Clinical examination of the lower leg, ankle and foot

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55

Clinical examination of the lower leg, ankle and foot

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History

Although the main question is the current problem – where the pain is now – it is best to try to obtain a chronological account, as summarized in Box 55.1. In order to work out the problem systematically, the questions asked should follow the order given below.

Box 55.1   Summary of history taking

If there was an injury:

If there was no injury:

Sometimes there will be some evolution in degree and localization of pain, swelling and functional disability during the weeks or months after the onset.

The examiner should also find out what sort of treatment the patient has already had, and what the results were.

The present complaints should be investigated further:

Because foot disorders cause pain while the foot is performing its function, walking or running will always be the provoking activities:

Further questioning should establish whether there are ‘twinges’ or instability:

• Do you have twinges, and when? A twinge in the foot is a very important symptom. It is a sudden, sharp pain, mostly occurring during walking. It should always be differentiated from ‘giving way’. In a twinge, there is only momentary pain and not a feeling of instability. By the time the patient realizes it, the pain has disappeared. A twinge is very often an indication of a momentary impaction of a loose body in the ankle or subtalar joint. If localized in the forefoot, it can be a symptom of Morton’s metatarsalgia or sesamoiditis.

• Do you have a feeling of instability? If so, describe it. Real instability of the ankle or foot is only important in sports. Normal walking or even running on a flat surface hardly ever causes a feeling of giving way. In the occasional case where this does happen, it is the result of neurological weakness of the peronei muscles, rather than of a ligamentous lesion.

Inspection

Inspection is first made in a standing position. The shape of the legs is evaluated: valgus or varus deformity is checked. The normal intermalleolar distance should not exceed 5 cm. A slight outward rotation of the tibiae is normal, with an outward pointing of the toes of about 15°. Exaggeration of this outward rotation can be caused by short calf muscles and results in a restricted step during walking and running.

The shape of the feet in a standing position is studied next. At the calcaneus there can be a valgus or varus deformity.

The longitudinal arch of the foot is then estimated: a cavus deformity or a flat foot may be identified. At the mid-tarsal region the shape and regularity of the bones is inspected and, at the forefoot, special attention is paid to the existence of an insufficient anterior arch, hallux valgus, claw toes, hammer toes or metatarsus inversus.

After inspection in the standing position, it is sometimes advisable to check the patient’s gait and how the shoes have worn down.

Inspection in the supine-lying position gives information about contours, shape, atrophy, colour of the skin, swelling, oedema, haematoma, the condition of the skin and nails, and the existence of callosities.

Sometimes a second inspection in a standing position may follow the routine functional examination, when special attention should be paid to:

Functional examinationimage

The foot is the most difficult moving part of the body to examine because a great number of strong structures, with little individual mobility, are condensed into a small volume. Testing each structure in turn without the help of a lever is a very difficult task and demands great technical and manual ability.

In the foot, the clinical tests consist of 18 movements (Box 55.2). Other than rising on tiptoe, the clinical examination is performed in the supine-lying position. Consecutively, the ankle joint, the subtalar joint, the midtarsal joints, the ligaments and the muscles are tested.

Box 55.2   Summary of movements of the foot

Rising on tiptoe

This movement (Fig. 55.1) is used to test the plantiflexor mechanism of the foot. If rising on tiptoe hurts and resisted eversion and inversion remain painless, the triceps surae muscles must be at fault. Because plantiflexion is almost entirely performed by the contraction of the triceps, rising on tiptoe will, in particular, test the integrity of triceps, the Achilles tendon and its insertion on the calcaneus. Note is taken of whether the movement is strong or weak, painless or painful.

If rising on tiptoe is painful, the following test distinguishes between the soleus and the gastrocnemius muscles. The patient lies prone and plantiflexion of the foot is resisted, first with the knee fully extended, then with the knee bent at a right angle. Flexing the knee relaxes both the gastrocnemii muscles but does not alter the pull at the soleus muscle. Hence abolition of pain when the muscle is tested during knee flexion incriminates the gastrocnemius muscle.

If rising on tiptoe is weak, a neurological lesion can be the cause. Apart from upper motor neurone lesions, peroneal atrophy and direct injury to the sciatic nerve, the common cause of painless weakness is a first and second sacral root palsy.

Rising on tiptoe is also very important in the diagnosis of Achilles tendon rupture. If the plantiflexor muscles are examined in the supine-lying position only, active plantiflexion is not found to be lost because the flexor hallucis longus, the flexor digitorum longus, the tibialis posterior and the peronei remain intact.

Tests for the ankle joint

The ankle joint is a simple joint, allowing, in normal circumstances, plantiflexion and dorsiflexion only. The range of movement is measured by estimating the angle joined by the longitudinal axis of the tibia and the dorsum of the foot.

Plantiflexion

Normally, an ankle can be plantiflexed until the dorsal aspect of the foot falls into line with the leg (Fig. 55.2). Plantiflexion is limited by the engagement of the heel via the Achilles tendon against the back of the tibia. Therefore the normal end-feel is soft.

Ligamentous tests at ankle and foot

Lateral ligaments

To test the outer structures of the ankle and foot, the examiner performs a strong inversion movement during full plantiflexion. Inversion produces a combination of varus at the subtalar joint and adduction/supination at the forefoot. This test stretches all the structures at the outer and anterior side: the lateral ligaments of the ankle, the subtalar joint and the midtarsal joints, together with the tendons of the peroneal and the extensor digitorum longus muscles.

Medial ligaments

A combined test is used: full plantiflexion at the ankle joint, together with valgus at the subtalar joint and abduction–pronation at the midtarsal joint. These movements stretch the anterior and middle portion of the deltoid ligament, the anterior tibiotalar ligament and the calcaneonavicular ligament. At the outer side, however, the posterior talofibular ligament can become painfully squeezed.

Tibiofibular ligaments

A strong varus movement applied to the talus held in a neutral position forces this bone as a wedge between the two malleoli, so testing the integrity of the distal tibiofibular ligaments. In a normal ‘mortice’, the strong tibiofibular and lateral collateral ligaments prevent separation of the tibia and fibula. When there is ligamentous rupture or laxity, the fibula can be pressed outwards, a circumstance that is detected by a palpable click when the tibia and the fibula engage after their momentary separation. In total rupture of the anterior talofibular or the calcaneofibular ligaments, this test will also be positive. Differentiation should then be made using the anterior drawer test (see p. 784).

Mobility of the subtalar joint

Varus and valgus

In order to move the calcaneus on the talus, the examiner must try to avoid any movement at the ankle joint. Because the width of the trochlear surface of the talus is smaller posteriorly than anteriorly, the medial and lateral surfaces of the body of the talus are gripped tightly during dorsiflexion of the ankle. Therefore the ankle must be forced into and kept in full dorsiflexion during varus–valgus movements.

Technique

The heel is firmly grasped between the two hands, the fingers clasped behind the heel. Dorsiflexion is performed by traction on the heel (Fig. 55.6). Because the test involves a very strong joint, with little mobility, and because it is hardly possible to obtain any leverage, the examiner must keep the heel as steady as possible. By swinging the upper half of the body, it is possible to gain a good idea of the range of motion.

A normal varus–valgus range is between 20° and 45°. Mobility should always be compared with the other side and the normal end-feel is soft. The varus movement also tests the integrity of the calcaneofibular ligament.

Passive tests for the midtarsal joints

Flexion–extension, pronation–supination, abduction–adduction

As the middle segment of the foot consists of several bones and joints, it is very difficult to assess isolated movement at the various joints. Therefore Cyriax considered the whole middle segment as one integrated structure – the midtarsal joint.

Because of anatomical characteristics, plantiflexion is often accompanied by some adduction and dorsiflexion by some abduction (see online chapter Applied anatomy of the lower leg, ankle and foot).

Pronation and supination also examine the inner and outer ligaments of the midfoot. Pronation tests the plantar calcaneonavicular ligament, whereas supination and adduction bring the calcaneocuboid ligament and the ligaments between cuboid and fifth metatarsal under stress.

Technique

First, the posterior segment (ankle and subtalar joints) must be stabilized. Therefore, the examiner uses the contralateral hand to pull strongly on the heel and force it into valgus. The traction forces the talus into the dorsiflexed position between both the malleoli, thus immobilizing the ankle joint, and the valgus position fixes the subtalar joint.

The ipsilateral hand encircles the forefoot, so that the thumb comes to lie under the metatarsal heads and the fingers at the dorsum of the metatarsal shafts. In this position, the examiner can easily perform plantiflexion–dorsiflexion in the foot by a simple pronation–supination movement of the arm. An adduction–abduction movement is achieved by an adduction–abduction movement of the wrist, and pronation–supination by a flexion–extension movement (Fig. 55.7). Although the range of movement varies considerably between individuals, it is surprising how much movement the normal midtarsal joints allow.

The end-feel in flexion–extension and in abduction–adduction is rather hard, whereas the end-feel in both rotations is soft.

Resisted movements

Resisted tests are always performed in a neutral position. No active movement of the joint is allowed. The examiner tries to evoke pure isometric contractions of the tested muscles. In order to avoid a false result, it is absolutely essential to keep the joint immobile during the contraction. Therefore a good immobilization technique is of great importance, especially when inversion and eversion are to be tested against resistance.

Technique

To stabilize the foot during resisted eversion, the patient’s leg is immobilized by the examiner’s ipsilateral hand, placed at the medial and distal end of the leg. The examiner uses the contralateral hand to apply counterpressure at the lateral border of the foot (Fig. 55.8).

During resisted inversion, the reverse is done: the contralateral hand fixes the leg at the distal lateral side and the ipsilateral hand, placed at the inner border, applies counterpressure.

Resisted dorsiflexion tests the tibialis anterior, extensor hallucis longus, extensor digitorum longus and the peroneus tertius.

The plantiflexor muscles tested are the triceps surae, tibialis posterior, flexor hallucis longus, flexor digitorum longus and peronei brevis and longus.

Resisted eversion tests the integrity of the peronei muscles but also the peroneus tertius and extensor digitorum longus.

Inversion against resistance tests the tibialis posterior and anterior, together with the flexor and extensor hallucis longus, and slightly tests the triceps surae.

Accessory tests

Cases with pain but a normal examination

It is possible for a foot to hurt and yet appear normal on clinical examination, probably because the momentary stress of the manual testing is insufficient to evoke pain. This happens particularly in athletes and ballet dancers who feel pain after exertion, i.e. after a strain far greater than any examiner can impose on the foot by mere clinical testing. In such cases, patients should stand up to demonstrate which particular movements hurt. If the pain only appears during or after training or exertion, the patient is asked to return when the pain has been provoked.

Clinical examination of the lower leg, ankle and foot is summarized in Box 55.3.

Box 55.3   Summary of the clinical examination

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