Prosthetic Alignment in Gait Cycle

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Questions and Answers

What is the primary function of a hip-leveling guide?

To identify gait deviations in the transtibial amputee

To determine if the pelvis is level (correct)

To measure knee flexion during initial contact

To determine if the femur is displaced laterally during weight-bearing

During which phase of gait does the knee move over the foot?

Pre-swing

Initial contact

Loading response

Midstance (correct)

What is a common gait deviation resulting from a prosthesis that is too far inset?

Excessive valgus

Excessive inversion

Excessive eversion

Excessive varus (correct)

What is the recommended knee flexion angle during initial contact?

20 degrees Signup and view all the answers

What is a common cause of excessive inversion or eversion of the foot?

Misalignment of the prosthesis Signup and view all the answers

What is the purpose of dynamic alignment during gait training?

To identify gait deviations Signup and view all the answers

What is a common compensation for insufficient knee flexion?

Increased hip flexion Signup and view all the answers

What is the purpose of the loading response phase of gait?

To absorb shock Signup and view all the answers

During bench alignment of a Transtibial (TT) prosthesis, the socket is aligned with the knee flexed at what degree?

5° to 10° Signup and view all the answers

What is the purpose of placing the socket in 2° to 5° of varus (adduction) during bench alignment of a Transtibial (TT) prosthesis?

All of the above Signup and view all the answers

During gait cycle, what is the ideal external rotation of the foot for smooth rollover from heel to toe?

3° to 5° Signup and view all the answers

What is the ideal base of support width during dynamic alignment of a Transtibial (TT) prosthesis?

5-10 cm Signup and view all the answers

During bench alignment of a Transfemoral prosthesis, what is the purpose of adjusting the socket with the hip in 2° to 5° of adduction?

To accommodate the length of femur and strength of hip muscles Signup and view all the answers

What is the ideal socket position during bench alignment of a Transtibial (TT) prosthesis, as viewed from the side?

Socket midpoint falls over the midpoint of the foot bolt Signup and view all the answers

What is the ideal characteristic of the toe clearance during dynamic alignment of a Transtibial (TT) prosthesis?

Toe clearance is adequate in the swing phase Signup and view all the answers

What is the ideal characteristic of the hip alignment during dynamic alignment of a Transfemoral prosthesis?

Hips are level and even Signup and view all the answers

What is the purpose of aligning the femur under the hip joint in a transfemoral prosthesis?

To put a mild stretch on gluteus medius Signup and view all the answers

What is the estimated center of the hip joint in relation to the ischial tuberosity?

2.5 cm lateral to the ischial tuberosity Signup and view all the answers

Why is the knee joint externally rotated by 5° in a transfemoral prosthesis?

To facilitate ease of swing phase Signup and view all the answers

What is the purpose of adjusting the socket with the hip in 5° flexion?

To mildly stretch the hip extensor muscles Signup and view all the answers

What is the result if the line from the greater trochanter to the ankle passes through the knee joint?

No moment is produced by body weight Signup and view all the answers

What is the purpose of using an offset plate in the hip?

To make flexion accommodations during static alignment Signup and view all the answers

What is the result of placing the prosthetic knee and ankle lateral to the center of the hip joint in individuals with shorter stumps and weak muscle control?

Increased energy expenditure during prosthetic single-limb stance Signup and view all the answers

What is the purpose of using a pyramid in prosthetic alignment?

To make angular changes to encourage weight shifting in both the coronal and sagittal planes Signup and view all the answers

Study Notes

Transtibial Prosthesis Alignment

Bench alignment:
- Side view (Sagittal plane):
  - Plumb line passes through anatomic knee center and junction point of posterior third and anterior 2/3 of foot
  - Socket aligned with knee flexed 5° to 10° to facilitate heel strike and place quadriceps on stretch
  - Foot position: center of heel and big toe aligned along line bisecting socket from anterior view
- Anterior view (Coronal plane):
  - Plumb line passes through mid-patella and center of heel
  - Socket placed in 2° to 5° of varus (adduction) to protect head of fibula and encourage lateral shift at midstance
  - Foot externally rotated by 3° to 5° for smooth rollover from heel to toe
Dynamic alignment (gait within parallel bars):
- Smooth rollover from heel to toe with good control of knee
- Consistent base of support width: 5-10 cm
- Toe clearance in swing phase, comfortable weight bearing on prosthesis, and level hips
- Equal and adequate step length

Transfemoral Prosthesis Alignment

Bench alignment:
- Aims for stability in double-limb stance, adequate lateral shift in single-limb stance, and narrow base of support (5 cm)
- Anterior view:
  - Socket adjusted with hip in 2° to 5° of adduction according to length of femur and strength of hip muscles
Dynamic alignment:
- Walking in a safe environment, often with parallel bars, to identify and correct gait deviations for more efficient gait technique

Prosthetic Gait

Transtibial:
- Initial contact by lateral border of heel, knee flexed by 20° at initial contact
- Loading response: medial aspect of forefoot then contacts ground during stance
- Medial border of foot parallel to line of progression
- During midstance, dorsiflexion steadily increases as knee moves over foot
- Pre-swing: heel comes off ground when swing foot passes anterior to stance limb
- Prosthesis rolls forward over toe and lifts off ground
- Sufficient ground clearance

Gait Deviations

Excessive inversion or eversion of foot: misalignment of prosthesis
Excessive knee flexion:
- Foot too far posterior
- Too dorsiflexed
- Heel too rigid
Insufficient knee flexion:
- Knee fully extended at heel strike
- Heel too soft
- Foot positioned too far anteriorly
Excessive varus: socket too far inset
Foot too outset: excessive ex-rotation (heel moves inward)
Socket excessively adducted

Additional Points

Center of hip (COH) estimated as 2.5 cm lateral to ischial tuberosity
For long stump and good muscle control, prosthetic knee and ankle placed directly below COH for minimal lateral shift at midstance
For shorter stump and weak muscle control, knee and ankle placed lateral to COH to increase base of support
Knee joint externally rotated by 5° for ease of swing phase

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Description

This quiz covers the dynamic alignment of transtibial prosthetics during the gait cycle, including bench alignment and sagittal plane considerations. Learn about the importance of proper alignment for optimal gait and knee function.