1. Definition: Articular or Hyaline cartilage covers the end of the long bones and forms the joint surfaces. It is a unique structure in that it can withstand enormous compressive forces and create a low friction surface for the joint to glide on. This complex organ is made up of cells called chondrocytes and matrix composed of proteins and sugars in a specific interwoven fabric.

2. Injury: Articular cartilage is injured when the knee joint is compressed under heavy load or when angular or shear forces are applied to the surface. The result is one of several possible lesions...softening, fissuring, fragmenting or complete removal of the cartilage covering. Symptoms include pain, swelling and subsequent loss of joint function. Adult articular cartilage does not repair itself. The reason is that the chondrocytes have little mobility and there is no blood supply to the matrix to provide healing elements. The above mentioned lesions then, are more or less permanent. Worse yet, they progress from softening to complete destruction of the joint if left untreated.

TREATMENT: If there are correctable causes of the articular cartilage problem, these must be addressed first:

a) Loss of meniscus - early stages of cartilage damage
due to loss of meniscal tissue and subsequent high
compressive loads are addressed by meniscal allograft reconstruction

b) Malalignment - abnormal knee alignment is
corrected by distal femoral or proximal tibial osteotomy. This is where a wedge of bone is surgically added to or removed from the bone adjacent to the knee to recreate a horizontal joint line and eliminate high angular stresses on the cartilage.

c) Instability - loss of the anterior cruciate ligament
(ACL) creates gliding movements in the joint and high
shear stress on the articular cartilage. This is treated with
ACL reconstruction

Once these causes are corrected, the articular cartilage lesions can be addressed. Symptomatic areas of fragmented or destroyed cartilage have traditionally been treated by abrading or puncturing the underlying bone. These techniques lead to healing with fibrocartilage which does not possess the same mechanical properties as hyaline cartilage and lasts only 10 to 12 months. Newer technologies are aimed at repairing these defects with tissue that reproduces the original hyaline cartilage surface. These innovative treatments include:

a) Autologous Chondrocyte Implantation (carticel) - if a full thickness defect in the articular cartilage (>2 cm. diameter) is found in a weight bearing area of the femoral condyle, a biopsy is obtained arthroscpically from a non-functional area of the same knee. This sample is sent to a laboratory where the cartilage cells are manipulated to replicate and produce hyaline like matrix. These "stimulated" cells are suspended in a liquid medium and then injected into the prepared defect during the second (open) surgery. The defect will subsequently fill with this new cartilage and the patients symptoms will improve as the cartilage matures over 1 year. The cost of this complex laboratory process is over $13,000.00...however this is more then justified if it saves a young, healthy, productive person from prolonged disabling knee pain, slow deterioration of the joint and ultimately a knee replacement at a relatively young age. This procedure is only recommended for patients who are between the ages of 15 and 55 and have an otherwise normal knee (alignment, meniscus, and ligament).
Dr Yacobucci has flown to Sweden to recieve special training in this technique from the surgeon who pioneered this operation. He has performed over 50 of these surgeries and is actively involved in clinical research and teaching as it pertains to this complex procedure.
b) Osteochondral Autograft Transfer (OATS) - smaller full thickness defects can be treated by transferring punch grafts of bone and cartilage from a healthy non-functional area in the knee into the prepared defect. The advantages over carticel are this can be done during one arthroscopic procedure, and the cost is significantly less. This technique is quite demanding as positioning of the grafts must be precise to create a smooth, functional articular cartilage surface. There are no age limits on patient selection and the condition of the joint need not be perfect. Full maturation of the graft is complete at about 12 weeks post-op.
c) Osteoarticular Allograft Reconstruction - a new technique of harvesting, testing and preserving bone and articular cartilage from deceased human tissue donors allows us to use these large (up to 4 cm. diameter) grafts to fill massive femoral condyle surface defects. This is the result of a patented technique developed by Cryolife corporation that perserves large numbers of viable chondrocytes in the grafted tissue. Advanced instrumentation is used to exactly duplicate the contour of the cartilage surface being repaired. A press fit secures the graft at the recipiebt site. The cost of tissue and instrumentation is$10,000.00 however, this procedure has the potential of saving a knee joint from gradual complete destruction.
Dr Yacobucci is one of only a few knee surgeons in Arizona who have succesfully carried out this procedure.

Animated video
Osteoarticular Allograft Reconstruction

Press play to view a short animation of an Opening Wedge Osteotomy

Click below to view a short clip on Autologous Chondrocyte Implantation (carticel ) Stage One and Stage Two

click play below to view a short video of
  Osteochondral Autograft Transfer (OATS)

Intra-operative photos
Osteoarticular Allograft Reconstruction

ARTICULAR CARTILAGE INJURY