More than 70% of spontaneous ruptures occur during sports, mostly during ball games such as badminton, basketball, soccer, tennis or track and field sports such as running. Disease Description The Achilles tendon is the thickest and strongest tendon in the body. The Achilles tendon is about 15 cm long and is formed by the fusion of the tendons of the triceps muscle of the lower leg (flounder muscle, inner and outer head of the gastrocnemius muscle). During this process, there is a 90° twist of the tendon fibers of the Achilles tendon. The main function of the Achilles tendon is to flex the calf and plantarflex the ankle, and it is the most important anatomical structure for the transmission of force from the calf muscles to the foot. The ability to stand upright, stand still, run and jump is all dependent on it. If the Achilles tendon is ruptured unilaterally, limping will occur, and if both Achilles tendons are ruptured, walking will be impossible. The ancient punishment of “severing the hamstring” means that the prisoner’s Achilles tendon is severed bilaterally, causing him to lose the ability to walk. Causes Spontaneous rupture occurs most often in athletic people between the ages of 30 and 50, but also in non-athletic people over 50 and in women. The incidence can be 8.3/100,000 people/year. The rupture occurs mainly in men, with a male to female ratio between 2:1 and 18:1. If an Achilles tendon rupture has occurred in one limb, the chances of having the other Achilles tendon rupture can increase more than 18 times. The causes of spontaneous rupture may be multiple, including congenital collagen abnormalities, infectious diseases, rheumatoid immune diseases, endocrine diseases, neurological abnormalities, abnormal hormone levels, decreased blood supply to the Achilles tendon with age, degeneration of the Achilles tendon due to excessive exercise, use of steroid hormones or fluoroquinolones such as haloperidol, high temperatures, and tendon calcification, all of which may lead to spontaneous rupture of the Achilles tendon. Clinical manifestations More than 70% of spontaneous ruptures occur during sports. Patients tend to play ball games such as badminton, basketball, soccer, tennis or track and field sports such as running. Patients themselves may feel that they have been hit or kicked in the heel, which is actually their own sensation when the Achilles tendon is ruptured and not a real trauma as such. The patient basically does not experience significant pain, but immediately develops a limp and inability to lift the heel on one foot, and later gradually develops swelling and bruising over the heel. Because the post-injury swelling masks the depression caused by the rupture of the Achilles tendon, the presence of the plantar tendon and the long flexor tendon of the mother foot allows partial compensation of the plantar flexor strength of the ankle joint so that walking is still possible, and there is no fracture on x-ray, the patient or even some physicians may think it is a simple soft tissue injury and miss the diagnosis, thus delaying treatment. This is not uncommon, and statistically, up to 25% of Achilles tendon ruptures can be missed at the initial visit. A visit to a specialist sports medicine clinic is essential to avoid similar misdiagnosis. Diagnostic Differentiation Common imaging tests include ultrasound and MRI. Ultrasound is currently the most accurate diagnostic method for diagnosing Achilles tendon rupture. By observing the continuity of the Achilles tendon fibers, ultrasound can determine not only whether the Achilles tendon is ruptured, but also the location of the rupture, which can help determine the treatment plan. Disease Diagnosis The diagnosis of Achilles tendon rupture can generally be determined clinically through history and clinical physical examination. On physical examination, the patient can palpate a depression in the area where the Achilles tendon is located due to the loss of integrity of the Achilles tendon. In addition, the patient may be asked to stand on one foot or squeeze the calf muscles in the flexed knee position to observe the strength of the ankle joint movement. For patients who are unsure, imaging may be performed to assist in the diagnosis. Disease treatment Depending on the timing of the Achilles tendon rupture, it can be classified as acute rupture, subacute rupture and old rupture. In general, an Achilles tendon rupture that is less than 3 weeks after the injury is an acute rupture. An Achilles tendon rupture that is 3-4 weeks after the injury is a subacute rupture. And if the Achilles tendon is not treated 4-6 weeks after the rupture, it can be called an old Achilles tendon rupture (Figure 1). Re-tears after treatment of the initial Achilles tendon rupture (including conservative or surgical) are also generally considered old Achilles tendon ruptures. The treatment of these types of Achilles tendon ruptures varies considerably. We will describe them separately. Acute Achilles tendon rupture Acute Achilles tendon rupture can be treated conservatively or surgically. Conservative treatment Conservative treatment is mainly to keep the ankle joint in extreme plantarflexion for 4 weeks in a cast, so that the ruptured end of the Achilles tendon can contact and heal on its own. During this period, it is necessary to strictly walk with crutches, and the affected limb should never bear weight or have calf muscle contraction, and then be fixed with a brace for 4 weeks to ensure adequate healing. Surgical treatment generally refers to suturing both sides of the Achilles tendon and fixing the Achilles tendon with sutures to achieve full and firm contact, and then fixing the Achilles tendon with a cast for 4-6 weeks to achieve full healing of the Achilles tendon. There are advantages and disadvantages of conservative and surgical treatment. The advantage of conservative treatment is that surgery can be avoided. However, complete prohibition of calf muscle contraction during cast immobilization is difficult to achieve. Patients may inadvertently contract their muscles when walking with crutches or even when standing up, resulting in inadequate healing of the Achilles tendon, which may affect the outcome. The chance of non-healing and re-rupture of the Achilles tendon after conservative treatment is very high, up to 12.6%, while the chance of re-rupture of the Achilles tendon after surgical treatment is only about 2%. Once the Achilles tendon does not heal or re-tears, it will be treated as an old tear and the treatment will be far less effective than an acute tear and the complications of surgery will increase exponentially. The advantage of surgical treatment is that the efficacy of the treatment is definite and normal walking and moderate exercise can be resumed after surgery. However, due to the poor local blood supply to the Achilles tendon, the chance of non-healing or delayed healing and local infection after surgery can be as high as 7.5%, and some patients can even suffer from Achilles tendon infection and necrosis. Second, surgical treatment Although surgical complications may exist with surgical treatment, if the patient cannot accept the quality of life with subsequent claudication, considering the high chance of non-healing and re-rupture of the Achilles tendon after conservative treatment, as well as the resulting increased surgical difficulty and complications, the prevailing view is to perform surgical suturing as early as possible. The best time to operate on an acute Achilles tendon rupture is within 6 hours of the injury, but this is rare in clinical practice. Later, as time increases, the ruptured portion of the Achilles tendon will retract and degenerate, eventually preventing direct suturing. In general, direct suturing of acute tears of the Achilles tendon within 3 weeks of injury is possible. For patients more than 3 weeks post-injury, direct suturing may not be possible due to degeneration and retraction of the Achilles tendon, and indirect suturing by reversal of the tendon or other surgical approaches may be required. The chance of postoperative wound non-union and postoperative functional recovery in this group of patients is not as high as in the former group. Conservative treatment The treatment of old Achilles tendon rupture is either conservative or surgical. For elderly patients, if they can accept the life of limping, they can be treated conservatively and wear brace to improve the function. However, for younger patients, who mostly cannot accept the result of lifelong claudication, surgical treatment can be used. There are many kinds of surgical treatments for old Achilles tendon rupture, which can be broadly divided into two categories: 1, using the Achilles tendon rupture tissue: turning the calf muscle (proximal end of Achilles tendon rupture) to make up for the ruptured end, or splitting and pulling down the muscle so that the ruptured end can be anastomosed (V-Y repair). But this kind of method is very traumatic, the surgery is difficult, the operation time is prolonged, the complications are also increased accordingly, and the distance that can be compensated is short, the tissue available for repairing the defect is thin and little, in addition, this kind of method will damage the normal tissue of the proximal end, which may lead to the proximal Achilles tendon tearing again. 2.Tendon grafting: This type of method uses normal tendon tissue from the surrounding or other locations to replace the defect between the two ends of the Achilles tendon, which can minimize the difficulty, operation time and complications of the surgery. The selection of the graft can be based on the length of the defect, ensuring that there is sufficient tendon tissue in the area of the defect. The literature shows that the clinical efficacy of this type of approach is superior to that of the type 1 approach. In this category, the tendon grafts selected can be divided into 4 categories: 1) tendons adjacent to the Achilles tendon: 1) the long flexor tendon of the mother foot; and 2) the short peroneal tendon. These tendons are selected for their good histocompatibility and fast healing. However, additional wounds are required during tendon retrieval, adding additional neurovascular injury. In addition, the former will result in movement of the ankle and big toe, and although the lack of movement is small, function can be significantly limited; the latter will result in decreased muscle strength and compromised blood supply to the Achilles tendon during high-speed movements. 2) Free autogenous tendon: mainly the semitendinosus tendon or thin femoral tendon. These two tendons are widely used in ACL reconstruction and can provide enough tendon tissue for a very safe tendon retrieval procedure. However, additional incisions are required during tendon retrieval, which may damage the saphenous nerve. In the postoperative period it can lead to a decrease in internal rotation and flexion of the knee muscles.