Microfracture for Cartilage Defects

Microfracture is a surgical technique that has been developed to treat cartilage defects. 

A Full Thickness Cartilage Defect on the Kneecap

It is a common procedure used to treat patients with full thickness damage to the articular cartilage that goes all the way down to the bone. 

This arthroscopic procedure was first introduced about 20 years ago by Dr Richard Steadman as a treatment method that uses the body’s own healing abilities and provides an enriched environment for tissue regeneration on the cartilage surface. 

Since its development, the microfracture procedure has been used by its originator to treat more than 2000 patients. 

Of these patients, 75 to 80% experienced significant pain relief and improvement in the ability to perform daily activities and participate in sports. 

Fifteen percent noticed no change, and five percent continued to have joint deterioration. 

How Does It Work? 

Microfracture creates small holes in the bone using a sharp tipped metal awl. These small holes become a channel through the surface layer of bone, called the subchondral bone, which is hard and lacks good blood supply. By penetrating this hard subchondral bone layer, a microfracture channel allows the deeper, more vascular bone to access the surface layer hence forming a super clot. This deeper bone has more blood supply, and the cells can then get to the surface layer and stimulate cartilage growth. 

The new tissue is a “hybrid” of articular-like cartilage plus fibrocartilage. Experience shows that this hybrid repair tissue is durable and functions similarly to articular cartilage.

Who Can Benefit? 

  • Patients with painful contained full thickness cartilage defect.
  • The defect size should be less than 2cm in diameter.
  • No lower limb malalignment – those with bowed knees should not have this technique performed for medial knee joint weight-bearing area defects.
  • Younger patients have better results – ? better healing potential.
  • Compliant with post-operative rehabilitation and physiotherapy.

Who Will Not Benefit? 

  • Extensive or global cartilage defects.
  • Unstable knee from ligament injury e.g. anterior cruciate ligament tear.
  • Poorly aligned knees that may overload the painful compartment.
  • Severely overweight patient.
  • Poorly motivated patient who will not follow post-operative rehabilitation and physiotherapy.

Surgical Technique 

The patient usually presents with pain in the knee associated with swelling. The diagnosis of a full thickness cartilage defect can be confirmed using an MRI scan.  

The surgery is usually performed under general anaesthesia and the procedure involved minimally invasive keyhole surgery to the knee joint. This procedure is called knee arthroscopy

Using 2 tiny holes in front of the knee, the surgeon is able to insert a camera into the joint to carefully access the cartilage damage.  The other tiny hole allows the surgeon to introduce the metal awl to perform the microfracture. 

This is a video of my patient undergoing microfracture for a patella ulcer: 

The key to successful microfracture is the post-operative rehabilitation

Dr Richard Steadman who invented this technique has stressed the importance of post-operative rehabilitation in order to for other surgeons to reproduce the success that he has had with this technique. 

Dr Chang with Dr Richard Steadman

Dr Steadman has taught us that: 

Rehabilitation Protocol for Patients with Chondral Defects on the Femur or Tibia 

  • The patient is started on a continuous passive motion (CPM) machine immediately in the recovery room. Ideally, the patient should use the machine for 6 to 8 hours every 24 hours. Range of motion is increased as tolerated until full range of motion is achieved with the machine.
  • If a CPM machine is not used, the patient begins passive flexion/extension (straightening and bending) of the knee with 500 repetitions three times a day.
  • The use of crutches, with only light touch-down weight allowed on the involved leg, is prescribed for 6 to 8 weeks. Patients with small defect areas (less than 1cm in diameter) may be allowed to put weight on the leg a few weeks sooner.
  • Brace use is rarely recommended for patients with chondral defects on the femur or tibia.

Limited strength training also begins immediately after microfracture surgery. 

  • Standing one-third knee bends with a great deal of the weight on the uninjured leg begin the day after surgery.
  • Stationary biking without resistance and a deep-water exercise program begin 1 to 2 weeks after surgery.
  • After 8 weeks the patient progresses to full weight-bearing and begins a more vigorous program of active knee motion.
  • Elastic resistance cord exercises can begin about 8 weeks following surgery.
  • Free weights or machine weights can be started when the early goals of the rehabilitation program have been met, but no sooner than 16 weeks after surgery.
  • Patients must not resume sports that involve pivoting, cutting, and jumping for 4 to 6 months after a microfracture procedure. Full activity may be resumed once the physician has examined the knee and given approval for the patient to return to sports activity.

Rehabilitation Protocol for Patients with Patellofemoral Chondral Defects 

  • All patients treated with microfracture for patellofemoral defects must use a brace set for 0° to 20° of flexion for at least 8 weeks. It is essential to limit compression of the new surfaces in the early postoperative period, so that the maturing marrow clot will not be disturbed. The brace should be worn at all times except when passive motion is allowed.
  • Patients are placed into a CPM machine immediately following surgery. The goal is to obtain a pain-free and full passive range of motion soon after surgery during those periods when the brace is removed.
  • When the patient wears a brace, strength training is allowed, but only in the 0° to 20° range immediately after surgery in order to limit compression of the affected chondral surfaces. The joint angles of these patients are observed carefully at the time of surgery to determine where the defect makes contact with the opposing surface, either on the patella or on the trochlear groove of the femur. These areas are avoided during strength training for approximately 4 months.
  • Patients are allowed to put weight on the involved leg as tolerated, but it must be limited to the angles of flexion that do not compress the treated surfaces. For this reason the patient must wear a brace locked in limited flexion.
  • After 8 weeks, the knee brace is gradually opened to allow increased flexion of the knee, a process that takes about a month. Brace use is generally discontinued at about 12 weeks. Some patients, however, like to continue to wear the brace for strenuous exercise for a few more months up to about 6 months.
  • After brace use is discontinued, strength training advances progressively.

In order to enhance the formation of cartilage in the microfractured area of the knee, I have added autologous stem cell injections.  The stem cells are cultured in the laboratory after harvesting the blood from the bone marrow at the time of the surgery. 

The cells are then injected back into the knee joint at 3 weeks after the surgery.  This is an experimental technique and the success rates are not known. 

Injection of Stem Cells to Promote Cartilage Formation

For more information on microfracture treatment or for an assessment of your knee pain, please contact us at 683-666-36 or email hcchang@ortho.com.sg.

Visit us at www.ortho.com.sg

11 Responses to “Microfracture for Cartilage Defects”
  1. Kathy says:

    I had a microfracture procedure to my medial knee about 9 days ago. It was a rather large lesion (quarter sized) that was removed and the microfracture done at that point. I have been allowed to weight bear 85% for the last week. I have read in this article and others that weight bearing should not be allowed for 4-6 weeks. I did not use a CPM and have been moving my knee but no where near 1500 times/day! There is still swelling in my knee and it is quite stiff when I bend it. I can bend it 90 degrees without much trouble but beyond that is somewhat difficult, I am thinking because of the excess fluid in the joint. I have been on a stationery bike (no resistance) about 10 minutes 1-2 times/day. That actually feels pretty good. Does all this sound typical or should I be concerned about weight bearing at this stage? Can you explain the reason for not weight bearing within the first month following the surgery?

  2. The original rehab protocol for microfracture requires 6 weeks of protected weight bearing as well as emphasis on moving the knee. This applies to cartilage lesions in the weight bearing portions of the knee. Dr Steadman obtained good results with this post surgery regime.

    Many surgeons have modified this rehab protocol to suit their preference. However there really isn’t any published results on micro fracture with rehab protocols deviating from Dr Steadman’s.

    Hence I tend to advise my patients to follow this protocol as closely as possible. For smaller lesions, I usually let them walk without crutches.

  3. scott says:

    I had Microfracture completed 4/22/11. On my post op visit, my orthopedic stated the lesion was very large and that I should consider looking at “another” option, such as a surgical plug/graft from a cadaver. He referred me to another orthopedic for a second opinion as that surgery was very technical. The lesion size was 4cm x 3cmx2.5 cm. The second opinion was to wait and see how i react to the microfracture repair before considering any other option. Any insight would be appreciated. I am currently in week 2 of my non weight bearing stage.


    • I will assess you lower limb mechanical axis to see if the weight bearing axis is in the centre of the knee or to the side of the cartilage ulcer. If there is malalignment, consider an osteotomy.

      For such a large lesion, autologous chondrocyte implantation can be considered.

  4. silje says:

    I am having a Microfracture operation on my left knee due to Patellofemoral Chondral Defects. I am struggling to find good information about this procedure, and the time after the operation, do you have any tips for good internet links? I am wondering how the time after the operation will be. I have an still-sitting office job, can I go straight back to work after operation, or do I need to stay at home (I want to work)? I am told I need to wear a brace for 6-8 weeks after operation, but can I put pressure on the fot? I have plans for the holiday, involving travelling by plane, is that possible?

    I hope you can help me. Thanks:)

    • Jez Heber says:

      I had this op in June 2011. The brace is restrictive but I found that I could adjust to it for most things. I had a holiday in Iceland booked for August and I coped with the plane and lurched around sufficiently well to be able to enjoy the holiday still. You can bear weight but just within a very small range of flexion. I took one pedal off my bike and attached a toe-clip to the other and so I could still get around and I developed marvelous quads on the ‘off-leg’. Sleeping was one of the worst difficulties, to be honest. That brace is not a complient bed fellow! Now I’m working on building up the operated leg again which is a slow process but I hope to be playing sport again in the summer.
      Good luck with the op. Expect a good deal of frustration over the months to come but push through it and do whatever excercises you can to maintain your quads on that leg as that’s the biggest challenge of the rehab once you’re out of the brace.

  5. Jez Heber says:

    I had microfractur esurgery on my patella 5 months ago and am just starting to use the knee within the range that involves the lesion.
    I get a good bit of pain behind the patella when I put my full weight on it and I assume that it’s because it’s still healing. (I’m 45 so I appreciate that it will be slower than for a 20 year old!)
    Is this anything to worry about and should I be avoiding any exercise that give me pain?

    • It is common to have aches and pains after this surgery. Even though it is 5 months since your procedure, the kneecap control by your thigh muscles may not be perfect and it can lead to some pain intermittently. I would persevere with physical therapy and wait longer before saying that it did not work. Avoid excessive stair climbing and squatting if possible.

      • Jez Heber says:

        Thanks. I ppreciate you taking the time to reply. The knee is continuing to improve with maltracking being the main problem. I’m reconciled to it just taking a lot longer than I had initally hoped to get back to full fitness.

  6. I had microfracture surgery 5 months ago on a weight bearing area on the inside of my right knee. The level of pain I have, even when walking on the flat is worse than before the procedure. I have pain at the site every time I plant my foot down. I am unable to climb the stairs properly either. I am 46 years of age and want to know how long i should leave things before getting back in touch with the consultant.

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