What is the appropriate treatment for a patient with a 2-month history of right shoulder pain, moderate narrowing and arthritic change at the acromioclavicular (AC) joint, and a tiny bony irregularity over the greater tuberosity of the humerus?

Management of AC Joint Arthritis with Greater Tuberosity Irregularity

For this patient with 2 months of shoulder pain, moderate AC joint arthritis, and a tiny bony irregularity of the greater tuberosity, begin with conservative management including NSAIDs, activity modification, and physical therapy, as the imaging findings represent degenerative changes rather than acute trauma requiring surgical intervention. 1

Interpretation of Imaging Findings

The radiographic findings reveal two distinct pathologies that require different management approaches:

AC Joint Arthritis

• Moderate narrowing and arthritic changes at the AC joint represent degenerative osteoarthritis, which commonly causes anterior or superior shoulder pain, particularly with overhead and cross-body activities 1
• This condition typically occurs in middle-aged individuals due to degeneration of the fibrocartilaginous disk 1
• Critical caveat: Radiographic evidence of AC joint degeneration alone cannot establish the diagnosis, as similar findings appear in asymptomatic individuals 1

Greater Tuberosity Irregularity

• The "tiny bony irregularity" over the greater tuberosity likely represents chronic degenerative changes rather than an acute fracture, given the 2-month duration and absence of trauma history 2
• If this were an acute displaced fracture, the traditional teaching suggests surgical fixation for displacement >5 mm in general population or >3 mm in overhead athletes 2
• However, recent evidence challenges the "5 mm rule" - a 2023 study demonstrated that greater tuberosity fractures with >5 mm displacement treated nonoperatively achieved excellent outcomes with no difference in range of motion or pain compared to minimally displaced fractures 3

Conservative Management Algorithm

First-Line Treatment (0-6 weeks)

• Start with acetaminophen, then escalate to NSAIDs if inadequate response 4
• Activity modification: Avoid overhead and cross-body movements that provoke AC joint pain 1
• Physical therapy: Exercise has been shown to reduce pain and disability in osteoarthritis 4

Second-Line Treatment (6-12 weeks if persistent symptoms)

• Diagnostic AC joint injection with local anesthetic to confirm the AC joint as the pain source, as physical examination findings lack specificity 1
• If the injection provides temporary relief, proceed with corticosteroid injection into the AC joint for short-term relief (4-8 weeks) 4

Surgical Consideration (if conservative management fails after 3-6 months)

• AC joint resection arthroplasty (open or arthroscopic) provides predictable pain relief for refractory symptomatic AC osteoarthritis 1

Additional Imaging Considerations

MRI without contrast is NOT immediately necessary based on current findings, but should be obtained if: 5

• Symptoms persist despite appropriate conservative management
• Clinical suspicion for rotator cuff pathology develops (the greater tuberosity carries rotator cuff insertions) 2
• Need to evaluate for associated partial-thickness rotator cuff tears or labral tears, which can occur with greater tuberosity fractures 2

Ultrasound is an equally appropriate alternative to MRI for evaluating rotator cuff integrity if concerns develop 5

Critical Pitfalls to Avoid

• Do not assume the AC joint is the pain source based solely on radiographic arthritis - asymptomatic AC degeneration is common; diagnostic injection is essential for confirmation 1
• Do not rush to surgery for the greater tuberosity irregularity - given the chronic timeframe (2 months) and "tiny" size, this likely represents chronic changes rather than acute displaced fracture requiring fixation 2, 3
• Ensure adequate radiographic views were obtained - the report mentions standard views, but if clinical suspicion for occult pathology persists, consider additional imaging 6, 5
• Monitor for rotator cuff symptoms - greater tuberosity pathology may be associated with rotator cuff tears that could cause persistent pain after bone healing 2