LOWER LEG, ANKLE, AND FOOT

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CHAPTER 12

LOWER LEG, ANKLE, AND FOOT
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Précis of the Lower Leg, Ankle, and Foot Assessment*

History

Observation

Examination

Active movements, weight-bearing (standing)

Active movements, non-weight-bearing (sitting or supine lying)

Special tests (sitting)

Passive movements (supine lying)

Resisted isometric movements (supine lying)

Special tests (supine lying)

Reflexes and cutaneous distribution (supine lying)

Joint play movements (supine and side lying)

Palpation (supine lying and prone lying)

Special tests (prone lying)

Functional assessment (standing)

Special tests (standing)

Diagnostic imaging

*The précis is shown in an order that limits the amount of movement the patient must do but ensures that all necessary structures are tested; it does not follow the order of the text. After any assessment, the patient should be warned that symptoms may be exacerbated by the assessment.

SELECTED MOVEMENTS

ACTIVE MOVEMENTS image

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Figure 12-1 Active movements (weight-bearing posture). A, Plantar flexion. B, Dorsiflexion. C, Supination. D, Pronation. E, Toe extension. F, Toe flexion.

Toe Flexion, Extension, Abduction, and Adduction

INDICATIONS OF A POSITIVE TEST

Extension of the toes occurs at the metatarsophalangeal and proximal and distal interphalangeal joints. Extension of the great toe occurs primarily at the metatarsophalangeal joint (70°); minimal or no extension occurs at the interphalangeal joint. For the great toe, 45° flexion occurs at the metatarsophalangeal joint, and 90° occurs at the interphalangeal joint. For the lateral four toes, extension occurs primarily at the metatarsophalangeal (40°) and distal interphalangeal (30°) joints.

Extension at the proximal interphalangeal joins is negligible. For the lateral four toes, 40° flexion occurs at the metatarsophalangeal joints, 35° occurs at the proximal interphalangeal joints, and 60° occurs at the distal interphalangeal joints. If the ROM is less than this or is less than for the unaffected leg, it is restricted for some reason.

Abduction and adduction of the toes are measured with the second toe as midline. Although the ROM of abduction can be measured, this is not usually done. The common practice is to ask the patient to spread the toes and then bring them back together (“scrunching” the toes). The amount and quality of these movements are compared with those of the unaffected side.

SPECIAL TESTS FOR NEUTRAL POSITION OF THE TALUS

Relevant Special Tests

Definition

The neutral position of the talus often is referred to as the neutral or balanced position of the foot. This so-called neutral position is an ideal position that, in reality, is not commonly found in people in normal weight bearing. For most patients, the subtalar joint and the calcaneus normally are in slight valgus, with the forefoot in slight varus. The tibia also is in slight varus, so each joint slightly compensates for the adjacent one. The neutral position is used as a starting position to determine foot and leg deviations. Functional asymmetry may occur in the lower limb in normal standing. If so, the examiner should put the talus in the neutral position to see whether the asymmetry remains. If it does, anatomical or structural asymmetry is a factor, as well as functional asymmetry. If the asymmetry disappears, only functional asymmetry is present, which often is easier to treat.

Relevant Signs and Symptoms

The signs and symptoms depend on the pathological condition. Talar malalignment can manifest as pain in the foot, knee, hip, pelvis, or low back. Because talar malalignment results in compensations in other regions, most associated pathological conditions become problematic gradually. Generally, the patient cannot identify a specific mechanism of injury. Symptoms increase with use and lessen with rest. Positions or activities that require end-range dorsiflexion are the most problematic, because biomechanically, altered talus mechanics affect this most significantly. The ankle mortise must spread to accommodate the wider anterior aspect of the talus. If the talus is malpositioned, the talus may not be able to track through the mortise as efficiently or completely.

A sharp pain or pinching may be noted with end-range dorsiflexion. Hip lateral rotation or increased foot pronation may be noted during the middle to late stages of the stance phase of gait as a compensation for the lack of ankle dorsiflexion.

Mechanism of Injury

Malalignments may or may not be the result of previous injuries. Because of this, a mechanism of injury may or may not exist. Talar malalignment may be the result of previous injuries, repetitive use, leg length discrepancies, or genetics. Inversion ankle sprains may result in an osteochondral lesion, or bone bruise, on the medial aspect of the talus. Conversely, eversion ankle sprains can result in lesions or bruising on the lateral aspect of the talus. Either of these lesions, medial or lateral, could prevent proper tracking and alignment of the talus as it moves through the ankle mortise.

RELIABILITY/SPECIFICITY/SENSITIVITY COMPARISON11–16

  Validity Interrater Reliability Intrarater Reliability
Neutral position of the talus (weight-bearing position) Unknown 0.15-0.79 0.14-0.85
Neutral position of the talus (supine) Unknown Unknown Unknown
Neutral position of the talus (prone) Unknown 0.25 0.06-0.77

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NEUTRAL POSITION OF THE TALUS (PRONE)11–13,17–20 image

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Figure 12-3 Determining the neutral position of the subtalar joints in the prone position. A, Side view. B, Superior view.

NEUTRAL POSITION OF THE TALUS (SUPINE)14,15,17–20 image

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Figure 12-4 Determining the neutral position of the subtalar joint in the supine position.

NEUTRAL POSITION OF THE TALUS (WEIGHT-BEARING POSITION)11,13,16,18,21,22 image

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Figure 12-5 Determining the neutral position of the subtalar joint in standing (weight bearing).

CLINICAL NOTE/CAUTION

• Mueller et al.13 described a progression of neutral talus positions in standing (i.e., the navicular drop test) to quantify midfoot mobility and its effect on other parts of the kinetic chain. With a small, rigid ruler, the examiner first measures the height of the navicular from the floor in the neutral talus position, using the most prominent part of the navicular tuberosity; the height of the navicular in normal relaxed standing then is measured. The difference, called the navicular drop, indicates the amount of foot pronation or flattening of the medial longitudinal arch during standing. Any measurement greater than 10 mm is considered abnormal.

SPECIAL TESTS FOR ALIGNMENT

Relevant Special Tests

Epidemiology and Demographics

Few population-based studies have examined the prevalence of foot pain in the general population. Causal relationships between specific malalignments and injuries have been difficult to verify. In a random sampling of people in Australia, foot pain affected nearly 1 in 5 individuals. The pain was associated with increased age, female gender, obesity, and pain in other body regions, and it had a significant detrimental impact on health-related quality of life. The overall prevalence reported in this study was higher than that reported in the Cheshire Foot Pain and Disability Survey in the United Kingdom (10%). However, it was lower than the prevalence rates reported in two studies in the United States: the National Health Interview Survey in the United States (24%) and the Framingham Foot Study (28%).6–10

Relevant Signs and Symptoms

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