were nearly twice as likely to be injured as those without but without statistical significance (P = .17). Pitchers with total rotational motion deficit greater than 5° had a higher rate of injury. Minor league pitchers were more likely than major league pitchers to be injured. However, when players were injured, major league pitchers missed a significantly greater number of games than minor league pitchers. Conclusion: Compared with pitchers without GIRD, pitchers with GIRD appear to be at a higher risk for injury and shoulder surgery.

Outcome of Ulnar Collateral Ligament Reconstruction of the Elbow in 1281 Athletes: Results in 743 Athletes with Minimum 2-Year Follow-up

Background The anterior bundle of the ulnar collateral ligament (UCL) is the primary anatomical structure providing elbow stability in overhead sports, particularly baseball. Injury to the UCL in overhead athletes often leads to symptomatic valgus instability that requires surgical treatment. Hypothesis Ulnar collateral ligament reconstruction with a free tendon graft, known as Tommy John surgery, will allow return to the same competitive level of sports participation in the majority of athletes. Study Design Case series; Level of evidence, 4. Methods Ulnar collateral reconstruction (1266) or repair (15) was performed in 1281 patients over a 19-year period (1988—2006) using a modification of the Jobe technique. Data were collected prospectively and patients were surveyed retrospectively with a telephone questionnaire to determine outcomes and return to performance at a minimum of 2 years after surgery. Results Nine hundred forty-two patients were available for a minimum 2-year follow-up (average, 38.4 months; range, 24-130 months). Seven hundred forty-three patients (79%) were contacted for follow-up evaluation and/or completed a questionnaire at an average of 37 months postoperatively. Six hundred seventeen patients (83%) returned to the previous level of competition or higher, including 610 (83%) after reconstruction. The average time from surgery to the initiation of throwing was 4.4 months (range, 2.8-12 months) and the average time to full competition was 11.6 months (range, 3-72 months) after reconstruction. Complications occurred in 148 patients (20%), including 16% considered minor and 4% considered major. Conclusion Ulnar collateral ligament reconstruction with subcutaneous ulnar nerve transposition was found to be effective in correcting valgus elbow instability in the overhead athlete and allowed most athletes (83%) to return to previous or higher level of competition in less than 1 year.

The strength characteristics of internal and external rotator muscles in professional baseball pitchers

The purpose of this study was to establish a data base regarding the isokinetic muscular performance charac teristics of the external/internal rotator muscles of professional baseball pitchers. One hundred fifty healthy professional baseball pitchers were evaluated by use of a Biodex isokinetic dynamometer. The sub jects tested had a mean age of 23.4 years and a mean body weight of 199 pounds. Isokinetic tests were per formed concentrically at 180 and 300 deg/sec for both the throwing and nonthrowing shoulders. Testing pro cedures regarding positioning and stabilization followed established guidelines. The testing protocol and actual test repetitions were standardized for each subject. Statistical analysis was performed using the Pearson Product Moment Correlation and paired t-tests. Deter mination of the correlation coefficient was made at the P < 0.05 level of significance. Test results for bilateral comparison of mean peak torque for the throwing and nonthrowing shoulders indicated no statistically significant difference between the internal rotators at both test speeds, or for the external rotators at 300 deg/sec. There was a signifi cant statistical difference at the 180 deg/sec test speed for the external rotators. The external/internal rotator strength ratio indicated a 65% ratio at 180 deg/sec and a 61 % ratio at 300 deg/sec. Data were also collected for mean peak torque/body weight ratios of the throw ing shoulder to establish a data base in professional throwers. This study offers clinical relevance in establishing a muscle performance profile for the professional thrower. This data base can therefore be used as criteria that should be met before an injured pitcher can be returned to throwing at the professional baseball level.

Current Concepts in the Scientific and Clinical Rationale Behind Exercises for Glenohumeral and Scapulothoracic Musculature

SYNOPSIS The biomechanical analysis of rehabilitation exercises has led to more scientifically based rehabilitation programs. Several investigators have sought to quantify the biomechanics and electromyographic data of common rehabilitation exercises in an attempt to fully understand their clinical indications and usefulness. Furthermore, the effect of pathology on normal shoulder biomechanics has been documented. It is important to consider the anatomical, biomechanical, and clinical implications when designing exercise programs. The purpose of this paper is to provide the clinician with a thorough overview of the availableliterature relevant to develop safe, effective, and appropriate exercise programs for injury rehabilitation and prevention of the glenohumeral and scapulothoracic joints. LEVEL OF EVIDENCE Level 5.

Changes in shoulder and elbow passive range of motion after pitching in professional baseball players.

Background The overhead throwing athlete has unique range of motion characteristics of the shoulder and elbow. Numerous theories exist to explain these characteristics; however, the precise cause is not known. Although it is accepted that range of Motion is altered, the acute effect of baseball pitching on shoulder and elbow range of motion has not been established. Hypothesis There will be a reduction in passive range of motion immediately after baseball pitching. Study Design Controlled laboratory study. Methods Sixty-seven asymptomatic male professional baseball pitchers participated in the study. Passive range of motion Measurements were recorded using a customized bubble goniometer for shoulder external rotation, shoulder internal rotation, total shoulder rotational motion, elbow flexion, and elbow extension on the dominant and nondominant arms. Testing was performed on the first day of spring training. Measurements were taken before, immediately after, and 24 hours after pitching. Results A significant decrease in shoulder internal rotation (−9.5°), total motion (−10.7°), and elbow extension (−3.2°) occurred immediately after baseball pitching in the dominant shoulder (P < .001). These changes continued to exist 24 hours after pitching. No differences were noted on the nondominant side. Conclusion Passive range of motion is significantly decreased immediately after baseball pitching. This decrease in range of motion continues to be present 24 hours after throwing. High levels of eccentric muscle activity have previously been observed in the shoulder external rotators and elbow flexors during pitching. These eccentric muscle contractions may contribute to acute musculotendinous adaptations and altered range of motion. The results of this study may suggest a newly defined mechanism to range of motion adaptations in the overhead throwing athlete resulting from acute musculoskeletal adaptations, in addition to Potential osseous and capsular adaptations.