The present invention relates generally to the field of medical products. More specifically, the present invention relates to a prosthetic foot.
In recent years, the need to restore the form and function for people with limb loss is ever increasing. According to the statistics and calculation processes of the World Health Organization (WHO), approximately 0.5% of the population (or 400,000 peoples) have access to prosthetic care and to receive physical therapy assistances. In Vietnam, this need is pressing because of the natural disasters, traffic accidents, and land mines accidents. In addition, limb loss can be the result of trauma, malignancy, disease such as peripheral vascular disease, or congenital anomaly.
For the above reasons, many prosthetic products are conceptualized, developed, and commercialized by different health and physical therapy companies. However, the majority of the prosthetic products in the market today is commonly comprised of different components connected together with an elastic mechanism, e.g., springs. When a patient walks, the prosthetic foot is compressed and released providing a propulsion when the patient lifts and makes a next step. As a result, the walking motion is awkward and unnatural. The conventional prosthetic feet fail to satisfy the need to recover the function and form for the patients with limb loss. More particularly, the conventional prosthetic feet fail to improve the walking posture, causing side effects such as spending unnecessary energy, increasing pressures on the subtalar joint, knee joint, and the hip joint.
The conventional prosthetic limbs are made from different parts assembled together. Therefore, they fail to synchronize the musculoskeletal movements of the real feet. Even the technique disclosed by Scott Summit in U.S. Pat. No. 8,366,789 attempts to improve the performance of a prosthetic limb, only the generic surface is adjusted to assimilate to the intact limb. The end of the amputated limb is also measured to design the socket. However, the prior art Summit's prosthetic limb is still constituted of discrete gears such as circular feature 653, AC clamp 971, etc. operating together to make the walking possible. The prior art Summit's prosthetic limb is rigid, unnatural, and mechanical. In addition, Summit's prosthetic limb is expensive and assembly time is high. Prior art prosthetic foot either does not pay attention to the malleolus bone (ankle bone) or designed them very stiff. Prior or conventional designs do not pay attention to the subtalar joint or designed the subtalar joint without flexibility.
Therefore what is needed is a prosthetic limb based on the flexible mechanism and the elasticity of the composite material which absorbs vibrations avoiding the effects on the subtalar joint. Furthermore, there is a need for a prosthetic foot that stores kinetic energy in order to provide a propulsion for the next step. There are needs for structure that does not have any joints, no gaps between joints, no friction, high-precision, manufactured from a single-piece mold or from 3D printing technology that decreases costs and assembly time.
Accordingly, an objective of the present invention is to provide a prosthetic foot that includes a socket assembly configured to connect to a natural limb of a patient, a sideway cylindrical ankle joint having a maze-like internal structure laterally affixed to the socket assembly; a foot assembly, laterally affixed to the sideway cylindrical ankle joint, having a dorsal portion, a phalange portion, a sole portion, and a heel portion; the phalange portion having a first end connected to the dorsal portion and a second end connected to the sole portion, the sole portion having an arch shape and connected to the heel portion; and the heel portion having a spring assembly connected to said cylindrical ankle joint.
Another objective of the present invention is to provide a method of fabricating a prosthetic foot including the steps of: (a) providing a mold having a socket section, a sideway cylindrical ankle joint section having a maze-like internal structure laterally affixed to the socket section; a foot section, laterally affixed to the sideway cylindrical ankle joint section, having a dorsal portion, a phalange portion, a sole portion, and a heel portion; the phalange portion having a first end connected to the dorsal portion and a second end connected to the sole portion, the sole portion having an arch shape and connected to the heel portion; and the heel portion having a spring assembly connected to the cylindrical ankle joint section; (b) filling the mold with compliant composite such as Glass Fiber Reinforced Plastic (GFRP); and (c) removing the mold to obtain the prosthetic foot in accordance to the present invention.
Another objective of the present invention is to design and to use 3D printing technology to print a single piece prosthetic foot described above.
Another objective of the present invention is to achieve the above-described prosthetic foot that is capable of absorbing vibration so as to avoid injury to the tibula bone and store energy due to exogenous force.
Another objective of the present invention is to achieve the ankle joint comprises a series of flexible springs organized into the structure similar to the malleolus bones of the ankle so as to provide flexibility and absorb shock or vibrations.
Another objective of the present invention is to achieve a prosthetic foot in which the dorsal is designed according to an asymptotic curve principle having flexible parallel cuts or patterns similar to the wings of a dragon flies;
Moreover, another objective of the present invention is to achieve the above described prosthetic foot made of a compliant composite material such as Glass Fiber Reinforced Plastic (GFRP) used having the ability to store energy and then release it to provide a propulsion force for the next step taken by a user;
In another objective, the horizontal and vertical slits enable the prosthetic foot to achieve movements analogous to the real foot in term of folding the sole, the metatarsal when an external force exerts thereupon due to the uneven ground.
The object of this invention is to provide a prosthetic foot to help limb-loss people to achieve full recovery and assimilate back into the community;
Another objective of the invention is to provide a low cost prosthetic foot manufactured from a single mold or from a 3D printer.
These and other advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments, which are illustrated in the various drawing Figures.
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present invention.
Referring now to
Continuing with
In some implementations of the present invention, dorsal portion 131 has an arch asymptotic to the shape of the metatarsal bone. Dorsal portion 131 further comprises an upper membrane 131_3 and a lower membrane 1312, each having a plurality of vein patterns forming a plurality of cells similar to a dragonfly's wing pattern.
Socket assembly 110 is consisted of a connector 111 connected to a base portion 112. In one exemplary embodiment, connector 111 has a shape of an inverted truncated pyramid and base portion 112 has a shape of a truncated cone shape. Other shapes and structures of connector 111 and base portion 112 are within the scope and therefore made obvious by the present invention.
Continuing with
As shown in
Back heel portion 135 further comprises first spring 1351 parallel to second spring 1352, each having a zigzag shape.
Now referring to
Next referring to
Next referring to
Referring again to
The support phase is the time when prosthetic foot 100-400 touches the ground and when sole portion 133 lifts out of the ground. The support phase is further divided into the time when heel portion 134 is off ground, sole portion 133 is flat to the ground, arch 133_2 touches the ground, heel portion 134 off the ground and pre-swing period (when phalange portion 132 off the ground).
In the swing phase, this phase starts when sole portion 133 lifts off from the ground to the time it touches the ground again. This phase is further divided into pre-swing, mid-swing, and terminal swing. Moreover, in sideway cylindrical ankle joint 120, 320, or 420 (the tibia and fibula bone right above the ankle) provides an angular momentum when dorsal portion 131 or 231 (the metatarsal) has a short fold in the beginning of the support phase when sole portion 133 or 233 first touches the ground. The transition to the folding momentum of the sole portion 133 or 233 to control the rotation of the leg upon prosthetic foot 100-400. Afterward the momentum continues to fold sole portion 133 or 233 when the design and the compliant composite material in foot portion 130-430 contracts at the center of gravity to propel prosthetic foot 100-400 forward. At the beginning of this phase, prosthetic foot 100-400 swings, the folding of sole portion 133 or 233 continues due to the implementations described above in accordance with the present invention. Then sole portion 133 or 233 contracts at the center of the gravity. In the mid-swing, prosthetic foot 100-400 swings there is a little force felt at the calf bone.
The support phase is the time when prosthetic foot 100-400 is on the ground. It comprises about 60% of the walking cycle. For part of the support phase, both feet will be on the ground for a period of time. The support phase is further divided into five sub-stages that prosthetic foot 100-400 undergoes. They are as follows. Heel strike, early flatfoot, late flatfoot, Heel rise, and toe off.
The heel strike phase starts the moment when heel portion 134 first touches the ground, and lasts until prosthetic foot 100-400 is on the ground (early flatfoot stage).
The beginning of the “early flatfoot” stage is defined as the moment that the whole prosthetic foot 100-400 is on the ground. The end of the “early flatfoot” stage occurs when the body's center of gravity passes over top of prosthetic foot 100-400. The body's center of gravity is located approximately in the pelvic area in front of the lower spine, when a patient (not shown) stands and walks. The main purpose of the “early flatfoot” stage is to allow prosthetic foot 100-400 to serve as a shock absorber, helping to cushion the force of the body weight landing on prosthetic foot 100-400.
In the late flatfoot stage: once the body's center of gravity has passed in front of the neutral position, the late flatfoot stage occurs. The “late flatfoot” stage of gait ends when heel portion 134 lifts off the ground. During the “late flatfoot” phase of gait, prosthetic foot 100-400 needs to go from being a flexible shock absorber to being a rigid lever that can serve to propel the body forward.
In the heel raise phase: as the name suggests, heel portion 134 rise phase begins when heel portion 134 begins to leave the ground. During this phase, the foot functions as a rigid lever to move the body forward. During this phase of walking, the forces that go through prosthetic foot 100-400 are quite significant: often 2-3x a person's body weight. This is because prosthetic foot 100-400 creates a lever arm (centered on the ankle), which serves to magnify body weight forces. Given these high forces and considering that the average human takes 3000-5000 steps per day (an active person commonly takes 10,000 steps/day). The implementations of prosthetic foot 100-400 enable the user to avoid chronic repetitive stress-related problems, such as metatarsalgia, bunions, posterior tibial tendon dysfunction, peroneal tendonitis, and sesamoiditis.
Finally, the toe off stage of gait begins as phalange portion 132 leave the ground. This represents the start of the swing phase.
Now referring to
At step 501, a prosthetic foot comprised of a socket section, a sideway cylindrical ankle joint having a maze-like structure, and a foot section is designed.
By way of specific examples, as shown in
At step 502, after the design is completed, it is printed out using a 3D printer. In many implementations of step 502, 3D printing software can be used to print the entire prosthetic foot 100-400 in a single integral piece using Glass Fiber Reinforced Plastic (GFRP).
Alternatively, at step 503, a single integral mold is fabricated using the design of step 501.
Next, at step 504, the mold is filled with a compliant composite material. Step 502 is implemented using a such as Glass Fiber Reinforced Plastic (GFRP).
Finally, at step 505, the mold is removed. In implementation, the mold is removed to achieve prosthetic foot 100-400 as described in
The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.