A stabilizing role of the glenoid labrum: the suction cup effect

Prevalence of abnormal ultrasonography findings in the posterosuperior humeral head of asymptomatic collegiate baseball pitchers

BACKGROUND

The posterosuperior humeral head contacts the glenoid during pitching. While magnetic resonance imaging often detects abnormalities in the posterosuperior humeral head of baseball pitchers, ultrasonography may also be effective in identifying these abnormalities. However, studies on such abnormalities in asymptomatic players are limited. Thus, this study aimed to determine the prevalence of abnormal findings in the humeral head using ultrasonography in asymptomatic collegiate baseball pitchers.

METHODS

We utilized ultrasonography to assess abnormal findings in the humeral head, defined as a break in continuity or an irregular surface around the infraspinatus insertion, in 33 college baseball pitchers (pitcher group) and 30 college students without experience in overhead sports (control group). For 11 of the 33 pitchers, computed tomography-like images were used to locate the abnormalities. The location was quantitatively identified in the axial plane using a clock system, with the bicipital groove designated as 12 o'clock, and qualitatively assessed in the sagittal plane. Shoulder internal and external rotation ranges of motion (IR and ER ROMs) and humeral retroversion were measured using an inclinometer. The prevalence of abnormalities among the 4 subgroups (throwing and nonthrowing shoulders of the pitcher group and dominant and nondominant shoulders of the control group) was compared using the Fisher's exact test. A paired t-test was also performed to compare the IR and ER ROMs, as well as the humeral retroversion between each group's throwing (dominant) and nonthrowing (nondominant) sides.

RESULTS

The prevalence of abnormalities was significantly higher (76%) in the throwing shoulder of the pitcher group than in the other shoulder groups (<.001). The mean position of the humeral head abnormalities in the axial plane was 8:32 ± 0:21 in the clock system, with all abnormalities located at the infraspinatus insertion on the greater tuberosity in the sagittal plane according to CT-like image analysis. While ER ROM and humeral retroversion were greater in the throwing shoulder, IR ROM was less than that in the non-throwing shoulder in the pitcher group (<.001).

CONCLUSION

Ultrasonographic assessments revealed a higher prevalence of abnormalities in humeral head for asymptomatic collegiate baseball pitchers. Repetitive throwing motions may lead not only to adaptations in the ROM of the shoulder joint but also to abnormalities in the humeral head. Thus, ultrasonography may help identify asymptomatic baseball players with physiological internal impingement.

Anterior Shoulder Instability: Pre- and Postoperative Imaging

Treatment algorithms for anterior glenohumeral instability are evolving. Identification of soft tissue injuries remains important because stand-alone labrum and ligament repairs are a mainstay of primary intervention. Increasingly recognized is the importance of bone lesions, particularly the synergistic effects of bipolar bone loss in the glenoid track model. Accordingly, reporting and measurement of bone lesions is crucial to treatment planning, especially in patients with a failed Bankart repair. This review covers (1) anatomy related to anterior shoulder instability, (2) preoperative imaging assessment of soft tissue injuries, (3) postoperative imaging assessment of soft tissue injuries, (4) imaging techniques for soft tissue injuries, (5) preoperative imaging of bone injuries, and (6) postoperative imaging of bone injuries.

Clinical Outcomes and Recurrence Rates After Arthroscopic Soft Tissue Stabilization With Selective Augmentations for Traumatic Anterior Shoulder Instability in Athletes Versus Non-athletes With Subcritical Glenoid Bone Loss

Introduction Although some studies have reported good outcomes of soft tissue procedures in athletes, to our knowledge, no study has directly compared the clinical outcomes and recurrence rates of soft tissue procedures between athletes and non-athletes. Therefore, we aimed to compare clinical outcomes and recurrence rates between athletes and non-athletes with subcritical glenoid bone defects, who received arthroscopic soft tissue stabilization surgery for traumatic anterior shoulder instability. Methods This retrospective comparative study included patients who received primary arthroscopic shoulder stabilization surgery for traumatic anterior shoulder instability, with a minimum two-year follow-up and a glenoid bone defect <20%. The patients were categorized into athlete or non-athlete groups. For the included patients, we performed one of the following procedures: arthroscopic Bankart repair (ABR), ABR with Hill-Sachs remplissage (HSR), or arthroscopic bony Bankart repair (ABBR). We investigated patient characteristics, including preoperative glenoid and humeral head pathology, and compared the two groups in terms of the Korean Shoulder Score for Instability (KSSI), University of California Los Angeles (UCLA) score, Rowe score, and range of motion (ROM) at two years postoperatively. Postoperative recurrence and reoperation rates were also compared. Results Altogether, 39 non-athletes and 15 athletes were included. Significantly higher KSSI (athletes: 98.00; non-athletes: 94.64; p = 0.012) was observed in the athletes than in the non-athletes. Meanwhile, the UCLA (athletes: 34.33; non-athletes: 33.87; p = 0.370) and Rowe (athletes: 96.67; non-athletes: 96.67; p = 0.460) scores were not significantly different between the two groups. Five (13%) non-athletes and one (7%) athlete experienced postoperative instability recurrence, which was not significantly different (p = 1.000). Fourteen (93%) athletes returned to sports completely after 5.4 months (range, 4-8 months) on average. Conclusion Arthroscopic soft tissue stabilization surgery yielded good clinical outcomes and low recurrence rates in both athletes and non-athletes with subcritical glenoid bone defects.

Comparison of Glenoid Bone Loss After Unidirectional Versus Combined Shoulder Instability in a Military Population

Background

While glenoid bone loss (GBL) after anterior shoulder instability correlates with poor functional outcomes, the specific effects of GBL in posterior and combined-type shoulder instability remain poorly characterized, especially in a high-risk military population.

Purpose/Hypothesis

The purpose of this study was to compare GBL between unidirectional anterior or posterior instability versus combined-type instability in active-duty servicemembers. It was hypothesized that total GBL and GBL in the direction of instability would be greater in those with combined-type instability compared with unidirectional instability.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Active-duty servicemembers who underwent shoulder stabilization surgery between January 2010 and December 2019 were eligible for inclusion. Patients with multidirectional instability, concomitant rotator cuff tears, osteochondritis dissecans of the glenoid or humeral head, superior labral anterior-posterior tears, biceps pathologies, and humeral avulsion of the glenohumeral ligament were excluded. Patients were grouped according to direction of instability (anterior, posterior, or combined), and patient characteristics, instability characteristics, suture anchor use, and GBL were compared between the 3 cohorts.

Results

In total, 117 patients met the study inclusion criteria. The mean patient age was 29 years, 89.7% were male, the dominant extremity was involved in 63.2%, 65.8% attributed their injuries to a singular traumatic event, and the mean follow-up was 7.9 years. There was no significant difference regarding patient characteristics, injury mechanism, or follow-up time between the 3 cohorts. As compared with the combined-type instability cohort, mean anterior GBL was greater in the anterior instability cohort (8.00% ± 4.40% vs 4.98% ± 5.26% for combined; P = .012), while mean posterior GBL was greater in the posterior instability cohort (7.44% ± 4.54% vs 4.86% ± 5.69% for combined; P = .024). There was no significant difference in mean total GBL between the combined-type (9.84% ± 7.82%) and either of the unidirectional cohorts (anterior: 8.00% ± 4.40% [P = .231]; posterior: 7.44% ± 4.54% [P = .082]).

Conclusion

GBL in the direction of instability was found to be significantly greater in the unidirectional versus combined-type instability cohorts.

Management of the in-season athlete with an anterior shoulder dislocation

BACKGROUND

Management of the in-season athlete presenting with an anterior shoulder dislocation is a nuanced process that continues to be refined. Options and pathways between nonoperative and operative treatment have undergone many iterations over a century of orthopedic research and advancement. It requires an understanding of sport-specific demands and the individual athlete's goals. The orthopedic surgeon must have mastery of the natural history, treatment options, and outcomes of anterior shoulder dislocations. Balance of these factors is delicate and highly individualized for each athlete, and is why management of the in-season athlete with an anterior shoulder dislocation remains an art for the orthopedic surgeon.

MATERIALS AND METHODS

A narrative review of the literature regarding the in-season athlete with anterior shoulder dislocation was conducted of the PubMed, Embase, and Cochrane databases. The findings are summarized in this article.

RESULTS

Multiple studies have investigated management of the in-season athlete with anterior shoulder dislocation. Treatment is highly individualized for each athlete and their respective circumstances. Nonoperative treatment remains the only option for athletes that seek to return to play in the same season, however with a high risk of recurrence. Operative treatment has a track record of success in terms of returning to high level of play and lower recurrence, but would preclude a return to competition in the same season.

CONCLUSIONS

Management of the in-season athlete with anterior shoulder dislocation remains a challenging issue without consensus recommendation among shoulder surgeons. Much has been done to understand the pathology and delineate indications for nonoperative treatment and surgical management. Although recurrence and return to play rates have improved with each iteration, recurrent instability and revision surgery continue to occur at high rates. Therefore, additional work remains to optimize return to play as well as long-term outcomes for athletes.

Biomechanics and Pathoanatomy of Posterior Shoulder Instability

Posterior glenohumeral instability represents a wide spectrum of pathoanatomic processes. A key consideration is the interplay between the posterior capsulolabral complex and the osseous anatomy of the glenoid and humeral head. Stability is dependent upon both the presence of soft tissue pathology (eg, tears to the posteroinferior labrum or posterior band of the inferior glenohumeral ligament, glenoid bone loss, reverse Hill Sachs lesions, and pathologic glenoid retroversion or dysplasia) and dynamic stabilizing forces. This review highlights unique pathoanatomic features of posterior shoulder instability and associated biomechanics that may exist in patients with posterior glenohumeral instability.

Radiographic and Advanced Imaging Evaluation of Posterior Shoulder Instability

PURPOSE OF REVIEW

Posterior shoulder instability is an uncommon but important cause of shoulder dysfunction and pain which may occur as the result of seizure, high energy trauma, or repetitive stress related to occupational or sport-specific activities. This current review details the imaging approach to the patient with posterior shoulder instability and describes commonly associated soft tissue and bony pathologies identified by radiographs, CT, and MR imaging.

RECENT FINDINGS

Advances in MR imaging technology and techniques allow for more accurate evaluation of bone and soft tissue pathology associated with posterior shoulder instability while sparing patients exposure to radiation. Imaging can contribute significantly to the clinical management of patients with posterior shoulder instability by demonstrating the extent of associated injuries and identifying predisposing anatomic conditions. Radiologic evaluation should be guided by clinical history and physical examination, beginning with radiographs followed by CT and/or MRI for assessment of osseous and soft tissue pathology. Synthesis of a patient's clinical history, physical exam findings, and radiologic examinations should guide clinical management.

Editorial Commentary: Anterior Shoulder Stabilization Combining Arthroscopic Bankart and Inferior Capsular Shift Avoids Open Surgery in Athletes Without Critical Glenoid Bone Loss

Traumatic anterior shoulder dislocations can cause a myriad of injuries, each with their own unique set of challenges with respect to surgical management. The debate of whether open or arthroscopic management is the superior approach is one that predates most currently practicing orthopaedic surgeons yet remains one of the most actively researched areas of orthopaedics. Current trends favor arthroscopic management for anterior instability secondary to a Bankart lesion in patients without other risk factors for instability, such as critical glenoid bone loss. However, excellent results are not guaranteed following arthroscopic Bankart repair, particularly in athletes, due to high rates of recurrence. While the technique of inferior to superior capsular shift is not new, transitioning a historically open technique to the arthroscopic world may represent another tool in the glenohumeral instability management toolbox. While perspectives are evolving, more evidence supporting arthroscopic techniques like the capsular shift are needed to better identify appropriate patient populations.

Concomitant Biceps Tenodesis Does Not Portend Inferior Outcomes After Anterior Glenohumeral Stabilization

BACKGROUND

Military patients are known to suffer disproportionately high rates of glenohumeral instability as well as superior labrum anterior to posterior (SLAP) tears. Additionally, a concomitant SLAP tear is frequently observed in patients with anterior shoulder instability. Even though biceps tenodesis has been demonstrated to produce superior outcomes to SLAP repair in military patients with isolated SLAP lesions, no existing studies have reported on outcomes after simultaneous tenodesis and anterior labral repair in patients with co-existing abnormalities.

PURPOSE

To evaluate outcomes after simultaneous arthroscopic-assisted subpectoral biceps tenodesis and anterior labral repair in military patients younger than 40 years. We also sought to compare these outcomes with those after repair of an isolated anterior labral tear.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study is a retrospective analysis of all military patients younger than 40 years from a single base who underwent arthroscopic anterior glenohumeral stabilization with or without concomitant biceps tenodesis between January 2010 and December 2019. Patients with glenoid bone loss of >13.5% were not eligible for inclusion. Outcome measures including the visual analog scale (VAS) for pain, the Single Assessment Numeric Evaluation (SANE), the American Shoulder and Elbow Surgeons (ASES) shoulder score, the Rowe instability score, and range of motion were administered preoperatively and postoperatively, and scores were compared between groups.

RESULTS

A total of 82 patients met inclusion criteria for the study. All patients were active-duty service members at the time of surgery. The mean follow-up was 87.75 ± 27.05 months in the repair + tenodesis group and 94.07 ± 28.72 months in the isolated repair group (P = .3085). Patients who underwent repair + tenodesis had significantly worse preoperative VAS pain (6.85 ± 1.86 vs 5.02 ± 2.07, respectively; P < .001), ASES (51.78 ± 11.89 vs 62.43 ± 12.35, respectively; P = .0002), and Rowe (26.75 ± 7.81 vs 37.26 ± 14.91, respectively; P = .0002) scores than patients who underwent isolated repair. Both groups experienced significant improvements in outcome scores postoperatively (P < .0001 for all), and there were no statistically significant differences in postoperative outcome scores or range of motion between groups. There were no differences in the percentage of patients who achieved the minimal clinically important difference, substantial clinical benefit, and patient acceptable symptom state for the VAS pain, SANE, ASES, and Rowe scores between groups. Overall, 37 of the 40 (92.50%) patients in the repair + tenodesis group and 40 of the 42 (95.24%) patients in the isolated repair group returned to unrestricted active-duty military service (P = .6045). In addition, 38 (95.00%) patients in the repair + tenodesis group and 40 (95.24%) patients in the isolated repair group returned to preinjury levels of sporting activity (P = .9600). There were no significant differences in the number of failures, revision surgical procedures, or patients discharged from the military between groups (P = .9421, P = .9400, and P = .6045, respectively).

CONCLUSION

The findings of this study indicate that simultaneous biceps tenodesis and labral repair was a viable treatment option for the management of concomitant SLAP and anterior labral lesions in young, active military patients younger than 40 years.