MR evaluation of factors predicting the development of rotator cuff tears

[Systematics of injuries of the rotator cuff and biceps tendon]

PERFORMANCE

Injuries of the rotator cuff and the biceps tendon demonstrate different patterns, which can be recognized clinically and radiologically.

ACHIEVEMENTS

These patterns are impingement syndrome with additional trauma, isolated trauma of the rotator cuff and shoulder dislocation causing rotator cuff tears. Furthermore, it is clinically crucial to evaluate the extent of a rotator cuff injury.

PRACTICAL RECOMMENDATION

Magnetic resonance imaging (MRI) is the modality of choice to differentiate these patterns.

Coracohumeral Distances and Correlation to Arm Rotation: An In Vivo 3-Dimensional Biplane Fluoroscopy Study

Background:

Reduced coracohumeral distances have been reported to be associated with anterior shoulder disorders such as subscapularis tears, biceps tendon injuries, and leading edge supraspinatus tears.

Purpose:

To determine the variability in coracohumeral distance as a function of arm rotation in healthy male subjects. The null hypothesis was that no differences in coracohumeral distance would exist with respect to arm rotation.

Study Design:

Descriptive laboratory study.

Methods:

A total of 9 male participants who had full range of motion, strength, and no prior surgery or symptoms in their tested shoulders were enrolled in this institutional review board–approved study. Computed tomography scans of the shoulder were obtained for each subject. A dynamic biplane fluoroscopy system recorded internal and external shoulder rotation with the arm held in the neutral position. Three-dimensional reconstructions of each motion were generated, and the coracohumeral distance and coracoid index (lateral extension of the coracoid) were measured.

Results:

The mean coracohumeral distance in neutral rotation was 12.7 ± 2.1 mm. A significantly shorter minimum coracohumeral distance of 10.6 ± 1.8 mm was achieved (P = .001) at a mean glenohumeral joint internal rotation angle of 36.6° ± 19.2°. This corresponded to a reduction in coracohumeral distance of 16.4% (range, 6.6%-29.8%). The mean coracoid index was 14.2 ± 6.8 mm. A moderate correlation (R = −0.75) existed between the coracohumeral distance and coracoid index.

Conclusion:

Coracohumeral distance was reduced during internal rotation. Decreased coracohumeral distance was correlated with larger coracoid indices.

Clinical Relevance:

This study provides a reference value for coracohumeral distance in the healthy male population. Knowledge of how coracohumeral distance varies over the range of arm internal-external rotation may improve the clinical diagnosis and treatment plan for patients with anterior shoulder pathology, specifically subcoracoid impingement. Imaging of the coracohumeral distance during internal rotation with the hand at approximately midline should be considered to assess patients with anterior shoulder pain.

Magnetic resonance imaging of rotator cuff disease and external impingement

Magnetic resonance (MR) imaging plays a major role in helping to identify rotator cuff disease and in demonstrating the pathology associated with external impingement. Many surgeons rely on MR imaging to assist in decision making and presurgical planning for patients with rotator cuff pain. This article reviews the etiology of external impingement and rotator cuff tears, and describes the MR imaging appearance of the normal and the pathologic rotator cuffs. It focuses on the supraspinatus tendon because this is the tendon involved in 95% of rotator cuff tears.

Shoulder impingement: relationship of clinical symptoms and imaging criteria

OBJECTIVE

To establish, in patients with subacromial impingement syndrome, (1) the relationship between pain and shoulder function, as determined by the Constant score, and morphological findings, as determined by radiographs and magnetic resonance imaging (MRI) and (2) the relationship between acromial shape and minimum acromiohumeral distance (AHD).

DESIGN

Cross-sectional study.

SETTING

Tertiary care center.

PATIENTS

Forty-seven patients (33 males and 14 females; mean age, 51.7 years) with unilateral subacromial impingement syndrome who had failed to respond to conservative therapy for at least 6 months.

INTERVENTIONS

The Constant score was determined preoperatively; acromial shape (type I, flat; type II, curved; and type III, hooked) was evaluated on preoperative outlet view radiographs and oblique sagittal T1-weighted MRIs; AHD was evaluated on preoperative anteroposterior radiographs and oblique coronal T1-weighted MRIs.

MAIN OUTCOME MEASURES

Correlation coefficients and the simple kappa statistic were calculated. Student t test and mean differences with 95% confidence limits were reported for group comparisons.

RESULTS

The Constant score was fairly correlated with AHD (r = 0.39, P < 0.01) but not with acromial shape. Patients with an AHD < or =7 mm on MRI scored significantly lower than those with an AHD >7 (mean difference, 18.5; P < 0.01). Acromial shape and AHD were not correlated, neither on radiographs nor on MRI.

CONCLUSIONS

AHD seems to better reflect the clinical status of patients with subacromial impingement, but without rotator cuff tears, than acromial shape. Acromial shape is not a good descriptor of subacromial space narrowing.

The acromiohumeral and coracohumeral intervals are abnormal in rotator cuff tears with muscular fatty degeneration

We sought to determine how various types of full-thickness rotator cuff tears, fatty degeneration of the rotator cuff muscles, duration of symptoms, and mechanism of injury affect the sizes of the acromiohumeral and coracohumeral intervals. We studied 206 shoulders with rotator cuff tears that had surgical treatment. The acromiohumeral interval (anteroposterior radiograph) and the coracohumeral interval (computed tomogram) were measured on preoperative imaging studies. An abnormal acromiohumeral interval was associated with multiple-tendon rotator cuff tears involving the infraspinatus, fatty degeneration of the supraspinatus or infraspinatus, and duration of symptoms longer than 5 years. An abnormal coracohumeral interval was associated with a combined tear of the supraspinatus and subscapularis and fatty degeneration of the infraspinatus or subscapularis. Fatty degeneration of the infraspinatus therefore was associated with an abnormal acromiohumeral interval and an abnormal coracohumeral interval. Evaluation of a patient who has a diminished acromiohumeral or coracohumeral interval should involve examination with computed tomography or magnetic resonance imaging of the rotator cuff tendons to determine the type of tear and of the rotator cuff muscles to determine the degree of fatty degeneration.

LEVEL OF EVIDENCE

Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients--with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

[Impingement syndrome of the shoulder]

The impingement syndrome is a clinical entity characterized by shoulder pain due to primary or secondary mechanical irritation of the rotator cuff. The primary factors for the development of impingement are a curved or hook-shaped anterior acromion as well as subacromial osteophytes, which may lead to tearing of the supraspinatus tendon. Secondary impingement is mainly caused by calcific tendinopathy, glenohumeral instability, os acromiale and degenerative changes of the acromioclavicular joint. Conventional radiographs are initially obtained, mainly for evaluation of the bony structures of the shoulder. If available, sonography can be used for detection of lesions and tears of the rotator cuff. Finally, MR-imaging provides detailed information about the relationship of the acromion and the acromioclavicular joint to the rotator cuff itself. In many cases however, no morphologic cause for impingement syndrome can be found. While patients are initially treated conservatively, chronic disease usually requires surgical intervention.

Clinically significant skeletal variations of the shoulder and the wrist: role of MR imaging

Several skeletal variations of the upper extremity may cause painful conditions or precipitate early degenerative changes, either spontaneously or in response to overuse and trauma. Magnetic resonance imaging has proved particularly useful for accurate interpretation of many of these clinically significant skeletal variations; however, the widespread use of MR imaging may have contributed to over-emphasizing their clinical importance, which is still controversial in many cases. We review, illustrate, and discuss clinically significant skeletal variations of the upper extremity as seen on MR images, particularly those involving the shoulder and the wrist. In the shoulder region, we evaluate variations of acromial and coracoid processes as well as variations and minor dysplastic deformities of the glenoid fossa. We also review different skeletal variations of the carpal region, including ulnar variance, ulnar styloid, lunate morphology, carpal coalition, and carpal accessory ossicles. The role of MR imaging in assessing the clinical importance of such conditions, whether potential, controversial, or well established, is emphasized in this review.

Evidence-Based Soft Tissue Rheumatology. Part I

Impingement into the coracoacromiohumeral space, a common cause of rotator cuff tendinopathy, may result from an impinging osteoligamentous upper boundary, abnormalities in the tendon itself, or failure of muscles that retain the humeral head on the glenoid. An overuse mechanism is clearly a risk factor in throwing athletes, whereas occupational overuse may contribute to its development in nonathletes. The subacromial anesthetic injection test remains as the acknowledged gold standard for diagnosis. There is evidence on the therapeutic efficacy of nonsteroidal antiinflammatory drugs, glucocorticoid subacromial injection, and acupuncture as compared with placebo. Also, acromioplasty appears to be better than physiotherapy. Patients with rotator cuff tendinopathy may be successfully treated with nonsteroidal antiinflammatory drugs, a glucocorticoid subacromial injection, or acupuncture. In failures of conservative therapy, surgery should be considered. Further research is required on etiology, diagnosis, natural course, and validity of many treatments currently used in this common condition.