The shoulder is the most frequently dislocated joint in the body. Multiple causes and pathologies account for the various types of shoulder instability. Multi-directional instability (MDI) and multi-directional laxity with anteroinferior instability (MDL-AII) are similar in pathology, less common and more difficult to treat. These types of shoulder instability are caused by ligamentous capsular redundancy. When non-operative management fails for these patients, their quality of life is significantly impaired and surgical treatment is required to tighten the loose ligaments and joint capsule. A new way to treat these patients involves arthroscopic thermal shrinkage of the tissue to tighten the joint. However, there is a lack of scientific evidence to support the use of this technique called, electrothermal arthroscopic capsulorrhaphy (ETAC). The current reference (gold) standard treatment for these patients is an open inferior capsular shift (ICS) procedure. Therefore, this trial will compare the effectiveness of these surgical techniques (ETAC vs. ICS) in patients with MDI and MDL-AII by determining patient related quality of life.~This study is designed as a multicentre, randomized controlled trial. Patients diagnosed with either MDI or MDL-AII who failed standardized non-operative management will undergo a diagnostic shoulder arthroscopy, and if appropriate, will be subsequently randomized in the operating room to either an ETAC or ICS surgical procedure. Computer-generated, stratified block randomization is used. Stratification is based on two variables:~surgeon - to account for any differences between surgeons, and~diagnosis (MDI or MDL-AII) - to account for any differences in the severity of pathology.~The disease-specific quality of life is assessed using a validated questionnaire, the Western Ontario Shoulder Instability Index, measured at baseline, and 3, 6, 12 and 24 months. The WOSI index has 21 questions, divided into four categories to assess physical symptoms, sport/recreation/work, lifestyle and emotions. Each question is scored out of 100 using a visual analog scale response format. A lower score reflects a better quality of life.
This trial will compare the effectiveness of electrothermal arthroscopic capsulorrhaphy (ETAC) to the current reference standard procedure, open inferior capsular shift (ICS), for the treatment of shoulder instability caused by ligamentous capsular redundancy. Multi-directional instability (MDI) and multi-directional laxity with anteroinferior instability (MDL-AII) are the two types of shoulder instabilities included in this trial.~Hypothesis: There is no difference in disease-specific quality of life between patients undergoing an ETAC versus an open ICS for the treatment of shoulder instability caused by capsular ligamentous redundancy.