The Thrower's Shoulder

Overhead athletes have comparable intraoperative injury patterns and clinical outcomes to non-overhead athletes following surgical stabilization for first-time anterior shoulder instability at average 6-year follow-up

BACKGROUND AND HYPOTHESIS

Anterior shoulder instability is a common problem affecting young, athletic populations that results in potential career-altering functional limitations. However, little is known regarding the differences in clinical outcomes after operative management of overhead vs. non-overhead athletes presenting with first-time anterior shoulder instability. We hypothesized that overhead athletes would have milder clinical presentations, similar surgical characteristics, and diminished postoperative outcomes when compared with non-overhead athletes after surgical stabilization following first-time anterior shoulder instability episodes.

METHODS

Patients with first-time anterior shoulder instability events (subluxations and dislocations) undergoing operative management between 2013 and 2020 were included. The exclusion criteria included multiple dislocations and multidirectional shoulder instability. Baseline demographic characteristics, imaging data, examination findings, and intraoperative findings were retrospectively collected. Patients were contacted to collect postoperative patient-reported outcomes including American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index score, Brophy activity index score, and Subjective Shoulder Value, in addition to return-to-work and -sport, recurrent dislocation, and revision rates.

RESULTS

A total of 256 patients met the inclusion criteria, of whom 178 (70%) were non-overhead athletes. The mean age of the entire population was 23.1 years. There was no significant difference in concomitant shoulder pathology, preoperative range of motion, or preoperative strength between cohorts. A greater proportion of overhead athletes presented with instability events not requiring manual reduction (defined as subluxations; 64.1% vs. 50.6%; P < .001) and underwent arthroscopic surgery (97% vs. 76%, P < .001) compared with non-overhead athletes. A smaller proportion of overhead athletes underwent open soft-tissue stabilization compared with non-overhead athletes (1% vs. 19%, P < .001). Outcome data were available for 60 patients with an average follow-up period of 6.7 years. No significant differences were found between groups with respect to recurrent postoperative instability event rate (13.0% for overhead athletes vs. 16.8% for non-overhead athletes), revision rate (13.0% for overhead athletes vs. 11.1% for non-overhead athletes), American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index score, Brophy score, Subjective Shoulder Value, or rates of return to work or sport.

CONCLUSION

Overhead athletes who underwent surgery after an initial instability event were more likely to present with subluxations compared with non-overhead athletes. With limited follow-up subject to biases, this study found no differences in recurrence or revision rates, postoperative patient-reported outcomes, or return-to-work or -sport rates between overhead and non-overhead athletes undergoing shoulder stabilization surgery following first-time instability events. Although larger prospective studies are necessary to draw firmer conclusions, the findings of this study suggest that overhead athletes can be considered in the same treatment pathway for first-time dislocation as non-overhead athletes.

Initial Assessment and Management of Select Musculoskeletal Injuries: A Team Physician Consensus Statement

ABSTRACT

Musculoskeletal injuries occur frequently in sport during practice, training, and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury-A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference, an annual project-based alliance of six major professional associations. The goal of this document is to help the team physician improve the care and treatment of the athlete by understanding the initial assessment and management of selected musculoskeletal injuries.

Initial Assessment and Management of Select Musculoskeletal Injuries: A Team Physician Consensus Statement

ABSTRACT

Musculoskeletal injuries occur frequently in sport during practice, training, and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury-A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference, an annual project-based alliance of six major professional associations. The goal of this document is to help the team physician improve the care and treatment of the athlete by understanding the initial assessment and management of selected musculoskeletal injuries.

Is Workload Associated With Internal Impingement in Professional Baseball Pitchers? An Analysis of Days of Rest, Innings Pitched, and Batters Faced

Background

Internal impingement is a common cause of shoulder pain and dysfunction in baseball pitchers.

Purpose/Hypothesis

The purpose of this study was to determine if the amount of rest days between outings, the number of innings pitched in each outing, and the number of batters faced in each outing are risk factors for internal impingement in professional baseball pitchers. It was hypothesized that a higher workload would significantly increase a pitcher's risk of developing internal impingement.

Study Design

Case-control study; Level of evidence, 3.

Methods

All professional (Major and Minor League) baseball pitchers who were diagnosed with internal impingement between 2011 and 2017 were identified using the Major League Baseball's Health and Injury Tracking System. A separate player usage data set was used to determine workload. The authors compared workload variables (days of rest, innings pitched, and batters faced per game) between each of 4 injury-exposure groups (pitchers with documented internal impingement <2, <6, <12, and >12 weeks after a game) and a control group of pitchers with no internal impingement using Student t tests or Mann-Whitney U tests. In a within-pitcher paired analysis of the injury groups, the workload variables during 3 acute periods (<2, <6, and <12 weeks preinjury) were compared with the baseline values (>12 weeks preinjury).

Results

Overall, there were 624 professional baseball pitchers diagnosed with internal impingement during the study period. Compared with pitcher games (n = 213,964), pitchers in all 4 injury-exposure groups had significantly more innings pitched per game (P ≤ .003 for all) and faced significantly more batters per game (P < .001 for all). There were significantly more starting pitchers in each of the injury-exposure groups when compared with the controls (P < .001 for all). However, when comparing acute and baseline workloads in the pitchers diagnosed with internal impingement, there were no significant differences in the number of innings pitched, batters faced, or days of rest.

Conclusion

This analysis revealed significantly greater pitcher workload and percentage of starting pitchers in professional baseball players diagnosed with internal impingement when compared with healthy controls. However, this injury did not seem to be associated with an acute increase in workload.

Is early trunk rotation really hazardous for shoulder biomechanics in baseball throwing?

BACKGROUND AND HYPOTHESIS

Early trunk rotation (ETR), which is a unique kinematics of the trunk that occurs during baseball throwing, is thought to be related to shoulder injuries. Pelvic rotation is a confounder when studying the effects of trunk rotation on shoulder biomechanics. The purpose of this study was to understand the "pure" effects of trunk rotation on shoulder biomechanics, with pelvic rotation under control. Our hypotheses were as follows: (1) throwers with ETR have a different shoulder kinematics pattern compared with throwers without ETR; (2) throwers with ETR have a lower ball speed performance than do throwers without ETR; and (3) throwers with ETR have a greater value of shoulder forces and moments, which may increase risks of shoulder injury, than do throwers without ETR.

METHODS

Fifty-seven elite throwers were enrolled and divided into 2 groups (non-ETR and ETR) using an outdoor motion analysis. Several kinematics and kinetics parameters of the shoulder were analyzed and compared between the 2 groups.

RESULTS

Ball velocity was faster in the non-ETR group (127 km/h) compared with the ETR group (120 km/h). The shoulders of throwers in the ETR group showed pathokinematics of "horizontal adduction lag" and "dropped elbow." The increases in maximal posterior force, inferior force, horizontal abduction moment, and vertical adduction moment were 9.2%, 13.6%, 21.3%, and 24.3%, respectively, in the shoulders of throwers in the ETR group. These results indicate that ETR may be hazardous for the throwing shoulder. With lower ball velocity and higher shoulder joint loading, ETR is not a proper pitching pattern for kinetic energy transfer.

CONCLUSION

Improper pitching mechanics among baseball throwers, such as ETR, may result in higher shoulder joint loading and increased risk of shoulder injuries. When treating throwers with shoulder injuries, it is important not only to address shoulder anatomy and pathology but also to understand the possible pathomechanics and pathogenesis of the shoulder caused by ETR. Furthermore, special training programs focusing on trunk flexibility and core muscle strengthening should be implemented to prevent ETR and decrease the risk of shoulder injuries. Motion analysis is useful for the screening and early detection of improper pitching mechanics in throwers.

Disabled Throwing Shoulder: 2021 Update: Part 2-Pathomechanics and Treatment

The purpose of this paper is to provide updated information for sports healthcare specialists regarding the disabled throwing shoulder (DTS). A panel of experts, recognized for their experience and expertise in this field, was assembled to address and provide updated information on several topics that have been identified as key areas in creating the DTS spectrum. Each panel member submitted a concise presentation on one of the topics within these areas, each of which were then edited and sent back to the group for their comments and consensus agreement in each area. Part two presents the following consensus conclusions and summary findings regarding pathomechanics and treatment, including (1) internal impingement results from a combination of scapular protraction and humeral head translation; (2) the clinically significant labral injury that represents pathoanatomy can occur at any position around the glenoid, with posterior injuries most common; (3) meticulous history and physical examination, with a thorough kinetic chain assessment, is necessary to comprehensively identify all the factors in the DTS and clinically significant labral injury; (4) surgical treatment should be carefully performed, with specific indications and techniques incorporating low profile implants posterior to the biceps that avoid capsular constraint; (5) rehabilitation should correct all kinetic chain deficits while also developing high-functioning, throwing-specific motor patterns and proper distribution of loads and forces across all joints during throwing; and (6) injury risk modification must focus on individualized athlete workload to avoid overuse. LEVEL OF EVIDENCE: V, expert opinion.

Disabled Throwing Shoulder 2021 Update: Part 1-Anatomy and Mechanics

The purpose of this article is to provide updated information for sports health care specialists regarding the Disabled Throwing Shoulder (DTS). A panel of experts, recognized for their experience and expertise in this field, was assembled to address and provide updated information on several topics that have been identified as key areas in creating the DTS spectrum. Each panel member submitted a concise presentation on one of the topics within these areas, each of which were then edited and sent back to the group for their comments and consensus agreement in each area. Part 1 presents the following consensus conclusions and summary findings regarding anatomy and mechanics, including: 1) The current understanding of the DTS identifies internal impingement, resulting from a combination of causative factors, as the final common pathway for the great majority of the labral pathoanatomy; 2) intact labral anatomy is pivotal for glenohumeral stability, but its structure does not control or adapt well to shear or translational loads; 3) the biceps plays an active role in dynamic glenohumeral stability by potentiating "concavity compression" of the glenohumeral joint; 4) the ultimate function of the kinetic chain is to optimize the launch window, the precise biomechanical time, and position for ball release to most effectively allow the ball to be thrown with maximum speed and accuracy, and kinetic chain function is most efficient when stride length is optimized; 5) overhead throwing athletes demonstrate adaptive bony, capsular, and muscular changes in the shoulder with repetitive throwing, and precise measurement of shoulder range of motion in internal rotation, external rotation, and external rotation with forearm pronation is essential to identify harmful and/or progressive deficits. LEVEL OF EVIDENCE: Level V, expert opinion.

Three-Dimensional Upper Body Kinematics and Inter-articular Kinematic Sequence During a Canoe Polo Throw

Canoe polo is an increasingly popular discipline requiring both kayaking and ball-handling skills. While the kinematics of the upper body during throw has been investigated for several overhead sports, the canoe polo throw has still to be studied. Therefore, the aim of this study is to analyze the canoe polo throw kinematics in terms of angles and inter-articular sequencing to understand its specificity. A secondary aim was to investigate whether adding pelvis mobility has an impact. Nineteen male players of canoe polo were equipped with reflective body markers for the throw analysis. They performed 5 throws with the pelvis fixed and 5 throws with additional pelvic mobility in rotation around a vertical axis. Inverse kinematics was performed with OpenSim providing pelvis, trunk, and glenohumeral rotations. Angular velocities were calculated to build the inter-articular sequences relative to these throws. Statistical parametric mapping was used to assess the effect of pelvis mobility on the throwing kinematics. Similar kinematics patterns as in other overhead sports were observed, however, a different inter-articular sequence was found for the canoe polo throw with a maximal angular velocity occurring sooner for the thorax in axial rotation than for the pelvis in rotation. While the limitation of rotation of the pelvis around a vertical axis has an influence on the pelvis and trunk kinematics, it did not modify the kinematic sequence.

Evaluation of glenohumeral range of motion and humeral retroversion at ages after major change and differences in wrestlers

PURPOSE

This study aimed to present the change in humeral retroversion (HR) angle (HRA) that occurs in childhood and young adulthood and the potential developmental difference that is observed in wrestlers.

METHODS

HRA of dominant and non-dominant shoulders (DSHRA and NDSHRA, respectively) were measured using ultrasonography in a group of 30 wrestlers who started wrestling before the age of 13 years (Group 1), a group of 30 young adults, aged between 16-20 years, who were not actively engaged in any branch of overhead sports (Group 2) and a group of children aged between 11-13 years and not actively engaged in any branch of overhead sports (Group 3). Range of motion (ROM) degrees of dominant and non-dominant shoulders in all groups were compared within each group and between the groups.

RESULTS

DSHRA (mean: 88.73°, 88.93° and 89.40°) values were significantly higher than NDSHRA (mean: 81.13°, 81.83° and 84.37°) values (p < 0.001, p < 0.001 and p < 0,05) in Groups I, II and III, respectively. Internal rotation and total ROM degrees of the dominant shoulder in Group 1 and 3 were higher than those in Group 2.

CONCLUSION

There is no significant change in terms of HRA in people aged between 11-13 and 16-20 years because of natural development or wrestling. DSHRA values are higher than NDSHRA ones. In contrast to the shoulders of throwers, the shoulders of wrestlers are characterized by an increase in internal rotation, described as "Wrestler's shoulder."

LEVEL OF EVIDENCE

Level III.

Shoulder ranges of motion and humeral torsions of injured baseball players have different characteristics depending on their pitching sides

Background

Right- and left-side throwers in baseball may have different shoulder conditions and throwing biomechanics. This study aimed to compare the passive range of motion, humeral torsion, and clinical findings between right- and left-handed throwers who sustained throwing shoulder injuries and confirm the differences in the characteristics between throwing sides.

Methods

A total of 52 pitchers diagnosed with throwing shoulder injuries were included in this study: 27 patients were right-side throwers (R group), and 25 were left-side throwers (L group). We measured the bilateral passive external and internal rotation angles in abduction position (ABIR) and total arc at their first visit. To assess posterior shoulder tightness, the internal rotation angles in forward flexion (FIR), and the abduction angle (AA) and horizontal flexion angle (HFA) without scapula motion were measured. The bilateral humeral torsion angles were also measured using ultrasonography. These values were compared between the participants' throwing and non-throwing sides and between the R and L groups' throwing sides. Furthermore, several physical findings in the shoulders were assessed, and the positive ratio was compared between the R and L groups.

Results

On comparing the throwing and non-throwing sides, the R group had significantly greater external rotation angles in the abduction position and humeral torsion angle, and smaller ABIR, total arc, FIR, AA, and HFA in the throwing side, while the L group showed no significant differences, except for a smaller ABIR and larger HFA in the throwing side. On comparing the throwing side between the R and L groups, the R group had a smaller FIR, AA, and FHA than the L group. Regarding the physical findings, the posterior jerk test, Kim test, anterior and posterior drawer sign, sulcus sign, and scapular winging in the L group were significantly more positive than in the R group.

Conclusion

The range of motion and humeral torsions differed between the left- and right-side throwers, as did the pathology between their throwing sides. Clinicians should consider the possibility that the pathological condition differs between left- and right-side throwers.

Risk Factors for Revision Posterior Shoulder Stabilization in Throwing Athletes

Background

Revision posterior shoulder capsulolabral repair has inferior outcomes compared with primary surgery. Risk factors for revision in throwing athletes are unknown.

Purpose/Hypothesis

The purpose of this study was to characterize the revision rate and risk factors for revision surgery in throwing athletes. It was hypothesized that female athletes and those with smaller glenoid bone width would be at higher risk for revision surgery.

Study Design

Case-control study; Level of evidence, 3.

Methods

A total of 105 throwing athletes who underwent arthroscopic posterior capsulolabral repair of their throwing shoulder were reviewed at a minimum of 2-year follow-up, and patients who required a revision were compared with those who did not. Collected data compared between the revision and no-revision groups included age, sex, contact sport participation, and return to sport (RTS). American Shoulder and Elbow Surgeons (ASES) score, Kerlan-Jobe Orthopaedic Clinic (KJOC) score, stability, pain, strength, range of motion (ROM), and patient satisfaction. Radiographic parameters including glenoid bone version, cartilage version, labral version, bone width, labral width, glenoid labral version and width weight were also compared between both groups.

Results

Nine throwers required revision (8.6%) at an average of 2.8 years postoperatively. There were more female athletes in the revision than no-revision group (55.5% vs 23.4%; P = .03). There was no significant difference in age, proportion of contact athletes, rotator cuff tears, glenoid bone version, cartilage version, labral version, labral version weight, bone width, labral width, or labral width weight. Both groups had similar preoperative, postoperative, and change in ASES, KJOC, pain, strength, stability, and ROM scores. The proportion of patients with full strength and with full ROM, as well as patients who were satisfied with outcomes was similar between groups. Fewer patients in the revision group returned to sports compared with those in the no-revision group (14.3% vs 83.6%; P < .001), although return to sports at same level was not significantly different between groups (14.3% vs 37.2%; P = .41).

Conclusion

The revision rate of arthroscopic posterior shoulder stabilization in throwers was 8.6%. Female athletes were at higher risk for revision, and return to sports was lower in patients who underwent revision surgery.

The association between pelvic asymmetry and non-specific chronic low back pain as assessed by the global postural system

BACKGROUND

Empirical evidence that demonstrates the relationship between pelvic asymmetry and non-specific chronic low back pain (NCLBP) is currently lacking.

OBJECTIVE

To establish the reliability of the Global Postural System (GPS) in assessing pelvic asymmetry and identify the association between pelvic asymmetry parameters and the occurrence of NCLBP in young adults.

DESIGN

A cross-sectional, regression study.

METHODS

People who were aged between 18 and 30 and were diagnosed with NCLBP were recruited. Healthy individuals who were matched for age, sex, and education level were recruited as controls. Global Postural System (GPS) was employed to assess pelvic asymmetry. Prior to exploring the association, the reliability of GPS was assessed by the ICC (2, k) for interrater reliability, ICC (3, k) for intra-rater reliability, standard error and minimal detectable difference. Bivariate correlation analysis and logistic regression analysis were used to determine the relationship between pelvic asymmetry and the occurrence of NCLBP.

RESULTS

Twenty-eight healthy participants and 28 people with NCLBP were recruited. Moderate to excellent ICCs were observed for the inter-rater and intra-rater reliability of most postural parameters. The bivariate correlation analysis indicated that age, body mass index and pelvic asymmetry parameters were related to the occurrence of NCLBP. Pelvic angle asymmetry (odds ratio = 1.17), and asymmetry of the distance between the posterior superior iliac spine and the floor (odds ratio = 1.21) were associated with NCLBP.

LIMITATIONS

This study did not explore the causal relationship between pelvic asymmetry in the sagittal plane/pelvic asymmetry in the transverse plane and the occurrence of NCLBP. The interpretation of the results may not be generalized beyond the sample population.

CONCLUSIONS

The GPS is a reliable method to assess pelvic asymmetry in a clinical setting. Two pelvic parameters were associated with the presence of NLBP. Measurement of pelvic asymmetry may assist in the early identification of potential occurrence of NCLBP but further work is required.

In situ repair of partial-thickness rotator cuff tears: a critical analysis review

After failed conservative management, operative intervention is typically indicated for patients with partial-thickness rotator cuff tears (PTRCTs) with persistent pain and disability symptoms.

For PTRCTs involving < 50% of the tendon thickness, debridement with or without acromioplasty resulted in favourable outcomes in most studies.

For PTRCTs involving > 50% of the tendon thickness, in situ repair has proven to significantly improve pain and functional outcomes for articular and bursal PTRCTs.

The few available comparative studies in the literature showed similar functional and structural outcomes between in situ repair and repair after conversion to full-thickness tear for PTRCTs.

Most non-overhead athletes return to sports at the same level as previous to the injury after in situ repair of PTRCTs. However, rates of return to preinjury level of competition for overhead athletes have been generally poor regardless of the utilized technique.

During long-term follow-up, arthroscopic in situ repair of articular and bursal PTRCTs produced excellent functional outcomes in most patients, with a low rate of revision.

Cite this article: EFORT Open Rev 2020;5:138-144. DOI: 10.1302/2058-5241.5.190010