8. Foot and Ankle MCQs

On a standing full-length AP radiograph of the lower extremities, the mechanical axis line is drawn from the center of the femoral head to the center of the ankle talus. If this line passes lateral to the center of the knee joint, what deformity is present?

During the normal gait cycle, the 'second rocker' (ankle rocker) is defined by tibial progression over the plantigrade foot during mid-stance. Which muscle group predominantly controls this motion?

During the initial contact (heel strike) phase of a normal gait cycle, what is the position of the ground reaction force (GRF) vector relative to the anatomic centers of the hip, knee, and ankle joints?

A 12-year-old with spastic diplegic cerebral palsy presents with progressive "crouch gait" characterized by excessive hip and knee flexion and ankle dorsiflexion during stance. Which of the following previous iatrogenic interventions is the most likely primary contributor to this gait pattern?

During the second rocker (ankle rocker) phase of normal gait, which muscle group acts eccentrically to control the forward progression of the tibia over the foot?

A 12-year-old child with spastic diplegic cerebral palsy presents with a profound crouch gait. Physical exam reveals severe flexion contractures of the knees. Over-lengthening of which muscle group during prior multi-level surgeries is the most common iatrogenic cause of this gait pattern?

A 12-year-old with spastic diplegic cerebral palsy develops a worsening crouch gait following bilateral Achilles tendon lengthenings. Weakness or over-lengthening of which muscle group is the primary biomechanical cause of this resultant gait pattern?

During the loading response phase of a normal gait cycle, what is the position of the ground reaction force (GRF) vector relative to the hip, knee, and ankle joints?

A 14-year-old boy with spastic diplegic cerebral palsy presents with an increasingly severe crouch gait. He underwent isolated bilateral Achilles tendon lengthenings at age 6 for toe-walking. Which of the following best explains the pathophysiology of his current gait abnormality?

You evaluate a 45-year-old with a post-traumatic varus deformity. On a full-length standing radiograph, the mechanical axis deviation (MAD) is medial. The mechanical lateral distal femoral angle (mLDFA) is 87 degrees, and the medial proximal tibial angle (MPTA) is 80 degrees.

Based on these measurements, what is the primary source of the deformity?

During clinical gait analysis, a patient exhibits a 'foot slap' immediately after initial contact, transitioning into the loading response. Weakness of which of the following muscle groups is primarily responsible for this finding?

At the exact moment of initial contact (heel strike) during normal walking gait, where does the ground reaction force (GRF) vector typically pass relative to the ankle and knee joints?

In a normally aligned lower extremity, the mechanical axis (a line drawn from the center of the femoral head to the center of the ankle mortise) passes through the knee joint at which location?

A 12-year-old with spastic diplegic cerebral palsy presents with a severe crouch gait. Kinematically, this gait pattern is characterized by which combination of joint positions during the stance phase?

During normal human walking, what is the position of the ground reaction force (GRF) vector relative to the hip, knee, and ankle joints immediately at initial contact (heel strike)?

A 12-year-old patient with spastic diplegic cerebral palsy presents with a progressive crouch gait following bilateral Achilles tendon lengthening procedures performed two years ago. Which of the following biomechanical abnormalities is the primary cause of this patient's current gait pattern?

During the stance phase of normal gait, what is the coupled motion of the subtalar joint and the tibia from initial contact to midstance?