revision

Timing

Early < 3 - 6 months

- most common

Stryker dual mobility

Concept

AORI / Andersen Orthopedic Research Institute

T Tibial  F Femoral

1.  Contained Metaphyseal Defect

2.  Damaged Metaphyseal

A.  One Condyle

B.  Both Condyles

3.  Deficient Metaphysis +/- collaterals +/- extensor mechanism

1.  Contained Metaphyseal defect 

Intraoperative Fractures

1.  Shaft fracture from IM rod

2.  Posterior condylar fracture

Management

- assess stability

- ORIF if needed

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

Incidence

Up to 8% patients with ACL reconstruction will have recurrent instability and graft failure

- increased with surgical inexperience

Graft can

1.  Be inadequate from the start

- inadequate tension

- poor tunnel placement

Advantage

Fewer complications than TSR

Simpler procedure

Causes for failure

1.  Patient factors

A.  Recurrent Trauma

- contact athletes higher risk

B.  MDI / Ligamentous Laxity / Voluntary dislocaters

C.  Poor rehabilitation

- poor motivation

- too rapid

- patients rarely get stiff, better to go very slow

2.  Surgeon Factors

A.  Unrecognised bony defect

Incidence

Variable

- may be up to 50% retear over time

- many asymptomatic

MRI

Options