total hip arthroplasty

Tsukayama Classification

Indications

Patient > 70

Gjertsen et al JBJS Am 2010

- 4335 patients > 70 with displaced subcapital fractures

- minimum 1 year follow up

- 1 year mortality same in each group / 25%

- 22% reoperation in ORIF v 3% in hemiarthroplasty

- more pain / higher dissatisfaction / lower quality life in ORIF group

Options

Hemiarthroplasty

- unipolar monoblock

- unipolar modular

Definition

Chronic, non metabolic bone disorder

Characterised by increased bone resorption, bone formation and remodelling

Epidemiology

Rare < 40

1 – 3 % population over 60

M > F

Aetiology

Unknown

Paramyxovirus implicated

- measles

- RSV

- canine distemper virus

Electron Microscope

Goal

Initial press fit

- implant geometry fits the cortical bone in the proximal femur

- good initial mechanical stability

Biological fixation for success

- good press fit

- minimal micromotion

- bony or fibrous tissue ingrowth or ongrowth

Aim

Reproduce the normal anatomical centre of rotation

Restore femoral offset 

Maintain equal leg lengths 

Usually template off normal hip

Template

1. LLD

2. Offset

3. Femoral component

4. Acetabular component

5. Osteotomy / femoral seating

Types

Peri-operative

- incurred during operation

Post operative

- related to osteolysis / trauma / infection

Follow up

1994 National Institutes of Health Consensus on THR

Aetiology

Intrinsic

Infection

Loosening

Thigh pain in uncemented

- micro motion at distal end of stem

- modulus mismatch

Stress fracture / insufficiency fracture

- pubic rami, sacral

Intra-operative fracture

Prosthesis failure

Subtle instability

Extrinsic