Shoulder instability : a clinical and MRI-based analysis

Abstract

Shoulder instability is a common but complex and challenging area of shoulder pathology, and new diagnostic methods and treatments are continuously developed. We conducted this study to evaluate the clinical outcome of shoulder instability with respect to different diagnostic possibilities and surgical treatments.

We have studied the patient material from our department, consisting of atraumatic instability, posttraumatic recurrent anterior instability, and primary shoulder dislocations. This was done by following up surgical treatments. We also evaluated diagnostic enhancement by arthroscopy and MR-arthrography, as well as the use of MRI as a prognostic tool in primary dislocations. To measure the clinical outcome, we have validated a Swedish translation of a self-evaluating shoulder instability score.

Study I: 27 shoulders with atraumatic shoulder instability were treated with a capsular imbrication procedure and followed up after 2 years or more. Capsular imbrication was found to be a good treatment for involuntary atraumatic shoulder instability in cases where physical rehabilitation and lifestyle adjustment have failed.

Study II: A prospective study comparing detection of lesions in recurrent instability of the shoulder on MR arthrography imaging (MRA) and arthroscopy was made in 50 patients. An assessment of agreement between MRA observers and observer repeatability show that MRA is a potentially useful tool for the detection of lesions associated with shoulder instability, and promises acceptable reliability and repeatability.

Study III: The WOSI score questionnaire is a tool designed for self-assessment of shoulder function for patients with instability problems. We retested a translation of the score into Swedish. At this retest the WOSI score had good validity, high reliability, and high responsiveness, at the same level as in the original publication.

Study IV: 60 patients with primary posttraumatic shoulder dislocation were treated with closed reduction and examined by MRI within 2 weeks. Ages above 30, isolated fractures of the major tubercle, and Bony Bankart lesions were all prognostic factors for a good functional result and a stable shoulder at 8-year follow-up after a primary dislocation.

Study V: This randomised study compares an anatomical repair (Bankart suture) with a less anatomical method (Putti-Platt procedure). The Putti-Platt procedure was found to be quicker and less demanding. After assessment of pain and general shoulder function, only a small difference was found between the two surgical methods, with a slightly better outcome (in terms of pain and ROM) with a Bankart suture compared to the Putti-Platt procedure.