Arthroscopic Stabilization of the Multidirectional Instability of the Shoulder: a Retrospective Review of 2- to 5-Year Clinical Results (SS-09)

Abstract

Multidirectional instability of the shoulder is an elusive diagnosis that lacks a precise definition and has multiple etiologies. The purpose of the current study is to present and interpret the results of an arthroscopic stabilization of the patients with multidirectional instability of the shoulder at our institution from 2003 to 2010. From 2003 to 2010 there were 68 patients that had a diagnosis of multidirectional instability (MDI) of the shoulder who were identified at out institution using the CPT code. All 68 patients have been diagnosed with MDI using a thorough history and physical exam, as well as radiographic modalities such as plain radiography and MRI. The patients have initially gone through an extensive course of non-operative therapy, which ultimately did not yield satisfactory functional results, and all patients had an arthroscopic stabilization of their instability. The indications for surgery were the failure of non-operative treatment, persistent pain, instability, and limitation of function. The patient parameters were recorded including the direction of instability, the mode of injury, the surgical fixation. The functional results of instability postoperatively were calculated using the Rowe Score for Instability. There were 24 males and 44 females with 41 right and 27 left shoulders affected. The average follow up was 6.7 months. Two patients had persistent dislocation postoperatively and required revision surgery. The success rate of patients regaining normal strength, stability, and function was 95.6% (65 out of 68). 16 patients sustained a traumatic event that led to the MDI. The athletic patient population participated in football, baseball, basketball, tennis, and swimming with most common sports associated with MDI being football and baseball. The direction of MDI was confirmed with exam under anesthesia and it varied from antero-posterior-inferior (58.8%) being most common to antero-inferior, and postero-inferior (8.8%) being least common. The Rowe Score for Instability was used to calculate the functional outcome with 100 being highest. The mean Rowe Score was 95.9 with 65 out of 68 patients ultimately achieving full function and stability. Three patients had less than satisfactory results with Rowe Score bein 45, 55, and 65 with the overall failure rate of 4.4%. The surgical stabilization included capsulorhaphy, labral fixation, Bankart repair and rotator interval plication where indicated and depending on the instability pattern. 37 patients required rotator interval closure in addition to capsuloraphy. Arthroscopic fixation of MDI of the shoulder requires precise knowledge and understanding of pathoanatomy of instability. Our retrospective study of 68 patients is the largest MDI study to date with excellent surgical outcomes in 95.6% of patients. The arthroscopic treatment of MDI allows for less morbidity relative to the open surgery and quicker rehabilitation due to the minimally invasive approach. The arthroscopic stabilization of MDI yields excellent results and is a viable alternative to an open approach.