What isa DFO?

DFO is a surgical procedure to realign the lower thighbone, relieving arthritis on one side of the knee and transferring pressure to the healthy side. Common for "knock-kneed" patients with isolated arthritis.

Often chosen by younger individuals with unicompartmental osteoarthritis instead of knee replacement.

knock kneed

This patient is naturally “knock kneed” however, due to cartilage damage on the outer side of the knee, his left knee is more “knock kneed” than his right.
He is 23 years of age and not suitable for any knee replacement surgery.

What investigations will I need prior to surgery?

You will require a MRI scan of your knee to ensure the other parts of your knee are also not damaged with arthritis.

Cartilage LossMRI scan showing areas of severe cartilage loss (red arrow) on the outer side of the knee. (green arrows indicate areas normal cartilage)
Cartilage NormalMRI scan showing cartilage on the inner side of the knee is normal (circled).

You will require a special long x-ray from taken from your pelvis to your ankles whilst you are standing. This x-ray helps calculate where most of the load is distributed in your knee, the severity of the deformity affecting the knee as well as the degree of correction required to unload the diseased part of the knee.

Pre surgery long x-ray. The axis (green line) of the left leg is through the outside of the knee. The right leg has had a previous femoral osteotomy.

Pre surgery long x-ray

Post-surgery long x-ray showing correction of the left leg axis (green line) through the inner side of the left knee.

Post-surgery long x-ray

What happens during DFO Surgery?

  • 1
    A DFO is a major surgical procedure performed under general anaesthetic with the use of Computer Navigation for increased accuracy.
  • 2
    The surgery begins with an arthroscopy to inspect the inside of the knee using a telescope.
  • 3
    Computer Navigation requires attaching special sensors to the thighbone and shinbone via pins, which are removed after surgery.
  • 4
    Before performing the osteotomy, the computer calculates the leg alignment using the bone sensors.
  • 5
    The lower part of the thighbone (femur) is dissected out, and temporary wires are inserted into the bone along the proposed osteotomy line.
  • 6
    Using a saw, the osteotomy is performed, and its correction is calculated in real-time until the predetermined correction angle is achieved.
  • 7
    A special plate and screws are used to hold the osteotomy in position.
  • 8
    Bone blocks from the top of the pelvis are packed into the osteotomy site to promote accelerated healing.
The computer calculates the pre-osteotomy deformity.
The osteotomy is performed and the deformity is corrected until the predetermined angle is achieved.

Will I need to wear a brace?

You'll need a brace for 12 weeks after surgery. Initially, it allows full knee straightening and 30-degree bend for 2 weeks. From weeks 2 to 8, the brace will unlock gradually for increased bending.

Can I put weight on my leg?

First 6 weeks: Touch weight bearing for balance only.
Next 6 weeks: Gradually increase weight on leg.
12-week mark: Full weight bearing post-surgery.

How long does the surgery take?

On average the surgery takes 2 hours.

How long does it take to make a full recovery?

The bone will take 12 weeks to heal but the full recovery will take 9-12 months due to the rehabilitation required.

What complications can occur from the surgery?

Complications are uncommon but can include

  • 1
    Loss of position of the osteotomy
  • 2
    Blood clots to the leg (DVT) or lungs (PE)
  • 3
    Persistent Bleeding
  • 4
    Knee stiffness
  • 5
    An unwanted fracture of the bone during or after the surgery
  • 6
    The osteotomy not healing
  • 7
    Loss of position of the osteotomy
  • 8
    Persistent pain after the surgery
  • 9
    Numbness around the scar as well as lower leg
  • 10
    Damage to the artery at the back of the leg
  • 11
    Compartment Syndrome
Knee background

Do you need a

Knee replacement?

Dr Seeto in affiliation with Medibank Private and East Sydney Private hospital, offers a program for eligible Medibank Private Members, to eliminate medical out of pocket costs for your Knee Replacement.

The program includes a pre-surgery preparation program, spending the minimal time necessary in hospital, as well as home rehabilitation if necessary.


Out Of Pocket

Knee operation

Book a consultation


Contact us