Ch 49 - Scapula fractures

Question 1

What percentage of scapular fractures have concurrent injuries?

Answer 1

56 - 70%

Question 2

What is the anatomical classification system of scapular fractures?

Answer 2

• Type I: Fractures of the body and spine
• Type II: Fractures of the neck
• Type III: Glenoid fractures

Question 3

What is the fracture classification scheme as described by Cook et al?

Answer 3

From least to most severe:
- Stable, extra-articular
- Unstable, extra-articular
- Intra-articular

Question 4

What muscles are encountered during the lateral approach to the shoulder?

Answer 4

• Omotransversarius and trapezium
• Deltoideus
• Supraspinatus and infraspinatus

Question 5

What are the surgical options of fixation of scabular body fractures?

Answer 5

• Plate fixation (Thicker bone cranial to spine distally and caudal to spine proximally)
• Interfragmentary cerclage
• Partial or total scapulectomy - can remove 60% and retain excellent function

Double plating was stronger but not stiffer and both failed by bending at much greater than clinically expected loads

No significant benefit has been shown with locking plate however study had multiple flaws i.e intact scapulas

Question 6

What are the fixation options for fracture of the acromion?

Answer 6

• 2 K-wires and figure of 8 tension band
• Interfragmentary wires
• Single interfragmentary wire

Question 7

What are the fixation options of scapular neck fractures?

Answer 7

• Approach laterally or craniolaterally
• Osteotomy of acromion usually required (or tenotomy of deltoid, or muscle seperation approach)
• Osteotomy of greater tubercle of humerus sometimes required
• Cross-pins
• Divergent pins
• Plate (T- ot L-shaped)

Question 8

What percentage of scapular fractures are articular?

Answer 8

28%, most commonly cranial glenoid

Question 9

When does the accessory ossification of the supraglenoid tuberosity fuse?

Answer 9

By 5mo

Question 10

How do you approach a supraglenoid tuberosity fracture?
What are the repair options?

Answer 10

Approach
- Cranial approach with osteotomy of greater tubercle
- OR - Longitudinal myotomy of supraspinatus muscle from midbelly to humeral insertion

Fixation
- Interfragmentary lag screw and antirotation wire
- 2 K-wires and tension band
- Excision and tenodesis

Question 11

What are the surgical options for a T/Y-fracture of the glenoid?

Answer 11

• Craniocaudal lag screw for anatomical reconstruction of articular surface anf then correct neck fracture as previously describes
• Fractures of medial/lateral labrum can be fixed with lateromedial lag screws if sufficient bone stock
• Excision of the glenoid (excisional arthroplasty)
• Partial scapulectomy
• Arthrodesis

Question 12

How do you treat scapular avulsion?

Answer 12

Caused by rupture of serratus ventralis

Fixation:
- 20-22g cerclage wire around 5th/6th/7th rib and through holes in caudodorsal border of scapula
- +/- reattachment of serratus ventralis through drill holes at craniodorsal scapula
- Velpeau sling 2-3wk
- Prognosis excellent

Question 13

What is this condition?
Is it clinically significant?

Answer 13

• Ununited accessory ossification center of the caudal glenoid
• Can cause lameness if unstable
• Requires arthroscopy to determine stabiliy and can be removed if unstable