MR imaging of shoulder instability injuries in the athlete

MR arthrographic assessment of suspected posteroinferior labral lesions using flexion, adduction, and internal rotation positioning of the arm: preliminary experience

OBJECTIVE

Imaging the shoulder in the position of flexion, adduction, and internal rotation (FADIR) may be useful in characterizing lesions of the posteroinferior labrum. The purpose of this preliminary study is to illustrate the diagnostic utility of FADIR positioning in the assessment and characterization of posteroinferior labral tears.

MATERIALS AND METHODS

In the FADIR position, the arm is placed across the chest, with the hand on the contralateral shoulder and palm facing outwards. FADIR positioning was performed if there was a subtle or equivocal abnormality of the posteroinferior labrum on conventional MR arthrography sequences. A retrospective review of the charts of 9 people who were imaged using FADIR positioning in addition to routine MR arthrographic sequences of the shoulder was performed. The review included the indication for the study, documentation of presence of clinical posterior instability, and surgical correlation, where available.

RESULTS

In all 9 patients, FADIR positioning helped confirm, exclude, or better characterize a posteroinferior labral abnormality by increasing the diagnostic confidence.

CONCLUSION

Flexion, adduction, and internal rotation positioning appears to be a useful adjunct in evaluating patients with equivocal or subtle posteroinferior labral abnormalities on conventional MR arthrography sequences.

Spectrum of shoulder injuries in the baseball pitcher

This review describes a range of shoulder injuries experienced by baseball pitchers. It is estimated that more than 57% of pitchers suffer some form of shoulder injury during a playing season. Knowledge of the overhead throwing cycle is crucial for our understanding of these shoulder injuries. Baseball pitchers are prone to rotator cuff tears from tensile overload and impingement. Glenoid labrum degeneration or tears are also common, due to overuse syndrome (micro-instability), internal impingement and microtrauma. An understanding of the lesions involved in overhead throwing is crucial in baseball pitchers, as long-term disability can result from these injuries, sometimes with severe financial consequences to the player.

Shoulder MR arthrography of the posterior labrocapsular complex in overhead throwers with pathologic internal impingement and internal rotation deficit

PURPOSE

To determine if overhead-throwing athletes with internal impingement pain and internal rotation deficit have thickening of the posterior inferior labrocapsular complex on MR arthrogram images.

MATERIALS AND METHODS

This study was approved and a waiver of consent granted by our institutional review board. Twenty-six overhead-throwing athletes with internal impingement pain and internal rotation deficit, and 26 controls who had undergone MR arthrograms, were retrospectively examined. The MR studies were combined and read in a blind fashion. On an axial image through the posteroinferior glenoid rim, the readers measured the labral length, capsule-labrum length, and the posterior recess angle. A t-test was used to determine statistical significance.

RESULTS

The mean labral length was 4.9 mm [standard deviation (SD) 1.4 mm] for the controls, and 6.4 mm (SD 1.6 mm) for the athletes (P = 0.001). The mean capsule-labrum length was 5.4 mm (SD 2.1 mm) for the controls, and 8.8 mm (SD 2.9 mm) for the athletes (P < 0.001). The mean posterior recess angle measured 65 degrees (SD 27 degrees) for the controls and 94 degrees (SD 38 degrees) for the athletes (P = 0.002).

CONCLUSIONS

Overhead-throwing athletes with internal impingement pain and internal rotation deficit tend to have a thicker labrum and a shallower capsular recess in the posterior inferior shoulder joint than do non-overhead-throwing athletes. In many, the posteroinferior capsule is also thickened. These MR findings should alert the radiologist to closely inspect the posterior cuff and posterosuperior labrum for the tears associated with internal impingement.

Técnica e indicaciones de la resonancia magnética artrografía. Extremidad superior (I)

Magnetic resonance (MR) is the most effective imaging technique in the diagnosis of articular pathology. MR arthrography (MRA), with intra-articular injection of diluted gadolinium or physiological saline solution has become more common in recent years. The intra-articular fluid facilitates the detection of articular pathology by delineating the articular structures, separating adjacent anatomic structures, and filling potential spaces that originate in or communicate with the joint. MRA provides additional information about the integrity of the articular structures, especially cartilage, fibrocartilage, and ligaments. MRA has proven especially useful in the shoulder, where most of the studies have been centered. The detection of subtle lesions of the capsule/labrum complex is fundamental for presurgical evaluation. MRA can be used to complement conventional MR imaging in some cases and in others it is the initial technique of choice. Indirect MRA with intravenous gadolinium administration is based on the enhancement of articular fluid caused by diffusion from the synovial space to the articular space. This technique offers better results in articulations with less capacity for distension, such as the wrist, ankle, hand, and foot. This first part of two-part article reviews the current role of MRA in the upper limb. Special emphasis is placed on the shoulder joint, where its usefulness has been most clearly established. The usefulness of this technique in other joints is also described, reviewing the most important anatomic aspects, techniques and applications.

Imaging of the painful shoulder in throwing athletes

A wide spectrum of abnormalities can affect the throwing shoulder. The injuries are often particular to a specific phase of the throw and are well demonstrated with MR imaging. In this article, the authors review the phases of the throw, MR imaging techniques, and the MR appearances of the injuries associated with particular phases.