1) Os acromiale occurs when the acromion fails to fully fuse during development, leaving separate ossification centers. It has a reported incidence of 1.4-30% and is often asymptomatic. 2) Treatment options for symptomatic os acromiale include non-operative measures like physiotherapy, injections, or surgical excision or fixation of the fragments. Arthroscopic excision aims to preserve deltoid attachment with good reported outcomes. 3) Acromial fractures can occur from direct trauma or overuse. Indications for surgical fixation include symptomatic nonunion, impingement, or displacement over 1cm. Posterior plating techniques are commonly used.

1. Os acromiale, Acromial # and
acromial insufficiency
James Wilson
ST8 Trainee T&O
Upper Limb Fellow
Wrightington Hospital

2. • Scapula ossified from 9 or
more centres
• Body - 8 weeks
• Middle Coracoid 15-18
months
• Base coracoid
• Base acromion
• Inferior angle
• Tip of acromion
• Vertebral border
Embryology

3. • 1 Flat
• 2 Curved
• 3 Hooked
• 4 Convex
Morphology

4. • PA = Pre-acromion
• MSA = Meso-acromion
• MTA = Meta-acromion
• Meso and Meta-acromion
junction most common
• Nomenclature
Os Acromiale

5. • Incidence 1.4-30%
• 33-62% bilateral
• Types -
• 1: between meso and meta acromion
(typical)
• 2: between pre and meso acromion
• 3: between pre and meso as well as
meta acromion
• 4: between all three ossification
centres
Os Acromiale

6. • Presentation
• Signs and symptoms of
impingement
• Night Pain
• Tenderness
• Indirect - Cuff tear
• Diagnosis
• Best seen on axillary
view
Os Acromiale

7. • Nothing (if asymptomatic)
• Non operative
• Physiotherapy
• Injections
• Subacromial space
• intra-lesional
• Surgical
• Excision
• Acromioplasty
• Fixation
Treatment

8. • Arthroscopic v’s Open excision
• Theoretically arthroscopic preserves the deltoid attachment
• No comparative studies
• Pagnani - Arthroscopic excision 11 Mesoacromiales (18-25yrs)—
return to sport and full strength by 14 weeks
• Wright - Arthroscopic excision 13 Mesoacromiales (Mean age 36)
- full strength 26 weeks 85% satisfaction (11/13)
• Boehm et al and Warner et al performed open excision with
deltoid reattachment. (4 pre and 5 meso)
• Boehm - similar outcomes to acomioplasty and fixation.
• Warner - good outcomes with pre-os excision, poor
outcomes for meso-os excisions
Excision

9. • Abbound - mixture of open (5) and arthroscopic (6) acromioplasty
of patients with a stable mess-os. Retrospective comparison with
mixture of K-wire (5) and cannulated screw fixations (3) - no
significant difference.
• Boehm - Open acromioplasty retrospectively compared with k-
wire fixation - equivalent satisfaction and Constant scores
Acromioplasty

10. • Review found
• Cannulated screw fixation 96% (23/24)
• K-wire 63% (31/49)
• Union correlated with outcome and satisfaction scores
• Removal of metalware
• Cann screw 38%
• K-wire 88%
• Complications
• Deep infection - Open excision (1), Open acromioplasty (2),
ORIF (1) all had I&D
• Superficial infection - ORIF (2) settled with ABx
Fixation

11. • Rare
• Mechanism
• Direct blow
• Avulsion due to deltoid
• Overuse
• Complication of reverse TSR
• Indications for fixation
• Symptomatic non-union
• Subacromial Impingement
• >1cm displacement
• Open injuries
• Multiple disruptions of the SSSC
Acromion fractures

12. • Posterior approach
• Lateral decubitous position
• Incision over posterior border
of acromion and along spine
Fixation Technique

13. • Deltoid elevated off with
infraspinatus to expose
fracture
• Laminar spreader used to
distract fragments to
facilitate cleaning and
reduction
Fixation technique

14. Fixation Technique

15. • Smaller lateral fractures can be fixed with a
similar technique
• 2.7 screw with 2mm mini-fragment plate
Fixation Technique

16. • 457 RSA
• 5 centres
• 40 shoulders identified with
acromial pathology
• Os Acromiale (23)
• Aquired acromial lesions
(17)
• Non union scapula spine (1)
• Post operative scapula
spine fracture (4)
• No acromial pathology
(416)
Insufficiency