Achilles tendon repair surgery is commonly performed for one of two different reasons. The first reason is to repair a tendon that has become damaged due to chronic irritation and degeneration and is not responding to nonoperative care, often seen when a heel spur or tendon calcification is present. This damage can take the shape of partial tendon tearing, tendon weakening, and tendon splitting. The tendon can also thicken and become fibrotic (scar-like). The second reason an Achilles tendon is repaired is an acute rupture of the tendon. This is seen during sports injuries, as a result of chronic tendon degeneration, and following the administration of certain medications, including a specific class of antibiotics called floroquinolones.
Achilles tendon repair surgery is performed with one lying on their stomach, although some cases can be performed with one on their back, tilted to one side. An incision is made on the back of the heel, along one side of the tendon or the other. Once the tendon is exposed, it's delicate covering, called the paratenon, is gently moved to either side of the tendon, where it will be used to cover the tendon after the surgery is done (if it too has not been damaged during the injury or degeneration).
If the tendon is intact and is damaged due to chronic irritation from a bone spur, it may be stripped from the heel bone to access the bone spur underneath, which is shaved and smoothed to reduce irritation on the tendon. Otherwise, it is left intact. Any damaged or nonviable tendon tissue is removed, and the tendon is then reattached back on the heel bone using a tendon anchor if it was removed. The tendon is then inspected for any tears or weak areas, which are either repaired with suture or reinforced with tendon grafts or other tissue designed to strengthen and protect the tendon material. A relatively newer technique involves using a handheld wand to deliver penetrating radiofrequency waves into the tendon after it is repaired and before graft materials are added to stimulate healing. This technique has generally been quite successful. Once the tendon is repaired and strengthened, the outer covering is repaired, and the skin closed with suture. Recovery often involves four weeks in a below-knee cast and crutches, especially if the tendon had to be removed from the heel bone, as it needs absolute protection from motion so it can reattach properly. This is usually followed by four weeks in a walking boot, and then four weeks of rehabilitated walking. Some cases can advance to walking far faster, especially if there is no spur and the tendon damage was mild.
If the tendon damage was due to an acute tendon rupture, the ruptured end of the tendon must be found and stitched back together so that they heal as one. Unfortunately, this is not always easy to do. As tendon ruptures, the end still connected to the muscle can retract back into the calf, making reattachment of the ends difficult. This is especially true if several weeks or months have passed since the time of rupture and the time of surgery. During that time period, the tendon end becomes scar-like, and can no longer be easily stretched to meet the other ruptured end still attached to the heel bone. For this reason, it is best to repair a ruptured Achilles tendon as quickly as possible. If a delay is necessary, or if the rupture was not diagnosed for a while, several additional techniques may be necessary to complete the repair. These may include lengthening the tendon, stretching the calf muscle fibers to gain length, or using various grafting techniques to fill the gap created by the retracted tendon end. Recovery involves four weeks or more of immobilization in a leg cast and is usually followed by several more weeks of protective walking and rehabilitation.