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JPO Journal of Prosthetics and Orthotics: July 2004 - Volume 16 - Issue 3 - p 76-77
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  1. Read the article on pages 72–75.
  2. Complete the examination.
  3. Submit your completed examination to the AAOP per the directions on the next page.


The following questions require short answers only; you do not have to use complete sentences. All questions refer to the article “Measurement of Knee Center Alignment Trends in a National Sample of Established Users of the Otto Bock C-Leg Microprocessor-Controlled Knee Unit” by Laura L. Willingham, BS, Noelle C. Buell, MSPT, Kate J. Allyn, LCPO, CPed, Brian J. Hafner, PhD, and Douglas G. Smith, MD.


Please allow 2–4 weeks for processing.

1. Prosthetic knee components vary in (list three aspects)_____________, ____________________________, and ______________.

2. True or False?

Traditionally recommended alignment of the position of the knee center is anterior to a vertical reference line.

3. The recommended alignment for the Otto Bock C-Leg knee unit is:

a. 0 to 5 mm posterior to a vertical reference line.

b. 1 to 5 mm anterior to a vertical reference line.

c. 0 to 5 mm anterior to a vertical reference line.

4. True or False?

The more posterior the knee center is placed, the greater the range of stability the amputee has before the knee will buckle.

5. Three commonly-used reference lines to assess alignment stability in the sagittal plane are:

a. ___________________________________________________________

b. ___________________________________________________________

c. ___________________________________________________________

6. The Laser Assisted Static Alignment Reference (LASAR Posture device) manual defines two reference lines which are:

a. ___________________________________________________________

b. ___________________________________________________________

7. According to Winter, the C of G is:

a. totally independent of the velocity and acceleration of the total body and its segments.

b. the net location of its center of mass in the vertical direction.

c. both a and b.

8. The rate of walking that is voluntarily assumed is defined as the _____________________.

9. Poor mechanical alignment has been noted to exacerbate _____________________.

10. The primary physical advantage to having the knee center anterior to the reference line is that:

a. it decreases stance flexion.

b. it increases stance flexion.

c. it increases the range of stability.

Complete the JPO Self-Assessment Examination on the previous page and score a minimum of 75 percent to earn two PCE credits. Send the completed examination and payment in U.S. currency ($20/AAOP members, $40/nonmembers) to: AAOP, Dept. 937, Alexandria, VA 22334-0937. The examination must be received by the AAOP within 3 years of the publication date for credit to be awarded.

Name __________________________________________________________________

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© 2004 American Academy of Orthotists & Prosthetists