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Össur Pro-Flex Introductory Course

Thank you for taking the first step to completing your Pro-Flex® Product Certification, approved for 5.5 CEUs.


Step 1

Complete the Online Course

- Review the following online course and click the button below to complete the quiz.

- Upon clicking Submit, your answers will be submitted to ABC for the approval of 1.5 CEUs.

Step 2

Complete the Onsite Certification

- After completing the quiz, you will be added to the waitlist for the Pro-Flex Product Certification (approved for 4 CEUs), which will be conducted onsite at your location.

- Please wait for your Össur Area Manager to contact you to schedule the onsite certification course, pending availability.

Please note: You are required to identify a qualified and approved patient prior to scheduling the onsite course.

- Following completion of the onsite portion, you will be fully Certified to fit Pro-Flex and an additional 4 CEUs will be sent to ABC for approval.


The Pro-Flex foot with pivot technology is the new premium foot from the makers of FLEX-FOOT. It is the first mechanical foot to use multiple carbon fiber levers connected through related pivots. The Pro-Flex foot is part of Össur’s Dynamic Solutions family of products, which offers unparalleled performance for the prosthetic user. As with the current industry gold standard, the Vari-Flex, Pro-Flex performance is supported by medical evidence.

Less Load, More Dynamics

Knee osteoarthritis (OA) is a common comorbidity in the amputee population. Individuals with unilateral limb-loss experience a higher incidence of OA in the joints on their sound side, compared with joints in their prosthetic side and the joints of able-bodied individuals1,2. Osteoarthritis occurring in the sound-limb knee joint is 17 times higher than in age-matched non-amputees3 and knee pain is twice as common3.

Imaging studies have confirmed the increased prevalence of degenerative changes in the sound-limb knee4,5. This can be attributed to amputees spending more time on their sound limb than the prosthetic limb during walking6,7,8. As a result, temporal parameters of gait are asymmetrical and the loading on the sound limb is greater9,10.

Against a backdrop of rising levels of knee OA among the general population, and higher risks for those with limb loss in particular, it is important to scrutinize prosthetic solutions. Technology that appreciably reduces the wear and tear on a person’s body is very important. It has the potential to improve an individual’s quality of life and reduce long-term healthcare costs.

The choice of prosthetic foot can influence impact levels on the sound side limb. More specifically, the Flex-Foot® design has been shown to reduce ground reaction forces (GRF) on the sound side.11 Standard foot designs, on the other hand, have been reported to significantly increase both impact levels and knee instability12. The new Pro-Flex foot with pivot technology exhibits exceptional behavior in terms of impact reduction and rollover. Its smooth and consistent progression towards terminal stance terminates with a powerful push-off. This unprecedented mechanical push-off power means the body’s center of mass is controlled13 on the prosthetic side at the time of stepping forward onto the sound side. The result is a smoother, more symmetrical gait and reduced impact on the sound side.14,15,16 These are two key factors in reducing the risk of knee OA.

What is Pro-Flex?

In the past, carbon fiber foot designs had one drawback: the carbon fiber needed to be soft in order to absorb shock and allow the user to progress through the stance phase of gait. However, in order to give the prosthetic user an appropriate push-off moment in late stance, the same carbon fiber needed to be rigid. Until now, you couldn’t have it both ways. The design of the new Pro-Flex foot gives the user the benefit of shock absorption and energy storage in early stance, easy progression through midstance, and a rigid toe lever in late stance.

The Pro-Flex foot with pivot technology consists of three carbon fiber levers connected through pivots. This design ensures that the Pro-Flex acts as a true ankle joint. The main pivot acts as the center of rotation for the ankle. The upper supporting pivot and lower rear pivot allow movement of the ankle and foot throughout the midstance phase of gait. The bottom, middle, and top levers produce a new method to use the dynamic response of carbon fiber. They allow the toe lever to progressively stiffen as the user advances through the late stance phase of gait.

In addition, the shape of the bottom carbon lever is narrower through the midfoot and wider at the metatarsal heads, mimicking the normal shape of the human foot. It has a sandal toe feature and a split toe design. The bottom carbon lever also has a full, effective toe length. When compared to Talux, the Pro-Flex foot is 12mm longer and when compared to Vari-Flex it is 30mm longer. This full, effective toe lever is an important contributor to the mechanical push-off power of this new foot.

Last but not least, the Pro-Flex foot also has a brand new foot cover. This foot cover has many features to ensure that the foot will fit well in the shoe, be easy to maintain, and contribute to the outstanding function of the Pro-Flex foot. When the foot is inserted into the foot cover, the toes pinch together to hold sandals or flip-flops in place. The cover is resistant to soiling, staining, and water. Like the foot, the cover is anatomically shaped, with a defined medial arch to accommodate the insole of a shoe. Finally, the foot cover also has a higher coefficient of friction. This means that the foot will be slip-resistant when the user chooses to walk barefoot.


What are the Clinical Benefits?

Decades ago, the SACH foot was the standard of care. However, consumers expect technology and performance to change over time. In the mid-1990’s Össur introduced FLEX FOOT technology using a J-shaped design and the use of a new material: carbon fiber. This revolutionized prosthetic foot performance. Today, with the introduction of the Pro-Flex with pivot technology, we can confidently make new claims of enhanced performance. First, it offers greater ankle ROM. This includes both dorsiflexion and plantarflexion, and totals nearly 28 degrees. Second, it offers greater ankle power at the end of the stance phase of gait. Lastly, the center of pressure progression is closer to anatomical.


ankle ROM in stance [deg]

Level ground 27.7* (5.2) 15.2* (1.9)
Ramp descent 25.4* (5.2) 12.4 (1.7)
Ramp ascent 25.8* (5.3) 14.0 (1.8)

An independent study shows evidence of these claims regarding the Pro-Flex foot17. Eleven transtibial subjects were fitted with a conventional energy-storing foot, the Vari-Flex, two weeks prior to testing. The subjects were then fitted with the prototype foot, the Pro-Flex. They walked 1.5 km to accommodate to the new foot, and then were tested again. The results indicate a significant increase in the amount of ankle ROM (82%) and ankle power (93%) in the Pro-Flex foot. The results also included measurement of sound limb loading via vertical ground reaction forces. The study found that the sound limb was loaded an average of 11% less during the gait cycle with the Pro-Flex foot. This finding was also statistically significant within the study. Additionally, there was a reduction in peak external adduction moment (EAM) of 15% on the sound limb when using the Pro-Flex foot. The external adduction moment is a measure of the varus force on the knee during gait.

As mentioned earlier, these last numbers are vitally important to the end user’s functionality, because they relate directly to the development of knee osteoarthritis18.

Össur also measured the center of pressure (COP) progression in the Pro-Flex foot. The center of pressure progression is the sum of the pressures of the foot against the ground, expressed as a single point. The points move forward as the individual progresses through the stance phase of gait. Typically, the COP begins in the center of the heel, progresses forward and laterally to the midfoot, medially across the metatarsal heads, and exits through the great toe. Testing revealed that the COP progression of the Pro-Flex was closer to anatomical than a Vari-Flex foot.

Earlier, we discussed three core claims that Össur can make regarding the new Pro-Flex with pivot technology. These three core claims form the basis of our last two claims. By increasing ankle ROM, increasing ankle power, and normalizing the center of pressure progression we can effectively reduce the impact of loading on the sound side and improve a patient’s satisfaction with their prosthetic foot.

Who will benefit from Pro-Flex?

Pro-Flex foot with pivot technology is indicated for the Medicare Functional Classification Level 3 (K3) ambulator at the transtibial and transfemoral level. Though it demonstrates superior performance on level ground, ramps, and stairs, the Pro-Flex foot is not a high-impact foot. Low to moderate activity levels are appropriate. Individuals who want to improve their gait symmetry will benefit from the Pro-Flex foot. The added ROM and power enables a longer and easier sound side step. Individuals who want to limit their sound side knee pain or prevent future comorbidities will also benefit from the Pro-Flex foot. The evidence supports reduced loading on the sound limb. Lastly, individuals who may want to mitigate internal socket pressures may benefit from the Pro-Flex foot. The significantly increased ROM demonstrated on inclines and declines indicates improved compliance to the ground, which has been shown to mitigate socket pressures in other energy-storing prosthetic feet19.

Reimbursement and Billing

Össur suggests the following code for Pro-Flex, as no code(s) in the current HCPCS Code Set describe it:

L5999 All lower limb extremity prostheses, foot, 2 or more energy-storing and returning flexible carbon fiber levers connected by 2 or more rotating pivot points producing mechanically-powered push off and significantly increased range of motion.
For claims using L5999 the prosthetic supplier is responsible for selecting the appropriate fee for that L-Code.

You may contact Össur Customer Service or your local Area Manager for additional information on pricing and reimbursement.


The Pro-Flex with pivot technology by Össur is the step in the right direction, providing Less Load and More Dynamics. Its design combines an incredible 28 degree ankle range of motion, significantly greater energy return than a conventional carbon fiber foot, and an improved mechanically powered push-off. These features reduce peak impact forces and external adduction moment on the sound limb by 15% and 11% respectively. Multiply those advantages over a lifetime of steps and the potential health benefits become clear: by decreasing the sound side limb load and enhancing foot dynamics, the impact on the financial and human cost of osteoarthritis can be reduced.

Next Step

Take the Quiz

To finish the online course, and earn 1.5 CEUs, please click the button below to take the Course Quiz.



1. Kulkarni J, Adams J, Thomas E, Silman A. Association between amputation, arthritis and osteopenia in British male war veterans with major lower limb amputations. Clin. Rehabil., 12 (4) (1998), pp. 348–353

2. Nolan L, Wit A, Dudzinski K, Lees A, Lake M, Wychowanksi M. Adjustments in gait symmetry with walking speed in trans-femoral and trans-tibial amputees. Gait Posture.2003;17(2):142–51 prosthetic knee. Arch Phys Med Rehabil 2007;88:207-17.

3. Struyf, Pieter A., et al. "The prevalence of osteoarthritis of the intact hip and knee among traumatic leg amputees." Archives of physical medicine and rehabilitation 90.3 (2009): 440-446.

4. Norvell DC, Czerniecki JM, Reiber GE, Maynard C, Pecoraro JA, Weiss NS. The prevalence of knee pain and symptomatic knee osteoarthritis among veteran traumatic amputees and nonamputees. Arch Phys Med Rehabil 2005;86(3):487–93.

5. Lemaire ED, Fisher FR. Osteoarthritis elderly amputee gait. Arch Phys Med Rehabil 1994;75(10):1094–9.

6. Breakey J. Gait of unilateral trans-tibial amputees. Orthot Prosthet. 1976;30:17–24.

7. Murray MP, Mollinger LA, Sepic SB, Gardner GM, Linder MT. Gait patterns in above-knee amputee patients: Hydraulic swing control vs constant-friction knee components. Arch Phys Med Rehabil. 1983;64(8):339–45.

8. Engsberg JR, Lee AG, Tedford KG, Harder JA. Normative ground reaction force data for able-bodied and below knee amputee children during walking. J Pediatr Orthop. 1993;13(2):169–73.

9. Suzuki K. Force plate study on the artificial limb gait. J Jpn Orthop Assoc. 1972;46:503–16.

10. Engsberg JR, Lee AG, Patterson JL, Harder JA. External loading comparisons between able-bodied and below knee amputee children during walking. Arch Phys Med Rehabil. 1991;72(9):657–61

11. Snyder, R.D., et al., The effect of five prosthetic feet on the gait and loading of the sound limb in dysvascular below-knee amputees. J Rehabil Res Dev, 1995. 32(4): p. 309-15.

12. Lehmann JF, Price R, Boswell-Bessette S, Dralle A, Questad K. Comprehensive analysis of dynamic elastic response feet: Seattle Ankle/Lite Foot versus SACH foot. Archives of Physical Medicine & Rehabilitation 1993;74(8):853-61.

13. Powers, Christopher M., et al. "Influence of prosthetic foot design on sound limb loading in adults with unilateral below-knee amputations." Archives of physical medicine and rehabilitation 75.7 (1994): 825-829.

14. Segal, Ava D., et al. "The effects of a controlled energy storage and return prototype prosthetic foot on transtibial amputee ambulation." Human movement science 31.4 (2012): 918-931.

15. Kuo, Arthur D. "The six determinants of gait and the inverted pendulum analogy: A dynamic walking perspective." Human movement science 26.4 (2007): 617-656.

16. Kuo, Arthur D., J. Maxwell Donelan, and Andy Ruina. "Energetic consequences of walking like an inverted pendulum: step-to-step transitions." Exercise and sport sciences reviews 33.2 (2005): 88-97

17. Heitzmann DWW. et al; A novel prosthetic foot leads to increased ankle power and reduced sound side loads in trans-tibial amputees; Abstract, Oral Presentation at the AOPA National Assembly San Antonio, TX, USA, October 7-10, 2015; E-mail:

18. Morgenroth, David C., et al. "The effect of prosthetic foot push-off on mechanical loading associated with knee osteoarthritis in lower extremity amputees." Gait & posture 34.4 (2011): 502-507.

19. Wolf, S.I., et al., Pressure characteristics at the stump-socket interface in transtibial amputees using an adaptive prosthetic foot, J. clin. biomech. (2009), doi:10.1016/j.clinbiomech.2009.08.007.