Can symptomatic acromioclavicular joints be differentiated from asymptomatic acromioclavicular joints on 3-T MR imaging?

Anatomical variants of the acromioclavicular joint influence its visibility in the standard MRI protocol in patients aged 18-31 years

Purpose

Visualization of a structure in orthogonal planes is essential for correct radiological assessment. The aim was to assess the utility of the standard MRI protocol for the shoulder in the assessment of the acromioclavicular joint (ACJ).

Methods

A total of 204 MRI scans of the shoulder were re-reviewed. Visibility of the ACJ in orthogonal planes was assessed, and the type of acromion and the angle between the ACJ and the glenoid cavity were assessed by two observers.

Results

Agreement in the assessment of ACJ visibility was moderate to substantial. The ACJ was visible in the three anatomical views in 48% (confidence interval [CI] 95% = [41–54%]) of the examinations, and no significant difference regarding gender or age was noticed. The mean angle between the ACJ and the glenoid cavity was 41.12 deg. CI95% = (39.72, 42.53) in the axial plane, 33.39 deg. CI95% = (31.33, 35.45) in the coronal plane and 52.49 deg. CI95% = (50.10, 54.86) in the sagittal plane. When the ACJ was visible in the sagittal and axial planes, significant differences were noticed in the remaining planes (p < .05).

Conclusion

Anatomical variations of the ACJ influence its visibility in the standard MRI protocol for examining the shoulder, making this protocol insufficient for ACJ assessment in the examined population.

Bony Edema and Clinical Examination Findings Predict the Need for Distal Clavicle Excision at the Time of Shoulder Arthroscopy

Background: Deciding to perform a distal clavicle excision for acromioclavicular joint arthritis, especially in conjunction with other arthroscopic shoulder procedures, is challenging for surgeons. Studies have reported mixed results on the value of magnetic resonance imaging (MRI) in decision making. Purpose: We sought to correlate MRI findings with clinical symptoms and the surgeon's decision to perform a distal clavicle excision. Methods: We compared MRI, clinical examination, and MRI findings of 200 patients who underwent distal clavicle excision for symptomatic acromioclavicular joint arthritis with 200 patients who underwent arthroscopic shoulder procedures for other reasons. Univariate statistics were used to determine correlations between physical examination findings, MRI findings, and the decision to perform distal clavicle excision. A binary logistic regression model was used to determine independent predictors of need for distal clavicle excision. Results: There was no difference in mean age, sex, and race between groups. Advanced acromioclavicular joint osteoarthritis was strongly correlated with positive physical examination findings. Bony edema correlated strongly with tenderness at the acromioclavicular joint but not pain with cross-body adduction testing. There was no association between higher MRI grade of osteoarthritis and the need for distal clavicle excision. Regression analysis identified both physical examination findings and bony edema on MRI as independent predictors of the need for distal clavicle excision. Conclusion: In the setting of positive clinical examination findings and bony edema of the distal clavicle, surgeons should feel reassured that distal clavicle excision is likely indicated.

Acromioclavicular Joint: What to Look for

Acromioclavicular joint (ACJ) pathology is a common source of shoulder girdle pain, frequently coexisting with and sharing overlapping clinical features of rotator cuff and glenohumeral articular lesions. ACJ trauma and osteoarthritis dominate clinical presentation; however, an array of pathologies can affect the joint. MR imaging of the ACJ is a powerful secondary diagnostic tool in early diagnosis of ACJ pathology and in accurate assessment of ACJ injuries, helping to resolve clinically challenging cases and allowing for individualized treatment planning. Knowledge of ACJ anatomy, biomechanics, and pathology is fundamental to interpreting and providing a clinically relevant ACJ MR imaging report.

Magnetic resonance imaging scans are not a reliable tool for predicting symptomatic acromioclavicular arthritis

BACKGROUND

We investigated whether magnetic resonance imaging (MRI) scans can accurately diagnose arthritis of the acromioclavicular joint (ACJ) because it has recently been suggested that bone marrow oedema on MRI scans is a predictive sign of symptomatic ACJ arthritis.

METHODS

The MRI scans of 43 patients (50 shoulders) who underwent ACJ excision for clinically symptomatic ACJ arthritis were compared to a control group of 43 age- and sex-matched patients (48 shoulders) who underwent an MRI scan for investigation of shoulder pain but did not have clinical symptoms or signs of ACJ arthritis. The scans were evaluated by an experienced musculoskeletal radiologist, who was blinded to the examination findings.

RESULTS

Bone marrow oedema was present in only 15 (30%) shoulders in the ACJ excision group, although this was higher than the six shoulders in the asymptomatic group (p = 0.03). Forty-one (82%) shoulders in the symptomatic group had grade III/IV ACJ arthritis compared to 31 (65%) in the asymptomatic group (p = 0.05). However, 44 out of 48 (92%) shoulders in the asymptomatic group had signs of osteoarthritis on MRI scans.

CONCLUSIONS

In contrast to recent reports, the present study shows that MRI is not helpful in making the diagnosis of ACJ arthritis. A focused history and clinical examination should remain the mainstay for surgical decision making.

LEVEL OF EVIDENCE

Level 3.

Predictive findings on magnetic resonance imaging in patients with symptomatic acromioclavicular osteoarthritis

BACKGROUND

A magnetic resonance imaging (MRI) scan of the shoulder can have added value in diagnosing symptomatic osteoarthritis of the acromioclavicular (AC) joint. Specific MRI signs have been recognized but not analyzed extensively before. This study aims to identify predictive MRI signs in patients with symptomatic AC osteoarthritis.

METHODS

The MRI scans of 70 patients with symptomatic AC osteoarthritis were compared with those of 70 patients with subacromial pain syndrome and no clinical signs of symptomatic AC osteoarthritis. Seven variables were evaluated on the MRI scans of the AC joint: joint space narrowing, inferior osteophytes, joint effusion, osteolysis, bone marrow edema, impression on the supraspinatus, and inferior joint distension. Logistic regression analysis of these variables was performed.

RESULTS

The presence of inferior osteophytes, bone marrow edema, impression on the supraspinatus, and inferior joint distension was individually associated with symptomatic AC osteoarthritis. Bone marrow edema was observed only in patients with symptomatic AC osteoarthritis. Multivariate analysis showed a significant association between inferior joint distension, as well as impression on the supraspinatus muscle, and symptomatic AC osteoarthritis. The area under the receiver operating characteristic curve in the multivariate logistic model was 0.839 (95% confidence interval, 0.771 to 0.907). Interobserver and intraobserver variability showed good to excellent κ values (range, 0.68 to 0.88).

CONCLUSION

We identified predictive MRI signs in patients with symptomatic AC osteoarthritis. These findings, including bone marrow edema, inferior joint distension, and impression on the supraspinatus muscle, showed good discriminative ability. They are practical and easy to use and can assist the physician in diagnosing symptomatic AC osteoarthritis.

Osseous spurs at the fovea capitis femoris-a frequent finding in asymptomatic volunteers

OBJECTIVE

To investigate the different morphologic types of the fovea capitis femoris and the spectrum of osseous spurs/osteophytes of the fovea in asymptomatic volunteers and patients with hip osteoarthritis.

MATERIAL AND METHODS

Sixty-five patients (mean age 63.6 years) with radiographically confirmed osteoarthritis of the hip and 59 asymptomatic healthy volunteers (mean age 33.9 years) underwent non-contrast MRI of the hip joint. Two radiologists independently evaluated all images. Fovea morphology (standard type, diamond type, flat type, triangular type) as well as the frequency, size and location of spurs/osteophytes of the fovea were assessed. Descriptive and inferential statistics were applied.

RESULTS

The most frequent morphologic type of the fovea capitis femoris was the standard type for both asymptomatic volunteers (average 45%) and patients (average 49%). Osseous spurs were detected in 70% of the asymptomatic volunteers, and 97% of the patients had osteophytes. Spur size at all locations was significantly smaller in asymptomatic volunteers (range 1-2 mm) than osteophyte size in patients (range 1-4 mm) (p ≤ 0.035). In volunteers and patients, the spurs/osteophytes were most frequently located at the anterior border of the fovea capitis femoris.

CONCLUSION

Smaller osseous spurs (<2 mm) at the border of the fovea capitis femoris are very common in asymptomatic volunteers and do not seem to be pathologic.