肩关节炎 资料

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Overview

• Standardization of outcome assessment following treatment of shoulder arthritis is required [1].
• Shoulder arthritis is common [2].
• Management strategies for shoulder arthritis, especially in young patients, continue to evolve [2].
• Significant improvements in implant design have occurred for shoulder arthritis management [2].
• Implant longevity remains a concern in more active patients with shoulder arthritis [2].
• Definitions of the stiff shoulder have become clearer and the classification system has become more precise [3].
• Treatment algorithms for the stiff shoulder have become more streamlined and clinical studies have become more specific regarding individual patient populations [3].
• The pathogenesis of the stiff shoulder is still elusive, though ongoing basic science research has provided insight into cellular and biochemical pathways resulting in shoulder stiffness [3].
• Diagnosis of a stiff shoulder depends on awareness of the problem, with history and physical examination being paramount [3].
• Understanding the natural history of the stiff shoulder is important so that patients are well informed and can actively participate in decision-making [3].
• No treatment for the stiff shoulder has proved to be definitive [3].
• The literature supports many forms of treatment, both operative and nonoperative, for the stiff shoulder [3].
• Treatment approaches for the stiff shoulder should be tailored to each individual patient to ensure the best possible outcome [3].
• Patients with glenohumeral osteoarthritis converted intraoperatively to reverse shoulder arthroplasty (RSA) had outcomes comparable to those who underwent total shoulder arthroplasty [5].
• Reverse shoulder arthroplasty provides optimal outcomes with low complication rates across a short term of follow-up for glenohumeral osteoarthritis with an intact rotator cuff [6].
• Patients with mild radiographic signs of arthritis have about sevenfold higher odds of failing to achieve the minimum clinically important difference (MCID) after anatomic total shoulder replacement compared to patients with severe arthritis [8].
• A clear standardised set of shoulder arthroplasty complication definitions is lacking [9].
• The Western Ontario Osteoarthritis of the Shoulder Index (WOOS) is recommended for continued use in shoulder arthroplasty registries and observational studies [15].
• Anatomic total shoulder arthroplasty (ATSA) is the benchmark for surgical treatment of glenohumeral arthritis with an intact cuff [16].
• Reverse total shoulder arthroplasty (RTSA) has gained popularity for rotator cuff arthropathy and other complex indications [16].
• Total shoulder arthroplasty did not provide a clinically important advantage over hemiarthroplasty in terms of patient-reported pain, function, nor adverse effects [19].
• The evidence regarding the comparison of total shoulder arthroplasty and hemiarthroplasty was of low quality [19].
• Knowledge of the array of shoulder prostheses currently available and the indications for each can lead to optimized patient outcomes [31].
• The use of treatment algorithms can lead to optimized patient outcomes in shoulder arthroplasty [31].
• Both augmented and standard anatomic total shoulder arthroplasty can provide satisfactory and sustained improvements in patient-reported outcomes in patients with acquired glenoid retroversion due to glenohumeral osteoarthritis [39].
• Many different shoulder arthroplasty systems are on the market, with more being introduced each year [94].
• Newer, more costly, and more complicated shoulder arthroplasty approaches often lack evidence that they yield better outcomes for the patient compared to the systems they replace [94].
• The ideal humeral component allows secure and durable placement of an ample articular surface in the position that optimizes glenohumeral motion and stability [94].
• The ideal humeral component allows for complete removal without the risk of damage to the humerus should revision become necessary [94].
• The humeral implant is modular, allowing the head and body components to be selected independently [94].
• In selecting the humeral component, optimization of glenohumeral mechanics is prioritized over attempting to restore normal anatomy [94].
• The surgeon can modify capsular tension and the fit of the component to the glenoid articular surface by adjusting the humeral diameter of curvature, head thickness, and head offset with respect to the stem [94].
• There are three types of prosthetic humeral articular surfaces: partial resurfacing, complete resurfacing, and head replacement [94].
• The modulus of elasticity varies by a factor of 200,000 between the metal prosthesis (about 200,000 MPa) and the surrounding intact articular cartilage (0.5 to 0.9 MPa) [94].
• The variation in modulus of elasticity creates a major discontinuity in the deformation of the joint surface under load at the margin of partial resurfacing prostheses [94].
• Complete resurfacing prostheses are intended to cover the arthritic humeral head [94].
• The rationale for complete resurfacing prostheses includes preserving humeral bone stock in case a subsequent arthrodesis may be required [94].
• The rationale for complete resurfacing prostheses includes enabling the surgeon to perform an arthroplasty when there is humeral deformity [94].
• The rationale for complete resurfacing prostheses includes better facilitating revision than prostheses that use cemented or bone ingrowth humeral stems [94].
• The rationale for complete resurfacing prostheses includes facilitating restoration of normal anatomy, although the restoration is not always anatomic [94].
• A more important goal of arthroplasty than reestablishing normal anatomy is to restore functional mechanics for the arthritic shoulder [94].
• Restoring functional mechanics often requires adjustments in the diameter of curvature, thickness, and orientation of the head and also requires glenoid arthroplasty [94].
• The need for arthrodesis after prior arthroplasty is extremely rare [94].
• Almost all cases of arthritic and post-traumatic deformity can be managed with a conventional stemmed prosthesis [94].
• Difficulties associated with the removal of cemented or ingrowth components can be avoided by humeral stem fixation with impaction grafting [94].
• Retaining the humeral head with resurfacing implants limits the surgeon’s ability to modify the orientation and thickness of the component [94].
• Retention of the anatomic humeral head compromises access to the glenoid, making it difficult to address the glenoid pathology encountered in glenohumeral osteoarthritis [94].
• Registry data indicate a 2.5-year revision rate for resurfacing prostheses [94].
• The 2.5-year revision rate for resurfacing prostheses is more than three times the revision rate for stemmed hemiarthroplasty [94].
• Head replacement prostheses allow extensive versatility in the selection of the humeral head component [94].
• The humeral head cut for head replacement prostheses allows excellent access to the glenoid bone so that an appropriate glenoid arthroplasty can be carried out [94].
• Some prostheses are nonspherical, but these do not appear to be superior to the spherical design found in nature [94].
• In a hemiarthroplasty in the absence of any form of glenoid arthroplasty, the shape of the socket is not changed [94].
• In a hemiarthroplasty in the absence of any form of glenoid arthroplasty, the articular surface of the humeral component should have the same diameter of curvature as the resected humeral head [94].

Anatomy & Pathophysiology

Bony Anatomy

• The proximal humerus comprises four main parts: the humeral head, greater tuberosity, lesser tuberosity, and humeral shaft [44].
• The articular head of the humerus is spherical with a diameter of 37 to 57 mm [44].
• The most superior portion of the articular surface of the humeral head averages 8 mm above the greater tuberosity [44].
• Humeral version averages 29.8 degrees, with a range of 10 to 55 degrees [44].
• The humeral head is inclined approximately 130 degrees with respect to the humeral shaft [44].
• The neck-shaft angle of the proximal humerus measures an average of 135 degrees [46].
• The humeral head is retroverted an average of 30 degrees [46].
• The humeral head averages 19° of retroversion and 41° of inclination (neck-shaft angle) [47].
• The glenoid is a convex structure of shallow depth shaped like an inverted pear [44].
• The glenoid cavity is a shallow socket, approximately one third the size of the humeral head [46].
• The subchondral bone of the glenoid is relatively flat, with the articular concavity augmented by cartilage and a circumferential labrum [47].
• The glenoid averages 5° of retroversion in relation to the axis of the scapular body [47].
• The greater tuberosity serves as the attachment site for the supraspinatus, infraspinatus, and teres minor tendons [44, 46].
• The lesser tuberosity serves as the attachment site for the subscapularis tendon [44, 46].
• The anatomic neck of the proximal humerus is located at the junction of the articular surface and the tuberosities [44, 46].
• The surgical neck represents an indistinct region (metadiaphyseal junction) below the tuberosities but above the humeral shaft [44, 46].
• The acromion, coracoacromial ligament, and coracoid process form the coracoacromial arch, a rigid bony-ligamentous structure that imparts stability to the shoulder girdle [44].
• The scapula has only one true diarthrodial articulation, the acromioclavicular joint [47].
• Normal shoulder motion is approximately two-thirds glenohumeral and one-third scapulothoracic [47].
• The acromion has three ossification centers: the metacromion (base), the mesoacromion (middle), and the preacromion (tip) [47].
• The proximal humerus has three centers of ossification: the humeral head (4 to 6 months), the greater tuberosity (1 to 3 years), and the lesser tuberosity (3 to 5 years) [47].
• The proximal humeral ossification centers fuse to the shaft at age 17 to 20 years [47].

Vascular Supply

• The proximal humerus receives its blood supply from the anterior and posterior humeral circumflex branches from the third division of the axillary artery [44].
• The posterior humeral circumflex artery travels with the axillary nerve, enters the quadrilateral space posteriorly, and anastomoses with a branch of the anterior circumflex to supply the posterior cuff [44].
• The anterior humeral circumflex artery arises from the axillary artery at the inferior border of the subscapularis [44].
• The anterior humeral circumflex artery provides vascular inflow to the humeral head by way of its terminal anterolateral branch known as the artery of Laing (also known as the arcuate artery) [44].
• The ascending branch of the anterior humeral circumflex artery courses parallel to the lateral aspect of the long head biceps tendon and enters the humeral head at the interface of the bicipital groove and greater tuberosity [44].
• Injury to the arcuate artery may result in osteonecrosis of the humeral head [44].
• Additional extraosseous collateral branches can permit humeral head perfusion despite complete ligation of the arcuate artery [44].
• The major blood supply to the humeral head is through the ascending branch of the anterior humeral circumflex artery, which penetrates the head at the bicipital groove and becomes the arcuate artery [46].
• The anterolateral ascending branch of the anterior humeral circumflex artery provides the primary blood supply to the humeral head [47].
• The terminal intraosseous portion of the anterior humeral circumflex artery enters at the proximal aspect of the intertubercular groove as the arcuate artery [47].

Soft Tissue Anatomy

• The rotator cuff consists of four muscles: the subscapularis, supraspinatus, infraspinatus, and teres minor [46].
• The teres major is not a rotator cuff muscle [46].
• The rotator cuff muscles serve as depressors of the humeral head to allow the deltoid to efficiently abduct the humerus [46].
• The infraspinatus and teres minor are external rotators, while the subscapularis is an internal rotator of the humerus [46].
• The subscapularis is the largest and strongest of the rotator cuff tendons [68].
• The subscapularis is responsible for active internal rotation of the humerus and contributes to the stability of the shoulder [68].
• The subscapularis forms the anterior portion of the transverse plane “force couple” of the rotator cuff and serves to balance forces generated across the joint to maintain glenohumeral congruency [68].
• The bicipital groove lies between the greater and lesser tuberosities and serves as a pathway for the long head of the biceps [44].
• The distal aspect of the bicipital groove is internally rotated with respect to the proximal portion [44].
• The subscapular bursa lies between the subscapularis tendon and the neck of the scapula and communicates with the joint cavity between the superior and middle glenohumeral ligaments [48].
• The subscapular bursa protects the tendon of the subscapularis at the point where it passes under the base of the coracoid process and over the neck of the scapula [48].
• The subscapular bursa often houses loose bodies in the shoulder and is a region in which synovitis of the shoulder may be most intense [48].
• The rotator interval is defined medially by the base of the coracoid, superiorly by the supraspinatus tendon, and inferiorly by the subscapularis tendon [47].
• The rotator interval contains the coracohumeral ligament, the superior glenohumeral ligament, and the intra-articular portion of the long head of the biceps tendon [47].
• Laxity of the rotator interval results in inferior laxity (the sulcus sign), and contracture of the interval is seen with adhesive capsulitis [47].
• The coracohumeral ligament restricts external rotation in adduction and is a static restraint to inferior and posterior translation in adduction and external rotation [47].
• The superior glenohumeral ligament is a primary static restraint against anterior translation with the arm at the side [47].
• With the coracohumeral ligament, the superior glenohumeral ligament forms a pulley that provides restraint against medial subluxation of the long head of the biceps tendon [47].
• The middle glenohumeral ligament is a primary static restraint against anterior translation with the arm in external rotation and 45° of abduction [47].
• The anterior band of the inferior glenohumeral ligament is a primary static restraint against anterior-inferior dislocation of the glenohumeral joint in 90° of abduction and external rotation [47].
• The posterior band of the inferior glenohumeral ligament is a primary static restraint against posterior-inferior translation in internal rotation and adduction [47].
• The glenoid labrum provides concavity and up to 50% of marginal glenoid socket depth [47].
• The superior shoulder suspensory complex provides a stable connection between the scapula and the axial skeleton [47].
• The superior shoulder suspensory complex is composed of the glenoid, the coracoid process, the coracoclavicular ligaments, the distal clavicle, the acromioclavicular joint, and the acromion [47].
• The humeroscapular motion interface lies between the inner structures of the proximal humerus, rotator cuff, coracohumeral ligament, and biceps tendon sheath and the superficial layer of the acromion, deltoid, coracoacromial ligament, coracoid process, and the conjoined tendon [50].
• Smooth, unrestricted motion at the humeroscapular motion interface is vital to shoulder mobility [50].
• The axillary nerve is a terminal branch coming off the posterior cord of the brachial plexus just proximal to the coracoid process [50].
• The axillary nerve passes beneath the conjoined tendon anterior to the subscapularis 3 to 5 mm medial to the musculotendinous junction and then adjacent to the inferior capsule before entering the quadrilateral space posteriorly [50].
• The axillary nerve splits into the anterior and posterior branches within the quadrangular space [50].
• The anterior and middle deltoid muscle receives sole innervation from the anterior branch of the axillary nerve [50].
• Posterior deltoid muscle innervation varies, with supply only from the anterior branch in 2.3% of cases, from the posterior branch in 8.5%, and from both branches in 89.1% [50].
• The posterior branch of the axillary nerve branches to supply the teres minor muscle and then terminates as the superior lateral brachial cutaneous nerve [50].

Pathophysiology

• The etiology of stiff shoulder development remains elusive, with current research focused on determining an immunologic basis and the role of cell signaling and inflammatory mediators [58].
• The disease process of idiopathic frozen shoulder is primarily a capsular pathology with signs of inflammation, fibroblast proliferation, and neovascularization [58].
• There may be an immunologic component to frozen shoulder, but there are no reliable laboratory tests or inflammatory markers to diagnose it [58].
• There is a clear association of diabetes mellitus and Dupuytren’s contracture with frozen shoulder, but the exact pathophysiologic process is mostly speculative [58].
• Current research on frozen shoulder is focused on defining the role of matrix metalloproteinases, tissue inhibitors of metalloproteinases, other cytokines, and cytogenetics [58].
• The manifestation of early glenohumeral arthritis in the young adult is a multifactorial disease process [10].
• Primary osteoarthritis of the shoulder has an unknown cause, but a genetic predisposition may be present [65].
• Secondary causes of shoulder osteoarthritis can be posttraumatic, postsurgical, or a result of persistent or recurrent shoulder instability [65].
• Posterior glenoid wear and posterior humeral head subluxation occur in up to 45% of shoulders affected by primary osteoarthritis [65].
• In primary osteoarthritis, the anterior soft tissues, including the anterior capsule and the subscapularis, become contracted, limiting external rotation [65].
• Joint space narrowing and periarticular osteophyte formation occur most commonly on the inferior aspects of the humeral head in primary osteoarthritis, a result referred to as a “goat’s beard” [65].
• Full-thickness rotator cuff tears are associated with primary osteoarthritis in 5% to 10% of cases [65].
• Rheumatoid arthritis is the most prevalent form of inflammatory arthritis affecting the shoulder [26].
• Of patients with rheumatoid arthritis for more than 5 years, 91% develop shoulder symptoms [26].
• Rheumatoid arthritis is a systemic autoimmune disorder that affects multiple joints [26].
• Erosive pannus formation within the joint and the release of inflammatory cytokines in rheumatoid arthritis result in cartilage damage, bone resorption, and soft-tissue degradation [26].
• Up to 75% of patients with rheumatoid arthritis eventually develop rotator cuff pathology [26].
• Between 25% and 30% of patients with rheumatoid arthritis have full-thickness rotator cuff defects at the time of surgery [26].
• In the dry form of rheumatoid arthritis, there is sclerosis, subchondral cysts, and loss of joint space with minimal margin erosion and marginal osteophytes [29].
• In the wet form of rheumatoid arthritis, there are exuberant granulations with marginal erosion, which causes the ends of the bone to become pointed [29].
• Severe destruction of the glenoid in the wet form of rheumatoid arthritis may occur due to granulation erosion, disuse osteopenia, and pressure erosion from the pointed end of the humerus [29].
• The wet and resorptive form of rheumatoid arthritis is associated with severe bone loss and central migration of the humerus termed “centralization” [29].
• Centralization in rheumatoid arthritis involves severe loss of bone associated with loss of the contour of the shoulder, where the point of the shoulder becomes flattened [29].
• Untreated subscapularis tears can lead to dynamic anterior instability and glenohumeral arthrosis [68].
• Rotator cuff tendons are intrasynovial and do not undergo the spontaneous healing seen in extrasynovial tendons [70].
• Healing of tendon or ligament progresses through an inflammatory phase lasting a few days, a proliferative phase lasting a few weeks, and a remodeling phase lasting months [70].
• The resultant collagen scar from tendon healing is relatively disorganized and fails to replicate the normal zonal transition at the tendon-bone insertion site [70].
• Codman described a condition in 1934 where a chronic tear of the rotator cuff may result in a hygroma of the shoulder and destruction of the glenohumeral joint [126].
• Neer et al. postulated in 1983 that certain chronic, massive rotator cuff tears would lead to a degenerated glenohumeral joint if left untreated [126].
• The mechanism of articular cartilage destruction in rotator cuff arthropathy includes mechanical and nutritional alterations [126].
• Mechanical factors in rotator cuff arthropathy include anteroposterior instability of the humeral head and rupture or dislocation of the long head of the biceps leading to proximal migration and acromial impingement [126].
• Glenohumeral articular wear in rotator cuff arthropathy occurs as a result of repetitive trauma from altered biomechanics associated with the loss of primary and secondary stabilizers [126].
• The nutritional status of articular cartilage in a shoulder with a torn rotator cuff is altered by the loss of a closed joint space and normal glenohumeral motion [126].
• Inadequate diffusion of nutrients due to diminished synovial fluid quantity causes changes in the composition of articular cartilage in rotator cuff arthropathy [126].
• Disuse osteoporosis of the proximal humerus decreases the density of the subchondral bone in the humeral head and contributes to atrophy of the articular cartilage in rotator cuff arthropathy [126].
• Most pathologic processes that afflict the shoulder affect both sexes equally, including trauma, arthritis, infection, cuff tears, avascular necrosis, calcific tendinitis, and gout [104].
• Multidirectional shoulder instability is seen much more frequently in female patients between the ages of 15 and 25 years than in male patients of the same age [104].
• Female patients tend to present in far greater numbers than males with adhesive capsulitis [104].
• Adhesive capsulitis is most prevalent in women 40 to 60 years of age and is associated with an idiopathic inflammatory process involving the glenohumeral joint capsule and synovium that results in capsular contraction and adhesion formation [104].
• Cuff tear arthropathy, defined by painful collapse of the humeral head with superior migration, is much more common in geriatric women compared with men [104].

Classification

Glenoid Morphology and Bone Loss

• Primary glenohumeral osteoarthritis is associated with distinct global scapular morphologic characteristics [7].
• Anatomic patterns of glenoid bone loss exist for different classes of glenohumeral arthritis [24].
• Pathoanatomic metrics with identified threshold values can discriminate glenoid types in shoulders with primary glenohumeral osteoarthritis [32].
• A 3D classification system using combined humeroscapular alignment and glenoid erosion can be applied to describe degenerative glenohumeral arthritis comprehensively [59].
• A small lateral extension and less posterior rotation of the acromion is associated with shoulder osteoarthritis and is present in almost all types and subtypes of glenoid morphology [75].
• In a cohort of 206 shoulder CT scans, 109 shoulders with primary glenohumeral osteoarthritis were classified as type A1 in 33%, A2 in 19%, B1 in 18%, B2 in 26.5%, and C2 in 3.5% [109].
• Among patients requiring shoulder arthroplasty after anterior instability surgery, 55.1% exhibited A1-type osteoarthritis, 18.4% A2, 16.3% B1, and 10% B2 at the time of conversion [18].

Humeral Head and Joint Alignment

• Osteoarthritic humeral head morphology varies significantly from normal with larger spherical diameters, but does not vary as a function of the Walch classification between symmetric and asymmetric glenoids [106].
• Shoulders presenting with posterior subluxation (B types) remained posteriorly subluxed, while concentric arthritis developed an eccentric pattern 20% of the time over a decade [33].
• The Samilson and Prieto classification system grades inferior humeral head osteophytes by millimeters of extension, with <3 mm as grade I, 3 to 7 mm as grade II, and >7 mm as grade III [120].
• A modified Samilson and Prieto classification includes an osteophyte between 8 and 12 mm as grade III and >12 mm as grade IV [120].

Rheumatoid Arthritis

• Rheumatoid arthritis involvement is classified clinically as low-grade, intermediate, or severe to aid in clinical decision-making [29].
• In the dry form of rheumatoid arthritis, there is sclerosis, subchondral cysts, and loss of joint space with minimal margin erosion and marginal osteophytes similar to those seen in osteoarthritis [29].
• In the wet form of rheumatoid arthritis, exuberant granulations cause marginal erosion that results in pointed bone ends and severe glenoid destruction [29].
• Centralization in rheumatoid arthritis is characterized by severe bone loss, a flattened shoulder point resembling a Burgundy wine bottle, and difficulty in implanting a glenoid component [29].
• Glenoid wear in rheumatoid arthritis on a true AP view is staged as stage 1 (subcondral bone intact or minimally deformed), stage 2 (wear reaching the foot of the coracoid), and stage 3 (wear beyond the foot of the coracoid) [29].

Septic Arthritis

• Septic arthritis is divided arthroscopically into four stages: Stage I (opacity of fluid, redness, no radiological alterations), Stage II (severe inflammation, fibrinous deposition, pus, no radiological alterations), Stage III (synovial thickening, compartment formation, no radiological alterations), and Stage IV (aggressive pannus, cartilage infiltration, subchondral osteolysis) [93].
• A proposed classification system for septic arthritis of the shoulder stages the infectious process using four anatomic types, three host physiologic classes, and two clinical settings [93].
• Anatomic type I of septic arthritis is periarticular soft-tissue infection without pyarthrosis [93].
• Anatomic type II of septic arthritis is isolated septic arthritis where purulent material is confined within the capsule [93].
• Anatomic type III of septic arthritis involves the joint and surrounding soft tissue without bony involvement [93].
• Anatomic type IV of septic arthritis involves septic arthritis with contiguous osteomyelitis, usually involving the proximal humerus [93].
• Host class A represents a patient with a normal immune system, while host class B represents a compromised system either locally (B_L) or systemically (B_S) [93].
• Clinical setting 1 for septic arthritis is defined as less than 5 days of symptoms and a nonvirulent organism, while clinical setting 2 is symptoms for 5 days or more or a virulent organism [93].

Periprosthetic Fractures

• The Wright and Cofield classification divides periprosthetic humeral fractures associated with shoulder arthroplasty into type A (propagating proximally from the distal stem), type B (centered over the distal stem), and type C (located distal to the tip of the stem) [105].
• Current classifications exhibit poor reliability in categorizing glenoid defects post-reverse shoulder arthroplasty removal [67].

Rotator Cuff and Muscle Atrophy

• The Goutallier classification grades fatty infiltration of rotator cuff musculature from Grade 0 (normal muscle without fatty streaks) to Grade 4 (more fat than muscle) [110].
• Fuchs simplified the Goutallier classification into three categories by combining grades 0 and 1 as normal and grades 3 and 4 as advanced degeneration [110].
• Zanetti’s "tangent sign" is a binary method for defining atrophy where a positive sign indicates significant muscular atrophy if the supraspinatus muscle belly fails to intersect a line drawn from the superior border of the coracoid to the superior border of the scapular spine [110].
• The Thomazeau "occupation ratio" measures muscle belly cross-sectional area relative to fossa size, with 0.6 to 1.0 indicating normal or slight atrophy, 0.4 to 0.6 indicating moderate atrophy, and less than 0.4 indicating severe atrophy [110].
• In the assessment of reverse shoulder arthroplasty outcomes, fatty infiltration of the supraspinatus, infraspinatus, and subscapularis is graded using the Goutallier classification and dichotomized as functional (grades 0, 1, or 2) or nonfunctional (grades 3 or 4) [41].

Frozen Shoulder

• Primary frozen shoulder is defined by total elevation restricted to 135° or less, restriction localized to the humero-scapular joint, and no findings in history or examination explaining the decreased range of motion [113].
• Secondary frozen shoulder is defined by decreased range of motion following a traumatic lesion such as soft tissue injury or fractures [113].
• The first stage of frozen shoulder according to Reeves is characterized by pain with a duration of 10 to 36 weeks and full range of movement under an anaesthetic in early stages [113].

Acromioclavicular Joint

• The Allman classification grades acromioclavicular sprains based on ligament involvement: Grade I involves a few fibres of the acromioclavicular ligament and capsule with no laxity, Grade II involves rupture of the capsule and acromioclavicular ligament with subluxation, and Grade III involves rupture of both acromioclavicular and coracoclavicular ligaments with dislocation [112].
• The Rockwood classification is used to characterize acromioclavicular joint injuries, with type I and II injuries typically treated conservatively and type IV to VI injuries surgically treated [115].
• Grade III acromioclavicular separations are described as 100% displacement of the clavicle on radiographs compared with the contralateral side, while grade V separations are described as exaggerated superior dislocation between 100% and 300% [115].

Clinical Presentation

History and Physical Examination

• The diagnosis of a stiff shoulder depends on awareness of the problem, with history and physical examination being paramount [3].
• Patients with glenohumeral arthritis often present with pain and stiffness, with the onset of symptoms occurring over years rather than the weeks to months seen in frozen shoulder [77].
• In the early stages of rheumatoid arthritis affecting the shoulder, common physical examination findings include localized warmth and limited range of motion with pain [26].
• In more chronic rheumatoid arthritis, crepitus and weakness may be encountered during physical examination [26].
• Periscapular atrophy may be noted during physical examination if an associated rotator cuff tear is present in patients with rheumatoid arthritis [26].
• Sternoclavicular or acromioclavicular joint tenderness occurs in about one-third of patients with glenohumeral involvement due to rheumatoid arthritis [26].
• Patients with rheumatoid arthritis commonly report generalized fatigue, pain in other joints, intermittent fever, and weight loss in their history [26].
• Pain, swelling, progressive loss of motion, and weakness are commonly seen in the affected shoulder of patients with rheumatoid arthritis [26].
• Rapidly destructive arthrosis of the shoulder joints should be considered in the differential diagnosis of elderly women with insidious shoulder pain [11].
• The manifestation of early glenohumeral arthritis in the young adult is described as a devastating occurrence [10].

Imaging and Diagnostic Evaluation

• A single true anteroposterior radiograph of the shoulder can differentiate idiopathic frozen shoulder from glenohumeral arthritis [77].
• Classic radiographic findings for inflammatory arthritis of the shoulder include osteopenia, marginal erosions, and cyst formation [26].
• Advanced inflammatory arthritis is characterized by concentric joint space narrowing and medial glenoid wear on radiography [26].
• Large, irreparable rotator cuff tears may result in superior migration of the humeral head, “acetabularization” of the acromion, and rounding of the greater tuberosity [26].
• CT should be performed when large bony defects or deformities are present in inflammatory arthritis [26].
• MRI is useful for evaluating the integrity of the rotator cuff tendons and muscle quality in inflammatory arthritis [26].
• A preoperative radiographic examination of the cervical spine is mandatory for patients with inflammatory arthritis to assess cervical spine stability before intubation [26].
• Increased age is the main determinant of radiological changes in shoulder osteoarthritis, as well as pain [34].
• F-18-FDG PET/CT effectively differentiates septic shoulder arthritis from varying stages of osteoarthritis [37].
• Plain radiographs at the advanced stage of septic arthritis can show changes from joint space narrowing and bone destruction, but these findings are insensitive and nonspecific in the early stage [63].
• Arthrocentesis may be helpful in the setting of an acutely painful shoulder to rule out septic arthritis and crystalline arthropathies [26].
• Milwaukee shoulder aspirates contain blood-tinged fluid with debris, hydroxyapatite crystals, and inflammatory cells with a preponderance of monocytes [26].
• The diagnosis of Milwaukee shoulder is confirmed by positive staining of the crystals with alizarin red [26].
• Gout can be diagnosed by the characteristic negatively birefringent, needle-shaped deposition of sodium urate crystals in joint fluid [26].
• Pseudogout joint fluid is characterized by positively birefringent, rhomboid-shaped calcium pyrophosphate dihydrate crystals [26].

Classification and Natural History

• Neer identified three types of shoulder rheumatoid arthritis based on radiographic findings: dry, wet, and resorptive [26].
• Dry shoulder rheumatoid arthritis is characterized by joint space narrowing, subchondral cysts, erosions with marginal osteophytes [26].
• Wet shoulder rheumatoid arthritis is characterized by marginal erosions and a pointed contour of the proximal humerus [26].
• Resorptive shoulder rheumatoid arthritis is characterized by rapid bone and cartilage loss with centralization of the glenohumeral joint to the level of the coracoid process [26].
• Shoulders presenting with posterior subluxation (B types) remained posteriorly subluxed over a decade, while concentric arthritis developed an eccentric pattern 20% of the time [33].
• Arthritic B2 glenoids are common, and their maximal erosion is usually posteroinferior [90].

Investigations

Plain Radiography

• The purpose of shoulder imaging is to help establish the diagnosis, determine the severity of the pathoanatomy, assist in surgical planning, and enable the surgeon to illustrate the condition of the shoulder to the patient [20].
• Standardized plain films are almost always sufficient to garner the information needed for shoulder arthritis care [20].
• The first key radiographic view is the anteroposterior (AP) view taken in the plane of the scapula such that the x-ray beam passes through the glenohumeral joint [20].
• The AP view in the plane of the scapula shows the superoinferior position of the humeral head relative to the glenoid, the presence of osteophytes on the humeral head and glenoid, narrowing of the joint space, and the degree of medial displacement of the humerus in relation to the lateral acromial line [20].
• The AP view also shows the quality of the humeral and glenoid bone, the presence of loose bodies, and whether there is humeral head collapse or deformity [20].
• The second key radiographic view is the axillary view taken with the arm in the functional position of elevation in the plane of the scapula [20].
• The axillary view is oriented so that both the spinoglenoid notch and the scapular neck are visible [20].
• The axillary view shows a different perspective of the humeral anatomy, the amount of glenoid bone, the shape of the glenoid, its version in relation to the plane of the scapula, and the relationship of the humeral head to the glenoid fossa [20].
• The axillary view is referred to as the “truth view” because it demonstrates the glenohumeral relationships in the functional position of elevation [20].
• CT scans have the disadvantage of being taken with the arm in the adducted position, whereas the axillary truth view is taken with the arm in elevation [20].
• Joint space narrowing is most evident on the axillary truth view as opposed to images made with the arm at the side [20].
• The axillary truth view can show posterior subluxation or “functional decentering” that is not evident in images taken with the arm at the side [20].
• The degree of posterior subluxation can be measured as the position of the center of the humeral head in relation to the plane of the scapula [20].
• The degree of posterior subluxation can be measured as the position of the center of the humeral head in relation to the glenoid face [20].
• The degree of posterior subluxation can be measured as the point of contact of the humeral articular surface on the glenoid articular surface [20].
• The point of contact of the humeral articular surface on the glenoid articular surface reflects the degree of centering of the net humeral joint reaction force on the glenoid [20].
• Malcentering of the joint reaction force leads to posterior instability, posterior glenoid wear, and “rocking horse” loosening of prosthetic glenoid components [20].
• Arthritis, calcific tendinitis, and osteolysis of the distal clavicle can be observed on plain radiograph [57].
• The critical shoulder angle is an effective radiographic parameter that is associated with rotator cuff tears and osteoarthritis [130].

Computed Tomography (CT)

• CT imaging is frequently used to assess for bony lesions in recurrent instability cases or for preoperative templating for shoulder arthritis [57].
• CT scans may offer a few degrees of increased precision in the measurement of glenoid version compared to plain films [20].
• Surgeons are not convinced that the increased precision of CT scans in measuring glenoid version improves the quality of the surgery or the clinical outcome [20].
• Three-dimensional CT reconstruction allows for reliable evaluation of the scapulohumeral relationship [132].
• 3D CT reconstruction reveals significant posterior translation of the humeral head in osteoarthritic shoulders compared to nonpathologic controls [132].
• The posterior translation of the humeral head in osteoarthritic shoulders supports the pathomechanism of glenoid component loosening [132].
• These data demonstrate an anatomic pattern of glenoid bone loss for different classes of glenohumeral arthritis [24].
• Pathoanatomic metrics with identified threshold values can be used to discriminate glenoid types in shoulders with primary glenohumeral osteoarthritis [32].
• Three significantly differently oriented wear patterns (posterior-superior, posterior-central, and posterior-inferior) were distinguished in shoulders demonstrating posterior wear on axillary imaging [136].

Magnetic Resonance Imaging (MRI)

• MRI is the modality of choice for evaluating the rotator cuff, biceps, and subacromial/subdeltoid bursa [57].
• T1-weighted MRI can reveal Hill-Sachs lesions and is often used with magnetic resonance arthrograms to provide a more detailed picture of the joint surfaces [57].
• T2-weighted MRI provides better visualization of full thickness rotator cuff tears [57].
• MRI is useful for preoperative osseous imaging for total shoulder arthroplasty because it offers a more precise method of determining glenoid version compared with x-ray imaging [101].

Arthrography

• Arthrography involves injection of contrast agent in conjunction with either an MRI or CT scan, enhancing imaging of the joint to enable better identification of normal structures and pathology involving the joint surfaces [57].
• MR arthrography is considered the benchmark for evaluation for labral tears and rarely is indicated for evaluation of rotator cuff pathology [57].
• When MRI or MR arthrography is contraindicated, CT arthrography is indicated [57].

Ultrasonography

• Ultrasonography is a low-cost alternative to MRI and arthrography for evaluating both skeletal and soft-tissue structures of the shoulder [57].
• Ultrasonography can provide immediate, real-time visualization of the rotator cuff, biceps tendon, and calcific deposits [57].
• Ultrasonography can be used to measure the subacromial space and detect atrophy of rotator cuff muscles [57].
• Ultrasonography can evaluate impingement in various positions and motions due to real-time imaging [57].
• Ultrasonography is highly operator dependent and is not as useful for evaluating labral tears or rotator cuff tears that are very small or larger than 3 cm [57].

General Imaging Principles

• The shoulder is a three-dimensional structure that cannot be represented by a single planar view [54].
• Critical relationships, such as the degree of centering of the humeral head, change with the position of the arm [54].
• Shoulder pathology may be found in a large number of different bones and soft tissues [54].
• Overlying and superimposed structures as well as metallic implants may complicate imaging the structures of interest [54].
• Surgeons need to develop a judicious approach to imaging that yields the information necessary to treat the patient while avoiding the tendency to "over-image" [54].
• Unless a specific research protocol is in place, the temptation to “overimage” should be resisted, obtaining only the scans or reconstructions that are necessary for the care of the patient [20].
• Proper radiographic technique is as important as proper surgical technique to achieve the desired outcome [20].
• The diagnosis of a stiff shoulder depends on awareness of the problem, with history and physical examination being paramount and ancillary studies helpful in certain circumstances [3].

Treatment

Non-Operative Management

• Initial treatment for shoulder arthritis typically consists of activity modification, anti-inflammatory medications, and physical therapy [23].
• Nonoperative treatment is the initial approach in almost all patients with a stiff shoulder [23].
• Injectable viscosupplementation is an additional nonoperative treatment option, although there is a paucity of evidence that supports its use in the shoulder [51].
• Injectable viscosupplementation is not currently approved by the U.S. Food and Drug Administration for injection in joints other than the knee [51].
• Nonoperative modalities should be utilized before surgical options, particularly for patients with moderate-to-mild disease [14].
• Any surgical treatment should be preceded by an adequate trial of conservative management that includes activity modification, physical therapy, anti-inflammatory medication, and corticosteroid injections [51].

Arthroscopic Management

• The American Academy of Orthopaedic Surgeons clinical practice guidelines classifies the use of arthroscopy for the treatment of glenohumeral arthritis as grade I, implying that they are unable to recommend for or against this option [51].
• A systematic review of the literature showed that arthroscopic debridement for glenohumeral arthritis lacks high-quality evidence to support its routine use [51].
• Arthroscopic treatment may be the best alternative when joint reconstruction is not desirable, possible, or practical [51].
• Arthroscopic intervention might be more suitable for elderly patients with significant medical comorbidities who might be unable to tolerate the stresses involved with a major surgery [51].
• A young patient who has developed early onset arthritis might not be the best candidate for total shoulder arthroplasty due to concerns related to prosthesis longevity and/or the high functional demands of the patient [51].
• Arthroscopy provides an opportunity to diagnose and treat coexistent soft tissue pathology in patients with osteoarthritis, perhaps eliminating the need for arthroplasty [51].
• The benefits of a lower complication rate and quicker return to normal activities after arthroscopy compared with total shoulder arthroplasty make arthroscopic treatment appealing in certain scenarios [51].
• The authors recommend a systematic, inclusive approach to the array of pathologies encountered in the setting of early glenohumeral arthritis: the Comprehensive Arthroscopic Management (CAM) procedure [30].

Arthroplasty: Anatomic Total Shoulder Arthroplasty (ATSA)

• Total shoulder arthroplasty is considered the gold standard for treating severe glenohumeral arthritis [51].
• Both keeled and pegged glenoid components yield similar pain relief, functional gains, and shoulder motion across most patient-reported outcome measures in total shoulder arthroplasty for primary osteoarthritis [12].
• There was no clinically or statistically significant difference in the Oxford Shoulder Score results between cemented and uncemented glenoid components in total shoulder arthroplasty for degenerative arthritis of the shoulder [129].
• Patients undergoing total shoulder arthroplasty with an asymmetric glenoid component for osteoarthritis achieve satisfactory mid-term pain relief and improvement in function; however, instability is not always corrected [96].
• Recent randomized controlled trials have reported clinical non-inferiority of stemless components relative to stemmed components in the setting of anatomic total shoulder arthroplasty [131].

Arthroplasty: Reverse Total Shoulder Arthroplasty (RTSA)

• Patients with glenohumeral osteoarthritis converted intraoperatively to reverse shoulder arthroplasty had outcomes comparable to those who underwent total shoulder arthroplasty [5].

Arthroplasty: Hemiarthroplasty and Resurfacing

• Total shoulder arthroplasty did not provide a clinically important advantage over hemiarthroplasty in terms of patient-reported pain, function, nor adverse effects; however, the evidence on this topic was of low quality [19].
• Cementless resurfacing arthroplasty (CSRA) provides good long-term symptomatic and functional results in the treatment of glenohumeral arthropathy in patients aged younger than 50 years in 81.6% of the patients [17].

General Treatment Considerations

• No treatment has proved to be definitive for shoulder arthritis [3].
• The literature supports many forms of treatment, both operative and nonoperative, for shoulder arthritis [3].
• The treatment approach for shoulder arthritis should be tailored to each individual patient to ensure the best possible outcome [3].
• Management strategies for shoulder arthritis, especially in young patients, continue to evolve with significant improvements in implant design, though longevity remains a concern in more active patients [2].
• Knowledge of the array of shoulder prostheses currently available and the indications for each, as well as the use of treatment algorithms, can lead to optimized patient outcomes [31].
• The present review highlights the need for standardization of outcome assessment following treatment of shoulder arthritis [1].
• The authors recommend the continued use of the Western Ontario Osteoarthritis of the Shoulder Index (WOOS) in shoulder arthroplasty registries and observational studies [15].

Complications

General Complication Rates and Timing

• The overall complication rate after total shoulder arthroplasty is estimated to be approximately 15% [97].
• Complications after total shoulder arthroplasty tend to occur late in the postoperative course, specifically 5 to 10 years after surgery [97].
• Component loosening has been reported to occur approximately 8 years after surgery [97].
• Infection has been reported to occur approximately 12 years after surgery [97].
• Periprosthetic fractures have been reported to occur approximately 6 years after surgery [97].
• A study of over 400 total shoulder arthroplasties done with cemented all-polyethylene glenoid components between 1990 and 2000 found a 12% complication rate [97].
• In the same study of cemented all-polyethylene glenoid components, only one reoperation was required because of component loosening [97].
• The most frequent complications in the review of cemented all-polyethylene glenoid components were rotator cuff tearing, glenohumeral instability, and periprosthetic humeral fracture [97].
• Revision surgery may be required in up to 3% to 10% of patients within two years of primary shoulder arthroplasty [122].

Specific Complication Frequencies (Unconstrained TSA)

• Component loosening occurred in 6.31% of shoulders in a review of 33 series (2540 shoulders) [95].
• Glenoid component loosening occurred in 5.3% of shoulders in a review of 33 series (2540 shoulders) [95].
• Humeral component loosening occurred in 1.1% of shoulders in a review of 33 series (2540 shoulders) [95].
• Instability occurred in 4.9% of shoulders in a review of 33 series (2540 shoulders) [95].
• Superior instability occurred in 3% of shoulders in a review of 33 series (2540 shoulders) [95].
• Posterior instability occurred in 1% of shoulders in a review of 33 series (2540 shoulders) [95].
• Anterior instability occurred in 0.9% of shoulders in a review of 33 series (2540 shoulders) [95].
• Periprosthetic fracture occurred in 1.8% of shoulders in a review of 33 series (2540 shoulders) [95].
• Intraoperative periprosthetic fracture occurred in 1.1% of shoulders in a review of 33 series (2540 shoulders) [95].
• Postoperative periprosthetic fracture occurred in 0.7% of shoulders in a review of 33 series (2540 shoulders) [95].
• Rotator cuff tear occurred in 1.3% of shoulders in a review of 33 series (2540 shoulders) [95].
• Neural injury occurred in 0.8% of shoulders in a review of 33 series (2540 shoulders) [95].
• Infection occurred in 0.7% of shoulders in a review of 33 series (2540 shoulders) [95].
• Deltoid detachment occurred in 0.08% of shoulders in a review of 33 series (2540 shoulders) [95].

Reverse Total Shoulder Arthroplasty Complications

• Reverse total shoulder arthroplasty initially resulted in relatively high complication rates of 50% [97].
• With improved techniques and better understanding of the device, the complication rate for reverse total shoulder arthroplasty has fallen to 6% recently reported [97].
• The most common complications after reverse total shoulder arthroplasty are scapular notching, hematoma formation, glenoid dissociation such as baseplate failure or aseptic loosening, glenohumeral dislocation, acromial and scapular spine fractures, infection, loosening or dissociation of the humeral component, and nerve injury [97].
• Complication rates are higher and functional improvement more modest when reverse shoulder arthroplasty is performed as a revision of a prior arthroplasty [108].
• Infection is one of the most common modes of failure following reverse total shoulder arthroplasty [108].
• Propionibacterium species is a frequently cultured organism from failed reverse total shoulders, which can present with loosening in the absence of the usual clinical signs of infection [108].
• Instability following reverse total shoulder arthroplasty can result from falls, suboptimal component selection, component malposition, bulky tissues in the posterior shoulder, leverage of the humeral component against the glenoid, or lack of a sufficient compressive effect by the deltoid [108].
• The risk of humeral fracture is increased by revision surgery and by falls [108].
• The risk of humeral fracture is also increased when the humeral component fixation results in an abrupt transition between a cemented or press-fitted diaphyseal stem tip and osteopenic bone distal to the stem [108].

Anatomic Total Shoulder Arthroplasty Complications

• Total shoulder arthroplasty may have reasonable short-term results but is associated with high mid-term complication rates due to instability and loosening in B2 glenoids [86].
• Symptomatic acromioclavicular joint osteoarthritis occurred in 15.9% of patients after total anatomic shoulder replacement with follow-up of up to 12 years [27].
• The primary causes of failure of the cuff tear arthropathy (CTA) prosthesis are weakness and instability [108].
• Maintaining the integrity of the subscapularis appears to be important to the outcome of cuff tear arthropathy prosthesis [108].

Risk Factors and Patient-Specific Complications

• Morbidly obese patients are known to have a higher rate of medical complications and to incur higher costs [107].
• Diabetes is reported to correlate with a higher rate of perioperative medical complications [107].
• Hepatitis C has been established as an independent factor correlating with increased complications, including infection and need for revision [107].
• Perioperative mortality for shoulder arthroplasty is only approximately 1% [107].
• Age below 65 years (HR 2.63) was significantly associated with an increased risk of revision [123].
• Previous shoulder surgery (HR 2.00) was significantly associated with an increased risk of revision [123].
• Prior nonshoulder periprosthetic joint infection increases the risk of surgical site infection, sepsis, and all-cause revision after primary total shoulder arthroplasty [122].

Management and Diagnosis of Complications

• Most nerve injuries following shoulder arthroplasty are neurapraxias that recover with time [95].
• A complete neurologic examination should be done early in the postoperative period to document any nerve deficits [95].
• If no recovery is noted after 6 weeks, an electromyographic examination should be obtained and should be repeated at 3 months [95].
• If no recovery has occurred as evident by electromyography at 3 months, exploration of the nerve should be considered [95].
• If malposition of the humerus is noted with an uncemented component, it can typically be disimpacted and repositioned [95].
• If a cemented component is used, an offset humeral head prosthesis can be used to attempt to correct version [95].
• The offset humeral head allows 5 to 7 degrees of version correction in the anterior or posterior direction [95].
• A malpositioned cemented humeral stem often requires a lengthy and difficult revision procedure to remove the well-fixed component and replace it in an appropriate position [95].
• Early closed reduction can be successful for instability following reverse total shoulder arthroplasty [108].
• Recurrent or chronic instability following reverse total shoulder arthroplasty may require surgical revision [108].
• Stability may be restored by changing to a larger diameter of curvature and increasing the thickness of the polyethylene humeral cup [108].

Recovery

Non-Operative Management

• Initial treatment for a stiff shoulder is usually conservative, consisting of activity modification, antiinflammatory medications, and physical therapy [23].
• Nonoperative treatment options include oral medications, physical therapy, injections, or other modalities [23].
• Most patients with frozen shoulder present to their physician expecting a diagnosis and a treatment plan to expedite recovery [23].
• Many patients are not willing to accept that it may take 2 years for significant resolution of frozen shoulder symptoms [23].
• There is a consensus that some form of treatment, nonoperative or operative, is indicated in any patient with a stiff shoulder [23].

Operative Management

• When patients fail to respond to nonoperative treatment for a stiff shoulder, operative intervention may be indicated [23].
• Operative interventions for a stiff shoulder include manipulation under anesthesia, surgical release (open or arthroscopic), or some combination of these two treatments [23].
• Many recent publications have focused on the efficacy of arthroscopic procedures to treat frozen shoulder, with promising results [23].
• No treatment has proved to be definitive for a stiff shoulder [3].
• The literature supports many forms of treatment, both operative and nonoperative, for a stiff shoulder [3].
• The treatment approach for a stiff shoulder should be tailored to each individual patient to ensure the best possible outcome [3].

Post-Arthroplasty Outcomes and Complications

• At a mean of 41 month follow-up, primary anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty patients with osteoarthritis and an intact rotator cuff with no previous history of shoulder surgery had similar clinical and radiographic outcomes [38].
• Patients in the proximal humerus fracture cohort were less likely to report persistent shoulder pain at all evaluated time points compared to the osteoarthritis cohort [43].
• At 3 years' follow-up, pain and clinical scores improved significantly and no case of glenoid loosening occurred in revision arthroplasty with a hip-inspired computer-assisted design/computer-assisted manufacturing implant for glenoid-deficient shoulders [36].

Long-Term Implant Results

• Constrained shoulder resurfacing arthroplasty provides good long-term symptomatic and functional results in the treatment of glenohumeral arthropathy in patients aged younger than 50 years in 81.6% of the patients [17].
• Shoulder arthritis management strategies, especially in young patients, continue to evolve with significant improvements in implant design, though longevity remains a concern in more active patients [2].

Assessment and Prognosis

• The PROMIS Global-10 appears to have limited utility in the evaluation of patients with shoulder arthritis both preoperatively and after total shoulder arthroplasty [137].
• Frozen shoulder is a common epidemiological affliction that does not resolve spontaneously in a large number of patients [4].
• It is important to understand the natural history of a stiff shoulder so that patients are well informed and can actively participate in decision-making [3].

Key Evidence

• [L1] The present review highlights the need for standardization of outcome assessment following treatment of shoulder arthritis. [1] (10.1177/1758573215622385)
• [L5] Shoulder arthritis is common, and management strategies, especially in young patients, continue to evolve with significant improvements in implant design, though longevity remains a concern in more active patients. [2] (10.1016/j.csm.2018.07.001)
• [L4] Frozen shoulder is a common epidemiological affliction that does not resolve spontaneously in a large number of patients. [4] (10.3389/fmed.2021.663703)
• [L3] Patients with glenohumeral osteoarthritis converted intraoperatively to RSA had outcomes comparable to those who underwent total shoulder arthroplasty. [5] (10.1016/j.jse.2015.01.005)
• [L4] Reverse shoulder arthroplasty provides optimal outcomes with low complication rates across a short term of follow-up for glenohumeral osteoarthritis with an intact rotator cuff. [6] (10.1016/j.jse.2021.06.010)
• [L4] Primary glenohumeral osteoarthritis is associated with distinct global scapular morphologic characteristics. [7] (10.1016/j.jse.2026.06.017)
• [Paper] Patients with mild radiographic signs of arthritis have about sevenfold higher odds of failing to achieve the minimum clinically important difference (MCID) after anatomic total shoulder replacement compared to patients with severe arthritis. [8] (10.1097/corr.0000000000002747)
• [L1] A clear standardised set of shoulder arthroplasty complication definitions is lacking. [9] (10.1007/s00402-017-2635-9)
• [Paper] [10] (10.1016/j.csm.2018.05.002)
• [L4] This condition should be considered in the differential diagnosis of elderly women with insidious shoulder pain. [11] (10.1016/j.jse.2014.10.020)
• [L2] Both designs yield similar pain relief, functional gains, and shoulder motion across most patient-reported outcome measures. [12] (10.5397/cise.2025.01480)
• [L5] The article provides an overview of available treatments for shoulder osteoarthritis, noting that nonoperative modalities should be utilized before surgical options, particularly for patients with moderate-to-mild disease, while surgical treatments like arthroplasty are considered effective for severe cases. [14] (10.1155/2013/370231)
• [L4] The authors recommend the continued use of WOOS in shoulder arthroplasty registries and observational studies. [15] (10.1186/s12891-023-06578-5)
• [L4] CSRA provides good long-term symptomatic and functional results in the treatment of glenohumeral arthropathy in patients aged younger than 50 years in 81.6% of the patients. [17] (10.1016/j.jse.2014.11.035)
• [L4] [18] (10.1177/23259671261451245)
• [L1] Total shoulder arthroplasty did not provide a clinically important advantage over hemiarthroplasty in terms of patient-reported pain, function, nor adverse effects; however, the evidence on this topic was of low quality. [19] (10.1097/corr.0000000000001523)
• [L4] These data demonstrate an anatomic pattern of glenoid bone loss for different classes of glenohumeral arthritis. [24] (10.1007/s12306-016-0406-3)
• [L4] Symptomatic ACJ OA occurred in 15.9% of patients after total anatomic shoulder replacement with follow-up of up to 12 years. [27] (10.1177/17585732221114796)
• [L4] The authors recommend a systematic, inclusive approach to the array of pathologies encountered in the setting of early glenohumeral arthritis: the Comprehensive Arthroscopic Management (CAM) procedure. [30] (10.1016/j.arthro.2022.01.033)
• [L5] Knowledge of the array of shoulder prostheses currently available and the indications for each, as well as the use of treatment algorithms, can lead to optimized patient outcomes. [31] (10.5435/00124635-200907000-00002)
• [L4] Pathoanatomic metrics with the identified threshold values can be used to discriminate glenoid types in shoulders with primary glenohumeral osteoarthritis. [32] (10.1016/j.jse.2021.03.140)
• [L4] Shoulders presenting with posterior subluxation (B types) remained posteriorly subluxed, while concentric arthritis developed an eccentric pattern 20% of the time. [33] (10.1016/j.jse.2020.05.021)
• [L3] This study shows that increased age is the main determinant of radiological changes in shoulder OA, as well as pain. [34] (10.1186/s13018-022-03137-x)
• [L4] At 3 years' follow-up, pain and clinical scores improved significantly and no case of glenoid loosening occurred. [36] (10.1016/j.jse.2013.05.004)
• [L3] F-18-FDG PET/CT effectively differentiates septic shoulder arthritis from varying stages of osteoarthritis. [37] (10.1016/j.jse.2025.01.047)
• [L3] At a mean of 41 month follow-up, primary aTSA and rTSA patients with OA and an intact rotator cuff with no previous history of shoulder surgery had similar clinical and radiographic outcomes. [38] (10.5435/jaaos-d-22-00014)
• [L3] Both augmented and standard anatomic total shoulder arthroplasty can provide satisfactory and sustained improvements in patient-reported outcomes in patients with acquired glenoid retroversion due to glenohumeral osteoarthritis. [39] (10.1016/j.jse.2021.12.016)
• [L3] [41] (10.1016/j.jse.2023.07.027)
• [L3] Patients in the proximal humerus fracture (PHF) cohort were less likely to report persistent shoulder pain at all evaluated time points compared to the osteoarthritis (OA) cohort, suggesting that symptom relief following treatment of traumatic pathology may differ fundamentally from that of chronic degenerative disease. [43] (10.1016/j.jsea.2026.100012)
• [L3] The 3D classification system using combined humeroscapular alignment and glenoid erosion can be applied to describe the disease comprehensively. [59] (10.1177/23259671221110512)
• [L3] [63] (10.1016/j.jse.2019.05.010)
• [Paper] Current classifications exhibit poor reliability in categorizing glenoid defects post-reverse shoulder arthroplasty removal. [67] (10.1016/j.jseint.2024.08.170)
• [L3] A small lateral extension and less posterior rotation of the acromion is associated with shoulder osteoarthritis and is present in almost all types and subtypes of glenoid morphology. [75] (10.1016/j.jse.2021.01.018)
• [L5] Total shoulder arthroplasty may have reasonable short-term results but is associated with high mid-term complication rates due to instability and loosening in B2 glenoids. [86] (10.1016/j.jse.2013.06.017)
• [L4] Arthritic B2 glenoids are common, and their maximal erosion is usually posteroinferior. [90] (10.1016/j.jse.2015.01.007)
• [L4] Patients undergoing total shoulder arthroplasty with an asymmetric glenoid component for osteoarthritis achieve satisfactory mid-term pain relief and improvement in function; however, instability is not always corrected. [96] (10.1007/s11999-007-0104-4)
• [L3] MRI is useful for preoperative osseous imaging for total shoulder arthroplasty because it offers a more precise method of determining glenoid version compared with x-ray imaging. [101] (10.1016/j.jse.2012.10.036)
• [L4] Osteoarthritic humeral head morphology varies significantly from normal, with larger spherical diameters, but does not vary as a function of the Walch classification between symmetric and asymmetric glenoids. [106] (10.1016/j.jse.2015.08.047)
• [L4] [109] (10.1016/j.jse.2017.01.027)
• [L3] [120] (10.1016/j.jse.2016.07.007)
• [L3] [122] (10.5435/jaaos-d-21-00745)
• [L3] Age below 65 years (HR 2.63) and previous shoulder surgery (HR 2.00) were also significantly associated with an increased risk of revision. [123] (10.1016/j.jseint.2025.101482)
• [L3] There was no clinically or statistically significant difference in the Oxford Shoulder Score results between the two groups. [129] (10.1016/j.jse.2013.08.022)
• [L4] The CSA is an effective radiographic parameter that is associated with rotator cuff tears and osteoarthritis. [130] (10.1136/jisakos-2018-000255)
• [Paper] The discussion notes that recent randomized controlled trials have reported clinical non-inferiority of stemless components relative to stemmed components in the setting of anatomic total shoulder arthroplasty. [131] (10.1016/j.eats.2023.07.009)
• [L4] The study demonstrates that 3D CT reconstruction allows for reliable evaluation of the scapulohumeral relationship, revealing significant posterior translation of the humeral head in osteoarthritic shoulders compared to nonpathologic controls, which supports the pathomechanism of glenoid component loosening. [132] (10.1016/j.jse.2016.02.035)
• [L4] Three significantly differently oriented wear patterns (posterior-superior, posterior-central, and posterior-inferior) were distinguished in shoulders demonstrating posterior wear on axillary imaging. [136] (10.1016/j.jse.2021.04.028)
• [L3] The Global-10 appears to have limited utility in the evaluation of patients with shoulder arthritis both preoperatively and after TSA. [137] (10.1016/j.jse.2020.10.021)

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[16] Chapter 25 Shoulder Arthritis and Arthroplasty. 2020.

[17] Surface replacement arthroplasty for glenohumeral arthropathy in patients aged younger than fifty years: results after a minimum ten-year follow-up. Journal of Shoulder and Elbow Surgery. 2015. DOI: 10.1016/j.jse.2014.11.035

[18] Rate of Shoulder Arthroplasty After Anterior Shoulder Instability Surgery: A Systematic Review. Orthopaedic Journal of Sports Medicine. 2026. DOI: 10.1177/23259671261451245

[19] Cochrane in CORR®: Shoulder Replacement Surgery For Osteoarthritis And Rotator Cuff Tear Arthropathy. Clinical Orthopaedics & Related Research. 2020. DOI: 10.1097/corr.0000000000001523

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[23] Rockwood And Matsen S The Shoulder. Arthroscopic Management of Prearthritic and Arthritic Conditions of the Shoulder and the Postarthroplasty Shoulder > TREATMENT.

[24] Quantitative assessment and characterization of glenoid bone loss in a spectrum of patients with glenohumeral osteoarthritis. MUSCULOSKELETAL SURGERY. 2016. DOI: 10.1007/s12306-016-0406-3

[26] Aaos Comprehensive Orthopaedic Review 3. Arthritis and Arthroplasty of the Shoulder* > II. Inflammatory Arthritis.

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[29] Classifications And Scores Of The Shoulder. 15.1 Variations in Involvement in rheumatoid arthritis [102]*.

[30] Comprehensive Arthroscopic Management of Shoulder Arthritis. Arthroscopy. 2022. DOI: 10.1016/j.arthro.2022.01.033

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[32] Identification of threshold pathoanatomic metrics in primary glenohumeral osteoarthritis. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2021.03.140

[33] Natural history of glenoid bone loss in primary glenohumeral osteoarthritis: how does bone loss progress over a decade?. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2020.05.021

[34] Radiological changes in shoulder osteoarthritis and pain sensation correlate with patients’ age. Journal of Orthopaedic Surgery and Research. 2022. DOI: 10.1186/s13018-022-03137-x

[36] Revision arthroplasty with a hip-inspired computer-assisted design/computer-assisted manufacturing implant for glenoid-deficient shoulders. Journal of Shoulder and Elbow Surgery. 2014. DOI: 10.1016/j.jse.2013.05.004

[37] 18F-FDG PET/CT for the diagnosis of septic shoulder arthritis: metabolic uptake pattern and diagnostic performance. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2025.01.047

[38] Comparison of Reverse and Anatomic Total Shoulder Arthroplasty in Patients With an Intact Rotator Cuff and No Previous Surgery. Journal of the American Academy of Orthopaedic Surgeons. 2022. DOI: 10.5435/jaaos-d-22-00014

[39] Mid- to long-term outcomes of augmented and nonaugmented anatomic shoulder arthroplasty in Walch B3 glenoids. Journal of Shoulder and Elbow Surgery. 2022. DOI: 10.1016/j.jse.2021.12.016

[41] Reverse shoulder arthroplasty for primary glenohumeral osteoarthritis: significantly different characteristics and outcomes in shoulders with intact vs. torn rotator cuff. Journal of Shoulder and Elbow Surgery. 2024. DOI: 10.1016/j.jse.2023.07.027

[43] Complication rates following total shoulder arthroplasty for osteoarthritis versus proximal humerus fracture: a propensity-matched cohort comparison of 9,190 patients. Journal of Shoulder and Elbow Arthroplasty. 2026. DOI: 10.1016/j.jsea.2026.100012

[44] Rockwood And Matsen S The Shoulder. Shoulder and Elbow Specialty Clinic Workers’ Survey > ANATOMY.

[46] A Lange Medical Book Current Diagnosis Treatment In Orthopedics Fifth Edition. 2Musculoskeletal Trauma Surgery > SHOULDER AND ARM INJURIES.

[47] Aaos Comprehensive Orthopaedic Review 3. Anatomy of the Shoulder, Arm, and Elbow > I. Shoulder.

[48] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > Bursae.

[50] Rockwood And Matsen S The Shoulder. Developmental Anatomy of the Shoulder and Anatomy of the Glenohumeral Joint > EDITOR COMMENTARY.

[51] Rockwood And Matsen S The Shoulder. Arthroscopic Management of Prearthritic and Arthritic Conditions of the Shoulder and the Postarthroplasty Shoulder > INDICATIONS FOR ARTHROSCOPIC TREATMENT.

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[59] A 3-Dimensional Classification for Degenerative Glenohumeral Arthritis Based on Humeroscapular Alignment. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/23259671221110512

[63] Treatment of acute shoulder infection: can osseous lesion be a rudder in guideline for determining the method of débridement?. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2019.05.010

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[67] Glenoid Defects In Revision Reverse Shoulder Arthroplasty: Are Current Classification Systems Appropriate?. JSES International. 2024. DOI: 10.1016/j.jseint.2024.08.170

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[70] Rockwood And Matsen S The Shoulder. Fractures, Dislocations, and Acquired Problems of the Shoulder in Children > Tendon Healing.

[75] Determination of predisposing scapular anatomy with a statistical shape model—Part II: shoulder osteoarthritis. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2021.01.018

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[86] Current concepts in the surgical management of primary glenohumeral arthritis with a biconcave glenoid. Journal of Shoulder and Elbow Surgery. 2013. DOI: 10.1016/j.jse.2013.06.017

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[109] Interest in the glenoid hull method for analyzing humeral subluxation in primary glenohumeral osteoarthritis. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2017.01.027

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[120] Glenoid deformity in the coronal plane correlates with humeral head changes in osteoarthritis: a radiographic analysis. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2016.07.007

[122] Prior Nonshoulder Periprosthetic Joint Infection Increases the Risk of Surgical Site Infection, Sepsis, and All-Cause Revision After Primary Total Shoulder Arthroplasty. Journal of the American Academy of Orthopaedic Surgeons. 2021. DOI: 10.5435/jaaos-d-21-00745

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