Cartilage is the smooth, gliding surface that lines each of our joints. This tissue allows joints to move freely and gives us our ability to walk, run, jump and play sports.  Arthritis is the condition in which the cartilage of the joint wears out. In the ankle, arthritis typically occurs after injury such as ankle fractures. Inflammatory conditions such as gout or Rheumatoid arthritis can also lead to arthritis.  

There are also injuries that can occur to the cartilage in the ankle joint.  This can occur after an ankle sprains/fractures and are common problems in young and middle-aged athletes. During these injuries, the lining cartilage of the joint is bruised or sheared off during the twisting injury.  The condition has been called an osteochondral lesion of the Talus (OLT) or osteochondral defect of the Talus (OCD). A corresponding cartilage can occur at the end of the tibia although this is less common than cartilage injury of the talus.

Patients with a talar dome OLT will complain of ankle pain, stiffness, swelling and possibly feelings of “catching” in their ankle. Physical examination demonstrates pain with motion of the ankle, swelling, and at times, instability of the ankle. X-rays are obtained to make sure patients do not have fractures or arthritis of the ankle. Occasionally, a small avulsion of bone that the cartilage is attached to, can be seen on the radiographs. An MRI is the best test to reveal an OLT and this test will also assess other areas of the ankle that can be causing pain (such as tendonitis, stress fractures etc.). 

A cartilage injury does not necessarily mean surgery. Previous studies have shown that approximately 45% of patients can actually avoid surgery (Tol et al, 2000). Non-surgical treatment includes immobilization in a walking boot/cast, physical therapy, and NSAIDs. If patients have symptoms for more than 6 weeks to 3 months, surgery is recommended. 

Even with all of the advances in medicine over the years, there is no perfect treatment for cartilage defects. We do not have the ability to fabricate cartilage that has the same make-up and structure of native cartilage. There are different surgical options available that have been shown to recreate tissue that is close in form/structure to native cartilage and will allow patients to be pain free and return to sports. These procedures include: microfracture, mosaicplasty, allograft reconstruction, autologous cartilage transplantation, and juvenile cartilage transplantation. 

The traditional treatment for cartilage injury or defects is microfracture. This is a procedure that can be done using the arthroscope and small incisions. An incision is made so that a small camera may be placed into the ankle joint. A second incision is then made for placement of instruments to allow removal of all loose cartilage in the area of the cartilage defect. Once all loose cartilage is removed, there will be an area of exposed bone. Multiple perforations or drill holes are then made in the bone to allow bleeding and ultimate formation of fibrocartilage or scar cartilage. This tissue fills in the gap with time. The tissue is not as resilient as our normal cartilage but seems to work well. Patients are allowed to move their ankle shortly after surgery but are kept non-weight bearing for a few weeks. Return to sports occurs approximately 3 months following surgery. This technique has been found to be best for smaller cartilage defects (less than 1.5 cm in diameter) and is helpful in approximately 79-90% of patients (Ferkel, 2008). 

Recently there have been different procedures designed to supplement microfracture by adding growth factors or allograft cartilage tissue to the defect after the area has been debrided and microfracture has been performed.  One such material is BioCartilage from the Arthrex company.

There are certain cartilage defects in the talus that are larger in size and are not appropriate for microfracture.  There are also patients who have undergone a microfracture procedure and are still having pain or feelings of catching. There are other options for these patients.  One such procedure is a mosaicplasty or OATS procedure. This surgery involves taking a plug of cartilage and bone from another area of the body and placing it in the area of the cartilage defect. Most often the cartilage and bone plug is taken from the knee (in an area of the joint that can function well without cartilage). Using special instruments, the cylindrical plug is then placed into the talus which brings healthy bone and cartilage to resurface the joint. This is a larger procedure that often requires larger incisions and, at times, an osteotomy (cutting the bone of the tibia) to allow placement of the cartilage plug. Mosaicplasty has good results in approximately 90% of patients (Imhoff, 2011) and is best for patients with moderate size defects of the talus cartilage. 

A further option is use of allograft juvenile cartilage to fill the cartilage gap.  The cartilage is taken from young people who have passed away and whose family has consented to have their tissue donated. This tissue is tested to make sure there is no contamination or disease and then packaged for use in the OR. At the time of surgery, the juvenile cartilage is placed into the cartilage defect and secured with fibrin glue. It is felt that the young age of the donated tissue allows a more robust filling in and repair of the cartilage defect.  This product is called DeNovo and is produced by Zimmer.

Autologous cartilage transplantation is a further option.  With this procedure, a piece of cartilage is taken from the ankle during an arthroscopy and sent to a company called Genzyme. The company will then harvest the chondrocytes (cartilage cells) from the sample and will grow approximately 12 million new cartilage cells. These cells are sent back implanted on a membrane. Patients undergo a second surgery in which the grown cartilage cells in the membrane are placed in the defect.  They are typically secured with fibrin glue. With time, the implanted cartilage cells allow new cartilage to grow and fill in the defect. This procedure has been done for the past 20 years and is helpful for larger defects of the talus.

There are certain patients who have an OLT in which a large percentage of the talus cartilage is damaged. These patients are often managed with use of an allograft talus. In this procedure, an allograft talus, which is a talus that comes from a person who has passed away and has donated their organs/bones to help others, is obtained from a tissue bank. Prior to sending the allograft talus to the operating room, the tissue is tested for disease to ensure that the tissue/bone is safe for use. During the surgery, special instruments are used to take part of the allograft talus and secure it to the patient’s own talus to resurface the joint surface. This is not a common surgery but can work well for patients with large to massive defects of the talus.