ACHILLES TENDON INJURY

The achilles tendon is one of the strongest tendons in the body- but it’s not just one tendon; it’s a combination of two. Generally when you think of a muscle in the body, at one end of it is a tendon that will attach to a bone that needs to be moved. One muscle for one tendon. The Achilles tendon needs to have power at all times since it serves to keep us walking properly which takes a lot of force. The calf muscles include two, the gastrocnemius muscle and the soleus muscle. Both of these muscles are responsible for specific duties while walking, and even though they do the same basic operation they can work independently of each other. In this picture you can see the gastroc in red and underneath it is the soleus in green. There is one HUGE difference. You can see the red gastroc goes up higher than the green soleus. Actually the gastric goes from the femur just above the knee to the heel bone (calcaneus). This is very different than 99% of the muscles i the body. It spans across two joints, others span just one joint. So since the gastroc spans two joints, when it contracts it can effect two joint motions. When is contracts it can bend the knee (flex) and flex the ankle down (plantarflex).

TENDONITIS VS TENDINOSIS VS TENOSYNOVITIS

These are common terms you hear when there is irritation of a tendon but not a tear. Lets go through these terms so you can understand exactly what’s they mean. First of all : Tenosynovitis. IT can not exist in the achilles tendon so if that is your diagnosis it is incorrect. Tenosynovitis is irritation in a thin tissue called the synovium (hence -synovitis) but an achilles tendon doesn’t have this synovium. The only tendon that do have this layer over the tendon are tendons that curve around a joint and need a special lubrication. The achilles has no need for this .

Next is the term Tendonitis - this is usually an acute injury, a sprain or a pull that gets the achilles tendon irritated. You can experience painful motion, tenderness, swelling in the tendon. With conservative treatment, rest , ice ,elevation, anti-inflammatory medication this should generally resolve.

On the other hand if a tendonitis is not treated properly or at all a chronic inflammation process will degenerate the tendon - this is called achilles tendinosis. This is a more significant injury where the collagen structure of the inside of the tendon will degrade leading to pain, stiffness, weakness, limit to function. When there is tendinosis the structure of the tendon can get so weak that a tear can happen. This often happens to athletes who ‘ play through‘ an achilles injury and then develop tendinitis and then a tear.

ACHILLES TENDON TEAR

The achilles tendon has an anatomical weakness most other tendons do not have. Blood flow to the tendon comes from two different locations, one blood vessel to the bottom of the tendon, and one different blood vessel to the top of the tendon. These two blood supplies come together in a “no mans land”. In medicine it’s called the ‘watershed area’ - a place where there is very little blood flow altogether right inside the tendon. This area is a few inches above the heel bone and most achilles tears often happen in that area!!

A simple test : Thompson Test

As this picture shows, a patient is laying on their stomach. the doctor will squeeze the calf firmly. If the achilles tendon is intact the foot will plantar flex. IF there is no achilles tendon because of a complete tear then the foot will not move at all. Its not a perfect test but works well in most cases.

HOW THE TEAR HAPPENS

The term doctors use for “how it happens” is ‘mechanism of action’. This is important because in some cases it also reveals to us the best way to treat an injury. Many times there is a stretching of the tendon and at the same time there is a contracture of the calf muscle. This literally pulls the tendon apart. A healthy tendon is very strong so usually a torn tendon has something happening beforehand- tendonitis or tendinosis. There are two kinds of tears, if the bone is weaker than the tendon, the attachment of the tendon to the bone may tear off with a piece of bone. If the tendon is weaker then the tendon will tear and that most often happens in the farthest most 6 inches of the tendon in back of the ankle. Many times the tear is partial; not the whole tendon tears. It really just depends on the previous chronic damage in the and the exact mechanism of action.

HOW WE REPAIR THE TENDON TEAR

The approach to repair really depends on the mechanism of action and exactly to kind of injury. But overall the procedures can be divided into open procedures where a large incision is made or a percutaneus repair (small incisions). One is not neessarly better than the other even though we do always prefer smaller incisions. Even in the open repair the incision is only made as large as necessary. When the percutaneus approach is used usually a special device is used to pull the tendon together. You can see the video here that illustrates the use of one of these devices.

The open repair is very useful because the entire tendon can be inspected and adjunct procedures can be performed as needed. These other procedures are ones that are used to reinforce the repair of the Achilles Tendon. For example we sometimes take healthy tendons that live right next to the achilles and incorporate them into the repair or we perform certain lengthening procedures onto the achilles tendon to get them to the proper length allowing us to balance the ankle properly. In some cases surgeons will use fake tissue grafts to stenghten the repair. We prefer never to do this since we dont want to place any foreign material into the body unless we have no other options. Fortunately there are many options for there repairs.

WORK IN PROGRESS!!!!!!!!!