Autologous Cartilage Implantation (ACI AND MACI)

Indication and Procedure Description

This procedure is indicated for those patients who have an isolated full thickness articular cartilage defect in the knee, which is causing symptoms such as pain and clicking. This injury is generally from an acute injury, but can also occur over time, due to repeated injuries. The knee is generally swollen and pain is located over the site of the cartilage injury. It is not a suitable procedure for established osteoarthritis as yet.

The procedure involves taking a biopsy (sample) of the healthy cartilage from the knee through an arthroscopy (keyhole surgery). The size of the defect will also be assessed at this time. The cartilage biopsy is processed in a laboratory where the cartilage cells will be cultivated in a matrix and this takes approximately four to six weeks. Once the matrix or cartilage is ready, it will then be re-implanted. The re-implantation occurs through an arthrotomy where the joint is opened through a small incision to allow accurate placement of the cartilage graft.

Pre-operative Preparation

After a thorough clinical assessment of the joint, the patient will generally have plain X-rays and an MRI scan of the knee to help accurately assess the location and size of the cartilage defect. At times, the patient may have previously had an arthroscopy. A range of motion brace will be organized prior to the surgery and this will restrict the joint movement and protect the cartilage graft.

Hospital Stay

The initial arthroscopy for the biopsy is preformed as a day surgery procedure. The implantation surgery requires a hospital stay of two to three days. The procedure is usually performed under a general anaesthetic and supplemented with a femoral nerve block to help the post-operative pain.

Post-operative Care

Knee brace

A knee brace will be required for a period of up to three months, depending on the exact location and size of the cartilage defect. The range of motion that will be allowed in the knee brace will also be determined by the exact location and size of the cartilage defect. Generally the patient’s weight bearing is restricted for the first six weeks.

Physiotherapy

This will be commenced immediately and range of motion will also be determined by the exact size and location of the cartilage defect. Initial physiotherapy is concentrated on static quadriceps and hamstring exercises to maintain muscle bulk.

The post-operative rehabilitation regime will be coordinated through your doctor and physiotherapist.

The patient will be seen at two weeks, six weeks, three months and one year post-operatively.

Return to sport is generally at one year. Sport specific exercises however can be commenced at six months. There will be no jogging or running unsupervised until six months. Some sports, such as swimming and cycling, can be commenced at six months; however no contact or high impact sport can be played for one year.

Return to Work

Sedentary work

This can be commenced from two to six weeks after surgery.

Non-sedentary work

This can be commenced from six weeks to three months, depending on the exact nature of the employment.