Assistive Devices: Crutches

There are three major categories of ambulatory assistive devices: canes, crutches, and walkers. In this post, we will talk about crutches. Stay tuned for the next post about  walkers, and visit our previous post about canes.

Assistive devices are prescribed for a variety of reasons, including problems of balance, pain, fatigue, weakness, joint instability, excessive skeletal loading, and cosmesis.  Another primary function of assistive devices is to eliminate weight bearing fully or partially from a lower limb. This unloading occurs by transmission of force from the upper limbs to the floor by downward pressure on the assistive device.

Crutches

Crutches are used most frequently to improve balance and to either relieve weight bearing fully or partially on a lower extremity. They are typically used bilaterally, and function to increase the base of support (BOS), to improve lateral stability, and to allow the upper extremities to transfer body weight to the floor. This transfer of weight through the upper extremities permits functional ambulation while maintaining a restricted weight bearing status. there are two basic designs of crutches in frequent clinical use: axillary and forearm crutches.

Axillary Crutches

These assistive devices also are referred to as regular or standard crutches. They are made of lightweight wood or aluminum. their design includes an axillary bar, a handpiece, and double uprights joined distally by a single leg covered with a rubber suction tip (which should have a diameter of 1.5 to 3 in.). the single leg allows for height variations. Height adjustments for wooden crutches are accomplished by altering the placement of screws and wing bolts in predrilled holes. The design of most aluminum crutches incorporates a push-button pin mechanism for height adjustment similar to those found on aluminum canes. Both the overall height of the crutches as well as the height of the handgrip typically adjust in 1-in. increments. Axillary crutches are generally adjustable in adult sizes from approximately 48 to 60 in., with children`s and extra-long sizes available.

Advantages: it improves balance and lateral stability, and provide for functional ambulation with restricted weight bearing. They are easily adjusted, inexpensive when made of wood, and can be used for stair climbing.

Disadvantages: Because of the tripod stance required to use crutches and the resultant large BOS, crutches are awkward in small areas. For the same reason, the safety of the user may be compromised when ambulating in crowded areas. Another disadvantage is the tendency of some patients to lean on the axillary bar. This causes pressure at the radial groove (spiral groove) of the humerus, creating a situation of potential damage to the radial nerve as well as to adjacent vascular structures in the axilla.

Several methods are available for measuring axillary crutches. The most common use a standing or a supine position. Measurement from standing is most accurate and is the preferred approach.

Standing: From a supported standing position, crutches should be measured from a point approximately 2 in. below the axilla. The width of two fingers is often used to approximate this distance. During measurement, the distal end of the crutch should be resting at a point 2 in. lateral and 6 in. anterior to the foot. A general estimate of crutch height can be obtained prior to standing by subtracting 16 in. from the patient`s height. With the shoulders relaxed, the handpick should be adjusted to provide 20 to 30 degrees of elbow flexion.

Supine: From this position the measurement is taken from the anterior axillary fold to a surface point (mat or treatment table) 6 to 8 in. from the lateral border of the heel.

Forearm Crutches

These assistive devices are also known as Lofstrand and Canadian crutches. They are constructed of aluminum. Their design includes a single upright, a forearm cuff, and a handgrip. This catch adjusts both proximally to alter position of the forearm cuff and distally to alter the height of the crutch. adjustments are made using a push-button mechanism. The available heights of forearm crutches are indicated from handgrip to floor and are generally adjustable in adult sizes from 29 to 35 in., with children`s and extra long sizes available as well. The distal end of the crutch is covered with a rubber suction tip. The forearm cuffs are available with either a medial or anterior opening. The cuffs are made of metal and can be obtained with a plastic coating.

Advantages: The forearm cuff allows use of hands without the crutches becoming disengaged. They are easily adjusted and allow functional stair climbing activities. Many patients feel they are more cosmetic and they fit more easily into an automobile owing to the overall decreased height. They are also the most functional type of crutch for stair climbing activities for individuals wearing bilateral knee-ankle-foot orthoses (KAFOs).

Disadvantages: Forearm crutches provide less lateral support owing to the absence of an axially bar. The cuffs may be difficult to remove.

Standing is the position of choice for measuring forearm crutches. From a supported standing position, the distal end of the crutch should be positioned at a point 2 in. lateral and 6 in. anterior to the foot. With the shoulders relaxed the height should then be adjusted to provide 20 to 30 degrees of elbow flexion. The forearm cuff is adjusted separately. Cuff placement should be on the proximal third of the forearm, approximately 1 to 1.5 in. below the elbow.

Gait patterns for use of crutches

Gait patterns are selected on the basis of the patient`s balance, coordination, muscle function, and weight bearing status. The gait patterns differ significantly in their energy requirements, BOS, and the speed with which they can be executed.

Prior to initiating instruction in gait patterns, several important points should be emphasized to the patient:

1. During axillary crutch use, body weight should always be borne on the hands and not on the axillary bar. This will prevent pressure on both the vascular and nervous structures located in the axillary region.
2. Balance will be optimal by always maintaining a wide (tripod) BOS. Even when is a rest stance, the patient should be instructed to keep the crutches at least 4 in. to the front and to the side of each foot. The foot should not be allowed to achieve parallel alignment with the crutches. This will jeopardize anterior-posterior stability by decreasing the BOS.
3. When using standard crutches, the axillary bars should be held close to the chest wall to provide improved lateral stability.
4. The patient should also be cautioned about the importance of holding the head up and maintaining good postural alignment during ambulation.
5. Turning should be accomplished by stepping in a small circle rather than pivoting.

Three-point gait

In this type of gait three points of support contact the floor. It is used when a non-weightbearing status is required on one lower extremity. Body weight is borne on the crutches instead of on the affected lower extremity.

Partial Weightbearing Gait

This gait is a modification of the three-point pattern. During forward progression of the involved extremity, weight is borne partially on both crutches and on the affected extremity. During instruction in the partial weight bearing gait, emphasis should be placed on use of a normal heel-toe progression on the affected extremity. Often the term partial weight bearing is interpreted by the patient as meaning that only the toes or ball of the foot should contact the floor. Use of this positioning over a period of days or weeks will lead to heel cord tightness.

Four-point gait

This pattern provides a slow, stable gait as three points of floor contact are maintained. Weight is borne on both lower extremities and typically is used with bilateral involvement due to poor balance, incoordination, or muscle weakness. In this gait pattern one crutch is advanced and then the opposite lower limb is advanced. For example, the left crutch is moved forward, then the right lower extremity, followed by the right crutch and then the left lower extremity.

Two-point gait

This gait pattern is similar to the four-point gait. However, it is less stable because only two points of floor contact are maintained. Thus, use of this gait requires better balance. The two-point pattern more closely simulates normal gait, inasmuch as the opposite lower and upper extremities move together.

Two additional, less commonly used crutch gaits are the swing-to and swing-through patterns. These gaits are often used when there is bilateral lower extremity involvement, such as in Spinal Cord Injury. The swing-to gait involves forward movement of both crutches simultaneously, and the lower extremities “swing to” the crutches. In the swing-through gait, the crutches are moved forward together, but the lower extremities are swung beyond the crutches.

Assuming Standing and Seated Positions with Crutches

Coming to Standing 

• The patient moves forward in the chair.
• Crutches are placed together in a vertical position on the affected side.
• One hand is placed on the handpicks of the crutches; one on the armrest of the chair.
• The patient leans forward and pushes to a standing position.
• Once balance is gained, one crutch is cautiously placed under the axilla on the unaffected side.
• The second crutch is then carefully placed under the axilla on the affected side.
• A tripod stance is assumed.

Return to Sitting 

• As the patient approaches the chair, the patient turns in a small circle toward the uninvolved side.
• The patient backs up until the chair can be felt against the patient`s legs.
• Both crutches are placed in a vertical position (out from under axilla) on the affected side.
• One hand is placed on the handpicks of the crutches, one on the armrest of the chair.
• The patient lowers to the chair in a controlled manner.

Stair-Climbing Techniques

Crutches: Three-Point Gait

Ascending

1. The patient is positioned close to the foot of the stairs. The involved lower extremity is held back to prevent “catching” on the lip of the stairs.
2. The patient pushes down firmly on both handpicks of the crutches and leads up with the unaffected lower extremity.
3. The crutches are brought up to the stair that the unaffected lower extremity is now on.

Descending

1. The patient stands close to the edge of the stair so that the toes protrude slightly over the top. The involved lower extremity is held forward over the lower stair.
2. Both crutches are moved down together to the front half of the next step.
3. The patient pushes down firmly on both handpicks and lowers the unaffected lower extremity to the step that the crutches are now on.

Crutches: Partial Weightbearing Gait

Ascending

1. The patient is positioned close to the foot of the stairs.
2. The patient pushes down on both handpicks of the crutches and distributes weight partially on the crutches and partially on the affected lower extremity while the unaffected lower extremity leads up.
3. The involved lower extremity and crutches are then brought up together.

Descending

1. The patient stands close to the edge of the stair so that the toes protrude slightly over the top of the stair.
2. Both crutches are moved down together to the front half of the next step. The affected lower extremity is then lowered (depending on patient skill, these may be combined). Note: When crutches are not in floor contact, greater weight must be shifted to the uninvolved lower extremity to maintain a partial weight bearing status.
3. The uninvolved lower extremity is lowered to the step the crutches are now on.

Crutches: Two- and Four-Point Gait 

Ascending

1. The patient is positioned close to the foot of the stairs.
2. The right lower extremity is moved up and then the left lower extremity.
3. The right crutch is moved up and then the left crutch is moved up (patients with adequate balance may find it easier to move the crutches up together).

Descending 

1. The patient stands close to the edge of the stair.
2. The right crutch is moved down and then the left (may be combined).
3. The right lower extremity is moved down  and then the left.

Source: Susan B. O`Sullivan, Thomas J. Schmitz. Physical Rehabilitation.