Niagara Foot. Dynamic Performance at Every Step

Transcription

1 Niagara Foot Dynamic Performance at Every Step 1

2 Table of Contents Concept 3 Biomechanics 3 Tech Specs.4 Static/Bench Alignment..5 Dynamic Alignment..6 Niagara Foot Modifications 7 Assembly Instructions..10 Warranty

3 Concept From concept to reality! The Niagara Foot is a dynamic energy-storing prosthetic foot, which was developed in collaboration with various research institutions and DuPont Engineering Polymers Division. The foot is made out Hytrel, a state of the art engineering grade polymer. Hytrel produces superior function, ensures high energy efficiency, and extreme durability. Additionally, the smooth action of the foot reduces the biomechanical forces acting on the residual limb. The Niagara Foot is maintenance free, water resistant and can be dynamically modified by the prosthetist or technician, in order to optimize the gait cycle in accordance with the weight and activity level of the amputee. It is an excellent all round foot, suitable for K2 and K3 users. It was extensively tested in numerous field tests and according to ISO standard on the P5-100 kg protocol. Biomechanics The design has been refined and field tested by an international team of researchers, including Dr. Tim Bryant (Human Mobility Research Centre, Queen's University and Kingston General Hospital, Canada) and Ing. Heinz Trebbin (Universidad Don Bosco, El Salvador). The Niagara Foot is comprised of a number of sections. The design concept was to develop an adjustable dynamic device that, if desired, could be cosmetically enhanced using standard cosmetic foot shells. The foot has five main sections consisting of the Platform, Dynamic C Coil, Horns, Heel Lever and the Forefoot Lever (see image). The way it functions is at heel strike, the platform starts to open and flex upwards. At the same time it will open the gap that is between the platform and the horns. That motion relies on having the proper flexibility in the Dynamic C Coil. 3

4 As the foot moves into mid-stance and the patient moves forward the foot is placed in neutral. There is now floor contact at both the heel and the forefoot. This causes the gap to close making the system stiffer but maintaining some flexibility. At this stage the horns and platform come in contact which helps to transfer energy to the Forefoot Lever. In the toe off phase of the cycle the Forefoot Lever is loaded which transfers energy into the follow through phase of the cycle. Tech Specs Specifications Activity Level = K2 - K3 Weight Limit = 215 lbs Size Adjustment cm Unilateral - L or R Build height = 10 cm Keel Weight / Pyramid & Titanium Bolt = 459 grams Foot Bolt Torque = 30 Nm Pre-Fab Cosmetic Foot Shell = L/R Custom Keel / Cosmetic Foot = L/R Considerations The Niagara Foot includes an installed Stainless Steel Pyramid Adapter / Foot Bolt. Accurate torque settings require documentation! If the Stainless Steel Pyramid Adapter is not used the fabricator must implement anti rotation pins between the foot adapter and the Niagara Foot. This adaptation voids any and all warranties and or guarantees provided with the Adaptor. 4

5 Static/Bench Alignment Initial bench alignment would place the weight line between the markings indicated. The weight line seldom falls proximal (posterior) to the centerline of the bolt connection to the pyramid adapter. Trochanter, Knee, Ankle (TKA) Alignment must be considered in Trans-Femoral(T/F) applications. The weight line seldom falls distal (anterior) to the centerline of the Niagara Foot. Remember there are exceptions to every rule! Practice your standard bench alignment techniques. Set your static alignment slightly anterior (distal) to your standard bench alignment protocol. 5

6 Dynamic Alignment If your patient has been using any other foot, the Niagara Foot may feel completely different to them. Most clients require time to adjust to the additional mobility the Niagara Foot provides. Adjustments along with a learning curve will be required. A controlled gait specific learning period would be beneficial. Once the practitioner realizes the effective dynamic diversification available with the Niagara Foot their prosthetic management capability will improve. Left & Right great toe profiles can be implemented to provide custom gait toe offs. The Hytrel polymer developed by DuPont, is easily machined. Note the reduction steps x 5 in the Forefoot Lever. (as viewed on the image left) The length of the Niagara Foot can be shortened as required. Consider heel and forefoot reductions for smaller foot sizes. Extension beyond 28 cm are at the practitioner's discretion. 6

7 Niagara Foot Modifications The Niagara Foot's recognized weight limit for K2/K3 ambulators is 220lbs (100 kg). Heavier clients at other K levels should be managed at the discretion of the Prosthetist. The heel, Dynamic C Coil and Forefoot Levers throughout the Niagara Foot can be softened by reducing the Hytrel thicknesses in the Niagara Foot. This can be accomplished by using a wood rasp and or staged abrasive removal of the thickness indicators. Final finish must be smooth and notch free. The Anterior-Posterior(A-P) positioning of the energy return foot may affect the speed with which the different stages are reached within the gait cycle. Shift the foot posterior or socket anterior if the mid stance position is reached too early. Shift the foot anterior or socket posterior if the heel-to-toe movement is too rapid. If the heel is too stiff the patient may experience toe slap, minimum energy return, loss of prosthesis control and or knee instability. Remedies include moving the socket posterior, the foot anterior or softening the Heel Levers stiffness. Reduce the heel stiffness by removing Hytrel thickness from the heel section. There are 4 levels of reduction adjustment. Reductions can be accomplished by using a wood rasp and/or mechanically using your shaft carver. Final finish must be smooth and notch free. If the client feels that the toe is too stiff, dorsiflex the foot or move the foot posterior. If this does not give desired relief you may also soften the forefoot lever. 7

8 Reduce the forefoot lever stiffness by removing Hytrel thickness from the forefoot section. There are 5 levels of reduction adjustment. Remove one level at a time. Reductions can be accomplished by using a rough file and/or mechanically using your shaft carver. Final finish must be smooth and completely notch free. Reduce the Dynamic C section stiffness by removing Hytrel thickness from the Dynamic C Profile section. There are 4 levels of reduction adjustment. Reductions can be accomplished by using a rough file and/or mechanically using your shaft carver. Final finish must be smooth and in particular notch free. It is not recommended that the original staged thickness profiles be exceeded. All reductions performed must consider reasonable weight and activity adjustments implemented by the practitioner. Take your time, you can always take more material off, you can't replace it! The length of the Niagara Foot can be shortened as required. Consider heel and forefoot reductions for smaller foot sizes. While Dupont's Hytrel polymer is not overly notch sensitive it is important to smooth out all modifications performed on the Niagara Foot. * Removal beyond the thickness indicators voids all warranties on the foot. Before the foot is dispensed place a very small amount of lithium grease between the horns and the platform. It is natural for the top of the horns to be seated into the platform and washer to accommodate the client s gait 8

9 pattern. Lubricant maintenance will reduce the wear and extend the foot's life span. Lubrication can be repeated if the foot should give any undesired sounding. If sounding persists place the anti-sounding washer provided between the Horns and the 22 mm washer. If the horns have not seated into the foot bolt washer themselves you may need to relieve the inside edges of each horn to clear the 22 mm washer. It is recommended that the registered Niagara Foot be inspected on a biannual schedule and maintained, as necessary, by a recognized & qualified Prosthetist and or their qualified technical representative. Niagara Foot Covers are available in sizes CM, Light Tone (LT) and Medium Brown (MB). 9

10 Assembly Instructions 10

11 Warranty Three Year Limited Warranty REPAIRS/REPLACEMENT If required, the foot will either be repaired or replaced at the Company s option. The repaired or replacement foot will continue to be covered under this Limited Warranty for the remaining duration of the warranty period that commenced on the date of purchase. Unless otherwise specified at the time of replacement, replacement parts, not otherwise covered by this Limited Warranty, will have a 90 day limited warranty, commencing on the Company s shipment date, subject to the same limitations as are set forth in this Limited Warranty. This Limited Warranty does not apply to ordinary wear and tear. No warranty or other liability is provided or accepted by the Company including those otherwise arising for prosthetic services such as fitting, adjusting or maintaining the foot, or for any other acts of omission or commission by the Recognized Prosthetist or other Prosthetist. DAMAGES/LIABILITIES No person, employee, contractor, agent, distributor, dealer or company is authorized to change, modify, or extend the terms of this Limited Warranty in any manner whatsoever. The Company is not liable for indirect, incidental, or consequential damages in connection with the use of the Foot. These damages include, without limitation, loss, damage, or expense attributable to loss of use of the foot, loss or damage to property other than the foot, loss of expected income, loss from business disruption, or other commercial or personal loss due to any cause, even if the Company has been advised of the possibility of such damages, in connection with the foot, or any use of the foot (except for liability for consequential damages to the extent that by law such may not be disclaimed). 11

12 FORCE MAJEURE This Limited Warranty will not apply if a failure(s) of the foot is attributable to (a) neglect, (b) accident (c) misuse, (d) use for applications beyond design specifications, (e) use for purposes other than those expressed or intended by current product literature, (f) abuse, (g) modification or alteration to any component of the foot other than in accordance with the Company s written instructions, (h) exposure of the Foot to fire, corrosive materials such as salt water and PH extremes, or to other conditions beyond the environmental and operating constraints specified by the Company, (i) improper installation of the foot, (j) failure to follow the most current Gait Matching Guidelines that may result in inappropriate component selection (k) failure to satisfy the pre-conditions or other requirements contained herein, (l) failure to strictly comply with the Company s instructions including its Technical Instructions, (m) anatomical, physiological and/or volumetric changes in the patient such as changes in the patient s weight or in the size or shape of the patient s limb, (n) use by anyone other than the original user; (o) failure to follow recommended inspection and maintenance schedules or (p) Exoskeletal finish involving drilling of platform for anti-rotation (q) any other DISCLAIMER With the exception of the foregoing express limited warranty, to the extent permitted by law, the company disclaims all warranties, express and implied, including, without limitation, state law implied warranties of merchantability and fitness for a particular purpose. There are no express or implied warranties, guarantees, agreements or similar obligations of the company, which extend beyond the description on the face of this limited warranty. The invalidity or unenforceability of any provision of this limited warranty shall not affect the validity or enforceability of the remaining provisions hereof. 12