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Microfracture

What is microfracture?

Microfracture is a surgical technique used during arthroscopic (keyhole) surgery to help treat small areas of damage on the surface lining of the joint (chondral surface). Small holes are created in the surface of the bone that is damaged.

This treatment was popularized in the 1980’s by Richard Steadman, an Orthopaedic Surgeon in Vail, Colorado.

How does microfracture work?

Small holes are made in the damaged surface of the bone. The underlying bone bleeds forming a clot, this creates scar like tissue over the surface of the damaged bone.

The normal surface lining of the end of the bones is made of hyaline cartilage that has a highly specialized structure and function. Microfracture creates bleeding and stimulates the growth of fibrocartilage (which is normally found in scar tissue). This fills the defect.

The fibrocartilage does not have the same shock absorbing properties as hyaline cartilage and is not as resilient.

How is microfracture performed?

Click here to watch a video outlining the procedure

It is performed during arthroscopy surgery (key hole surgery)

The damaged chondral surface (articular cartilage) is prepared by removing loose or damaged areas. A small sharp pick (awl) or drill is used to create small holes in the surface of the underlying bone. Bleeding occurs from these holes.

Microfracture

It is important that bleeding occurs from the holes.

Who is a good candidate for microfracture?

  • Intrusive symptoms (pain, swelling , locking , giving way).
  • Damage less than 2cm in diameter.
  • Full thickness damage of the articular cartilage.
  • Active patients prevented from undertaking their chosen activity.

Who is not a good candidate for microfracture?

  • Patients with widespread arthritis.
  • Patients unwilling to participate in the rehabilitation.
  • If the chondral damage is not full thickness.
  • If there is poor lower limb alignment.

Does microfracture work?

Yes – sometimes.

Microfracture can be extremely successful if done in the correct patient for the correct reasons. Unfortunately like all surgery there is no guarantee of success even then.

The normal surface lining of the end of the bones is made of hyaline cartilage that has a highly specialized structure and function. Microfracture stimulates the growth of fibrocartilage which is normally found in scar tissue. This does not have the same shock absorbing properties as hyaline cartilage and is not as resilient and so will not last as well.

What does the rehabilitation involve?

Rehabilitation depends on the location, size of the defect and whether any other procedures were performed at the same time.

Weight bearing

The microfracture area is very fragile especially during the early weeks and the potential for healing and producing healthy tissue will be compromised if excessive forces are applied.

How to limit these forces depends on the location of the microfracture.

If it is on the end of the tibia (shin bone) or femur (thigh bone), the force is limited by not putting weight through the leg by using crutches.

If the microfracture is behind the patella (knee cap) or within the groove for the patella (trochlea), knee bend is restricted by the use of a brace. The range of movement of the knee is restricted so the microfractured area does not come in contact under load.

These restrictions are maintained for 8 weeks and then the load is gradually increased. It can take up to 6 months to return to moderate activity and sport.

Range of movement

Controlled range of movement exercises are started very soon after the operation. A Continuous Passive Movement (CPM) machine is used to move the leg. This machine moves the knee for you so that minimal force is put across the joint. This should be used 6-8 hours a day for the 8 weeks.

If a CPM is not available a static bike can be used. Make sure there is only minimal resistance when pedalling. Use for 15-20 minute, 3 times a day. A pedal exerciser can be used if a static bike is not available.

This early range of movement is thought to stimulate healthy cartilage growth.

It is important that the knee regains full range of movement, usually by the third week after surgery.

What is the specific patella microfracture post operative management?

  • Brace fitted immediately after surgery to restrict range of motion.
  • Brace worn at all times except when undertaking movement exercises.
  • Full weight bearing is allowed as tolerated.
  • Cold therapy such as cryocuff or ice is used to decrease swelling.
  • Controlled range of movement exercises are started very soon after the operation. A Continuous Passive Movement (CPM) machine is used to move the leg. This machine moves the knee for you so that minimal force is put across the joint. This should be used 6-8 hours a day for the 8 weeks. If a CPM is not available a static bike can be used. Make sure there is only minimal resistance when pedalling. Use for 15-20 minute, 3 times a day. A pedal exerciser can be used if a static bike is not available. It is important that the knee regains full range of movement, usually by the third week after surgery.
  • After 8 weeks range of movement is gradually increased.
  • Exercises progressed under supervision of a physiotherapist to restore range of movement, strength, balance and confidence.
  • No running for 4-5 months
  • No sports involving jumping, high impact or cutting for 6 months.

What is the specific tibia/femoral post operative management?

  • Non weight bearing on crutches for 8 weeks.
  • Cold therapy such as cryocuff or ice is used to decrease swelling.
  • Controlled range of movement exercises are started very soon after the operation. A Continuous Passive Movement (CPM) machine is used to move the leg. This machine moves the knee for you so that minimal force is put across the joint. This should be used 6-8 hours a day for the 8 weeks. If a CPM is not available a static bike can be used. Make sure there is only minimal resistance when pedalling. Use for 15-20 minute, 3 times a day. A pedal exerciser can be used if a static bike is not available. It is important that the knee regains full range of movement, usually by the third week after surgery.
  • Achieve full range of movement as soon as possible after surgery, usually by the third week.
  • Strengthening exercises as instructed by your physiotherapist.
  • After 8 weeks, wean of crutches, gradually increase to full weight bearing.
  • Exercises progressed under supervision of a physiotherapist to restore range of movement, strength, balance and confidence.
  • No leg extension or free weights in the gym until 16 weeks.
  • No running for 4-5 months.
  • No sports involving jumping, high impact or cutting for 6 months.

What is CPM?

Continuous passive motion is a machine that bends and straightens you knee without you having to use your muscles.

It should be used for 6-8 hours a day for 8 weeks.

There is only some scientific evidence for its use but is reported to improve the quality of the scar tissue formed after microfracture.

To avoid paying VAT you will need to hire the machine yourself. The company will arrange delivery and confirm the price.

Normally it is best to have the machine delivered to the hospital were the physiotherapists will fit it for you after surgery.

Please check whether your insurance company will cover the cost of the CPM.

Phoenix Healthcare Products LTD is the name of one of many companies that hire CPM machines – tel 01949 838 444.