What is the treatment for os acromiale?

Treatment of Os Acromiale

For symptomatic os acromiale that fails conservative management, open reduction and internal fixation (ORIF) using cannulated screws with or without tension band wiring is the preferred surgical approach for meso-type fragments, while excision is reserved for small pre-type fragments. 1, 2, 3

Initial Conservative Management

• Conservative treatment is first-line therapy for all symptomatic os acromiale, typically lasting 3-6 months before considering surgical intervention 4, 1
• Conservative measures include NSAIDs, physical therapy focusing on rotator cuff strengthening, and activity modification 1
• Diagnostic injection into the os acromiale junction can confirm the diagnosis and predict surgical success—positive pain relief with local injection strongly supports os acromiale as the pain source 5

Surgical Indications

Surgery is indicated when:

• Conservative treatment fails after adequate trial (typically 3-6 months) 5, 1
• Highly painful and unstable os acromiale is present 1
• Associated rotator cuff tears require repair 1, 3

Surgical Technique Selection by Fragment Type

For Pre-Type (Small) Os Acromiale:

• Excision is the preferred approach for small anterior fragments 1, 3
• Can be performed open or arthroscopically 1

For Meso-Type (Large) Os Acromiale:

• Open reduction and internal fixation is preferred to preserve deltoid attachment and function 1, 2, 3
• Cannulated screw fixation alone or combined with tension band wiring demonstrates superior union rates and outcomes 2, 3
• The combination of both techniques may provide biomechanical advantages 2
• Bone grafting from the local site is adequate—iliac crest grafting offers no additional benefit despite historical use 5, 2
• Preservation of anterior deltoid attachment is critical to avoid persistent dysfunction 3

Specific Technical Considerations

• Tension band wiring minimizes upward migration of the fragment and promotes union 5
• Avoid simple acromioplasty in the presence of os acromiale, as this can worsen symptoms and destabilize the fragment 5
• When rotator cuff tears coexist, they can be addressed arthroscopically or through open transacromial approach, followed by ORIF of the os acromiale 3

Expected Outcomes

• ORIF achieves reliable union in properly selected patients, with studies showing 100% union rates on CT scan 5
• Pain relief occurs in approximately 70% of patients following ORIF 5
• Functional scores improve significantly—mean Constant scores improve from 53.4 preoperatively to 82.2 postoperatively 5

Critical Pitfalls to Avoid

• Do not perform isolated acromioplasty when os acromiale is present—this was attempted in some patients with subsequent failure to relieve pain 5
• Do not excise large meso-type fragments, as this risks persistent deltoid dysfunction 3
• Always evaluate for os acromiale before performing subacromial decompression, as unrecognized os acromiale can lead to surgical failure 5, 4

Diagnostic Confirmation

• Standard shoulder radiographs including axillary views are initial imaging 4
• CT scan or MRI confirms the diagnosis and evaluates fragment stability and associated pathology 4, 1
• Diagnostic injection provides functional confirmation that the os acromiale is the pain generator 5, 1