ultrasound

Non Union

Definition

 

Non-union

- arrest of progression to union at fracture site 

- > 6-9 /12

- no visible progressive signs of healing for at least three consecutive months

- individualise for each fracture

- when the surgeon believes the fracture has little or no chance to heal

 

Delayed union

- failure of fracture to unite within expected time

- still may spontaneously unite

 

Ultrasound

Physics

 

Very high frequency sound waves

- 3 - 15 MHz

 

Production

 

Piezoelectric effect

- run electric current through a crystal

- produces ultrasound waves

 

Theory

 

Density of substance determines velocity of the US

- reflected back to the probe at different velocities

- converted into 2D image on monitor

 

 

Basic Science

Pathogenesis

 

Virchow's Triad

1. Venous stasis

2. Hypercoagulability

3. Endothelial damage

 

Starts as platelet nidus at valves

- thrombogenic materials elaborated by platelets

- leads to development of fibrin thrombus

- thrombus grows

 

Thrombus may 

- detach as embolus

- be completely dissolved / recanalise

- organise with valve incompetence

Infected THR

Risk factors

 

Patient 

 

Advanced age

Immunosuppression - steroids / Rheumatoid / DM

Malnutrition - Lymphocyte count / Transferrin / Albumin

Vascular disease

Obesity

Poor skin i.e. psoriasis

Previous infection in joint

Infection elsewhere - i.e. UTi

Prolonged hospital admission

Revision surgery

 

Operative Factors

 

Preoperative

Achilles Tendon Rupture

AnatomyAchilles tendon anatomy

 

Gastrocnemius tendon 10-25 cm long

- soleus 3-10 cm

- inserts superior calcaneal tuberosity

- fibres spiral 90°

- fibres that lie medially in proximal portion become posterior distally

- allows elastic recoil & energy storage

 

Plantaris present in 90% population

- medial to T Achilles

 

Poor blood supply midportion

- mesotenal vessels