Case of the week: 12-5-2005

Supplied by Mark Geil, Department of Kinesiology and Health

History

Cast 6/16/04 for AFOs to prevent toe walking, pes planovalgus, and spasticity. Received bilateral articulated AFOs with plantarflexion stop, valgus control trimlines, and ankle cross-strap on 7/1/04.

Patient was evaluated for gross motor skills using the Peabody Gross Motor Development Skills Assessment.
Able to demonstrate skills #61-70 (12-14 months level). Patient could not demonstrate skills 71, 73, and 76 nor 79. (Refused and protested stairs. #79 tandem stance not accomplished.) Given patient’s reluctance to the evaluations, she is estimated at best to be in the 15-17 month stage of motor development. She exhibits spastic diplegia that has been aided by AFOs and Botox injections. She also appears to possibly have some visual deficits as she holds her head to one side and studies objects up close. Mother was told the patient is too young for visual testing.

Short –term goals (4-6 weeks): patient will demonstrate the ability to climb stairs with PT’s support utilizing one rail. Patient will demonstrate unsupported stance on one foot enabling her to kick a ball.
Long-term goals (7-12 weeks): Patient will demonstrate ability to walk on balance beam with one hand supported. Patient will demonstrate 2-legged jumping.

In September short-term goal #1 partially met.
 

Kinematic Analysis

Pelvic Kinematics

• Sagittal plane (pelvic tilt): With the AFO condition, there was an increased anterior pelvic tilt of about 7 degrees during opposite toe off and an increased posterior pelvic tilt of about 7 degrees during toe off on the left side.
• Frontal plane (pelvic obliquity): The right side of the pelvis was higher than the left side throughout the cycle in both conditions.
• Transverse plane (pelvic rotation): In both conditions, the left side of the pelvis was more anterior than the right, represented on the chart as an ‘internal rotation’ on the left and ‘external rotation’ on the right. The overall range of excursion, however, approximated normal ranges under both conditions.

• Hip: The right side of barefoot condition was biased into flexion. With the AFOs, the two sides were almost equal for most of the cycle and closed to the norm.
• Knee:  Similar to the hip, the right side of the barefoot condition was increased in knee flexion. With AFOs, the two sides were almost equal for most of the cycle except for increased knee flexion on the right side during swing. “Jump knee” pattern observed, with knee flexion at initial contact followed by knee extension and, in some cases, hyperextension, noted more on the left than right side.
• Ankle: Barefoot, there was a significant bilateral reduction of plantarflexion, before, after, and immediately after toe off. With AFO, there were significantly improved for both sides but there still no plantarflexion exhibited during toe off.

• Upper extremity exhibited a greater high guard position in the barefoot condition.

2-D Kinematic Analysis and Comparison

Dartfish can be used to calculate temporal and spatial parameters based on a superimposed clock and distances calibrated to a known distance in a separate video clip.

Barefoot temporal and spatial parameters were calculated based on this video:
 

• Right step length: 0.22 m
• Stride length: 0.51 m
• Mean walking speed:

The rhythmic changes in temporal and spatial parameters can be visualized when videos from each condition are superimposed. In addition, the changes in loading response due to the shoes and orthoses are evident.
 

Jump Knee Focus

Points for discussion:

• Does the jump knee pattern originate from the knee joint or the ankle joint?
• One possible scenario:
• The ankle is plantarflexed at initial contact, and the external dorsiflexor moment results in dorsiflexion to a point.
• The ankle reaches a static or dynamic limit to dorsiflexion, at which point the foot/ankle complex acts as a rigid body.
• The external dorsiflexor moment now produces knee extension as the heel drops toward the ground and, in some trials, hyperextension, as stance phase progresses.
• What considerations should one use when planning Botox injections in the case of recurvatum. As hyperextension increases, the external extensor moment arm increases.
• How does Botox affect the muscles that might play a role in protecting the knee joint?
• In general, the AFOs reduce mean walking speed slightly. Generally a reduction in velocity is a negative outcome. In this case, is the improvement afforded by the AFOs worth a reduction in velocity?
• What’s the best way to define toe-off in the presence of foot drag? Reduction in ground reaction force? Kinematics of ankle or heel marker?
• How well does the quality of data obtained from simple 2-D analysis compare to full 3-D analysis in this case?

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