Intermediate biomechanical analysis of the effect of physiotherapy only compared with capsular shift and physiotherapy in multidirectional shoulder instability

Comprehensive Review of Multidirectional Instability of the Shoulder

Multidirectional instability of the shoulder can result from underlying atraumatic laxity, from repetitive microtrauma, or from a traumatic injury and often occurs in association with generalized ligamentous laxity or underlying connective tissue disorders. It is critical to differentiate multidirectional instability from unidirectional instability with or without generalized laxity to maximize treatment success. Although rehabilitation is still considered the primary treatment method for this condition, surgical treatment in the form of open inferior capsular shift or arthroscopic pancapsulolabral plication is indicated if conservative treatment fails. Recent biomechanical and clinical research has shown that there is still room for improvement in the treatment methods offered to this specific patient cohort. Potential treatment options, such as various methods to improve cross-linking of native collagen tissue, electric muscle stimulation to retrain the abnormally functioning dynamic stabilizers of the shoulder, and alternative surgical techniques such as coracohumeral ligament reconstruction and bone-based augmentation procedures, are brought forth in this article as potential avenues to explore in the future.

Multidirectional instability of the shoulder: surgical techniques and clinical outcome

Multidirectional instability of the shoulder has a complex pathoanatomy. It is characterized by a redundant glenohumeral capsule and increased joint volume. Subtle clinical presentation, unclear trauma history and multifactorial etiology poseses a great challenge for orthopedic surgeons in terms of diagnosis. Generally accepted therapeutic approach is conservative and the majority of patients achieve good results with rehabilitation. In patients who are symptomatic despite appropriate rehabilitation, surgical intervention may be considered. Good results have been obtained with open inferior capsular surgery, which has historically been performed in these patients. In recent years, advanced arthroscopic techniques have taken place in this field, and similar results compared to open surgery have been obtained with the less-invasive arthroscopic capsular plication procedure.

Muscle activity and scapular kinematics in individuals with multidirectional shoulder instability: A systematic review

BACKGROUND

Several studies reported the importance of glenohumeral and scapular muscle activity and scapular kinematics in multidirectional shoulder instability (MDI), yet a systematic overview is currently lacking.

OBJECTIVE

This systematic review evaluates and summarizes the evidence regarding muscle activity and shoulder kinematics in individuals with MDI compared to healthy controls.

METHOD

The electronic databases PubMed and Web of Science were searched in September 2020 with key words regarding MDI (population), muscle activity, and glenohumeral and scapular movement patterns (outcomes). All studies that compared muscle activity or scapular kinematics between shoulders with MDI and healthy shoulders were eligible for this review, except for case reports and case series. All articles were screened on the title and abstract, and remaining eligible articles were screened on full text. The risk of bias of included articles was assessed by a checklist for case-control data, as advised by the Cochrane collaboration.

RESULTS

After full text screening, 12 articles remained for inclusion and one study was obtained by hand search. According to the guidelines of the Dutch Institute for Healthcare Improvement, most studies were of moderate methodological quality. We found moderate evidence that MDI individuals show increased or prolonged activity of several rotator cuff muscles that control and centre the humeral head. Furthermore, we found evidence of decreased and/or shortened activity of muscles that move or accelerate the arm and shoulder girdle as well as increased and/or lengthened activity of muscles that decelerate the arm and shoulder girdle. The most consistent kinematic finding was that MDI individuals show significantly less upward rotation and more internal rotation of the scapula during elevation of the arm in the scapular plane as compared with controls. Finally, several studies also suggest that the humeral head demonstrates increased translations relative to the glenoid surface.

CONCLUSION

There is moderate evidence for altered muscle activity and altered humeral and scapular kinematics in MDI individuals as compared with controls.

Multidirectional Instability of the Shoulder: Treatment Options and Considerations

Multidirectional instability (MDI) is a debilitating condition that involves chronic subluxation or dislocation of the shoulder in >1 direction. Numerous proposed mechanisms of MDI exist, which occurs in the setting of redundant capsular tissue. Symptoms can range from recurrent dislocations or subluxations to vague aching pain that disrupts activities of daily living. Magnetic resonance imaging is often performed during evaluation of this condition, although magnetic resonance arthrography may provide more detailed images of the patulous capsule. In the absence of a well-defined traumatic cause, such as a labral tear, initial treatment for MDI is a structured rehabilitation program with exercises aimed at strengthening the rotator cuff and periscapular muscles to improve scapular kinematics. Patients with recalcitrant symptoms may benefit from surgical stabilization, including open capsular shift or arthroscopic capsular plication, aimed at decreasing capsular volume and improving stability.

Effects of surgical management on multidirectional instability of the shoulder: a meta-analysis

PURPOSE

The purpose of this study was to assess the effectiveness of arthroscopic and open surgical techniques on the treatment of shoulder multidirectional instability.

METHODS

Literature searches were conducted using the databases MEDLINE, Embase, ClinicalTrials.gov, the Cochrane Library, and the Cochrane Central Register of Controlled Trials. Original articles on the surgical management of multidirectional instability were retrieved against selection criteria. Data were extracted and divided into three groups by surgical technique. Proportion and mean meta-analyses were performed for comparison.

RESULTS

The available evidence was from 35 level IV and 1 level II studies. The recurrent instability rate was 9.9 % (95 % CI 7.3-12.9 %) in open capsular shift (OCS) group and 6.0 % (95 % CI 3.7-8.9 %) in arthroscopic capsular plication (ACP) group, between which no difference was observed. However, thermal capsular shrinkage (TCS) group resulted in a recurrent instability rate of 23.9 % (95 % CI 16.6-32.2 %), significantly higher than the above two groups. OCS and ACP groups revealed low reoperation rates of approximately 5.2 % (95 % CI 2.7-8.5 %) and 4.8 % (95 % CI 2.3-8.0 %), respectively, which are lower than that in TCS group of 16.9 % (95 % CI 12.4-21.8 %). OCS caused more loss of external rotation than ACP, losing 7.0 (95 % CI 3.3-10.6) degrees versus 2 (95 % CI 0.9-2.4) degrees, respectively.

CONCLUSIONS

ACP and OCS techniques have similar primary outcomes, but the former causes less post-operative stiffness. It is suggestible to avoid TCS in the treatment of MDI.

LEVEL OF EVIDENCE

Level IV.

Multidirectional Instability of the Shoulder: A Systematic Review

PURPOSE

To analyze outcomes of surgical and conservative treatment options for multidirectional instability (MDI).

METHODS

A systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. A comprehensive search of the PubMed, MEDLINE, CINAHL, Cochrane, EMBASE, and Google Scholar databases using various combinations of the keywords "shoulder," "multidirectional instability," "dislocation," "inferior instability," "capsulorrhaphy," "capsular plication," "capsular shift," "glenoid," "humeral head," "surgery," and "glenohumeral," over the years 1966 to 2014 was performed.

RESULTS

Twenty-four articles describing patients with open capsular shift, arthroscopic treatment, and conservative or combined management in the setting of atraumatic MDI of the shoulder were included. A total of 861 shoulders in 790 patients was included. The median age was 24.3 years, ranging from 9 to 56 years. The dominant side was involved in 269 (58%) of 468 shoulders, whereas the nondominant side was involved in 199 (42%) shoulders. Patients were assessed at a median follow-up period of 4.2 years (ranging from 9 months to 16 years). Fifty-two of 253 (21%) patients undergoing physiotherapy required surgical intervention for MDI management, whereas the overall occurrence of redislocation was seen in 61 of 608 (10%) shoulders undergoing surgical procedures. The redislocation event occurred in 17 of 226 (7.5%) shoulders with open capsular shift management, in 21 of 268 (7.8%) shoulders with arthroscopic plication management, in 12 of 49 (24.5%) shoulders undergoing arthroscopic thermal shrinkage, and in 11 of 55 (22%) shoulders undergoing arthroscopic laser-assisted capsulorrhaphy.

CONCLUSIONS

Arthroscopic capsular plication and open capsular shift are the best surgical procedures for treatment of MDI after failure of rehabilitative management. Arthroscopic capsular plication shows results comparable to open capsular shift.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

Multidirectional instability of the shoulder: biomechanics, clinical presentation, and treatment strategies

Multidirectional instability (MDI) of the shoulder is a condition where the dislocation occurs in more than one direction with minimal or no causative trauma. Its pathoanatomy is complex and characterized by a redundant capsule, resulting in increased glenohumeral joint volume. The fact that several further factors may contribute to symptom onset complicates the diagnosis and hampers the identification of a therapeutic approach suitable for all cases. There is general agreement that the initial treatment should be conservative and that surgery should be reserved for patients who have not responded to an ad hoc rehabilitation program. We review the biomechanics, clinical presentation, and treatment strategies of shoulder MDI.