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

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 COMPARISON1116

  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)1113,1720 image

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

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%).610

Relevant Signs and Symptoms

The signs and symptoms depend on the pathological condition. Malalignment of the lower leg and foot generally results in overuse injuries. These may manifest as pain in the foot, knee, hip, pelvis, or low back. With most overuse injuries, the symptoms become gradually problematic. Generally the patient cannot identify a specific mechanism of injury. Symptoms increase with use and lessen with rest. Positions or activities that place the foot and lower leg at the end ranges of motion may produce a sharper, more localized pain in the affected area. Often, positional malalignments may be the result of protection and guarding by the muscles in the region. If the alignment is due to protection of neural or vascular structures, neural or vascular symptoms (or both), such as numbness, tingling, coldness, or weakness, may be present with overuse.

Mechanism of Injury

Malalignments may or may not be the result of previous injuries. Consequently, there may or may not be a mechanism of injury. Leg and heel alignment and forefoot to heel alignment issues may be the result of previous injuries, repetitive use, leg length discrepancies, or genetics. Injuries to the lower extremity in childhood often can result in structural abnormalities in the lower extremity; over time, the foot and ankle adapt to compensate for the structural changes.

RELIABILITY/SPECIFICITY/SENSITIVITY COMPARISON23,24

  Leg-Rearfoot (Heel) Alignment Forefoot-Rearfoot (Heel)Alignment
Validity Unknown Unknown
Interrater reliability Unknown 0.86
Intrarater reliability 0.86 0.88
Specificity Unknown Unknown
Sensitivity Unknown Unknown

LEG-REARFOOT (HEEL) ALIGNMENT20,23 image

TEST PROCEDURE

Starting with the unaffected leg, the examiner places a mark over the midline of the calcaneus at the insertion of the Achilles tendon. The examiner makes a second mark approximately 1 cm distal to the first mark and as close to the midline of the calcaneus as possible. A calcaneal line then is made to join the two marks. Next, the examiner makes two marks on the lower third of the leg in the midline along the Achilles tendon. These two marks are joined, forming the tibial line, which represents the longitudinal axis of the tibia.

The examiner then places the subtalar joint in the prone neutral position (see the previous test). While the subtalar joint is held in neutral, the examiner looks at the two lines to see whether they form a single straight line or an angle, and if the latter, how much of an angle.

SPECIAL TEST FOR TIBIAL TORSION

Relevant Special Test

Mechanism of Injury

The lower extremity commonly compensates for tibial torsions. Internal or medial torsion causes the foot to adduct. In response, the patient attempts to compensate by everting the foot or by laterally rotating at the hip. Similarly, individuals with external or lateral tibial torsion invert at the foot and medially rotate at the hip as a method of compensation. These compensations produce abnormal stresses in the knee, foot, hip, pelvis, and low back. Over time, these regions begin to “break down,” and a pathological condition ensues. Medial torsion often improves as a child matures. Conversely, lateral torsion often worsens.

When testing for tibial torsion, the examiner must realize that some lateral tibial torsion is normally present (13° to 18° in adults, less in children). If tibial torsion is more than 18°, it is referred to as a toe-out position. If tibial torsion is less than 13°, it is referred to as a toe-in position. A person with excessive toeing-in sometimes is referred to as “pigeon toed,” a condition that may be caused by medial tibial torsion, medial femoral torsion, or excessive femoral anteversion.

TIBIAL TORSION TEST30,31 image

SPECIAL TESTS FOR LIGAMENTOUS INSTABILITY

Relevant Special Tests

Definition

Ligamentous instability in the foot and ankle generally occurs in association with an ankle or foot sprain. Sprains occur when the ligament is tensioned beyond its physiological capacity; this results in a partial or complete tear of the ligament. When this occurs, structural integrity in the associated joint is lost.

Ankle sprains are classified into three categories:3235

Mechanism of Injury

ANTERIOR DRAWER TEST3648 image

INDICATIONS OF A POSITIVE TEST

A positive result may be obtained on the anterior drawer test if only the anterior talofibular ligament is torn; however, anterior translation is greater if both the anterior talofibular and calcaneofibular ligaments are torn, especially if the foot is tested in dorsiflexion. Sometimes, a dimple appears over the area of the anterior talofibular ligament on anterior translation (dimple, or suction, sign) if pain, muscle spasm, and swelling are minimal. If straight anterior movement or translation occurs, the test result indicates both medial and lateral ligament insufficiencies. This bilateral finding, which often is more evident in dorsiflexion, means that the superficial and deep deltoid ligaments, as well as the anterior talofibular ligament and anterolateral capsule, have been torn. If the tear is on only one side, only that side translates forward more than normal. For example, with a lateral tear, the lateral side translates forward, causing medial rotation of the talus and resulting in anterolateral rotary instability, which is increasingly evident with increased plantar flexion of the foot.

TALAR TILT TEST37,44,45,47,50,51 image

TEST PROCEDURE

The unaffected ankle is tested first. One of the examiner’s hands is placed anterior to the tibia on top of the navicular, and the other hand is positioned posterior to the tibia over the calcaneus. The two thumbs are placed on the lateral aspect of the calcaneus. The foot is held in the anatomical position (90°), which brings the calcaneofibular ligament perpendicular to the long axis of the talus. The talus then is tilted first into adduction and then into abduction. Adduction tests the calcaneofibular ligament and, to some degree, the anterior talofibular ligament, by increasing the stress on the individual ligaments. Abduction stresses the deltoid ligament, primarily the tibionavicular, tibiocalcaneal, and posterior tibiotalar ligaments, which are components of the deltoid ligament. The two sides are compared.

EXTERNAL ROTATION STRESS TEST (KLEIGER TEST)38,44,5258 image

OTHER SPECIAL TESTS

JOINT PLAY MOVEMENTS

ANTERIOR-POSTERIOR GLIDE AT THE MIDTARSAL AND TARSOMETATARSAL JOINTS image

TEST PROCEDURE

• Step 1: The examiner stabilizes the navicular, talus, and calcaneus with one hand by grasping the bones in the web space, thumb, and fingers of the examiner’s hand. The examiner’s other hand is placed around the distal row of tarsal bones (cuneiforms and cuboid). If the hands are positioned properly, they should touch. An anteroposterior gliding movement of the distal row of tarsal bones is applied while the proximal row of tarsal bones is stabilized. The two feet are compared.

• Step 2: The examiner’s hands then are moved distally so that the stabilizing hand rests over the distal row of tarsal bones and the mobilizing hand rests over the proximal aspect of the metatarsal bones. Again, the hands should be positioned so that they touch. An anteroposterior gliding movement of the metatarsal bones is applied while the distal row of tarsal bones is stabilized. The two feet are compared.