AVN

Complications

Types

Chondrolysis

AVN

Definition

Spontaneous osteonecrosis of the navicular

Indications for THA

Osteoarthritis

- abnormal morphology

- loss of head neck offset

- bony impingement on acetabulum

AVN

Definition

Osteonecrosis of the navicular

Epidemiology

Present at age 4-6 years

- same as Perthes disease

M:F 5:1

Bilateral in 20%

Aetiology

Repetitive trauma to maturing ossific nucleus

Indications

< 60 with good bone stock and preserved joint space

Reduction

Union rates increased with anatomical reduction

Options

- closed reduction

- open reduction / if closed reduction fails

Accept

- no varus

- < 15^o valgus

- < 10^o AP plane

Non-Operative

Education regarding shoe wear

- extra wide / large toe box

Insoles

- longitudinal arch support

- pre MT dome for metatarsalgia

- podiatry to attend to callosities

Toe spacers

Analgesia

Operative

Indications

1.  Continued pain and discomfort

2.  Difficulties with shoe wear

Incidence

Young men

Posterior / Anterior 9:1

Aetiology

High velocity injury

- head direction at impact decides direction of dislocation

Anterior Dislocation 

Externally rotated & abducted leg

- flexion = inferior dislocation

Two groups of dislocated hips

1.  Late presenters

2.  Failures of splint in those < age 6/12

Options

1.  Adductor tenotomy + closed reduction

- most surgeons will attempt this initially

- risk of AVN wilth forceful reduction / excessive abduction

2.  Open Reduction

- for failure of closed reduction

Aim

To obtain and maintain a concentric reduction without complication

Timing

0 - 6 /12

- best time for treatment

- maintain reduction of head & allow normal acetabular development

Equivocal Hip

Obtain ultrasound

Graaf 2A and 2B

- Alpha angle 50 - 59^o range

- many will resolve without treatment

Management Summary

Stage 0

Natural history mixed

- depends on size of lesion and diagnosis

- treat if becomes asymptomatic

- may benefit from bisphosphonates

Stage 1 / Normal X-ray, abnormal MRI

Forage: 80% G/E

Bisphosphonates

Stage 2 / Abnormal X-ray with cysts and sclerosis

A:  As for Stage I