nonunion

Epidemiology

Elderly population

Less common in younger population

Lateral 1/3 Neer Classification

Type I

Fracture lateral to the CC ligaments

- does not extend into the ACJ

- non displaced

- most common 4:1

Mechanism

Usually a direct blow 

- less commonly a fall on the outstretched hand

RTA / sporting accidents commonest causes

Can be pathological as a result of radionecrosis

- eg following radiotherapy for breast cancer.  

Incidence

Fractures of the clavicle are common

Definition 

Failure of fusion of adjacent ossification centers

Epidemiology

Incidence 3%

Bilateral in 60%

Anatomy

4 ossification centers present in acromion

- pre-acromion

- mesoacromion

- metaacromion

- basiacromion

Epidemiology

Average age 6 years

20% distal humeral fracture

- second most common elbow fracture after supracondylar

Mechanism

Pull Off 

- more common 

- fracture begins posterolateral metaphysis

- LCL, ECRL & ECRB attached to fragment

Push off

- varus force to extended EJ

Classification

Meyers & McKeever classification

Type I:   Undisplaced avulsion fracture

Type II:  Anterior portion displaced & hinged

Type IIIA:   Displaced

Type IIIB:   Displaced & Rotated

Types

1.  Dorsal lip fracture / Tuberosity fracture

- avulsion fractures

- most common

- beware avulsion T post

2.  Body fracture

3.  Stress Fractures

Body Fractures

Types

A.  Transverse fracture in coronal plane

B.  Transverse from dorsolateral to plantarmedial

C.  Central or lateral comminution