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Distal Femoral Osteotomy

Pre-Operation

Patients will complain of either an acute or chronic onset of pain at the outside of their knee. The pain is made worse with weight bearing activities.

As part of the patient assessment, x-rays referred to as  “long-leg-standing views” are required. Using these images Dr. Porter can determine the mechanical axis, that is where the weight is transferred through the knee. If this is through the damaged lateral side of the knee, correction of the mal-alignment may be required to relieve the patient’s discomfort and / or slow the progress of the degeneration within the knee. This is achieved by changing the shape of the femur or thigh bone.

Dr. Porter will plan the operation based on the x-rays, in order to ensure that the “osteotomy” off-loads the lateral compartment of the knee.

This operation may be performed in young patients, or middle-aged patients. In the middle aged patients it is often performed to delay the need for a knee replacement, often by 5-15 years.

The shape of the femur can be altered to create a more virus knee, by either taking a wedge of bone from the inside (medial closing wedge) as seen above right) or by opening up space and inserting a wedge of bone on the outside (lateral opening wedge). Both operations can correct the mal-alignment but have different minor effects on the overall leg length.

Operation

The operation is performed in a sterile operating theatre, with the patient under a general anesthetic.

The operation is performed as an open procedure with the incision on either the inside or outside of the distal thigh and knee, depending upon the specific surgery being performed .

The thigh bone (femur) is exposed and then either a wedge of bone resected, or a wedge of bone inserted. X-rays are taken throughout the procedure to ensure that the mechanical axis is corrected appropriately. Following this the bone cut is stabilised with a metal plate and screws, that holds the bones in place until the bone has healed.

The knee is placed in a range of motion brace until the bone has healed, and this is at least 2 months.

Patients will spend at least one night in hospital and will be on antibiotics for at last 6 days, and a blood thinner. Patients are only allowed to partial weight bear for 2 months.

 

Potential
complications

Despite our best attempts, potential complications are a risk with any injury or surgical procedure. You need to be aware of these rare potential complications.

The more common ones are listed here, but please ask the surgeon if there are any you are particularly concerned about.

1. Infection

There is a 1% risk of superficial wound infection, which may respond to oral antibiotics. There is a lower risk of deep infection but this usually requires a return to theatre to wash the wound out as well as intravenous antibiotics.

2. Delayed union or non-union

Sometimes the osteotomy can take longer than 2 months to heal, and on rare occasions it does not heal. The latter may require a return to the operating theatre to either add further bone graft and / or redo the operation.

3. Thrombosis or DVT

The surgery and period in the brace increases the risk of developing and thrombosis or DVT. For this reason the patient is placed on a blood thinner for at least 10 days to reduce the risk of this occurring.

4. Nerve or vessel injury

Because the surgery involves cutting through the femur, there is a risk fo damage to the nerves and vessels lying behind the bone. This is a serious potential complication and Dr. Porter ensures that these structures are protected before he cuts through the bone.

5. Recurrent pain and need for a knee replacement

Although most patients experience significant relief of their pain, the duration of relief is hard to predict. The patient still has to protect the knee and exercise the measures shown to slow the progress of the wear and tear in the knee. In some patients the pain does come back earlier than expected and the only solution may be conversion to a knee replacement.

Post-Operation

Immediately post surgery

  • You will wake up in the recovery ward with your leg held immobile in a
    brace
  •  The wound will be closed with stitches, covered with dressings, and a
    heavy bandage
  • A nurse will monitor you and administer pain killers to keep you
    comfortable
  • You will be discharged from the recovery ward to an orthopaedic ward,
    when you have recovered sufficiently from the procedure
  • Your surgeon will either see you in recovery, or later on that day, in the
    ward. At that time your surgeon will explain to you the findings at surgery
    and the precise procedure performed.
  • You will be prescribed pain-killers, antibiotics, and a blood-thinner, for
    the duration of your stay in hospital. If you require more pain-killers than
    you are receiving regularly, you can ask a nurse for more, to keep you
    comfortable
  • Before discharge, the follow up arrangements will be explained to you.
    You will also be given pain killers and/or a script to control your pain a
    home, as well as any other medication that may be required, including the
    blood thinner to reduce the risk of forming leg clots

Discharge to post-op review

  • You will be able touch weight-bear through the operated leg until 2
    weeks post-surgery or until your first post-operative review
  • Keep the limb elevated when not mobilizing on crutches, and keep the
    latter to a minimum for the first 2 weeks. This will help to reduce swelling
    and control pain.
  • You will be encouraged to do some early range of motion exercises for the
    knee, foot and ankle, in addition to early quadriceps setting and co-
    contractions (this will be explained to you by the surgeon and / or
    physiotherapist).
  • Take the medications as prescribed by your anesthetist to control pain
  • You will start physiotherapy within a week of surgery, and the
    physiotherapist will supervise your rehabilitation along the guidelines
    detailed in the attached table
  • Phone the surgeon’s rooms to make an appointment 10-14 days post
    surgery. You may receive a text message, e-mail or phone call to confirm
    this. Contact your surgeon earlier if there are problems.

First post-op review

  • You will be reviewed by your surgeon 10-14 days post surgery. He will
    assess the healing of the incisions and remove or trim the sutures
  • He will liaise with your physiotherapist if any alterations in the standard
    rehabilitation regimen are indicated
  • You will be allowed to commence touch weight bearing with the brace
    locked in full extension, from 2 weeks post surgery. The amount of weight
    bearing and range of motion will be increased as per the attached table. A
    second review will be schedule for 8 weeks post surgery. An x-ray of the
    knee will be performed as close to the second review as possible.
  • You will continue with physiotherapy and you will be allowed to
    commence partial weight bearing up to 20kg.

Second post-operative review (8 weeks)

  • The surgeon will review you and the x-rays to check healing of the
    osteotomy site, around 8 weeks post surgery.
  • If all is well you will be allowed bear full weight on the operated side,
    initially while wearing the brace.

Third post-operative review

  • This will be 3-4 months post surgery
  • Again a check x-ray will be performed a few days prior to this
    appointment. In most cases your bone healing will be well advanced at
    this stage. If so you may be allowed to slowly introduce full weight
    bearing

Fourth post-operative review

  • Your surgeon will see you again at 6-12 months post surgery with a
    check x-ray.
  • At this review your osteotomy site should be solidly healed and you
    should be able to walk, cycle and swim.
  • Following this review you may be allowed to introduce some low
    impact activities, such as doubles tennis.

 

Rehab / Physio

Rehab Program

0 – 4 weeks

Weight bearing – The brace is locked for all weight bearing, and up to 20Kg weight bearing is allowed

Brace – Locked in full extension all the time, removed for exercises only

ROM – Non weight bearing, as tolerable, active, remove brace, aim for 0-90dg

Therapeutic exercises – Heel slides 0-90dg, quads setting, calf/h’sting stretches, SLR with brace on, resisted plantar flexion

4 – 8 weeks

Weight bearing – 4 wks open brace for ambulation (PWB only) if good quadriceps control and only up to 20kg weight

Brace – Unlocked for walking, remove for sleeping

ROM – Non weight bearing, as tolerable, active and active assisted, aim for full ROM

Therapeutic exercises – Progress above, remove brace for SLR if no extensor lag, cycle against low resistance if adequate ROM

8 weeks – 3 months

Weight bearing – No restrictions, if pain free. Wean off crutches when gait pattern is normal

Brace – Wean off brace

ROM – Aim to attain and maintain full ROM

Therapeutic exercises – Step ups and down, squats 0-45dg, leg press 0-60dg, hamstring curls, CKC terminal knee extensions, balance training, increase resistance on bike

3 – 9 months

Weight bearing – Full

Brace – None

ROM – Full and pain free

Therapeutic exercises – Progress CKC exercises, treadmill walking, swimming and cycling

Return to work

  • Sedentary work may be possible at 2-3 weeks
  • Non-sedentary work may be 3-6 months depending upon the demands of the work and the patient recovery

Return to driving

  • This is usually possible at 8 weeks, and is dependent upon the patient’s ability to use the foot pedals, and break without any hesitancy or weakness

Removal of the plate

  • If the plate is causing you symptoms, and/or future surgery is likely to be required, your surgeon may wish to remove the plate and screws at a suitable time. This will not usually be performed earlier than 18 months post surgery.