investigations

Epidemiology

1/3 caucasian women > 64

Risk Factors

Insufficient bone mass at time of skeletal maturity

- peak bone mass is achieved at age 25

Rapid loss of bone after menopause

Low body weight / weight loss / history of smoking / steroids

Primary

Type 1

- postmenopausal

- high turnover / osteoclast mediated

- F x 6

AP / Long Leg Views

Quantify Valgus Malalignment

Lateral Xray

1.  Assess Patella Alta

30^o flexion

Issues

Rule out infection

Assess rotator cuff / bone stock preoperatively

Approach

- difficult / scarring +++

- very difficult to restore any loss of ROM

Removal of prosthesis

Glenoid

- may not be able to revise

Humeral component

- long stem

Investigations

Rule out infection

- CRP / ESR

- ultrasound or xray guided aspiration

Anatomy

Developmental Anatomy

Knee joint first appears as a mesenchymal cleft at 8 weeks gestation

- ACL and PCL separate entities by week 10

Definition

Clostridial Myonecrosis

- necrotizing, gas producing infection of skeletal muscle 2° Clostridia

- life threatening & rapidly progressive

Classification

There are 3 types of bacterial gas-forming infections

1. Classical clostridial gas gangrene

- rapid onset of sepsis / couple of days

- muscle nearly always involved

- critically ill immediately following an open injury