USOO8597369B2

(12) United States Patent (10) Patent N0.: US 8,597,369 B2 Hansen et a]. (45) Date of Patent: Dec. 3, 2013

(54) EQUILIBRIUM-POINT PROSTHETIC AND (52) US. Cl. ORTHOTIC ANKLE-FOOT SYSTEMS AND USPC ...... 623/50; 623/ 53; 623/47 DEVICES (58) Field of Classi?cation Search USPC ...... 623/24427, 47456 (75) Inventor 51 Andrew H- Hansen, Round Lake, IL See application ?le for complete search history. (US); Steven A. Gard, Naperville, IL (US); Dudley S. Childress, Wilmette, IL (56) References Cited (US); Brian Ruhe, Chicago, IL (US); Ryan Williams, Albuquerque, NM (US) U-S- PATENT DOCUMENTS (73) Assignees: Northwestern University, Evanston, IL 2 * chlroy """""""""""" " 623/43 , , ampton The Department ofVeteran 4,413,360 A 11/1983 Lamb Affairs, Washington, DC (US); The 4,547,913 A 10/1985 Phillips Rehabilitation Institute of Chicago, 4,555,817 A 12/1985 McKendIick Chicago IL (Us) 6,007,582 A * 12/1999 May ...... 623/55 ’ 6,159,248 A 12/2000 Gramnas ( * ) Notice: Subject to any disclaimer, the term of this gliirclge patent IS extended or adjusted under 35 6,443,993 B1 9/2002 Koniuk U,S,C, 154(b) by 0 days, 6,500,138 B1* 12/2002 Irby et a1...... 602/26 (21) App1.No.: 12/311,818 (Continued) OTHER PUBLICATIONS (22) PCT Filed: Oct. 17, 2007 _ _ _ _ _ Feldman, Once More on the Equ111br1um-p01nt Hypothes1s (lambda (86) PCT NO; PCT/U52007/022208 model) for Motor Control, J. Motor Behav, 18, 1986, pp. 17-54. § 371 (0X1), (Continued) (2), (4) Date: Apr. 13, 2009 _ Primary Examiner * DaV1d Isabella (87) PCT Pub. No.: WO2008/048658 Assistant Examiner * Marcia Hoffman PCT Pub' Date: Apr. 28, 2008 (74) Attorney, Agent, or Firm * Cook Alex Ltd.

(65) Prior Publication Data (57) ABSTRACT The present invention relates to a system for use in rehabili US 2010/0185301 A1 1111' 22’ 2010 tation and/or physical therapy for the treatment of injury or . . disease. The system can enable an amputee to proceed over Related U's' Apphcatlon Data any surface Without overbalancing. In particular the system is (60) Provisional application No. 60/852,174, ?led on Oct. self-adapting to adjust the torque moment depending upon 17, 2006. the motion, the extent of inclination, and the surface topog raphy. (51) Int. Cl. A61F 2/66 (2006.01) 9 Claims, 11 Drawing Sheets US 8,597,369 B2 Page 2

(56) References Cited Hansen, Roll-over Characteristics of Human Walking With Applica tions for Arti?cial Limbs; Dissertation, 2002. U.S. PATENT DOCUMENTS Leroux et al., Postural Adaptations to Walking on Inclined Surfaces: I. Normal Strategies, Gait & Pos., 15, 1, 2002, pp. 67-74. 7,431,737 B2 10/ 2008 Ragnarsdottir et al. Hansen et al., The Human Ankle During Walking: Implications for 2004/0064195 A1* 4/2004 Herr ...... 623/24 2004/0153168 A1 8/2004 Childress et al. Design of Biomimetic Ankle Prostheses, J. Biomech; 37, 10, pp. 2005/0192677 A1 9/200 5 Ragnarsdottir 1467-1474. 2005/0197717 A1* 9/ 2005 Ragnarsdottir et al...... 623/24 Hansen et al., Roll-over Characteristics of Human Walking on 2006/0184280 A1 8/2006 Oddsson Inclined Surfaces; Hum, Mov. Sci.; 23, 6, pp. 807-821. 2006/0224246 A1 * 10/2006 Clausen et al...... 623/24 Prentice et al., Locomotor Adaptations for Changes in Slope of the 2006/0224247 A1 10/2006 Clausen Walking Surface; Gait & Pos.; 20, 3, pp. 255-265. 2006/0249315 A1* 11/2006 Herr et a1...... 180/8.1 Lay, The Effects of Sloped Surfaces on Locomotion: A Kinematic 2007/0043449 A1* 2/2007 Herr et a1. 623/24 2007/0061016 A1* 3/2007 Kuo et a1. 623/24 and Kinetic Analysis, J. Biomech., 39, 9, 2006, pp. 1621-1628. 2009/0319055 A1* 12/2009 Iversen et al...... 623/49 Williams et al., Prosthetic Ankle-Foot Mechanism Capable of Auto matic Adaptation to the Walking Surface; J. Biomech. Eng., 131, 3, OTHER PUBLICATIONS 2009. PCT/US2007/022208 International Search Report. Perry, Gait Analysis: Normal and Pathological Function, 1992, Slack PCT/US2007/022208 Written Opinion of the International Search Inc., 1992. Latash et al., Joint Stiffness: Myth or Reality?; Hum. Mov. Sci, 12, Authority. PCT/US2011/000675 International Search Report. 1993, pp. 653-692. Irby et al., Optimization and Application of a Wrap-Spring Clutch to PCT/US2011/000675 Written Opinion of the International Search a Dynamic Knee-Ankle-Foot Orthosis, IEEE Trans. Rehabll. Eng., 7, Authority. 2, 1999, pp. 130-134. PCT/US2012/000038 International Search Report. Ferris et al., Runners Adjust Leg Stiffness for Their First Step on a New Running Surface; J. Biomech.; 32, 8, pp. 787-794, 1999. * cited by examiner US. Patent Dec. 3, 2013 Sheet 1 0f 11 US 8,597,369 B2

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Ankle Dorsi?exion Anele US 8,597,369 B2 1 2 EQUILIBRIUM-POINT PROSTHETIC AND from a system whereas stiffness can store and release energy ORTHOTIC ANKLE-FOOT SYSTEMS AND to a system throughout a loading and unloading cycle (that is, DEVICES a walking cycle). Recent research has suggested that roll-over shape, the CROSS-REFERENCE TO RELATED effective rocker shape that the ankle-foot system conforms to APPLICATIONS between heel contact and opposite heel contact, is an impor tant characteristic for walking. Hansen ((2002); “Roll-over The present application claims priority to International Characteristics of Human Walking With Applications for Patent Application Number PCT/US07/22208 entitled Arti?cial Limbs.” Ph.D. dissertation, Northwestern Univer “Equilibrium-Point Prosthetic and Orthotic Ankle-Foot Sys sity, Evanston, Ill.) found that the able-bodied ankle-foot tems, Devices, and Methods of Use”, ?led Oct. 17, 2007, system adapts to several walking conditions to maintain a which in turn claimed priority to US. Provisional Patent similar roll-over shape and that its roll-over shape changes Application Ser. No. 60/852,174 entitled “Equilibrium-Point predictably when walking on inclined surfaces. Speci?cally, Prosthetic and Orthotic Ankle-Foot Devices”, ?led Oct. 17, able-bodied ankle-foot systems are capable of automatically 2006, both which are herein incorporated by reference in their adapting to differences in shoe heel height and to different entirety for all purposes. surface inclinations. Current prosthetic ankle-foot mecha nisms cannot automatically adapt to these conditions. Many STATEMENT REGARDING FEDERALLY currently available prosthetic and orthotic ankle-foot mecha SPONSORED RESEARCH OR DEVELOPMENT nisms do not allow ankle motion. Rigid ankle prosthetic and 20 orthotic ankle-foot devices generally attempt to replace the This invention was made with government support under actions of the biologic ankle-foot system through deforma H133E030030 awarded by the National Institute on Disabil tions of their materials and/or by utiliZing rocker shapes on ity and Rehabilitation Research (United States Department of the plantar surfaces. The prosthetic and orthotic ankle-foot Education). The United States government has certain rights devices that do incorporate ankle motion usually allow rota in the invention. 25 tional motion about one equilibrium point that does not change without mechanical adjustments of the prosthesis or TECHNICAL FIELD orthosis. Some of these devices use springs and/ or bumpers to store and release energy and return the device’s ankle joint to The inventions relates to improved prosthetic systems and one equilibrium point. This single and constant equilibrium methods of use. In particular the prosthesic systems comprise 30 point can result in good function on level terrain and when an ankle unit that, in combination with other mechanical using shoes of one particular heel height (heel and forefoot elements of prosthesic systems, enable the gait of an amputee sole differential). However, problems can arise when walking using the device to emulate the gait of able-bodied individual on different terrain or when using shoes of different heel and that automatically adapts the gait to different terrain on height. The heel height problem can be ?xed using a change each and every step. 35 in the alignment of the prosthesis. However, this is not a simple task and one that does not happen automatically. BACKGROUND OF THE INVENTION The prior art demonstrates that there is a current and long felt need for an improved ankle prosthesis or ankle-foot pros Many currently available prosthetic and orthotic ankle-foot thesis that can better emulate the gait of an able-bodied indi mechanisms do not allow ankle motion. Rigid ankle pros 40 vidual and adapt to the terrain on the ?rst step. thetic and orthotic ankle-foot devices generally attempt to replace the actions of the biologic ankle-foot system through BRIEF SUMMARY OF THE INVENTION deformations of their materials and/or by utiliZing rocker shapes on the plantar surfaces. The prosthetic and orthotic The invention provides a prosthetic and orthotic ankle-foot ankle-foot devices that do incorporate ankle motion usually 45 device. The system can be used by a human subject as a allow rotational motion about a single point that does not prosthesis to assist the user’s gait and to prevent or reduce the change without mechanical adjustments of the prosthesis or likelihood of compromising the user’s balance. orthosis. Some of these devices use springs and/ or bumpers to In one embodiment the invention provides a prosthetic store and release energy and return the device’ s ankle joint to system for a user to emulate normal gait, the prosthetic sys one “equilibrium” point. This single and constant “equilib 50 tem comprising an ankle member, the ankle member com rium” point can result in good function on level terrain and prising a reversible engagement means, a ?rst torsion means, when using shoes of one particular heel height (heel and and a joint, and wherein in use, a torsion curve plot of ankle forefoot sole differential). However, problems can arise when moment against ankle dorsi?exion angle of the prosthetic walking on different terrain or when using shoes of different system during a gait cycle comprises at least one transition heel height. The heel height problem can be ?xed using a 55 point, wherein the reversible engagement means is opera change in the alignment of the prosthesis. However, this is not tively connected to the ?rst torsion means, wherein the ?rst a simple task and one that does not happen automatically. torsion means is operatively connected to the joint, and A recent patent issued to Wayne Koniuk (U .S. Pat. No. wherein the joint is operatively connected to the engagement 6,443,993 B1, “Self-Adjusting Prosthetic Ankle Apparatus”, means. In a preferred embodiment the system is used by a user issued Sep. 3, 2002) discloses a device that will adapt to 60 to proceed over a surface without compromising balance various terrains and to shoes of different heel height. How wherein the surface comprises a plurality of grades or eleva ever, Koniuk’ s design does not appear to have energy storage tions. More preferably the torsion curve plot comprises a and release properties, utilizes more sensing devices than the plurality of transition points. In one alternative embodiment proposed design, and does not appear to give plantar?exion at the transition point of the torsion curve plot is at a negative late stance. Koniuk’s design is based on damping control of 65 torque moment. In another alternative embodiment the tran the ankle joint whereas the proposed device is based on the sition point of the torsion curve plot is at a negative ankle control of stiffness about the ankle. Damping removes energy dorsi?exion angle. In another alternative embodiment the US 8,597,369 B2 3 4 transition point of the torsion curve plot is at a positive torque torsion means. Preferably, the second torsion means com moment. In yet another alternative embodiment the transition prises a pair of neutraliZing torsion means. point of the torsion curve plot is at a positive ankle dorsi?ex In one embodiment the invention provides the prosthetic ion angle. In a most preferred embodiment the prosthetic system as disclosed further comprising a foot plate. In another system automatically adapts to different surface conditions. embodiment the prosthetic system further comprises a shin In one embodiment the prosthetic system comprises a com member. In another embodiment the prosthetic system fur position selected from the group consisting of stainless steel, ther comprises a microprocessor. In another embodiment the copper, aluminum, titanium, metal matrix composite, metal prosthetic system further comprises a motor. In another alloy, such as NITINOL, DELRIN (acetal), acrylonitrile embodiment the prosthetic system further comprises an butadiene styrene (ABS), nylon, polypropylene, polybro actuator. In another embodiment the prosthetic system further comprises a potentiometer. mate, polycarbonate, glycolised polyethylene terephthalate The invention also provides a prosthetic ankle-foot device (PETg) copolyester, olytetra?uorethylene (PTFE), ePTFE, for a user to emulate normal gait, the prosthetic ankle-foot polypropylene, a polymer, glass ?ber-resin composites, car device comprising an ankle member, the ankle member com bon ?ber resin composites, and the like. prising a reversible engagement means, a ?rst torsion means, In a preferred embodiment the invention provides a pros and a joint, and wherein in use, a torsion curve plot of ankle thetic system as disclosed wherein the engagement means is moment against ankle dorsi?exion angle of the prosthetic selected from the group consisting of a lock, a piston, a ankle-foot device during a gait cycle comprises at least one ratchet, a clutch, a brake, and the like. In another preferred transition point, wherein the reversible engagement means is embodiment the torsion means is selected from the group 20 operatively connected to the ?rst torsion means, wherein the consisting of a spring, a tunable spring, a clockwork spring, a ?rst torsion means is operatively connected to the joint, and piston, a damper, and the like wherein the joint is operatively connected to the engagement In another embodiment the invention provides a prosthetic means. In a most preferred embodiment the prosthetic ankle system as disclosed further comprising at least one second foot device automatically adapts to different surface condi torsion means. Preferably, the second torsion means com 25 tions. prises a pair of neutraliZing torsion means. The invention also provides a prosthetic prosthetic ankle In one embodiment the invention provides the prosthetic foot device for a user to emulate normal gait, the prosthetic system as disclosed further comprising a foot plate. In another ankle-foot device comprising an ankle member, the ankle embodiment the prosthetic system further comprises a shin member comprising a reversible engagement means, torsion member. In another embodiment the prosthetic system fur 30 means, and a joint, and wherein in use, a torsion curve plot of ther comprises a microprocessor. In another embodiment the ankle moment against ankle dorsi?exion angle of the pros prosthetic system further comprises a motor. In another thetic ankle-foot device during a gait cycle comprises at least embodiment the prosthetic system further comprises an two equilibrium points, wherein the reversible engagement actuator. In another embodiment the prosthetic system further means is operatively connected to the ?rst torsion means, comprises a potentiometer. 35 wherein the ?rst torsion means is operatively connected to the The invention also provides a prosthetic system for a user joint, and wherein the joint is operatively connected to the to emulate normal gait, the prosthetic system comprising an engagement means. ankle member, the ankle member comprising a reversible The invention also provides a prosthetic prosthetic ankle engagement means, torsion means, and a joint, and wherein in foot device for a user to emulate normal gait, the prosthetic use, a torsion curve plot of ankle moment against ankle dor 40 ankle-foot device comprising an ankle member, the ankle si?exion angle of the prosthetic system during a gait cycle member comprising a reversible engagement means, torsion comprises at least two equilibrium points, wherein the revers means, and a joint, and wherein in use, a torsion curve plot of ible engagement means is operatively connected to the ?rst ankle moment against ankle dorsi?exion angle of the pros torsion means, wherein the ?rst torsion means is operatively thetic ankle-foot device during a gait cycle comprises at least connected to the joint, and wherein the joint is operatively 45 two equilibrium points and wherein at least one of the two connected to the engagement means. In a preferred embodi equilibrium points set is based upon the step conditions. In a ment the system is used by a user to proceed over a surface preferred embodiment, the step condition is selected from the without overbalancing wherein the surface comprises a plu group consisting of speed or velocity, slope of terrain, and rality of grades or elevations. eveness of surface. In the alternative, at least one of the More preferably the torsion curve plot comprises a plural 50 equilibrium points set during the gait cycle. ity of transition points. In one alternative embodiment the The invention further provides a method for providing transition point of the torsion curve plot is at a negative torque normal gait in an amputee, the amputee having lost a lower moment. In another alternative embodiment the transition limb extremity, the method comprising (i) providing the pros point of the torsion curve plot is at a negative ankle dorsi?ex thetic system as disclosed herein; (ii) attaching the prosthetic ion angle. In another alternative embodiment the transition 55 system to the lower limb of the amputee; (iii) allowing the point of the torsion curve plot is at a positive torque moment. amputee to ambulate for at least one gait cycle, the gait cycle In yet another alternative embodiment the transition point of comprising at least two phases of dorsi?exion over time, the torsion curve plot is at a positive ankle dorsi?exion angle. whereby a load applied during a ?rst phase of dorsi?exion In a preferred embodiment the invention provides a pros results in the engagement means engaging and damping thetic system as disclosed wherein the engagement means is 60 movement of the engagement means, wherein during the ?rst selected from the group consisting of a lock, a piston, a phase when the ankle dorsi?exion angle is at an ankle angle ratchet, a clutch, a brake, or the like. In another preferred minimum the engagement means engages and dampens fully, embodiment the torsion means is selected from the group and wherein during a second phase of dorsi?exion when the consisting of a spring, a tunable spring, a clockwork spring, a ankle dorsi?exion angle is at another ankle angle minimum piston, or the like. 65 the engagement means disengages and releases fully, the In another embodiment the invention provides a prosthetic method resulting in providing normal gait to the amputee. In system as disclosed further comprising at least one second one preferred embodiment the gait cycle comprises at least US 8,597,369 B2 5 6 three phases of ankle ?exion. In another preferred embodi upper member, wherein the ankle joint further comprises a ment, the engagement and dampening of the engagement pair of arms, each arm having a ?rst end and a second end, a means coincides with a ?rst transition point of the torsion pair of ?rst bumpers, a pair of bearings, a pair of second curve plot. In yet another preferred embodiment, the disen bumpers, the second bumpers positioned longitudinally along gagement and release of the engagement means coincides the length of the foot member, a base, a ?rst shaft, a second with a second transition point of the torsion curve plot. shaft, a third shaft, a fourth shaft a pair of braces, a cam, the In an alternative embodiment, the invention provides the cam having an off-center ?rst aperture, and optionally, a cam method of using the prosthetic system further comprising a allowing rotation in one direction but not the other, at least step of determining an equilibrium point of a torsion curve one second aperture, and a recess, the recess shaped and plot wherein an equilibrium point of the torsion curve plot is adapted to receive a link, the ?rst aperture shaped and adapted at a negative dorsi?exion angle. In an alternative embodiment for receiving a ?rst shaft therethrough and wherein the ?rst an equilibrium point of the torsion-curve plot is at a positive shaft can revolve therein, a housing, the housing having at dorsi?exion angle. least two threaded apertures shaped and adapted to receive a In a still further embodiment the invention provides a bolt, the link connected to the housing using a fourth shaft method for providing normal gait in an amputee, the amputee positioned through a ?rst link aperture in the link and a least having lost a lower limb extremity, the method comprising (i) one aperture located in a ?ange abutting from the housing and providing the prosthetic ankle-foot device as disclosed having at least one second link aperture at the end of the link herein; (ii) attaching the prosthetic ankle-foot device to the opposing the housing, at least two bolts, at least two compres lower limb of the amputee; (iii) allowing the amputee to sion springs, an adaptor, the adaptor having at least two bolt ambulate for at least one gait cycle, the gait cycle comprising 20 apertures shaped and adapted for receiving a bolt there at least two phases of dorsi?exion over time, whereby a load through, at least two set screws, wherein the arm has a ?rst applied during a ?rst phase of dorsi?exion results in the apertures located at the ?rst end and a second aperture located engagement means engaging and damping movement of the at the second end, the apertures sized and spaced to receive a engagement means, wherein during the ?rst phase when the second shaft therethrough and wherein the second shaft can ankle dorsi?exion angle is at an ankle angle minimum dorsi 25 revolve therein, wherein the base has at least one aperture, the ?exion the engagement means engages and dampens fully, aperture sized and spaced to receive the second shaft there and wherein during a second phase of dorsi?exion when the through, wherein the bearings are in lateral opposition ?xedly ankle dorsi?exion angle is at another ankle angle minimum attached to the foot member, the ?rst end of the arms posi dorsi?exion the engagement means disengages and releases tioned between the two bearings and in contact with the ?rst fully, the method resulting in providing normal gait to the 30 bumpers, the ?rst bumpers secured to the foot member and amputee. In one preferred embodiment the gait cycle com supporting the arms, the base centered between the two bear prises at least three phases of ankle ?exion. In another pre ings and in contact with the second bumpers, wherein the ferred embodiment, the engagement and dampening of the braces are positioned and secured between the second end of engagement means coincides with a ?rst transition point of the arms, wherein the cam is centered between the second end the torsion curve plot. In yet another preferred embodiment, 35 of each arm and having a surface in intermittent contact with the disengagement and release of the engagement means a surface of the base, the surface contact dependent upon the coincides with a second transition point of the torsion curve rotated position of the cam, wherein the link aperture is posi plot. tioned in-line with the second aperture of the cam and a third In an alternative embodiment, the invention provides the shaft positioned therethough and wherein the third shaft can method of using the prosthetic system further comprising a 40 revolve therein, wherein the adaptor is positioned proximal to step of determining an equilibrium point of a torsion curve the housing, wherein each bolt is positioned through an aper plot wherein an equilibrium point of the torsion curve plot is ture in the adaptor and is threaded into a threaded aperture in at a negative dorsi?exion angle. In an alternative embodiment the housing, wherein each compression spring is placed lon an equilibrium point of the torsion curve plot is at a positive gitudinally encircling the bolt thread between the bolt head dorsi?exion angle. 45 and the adaptor, and the bolt is reversibly threaded through the In one preferred embodiment, the torsion means are housing bolt aperture and into a threaded recess in the second selected from the group consisting of an elastic element, a end of the arm. In one embodiment second bumper is sub spring, a piston, and the like. stantially stiff. In an alternative embodiment the ?rst bumper In a more preferred embodiment, the equilibrium point [3 of is substantially soft. In an alternative embodiment the pros the torsion curve plot is calculated using the equation 50 thetic foot further comprises a pair of spacers, the spacer shaped and adapted for placement between a bearing and an arm. where Tts?orque due to triceps surae spring(s); GIankle dor In a preferred embodiment the prosthetic ankle-foot device si?exion angle; [3:ankle angle at the trigger time; and kts is the has a plurality of equilibrium points, when used as disclosed impedance factor. In an alternative more preferred embodi 55 herein. ment the equilibrium point Q of the torsion curve plot is In another preferred embodiment the prosthetic ankle-foot calculated using the equation has a plurality of transition points, when used as disclosed herein. In one embodiment the relative position of the transi tion point can be controlled, such as for example, by a micro where Tns?orque due to neutralizing spring(s); GIankle dor 60 processor, a motor, an actuator, by the user, a force generator, si?exion angle;