Rockwood Adults CH34

1084

SECTION TWO • Upper Extremity

score—signifies extreme distress in shoulder-related quality of life). The test and retest reliability of the WOSI was 0.95 in the English language version and 0.94 in the Swedish language ver- sion. 195 The WOSI is widely used in clinical research in patients with shoulder instability and it is more responsive to the treat- ment of instability than both the ASES and DASH scores as well as the Rowe questionaire. 122,123 Oxford Instability Shoulder Score (OISS) or Oxford Shoulder Instability Questionnaire (OSIQ) The OISS or OSIQ was developed by Dawson et al. 54 in 1999 to assess PROs after shoulder instability. Several names and abbreviation have been used synonymously (OISS or OSIQ). The score in the test was generated by patient interviews. The questionnaire comprised 12 items, each of which has a total of five response categories ranked from the least to the most difficult. The items cover episodes of instability, daily activities, pain, work, social life, sports/hobbies, attention to shoulder problems, lifting, and lying positions with a total possible score ranging from 12 (best function) to 60 (worst function). Melbourne Instability Shoulder Scale (MISS) The MISS was developed by Watson et al. 257 in 2005 as a new instability-specific, self-administered questionnaire for shoulder instability. All of the items were generated from surgeon discus- sions, literature review, and patient interviews. These were fur- ther ranked based on importance by patients and surgeons, and a 22-item questionnaire was created with four total domains: Pain (4 items), Instability (5 items), Function (8 items), and Occu- pation/sports (5 items). Each item was scored using a 5-point Likert scale with 0 (worse score) to 100 points (best score). Watson et al. 257 reported the test–retest reliability of the MISS was 0.98 and has a greater range to detect changes in shoulder instability than the global Shoulder Rating Questionnaire (SRQ). Anatomically, the shoulder joint is uniquely arranged such that the lack of articular bony contact provides the joint with six degrees of freedom and ROM which makes it more suscepti- ble to dislocation and injury. The shoulder joint relies on both static and dynamic structures that collectively maintain sta- bility through the mid and end ranges of motion. Important static stabilizers include the articular anatomy of the joint with matched concavity and convexity of the ball-in-socket, as well as the glenoid labrum, which broadens and deepens the socket depth (Fig. 34-27). The vacuum seal of the closed joint capsule results in negative intra-articular pressure which may enhance the stabilizing effect of the capsuloligamentous structures. The balance between the static and dynamic stabilizers determines the stability of the shoulder joint. An imbalance among these stabilizing factors may result in instability occurring in the anterior, posterior, or inferior directions or it may be multi-directional in nature. 104,132,149 In addition to the above dynamic PATHOANATOMY AND APPLIED ANATOMY RELATED TO GLENOHUMERAL INSTABILITY

TABLE 34-2. ABC Classification of Posterior Dislocation A First Time B Dynamic

C Static

Type 1

Subluxation

Functional

Constitutional

Type 2

Dislocation

Structural

Acquired

instability: first time, dynamic, or static. Group A or first-time traumatic posterior dislocation is further subdivided into sub- luxation (A1) or dislocation with temporary engagement (A2). In the case of no significant bony or soft tissue defects, conserva- tive management is indicated. Critical humeral head or glenoid defects in patients with locked posterior dislocation (A2) will require either closed or open reduction with possible recon- struction based on the size of the defect. Group B comprises all patients with recurrent dynamic posterior instability that occurs during motion in the form of either functional (B1) or structural (B2) instability. In the functional group, pathologic activation of the rotator cuff muscles and the periscapular musculature results in abnormal posterior-directed forces in addition to underlying hyperlaxity, posterior capsule redundancy, or dysplasia. Conser- vative management with physical therapy is the recommended treatment method. In the B2 group, patients have dynamic instability with related structural damage including posterior Bankart lesions, glenoid bone loss, or reverse Hill–Sachs lesions. In these patients who have persistent pain after a trial of physical therapy, surgical management addressing the structural defect can provide a good to excellent outcome. Group C patients have chronic static instability by either constitutional structural deficiencies (C1) or acquired structural defects (C2). Surgical options include posterior capsulorrhaphy, bone grafting, glenoid osteotomy, or arthroplasty in the subset of patients with arthritis. These patients are difficult to manage with technically demand- ing procedures and unpredictable outcomes. OUTCOME MEASURES FOR GLENOHUMERAL INSTABILITY Western Ontario Shoulder Instability Index (WOSI) The WOSI is a validated patient-reported outcome (PRO) tool that was developed in 1998 by Kirkley et al. 121 for the evalua- tion of the disease-specific quality of life in patients with shoul- der instability. Items in the WOSI questionnaire were generated from the World Health Organization definition of health, expert reviews, and literature review as well as patient interviews. It is proven to be a useful outcome measure in several major clin- ical studies and has been translated and validated in Italian, German, Swedish, and Japanese. 202 The WOSI questionnaire consists of 21 items with each one scored on a 100 mm of Visual Analogue Scale (VAS). 240 There are four total domains to the WOSI with each item falling in to physical function (10 items), sports/recreation/work (4 items), lifestyle (4 items) and emo- tional well-being (3 items). Every question is scored between 0 and 100 points based on the VAS. The final score can range from 0 (best possible score—normal shoulder) to 2,100 (worse