to my physician colleagues

The concept of preserving the joint is a multi-faceted thought. It is not just addressing the articular cartilage though that is a large part of it. It is evaluating causative factors and addressing predisposing issues and where they can be addresses aggressively approaching and treating those factors. The question then becomes, if we can protect the joint, can we influence or decrease the relative chance of future arthritic changes? Then, the next step is how to repair or restore the joint to preserve it following gross injury or repetitive microtrauma.

The examples of these are familiar to us all, but perhaps we should review them.

  • If a meniscus is torn in a young patient, try to repair it. It helps to preserve the integrity of the joint.
  • If an ACL is torn in an active patient, repair it, it will help decrease shear forces within the joint and tends to preserve the meniscal cartilage.
  • If the joint is out of align, an osteotomy is often done to re-balance the joint and these are becoming more common in younger age groups.

Why, then are we reluctant to aggressively address articular cartilage problems? The natural history of these lesions is an enlargement and progressive dysfunction. They act as “potholes” growing larger with time and stress.

The concept of early intervention is important. As surgeons we should re-think old ideas of when to intervene. Limited lesions can be treated more effectively earlier. Effusions and pain and signs of dysfunction, we should treat them. Arthroscopy can be used as a staging procedure to define secondary operative options if needed.

Treatment of cartilage lesions is a continuum of care. There are many options which can be determined by size and location of lesion, size and activity of patient, age of patient, expectations of patient, isolated vs. multiple lesions, general health of the joint, and as much as anything else is surgeon preference. Many of these options overlap and therefore for any given lesion there may be several options. The various options of simple debridement, microfracture, allographic and autographic osteochondral systems, and ACI are not mutually exclusive, but rather are options that should be considered in the algorythym of treatment for any given lesion. I use all these options and many parameters are evaluated.

adapted from Brian Cole, MD

 

Some indications to consider:

  1. Simple Debridement and Chondroplasty
    1. Can be used for any lesion in the knee in any location
    2. It is a limited fix and relatively poor longevity
  2. Microfracture or Marrow stimulating techniques
    1. Size of lesion is a limited factor – some argue lesions smaller than 2 x 2 cm are appropriate; some argue smaller – in the JPC we use 1 x 1.5 cm as our criteria.
    2. Most will argue that the lesion should be well shouldered and contained.
    3. Most will do the procedure on the condyles or trochlea – not on the patella and only occasionally on the tibia
    4. Microfracture generally creates a fibrocartilage within the lesion which has a limited durability of approximately 3-5 years.
  3. Autographic osteochondral graphs (OATS)
    1. Transfers articular cartilage to the injured area
    2. Autographic graphs take tissue form one part of the joint in order to repair another part of the joint
    3. Multiple graph plugs can be taken but that as well sacrifices from another part of the joint
      1. Mosaicplasty has been popularized by some to be used for larger lesions
      2. However many will stop at no more than two and occasionally three plugs
    4. This technique is good for lesions on the condyles and trochlea. It is not as easy to use on the tibial plateau and does not do well for the patella.
    5. It seems to have good longevity
  4. Allographic osteochondral graphs
    1. Transfers articular cartilage to the injured area
    2. Uses donor tissue as graph source, so there is no sacrifice of tissue from the joint
      1. Relative chance of disease transmission has been addressed in recent years and does not currently seem to be a realistic concern
    3. This technique is good for lesions on the condyles and trochlea. It is not as easy to use on the tibial plateau and does not do well for the patella
    4. It seems to have good longevity
      1. The cartilage seems to have good longevity whereas the limiting factor seems to be incorporation of the bone part. Therefore, many are decreasing the size of bone part of the osteochondral graph to as little as 5 mm deep into the subchondral bone.
  5. Autologous Chondrocyte Implantation
    1. This technique can be use anywhere in the knee joint – condyles, trochlea and patellas do equally as well. The procedure can also be done for the tibial plateau though the results are not as well established.
    2. Any size lesion can be done. In the Joint Preservation Center, multiple lesions with a combined size of greater than 28 sq cm have been done with good results.
    3. Longevity seems to be very good.
      1. The critical time seems to be the first 2 years. If the patient can get to two years following implant, their results tend to plateau and continue at that level. Overall approximately 76-80% of all patients do well into their 2nd year. Isolated condylar or trochear patients tend to be better showing as much as a 92% success rate at 2 years.
      2. Longevity studies have been done demonstrating this preservation of function. One such study published shows the comparison 2 and ten year studies. (AJSM Vol 30, No.1, 2002), The 5-11 year results were equal to if not better than the two year results, indicating good long term stability of the results.


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