about_aci

ACI, Autologous Chondrocyte Implantation or Carticel, has been worldwide for
over fifteen years. It was originally conceived and tested by Lars Peterson, MD in Sweden and it is through much of his data that we have found the impressive
results of ACI. He found that chondrocytes, cartilage cells, could be grown in a special culture medium and rapidly increase their numbers.

He was able to control the cell growth so that they become Hyaline Cartilage. Hyaline Cartilage is very special. It covers the bone ends of all the joints. Joint surface cartilage, Hyaline Cartilage, does not repair itself; rather once damaged it can deteriorate through a complicated cascade of mechanical and chemical influences resulting in Degenerative Osteoarthritis.

The unique advantage of ACI is that we can now, for the first time, repair injury to the joint surface back to nearly the original Hyaline Cartilage. A few thousand cells are harvested from the non-weight bearing area of the joint. They are then grown under strict conditions and sterile procedures. Then, in a second operative procedure, a piece of the lining of the bone or another allograph biologic material is transposed to cover the defect. The cells are then implanted under this lid and into the closed space thus created. (See ACI procedure)

The results of the cell implant procedure can be impressive. In some cases, patients with chronic knee pain (as long as 20 years) became pain free after the implant operative procedure. In some patients a hole in the femoral condyle (thigh side of the knee joint) which would have almost assuredly lead to osteoarthritis, was treated leading to no symptoms. ACI may well save the patient as much as 20 to 25 years without significant problems.

Statistics show that for the isolated lesion, there is a 92% success rate, for multiple lesions within the same knee compartment there is an 85% success rate. For people with kneecap problems there is an 85-87% success rate if done with an osteotomy procedure. These are important numbers because here-to-fore, surgeons had no good options for these significant lesions. Beyond these impressive statistics, the cartilage grown and therefore the procedure has been shown to be very durable. Dr. Peterson found the results at two years equal the results at 11 years. That means that the results do not deteriorate with time and therefore these procedures can offer long-term benefits for selected patients.

Charts adapted from Peterson , et al.

Your results may vary, but ACI offers a chance to save further knee deterioration in selected cases. For improved results some cases require corrective bony realignments called osteotomies. That means in some patients, the tibia may need to be cut to realign forces on the knee joint or the patella attachment may need to be elevated to take pressure off the kneecap. Stability is also very important. If the anterior cruciate ligament has been torn, it needs to be reconstructed to stabilize the knee prior to or in concurrence with ACI. The result is that the implant operation can take from 2 hours for a simple singular lesion to as much as 4-6 hours for complicated lesions with a bony osteotomy.

After the operation, you will need extensive rehabilitation that is particular to your lesion or lesions and your operation. Often there will be some time of non-weight bearing and use of crutches. There will usually be some limited range of motion, ROM, as controlled by a hinged brace. Most surgeons use a CPM, continuous passive motion, machine to keep the knee limber without putting pressure across the joint. Slowly and progressively your ROM will be increased. Your strength will follow. Interestingly, many patients start to feel so good that they want to move to higher levels of activity too soon. Unfortunately, in some cases the surgeon has to hold the patient back. Regardless of how the patient feels, physiology just takes some time. The graft or implant will not mature to allow high compression forces until about 9 months. If the patient is too active too soon, the graft can seriously be compromised or fail. Therefore, most patients will not be able to run until about 9 to 12 months. However, you will be allowed to be full weight bearing at about 6-8 weeks of your surgery. Lastly the grafts cartilage regenerative process will be complete at about 18 months. It is at this time that the joint has been restored.

ACI, Carticel, has been shown to be a viable option for selected lesions. Though the implant procedure is inconvenient because of the time obligation involved, the results can be very gratifying.