1. Injuries of the Ankle

2. Achilles tendon injury
the tendon that connects the calf muscle (gastrocnemius) to the heel bone (calcaneus).
the tendon that is just below the skin at the back of the ankle.

3. Achilles tendon injury

4. Side View of Ruptured Achilles' Tendon
Side View of Ruptured Achilles' Tendon. Notice depression at site of rupture (red circle)

5. Action : -
When the gastrocnemius muscle (in the calf) contracts (shortens), the tendon which is attached from the muscle to the heel bone (calcaneus) moves.
As the muscle shortens, the tendon moves to point the foot downwards.
This is the action that allows a person to stand on one's toes, to run, to jump, to walk normally, and to go up and down stairs.

6. Diagnosis
History
a sudden snap in the lower calf associated with acute severe pain
may be able to ambulate with a limp, but he or she is unable to run, climb stairs, or stand on their toes.
loss of plantar flexion power in the foot.
swelling of the calf.
history of a recent increase in physical activity/training.
history of recent use of fluoroquinolones, corticosteroids, or of corticosteroid injections.
previous rupture of the affected tendon.

7. Physical examination tenderness, swelling, ecchymosis, and
tendon defects. 
A palpable gap in the Achilles tendon.
unable to stand on the toes on the affected side.

8. Clinical tests “Hyperdorsiflexion” sign –
With the patient prone and knees flexed to 90º, maximal passive dorsiflexion of both feet may reveal excessive dorsiflexion of the affected leg.
Thompson test –
 With the patient prone, squeezing the calf of the extended leg may demonstrate no passive plantar flexion of the foot if its Achilles tendon is ruptured.
O’Brien needle test – 
Insert a needle 10 cm proximal to the calcaneal insertion of the Achilles tendon. With passive dorsiflexion of the foot, the hub of the needle will tilt when the Achilles tendon is intact.

9. X – ray of the heel Lateral view of the heel
Ultrasound or MRI may help if the diagnosis is unclear (for example, to distinguish partial rupture from tendonitis).

10. Treatment Conservative : -
Immobilising the ankle in slight plantar flexion for 6 to 8 weeks
Surgery :
Direct surgical repair and immobilisation in a below – knee plaster cast with slight plantar flexion .

11. Differential diagnosis
Achilles tendonitis
Retrocalcaneal bursitis
Other ankle injuries
Ankle osteoarthritis
Deep vein thrombosis

12. Complications Achilles tendon contracture. Re-rupture. Prognosis
Achilles tendon injury has a good prognosis, but the slight loss of function may be very significant for the competitive athlete.
Surgical treatment of acute Achilles tendon ruptures significantly reduces the risk of re-rupture compared to non-operative treatment, but has a higher risk of other complications, including wound infection.
Athletes may be unable to resume full activities for one year.