Subcoracoid impingement and subscapularis tendon: is there any truth?

Shoulder Impingement Syndrome

Shoulder impingement is the most common diagnosis for shoulder pain. Shoulder impingement syndrome has been scrutinized as a misleading "umbrella" term, due to its vague and nonspecific context. It is better subcategorized into subacromial, internal, and subcoracoid impingement. The evaluation and treatment algorithm for each is grossly similar. A thorough history, focused physical examination, and standard radiographs are the first steps. Advanced imaging with MRI or ultrasound may be useful. The mainstay of treatment includes physical therapy, anti-inflammatory medications, and injections. Surgical treatment is reserved for refractory cases, and includes decompression, debridement, and/or repair of injured structures.

Biomechanical Analysis of Coracoid Stability After Coracoplasty: How Low Can You Go?

Background:

Arthroscopic coracoplasty is a procedure for patients affected by subcoracoid impingement. To date, there is no consensus on how much of the coracoid can be resected with an arthroscopic burr without compromising its stability.

Purpose:

To determine the maximum amount of the coracoid that can be resected during arthroscopic coracoplasty without leading to coracoid fracture or avulsion of the conjoint tendon during simulated activities of daily living (ADLs).

Study Design:

Controlled laboratory study.

Methods:

A biomechanical cadaveric study was performed with 24 shoulders (15 male, 9 female; mean age, 81 ± 7.9 years). Specimens were randomized into 3 treatment groups: group A (native coracoid), group B (3-mm coracoplasty), and group C (5-mm coracoplasty). Coracoid anatomic measurements were documented before and after coracoplasty. The scapula was potted, and a traction force was applied through the conjoint tendon. The stiffness and load to failure (LTF) were determined for each specimen.

Results:

The mean coracoid thicknesses in groups A through C were 7.2, 7.7, and 7.8 mm, respectively, and the mean LTFs were 428 ± 127, 284 ± 77, and 159 ± 87 N, respectively. Compared with specimens in group A, a significantly lower LTF was seen in specimens in group B (P = .022) and group C (P < .001). Postoperatively, coracoids with a thickness ≥4 mm were able to withstand ADLs.

Conclusion:

While even a 3-mm coracoplasty caused significant weakening of the coracoid, the individual failure loads were higher than those of the predicted ADLs. A critical value of 4 mm of coracoid thickness should be preserved to ensure the stability of the coracoid process.

Clinical Relevance:

In correspondence with the findings of this study, careful preoperative planning should be used to measure the maximum reasonable amount of coracoplasty to be performed. A postoperative coracoid thickness of 4 mm should remain.

Relationship between Radiological Measurement of Subcoracoid Impingement and Subscapularis Tendon Lesions

Background

The value of radiological measurements of subcoracoid impingement such as the coracohumeral interval in predicting subscapularis tendon injuries is controversial. We aimed to assess the relationship between radiological measurements of subcoracoid impingement and subscapularis tendon lesions in young and middle-aged adults.

Methods

This study was designed as a retrospective cohort study. Patients between the ages of 18–55 years without a history of shoulder surgery or major trauma were included and patients with arthritis, instability, or retracted rotator cuff tears were excluded from the study. Magnetic resonance images were evaluated and patients were grouped into two according to the subscapularis tendon condition: normal or pathologic. Glenoid version, axial coracohumeral distance, coracoglenoid angle, coracoid index, sagittal coracoid-glenoid tubercule distance, and axial coracoacromial inclination-glenoid version difference were measured for all patients. Measurement findings were compared between the groups. Correlation analysis was performed for age and radiologic measurements. A p < 0.05 was considered statistically significant for all tests.

Results

A total of 298 patients, 107 women (35.1%) and 191 men (64.9%), with a mean age of 34.46 ± 10.10 years (range, 18–55 years) were examined in the study. Subscapularis tendon pathology was noted in 85 patients (28.5%). The diagnosed pathologies were tendinosis in 48 patients (56.5%), partial tears in 28 (32.9%), and full thickness tears in 9 (10.6%). A significant relationship was observed between increasing age and subscapularis tendon lesions (p = 0.001). There was no statistically significant relationship between subscapularis pathology and calculated measurements. Axial coracohumeral distance and coracoglenoid angle measurements showed a statistically significantly negative correlation with age. A positive correlation was found between axial coracohumeral distance and coracoglenoid angle measurements (p < 0.001) and also between glenoid version and coracoid index measurements (p = 0.004). Axial coracohumeral distance and coracoglenoid angle measurements showed a negative correlation with glenoid version and coracoid index measurements (p < 0.05).

Conclusions

In this study, the coracohumeral distance and coracoglenoid angle decreased and the incidence of subscapularis tendon lesions increased as the age progressed. However, no relationship was found between radiological measurements and subscapularis tendon lesions.

The anterior translation of the humeral head leads to a decrease in the coracohumeral distance in subscapularis tear

A total of 297 patients who classified as subscapularis (SC) tears through arthroscopic evaluation were retrospectively enrolled, and Fifty-seven patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The coracohumeral distance (CHD) and humeral head anterior translation (HHAT) were measured on magnetic resonance imaging. Our study demonstrated that the anterior translation of the humeral head is related with a decrease in the coracohumeral distance in subscapularis tear. Although, correlation between radiologic parameters (coracohumeral distance and anterior translation of the humeral head) and severity of subscapularis tear was note detected.

Level of evidence

Level IV, retrospective study.

Surgical Outcomes after Arthroscopic Single Row Anchor Repair for Subscapularis Tears Concomitant with Injury of the Long Head of the Biceps Tendon

Objective

To analyze the clinical effects of single row anchor in repairing tears of the subscapularis muscle combined with the long head of the biceps tendon (LHBT) injury under arthroscopy.

Methods

From June 2016 to June 2017, the clinical data of 32 patients with subscapularis combined with biceps tendon injury were retrospectively analyzed. Preoperative MRI examination of the shoulder joint was performed to evaluate tendon injuries, and the subscapularis muscle was repaired with single row anchor under arthroscopy, and tenotomy or tenodesis was performed on the long head tendon of the biceps humerus in the intertubercular groove. The range of motion and the functional score of the shoulder joint before and after the operation were evaluated. All patients were followed up for at least 24 months.

Results

The mean follow‐up period was 28.8 months (range, 24–34 months). No infections occurred during the follow‐up period. The patients’ follow up exams showed significant improvement in postoperative shoulder joint flexion, external rotation, and internal rotation (P < 0.01), and the postoperative shoulder function American Society of Shoulder and Elbow Surgery Shoulder Joint Score (ASES; 80.6 ± 7.6) was significantly higher than the preoperative score (P < 0.01). The visual analog scale score (1.8 ± 0.8) was significantly lower than that before surgery (P < 0.01). The constant score (80.5 ± 7.4) was significantly higher than preoperation (P < 0.01). There was no significant difference in shoulder joint score between the tenotomy and tenodesis groups (P > 0.05). Preoperative and postoperative scores were, respectively: visual analog scale score (1.7 ± 0.9 vs 1.8 ± 0.0.8) ASES score (81.3 ± 7.9 vs 80.1 ± 8.0) and constant score (80.9 ± 8.0 vs 80.1 ± 6.9).

Conclusion

Using single row anchor under arthroscopy to repair subscapularis combined with long head of biceps tendon injury yielded good results and high tendon healing rates were obtained.

Predictors of safety margin for coracoid transfer: a cadaveric morphometric analysis

Background

The purpose of this study was to investigate the relationship between the bone length available for coracoid transfer without coracoclavicular ligament injury and the distance from the coracoid tip to the attachments of the coracoacromial ligament or pectoralis minor. We hypothesized that cadaver height and the soft tissue attachments on the coracoid process were predictive factors for sufficient bone length for coracoid transfer.

Methods

This study included 28 shoulders from Japanese cadavers: 19 male and 9 female. The distance from the coracoid tip to the distal attachment of the coracoclavicular ligament and the anterior and posterior margins of the coracoacromial ligament or pectoralis minor on the coracoid process were measured.

Results

The mean available length for coracoid transfer was 24.8 ± 3.4 mm. There was a significant difference in length between male and female subjects, being 26.0 ± 2.9 mm and 22.2 ± 3.0 mm, respectively (p = 0.004). High positive correlations were found between the length of the coracoid transfer and cadaver’s height (r = 0.48, p = 0.009) and the distance from the coracoid tip to the anterior coracoacromial ligament attachment (r = 0.63, p < 0.001). The receiver operating characteristic curve area under the curve for cadaver height was 0.72 while that for distance from coracoid tip to anterior coracoacromial ligament was 0.88 when predicted for a sufficient length for coracoid transfer > 25 mm.

Conclusions

Our findings will aid surgeons in preoperative planning and performing of osteotomy of the coracoid safely by predicting the available length of coracoid bone graft.

Anatomic Study of Subcoracoid Morphology in 418 Shoulders: Potential Implications for Subcoracoid Impingement

Background:

Subcoracoid impingement has been implicated as a cause of anterior shoulder pain and subscapularis tendon tears.

Purpose/Hypothesis:

The purpose of this study was to evaluate the bony anatomy of the coracoid process and the subcoracoid space. We hypothesized that age-related changes that may contribute to subcoracoid impingement occur in the subcoracoid space.

Study Design:

Descriptive laboratory study.

Methods:

In total, 418 skeletal shoulder specimens were included in this study. We utilized 214 shoulders from a young cohort (25-35 years of age) and 204 shoulders from an older cohort (>55 years of age) for comparison. We evaluated several morphological characteristics of the coracoid process and the subcoracoid space: coracoid width, coracoid shape, coracoid thickness, and subcoracoid distance. Each coracoid was observed for the presence of spurring or other morphological changes.

Results:

The mean anteroposterior (AP) thickness of the coracoid tip was 7.9 and 9.4 mm in our young female and male cohorts, respectively, while the mean AP thickness was 8.1 and 9.7 mm in our older female and male cohorts, respectively. The coracoid tip was hooked in 31 of 108 young female shoulders compared with 55 of 102 older female shoulders, and the coracoid tip was hooked in 25 of 106 young male shoulders compared with 45 of 102 older male shoulders. The mean subcoracoid distance in neutral rotation was 14.8 and 12.5 mm in young and older female shoulders, respectively, while the mean subcoracoid distance in internal rotation in these same cohorts was 8.7 and 7.0 mm, respectively. The mean subcoracoid distance in neutral rotation was 14.8 and 13.3 mm in young and older male shoulders, respectively, while the mean subcoracoid distance in internal rotation was 8.6 and 8.1 mm in young and older male shoulders, respectively.

Conclusion:

The principal findings of our study demonstrate that anatomic changes implicated in subcoracoid impingement may be developmental and worsen with age. The subcoracoid space was narrower in our older cohort of shoulders. Additionally, these older shoulders also had a greater AP width and a more hooked coracoid compared with young shoulders.

Clinical Relevance:

Narrowing of the subcoracoid space has been shown to be implicated as a cause of anterior shoulder pain and subscapularis tendon tears. This is the first study to show that the morphological changes implicated in subcoracoid impingement become more prevalent with age. This may help to explain the increasing prevalence of subscapularis tendon tears in older patients. Furthermore, subcoracoid decompression may be seen as an option for older patients with anterior shoulder pain and subscapularis tendon tears.

Coracoid Process: The Lighthouse of the Shoulder

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck. Surgeons often refer to the coracoid process as the "lighthouse of the shoulder" given its proximity to major neurovascular structures such as the brachial plexus and the axillary artery and vein, its role in guiding surgical approaches, and its utility as a landmark for other important structures in the shoulder. The coracoid also serves as a critical anchor for many tendinous and ligamentous attachments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and transverse scapular ligaments. Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions. This article will detail the anatomy of the coracoid and its associated structures and review the clinical and radiologic findings of corresponding pathologic conditions in this region with original illustrations and multimodality imaging examples. Highlighted in this article are the coracoclavicular joint, the classification and management of coracoid fractures, subcoracoid impingement, the coracoacromial arch and subacromial impingement, the coracohumeral ligament and the biceps pulley, the coracoclavicular ligament and its surgical reconstruction, adhesive capsulitis, the suprascapular notch and suprascapular notch impingement, subcoracoid bursitis, coracoid transfer procedures, and coracoid tumors. A brief summary of the pathophysiology, potential causes, and management options for each of the pathologic entities will also be discussed. ^©RSNA, 2016.

Sonographic Findings in Subcoracoid Impingement Syndrome: A Case Report and Literature Review

Subcoracoid impingement syndrome is a rare and underrecognized cause of anterior shoulder pain. Currently, subcoracoid impingement syndrome is understood to involve impingement of anatomic structures such as the subcoracoid bursa and subscapularis tendon within the coracohumeral space, and there are no reports of sonographic findings in subcoracoid impingement syndrome other than the impingement of thickened subscapularis bursa. Here we report a case of subcoracoid impingement syndrome, including a novel sonographic finding, arthroscopic findings, and a proposed pathophysiology.

LEVEL OF EVIDENCE

V.

The Coracohumeral Distance in Shoulders With Traumatic and Degenerative Subscapularis Tendon Tears

BACKGROUND

A reduced coracohumeral distance (CHD) is thought to be responsible for subcoracoid impingement. This only accounts for degenerative tendon tears. In traumatic tears, the subcoracoid space should be normal.

HYPOTHESIS

The CHD in patients with traumatic subscapularis tendon tears is larger than that in patients with degenerative tears and does not differ from patients with an intact subscapularis tendon.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 83 patients with arthroscopically certified subscapularis tendon tears were included in the study. Forty-four patients had degenerative causes (group 1), and 39 had traumatic causes (group 2). The control group consisted of 20 patients with traumatic supraspinatus tendon tears and arthroscopically proven, intact subscapularis tendons (group 3). On preoperative axial magnetic resonance imaging, the distance between the CHD was measured, and the values of the 3 groups were compared using the t test.

RESULTS

The mean (±SD) CHD in patients with degenerative subscapularis tendon tears was 8.6 ± 2.0 mm (range, 4.0-13.2 mm) and was significantly (P = .0003) smaller than that in patients with traumatic tears (10.2 ± 2.0 mm; range, 6.6-16.2 mm) or controls (10.4 ± 1.8 mm; range, 6.8-14.0 mm). The CHD of controls and patients with traumatic tears did not differ significantly (P = .7875). A CHD of less than 6 mm only occurred in patients with degenerative subscapularis tendon tears.

CONCLUSION

The hypothesis that the CHD in patients with degenerative subscapularis tendon tears is significantly smaller than that in patients with traumatic tears or intact subscapularis tendons was confirmed. The CHD in patients with traumatic tears does not differ from that in controls. A CHD of less than 6 mm only occurs in patients with degenerative subscapularis tendon tears.

Locations of lesser tuberosity cysts and their association with subscapularis, supraspinatus, and long head of the biceps tendon disorders

BACKGROUND

Humeral head cysts are not uncommon in individuals with rotator cuff disorders. The cysts are usually considered an indicator of rotator cuff pathologies; however, they may have different meanings in different regions.

PURPOSE

To determine the frequency of cysts within and adjacent to the lesser tuberosity and the relationship between these cysts and subscapularis, supraspinatus, and long head of the biceps tendon (LHBT) disorders.

MATERIAL AND METHODS

We retrospectively reviewed 760 consecutive shoulder magnetic resonance imaging (MRI) examinations. Among these MRIs, we selected a group of patients with cysts located around the lesser tuberosity. The study population was also divided into two subgroups, patients with cysts within the lesser tuberosity and those with cysts adjacent to the lesser tuberosity. In addition to the number and size of cysts, the MRI appearance of the tendons was evaluated.

RESULTS

Eighty-one (10.7%) patients had cysts within and/or adjacent to the lesser tuberosity, 34 (42%) patients had cysts within the lesser tuberosity, and 47 (58%) patients had cysts adjacent to it. LHBT and subscapularis tendon disorders were significantly related to more than one cyst. In a univariate analysis, cysts within the lesser tuberosity were significantly associated with LHBT and subscapularis tendon disorders; however, multivariate analyses showed that only LHBT disorders were significantly associated with cysts within the lesser tuberosity.

CONCLUSION

Cysts within the lesser tuberosity were less common than cysts adjacent to it. LHBT and subscapularis tendon disorders were more frequently found in patients with more than one cyst within and/or adjacent to the lesser tuberosity. In addition, cysts within the lesser tuberosity were associated with LHBT disorders.

Coracoacromial ligament section under ultrasonographic control: a cadaveric study on 20 cases

INTRODUCTION

The coracoacromial ligament is a complex anatomical structure involved in the development of subacromial impingement; treatment is founded on sectioning the ligament, with or without associated arthroscopic acromioplasty and debridement.

HYPOTHESIS

Complete coracoacromial ligament section can be performed under ultrasound, without lesion to surrounding structures.

MATERIALS AND METHODS

The coracoacromial ligament was sectioned on the coracoid side, under ultrasound navigation, in 10 cadavers donated to science: i.e. 20 shoulders. After ultrasound location of the shoulder structures, sectioning was performed with a skin incision at the level of the deltopectoral sulcus. Secondary surgical control checked conservation of the acromial branch of the thoracoacromial artery, and the quality of the procedure.

RESULTS

Mean surgery duration was 18.5 minutes (±5 min). Seventeen sections were complete (85%). Artery location was hampered by the impossibility of using Doppler on these cadavers, yet even so there were only 2 vascular lesions. There were no accidental rotator cuff or cartilaginous lesions.

CONCLUSION

This relatively non-invasive technique is quick and less heavy than open surgery, opening up new treatment perspectives. It could be indicated in coracoid and subacromial impingement before opting for surgery, or as a complement to surgery. It does, however, involve a learning curve and requires solid ultrasound skills.