Cartilage repair surgery covers one damaged spot on a bone end

Microfracture uses marrow to cover one damaged spot

A surgeon may discuss repair when one patch of cartilage, the smooth bone covering, is gone. The damage needs to be limited to one clear area. The rest of your knee can't have the same broad wear.

Microfracture is an operation that makes tiny holes beneath the damage. Marrow comes through those holes and forms a scar-like covering. That covering isn't the same as the smooth cartilage you lost.

The first exam shows whether the damage is widespread

Your exam and X-ray can show whether one spot or the whole joint is worn. A doctor may need another scan before discussing an operation. You'll want clear details about recovery before making any choice.

QC Kinetix calls its non-surgical knee shots regenerative treatments. Its medical providers examine joints and discuss whether that care may suit you. PRP stands for platelet-rich plasma, a blood treatment given as a knee shot.

Staff spin your blood to gather platelets, which help with clotting and healing. They put that prepared blood back into the knee. It won't rebuild worn cartilage, and results can differ.

MACI uses your cells in a two-stage operation

MACI is a two-stage operation using cells from healthy knee cartilage. A laboratory grows the cells before a surgeon places them over the damage. It isn't a quick operation or a short recovery.

Before surgery, ask how long you'll need crutches. You'll also need to know how much weight the leg may carry. You may need help at home while those limits are strict.

Repair surgery doesn't replace wear across the knee

People often ask whether an operation can replace all worn cartilage. These operations repair one clear spot, not damage throughout the knee. They can't make a worn joint new again.

If soreness comes from broad wear, surgery may not make sense. Strength work, activity changes, and non-surgical care may help daily movement. You'll need an exam before comparing those choices.

Sources

1. MACI (autologous cultured chondrocytes on a porcine collagen membrane, Vericel; STN BL 125603) IS an FDA-LICENSED cell therapy - and its approved indication is narrow and specific: repair of symptomatic, single or multiple FULL-THICKNESS cartilage defects OF THE KNEE, with or without bone involvement, in adults. It is not approved for osteoarthritis. The existence of one licensed cartilage cell therapy for focal defects is the sharpest available way to show what a licensed 'regeneration' product actually looks like, and how far it is from an injection for a worn joint.

   US Food and Drug Administration, Center for Biologics Evaluation and Research — MACI (autologous cultured chondrocytes on porcine collagen membrane). FDA, 2024.

2. The SUMMIT randomized trial treated 144 patients (mean age 33.8, mean lesion 4.8 cm2) with at least one symptomatic focal cartilage defect (Outerbridge III/IV, >=3 cm2) of the femoral condyle or trochlea. Matrix-applied characterized autologous cultured chondrocytes (MACI) improved KOOS pain (37.0 to 82.5) and function significantly more than microfracture (pain 35.5 to 70.9) at 2 years, with histological and MRI assessment of the repair tissue. This is what a positive cartilage-repair trial looks like - in young patients with a discrete hole, not a worn joint.

   Saris D, et al. — Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Two-Year Follow-up of a Prospective Randomized Trial.. The American journal of sports medicine, 2014. DOI: 10.1177/0363546514528093.

3. Eighty patients with a single symptomatic chronic femoral condyle cartilage defect were randomized to autologous chondrocyte implantation or microfracture and followed 14-15 years. No significant difference in clinical scores emerged at long-term follow-up; there were 17 failures in the ACI group versus 13 in the microfracture group and more total knee replacements after ACI (6 versus 3). Fifty-seven percent of surviving ACI patients and 48% of surviving microfracture patients had radiographic early osteoarthritis (KL >=2).

   Knutsen G, et al. — A Randomized Multicenter Trial Comparing Autologous Chondrocyte Implantation with Microfracture: Long-Term Follow-up at 14 to 15 Years.. The Journal of bone and joint surgery. American volume, 2016. DOI: 10.2106/JBJS.15.01208.

4. FDA's public list of licensed cellular and gene therapy products is the checkable answer to 'is this FDA-approved?'. A product not on that list, and not being administered under an active IND, is not an approved therapy however it is described in a brochure. For orthopedics the list is short and its cartilage entry is MACI, indicated for focal full-thickness knee defects.

   US Food and Drug Administration, Center for Biologics Evaluation and Research — Approved Cellular and Gene Therapy Products. FDA, 2026.

5. The AAOS clinical practice guideline summary on SURGICAL management of knee osteoarthritis - the other end of the ladder, and the honest comparator for anyone told a biologic injection will let them avoid an operation.

   Srivastava AK, et al. — American Academy of Orthopaedic Surgeons Clinical Practice Guideline Summary of Surgical Management of Osteoarthritis of the Knee.. The Journal of the American Academy of Orthopaedic Surgeons, 2023. DOI: 10.5435/JAAOS-D-23-00338.

6. A JBJS systematic review screened 420 papers on intra-articular cellular therapy for knee OA and focal cartilage defects and found only SIX at Level III evidence or higher (4 Level II, 2 Level III), covering 300 knees, with wide variation in cell source, cell characterisation, adjuvant therapy and outcome assessment - meaning no consensus exists on indications, cell sources, preparation or delivery. Two products called 'stem cell therapy' at two clinics may share almost nothing.

   Chahla J, et al. — Intra-Articular Cellular Therapy for Osteoarthritis and Focal Cartilage Defects of the Knee: A Systematic Review of the Literature and Study Quality Analysis.. The Journal of bone and joint surgery. American volume, 2016. DOI: 10.2106/JBJS.15.01495.