TKA
Instability
Types of Instability
1. AP Instability
2. Varus Valgus Instability
3. Global Instability
4. Frank Dislocation
Lower Limb Alignment
Definition
Deformity causing alteration of mechanical axis from knee centre
Aims
1. Normal leg alignment
2. Equal leg lengths
Surgical Technique Varus Knee
Goal
Pain relief combined with a balanced range of motion, strength & stability
Indications
Painful arthritic knee
- OA
- RA
Functional limitation
Ideal Patient
- > 65
- thin
Australian Joint Registry 2010
Numbers
9 years up to 31 December 2009
- 289 000 TKR
- 80% primary
- 11% primary partial
- 8.5% revision
TKR Revision Rate
9 year revision rate of 5.1% OA
- 4.5% in RA
Causes
- loosening 30%
- infection 20%
Alignment
Principle
Correct alignment and soft tissue balancing
- two of the most important aspects of successful TKR
Technical Goals
1. Restoration of mechanical alignment
- forces of the leg pass through the centre of the hip, knee and ankle