Articular Cartilage is a cushing agent in your joints and overtime it can degenerate for a host of reasons and it has limited inherent ability for repair. There are many options for surgical treatment of knee pain that is caused by cartilage degeneration. A lot of research is being done on the different surgeries available and this article will give a brief overview of what is availble in the medical community for restoration of articular (joint) cartilage.
Cartilage imaging is common and you will most like have a specific type magnetic resonance imaging (MRI) performed on your knee. This is a noninvasive method used to visualize your knee’s cartilage status and health. The mechanical alignment of your knee (how you are built) will also influence what are available options or combinations of options for you.
There are some prescription and over-the-counter (OTC) drugs available that are being studied to examine their ability to protect cartilage and prevent or delay cartilage degeneration. A couple common OTC drugs are glucosamine and chondroitin sulfate. Studies on the drugs out there have been mixed in reporting benefit, so there is not a clear benefit of taking one of these medications yet. Prescription medications and OTCs effectiveness also depend on your mechanical alignment. If there is overloading on one side of your knee it is not likely that a medication will be of significant help alone.
Bone Marrow Stimulation and Microfracture
These techniques encourage the formation of new cartilage cells by stimulating underlying bone. Very simply put, in these procedures little divots are made in the bone and they bleed stimulating new cartilage growth. A systematic review (summary) of studies with greater than 3000 patients found that knee function was improved two years after microfracture. After two years, function declined but was still above pre-operative levels. Some shortcomings of microfracture are: unpredictable repair cartilage volume and higher failure rates for cell transplantation surgery (this well be described later). At the present time procedures that stimulate bone marrow are best for a first choice if the defect is isolated to the femoral condyle and smaller than 2.5cm^2.
These types of surgeries attempt to repair cartilage in the joint by injecting stem cells or your own chondrocytes (a cell found in cartilage). Implanting chondrocytes requires two separate surgeries with a period of growing the cells in-between. This can create a high cost and a substantial amount of time to finish the procedure. One study found superior results with chondrocyte implantation vs. microfracture when surgery was performed within three years of symptom onset. A study of 100 patients with 10-year follow up reported autologous chondrocyte implantation for lesions greater than 2cm^2 had a low failure rate (17 per cent). There is limited information on success rates with stem cell implantation but clinical trials to validate the technique are underway.
Chondral and Osteochondral Grafts
Cartilage autografts (your own body tissue) and cartilage allografts (donor tissue) have demonstrated growth of new tissue at the cartilage lesions. Operative procedures are fairly straightforward and require just one operation. Osteochondral (bone/cartilage) plugs have properties of both tissues so they provide a complete unit of graft tissue. Research has shown them to be a good option for lesions less than 3cm^2.
Non-weight bearing and partial weight bearing are used for a time during rehabilitation times frames range from eight to twelve weeks. Rehabilitation programs will depend on surgery, health status, cartilage lesion size, structural joint factors and age.
Restoration of Mechanical Environment and Summary.
If there is a structural deformity in the knee a surgery may need to be performed to improve success of of cartiage repair procedure.Techniques are used to cut away bone to make an equal loading surface. Cartilage surgery must focus on restoration of joint mechanics, address the defect-specific variables (location, size, numbers, bone health). Patient characteristics are also considered such as age, body mass, symptoms, lifestyle and surgical history. These procedures are fairly new and the quality of research is limited.