Osteoarthritis (OA) of the Glenohumeral Joint

Background

• Glenohumeral joint OA involves a gradual breakdown of articular cartilage, accompanied by osteophyte formation, subchondral sclerosis, and synovial proliferation, resulting in shoulder pain and stiffness.
• Types of glenohumeral OA consist of primary and secondary.
  • In primary OA the cause is unknown, commonly occurring in patients ≥ 60 years old.
  • In secondary OA the cause is known and typically involves trauma, chronic inflammation, or atraumatic osteonecrosis in patients < 60 years old.
• Risk factors include previous shoulder trauma, chronic rotator cuff tear, joint infection, older age (> 65 years), White race, female sex, and obesity.

Evaluation

• Suspect glenohumeral OA in patients with the following signs and symptoms:
  • chronic shoulder pain, particularly in patients > 50 years old
  • shoulder pain at night, which may interfere with sleep
  • stiffness that worsens with activity and improves with rest
  • swelling and joint enlargement
  • tenderness deep in the shoulder joint, often felt posteriorly
  • decreased mobility of the shoulder, particularly in external rotation and abduction
• X-ray is used to confirm diagnosis; findings may include
  • narrowing of joint space with central, posterior, and/or superior erosion (posterior glenoid erosion most common in primary OA)
  • osteophytes
  • subchondral sclerosis
  • cysts
  • eburnation
  • abnormal glenoid version
  • humeral subluxation (commonly observed as superior humeral head migration)
• Advanced imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), are typically not needed; however, may be used to aide in
  • preoperative planning
  • OA staging
  • identifying concomitant labral and rotator cuff damage
  • evaluation of patients with secondary glenohumeral OA due to causes such as avascular necrosis, and infectious or crystalline arthropathies

Management

• Nonoperative management of glenohumeral OA should be tried initially in all patients.
  • Early changes should include lifestyle and activity modifications, such as avoiding activities that involve load-bearing through or impact on affected shoulder.
  • Pharmacological therapy is generally used for control of pain and inflammation.
    • Analgesics:
      • Consider acetaminophen 3-4 g/day as initial medication for pain relief.
      • Nonsteroidal anti-inflammatory drugs (NSAIDs) and COX-2 inhibitors may also be considered for pain relief if acetaminophen is inadequate.
      • Opioids may be considered for brief periods in patients with poor pain control; however, consider avoiding opioids for routine or long-term pain management (Weak recommendation).
    • Corticosteroid injections:
      • For patients with persistent pain who are not responding to oral medications, consider intra-articular corticosteroid injections.
      • Corticosteroid injections may be of particular benefit if administered at start of physical therapy program.
  • Physical therapy is typically incorporated into a multidisciplinary, nonoperative treatment regimen to help reduce pain, and improve range of motion and function.
    • Physical therapy may be particularly beneficial in
      • young patients who are not good candidates for arthroplasty due to implant survivorship concerns
      • older patients who are not surgical candidates due to comorbidities
      • patients who prefer nonoperative management
    • Considerations for physical therapy regimen:
      • Consensus is lacking regarding optimal intensity and duration of therapy.
      • Therapeutic exercise generally includes stretching and strengthening of the shoulder region.
      • Modalities may be used to help manage symptoms, including heat, electrotherapy, low level laser therapy, and ultrasound.
      • Patient education is provided to help reinforce the importance of lifestyle and activity modifications, and adherence to the exercise program.
• Operative management may be considered in patients with severe glenohumeral OA that is recalcitrant to nonoperative measures or causing substantial functional limitations.
  • Arthroscopic techniques are used with goal of reducing symptoms while preserving the native joint.
    • Despite the limited evidence of efficacy, arthroscopic techniques are frequently considered in patients who have failed nonoperative management and either of the following:
      • have early stages of degeneration and wish to maintain mobility
      • are younger in age (< 55-60 years old) and could outlive the survival of a prosthetic implant
    • Determination of what arthroscopic techniques are used depends on what pathologies are identified during testing.
  • Arthroplasty options include total shoulder arthroplasty, reverse shoulder arthroplasty, and hemiarthroplasty.
    • Total shoulder arthroplasty (replacement of humeral head and glenoid) is typically indicated if all of the following:
      • age > 50 years
      • pain and loss of shoulder function which is unresponsive to nonoperative management
      • physical exam findings that correlate with symptoms
      • intact or reparable rotator cuff
      • x-ray findings of glenohumeral OA and adequate glenoid bone stock
      • free from medical comorbidities which would preclude joint replacement surgery
      • expected compliance with postoperative activity restrictions and rehabilitation regimen
      • patient accepts risks of surgery
    • Reverse shoulder arthroplasty (involves attaching a prosthetic humeral head in the glenoid socket and prosthetic glenoid cup on the upper humerus) indications include
      • irreparable rotator cuff injury
      • rotator cuff arthropathy
      • severe glenoid bone loss or a biconcave glenoid
      • failed previous arthroplasty
    • Hemiarthroplasty (involves use of a stemmed or stemless humeral prosthesis, either alone or in combination with glenoid resurfacing) indications include
      • younger patients with OA involvement primarily confined to the humeral head, with a relatively preserved glenoid
      • patients with glenoid bone stock that is inadequate for supporting a glenoid prosthesis