The ankle joint is comprised of the ends of the tibia and fibula articulating with the talus bone. Osteochondral lesions are injuries that occur to the cartilage (chondral) and the underlying supporting bone (osteo). The cartilage is the smooth covering of the bone that allows the joint to move pain free. It is a remarkable substance that provides both gliding and support to the joint. When the osteochondral lesion is not just one or two areas, but multiple areas on both sides of the joint, then it is considered arthritis . Osteochondral lesions are also referred to as osteochondritis dessicans and osteochondral fractures. This discussion focuses on the talus since this is the most common location for osteochondral lesion in the ankle.
Osteochondral lesions may be related to a traumatic episode, but there may be no defining episode the patient can recall. This may imply that it is an old injury that became symptomatic. The patient may have a history of frequent sprains and instability. The symptoms are usually mechanical in nature and described as a clicking, catching sharp pain that occurs with activity. The joint may have swelling (effusion) and decreased range of motion. X-rays may show the lesion if it is larger or has a significant bony component. A MRI is obtained to show the size of the cartilage injury and the degree of bone involvement. A MRI will also show if there is any tearing of the ligaments or tendons.
Initial treatment can include activity modification, over-the-counter oral anti-inflammatories, bracing and physical therapy. A cortisone injection can be considered, however this should be only once or twice since multiple cortisone injections can cause further chondral damage. Hyaluronic acid injections, which are commonly used in the knee, has not been beneficial for the ankle in my opinion. Stem cells such as PRP or BMAC can be considered. PRP can be performed in the office without anesthesia whereas BMAC is performed under anesthesia in the operating room and usually conjunction with surgical procedure to enhance healing.
Cartilage surgery is considered if a patient fails nonoperative treatment. This is an evolving field and there are many options. Most procedures are performed arthroscopically. The most common procedure is an arthroscopy to debride or remove the damaged cartilage and bone. This can be likened to a pothole in a road. The bony lesion is then drilled or microfractured to stimulate blood flow and healing. This “pothole” can be left to heal with scar or fibrocartilage/bone or filled with autograph (tissue from the patient) or allograft (tissue from a cadaver). Synthetic substitutes or matrices can also have a role in treatment. At the end the surgery, BMAC can be injected into the joint. The most common non-arthroscopic or open procedure is OATS. This requires an osteotomy or cutting the tibia or fibula leg bones in order to gain access to the cartilage in a perpendicular fashion. OATS an abbreviation for Osteochodral Autograft or Allograft Transplantation System. The system harvests a plug of bone and cartilage which is used to fill this “pothole”. The procedure involves fixing the osteotomy with screws. This treatment is usually reserved for very large lesions or those that failed more minor procedures. The determination of the exact procedure depends on the size and depth of lesion. Cartilage surgery is an evolving field and there are many options that can be considered. There is no consensus on which treatment is superior. As a result, the above paragraph discusses the surgical options in generalities. These procedures are done as an outpatient under general or regional anesthesia. The exact recovery protocol depends on the type of procedure.