An Athlete’s Guide to Knee Cartilage Damage & Repair

All athletes are familiar with what it means to get injured—and you may fear that a cartilage injury might permanently end your time on the court or field. Fortunately, there are treatment options for athletes looking to make a comeback.

Orthopedic surgeon Dr. Brian Domby explains what patients should know about cartilage injuries, including information on a procedure called MACI, an FDA-approved procedure that uses your own cells to regenerate cartilage.

About Cartilage Damage

Cartilage is the tough, flexible layer of tissue found in our joints. Cartilage is why we can bend our knees and elbows so smoothly and how our bodies can absorb shock when we run and jump.

Unfortunately, cartilage is easy to damage—a wrong twist, a sudden fall, or even just wear and tear over time can all result in cartilage injuries. These injuries can’t heal naturally because cartilage doesn’t receive blood flow to repair itself. Cartilage injuries are most common in the knee, though they can happen in other joints, too. 

Symptoms of a Cartilage Injury

Signs and symptoms of a cartilage injury might appear gradually over time or might occur suddenly after an accident or fall. Be on the lookout for:

  • Joint pain, sometimes even when you’re sitting or laying down
  • Stiffness, which can make it hard to bend your knee or elbow
  • Swelling, redness, and a joint that may feel warm to the touch
  • Joint weakness or instability
  • A clicking, grinding, or catching feeling in your knee

If it’s hard to do daily activities because of pain or you can’t walk or put weight on your leg, it’s time to contact an orthopedic surgeon.

Can damaged cartilage repair itself?

Cartilage can’t repair itself after it’s been damaged because it doesn’t have a source of blood flow to promote healing. Some chondrocytes (cartilage cells) can regenerate naturally, but most injuries need treatment from a medical professional to heal.

Who’s at risk of cartilage damage?

Anyone can potentially damage their cartilage, but injuries are most common in athletes who put a lot of stress on their joints. Older adults who have arthritis are also at risk.

Athletes in high-impact sports—like football, basketball, soccer, and tennis—are often injured due to accidents on the court or field or poor form when making a maneuver. Injuries are often caused by:

  • Hitting your knee directly on a hard surface
  • Twisting or bending awkwardly
  • A bad fall or poor landing after jumping
  • Overextending or straining your knee
  • Gradual wear-down from repetitive motions or overuse

Treatment Options for Cartilage Injuries

Treatment will depend on the severity of your injury. Some mild injuries may heal on their own with rest, but always be sure to consult with a doctor if you’re concerned about pain. If left untreated, cartilage damage can lead to severe joint pain and arthritis over time.

Treatment options include:

  • The RICE method. RICE stands for rest, ice, compression, and elevation. This method involves taking a break from sports and exercising for a few days to let minor strains and sprains heal, though it can’t repair major injuries. Learn more about the RICE method from the Mayo Clinic.
  • Physical therapy. Physical therapy strengthens the muscles around your joints, which helps reduce pain and prevent future injuries.
  • Injections. Platelet-rich plasma (PRP) injections can help manage pain and promote healing using platelets taken from your own blood.
  • Surgery. When a cartilage injury can’t heal on its own, your doctor may recommend surgery to repair the damage. The kind of surgery that will work for you will depend on the severity of your injury.

If rest doesn’t resolve your symptoms after a few days or your pain interferes with your daily life, talk to an orthopedic doctor. They can perform exams and order imaging scans (like an x-ray or MRI) to better look at the injury and make a treatment plan.

Types of Surgery for Cartilage Injuries

There are many different surgeries designed to fix cartilage. Your orthopedic surgeon will recommend what’s best for you after evaluating your injury, medical history, and activity level.

  • Microfracture. This technique involves poking small holes in the bone beneath cartilage. These holes let in a source of blood flow, which promotes healing in the cartilage cells.
  • Osteochondral transfer system (OATS). Also called mosaicplasty, this involves taking a piece of healthy cartilage from your knee and using it to replace a damaged piece. Your surgeon may use tissue from a donor’s knee if there isn’t enough healthy tissue from your knee to use.
  • Meniscus repair. If you’ve severely damaged your meniscus (the shock-absorbing cartilage between your shin and thigh), your surgeon may try to repair it or transplant a healthy meniscus from a donor.
  • Autologous chondrocyte implantation (ACI). For an ACI procedure, your surgeon will take a sample of your cartilage cells to grow them into a custom-made implant. ACI is often recommended for younger athletes.

MACI Surgery: Replacing Cartilage with Your Own Cells  

As mentioned above, one way to repair cartilage is a procedure called autologous chondrocyte implantation (ACI). This technique involves taking a sample of your cartilage cells, growing those cells in a lab, and then implanting them back into your knee.

Dr. Domby is one of the few orthopedic surgeons in the Tampa Bay area specializing in repairing cartilage through matrix-induced autologous chondrocyte implantation (MACI). MACI is the third-generation ACI, which is considered the gold standard of cartilage regeneration based on over 25 years of research and data.

For athletes, MACI is an effective way to heal damage and return to full activity after a cartilage injury. It can provide long-lasting relief and restore function to your knee. If your doctor determines you’re a candidate for MACI, most commercial insurance will cover the cost of the procedure.

A graphic explaining the MACI acronym

About the MACI Process

MACI is a multi-step process. It requires two procedures over one to two months. Here are the basic steps:

  1. Taking a cartilage biopsy. Dr. Domby will take a small sample of cartilage from a non-weight-bearing surface of your knee through a small arthroscopic incision. This step takes around 30 minutes.
  2. Growing your cartilage in a lab. Dr. Domby will send the piece of your cartilage to an FDA-licensed lab. In this lab, your cartilage cells (chondrocytes) will be grown to cover a special scaffold structure (called a collagen matrix) to make a custom implant called a MACI graft that fits your cartilage defect exactly. It takes about a month to grow.
  3. The implantation procedure. Once the cells are ready, Dr. Domby will implant the MACI graft into your knee. After the implant is done, it’ll take around 6-9 months for your cells to grow new cartilage and reach full maturity. This procedure is done through a small incision called a mini-arthrotomy.

Read more about each step of MACI.

After surgery, you’ll participate in physical therapy to strengthen your leg muscles and restore function to your knee. The exact recovery timeline varies from patient to patient.

You won’t be able to place any weight on your knee for a few weeks after surgery. It may take about 6 -7 weeks to be able to walk entirely without crutches and at least 9 months before your cartilage is fully healed. It may take 12 months before you’re able to participate in high-impact sports.

Read more about the MACI rehabilitation process.

Safety & Risks

MACI is a relatively safe procedure, but there are always risks associated with any surgery, including infection, blood clots, and nerve damage.

Some specific risks of the MACI procedure include:

  • Joint pain
  • Tendonitis
  • Back pain
  • Knee stiffness
  • Joint swelling

Your doctor will discuss safety with you before surgery. Following your doctor’s instructions after the procedure and regularly attending physical therapy can help reduce your risk of long-term issues.

Talk to a MACI Surgeon Today

Cartilage damage doesn’t have to mean the end of your athletic career. If you’re struggling with joint pain and inflammation that’s impacting your ability to do the things you love, it’s time to talk to an orthopedic surgeon.

Call (813) 979-0440 or click here to schedule a consultation with Dr. Domby at an office in Brandon, North Tampa, or Wiregrass. Telemedicine appointments are also available. Whether it’s through physical therapy, pain management, or a surgical procedure like MACI, Dr. Domby is here to help you get moving again.

dr domby tampa fl orthoAbout Brian Domby, MD

Dr. Brian Domby is a board-certified orthopedic surgeon and one of the only surgeons certified to perform MACI in the Tampa Bay region. Dr. Domby is passionate about helping his patients return to active life, whether they’re professional players, high-school athletes, or at-home exercise enthusiasts.

In addition to caring for Florida Medical Clinic patients, Dr. Domby is a team physician for the Tampa Bay Lightning, USA Women’s Hockey, and US Figure Skating.

Disclaimer: This blog is not intended to substitute professional medical advice. Every patient is different, so talk with your orthopedic doctor to learn what treatment options are best for you.


Orthopaedics, Sports Medicine & Spine

About this author.


Brian C. Domby, MD

Orthopaedic Surgery & Sports Medicine, Knee & Shoulder

  • Accepting new patients

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