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What is Cartilage Cell Implantation?

Cartilage cell implantation is a technique of transplanting healthy cartilage cells to replace damaged cartilage cells and restore normal functioning of the joint. It is usually performed on the knee joint but may also be used to treat the shoulder and ankle joints.

Articular or hyaline cartilage is the white tissue lining the ends of bones that form joints. It acts as cushioning material and helps in the smooth gliding of bones during movement. Normal wear-and-tear or injury can damage and cause defects in the cartilage, resulting in irregular articular surfaces that interfere with movement, causing pain, swelling, and disability.

Autologous chondrocyte implantation (ACI) is the most common form of cartilage cell implantation that helps to regenerate articular cartilage in a damaged or diseased area of the joint by implanting cartilage cells. The ACI technique has been used extensively and has achieved remarkable outcomes, both with regard to cartilage repair as well as assisting patients returning to their previous activity levels.

Indications for Cartilage Cell Implantation

Cartilage cell implantation is indicated for cases of mild-to-moderate cartilage loss where joint replacement is not recommended. Ideally, you should meet the following criteria: 

  • Young and active individual between 16 and 45 years of age 
  • Do not have conditions such as rheumatoid arthritis or severe osteoarthritis that complicate joint health
  • Have sustained a single lesion or injury to the cartilage
  • Are not obese 
  • Are willing to participate in extensive postoperative rehabilitation

Preparation for Cartilage Cell Implantation

Preoperative preparation for cartilage cell implantation will involve the following steps:

  • A thorough examination by your doctor is performed to check for any medical issues that need to be addressed prior to surgery.
  • Depending on your medical history, social history, and age, you may need to undergo tests such as bloodwork and imaging to screen for any abnormalities that could threaten the safety of the procedure.
  • You will be asked if you have allergies to medications, anesthesia, or latex.
  • You should inform your doctor of any medications, vitamins, or supplements that you are taking.
  • You should refrain from medications or supplements such as blood thinners, aspirin, or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
  • You should refrain from alcohol or tobacco at least a week before and 2 weeks after surgery.
  • You should not consume solids or liquids at least 8 hours prior to surgery.
  • Arrange for someone to drive you home after surgery.
  • A written consent will be obtained from you after the surgical procedure has been explained in detail.

Procedure for Cartilage Cell Implantation

Cartilage cell implantation is mostly performed arthroscopically under regional or general anesthesia as follows:

  • Small incisions called portals are made around the joint. 
  • A viewing scope and surgical instruments are inserted into the portals. 
  • A saline solution is used to expand the joint and improve visualization. 
  • The images from the scope are sent to a video monitor where your surgeon can view the inside of your joint. 
  • Specialized surgical instruments are used to remove the damaged cartilage. 
  • The area is then prepared to receive the cartilage implant.

Autologous chondrocyte implantation (ACI) involves the removal of healthy chondrocytes (articular cartilage cells) from your own body and implanting them into the damaged region. These cells subsequently develop and constitute new articular cartilage. The procedure is accomplished in 2 stages:

  • The initial stage is an arthroscopic procedure where healthy cartilage is harvested from a non-weight bearing joint of your own body and sent to the laboratory, where the cartilage cells are extracted and cultured (multiplied) for a period of 3 to 5 weeks. 
  • In the next stage, an open surgery (arthrotomy) is performed where the dead joint tissue is removed, and the defect prepared appropriately. A piece of membrane called periosteum that lines bone surfaces is obtained, usually from the tibia, and sewn over the defect and sealed with glue. Your doctor then injects the cartilage cells under the membrane into the defect where they grow and mature to form new cartilage.

Other variants of cartilage cell implantation include the DeNovo graft and BioCartilage, which use pre-prepared human cartilage graft material. These procedures can be performed in one stage as they do not require harvesting of healthy cartilage tissue.

The DeNovo graft consists of pieces of viable cartilage in a storage media. Similar to ACI, the damaged cartilage area is prepared and sized. The graft is then prepared with a fibrin sealant and placed on the defect. The sealant precludes the need of a periosteal membrane.

BioCartilage consists of dehydrated cartilage, which is introduced along with platelet-rich plasma (concentrated blood component, which enhances healing) on the defects after a technique called microfracture is performed. Microfracture involves the creation of multiple holes at the damaged site to introduce blood supply and stimulate new cartilage to grow. The BioCartilage and platelet-rich plasma further promote cell growth and healing.

Postoperative Care and Instructions

In general, postoperative care instructions and recovery after cartilage cell implantation will involve the following:

  • You will be transferred to the recovery area where your nurse will closely observe you for any allergic or anesthetic reactions and monitor your vital signs as you recover.
  • You may notice pain, swelling, and discomfort in the operated area. Pain and anti-inflammatory medications are provided as needed.
  • You will be provided with assistive devices such as crutches with instructions on restricted weight-bearing for a specified period of time. You are encouraged to walk with assistance as frequently as possible to prevent blood clots.
  • Keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
  • Refrain from strenuous activities or lifting heavy weights for at least 2 to 3 months. Gradual increase in activities over a period of time is recommended.
  • An individualized physical therapy protocol will be designed to help strengthen joint muscles and optimize joint function.
  • You will be able to return to your normal activities in a month or two; however, return to sports may take 9 to 12 months or longer.
  • A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

Cartilage cell implantation is a relatively safe procedure; however, as with any surgery, there are risks and complications that could occur, such as:

  • Bleeding 
  • Blood clots or deep vein thrombosis (DVT)
  • Infection
  • Joint pain/swelling/stiffness
  • Numbness around the incisions
  • Injury to vessels, nerves, or healthy cartilage
  • Allergic/anesthetic reactions