Arthroscopic management of multidirectional instability

The acute effects of vibratory stimuli during exercise on the sensorimotor control of the shoulder complex: A pilot study

BACKGROUND

Functional stability of the shoulder requires a balance of active forces, passive forces, and control subsystems of the joint complex. Although whole-body vibration enhances shoulder muscle function and proprioception, the impact of vibration on the sensorimotor control of the shoulder joint remains unclear.

OBJECTIVE

To investigate the acute effect of vibratory stimuli on the sensorimotor control of the shoulder joint.

METHODS

Fifteen male participants (age, 22.7 ± 2.3 years) were included and performed the exercise in a modified push-up position with partial weight-bearing on a vibration platform with and without vibratory stimuli. The vibration protocol included six sets lasting for 30 s each with a 30-s rest between sets. The main outcome measures included the upper limb static stability test, Upper Quarter Y Balance Test (UQYBT), and electromyography data of the upper limb.

RESULTS

Vibratory stimuli resulted in an increased UQYBT score (all directions; P< 0.01) and infraspinatus, serratus anterior, and lower trapezius muscle activity (P< 0.05) between pre- and post-exercise versus the control condition. Stabilometric parameters showed no significant interaction between condition and time.

CONCLUSIONS

Vibratory stimuli could maximize training benefits while limiting injury risk for athletes. Our findings could guide the development of rehabilitation programs for patients with shoulder instability.

MR arthrography including abduction and external rotation images in the assessment of atraumatic multidirectional instability of the shoulder

OBJECTIVE

To evaluate diagnostic signs and measurements in the assessment of capsular redundancy in atraumatic multidirectional instability (MDI) of the shoulder on MR arthrography (MR-A) including abduction/external rotation (ABER) images.

METHODS

Twenty-one MR-A including ABER position of 20 patients with clinically diagnosed MDI and 17 patients without instability were assessed by three radiologists. On ABER images, presence of a layer of contrast between the humeral head (HH) and the anteroinferior glenohumeral ligament (AIGHL) (crescent sign) and a triangular-shaped space between the HH, AIGHL and glenoid (triangle sign) were evaluated; centring of the HH was measured. Anterosuperior herniation of the rotator interval (RI) capsule and glenoid version were determined on standard imaging planes.

RESULTS

The crescent sign had a sensitivity of 57 %/62 %/48 % (observers 1/2/3) and specificity of 100 %/100 %/94 % in the diagnosis of MDI. The triangle sign had a sensitivity of 48 %/57 %/48 % and specificity of 94 %/94 %/100 %. The combination of both signs had a sensitivity of 86 %/90 %/81 % and specificity of 94 %/94 %/94 %. A positive triangle sign was significantly associated with decentring of the HH. Measurements of RI herniation, RI width and glenoid were not significantly different between both groups.

CONCLUSIONS

Combined assessment of redundancy signs on ABER position MR-A allows for accurate differentiation between patients with atraumatic MDI and patients with clinically stable shoulders; measurements on standard imaging planes appear inappropriate.

KEY POINTS

MR arthrography has the possibility to accurately identify patients with atraumatic MDI. Imaging of the shoulder in abduction and external rotation provides additive information. Capsular enlargement of the shoulder can be diagnosed on MR arthrography.

Diagnostic performance of magnetic resonance arthrography of the shoulder in the evaluation of anteroinferior labrum abnormalities: a prospective study

OBJECTIVE

To evaluate the diagnostic performance of magnetic resonance (MR) arthrography of the shoulder in the diagnosis of anteroinferior labrum lesions, using arthroscopy as the reference standard and to classify these lesions.

METHODS

Institutional review board approval was obtained. The study population included 59 consecutive patients with history and clinical diagnosis of acute or chronic anterior shoulder instability. A total of 62 MR arthrograms were performed, since three patients had undergone a bilateral procedure. Arthroscopy, which was performed within a mean of 3 months (range 2-5 months) after MR arthrography, was used as the reference standard. Sensitivity, specificity, accuracy, positive and negative predictive values were then calculated.

RESULTS

MR arthrography showed a sensitivity of 96 % and a specificity of 80 % for the overall detection of anteroinferior labrum abnormalities. The diagnostic accuracy was 95 % and the positive and negative predictive values were 98 % and 66 % respectively. Ten lesions were non-classifiable on surgery, of which eight were non classifiable on MR arthrography also.

CONCLUSIONS

MR arthrography is highly accurate for the detection and classification of shoulder anteroinferior labrum lesions. Shoulder surgeons can confidently rely on this method to determine which patients will benefit from arthroscopy.

MAIN MESSAGES

• MR arthrography is accurate for the detection and classification of shoulder labrum lesions. • MR arthrography is a valuable tool for the preoperative planning in acute or chronic instability. • Shoulder surgeons can rely on this method to determine which patients will benefit from arthroscopy.

Open capsular shift and arthroscopic capsular plication for treatment of multidirectional instability

PURPOSE

To compare the results of open inferior capsular shift with arthroscopic capsular plication for multidirectional instability in patients without a Bankart lesion. We hypothesized that there is no difference with regard to the specific clinical outcomes evaluated, including recurrent instability, range of motion, return to sport, and complications.

METHODS

We conducted a comprehensive literature search. Databases searched included PubMed from 1966 to 2010, the Cochrane Database of Systematic Reviews and Controlled Trials, CINAHL (Cumulative Index to Nursing and Allied Health Literature) from 1982 to 2010, and SPORTDiscus from 1975 to 2010. Limits included English language, human subjects, and title.

RESULTS

We found 7 articles with a total of 197 patients (219 shoulders) that met our inclusion criteria. The data did not clearly show open treatment to be superior to arthroscopic treatment. No study reported a consistent loss of greater than 40° of external rotation. No technique showed significantly less external rotation loss over the other. Whereas there was a slight trend toward increased return to sport for patients treated arthroscopically, no clear conclusion can be drawn given the variability of reporting in the reviewed studies. Analysis of complications shows that both procedures are reliably safe with minimal complications.

CONCLUSIONS

When one is evaluating patients with traumatic or atraumatic onset of shoulder instability in 2 directions and no structural lesions, arthroscopic capsular plication yields comparable results to open capsular shift with regard to recurrent instability, return to sport, loss of external rotation, and overall complications.

Magnetic resonance imaging in glenohumeral instability

The glenohumeral joint enables tremendous range of motion at the expense of stability. Functional stability is maintained by the synchronous coordination of complex static and dynamic structures. Symptomatic glenohumeral instability most often results from injury to the inferior labral-ligamentous complex, the primary passive stabilizer of the shoulder. This article reviews the structures important in glenohumeral stabilization and illustrates their normal appearances and the abnormalities associated with anterior, posterior, and multidirectional instability. These lesions are discussed in the context of therapeutic decision making.