What Is the Talus?

Talus jùg [astragalus]: It forms the ankle joint with the distal end of the tibia and the lower end of the fibula, becoming the body's largest weight-bearing joint. The talus is one of the proximal bones of the sacrum of higher vertebrates, and is considered to be equivalent to the fusion of the tibial bone and the intermediate medium of many lower vertebrates [talus]. It bears the weight of the human body and is related to the ankle and calf related nodes Of bone. Is a short bone, located between the tibia, fibula and calcaneus, divided into three parts of the head and neck body.

Talus jùg [astragalus]: It forms the ankle joint with the distal end of the tibia and the lower end of the fibula, becoming the body's largest weight-bearing joint. The talus is one of the proximal bones of the sacrum of higher vertebrates, and is considered to be equivalent to the fusion of the tibial bone and the intermediate medium of many lower vertebrates [talus]. It bears the weight of the human body and is related to the ankle and calf related nodes Of bone. Is a short bone, located between the tibia, fibula and calcaneus, divided into three parts of the head and neck body.

Chinese name

Talus

Foreign name

astragalus

Pinyin

jù g

classification

Paleontology

Blood supply of talus and talus and its clinical significance

The talus blood supply comes from the three main arteries in the lower leg, namely the posterior tibial artery, anterior tibial artery, and peroneal artery, and their anastomosis with each other.

1. The posterior tibial artery, the posterior tibial artery is sent from the proximal end to the distal end in order to send the posterior nodular branch, triangular branch and tarsal canal artery to supply the talus.

2. Anterior tibial artery. The anterior tibial artery is renamed the dorsal foot artery at the ankle plane. The anterior and lateral ankle arteries are emitted at the ankle plane. There are internal and lateral iliac arteries below it, and branches from these small arteries supply talus.

3. The peroneal artery, the peroneal artery provides blood supply to the talus from two aspects. One is the peroneal branch of the peroneal artery, and the other is the posterior nodular branch. The peroneal branch of the peroneal artery penetrates the interosseous membrane 1.5 to 2.5cm above the tibiofibular joint and walks forward and downward. After anastomosis with the anterior malleolus artery, the proximal sacral sinus artery is issued. It accounts for 12.5%. At this time, the anterior malleolus artery is relatively large. The main trunk of the peroneal artery protrudes from the ankle joint inward to the posterior nodular branch, which coincides with the branch of the posterior tibial artery and the calcaneal branch.

4. Vascular anastomosis Fills any one of the three main arteries in the lower part of the calf, and the other two can be filled quickly, indicating that they are not independent of each other. Extensive vascular anastomosis between the branches of the posterior tibial artery, anterior tibial artery, and peroneal artery supplying the talus was observed on the specimens, with different shapes. In addition to the direct anastomosis between different arteries, a clear plexiform vascular anastomosis network appeared in the medial region of the talus in 6 specimens, accounting for 25%. The same situation occurred in the sacral sinus area at a rate of 33.3%. Below the talus, the tarsal sinus artery and the tarsal canal artery fit in the tarsal canal, connecting the vascular network on the inside and outside of the talus from below. In the anastomosis of the sacral canal, 14 sides were direct anastomosis, 6 sides were plexiform anastomosis, and the other 4 sides had no clear external osteoarterial anastomosis. Due to the perfusion technique and the dissection operation, many small details were lost Vascular anastomosis, there should be far more vascular anastomosis than we have observed. We have every reason to believe that the talus is at the center of a huge network of blood vessels. Moreover, the sacral canal, the sacral sinus, the talar neck and the medial side of the talar body are formed by the triangular branch, the sacral canal artery, the sacral sinus artery, the superior cervical branch and their anastomotic vascular network. An irregular anastomotic network of annular arteries, which we call the talar artery ring, intersects the talar long axis obliquely from back to front. In this arterial ring, the tarsal canal arteries appear smaller than the triangular branches and tarsal sinus arteries and are therefore relatively minor.

Talar talus pathological changes

1. Talus body ischemic necrosis

Hawkins (1970) classified talar neck fractures into three types. The previous reports of ischemic necrosis rates were 0% to 15% for type I, 20% to 30% for type II, and 84% to 100% for type III. The necrosis rate is related to the severity of the blood supply damage. We speculate that during talar fracture dislocation, if only one element of the arterial ring is destroyed, the possibility of necrosis is very low, such as type fracture; if two elements are destroyed, the necrosis rate will increase, such as type fracture. ; If more than three factors are destroyed, there will be a high rate of ischemic necrosis, such as type III fractures. In type II and type III fractures, because the proximal bone mass is generally displaced postero-medially, the triangular branch is likely to maintain a complete supply artery, which is of great significance for prognosis. The occurrence of ischemic necrosis after talar fracture is not only related to the degree of injury, but also to the measures taken. During the treatment of the fracture, care must be taken to protect the undamaged artery, especially the medial triangular branch.

2 , talar cartilage damage

It is one of the main causes of chronic ankle joint pain. Patients with talar cartilage injuries are relatively young, mostly males between 20 and 30 years old. About 10% of talar cartilage injuries can occur on both sides at the same time. The talar cartilage injury refers to the localized osteochondral injury of the talar block, which is the injury that affects the cartilage surface and / or subchondral bone of the talar fornix joint. It is manifested as local articular cartilage exfoliation, and talar cartilage damage occurs in the medial and lateral margins of the middle part of the talar fornix. It can be divided into lateral fornix injury and medial fornix injury. Tallar cartilage injury that occurs in the medial talus fornix is more common than lateral fornix injury. And the size and depth of the lesions are heavier.

The clinical manifestations are mostly pain after ankle weight bearing and after exercise, rest can be relieved, and the symptoms recur, but the entire course is delayed and gradually aggravated. The specific etiology is not clear. The related literature indicates that it may be repeated Traumas such as sprains and fractures may also be related to poor local blood flow and cartilage malnutrition.

Mild swelling of the ankle joint was observed during clinical examination. The tenderness of the medial or lateral ankle was obvious. The mobility of the ankle dorsiflexion and flexion was slightly limited compared with the healthy side. Some patients may have positive lateral stress test and positive ankle drawer test. It needs to be differentiated from neurogenic or vasogenic ankle pain.

Nuclear magnetic resonance plays an extremely important role in the diagnosis of talar cartilage damage. Nuclear magnetic resonance can detect and grade osteochondral damage, and is one of the best non-invasive examination methods for evaluating osteochondral damage. Mintz et al. Proposed a MRI staging system: stage 0, normal; stage , the articular cartilage surface remained intact but showed a high signal on T2WI; stage , fibrils on the articular surface formed or cracked, but the subchondral bone was not involved; Stage III, cartilage drape or subchondral bone exposure; stage IV. There are loose, non-displaced bone fragments; stage V, there are displaced bone fragments.

The diagnosis of talar osteochondral injury with clear diagnosis is ineffective with conservative treatment. Patients with stage to V and lesion diameter> 1.5cm tend to be surgically treated. Traditional and mature surgical methods such as drilling, microfracture, grinding arthroplasty, retrograde drilling, etc. The tissue repaired after the operation is fibrocartilage, which has poor wear resistance and unsatisfactory clinical results. With the development of minimally invasive technology, new surgical methods such as cartilage transplantation, autologous chondrocyte transplantation, bone transplantation, and prosthetic replacement have gradually matured. Arthroscopy has become the main surgical method for treating talar cartilage damage. Arthroscopy has been routinely applied abroad. For the treatment of talar cartilage damage, some scholars in China have started arthroscopy-assisted autologous osteochondral transplantation and achieved initial results. For large-scale cartilage defects, it is difficult to accept autologous cartilage, and allogeneic osteochondral transplantation can be used. Allogeneic osteochondral transplantation is beneficial to repair the articular surface and avoids the risk of donor site damage, but it has problems such as long recovery time, rejection, and limited cartilage viability.