Cartilage Preservation & Restoration

The most common type of cartilage is hyaline which is found in our joints.  Hyaline cartilage is the white soft substance at the ends of our bones that allows for motion at our joints with little friction. Biologically it’s made of many materials including water, proteoglycans, and collagen. These materials come together in a way to give it viscoelastic properties that allows it to provide support while remaining flexible. The best analogy for cartilage would be comparing it to the rubber on tires. Just like the rubber on your car tires, cartilage can be injured and can lose its thickness with wear and tear.

Who is a candidate for cartilage preservation and restoration?

Generally speaking, patients with isolated areas of cartilage damage are candidates for cartilage preservation and restoration. As long as the other areas of the knee have good cartilage, then there are a variety of treatment options that can be performed to help restore the areas with damaged cartilage.

What are the signs and symptoms of damaged cartilage?

Localized pain is one of the most common symptoms of damaged cartilage. A common sign of cartilage damage is when a higher amount of body weight placed on the joint elicits more pain. For example, you may have no knee pain swimming or using a bike, but as you begin to walk or run on solid ground it begins to hurt more. Most commonly, cartilage damage manifests in difficulty and severe pain walking up and down stairs.

How can cartilage damage be diagnosed?

Cartilage damage can be diagnosed based on your history and physical exam. Eliciting pain when your physician presses on your bone at the joint (joint line tenderness) is a common finding. Standing x-rays can help identify cartilage damage if it affects an entire compartment of your knee, for example, the inside/ medial, outside/ lateral, or under your kneecap/ patellofemoral. However, x-rays are not good at showing isolated areas of cartilage damage. Cartilage damage is best seen on MRI or during diagnostic arthroscopy. In the appropriate candidate, an in-office diagnostic arthroscopy can be performed with relatively little discomfort to accurately diagnose a cartilage injury.

What are the stages of cartilage injury?

Cartilage injury is generally classified using the Outerbridge classification. The stages of cartilage damage are called chondromalacia, literally translating in Latin as “bad cartilage.”

• Grade I Chondromalacia: soft and swollen cartilage
• Grade II Chondromalacia: Partial-thickness cartilage defect with fissures on the surface that do not reach the underlying bone
• Grade III Chondromalacia: Fissuring cartilage defect that goes down to the bone
• Grade IV Chondromalacia: Exposed bone without any overlying cartilage

What types of cartilage restoration options are there?

Most modern cartilage restoration techniques involve an initial diagnostic arthroscopy to accurately measure the lesion and perform a cartilage biopsy, followed by a second-stage surgery to perform one of three main options.

Autologous Chondrocyte Implantation
Osteochondral Autograft or Allograft Transplantation
De Novo Cartilage Transplantation

Which option for cartilage restoration is the best?

Depending on the size and location of your cartilage lesion, your surgeon will make the best recommendation based on your specific pathology. Feel free to read each individual section on the above techniques to learn more.

Why don’t you perform microfracture?

Microfracture was a simple procedure that can be done in one surgery. The idea was to stimulate the underlying bone marrow by making tiny fractures in the bone in order to grow fibrocartilage over an area of cartilage damage. Unfortunately, the outcomes with microfracture are not good. Patients generally continue to have pain and poor function after this procedure. In addition, going back later to perform one of the other techniques of cartilage restoration generally doesn’t do as well either. For that reason, cartilage implantation and transplantation are the best options we have for cartilage restoration.