How successful are we in shoulder stabilization?

Abstract

The shoulder is the most mobile joint in the human body, mainly due to minimal osseous constraint. Soft-tissue structures such as muscles, ligaments, tendons, and labrum are divided into active and passive stabilizers and are responsible for primary stability. The weakest part of the soft-tissue envelope around the shoulder is the anterior region, i.e., the rotator cuff interval located between the supraspinatus and subscapularis muscles. Shoulder dislocations occur in the anterior direction in 90 % of all cases. Unidirectional instability caused by trauma often requires surgery. However, we now have good knowledge that the risk of second dislocation decreases with increasing age. One may primarily consider nonsurgical treatment when the patient is[30 years of age [5]. Younger patients require early surgery to prevent redislocation and further damage to the joint. Different pathologies are found after acute shoulder dislocation, such as labral tears, anterior capsular laxity, and glenohumeral ligament insufficiency. Also, superior labral tear, rotator cuff tear, Hill–Sachs fracture, or anterior glenoid fracture are commonly seen [4]. These pathological findings are probably more common than previously anticipated and need to be addressed during surgery in order to achieve the best possible clinical outcome. However, the redislocation rate after shoulder stabilization surgery shows a range between 6 % and 30 %. The question remains: why does the failure rate differ so much between studies? Several factors may cause failure after shoulder stabilization surgery. These factors are partly patient related (age, sex, shoulder anatomy, degree of joint laxity, sports activity level and type, number of previous dislocations, dominant side, compliance, and reinjury), partly surgery related (surgical technique), and partly related to the pathology itself [bony or soft-tissue injury of the anterior part of the shoulder, and combined injuries, such as superior labral anterior and posterior (SLAP) lesions or rotator cuff tear]. A multitude of clinical studies are available in the literature focusing on outcome after shoulder stabilization. However, it is still difficult to take all factors into account when analyzing the patient-related outcome. It is even more difficult to weight between these factors. Most of the time there is a lack of information about the important predisposing factors of shoulder instability in order to be able to analyze in detail the reason for failure. A review of the literature might help provide useful information with regards to the indication for nonsurgical or surgical management, timing of shoulder repair, and to clarify which surgical procedure might be the most appropriate. The lead article of this issue of the journal focuses on risk factors that might cause failure after Bankart repair and summarizes the articles published in peer-reviewed journals over the last 10 years [7]. Interesting findings are reported, but most of these studies present level IV evidence. Patient age, gender, and dislocation number appear to have a significant impact on outcome. For instance: why do men tend to experience shoulder dislocation more frequently than women? One may expect more dislocations in women due to the natural joint laxity. Anatomical studies of the glenoid show differences in shape and height to width ratio between genders [6]. However, the impact of those differences on the incidence of shoulder dislocation remains unclear. R. Becker (&) Department of Orthopaedic and Trauma Surgery, Hospital Brandenburg, Hochstrasse 26, 14770 Brandenburg, Havel, Germany e-mail: roland_becker@yahoo.de