incidence

Epidemiology

Much less common than hip and knee OA
Patients tend to be younger

Incidence

Indications for THA

Osteoarthritis

- abnormal morphology

- loss of head neck offset

- bony impingement on acetabulum

AVN

Incidence

1 - 2 %

Anatomy

Medial Aspect of foot

- proximal to navicular

- part of T posterior tendon

Usually will fuse with navicular (50%)

Issues

1.  Probably not a cause of flat foot

- excising accessory navicular / rerouting / reattaching tibialis posterior

- will not help pes planus

2.  Pain

- may fracture

Definition

Tibial facture with break in skin

- open wound communicating with fracture or haematoma

Patient is immediately at higher risk of deep infection

Diagnosis

Wound continuously oozes dark red fracture haematoma

Epidemiology

Up to 1/4 of tibia fractures open

Gustilo and Anderson Classification

Grade 1

- wound < 1cm

- usually inside out

Incidence

10%

Requirements

70^o  swing phase

80^o climb up stairs

90^o climb down stairs + sit down in chair

100^o low chair

NHx

Stiffness usually subsides at 6-8/52

- generally improves out to 3/12

- slow improvement for up to next 9/12

Arterial injury

Incidence

0.05%

Types

1. Thrombosis

- most common scenario

- tourniquet with atherosclerosis

- indirect damage to vessel

- femoral or popliteal

2.  Embolisation

- atherosclerosis again

- blue toes syndrome post operatively

3.  Vessel transection

Incidence

Knee > Hip

- superficial position

- limited cover of well vascularised muscle 

- watershed area of skin blood supply anterior to the skin incision 

- much increased in fully constrained prosthesis 

Ideal < 1%

Risk Factors

Increased with

- revision

- prior infection

- RA / Psoriatic arthropathy

- DM

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