Sonographic assessment of subacromial bursa distension during arm abduction: establishing a threshold value in the diagnosis of subacromial impingement syndrome

Bilateral ultrasonographic findings in patients with unilateral subacromial pain syndrome and intact rotator cuff tendons

BACKGROUND

The etiology of subacromial pain syndrome (SAPS) remains enigmatic. It is theorized that the supraspinatus tendon and the subacromial bursa are the primary pain-generating structures. The supraspinatus tendon and the subacromial bursa are considered to be thickened in patients with SAPS but this assumption lacks validation. The aim of this study was to ultrasonographically measure the subacromial structures and evaluate the presence of impingement in patients with SAPS and to compare it with their asymptomatic shoulder.

METHODS

Patients were recruited consecutively from an orthopedic outpatient clinic using validated criteria for SAPS. Patients with contralateral shoulder pain and patients with acromioclavicular osteoarthrosis, rotator cuff tears, calcified tendinopathy, biceps tendon, or labral pathology were excluded. Validated ultrasonographical methods were used. Thickness of the supraspinatus tendon and the subacromial bursa were measured perpendicular to the tendon longitudinal axis 2.0 cm from the lateral border of the supraspinatus tendon footprint with the shoulder in slight internal rotation. Acromio-humeral distance was measured as the shortest distance from the anterolateral acromion to the humerus with the shoulder in neutral position. Ultrasonographic impingement was defined as visual bulging of the subacromial bursa during active shoulder abduction and internal rotation.

RESULTS

We examined 58 patients with unilateral SAPS and intact rotator cuff tendons. We found significantly more cases of ultrasonographic impingement in painful shoulders compared to the pain-free (45 vs. 18, Chi-Square P < .001). There were no significant differences between affected and unaffected shoulders regarding supraspinatus tendon thickness (5.4 vs. 5.5 mm), subacromial bursa thickness (1.9 vs. 1.9 mm), or the acromio-humeral distance (11.1 vs. 11.0 mm). The mean age of the included patients was 51 years, 64% were women, the median symptom duration was 18 months, and the dominant shoulder was affected in 71% of cases.

CONCLUSION

In this cohort of patients with isolated unilateral SAPS, we found more cases of ultrasonographic impingement in affected shoulders compared to unaffected, but no significant differences in supraspinatus tendon thickness, subacromial bursa thickness, or acromio-humeral distance. These findings question ultrasonography's ability to discriminate between shoulders with and without SAPS based on measurements of subacromial structures alone.

Prevalence and mechanisms of subacromial impingement in breast cancer patients after breast-conserving surgery and radiation therapy: a case-cohort study

PURPOSE

Subacromial impingement is a painful shoulder disorder, which may be common after breast cancer treatment. A previous study showed a high prevalence after mastectomy but prevalence after conservatively treated patients is unknown. Impingement mechanisms in breast cancer survivors have not been studied.

METHODS

Twenty-four breast cancer survivors who had undergone breast-conserving surgery without axillary lymph node dissection followed by radiation therapy, and 12 cancer-free controls were included. Breast cancer survivors were grouped by the presence of subacromial impingement pain. The subacromial space and the supraspinatus tendon were imaged using ultrasound on the treated side in the breast cancer survivors and a randomly chosen side in controls. In these images, the width of the subacromial space, thickness of the supraspinatus tendon and combined thickness of the supraspinatus tendon and surrounding soft tissues were measured.

RESULTS

Subacromial impingement prevalence among breast cancer survivors was 54%. The width of the subacromial space and the thickness of the supraspinatus tendon were not different in breast cancer survivors with subacromial impingement compared to breast cancer survivors without subacromial impingement and controls. Combined thickness of the supraspinatus tendon and surrounding soft tissues was grater in breast cancer survivors with subacromial impingement.

CONCLUSION

Prevalence of subacromial impingement is high, even in the most conservatively treated breast cancer patients. The presence of subacromial impingement pain is unrelated to width of the subacromial space, but greater thickness of the supraspinatus tendon and surrounding soft tissue may be part of the impingement mechanism.

ACR Appropriateness Criteria® Chronic Shoulder Pain: 2022 Update

Chronic shoulder pain is an extremely common presenting complaint. Potential pain generators include the rotator cuff tendons, biceps tendon, labrum, glenohumeral articular cartilage, acromioclavicular joint, bones, suprascapular and axillary nerves, and the joint capsule/synovium. Radiographs are typically the initial imaging study obtained in patients with chronic shoulder pain. Further imaging may often be required, with modality chosen based on patient symptoms and physical examination findings, which may lead the clinician to suspect a specific pain generator. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Interobserver agreement on the sonographic severity grading of shoulder impingement syndrome

BACKGROUND

Shoulder impingement syndrome is the painful entrapment of the soft tissues between the acromion and the humeral head. The severity of shoulder impingement could be graded according to the limitation of shoulder joint moment. The reliability of sonographic findings in the grading of shoulder impingement severity grading is required to be evaluated by the consistency of findings between the observers.

PURPOSE

To assess the interobserver agreement in the sonographic severity grading of shoulder impingement syndrome with the help of a ratio between acromion-to-greater tuberosity distance in the abduction and neutral arm position.

MATERIAL AND METHODS

Patients were examined by two independent observers in the coronal approach with neutral arm position. Acromion-to-greater tuberosity distance was measured in abduction and neutral shoulder position. The ratios of the distances in the abduction and neutral position were calculated to grade the severity of shoulder impingement syndrome.

RESULTS

A total of 78 shoulders were included in this study. A strong agreement was found for the grading of shoulder impingement severity grading between the two independent observers with Kappa value of 0.94. And correlation between the results of the two observers for the severity grading of shoulder impingement syndrome was significant at 0.01 level.

CONCLUSION

Severity grading of the shoulder impingement syndrome was performed based on the ratio of acromion-to-greater tuberosity distance in abduction and neutral arm position. However, the sonographic findings were consistent and a strong interobserver agreement was seen in this sonographic severity grading.

Ultrasonographic Technique, Appearance, and Diagnostic Accuracy for Common Shoulder Sports Injuries: A Narrative Review

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Ultrasonography (US) is valued for its availability, tolerability, low cost, and utility in real-time dynamic evaluation. Its use in diagnosing upper-extremity shoulder injury has expanded, but several features require definition before more widespread adoption can be realized.

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In particular, the evaluation of rotator cuff tears (RCTs) with US has been extensively studied, and authors generally agree that US is comparable with magnetic resonance imaging for the detection of full-thickness RCTs, whereas partial-thickness RCTs are more difficult to accurately identify with US. Dynamic evaluation is particularly useful for pathologies such as subacromial impingement and glenohumeral instability.

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US has shown particular usefulness for the assessment of athletes, where there is additional motivation to delay more invasive techniques. US has demonstrated promising results as a diagnostic modality for common shoulder injuries in athletes, and it is an important imaging tool that complements a thorough history and physical examination.