Detection of acromioclavicular joint pathology in asymptomatic shoulders with magnetic resonance imaging

A comparison of magnetic resonance imaging findings of the acromioclavicular joint in symptomatic versus asymptomatic patients

The purpose of this study was to compare acromioclavicular (AC) joint magnetic resonance imaging (MRI) findings in asymptomatic patients with those in symptomatic patients. The MRI scans of 25 patients with symptomatic AC joints were compared with 50 asymptomatic control subjects by use of the same grading scale. In the symptomatic group, AC joint arthritis grading was normal in 0%, mild in 20%, moderate in 52%, and severe in 28%. In the asymptomatic group, grading was normal in 18%, mild in 66%, moderate in 12%, and severe in 4%; there was a statistically higher grade of AC arthritis in the symptomatic group (P < .05). Of the symptomatic individuals, 80% demonstrated reactive bone edema in either the distal clavicle (6), the acromion (3), or both sides of the AC joint (11), whereas no individual in the asymptomatic group had this finding (P < .05). Reactive bone edema on MRI is a more reliable predictor of symptomatic AC pathology than degenerative changes seen on MRI and, when correlated with clinical examination, is reproducible.

Visualization of Intraarticular Structures of the Acromioclavicular Joint in an Ex Vivo Model Using a Dedicated MRI Protocol

OBJECTIVE

The purpose of this study was to develop an MRI protocol that could visualize the intraarticular structures of the acromioclavicular (AC) joint.

MATERIALS AND METHODS

Using six fresh specimens from cadaveric shoulders, several MRI sequences were performed on 1.0-T scanners with a superficial coil (the temporomandibular joint coil). After the radiologic examination, the specimens were prepared for histology and 300-microm-thick, toluidine blue-stained sections were prepared that corresponded to the MR images. In each series of sections, immunohistochemistry using a type II collagen antibody was performed to further characterize the intraarticular structures.

RESULTS

The coronal 3D T1-weighted fast-field echo water-selective sequence allowed the identification of the intraarticular disk in all cases. Determination on MRI of other intraarticular structures--adipose tissue, synovial fluid, and the borders between neighboring tissues of different types--that corresponded to the histologic sections was possible. The use of a second plane in the 1.0-T sequences did not reveal additional information.

CONCLUSION

The described MRI protocol allows the visualization of the intraarticular fibrocartilaginous disk and the border between articular cartilage and the disk. Future clinical studies will indicate the diagnostic value of this protocol. We assume that this MRI protocol could help us to better understand AC joint disorders, in particular those located intraarticularly, and dislocations.

Diagnostic value of physical tests for isolated chronic acromioclavicular lesions

PURPOSE

Chronic acromioclavicular joint lesions are a common source of pain and disability in the shoulder. The goal of this study was to evaluate diagnostic values of physical tests for isolated, chronic acromioclavicular joint lesions.

STUDY DESIGN

A retrospective case-control study.

METHODS

Between 1994 and 2002, 35 patients underwent a distal clavicle excision for isolated acromioclavicular joint lesions. The results of 3 commonly used examinations for acromioclavicular joint lesions were calculated for sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy.

RESULTS

The cross body adduction stress test showed the greatest sensitivity (77%), followed by the acromioclavicular resisted extension test (72%) and active compression test (41%). The active compression test had the greatest specificity (95%). All tests had a negative predictive value of greater than 94%, but the positive predictive value was less than 30% for all tests. The active compression test had the highest overall accuracy (92%), followed by the acromioclavicular resisted extension test (84%) and the cross arm adduction stress test (79%). Combinations of the tests increased the diagnostic values for chronic acromioclavicular joint lesions.

CONCLUSIONS

These tests have utility in evaluating patients with acromioclavicular joint pathologic lesions, and a combination of these physical tests is more helpful than isolated tests.

Diagnostic values of tests for acromioclavicular joint pain

BACKGROUND

This prospective study was performed to determine which clinical and imaging tests were most helpful for diagnosing acromioclavicular joint pain.

METHODS

Of 1037 patients with shoulder pain, 113 who mapped pain within an area bounded by the midpart of the clavicle and the deltoid insertion were eligible for inclusion in the study. Forty-two subjects agreed to participate, and four of them were lost to follow-up. Twenty clinical tests, radiography, bone-scanning, magnetic resonance imaging, and an acromioclavicular joint injection test were performed on all patients. The patients were divided into two groups according to whether they had a > or =50% decrease in pain following the acromioclavicular joint injection. Statistical analysis, including multivariate regression analysis, was performed in order to evaluate the diagnostic effectiveness of the various tests.

RESULTS

Acromioclavicular joint pain was confirmed in twenty-eight of the thirty-eight patients. The most sensitive tests were examination for acromioclavicular tenderness (96% sensitivity), the Paxinos test (79%), magnetic resonance imaging (85%), and bone-scanning (82%), but these studies had low specificity. In the stepwise regression model, with the response to the injection used as the dependent variable, bone-scanning and the Paxinos test were the only independent variables retained. Patients with a positive Paxinos test as well as a positive bone scan had high post-test odds (55:1) and a 99% post-test probability of having pain due to pathological changes in the acromioclavicular joint. The likelihood ratio for patients with one negative test and one positive test was indeterminate (0.4:1). Patients with both a negative Paxinos test and a negative bone scan had a likelihood ratio of 0.03:1 for having acromioclavicular joint pain, which basically rules out the disorder.

CONCLUSIONS

The highly sensitive tests had low specificity, and the highly specific tests had low sensitivity. However, the combination of a positive Paxinos test and a positive bone scan predicted damage to the acromioclavicular joint as the cause of shoulder pain with a high degree of confidence.

Isolated Acromioclavicular Joint Pathology in the Symptomatic Shoulder on Magnetic Resonance Imaging

The acromioclavicular (AC) joint is a synovial joint that is predisposed to painful syndromes because of mechanical stress or developmental variation. It is often overlooked in the evaluation of patients with shoulder pain, however. Isolated AC joint pathology was studied on magnetic resonance imaging scans of patients with symptoms suggesting rotator cuff pathology. The conditions identified included osteoarthritis, distal clavicle osteolysis, and os acromiale syndrome.

MRI features of the acromioclavicular joint that predict pain relief from intraarticular injection

OBJECTIVE

Our objective was to evaluate the predictive value of various MRI findings in the acromioclavicular joint for pain relief after intraarticular injection.

MATERIALS AND METHODS

The acromioclavicular joint of 50 patients (20 women, 30 men; mean age, 51 years; range, 25-75 years) was evaluated on MRIs of the shoulder. Osteophytes, subchondral cysts and irregularities, bone marrow edema, joint effusion, and joint capsule hypertrophy were assessed by two musculoskeletal radiologists in consensus. Local anesthetics were injected into the acromioclavicular joint with fluoroscopic guidance. Patients graded pain relief on a visual analogue scale (0-100%) after 15 min. The relationship between pain relief and MRI findings was assessed with the Mann-Whitney U test. Pain relief equal to or greater than 70% was rated as a positive response to the injection. This cutoff value was used to calculate sensitivity, specificity, accuracy, and predictive values of the various MRI findings in determining which acromioclavicular joints were responsive to joint injections.

RESULTS

Mean pain relief after injection was 38%. Pain relief was significantly related to capsular hypertrophy (p = 0.007) and was equal to or greater than 70% in 11 patients. The sensitivity in diagnosing a successful injection (range, 9-82%) was highest for caudal osteophytes (82%) and capsular hypertrophy (73%). The specificity (range, 51-97%) was highest for subchondral cysts (97%), subchondral bone marrow edema (95%), and joint effusion (92%).

CONCLUSION

Pain relief after intraarticular injection is significantly related to capsular hypertrophy diagnosed on MRI. MRI findings have a reasonable sensitivity and a high specificity in predicting relevant short-term pain relief after intraarticular injection.