FRACTURE OF TALUS.pptx. .....

Fracture of talus

1. Dr.Akshay FRACTURE OF TALUS

2. Introduction Importance of talus: Takes part in weight transmission. Has a precarious blood supply. 3/5th of the bone is covered by articular cartilage. Sudden hyperextension causes fracture neck called "Aviators Astralagus ". of the forefoot.

3. Blood Supply Sixty percent is covered by articular surface, only limited surface is available for vascular perforation . No muscle originates or inserts into talus. All the three major arteries of the foot posterior tibial artery, anterior tibial artery and peroneal artery supply talus. T here is important contribution from capsular and ligamentous vessels. The branches of these arteries form an anterosuperior and inferior groups. The posteroinferior surface of the body has no blood supply .

4. Mechanism of Injury Fracture of the talar neck is produced by violent hyperextension of the ankle. If the force continues, the fracture is displaced and the surrounding joints may sublux or dislocate . Fracture of the body is usually a compression injury due to a fall from a height, or an everting force across the body, fracturing the lateral process (the snowboarders’ fracture ). Avulsion fractures are associated with ligament strains around the ankle and hindfoot .

5. Clinical Features The patient has most commonly been involved in a motor vehicle accident or has fallen from a height. The foot and ankle are painful and swollen; if the fracture is displaced, there may be an obvious deformity, or the skin may be tented or split. Tenting is a dangerous sign; if the fracture or dislocation is not promptly reduced, the skin may slough and become infected. The pulses should be checked and compared with those in the opposite foot.

6. Radiological Findings X-ray - Anteroposterior , lateral and oblique views are essential; CT scanning helps to identify associated injuries of the ankle and foot. Both malleoli, the ankle mortise, the talus and all the adjacent tarsal bones should be carefully assessed. Undisplaced fractures are not always easy to see, and sometimes even severely displaced fractures are missed in the initial assessment because of unfamiliarity with the normal appearance – sad but true.

7. Classification Fractures of the neck of the talus - These fractures are classified according to the system devised by Hawkins (1970) and modified by Canale (1978): Group I – undisplaced Group II – displaced (however little) and associated with subluxation or dislocation of the subtalar joint Group III – displaced, with dislocation of the body of the talus from the ankle joint Group IV – displaced vertical talar neck fracture with associated talonavicular joint disruption

8. Fractures of the head of the talus - This is a rare injury; the fracture usually involves the talonavicular joint. Fractures of the body of the talus - These are also uncommon. The fracture is often displaced and may cause distortion of the talocalcaneal joint. Rotational malalignment of the fragments is difficult to diagnose on plain x-ray examination; the deformity is best visualized by three-dimensional CT reconstruction.

9. Fractures of the lateral and posterior processes - These are usually associated with ankle ligament strains. It is sometimes difficult to distinguish between a fracture of the posterior process and a normal os trigonum . A simple rule is ‘if it’s not causing symptoms it doesn’t really matter’. Note - os trigonum is an accessory bone that sits in the back of the ankle near the heel bone. This occurs in 2.5-14% of normal feet. It is usually round, oval or triangular and varies in size. Osteochondral fractures - Osteochondral fractures following acute trauma usually occur on the lateral part of the dome of the talus. The diagnosis is often missed when the patient is first seen and may come to light only after CT or MRI scan.

10. Treatment – Undisplaced Fracture A split below-knee plaster is applied and, when the swelling has subsided, is replaced by a complete cast with the foot plantar flexed . Weight-bearing is not permitted for the first 4 weeks; thereafter, the plaster is removed, the fracture position is checked by x-ray, a new cast is applied and weight bearing is gradually introduced. Further plaster changes or use of an adjustable splintage boot will allow the foot to be brought up, slowly, to plantigrade ; physiotherapy is commenced. At 8–12 weeks the splintage is discarded and function is regained by normal use.

11. DISPLACED FRACTURES OF THE NECK Even the slightest displacement makes it a type II fracture, which needs to be reduced. If the skin is tight, reduction becomes urgent because of the risk of skin necrosis. Reduction must be perfect: (1) in order to ensure that the subtalar joint is mechanically sound; (2) to lessen the chance – or at any rate lessen the effects – of avascular necrosis.

12. Type II fractures C losed manipulation under general anaesthesia can be tried first . Traction is applied with the ankle in plantarflexion ; the foot is then steered into inversion or eversion to correct the displacement. The reduction is checked by x-ray ; A below-knee cast is applied (with the foot still in equinus ) and this is retained, non- weightbearing , for 4 weeks. Cast changes after that will allow the foot to be gradually brought up to plantigrade ; however, weightbearing is not permitted until there is evidence of union (8–12 weeks).

13. Type II fractures If closed reduction fails (which it often does), open reduction is essential ; Through an anteromedial incision the fracture is exposed and manipulated into position. Wider access can be obtained by pre-drilling and then osteotomizing the medial malleolus; after the talar fracture has been reduced, the malleolar fragment is fixed back in position with a screw. The position is checked by x-ray and the fracture is then fixed with two K-wires or a lag screw . Postoperatively a below knee cast is applied; weight bearing is not permitted until there are signs of union (8–12 weeks).

14. Type III fracture–dislocations It need urgent open reduction and internal fixation. The approach will depend on the fracture pattern and position of displaced fragments. Osteotomy of the medial malleolus might help; the malleolus is pre-drilled for screw fixation and osteotomized and retracted distally without injuring the deltoid ligament. This wide exposure is essential to permit removal of small fragments from the ankle joint and perfect reduction of the displaced talar body under direct vision; The position is checked by x-ray and the fracture is then fixed securely with screws. If there is the slightest doubt about the condition of the skin, the wound is left open and delayed primary closure carried out 5 days later. Postoperatively the foot is splinted and elevated until the swelling subsides; a below-knee cast or splintage boot is then applied, following the same routine as for type II injuries.

15. DISPLACED FRACTURES OF THE BODY Fractures through the body of the talus are usually displaced or comminuted and involve the ankle and/or the talocalcaneal joint; occasionally the fragments are completely dislocated. Minimal displacement can be accepted; a below knee non-weight bearing cast is applied for 6–8 weeks; this is then replaced by a weight bearing cast for another 4 weeks. Horizontal fractures that do not involve the ankle or subtalar joint are treated by closed reduction and cast immobilization.

16. DISPLACED FRACTURES OF THE BODY Displaced fractures with dislocation of the adjacent joints should be accurately reduced. In almost all cases open reduction and internal fixation will be needed. An osteotomy of the medial malleolus is useful for adequate exposure of the talus; the malleolus is predrilled before the osteotomy and fixed back into position after the talar fracture has been dealt with. The prognosis for these fractures is poor: there is a considerable incidence of malunion, joint incongruity, avascular necrosis and secondary osteoarthritis of the ankle or talocalcaneal joint.

17. DISPLACED FRACTURES OF THE HEAD The main problem is injury to the talonavicular joint. If the fragments are large enough, open reduction and internal fixation with screws is the recommended treatment. If there is much comminution, it may be better simply to excise the smaller fragments. Postoperative immobilization is the same as for other talar fractures.

18. FRACTURES OF THE TALAR PROCESSES If the fragment is large enough, open reduction and fixation with K-wires or small screws is advisable. Tiny fragments are left but can be removed later if they become symptomatic.

19. OSTEOCHONDRAL FRACTURES These small surface fractures of the dome of the talus usually occur with severe ankle sprains or subtalar dislocations. Most acute lesions can be treated by cast immobilization for 4–6 weeks. Occasionally a displaced fragment is large enough to warrant operative replacement and internal fixation. More often it is separated from its bed and is excised: the exposed bone is then drilled to encourage repair by fibrocartilage .

20. Open Fractures The injury is treated as an emergency. Under general anaesthesia , the wound is cleaned and debrided and all necrotic tissue is removed. The fracture is then dealt with as for closed injuries, except that the wound is left open and closed by delayed primary suture or skin grafting 5–7 days later, when swelling has subsided and it is certain that there is no infection. Sometimes , in open injuries, the talus is completely detached and lying in the wound. After adequate debridement and cleansing, the talus should be replaced in the mortise and stabilized, if necessary with crossed K-wires. Later definitive fixation is then performed.

21. Complications Malunion - Malunion may lead to distortion of the joint surface, limitation of movement and pain on weight bearing. Avascular Necrosis - Avascular necrosis of the body of the talus occurs in displaced fractures of the talar neck. Secondary Osteoarthritis - Osteoarthritis of the ankle and/or subtalar joints occurs some years after injury in over 50 per cent of patients with talar neck fractures. There are a number of causes: (1) articular damage due to the initial trauma; (2) malunion and distortion of the articular surface; (3) avascular necrosis of the talus.

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