WO2012009735A1

WO2012009735A1 - Articulating prosthesis

Info

Publication number: WO2012009735A1
Application number: PCT/ZA2011/000048
Authority: WO
Inventors: Robert Ian Campbell; Deon Johan De Beer
Original assignee: VAAL UNIVERSITY OF TECHNOLOGY
Current assignee: VAAL UNIVERSITY OF TECHNOLOGY
Priority date: 2010-07-16
Filing date: 2011-07-15
Publication date: 2012-01-19
Anticipated expiration: 2013-01-16

Abstract

This invention relates to prostheses, more particularly to an articulating prosthesis. More particularly, but not exclusively, the invention relates to an articulating prosthesis for a finger or a toe, which may be simply produced to specifically attach the prosthesis to a stub of a given finger or toe, or to the hand or foot itself in the absence of a stub. The invention furthermore also extends to a method of manufacturing such prosthesis. The prosthesis includes: a base adapted to be mountable on a stub of an amputated finger; a tip being pivotably securable to the base and displaceable between an extended position and a retracted position, actuating means for displacing the tip from the extended position to the retracted position, the tip being biased towards the extended position.

Description

ARTICULATING PROSTHESIS

FIELD OF THE INVENTION

This invention relates to prostheses, more particularly to an articulating prosthesis. More particularly, but not exclusively, the invention relates to an articulating prosthesis for a finger or a toe, which may be simply produced to specifically attach the prosthesis to a stub of a given finger or toe, or to the hand or foot itself in the absence of a stub. The invention furthermore also extends to a method of manufacturing such prosthesis.

BACKGROUND OF THE INVENTION

In this specification reference will be made to fingers. It should however be understood that the invention is equally applicable to toes, but for the sake of conciseness the term "finger" will be used throughout this specification.

Articulating fingers are generally complex in design, as they require numerous mechanical parts to facilitate articulation. In addition, conventional prosthesis requires an inherent adjustment, which allows it to fit the stub of a finger. These features generally result in a complex manufacturing process and prosthesis, which in the long term does not provide a snug fit between the stub of the finger articulating prosthesis. Present realisation process are this also expensive and not readily accessible by people in distant areas. Multiple parts negatively impact on reliability and the cost effectiveness of maintenance.

OBJECT OF THE INVENTION

The present invention, therefore, addresses the development of a novel articulating prosthesis, which at least partly alleviates the disadvantages mentioned above.

It is also an object of the invention to provide an articulating prosthesis, which will be a useful alternative to existing prostheses.

SUMMARY OF THE INVENTION

According to the invention, an articulating prosthesis is provided, the prosthesis including: a base adapted to be mountable on a stub of an amputated finger; a tip which is pivotably securable to the base, in order for the tip to be displaceable between an extended position, in which the tip and the base is substantially longitudinally aligned, and a retracted position, in which the tip is angularly displaced relative to the base, with the tip being biased towards the extended position; and actuating means for displacing the tip from the extended position to the retracted position. There is provided for the base to include a receiving formation for receiving the stub of the finger, and an anchoring formation which is securable to the hand or stub.

There is provided for each of the tip, receiving formation and anchoring formation to be in the form of unitary bodies.

The tip may be biased towards the extended position by way of a spring or another suitable resilient element.

The actuating means may be in the form of a flexible elongate element extending between the base and the tip, and more particularly between the anchoring formation and the tip.

There is provided for the actuating element to be configures to displace the tip from the extended position to the retracted position when a tensile force is exerted on the actuating element, and for the tip to be returned to the extended position by the biasing means when the tensile force exerted on the actuating element is removed.

The base and the tip may be made of various polymer materials, including a polyamide, polyester or a polyethylene; while an attachment means which pivotally attaches the stationary body to the movable body may be made of either a metal or an appropriate polymer. The biasing means may include a metal spring, a metal wire, a metal rod and a rod, wire or spring made of an appropriate polymer.

There is provided for at least the tip to comprise a unitary body having zones of different hardness and resilience. According to a further aspect of the invention, a process is provided whereby the patient's hands, both the afflicted hand as well as the other or both afflicted hands - are modelled such that it is possible to construct a data representation of the hands in a location remote from the patient. The data representation or model is used to plan the prosthesis and to customize it for the patient's hands. The final data model is inputted to a digital manufacturing machine and a prosthesis is grown. The prosthesis is sent to the patient for fit and use.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will be described below by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a photograph showing a perspective view of the prosthesis in accordance with the invention;

Figure 2 shows the prosthesis of Figure 1 from an opposite side;

Figure 3 is a photograph of the prosthesis of Figure 1 and 2 mounted on a stub of a partially amputated finger;

Figure 4 shows the mounted prosthesis of Figure 3 from an opposite side; and

Figure 5 is a schematic flow diagram of the method of realizing and manufacturing the prosthesis. DESCRIPTION OF PREFERRED EMBODIMENT

Referring to the figures, in which like numerals indicate like features, an articulating finger prosthesis is generally indicated by reference numeral 10. The prosthesis includes a base 20 and a tip 30, which pivotably secured to the base 20.

The base comprises a receiving formation 21 configured and dimensioned to snugly fit over the stub of an amputated finger, and an anchoring formation 22 to which the actuating means 40 is attached as is described in more detail below. The tip 30 is pivotable secured to the base 20, and more particularly to the receiving formation 21 of the base, and is pivotable between an extended position in which the tip is 30 is substantially longitudinally aligned with the base 20, and a retracted position in which the tip is angularly displaced relative to the base 20. The tip 30 is biased towards the extended position by way of suitable biasing means 50.

In use the anchoring formation 22 is mounted on the remaining stub or joint of the finger, and the end of the joint is inserted into the receiving formation 21. When the remaining stub is bent, a tensile force is exerted on the actuating means 40, thus causing the tip 30 to be displaced against the bias to a retracted or bent position. When the stub is straightened again, the tension in the actuating means 40 is released, and the bias exerted by the biasing means 50 causes the tip to return to the extended position. In this way the position of the tip 30 can be controlled by movement of the stub or remaining joint on the hand.

The prosthesis may include sensors to provide various signals to the patient, including proximity and pressure and temperature. In this embodiment the prosthesis will include ubiquitous intelligence emulating the sensory feedback ordinarily provided by natural fingers. The various parts of the prosthesis may be designed and manufactured to fulfill both the functional and aesthetic requirements. In particular the skin may be designed and grown to more closely emulate the natural finger.

The prosthesis will replace lost functionality to a patient - but may equally be used by fully fit customers desiring enhanced functionality, particularly as a form of exoskeleton with embedded intelligence.

The concept might also have particular value where the patient has relatively little finger loss - in which case the more compact embodiment of the current concept would enable a solution to be generated for the patient.

The more compact embodiment further enables the design and manufacture of a toe prosthesis.

With reference to figure 5, the product realisation and manufacturing process comprises the following steps:

• Step 1. A measuring kit is requested by patient or a person acting on patient's behalf - indicating the scope of loss of fingers. The scope of loss may be used to adjust the size of the measuring kit to be supplied to a particular patient. In another embodiment of the process - measuring kits may be distributed to relevant service points (hospitals, doctors) as part of marketing.

• Step 2. Measuring kit is used to mould the left and right hands of the patient.

If finger loss is restricted to one hand only - this will indicate the area of loss as well as what that area should have looked like prior to the loss (in mirror image). Step 3. Moulds are used to cast representations of the patient's hands. The representations are digitally scanned creating 3D data models of the patient's hands. In another embodiment the cavities inside the moulds may be scanned directly. In another embodiment - the patient's hands might be scanned directly.

Step 4. A generic model of a prosthesis is customized to fit the requirements of the patient.

Step 5. The customized generic model is inputted in a dig ital manufacturing machine and the prosthesis is grown. A special feature is to vary the hardness of the material during the build in order to attain the elements of bone and muscle and skin during the same manufacturing run.

Step 6. The patient fits and uses the prosthesis.

Claims

1 . An articulating prosthesis including: a base adapted to be mountable on a stub of an amputated finger; a tip which is pivotably securable to the base, in order for the tip to be displaceable between an extended position, in which the tip and the base is substantially longitudinally aligned, and a retracted position, in which the tip is angularly displaced relative to the base, with the tip being biased towards the extended position; and actuating means for displacing the tip from the extended position to the retracted position.

2. An articulating prosthesis according to claim 1 , wherein the base includes a receiving formation for receiving the stub of the finger and an anchoring formation which is securable to the hand or stub.

3. An articulating prosthesis according to claim 2, wherein each of the tip, receiving formation and anchoring formation to be in the form of unitary bodies.

4. An articulating prosthesis according to claim 2 or claim 3, wherein the tip is biased towards the extended position by way a biasing means.

5. An articulating prosthesis according to claim 4, wherein the biasing means is a spring or includes a metal spring, a metal wire, a metal rod and a rod, wire or spring made of an appropriate polymer.

6. An articulating prosthesis according to any one of claims 2 to 5, wherein the actuating means is in the form of a flexible elongate element extending between the base and the tip.

7. An articulating prosthesis according to claim 6, wherein the actuating means extends between the anchoring formation and the tip.

8. An articulating prosthesis according to claim 6 or claim 7, wherein the actuating means is configured to displace the tip from the extended position to the retracted position when a tensile force is exerted on the actuating means, and for the tip to be returned to the extended position by the biasing means when the tensile force exerted on the actuating means is removed.

9. An articulating prosthesis according to any one of the preceding claims wherein the base and the tip are made from a group of polymer materials including a polyamide, polyester or a polyethylene.

10. An articulating prosthesis according to any one of the preceding claims wherein the actuating means is made of a metal or an appropriate polymer.

11. An articulating prosthesis according to any one of the preceding claims wherein the tip comprises a unitary body having zones of different hardness and resilience.

12. A process for manufacturing and fitting an articulating prosthesis comprising the steps of:

(A) modelling a patient's afflicted hand, other hand and/or both afflicted hands; (B) constructing a data representation of the hand(s) in a location remote from the patient;

(C) inputting the data representation into a digital manufacturing machine to grow the prosthesis; and

(D) sending the prosthesis to the patient for fitment and use.