Ankle Range of Motion

Ankle Range of Motion is divided into active range of motion (AROM) and passive range of motion (PROM), with overpressure being superimposed at the end of available range to assess the end feel.

AROM tests are used to assess the patient’s willingness to move and the presence of movement restriction patterns such as a capsular or noncapsular pattern.

The neutral position of the foot with the ankle is a plantigrade (right-angled) position. That range and stability need to be compared with the other side and documented.

The functional normal range of motion for ankle that is required for normal gait is 15° of plantarflexion (required for normal push of) and 15° of dorsiflexion (deceleration of heel strike phase of gait and squatting). It is important to evaluate the active and passive range of motion and to document any restriction in the movement leading to deformation.

Ankle Range of Motion Movements

Foot and ankle Range of Motion includes the following movements:

1. Ankle Plantar flexion
2. Ankle Dorsi flexion
3. Supination
4. Pronation
5. Hindfoot inversion
6. Hindfoot eversion
7. Toe flexion
8. Toe extension

See Also: Ankle Anatomy

Ankle Dorsi flexion

The patient lies in the supine position, with the knee slightly flexed and supported by a pillow, while the clinician stands at the foot at the table, facing the patient.

Active Ankle Dorsi flexion is initially performed with the knee flexed. Care must be taken to prevent pronation at the subtalar and oblique midtarsal joint during dorsiflexion. The foot is slightly inverted to lock the longitudinal arch. Passive overpressure is applied.

With the knee flexed to approximately 90 degrees, the length of the soleus muscle is examined. Passive overpressure into dorsiflexion when the knee is flexed assesses the joint motion, as well as the soleus length. The soleus is implicated if pain is produced in this test, especially if resisted plantar flexion is painful or more painful with the knee flexed than with the knee extended.

With the knee flexed, 20 degrees of dorsiflexion past the anatomic position (the foot at 90 degrees to the bones of the leg) is found in the normally flexible person. The flexibility of the soleus muscle may also be assessed in standing in able-bodied individuals by asking the patient to perform a deep squat or a lunge.

Squat: If the muscle length is normal, the patient should be able to place the whole foot on the floor, including the heel, while in the full squat position. If the soleus is short, the heel will not touch the floor.

Lunge: A standard goniometer is aligned along the lateral aspect of the leg and the floor. The subject steadies themselves and then performs a weight-bearing lunge maneuver. The angle recorded on the goniometer indicates the range of dorsiflexion under load.

If the goniometer is set so that vertical is zero, the arm of the goniometer always aligns to the vertical and the scale rotates to indicate the inclination from the vertical.

This angle is then recorded as the ankle dorsiflexion range. This method is considered the most appropriate method of measuring ankle dorsiflexion range, as it reflects the functionally available range for the individual.

To assess the length of the gastrocnemius, the patient is placed in the supine position with the knee extended, and the ankle positioned in subtalar neutral. The patient is then asked to dorsiflex the ankle. Passive overpressure into dorsiflexion is applied.

The normal range is 20 degrees. If the gastrocnemius is shortened, dorsiflexion of the ankle will be reduced as the knee is extended and increased as the knee is flexed.

A muscular end-feel should be felt with the knee extended, and a capsular end-feel should be felt with the knee flexed.

Chronic adaptive shortening of the soleus muscle can be caused by excessive running, a weak posterior tibialis, or a weak quadriceps. Adaptive shortening of the soleus can result in forefoot pronation and a valgus stress at the knee.

A decrease in the flexibility of the gastrocnemius can result from a number of dysfunctions, including dysfunction of the subtalar joint or transtarsal joint, an ankle sprain, high heeled footwear, or poor gait/running mechanics.

See Also: Gait Cycle

Ankle Plantar Flexion

The patient is placed in the supine position, while the clinician stands at the foot of the table, facing the patient. The patient is asked to plantar flex the ankle. Plantar flexion of the ankle is approximately 30–50 degrees. When tested in weight-bearing with the unilateral heel raise, heel inversion should be seen to occur. Failure of the foot to invert may indicate instability of the foot/ ankle, posterior tibialis dysfunction, or adaptive shortening.

Hindfoot Inversion (Supination) and Hindfoot Eversion (Pronation)

Both hindfoot inversion and hindfoot eversion are tested by lining up the longitudinal axis of the leg and vertical axis of the calcaneus. Passive motion of hindfoot inversion(supination) is normally 20 degrees. The amount of hindfoot eversion (pronation) is normally 10 degrees.

Great Toe Motion

The patient is positioned in supine, with the leg being supported by a pillow, while the clinician stands at the foot at the table, facing the patient. Active extension of the great toe is performed and assisted passively without dorsiflexing the first ray.

The amount of posterior (dorsal) mobility is usually classified as normal, hypomobile, or hypermobile.

Although this method of assessment is common, its reliability and validity have been shown to be poor. Extension of the great toe occurs primarily at the MTP joint. Passive extension of the great toe at the MTP joint should demonstrate elevation of the medial longitudinal arch (windlass effect), and external rotation of the tibia. Passive MTP joint extension of between 55 and 90 degrees is necessary at terminal stance, depending on length of stride, shoe flexibility, and toe-in/toe-out foot placement angle. 45 degrees of first MTP flexion and 90 degrees of IP joint flexion are considered normal.

See Also: Foot Anatomy

Motion	Normal Range (Degrees)
Plantar flexion	50
Dorsiflexion	20
Supination	45-60
Pronation	15-30
Hindfoot inversion	20
Hindfoot eversion	10
Toe flexion	Great toe: MTP = 45; IP = 90 Lateral four toes: MTP = 40; PIP = 35; DIP = 60
Toe extension	Great toe: MTP = 70; IP = 0 Lateral four toes: MTP = 40; PIP = 0; DIP = 30

References

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