summary Glenohumeral arthritis, or Shoulder Arthritis, is a degenerative joint disease of the shoulder characterized by damage to the articular surfaces of the humeral head and/or glenoid. Diagnosis is made radiographically with true AP shoulder ("Grashey") and axillary lateral radiographs. Treatment is observation, NSAIDs, and corticosteroids for minimally symptomatic patients. Shoulder arthroplasty is indicated for progressive symptoms with severe degenerative disease. Epidemiology Incidence increases with age more likely in patients over 60 Demographics more common in women Risk factors 56% of patients who had primary anterior dislocation have arthrosis at 25 years follow up Etiology Causes primary osteoarthritis secondary arthritis post-traumatic arthritis of dislocation inflammatory/crystalline arthritis osteonecrosis neuropathic (Charcot Arthropathy) rotator cuff arthropathy Pathophysiology primary osteoarthritis articular cartilage irreversible progressive loss of articular cartilage with hypertrophic reaction of the subchondral bone; no known cause humeral head thinning/absence of cartilage, flattening, osteophyte and subchondral cyst formation, posterior humeral subluxation glenoid posterior wear (see: Walch glenoid classification), subchondral cyst formation rotator cuff rotator cuff tears incidence 5-10%, important to rule out post-traumatic arthritis articular surface incongruities following trauma healing can lead to joint deterioration commonly occurs in patients with humeral fractures and chronic dislocations cuff tear arthropathy torn rotator cuff tendons leads to humeral head migration and subsequent abrasive contact between the humeral head and acromion which leads to articular wear dislocation arthropathy repeated dislocation can cause erosion of joint cartilage higher incidence with increased age posterior dislocation not associated with number of dislocations post-capsulorraphy arthropathy excessive tightening of soft tissues in stabilization surgeries to treat recurrent dislocation forces humeral head in one direction causes head to wear unevenly on glenoid inflammatory/crystalline arthritis rheumatoid arthritis systemic autoimmune disease causes synovial inflammation and degradation of shoulder joint can involve all structures of shoulder including soft tissue affects 90% of patient with RA characterized by central glenoid wear and medialization of humeral head calcium pyrophosphate dihydrate deposition disease (CPPD) accumulation of calcium pyrophosphate crystals within joint space causing synovial inflammatory response and cartilage/bone damage; sometimes referred to as “pseudogout” gout accumulation of sodium urate crystals within joint due to hyperuricemia causing inflammatory attack within joint and cartilage/bone damage osteonecrosis/avascular necrosis bone cell death caused by interruption of blood supply to humeral head leads to subchondral bone collapse and morphological/arthritic changes causes traumatic proximal humerus fractures 35% incidence in 3-part 90% incidence in 4-part chronic glenohumeral dislocations repetitive injury rotator cuff repair atraumatic steroid ETOH hemoglobinopathies metabolic (e.g. Gaucher’s disease chondrolysis occurs following shoulder arthroscopy exact pathophysiology unknow but associated with radiofrequency energy continuous postop anesthetic infusion bioabsorbable suture anchors contrast leads to the dissolution of articular cartilage has less osteophytes than OA Associated conditions rotator cuff tears 5-10% incidence with OA 25-50% incidence with RA Anatomy Glenohumeral (GH) joint joint comprised of humeral head and glenoid fossa of scapula stability static restraints glenohumeral ligaments glenoid labrum dynamic restraints rotator cuff muscles rotator interval biceps Glenoid osteology glenoid is 3 degreees retroverted humerus is 20-30 degrees retroverted Classification Walch Classification of Glenoid Wear Type A Concentric wear, no subluxation of HH, well centered A1: no or minor central erosion A2: deeper central erosion, line connects anterior/posterior glenoid rims and transects humeral head (HH) Type B Biconcave glenoid, asymmetric glenoid wear and head subluxated posteriorly B0: pre-osteoarthritic posterior subluxation of HH B1: posterior joint narrowing (no posterior bone loss), osteophytes, subchondral sclerosis B2: posterior rim erosion, retroverted glenoid B3: mono-concave, posterior wear, at least HH subluxation >70% OR retroversion >15 degrees Type C C1: Glenoid retroversion >25 degrees, regardless of erosion C2: Biconcave, posterior bone loss, posterior translation of HH Type D Glenoid anteversion or anterior HH subluxation (HH subluxation <40%) Presentation Symptoms shoulder pain worse with activities involving shoulder motion often no pain at rest loss of range of motion especially external rotation due to anterior capsule contraction difficulty sleeping Physical exam functional limitations at glenohumeral joint decreased external rotation, forward flexion, and internal rotation variable and more active patients have better range of motion (ROM) crepitus catching/squeaking with articulation motor a carefully evaluation of the rotator cuff muscles should be performed Functional Outcomes Scores ASES Shoulder Score Constant Score Oxford Shoulder Score Imaging Radiographs recommended views true anteroposterior (AP) of GH joint AP axillary lateral findings often diagnose etiology primary osteoarthritis joint space narrowing subchondral sclerosis, subchondral cysts osteophytes circumferentially at humeral head, “goat’s beard” posterior glenoid wear fixed posterior humeral head subluxation (due to tight anterior capsule) post-traumatic arthritis articular surface incongruities due to healed fractures hardware from previous surgeries arthritis of dislocation large osteophytes hardware from previous surgery inflammatory/crystalline arthritis RA joint space narrowing marginal erosions of humeral head reduction in acromiohumeral distance few osteophytes central glenoid wear and medialization of humeral head osteopenia CPPD chondrocalcinosis (calcific deposits in articular/fibrocartilage) Gout usually unremarkable repeat attacks may show osteopenia/erosions osteonecrosis/avascular necrosis normal radiographs early in disease resorption of middle of humeral head crescent sign (lucency) indicating subchondral collapse flattening/collapse in more advanced stages rotator cuff tear arthropathy osteopenia superior migration of humeral head narrowing of acromiohumeral interval acromial erosions superior glenoid bone loss “acetabularization” of coracoacromial arch Computed tomography (CT) indications evaluate glenoid morphology and rotator cuff pathology for pre-operative planning may underestimate full-thickness RCTs and fatty infiltration/muscle atrophy compared to MRI allows for pre-operative templating Magnetic Resonance Imaging (MRI) indications evaluate rotator cuff pathology for pre-operative planning less accurate than CT in distinguishing between glenoid types Treatment Nonoperative physical therapy, NSAIDs indications first-line of treatment modalities NSAIDs- reduce pain and inflammation physical therapy – improve range of motion with capsular stretching intraarticular Injections indications second-line of treatment modality corticosteroid injection – reduce pain/inflammation hyaluronic acid injection – joint lubrication, limited evidence biologics (platelet rich plasma, stem cell) – limited evidence DMARDs indications rheumatoid arthritis Operative total shoulder arthroplasty (TSA) indications intact rotator cuff unresponsive to non-operative treatment glenoid chondral wear posterior humeral head subluxation contraindications lack of deltoid or rotator cuff function active infection Charcot arthropathy technique concave glenoid (cup) and convex humerus (ball) to reconstruct joint outcomes good pain relief, reliable ROM 10 year survival (92-95%) most common complications: glenoid/humeral component loosening, infection, fracture, nerve injury and rotator cuff tear higher risk of prosthetic joint infection when performed within 3 months of prior arthroscopic procedure hemiarthroplasty indications younger patient rheumatoid arthritic patients with irreparable RC tears/insufficient bone stock osteonecrosis without glenoid involvement technique humeral head replacement ± biologic resurfacing ream-and-run technique humeral head prosthesis & glenoid reaming to provide a stabilizing concavity and maximize glenohumeral contact area for load transfer indicated in young patients with intact rotator cuff and no inflamatory arthropathy outcomes early failure rate, not recommended poor pain and functional outcomes reverse shoulder arthroplasty (RSA) indications irreparable/large rotator cuff tear OA or RA with significant glenoid pathology age rotator cuff arthropathy failed arthroplasty complex fracture technique convex glenoid (ball) and concave humerus (cup) to reconstruct joint outcomes Good pain relief, improved shoulder function 10 year survival (~90-95%) Common complications: scapular notching, infection, dislocation/instability, nerve injuries; higher reported complication rates than TSA arthroscopic debridement indications mild to moderate OA without structural alternation mechanical symptoms due to loose bodies or small lesions of humeral head due to AVN synovial chondromatosis outcomes temporizing treatment; improves ROM and pain less successful in those with more rapid degenerative changes higher rates of failure in those with more preoperative joint space narrowing and posterior glenoid wear may see better results in patients who also had subacromial procedures CAM (comprehensive arthroscopic management) procedure indications younger patient technique combination of arthroscopic glenohumeral debridement, chondroplasty, synovectomy, loose body removal, humeral osteoplasty with excision of the goat's beard osteophyte, capsular releases, subacromial and subcoracoid decompressions, axillary nerve decompression, and biceps tenodesis arthrodesis indications paralysis recurrent infection severe soft tissue deficiency; poor deltoid function brachial plexus palsy persistent symptomatic instability with failed repair outcomes moderate complications Improved/ acceptable long-term function Techniques Total shoulder arthroplasty Hemiarthroplasty Reverse ball prosthesis