Disorders of the foot and ankle

Question 1

What is the most common mechanism of any ankle fracture?

Answer 1

Inversion or eversion injury

Question 2

What needs to be considered in the healing of a fracture?

Answer 2

Co-morbidities, e.g. diabetes, neuropathy, peripheral vascular disease, smoking

Question 3

What can happen to the overlying soft tissues in an ankle fracture?

Answer 3

Fracture blisters are relatively common after ankle fractures and surgery often needs to delayed until
after the blisters have healed. Sometimes the skin over the fracture blister becomes necrotic, so healing can take a considerate amount of time.

Question 4

What is an open-ankle fracture?

Answer 4

Where the skin barrier is breached and there is a direct communication between the fracture and the
external environment. They require urgent surgery with extensive irrigation and debridement to reduce the risk of osteomyelitis

Question 5

The ankle joint and associated ligaments can be visualised as a ring in the coronal plane, what form the sides of the ring?

Answer 5

The proximal part of the ring is formed by the articular surfaces of the tibia and fibula, united at the inferior tibiofibular joint by syndesmotic ligaments.
* The medial side of the ring is formed by the medial (deltoid) ligament
* The inferior part of the ring is formed by the subtalar joint (between the talus and the calcaneus)
* The lateral side of the ring is formed by the lateral ligament complex of the ankle (anterior talofibular, talocalcaneal and posterior talofibular)

Question 6

In terms of the ring, what needs to be considered with an ankle fracture?

Answer 6

When dealing with what appears to be a single fracture of the ankle joint; it is likely to have occurred in association with ligament damage
elsewhere in the ‘ring’ (which would not be apparent on an X-ray).

Question 7

What happens when there is disruption of any two of the syndesmosis, medial or lateral
ligaments?

Answer 7

The ankle mortise becomes unstable and widens so that the talus can shift medially or laterally within the ankle joint. This is referred to as talar shift.

Question 8

How are stable ankle fractures treated?

Answer 8

They are usually treated non-operatively with an aircast boot or a fibreglass cast for comfort. These patients can weight-bear safely and there is a low rate of complications such as secondary osteoarthritis with stable ankle fractures.

Question 9

How are unstable ankle fractures treated?

Answer 9

They need surgical stabilisation. This can be highvrisk surgery in patients with diabetes or peripheral vascular disease.

Question 10

What is an ankle sprain?

Answer 10

An ankle sprain refers to a partial or complete tear of one or more ligaments of the ankle joint

Question 11

How are ankle sprains treated?

Answer 11

90% of these heal with just rest and time; those that do not heal can cause late ankle instability and sometimes require surgery

Question 12

What factors can contribute to an increases risk of ankle sprains?

Answer 12

• Weak muscles/tendons that cross the ankle joint, especially the peroneal
  muscles
• Weak or lax ankle ligaments – this can be hereditary or due to overstretching of ligaments as a result of repetitive ankle sprains
• Inadequate joint proprioception (i.e. sense of joint position)
• Slow neuromuscular response to an off-balance position
• Running on uneven surfaces
• Shoes with inadequate heel support
• Wearing high-heeled shoes – due to the weak position of the ankle joint
  with an elevated heel, and a small base of support

Question 13

How do ankle sprains usually occur?

Answer 13

Ankle sprains occur usually through excessive strain on the ligaments of the ankle. This can be caused by excessive external rotation, inversion or eversion of the foot due to an external force. When the foot is forced past its normal range of motion, the excess stress puts a strain on the ligaments. If the strain is great enough to pull a ligament past its yield point, the ligament becomes damaged or ‘sprained’.

Question 14

What is the most common mechanism of injury in an ankle sprain?

Answer 14

An inversion injury affecting a plantar-flexed and weightbearing foot.
In this injury, the anterior talofibular ligament is most at risk of sprain.

Question 15

What is an avulsion fracture?

Answer 15

An avulsion fracture occurs when a tendon or ligament is placed under
tension and instead of the tendon or ligament tearing, a fragment of bone is pulled off at the insertion site

Question 16

Who are Achilles tendon ruptures most common in?

Answer 16

Rupture of the Achilles tendon most commonly occurs in men aged 30-50 years during recreational sports (“weekend warriors”) that require bursts of jumping, pivoting, and running (e.g. tennis, badminton, football).

Question 17

What are the mechanisms of injury of an Achilles tendon rupture?

Answer 17

• Making a forceful push-off with an extended knee (e.g. during jumping)
• A fall with the foot outstretched in front and the ankle dorsiflexed, forcibly
  overstretching the tendon
• Falling from a height, or abruptly stepping into a hole or off a kerb.

Question 18

Where is the usual site of rupture in an Achilles tendon rupture?

Answer 18

The site of rupture is often the ‘vascular watershed’ area, approximately 6cm proximal to the insertion of the Achilles tendon (calcaneal tendon) onto the calcaneal
tuberosity. This is an area of decreased vascularity and thickness of the tendon, which together render it more susceptible to tearing.

Question 19

What are the symptoms and signs of an Achilles tendon rupture?

Answer 19

• A sudden and severe pain at the back of the ankle or in the calf (like being
  ‘kicked in the heel’)
• The sound of a loud pop or snap
• A palpable (and sometimes visible) gap or depression in the tendon
• Initial pain and swelling followed by bruising
• Inability to stand on tip toe or to push-off whilst walking

Question 20

What test is used to test for a ruptured Achilles tendon?

Answer 20

Thompson’s test

Question 21

Why is surgical reconstruction of the Achilles tendon difficult?

Answer 21

When the tendon ruptures, the two ends are frayed (like a mop head)

Question 22

How are most ruptured Achilles tendons treated?

Answer 22

Conservatively, with the foot being held in the correct position in an aircast boot. Surgery has a relatively high complication rate; 5-10% of patients
have wound complications because the overlying skin is thin and poorly vascularised.

Question 23

What is hallux valgus?

Answer 23

• Varus deviation of the first metatarsal
• Valgus deviation and/or lateral rotation of
  the hallux
• Prominence of the first metatarsal head,
  with or without an overlying callus

Question 24

What causes hallux valgus?

Answer 24

The cause if poorly understood. Footwear can exacerbate it if it is already present by keeping the hallux in valgus deviation. It can also
occur secondary to trauma, arthritic/metabolic conditions such as gout, rheumatoid arthritis and psoriatic arthritis and to connective tissue disorders that cause ligamentous
laxity e.g. Ehlers-Danlos syndrome. The association with ligamentous laxity probably also explains why bunions tend to ‘run in families’.

Question 25

What is the treatment for hallus valgus?

Answer 25

Surgery should not be carried out for cosmetic reasons alone as it may convert a foot that is painless into a foot that is painful. Surgery involves a metatarsal osteotomy (cutting through the metatarsal bone) and realigning the fragments. A similar osteotomy may also be needed in the proximal phalanx of the great toe.

Question 26

What is hallux rigidus?

Answer 26

Hallux rigidus is osteoarthritis (OA) of the 1st metatarsophalangeal joint (MTPJ), resulting in stiffness of this joint (hence ‘rigidus’).

Question 27

What are the symptoms of hallux rigidus?

Answer 27

The commonest symptom is pain in the MTPJ on walking and on attempted dorsiflexion of the toe. In severe cases, the pain may be present at rest. Patients tend to compensate for the pain by walking on the outside of their foot (i.e. inverting the foot and walking on the lateral border).

Question 28

What problems are associated with hallux rigidus?

Answer 28

The range of dorsiflexion of the toe becomes severely restricted due to the arthritis, although plantar flexion is usually retained. A dorsal bunion (osteophyte) may develop on top of the joint and rub on the patient’s shoes.

Question 29

Describe these terms for surgical management of osteoarthritis: Arthroplasty Arthrodesis Excision arthroplasty Osteotomy

Answer 29

* Arthroplasty = joint replacement * Arthrodesis = joint fusion * Excision arthroplasty = surgical removal of the joint with interposition of soft tissue (e.g. a rolled-up tendon, between the bone ends) * Osteotomy = surgical cutting of a bone to allow realignment (to take the load of the affected part of the joint)

Question 30

What is the initial treatment for hallux rigidus?

Answer 30

Initially, treatment of hallux rigidus involves activity modification, analgesia, orthotics or aids and sometimes intra-articular steroid injections.

Question 31

If conservative management of hallux rigidus fails, what surgery is considered?

Answer 31

The current ‘gold standard’ treatment is arthrodesis (fusion) of the 1st MTPJ. In this operation, the joint is excised so that it is effectively replaced by a ‘fracture’. The ‘fracture’ is then stabilised with screws and normal fracture healing subsequently fuses the joint.

Question 32

What is different about OA of the ankle joint?

Answer 32

A major difference between OA of the ankle and that of the hip of knee is that nearly all cases of OA of the ankle are secondary arthritis. 70-80% of cases occur in a joint that has previously suffered trauma (e.g. fracture, severe sprain). This is referred to as post-traumatic arthritis.

Question 33

What is used to treat OA of the ankle?

Answer 33

The gold standard treatment for OA of the ankle is arthrodesis (fusion). The results from ankle fusion are very good. Patients can walk very well after an ankle fusion as they still have mobility of the mid-foot and fore-foot. There is often no discernible limp.

Question 34

What is claw toe?

Answer 34

Claw toes often affect all four of the small toes at the same time. The toes are hyperextended at the MTPJ and flexed at the PIP joint (and sometimes also at the DIP joint so that the toe curls under the foot). Corns may develop over the dorsum of the toe or under the head of the metatarsal.

Question 36

What causes claw toe?

Answer 36

Claw toes result from a muscle imbalance which causes the ligaments and tendons to become unnaturally tight. This is usually due to neurological damage and may be secondary to conditions such as cerebral palsy, stroke, diabetes or alcohol dependence. Trauma, inflammation and rheumatoid arthritis can also cause claw toe.

Question 37

What is hammer toe and mallet toe?

Answer 37

Hammer toe is a deformity in which the toe is flexed at the PIPJ, whereas a mallet toe is flexed at the DIPJ. These deformities can affect any toe but are most common in the second toe.

Question 38

What causes hammer toe and mallet toe?

Answer 38

Causes include ill-fitting pointed shoes, and pressure on the second toe from an adjacent hallux valgus. If a tight shoe causes a toe to stay in a flexed position for too long, the muscles contract and shorten. This makes it harder to extend the toe. Over time, the muscles cannot extend the toe, even when the shoes are not being worn

Question 39

What are curly toes?

Answer 39

Curly toes are congenital and usually involve the 3rd to 5th digits. They are usually bilateral and are more common in those with a family history of curly toes. Curly toes are thought to develop because the tendons of the flexor digitorum longus (FDL) or flexor digitorum brevis (an intrinsic muscle of the foot) are too tight.

Question 40

What are the two types of Achilles tendinopathy?

Answer 40

* At the point of insertion of the Achilles tendon into the calcaneum (insertional tendinopathy) * At the vascular ‘watershed’ area within the Achilles tendon (non-insertional tendinopathy).

Question 41

What causes Achilles tendinopathy?

Answer 41

Achilles tendinopathy often follows many years of overuse (e.g. long distance runners, sprinters), especially those whose training regimens are poor. However, it can also occur in people who are inactive. Other risk factors include obesity and diabetes.

Question 42

How is Achilles tendinopathy treated?

Answer 42

Treatment involves physiotherapy, especially eccentric stretching exercises, to try and improve the vascularity of the tendon and promote healing.

Question 43

What are the symptoms and signs of Achilles tendinopathy?

Answer 43

* Pain and stiffness along the Achilles tendon in the morning * Pain in the tendon or at the back of the heel that worsens with activity * Severe pain 24 hours after exercising * Thickening of the tendon * Swelling that is present all of the time but worsens during activity * A palpable bone spur (in insertional tendonitis)

Question 44

What is a flat foot (Pes planovalgus)

Answer 44

The term ‘flat foot’ implies that the medial arch of the foot has collapsed so that the medial border of the foot almost touches the ground. Valgus refers to the valgus angulation of the hindfoot

Question 45

What are the two types of flat feet?

Answer 45

Flexible and rigid

Question 46

What characterises flexible flat feet?

Answer 46

They have no medial arch whilst standing normally, but when standing on tip-toes, a normal medial arch appears and the hindfoot returns from valgus deviation into a normal alignment.

Question 47

What are rigid flat feet?

Answer 47

Rigid flat feet are always abnormal; they usually develop as a result of tarsal coalition (failure of the tarsal bones to separate during embryonic development). When patients with rigid flat feet stand on tiptoe, no arch appears and the hindfoot remains in valgus.

Question 48

How does adult acquired flatfoot occur?

Answer 48

In adults, an acquired flexible flat foot results from dysfunction of the tibialis posterior tendon, which usually supports the medial longitudinal arch of the foot whilst walking. The lack of support of the medial arch by tibialis posterior leads to stretching of the spring ligament (plantar calcaneonavicular ligament) and the plantar aponeurosis. Stretching of the ligaments results in the talar head being displaced inferomedially, flattening the medial longitudinal arch and producing lateral deviation of the hindfoot.

Question 49

How is adult acquired flat foot treated?

Answer 49

Symptoms improve in 80% of these patients following the use of orthotics (insoles) to support their medial arch and physiotherapy to improve muscle strength. Some patients, however, require either surgical reconstruction or, if secondary OA has developed, arthrodesis of the joints of their hindfoot.

Question 50

What is diabetic foot disease?

Answer 50

A combination of the loss of sensation due to peripheral neuropathy; ischaemia due to peripheral arterial disease and microvascular disease; and immunosuppression due to poor glycaemic control can lead to foot ulcers, severe infections and other serious complications. Because there is a loss of protective sensation, the patients will often continue to weight-bear on very significant soft tissue abnormalities, thereby exacerbating the problem.

Question 51

What is Charcot arthropathy?

Answer 51

Poorly-controlled diabetes can lead to Charcot arthropathy, which involves progressive destruction of the bones, joints and soft tissues. A combination of neuropathy, abnormal loading of the foot, repeated microtrauma (with non-healing microfractures), and metabolic abnormalities leads to inflammation causing osteolysis (bone resorption), fractures, dislocation and deformity.