indications

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

Indications 

1. Significant functional impairment

2. PIPJ contracture

- originally thought to intervene early

- Macfarlane showed residual FFD always about 30^o

- may need to release  check rein ligaments / accessory collateral ligaments

3. MCPJ contracture >30^o

4. Trigger fingers

- must do limited fasciectomy 

History

First generation (late 70s early 80s) 

Results

Advantage

1.  Reduce implant loosening

- offset load sharing to diaphysis

- 30% if > 70 mm

2. Restore optimal alignment

Indications

1.  Using augments or bone grafting

2.  Increased constraint 

- VVS / hinge

Indications

Aseptic loosening

Infection

Instability

Wear & breakage components

Fracture

Stiffness 

Pain

Aims

Restoration of anatomical alignment

Restoration of joint line

Restoration of bone stock

Aim

Attempt to reduce outliers in all 3 planes of the knee

- improve alignment

- theoretically improve survival and outcomes

Types

Image based

Pre-op CT

- uncommon

- resource heavy

Philosophy

Need the least amount of constraint necessary to obtain sufficient stability

Increasing constraint

Advantages

- increase stability

Disadvantage

- increase stress at implant host interface

3 Types

1.  Unconstrained

A.  Posterior cruciate retaining

Options

1. Always resurface

2. Never resurface

3. Selectively resurface

Decision Making

Controversial

- literature divided on issue

Historically

- poor outcomes due to poor implant design

- now improved designs

- non resurfacing also improved due to better design and improved techniques in regard to tracking and rotation

Aim

UKA is intended to be load sharing

- correct to neutral or slight varus

HTO is a load-shifting / load-sparing procedure

- over correct into valgus

UKA v TKR

Advantages UKA

1.  Rapid rehabilation

Aetiology

Trauma

RA

Rickets / osteomalacia

Issues

Horizontal joint line important

- < 10° tilt acceptable

> 10^o joint line tilt / due to femoral valgus

- continues to overload lateral compartment