Cartilage reconstruction

What is cartilage reconstruction?

Cartilage reconstruction is surgery to repair damaged cartilage, the smooth tissue that cushions your joints, most often in the knee. It replaces or regenerates the missing cartilage using cells from your own body, helping to relieve pain and protect the joint from further damage.

What conditions does it treat?

Cartilage reconstruction treats damage to the cartilage inside a joint, usually caused by an injury, such as a sports injury, or by general wear and tear. Cartilage has very little ability to heal itself, since it has no blood supply, so an untreated defect tends to grow larger over time and can lead to early osteoarthritis.

Cartilage injury and degeneration together are among the most common musculoskeletal problems worldwide, affecting an estimated 500 million people. Cartilage reconstruction is generally aimed at younger, more active patients with a focal area of damage, rather than the widespread wear seen in older patients with established osteoarthritis, who are more often treated with joint replacement instead.

What are the benefits of having cartilage reconstruction?

Cartilage reconstruction can relieve pain, restore movement and help you get back to everyday activities. There is generally a high success rates, seeing healing of the joint, pain relief and restored function.

Because it repairs your own joint rather than replacing it, cartilage reconstruction can also delay or avoid the need for a joint replacement. This particularly benefits younger, more active patients, since joint replacements in this group often wear out sooner because of the higher demands placed on them.

Are there different types or surgical approaches?

There are several approaches to cartilage reconstruction, and your surgeon will recommend the one that suits your injury, age and activity levels.

• two-stage autologous chondrocyte implantation (ACI): a small sample of your healthy cartilage is taken by keyhole surgery, then grown and multiplied in a laboratory for several weeks before being implanted back into the damaged area in a second, open operation. This is considered the gold standard for cartilage defects in the knee and has been used for more than 20 years
• single-stage bone marrow or stem cell techniques: cells are taken from your own bone marrow, usually from the pelvis, using a needle, then concentrated and implanted into the joint in a single operation, needing only one operation and one hospital stay
• autologous matrix-induced chondrogenesis (AMIC): this combines a technique called bone marrow stimulation with a collagen membrane, which covers the defect and gives the healing cells a protected scaffold to grow within
• autograft transplantation: healthy cartilage and bone are taken from another part of your own joint and moved into the damaged area, which works well for smaller, focal areas of damage, particularly in younger patients

If your cartilage damage is linked to joint misalignment, your surgeon may combine cartilage reconstruction with a realignment operation, aiming to regenerate the joint without needing an artificial implant.

What happens before the operation?

You'll usually need a referral from your GP or another specialist to be seen at a specialist cartilage clinic. At your consultation, you'll be asked about your medical history, symptoms and any concerns, and your surgeon will discuss whether further tests, such as scans, are needed to assess the size and location of your cartilage damage.

Your surgeon will talk you through which approach is likely to suit you, based on factors including the size of the defect, your age, general health and activity levels.

What happens during the procedure?

The exact steps depend on which technique you have, but a 2-stage ACI procedure typically follows this pattern:

1. In a first, keyhole (arthroscopic) operation, your surgeon takes a small sample of healthy cartilage from your joint.
2. This sample is sent to a laboratory, where the cartilage cells are grown and multiplied over several weeks.
3. In a second, open operation, the expanded cells are implanted into the damaged area and held in place with a membrane.

With single-stage bone marrow or stem cell techniques, cells are harvested from your pelvis, concentrated in a machine during the same operation, and implanted straight into the damaged area, so only 1 operation is needed rather than 2.

What does recovery look like?

Recovery varies depending on which technique you have. Single-stage bone marrow or stem cell procedures need only one operation and hospital stay and are described as giving faster rehabilitation than a two-stage procedure.

Two-stage ACI needs two separate operations and hospital stays, several weeks apart, while your cartilage cells are grown in the laboratory in between.

What are the risks and complications?

Autograft transplantation, where healthy cartilage and bone are taken from elsewhere in your own joint, carries some specific drawbacks: taking the tissue can cause problems at the donor site itself, the amount of healthy tissue available to use is limited, and the transplanted tissue doesn't always match the mechanical properties of the area it's replacing as closely as your original cartilage did.

Two-stage procedures involve two separate operations rather than one, which means undergoing anaesthesia twice and a longer overall treatment period.