acromion - os-acromiale fractures and insufficiency
TRANSCRIPT
Os acromiale, Acromial # and acromial insufficiency
James Wilson
ST8 Trainee T&OUpper Limb Fellow
Wrightington Hospital
• 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
• 1 Flat
• 2 Curved
• 3 Hooked
• 4 Convex
Morphology
• PA = Pre-acromion
• MSA = Meso-acromion
• MTA = Meta-acromion
• Meso and Meta-acromion junction most common
• Nomenclature
Os Acromiale
• 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
• Presentation
• Signs and symptoms of impingement
• Night Pain
• Tenderness
• Indirect - Cuff tear
• Diagnosis
• Best seen on axillary view
Os Acromiale
• Nothing (if asymptomatic)
• Non operative
• Physiotherapy
• Injections
• Subacromial space
• intra-lesional
• Surgical • Excision
• Acromioplasty
• Fixation
Treatment
• 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
• 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
• 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
• 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
• Posterior approach
• Lateral decubitous position
• Incision over posterior border of acromion and along spine
Fixation Technique
• Deltoid elevated off with infraspinatus to expose fracture
• Laminar spreader used to distract fragments to facilitate cleaning and reduction
Fixation technique
Fixation Technique
• Smaller lateral fractures can be fixed with a similar technique
• 2.7 screw with 2mm mini-fragment plate
Fixation Technique
• 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