Microprocessor Knee Mechanisms and Advanced Foot/Ankle Systems Gary M. Berke MS, CP, FAAOP Adjunct Clinical Assistant Professor, Department of Orthopaedic Surgery, Stanford University Private Practice Prosthetist State of the Art Technology:

Disclosures Ossur Americas, Advisory Board Member

Objective ❖ Understand the current State of the Science as it pertains to Clinical Care and the use of Higher Technology Componentry

Microprocessor Knees Academy State of the Science on MPK’s a. 6 Questions considered b. Systematic Literature Review (up to 2009) 1. Empirical Evidence Statements c. Basic Literature from d. Conference Results

Microprocessor Knees All Microprocessor Knees are NOT the same!! a. Swing only b. Swing and Stance

Systematic Literature Review Sawers and Hafner up to 2010 (further review to 2012) A search of biomedical databases identified 241 publications. Twenty-seven met the inclusion/exclusion criteria and were reviewed for methodological quality and content. These studies were ranked in to three groups.

Empirical Evidence Statements based on methodological quality, multiple independent studies and consistentcy of results The EESs were grouped into nine outcome topics; 1) Metabolic Energy Expenditure 2) Activity 3) Cognitive Demand 4) Gait Mechanics 5) Environmental Obstacle Negotiation 6) Safety 7) Preference and Satisfaction 8) Economics 9) Health and Quality of Life

Empirical Evidence Statements ❖ There is Moderate Evidence comparing MPK and NMPK that: ❖ Metabolic Energy Expenditure is equivalent ❖ There is an increase in self-reported mobility ❖ There is equivalent ability to ambulate while performing secondary cognitive task ❖ But a perception of a decrease in cognitive demand ❖ There is an increase in subject reported confidence

Empirical Evidence Statements ❖ There is Moderate Evidence comparing MPK and NMPK that : ❖ There is equivalent self reported general health ❖ There is an Increase in self reported well-being ❖ There is an Increase QALY scores ❖ MPK results in increased prosthesis acquisition costs ❖ Equivalent costs of prosthetic rehabilitation

Empirical Evidence Statements ❖ There is LOW Evidence when comparing MPK and NMPK that : ❖ That there is any influence on Gait Mechanics ❖ There is any effect of walking speed on uneven ground and stair descent. ❖ There is any subject reported preference and satisfaction. ❖ Decreased number of self-reported stumbles and falls

SSC Group then got involved….

Consensus Statements There appears to be significant differences among the various types of microprocessor knees. Classifying knees in to one category, simply because they utilize a microprocessor, is “inaccurate and inappropriate”.

Consensus Statements There appears to be evidence for improved safety with one type of swing and stance MPK. While we all maintain very strong beliefs in this area, the literature to date does not supply ample evidence to address who is an appropriate candidate for an MPK. Research should focus on the potential benefits for the High K2 level functioning patient

Consensus Statements ❖ Expected clinical outcomes (such as increased use, improved gait, improved confidence, and decreased falls) are not well demonstrated in current studies. ❖ Measures that can evaluate daily living activities and cognitive burden rather than typical laboratory measures would be better suited for this unique population.

Consensus Statements Candidacy for MPK should be based on Medical comorbidities, functional history, goals, access to providers, fall history, occupation, and avocation. Training, Physical Therapy, Accommodation time, and Acclimation can impact long term outcomes.

Consensus Statements There is sound reasoning as to why limiting MPK prescription to only the K3 level ambulator is inappropriate. Clinical and expert opinion is there that there is an improvement in safety with use of an MPK (as demonstrated in the poly-trauma or bilateral patient)

In the end ❖ Microprocessor knees: ❖ Do NOT improve energy consumption, improve gait pattern, reduce cognitive demand, general health ❖ Do appear to improve safety, improve patient perception of cognitive loading and confidence.

Prosthetic Foot and Ankle Mechanism ❖ Much less evidence as to the functional benefit of the technologically advanced feet and ankles ❖ 23 articles were reviewed, 8 were not peer-reviewed, many were biased and the majority were of low quality. ❖

Three Groups ❖ Powered Ankle- BioM ❖ Adaptive Ankle- Proprio ❖ Hydraulic Ankle- Eschelon All studies compare these to Energy Storage (ESR) feet!!!

Prosthetic Foot and Ankle Mechanism Anatomical improved energy consumption improved use on stairs Manufacturer Claims

Prosthetic Foot and Ankle Mechanism Reduces the risk of trips and falls and enhances safety and gait quality. Enables users to focus on their surroundings, instead of the walking terrain, offering a high degree of ground compliance, on all kinds of surfaces. Reduces strain on knees, hips and back. Enhances stability, efficiency and comfort on inclines, declines and stairs. Maintains symmetry and alignment while changing shoes. Manufacturer Claims

Empirical Evidence Statements ❖ Contralateral knee mechanics (External Adductor Moments and knee arthritis) (2) ❖ There is an effect with powered feet but not statically significant ❖ Contralateral Compensatory Activity (2 ) ❖ One study showed significant compensatory activity the other showed none ❖ Effect on Stairs and Inclines (4) ❖ All studies show improvement on incline assent. Improved plantar flexion power and range of motion but still no significant clinical impact demonstrated. ❖ Improved toe clearance, less whole body angular momentum but no improvement in safety

Empirical Evidence Statements  Uneven ground ambulation (1) ❖ Improved proximal joint kinematics (compared to ESR) ❖ Effect on Socket/ Limb Pressures (3 studies) ❖ Improved, especially effective going down slopes ❖ Gait Speed increased in most studies ❖ the reason appears to be consistent with a smoother roll over than due to push off.

Conclusion ❖ Not enough information to draw any conclusions on the function and efficacy of advanced prosthetic feet. ❖ It is unclear if the additional cost justifies the current functional gains on levels and stairs or activities of living.

Thank you!!