A Review of Advancements in Ankle Arthroscopy

An arthroscopy is a procedure that allows a doctor to see inside a joint without major surgery. Using a small incision, the surgeon inserts a long, thin instrument with a camera on the end. Arthroscopies were often used for larger joints, like knees, but the ankle was often considered to be too small and complicated a joint for this procedure. This idea was changed in 1972 when researcher Watanabe and colleagues published the results of 28 ankle arthroscopies. Over the years since then, the procedure has been refined and is now regularly used to diagnose and treat problems of the ankle.

Endoscopic surgery uses the arthroscopic process but, using a few more very small incisions, surgeons can insert surgical instruments. By observing the inside of the joint with the camera, the surgeons perform the surgery without opening up the joint. The advantage to this type of surgery is that recovery time is shorter for the patient and the patient can return to his or her previous level of activity earlier than with traditional surgery.

Because of the anatomy of the ankle, certain problems are easier to see with arthroscopy and treat with arthroscopic surgery than others. For example, the back of the ankle is harder to access and treat because of the location. It is possible, however, by adapting the technique and positioning the patient's foot in such a way that the surgeon can access it from different angles.

Anterior arthroscopy (from the front) of the ankle should be done to look for soft tissue or bone damage, to see if there is anything loose in the ankle, and to check for any osteochondral defects, or damage to the bone or cartilage. But, it's not limited to these problems. It can also be done to help repair some types of fractures. There are some situations where an arthroscopy of the ankle shouldn't be done, though. These include if there is an infection in the ankle or if there is severe degeneration. Other situations that are recommended but may be done in certain circumstances are if there is some degeneration in the ankle with limited range of motion, if the joint spaces are narrow, vascular disease (arterial), or edema (swelling in the tissue).

Not all doctors agree that arthroscopy of the ankle is a worthwhile diagnostic tool. Some estimate that arthroscopies only help about 26 percent to 43 percent of patients. If, after arthroscopy, the diagnosis is still not certain, then further testing must be done, including x-rays. Doctors can also detect some osteochondral defects by using magnetic resonance imaging (MRIs) or computed tomography (CT) scans.

When performing arthroscopy and surgery on the ankle, there is the distraction or the dorsiflexion approach. When the patient is lying on the operating table, his or her foot can be placed in such a way that the foot is pointed away from the body, increasing the angle of the ankle. That is distraction. Or, the foot can be pushed up, so the toe is point up towards the ceiling, closer to the patient's head, reducing the angle of the ankle. This is called dorsiflexion. Using dorsiflexion to perform arthroscopic surgery often is better than distraction because distraction pulls the ankle tight, while dorsiflexion opens up and relaxes the area. However, since distraction is sometimes better, using arthroscopy, the patient's foot can easily be arranged to lie in the correct position.

As with all surgeries, arthroscopic surgery of the ankle does have its complications. These include damage to the nerves and blood vessels, infection, and a long-term chronic pain syndrome called reflex sympathetic dystrophy. How many complications occur depends on the study. There have been reports of between 9 percent to 17 percent. Up to half of complications appear to be affecting the nerves. It's suggested that using the distraction approach may be responsible for many of the complications.

With patients who have osteochondral defects, these are usually caused by a trauma (injury) to the ankle - this occurs in about 93 percent of lateral cases (along the side of the ankle) and 61 percent of medial cases (towards the middle). Patients with osteochondral defects usually have deep, off-and-on ankle pain that occurs during or after activity. There may be swelling and, at times, they may not be able to move their ankle as usual, although this isn't always the case.

To diagnose osteochondral defects, x-rays of the patient standing and bearing weight on the ankle should be taken. This may be followed by a CT scan or MRI. Once the diagnosis is made, it must be classified according to its severity. Stage I is a small compression fracture; stage II is an incomplete break; stage III is a complete break; and stage IV is a complete break with a piece of bone broken off.

Treatment varies from doctor to doctor. Usually, if the patient isn't experiencing too many symptoms or much discomfort, treatment is non-surgical at first. This is often done over six months and includes resting the ankle, applying ice, and perhaps bracing the ankle. If the ankle is causing pain, then surgery may be needed to remove the broken pieces of bone and removing unstable cartilage. This is where arthroscopy comes in. There is a 45 percent success rate for patients who are treated non-surgically while those who had surgery appear to have a success rate of around 86 percent.

Another ankle problem is called an anterior ankle impingement, which means the soft tissues in the front of the ankle have become pinched somehow. This is usually when the toes are pointed up towards the head of the body, closing the angle of the joint. This can be caused by injuring the ankle, traction, or chronic ankle instability from ankle sprains. Patients with anterior ankle impingement usually have pain around the ankle joint, swelling after activity and some limited motion in the ankle, although that's not always present. If the doctor is examining the ankle, he or she can cause pain by pressing on the bone in the front of the ankle.

Anterior ankle impingement is another condition that can be treated non-surgically or surgically. If the problem is detected early enough, treatment may be injecting into the ankle and/or providing an orthotic that lifts the heel of the foot a bit. Surgery is done arthroscopically to shave away the tissue that is trapped, reducing the pain. Studies have shown that patients who had arthroscopic surgery recovered quicker than those who had regular "open" surgeries, although the outcome was relatively similar.

If the problem is in the back of the ankle, the hindfoot, then treatment is more complicated. Since the year 2000, surgeons have used a two-sided approach to look into that part of the ankle and to do surgery. This type of surgery may be needed if there are osteochondral defects , traumas, or any other similar problem with the back of the ankle. Surgeons can also treat problems with the Achilles tendon or the calf muscle if needed.

Like with anterior ankle impingement, patients may have posterior ankle impingement, where the pain is in the hindfoot when the toes point down, opening the angle of the foot. This can be treated with arthroscopic surgery with success. In one study of 146 endoscopic hindfoot procedures on 136 patients, researchers found the surgery was successful in most patients, with only two patients experiencing minor complications.

The authors of this article concluded that there has been considerable improvement over the past 30 years in arthroscopic ankle surgery.



References: C. Niek van Dijk, MD, PhD, and Christiaan J.A. van Bergen, MD. Advancements in Ankle Arthroscopy. In Journal of the American Academy of Orthopaedic Surgeons. November 2008. Vol. 16. No. 11. Pp. 635-647.