Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/50—Prostheses not implantable in the body
  • A61F2/60—Artificial legs or feet or parts thereof
  • A61F2/64—Knee joints
  • A61F2/642—Polycentric joints, without longitudinal rotation
  • A61F2/644—Polycentric joints, without longitudinal rotation of the single-bar or multi-bar linkage type

Definitions

• the present invention relates to an artificial knee- joint according to the preamble of Claim 1.
• the gait of a thigh amputee is considerably different to that of the gait of a normal healthy person, due to the absence of important muscle groups. Because of the loss of the knee muscles, the amputee can no longer bend and then again actively stretch the knee-joint under load.
• the prevention of leg collapse in the supporting phase i.e. that period in which the foot is in contact with the ground or like surface, has only been achieved with a greater or lesser degree of security.
• differing degrees of supporting-phase stability have been achiev ⁇ ed.
• the prothestetic leg is fitted to the amputee with the knee straight, and the knee then remains straight during a major part of the supporting phase.
• the knee-joint mechanism is very stable, it is not possible to bend the knee until the supporting phase is ter ⁇ minated. This impossibility of bending the knee at the beginning and the end of the supporting phase means that the amputee must consume more energy when walking.
• the absence of calf muscles also means that the gait of the person wearing the prosthesis is more energy de ⁇ manding than the gait of a normal person.
• the present artificial knee-joint is constructed to imitate the working mode of the human knee-joint, so that the amputee is able to walk with a natural gait.
• the knee-joint can be said to be a further development of the existing quadruple-joint polycentric type of joint.
• polycentric joint is meant here that the rotational centre has different positions at different knee-joint angles, i.e. there are several pivot cen ⁇ tres.
• the human knee-joint is also polycentric.
• polycentrical quadruple-jointed knee is meant a knee in which the thigh part and the lower-leg part are mutu ⁇ ally joined by two linkage mechanisms, each being pivo ⁇ tally connected at its respective ends to the thigh part and the lower-leg part. This results in four pivot points.
• Quadruple joint mechanisms are now the most common joints available. However, in order to achieve high supporting-'phase stability, it is necessary to supplement these mechanisms with some form of mechani ⁇ cal/hydraulic lock or brake device. The earlier known technical solutions generally cause the knee-joint to become highly complex and undesirably heavy.
• a knee-joint which comprises linkage mechanisms in which locking is effected by means of a catch with the knee straight, this catch being released by means of a linkage mechanism which transmits move ⁇ ment of the toe-part to the knee-joint.
• a serious drawback is that the knee-joint is apparently too heavy for practical use and results in an unnatural termination of a walk ⁇ ing step.
• the object of the present invention is to provide an improved polycentric knee-joint which has high supporting-phase stability, which is light in weight and with which locking of the knee-joint is effected automatically in a simple fashion as a result of the construction and design of the knee-joint, and also to eliminate the drawbacks encountered with earlier known techniques.
• the artificial knee-joint mentioned in the introduction is constructed in the manner de ⁇ fined in the characterizing clause of Claim 1.
• the inventive knee-joint is a polycentric joint and in ⁇ cludes a linkage mechanism consisting of a plurality of linkage arms of varying lengths which are mutually arranged to achieve high supporting-phase stability and a simple, automatic locking function.
• This locking function is effective solely in an extended position and solely when load is exerted on the heel.
• the locking mechanism is released automatically. This means that the locking mechanism will not prevent natural termination or completion of a walking step.
• Figure 1 illustrates schematically a preferred embodi ⁇ ment of the invention
• Figure 2 illustrates different angular positions of the embodiment shown in Figure 1 in a normal course of movement
• Figure 3 illustrates another working method of the embodiment illustrated in Figure 1, which allows different angular positions with bending up to 180 degrees; and
• Figure 4 illustrates the embodiment in a skiing, ice- skating or dancing position.
• the knee-joint illustrated in Figures 1-4 comprises linkage mechanisms which include two base link-arms and seven pivot points.
• a thigh part C has two pivoted attachment points 1, 2 mounted on the underside of a cup-shaped structure 3, which is intended to be secured to the thigh in a conventional fashion.
• Two base arms A, B extend respectively from the aforesaid attachment ponts 1, 2 to attachment elements 4, 5 on the lower leg.
• a lower-leg part D is constructed around an elongated part 6, which is constructed to carry an artificial foot 7 at its lower end and to carry a first attach ⁇ ment element 4 at its upper end.
• a second attachment element 5 is mounted on the rear side of the elongated part 6, preferably within the range of from one to three-quarters of the length of the lower leg.
• These attachment elements 4, 5 are intended to receive the two base arms A, B extending from the cup-shaped part 3.
• the attachment elements 4, 5 can also be considered as a form of moveable linkage mechanisms or rocker means.
• the first attachment element 4 mounted on the upper end of the lower-leg part D can be described as a linkage mechanism having a slightly curved V-shape with three pivot points 8, 9, 10, of which the pivot point 9 is mounted or located between the other pivot points and is connected to the elongated part 6 of the lower leg.
• the first attachment element 4 functions as an attachment means for the base arms A, B and also as a balance-holding device whose movement is contingent on the movement of the centre of gravity of the person's body.
• the pivot point 9 is the point around which the first attachment element moves.
• the base arms A, B, which extend from the thigh part, are connected to the two pivot points 8, 10.
• the lock-stop device 13 is arranged in a manner to normally provide a distinct limitation of the forward movement of the attachment element 5 and is therefore manufactured from a rigid material, preferably metal.
• the stop 13 may be made of a metallic material which is covered with an elastic or resilient material, or the stop and/or parts coacting therewith may alternatively be made of a material which provides a corresponding function.
• the knee-joint functions in the following manner.
• the first attachment element 4 will move clockwise around the pivot point 9 and force the second attachment element 5 to move towards the lock-stop device 13.
• the second attachment element 5 As long as weight is exerted on the heel, it is impossible for the second attachment element 5 to open and move clockwise, even if considerable forces attempt to bend the joint.
• the locking effect is amplified instead.
• the gait of the person wearing the prosth ⁇ esis will be highly similar to the gait of a normal person in setting the heel onto the ground, with subse ⁇ quent locking of the knee-joint.
• the attachment element 5 may also have a given degree of resiliency against the lock-stop device 13, thereby enabling the joint to bend slightly in its locked state, which also contributes to a more natural gait.
• the first attachment element 4 When exerting load on the forward part of the foot, the first attachment element 4 will rock over in an anti ⁇ clockwise direction.
• the second attachment element 5 When the knee-joint is subjected to bending forces, the second attachment element 5 is able to open freely and the leg is able to swing quite freely. This takes place when it is natural to terminate or complete a walking step.
• Figure 3 illustrates a movement pattern which includes a bend of 180 degrees.
• the lock-stop device is removed and the second attachment element 5 moves in an opposite direction compared with the normal movement.
• the drawback with this movement pattern is that when the knee-joint is in a half-bent position the lower leg will be located more forwardly than in a corresponding position with a normal movement pattern. In turn, this results in a smaller lever-arm for the thigh when walking upstairs and when cycling. This state of the knee-joint is intended, however, for use when wishing to fully bend the leg.

Landscapes

• Health & Medical Sciences (AREA)
• Transplantation (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Cardiology (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Prostheses (AREA)
• Materials For Medical Uses (AREA)
• Steroid Compounds (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20379059

Family Applications (1)

Country Status (12)

Cited By (3)

Families Citing this family (30)

Citations (2)

Family Cites Families (7)

• 1990
  • 1990-04-02 SE SE9001183A patent/SE469739B/sv not_active IP Right Cessation
• 1991
  • 1991-03-28 AU AU76676/91A patent/AU7667691A/en not_active Abandoned
  • 1991-03-28 AT AT91907567T patent/ATE123646T1/de not_active IP Right Cessation
  • 1991-03-28 EP EP91907567A patent/EP0523146B1/en not_active Expired - Lifetime
  • 1991-03-28 ES ES91907567T patent/ES2075441T3/es not_active Expired - Lifetime
  • 1991-03-28 JP JP03507075A patent/JP3128237B2/ja not_active Expired - Fee Related
  • 1991-03-28 DK DK91907567.1T patent/DK0523146T3/da active
  • 1991-03-28 CA CA002079587A patent/CA2079587C/en not_active Expired - Fee Related
  • 1991-03-28 US US07/941,041 patent/US5314498A/en not_active Expired - Lifetime
  • 1991-03-28 DE DE69110457T patent/DE69110457T2/de not_active Expired - Lifetime
  • 1991-03-28 WO PCT/SE1991/000240 patent/WO1991015170A1/en active IP Right Grant
• 1995
  • 1995-09-06 GR GR950402447T patent/GR3017318T3/el unknown

Patent Citations (2)

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