Microfracture makes repair tissue in a damaged spot

Microfracture lets marrow reach damaged cartilage

Cartilage is the smooth coating over bone ends in a joint. It doesn't mend like skin because it has no blood supply.

During microfracture, small openings are made in the bone below the damage. Marrow then reaches that area and forms repair tissue over time.

The new tissue is called fibrocartilage, meaning tough, fibrous repair material. It isn't the same smooth cartilage that covered the bone before.

Early relief doesn't settle the long-term question

Some people improve after microfracture, especially during the earlier years. For others, function later drops or another operation becomes necessary as time passes.

That difference is why your own joint details matter. The damaged area's size, location, and depth can change the advice.

Your activity goals and earlier operations matter for years to come. Microfracture isn't one answer for every damaged cartilage area.

Other operations repair cartilage in different ways

Some operations move cartilage and bone from another area of the joint. Others use donor tissue or cartilage cells grown before another operation.

Each choice brings different recovery needs and limits. Widespread arthritis also calls for a different discussion than one damaged spot.

Ask what tissue the proposed operation is expected to leave behind. Then ask why that operation fits your joint better than another choice.

The first operation can affect later choices

Microfracture enters the bone under the cartilage damage. That bone change may matter if another operation is needed later.

Ask what options remain if the soreness returns. Learn how long protected movement and rehabilitation may last as well.

If you travel for surgery, ask where later checks will happen. Recovery needs to work after you return home.

An exam decides whether microfracture belongs in the talk

A public review can't show the damaged area's depth or location. It also can't tell whether the rest of your joint is stable.

Ask the person examining you to explain the joint findings plainly. You need the reason for surgery, not only its name.

If the knee locks, swells quickly, or becomes hot with fever, seek care promptly. Those symptoms need attention before a planned surgery discussion.

Evidence sources

1. The Cochrane review of surgical interventions for isolated cartilage defects of the knee in adults found only three randomised trials, all comparing mosaicplasty with microfracture, reporting 133 participants in total with a mean defect area of 2.8 cm2. It found NO randomised trials of allograft transplantation or drilling at all, judged every trial at high or unclear risk of bias, and rated the quality of evidence very low for every outcome.

   Gracitelli GC, et al. — Surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults.. Cochrane Database Syst Rev, 2016.

2. At 14 to 15 years, the Norwegian multicentre randomised trial of 80 patients with a single symptomatic femoral condyle cartilage defect found no significant difference between autologous chondrocyte implantation and microfracture on any clinical scoring system. There were 17 failures in the ACI group versus 13 after microfracture, and more total knee replacements had been needed after ACI (6 versus 3).

   Knutsen G, et al. — A Randomized Multicenter Trial Comparing Autologous Chondrocyte Implantation with Microfracture: Long-Term Follow-up at 14 to 15 Years.. J Bone Joint Surg Am, 2016.

3. At five years the same randomised trial reported nine failures (23%) in each arm and satisfactory results in 77% of patients, with no significant clinical or radiographic difference between ACI and microfracture and again no correlation between histology and outcome. One-third of all patients already had radiographic signs of early osteoarthritis five years after surgery.

   Knutsen G, et al. — A randomized trial comparing autologous chondrocyte implantation with microfracture. Findings at five years.. J Bone Joint Surg Am, 2007.

4. Sixty competitive athletes (mean age 24.3) with a symptomatic knee cartilage lesion were randomised to mosaic osteochondral autologous transplantation or microfracture. At a mean 37 months, 96% of the transplantation group had excellent or good results versus 52% after microfracture.

   Gudas R, et al. — A prospective randomized clinical study of mosaic osteochondral autologous transplantation versus microfracture for the treatment of osteochondral defects in the knee joint in young athletes.. Arthroscopy, 2005.

5. At 10 years in the same randomised athlete cohort, osteochondral autologous transplantation remained significantly better than microfracture, with 4 failures (14%) after transplantation versus 11 (38%) after microfracture. Both groups' scores had declined from their earlier peak, and Kellgren-Lawrence grade I changes were present in 25% of the transplantation group and 48% of the microfracture group.

   Gudas R, et al. — Ten-year follow-up of a prospective, randomized clinical study of mosaic osteochondral autologous transplantation versus microfracture for the treatment of osteochondral defects in the knee joint of athletes.. Am J Sports Med, 2012.

6. Among 321 consecutive patients treated with autologous chondrocyte implantation (522 defects), defects previously treated with a marrow stimulation technique failed at 26% versus 8% in defects with no prior penetration of the subchondral bone - a threefold higher failure rate. The order in which procedures are done changes what the later ones can achieve.

   Minas T, et al. — Increased failure rate of autologous chondrocyte implantation after previous treatment with marrow stimulation techniques.. Am J Sports Med, 2009.

7. A prospective cohort of 110 patients treated with microfracture for a focal chondral defect was evaluated at a median of 12 years. Scores improved significantly from baseline and did not differ from the 5-year results, but 43 patients had needed further knee surgery including seven knee replacements, 50 had a poor long-term outcome, and normal knee function was generally not achieved. The authors called for caution in recommending microfracture.

   Solheim E, et al. — Results at 10-14 years after microfracture treatment of articular cartilage defects in the knee.. Knee Surg Sports Traumatol Arthrosc, 2016.

8. In 102 patients with a single medial femoral condyle defect of 1 to 5 cm2, mosaicplasty produced clinically meaningful better Lysholm scores than microfracture at six months, one year, five years and ten years, but by 15 to 18 years the remaining eight-point difference was no longer statistically significant.

   Solheim E, et al. — Long-term clinical follow-up of microfracture versus mosaicplasty in articular cartilage defects of medial femoral condyle.. Knee, 2017.

9. A systematic review of 13 studies covering 821 athletes treated with microfracture in the knee found good or excellent results in 67%, return to sport in 66% at an average of eight months, return to competition at the pre-injury level in 67% of those - and declining function in 42% of athletes between two and five years after surgery.

   Mithoefer K, et al. — Clinical Outcome and Return to Competition after Microfracture in the Athlete's Knee: An Evidence-Based Systematic Review.. Cartilage, 2010.

10. In a prospective multicentre randomised trial, 47 patients with focal knee cartilage lesions (mean defect 3.6 cm2) received microfracture alone or microfracture covered with a type I/III collagen membrane (AMIC). All arms improved for the first two years, after which the microfracture group deteriorated progressively while both AMIC arms stayed stable to five years, with more complete MRI defect filling in the AMIC groups.

    Volz M, et al. — A randomized controlled trial demonstrating sustained benefit of Autologous Matrix-Induced Chondrogenesis over microfracture at five years.. Int Orthop, 2017.

11. The same 47-patient randomised trial reported at ten years: all three arms improved over the first two years, then the microfracture group deteriorated significantly while both AMIC arms remained stable. MOCART imaging scores, however, were comparable between the groups - the clinical divergence was not visible on the scan.

    Volz M, et al. — A randomized controlled trial demonstrating sustained benefit of autologous matrix-induced chondrogenesis (AMIC(®)) over microfracture: 10-year follow-up.. Eur J Orthop Surg Traumatol, 2024.