Orthopedic brace for knee joints

The orthopedic brace serves the purpose of splinting and balancing the lateral instability of knee joints and is characterised by a tie-plate intended to be applied to the side of the knee joint having the preponderant instability, which is acted upon by elastic belt straps which lead to fastening points situated above and below as well as laterally offset with respect to the tie-plate. The lines of action of two mutually adjacent belt straps in each cases intersecting each other in the region of the tie-plate.

The invention relates to an orthopedic brace for splinting and for 
balancing the lateral instability of knee joints. 
Orthopedic braces of this nature comprise an upper and a lower splint 
elements of rigid material flanking the upper and lower parts of human 
legs to a greater or lesser extent, the two splint elements being 
interconnected by means of a hinge-like joint. It is disadvantageous that 
an orthopedic brace of this nature does not allow of the natural combined 
rolling and sliding action of the physiological sequence of motion during 
the bending and straightening of the human knee, which leads to an 
unnatural and deleterious strain on the joint-forming bone surfaces of the 
thigh and lower thigh bones, and causes the onset of muscular atrophy in 
the upper and lower parts of the leg. This is a consequence of the lateral 
rigidity of the orthopedic brace. Furthermore, the knee movement imposed 
on the knee by this already known orthopedic brace results in the 
disadvantage that the patient finds it unpleasant to wear the orthopedic 
brace, in particular also because of the lateral rigidity of the 
orthopedic brace. 
The object of the invention consists in devising an orthopedic brace of the 
kind defined in the foregoing, which allows of the lateral sequence of 
motion of the knee and is pleasant to wear. 
The solution to this problem is based on the orthopedic brace specified and 
is characterised by a tie-plate intended to be applied on the knee joint 
side having the preponderant instability and acted upon by elastic belt 
straps which lead to fastening points situated offset above and below as 
well as laterally with respect to the tie-plate, the lines of action of 
two mutually adjacent belt straps in each case intersecting each other in 
the region of the tie-plate. 
Thanks to this solution, the natural sequence of motion of the 
joint-forming bone surfaces of the thigh and lower thigh bones is assured 
under satisfactory balancing of the lateral instability of the knee joint, 
since no movement of any kind is imposed on the knee joint by the 
orthopedic brace. The muscular atrophy referred to is averted thereby. 
Furthermore, the orthopedic brace according to the invention is pleasant to 
wear, since the tie-plate and the straps acting on the same may yield to 
the individual movements of all the knee elements playing a part in the 
movement of the knee in its area, without causing unpleasant feelings of 
pressure or the like. The patient's willingness to wear the orthopedic 
brace readily is also promoted thereby, which for its part is beneficial 
to the curative intent.

According to the figures, the orthopedic brace illustrated, which is to be 
worn by the patient in the region of the knee, for example after plastic 
knee ligament replacement, comprises a tie-plate 1, an upper shackle 2, a 
lower shackle 3 and several elastic belt straps 4,5,6 and 7. The belt 
straps act on the tie-plate 1 on the one hand, and are secured on the 
other hand to fastening points of the two shackles 2,3, e.g. by means of 
rivets 8, these points being situated on the shackles offset sideways with 
respect to the tie-plate, as clearly apparent from FIG. 1. The attachment 
of the belt straps on the tie-plate may be released and may for example be 
performed in such manner that splice straps 9,10 are provided with loops 
11,12, the belt straps being passed through the loops as illustrated. Two 
of the splice straps 9 and 10 in each case are fastened to the tie-plate 
1, e.g. by means of a rivet 13. Furthermore, the belt straps extend from 
the shackles 2,3 in the direction towards the tie-plate, in such manner 
that the lines of action of two mutually adjacent belt straps in each case 
intersect each other in the region of the tie-plate, as clearly apparent 
from FIG. 1. In this connection, let it be stated too that the belt straps 
or rather splice straps are so secured by the rivets 8 and 13, 
respectively, that a pivotal displacement of these parts is possible 
around the rivet axis, so that the belt straps may be movable in a 
particular degree upon donning and wearing the orthopedic brace. 
The belt straps 4,5,6 and 7 which are elastic longitudinally as well as 
transversely, are so formed moreover that they are provided at one side 
with a so-called "Velcro" closure. The structure and function of a closure 
design of this kind are generally known, so that a precise description in 
this connection is superfluous. 
The two shackles 2 and 3 each consist of a comparatively rigid material 
section 2a and 3a, resp., e. g. of plastics material, and of a flexible 
lashing strap 2b and 3b, resp., the one extremity of the strap being 
secured to the material section, for example by rivetting, whereas its 
other extremity is releasably fastened to the material section. The latter 
action may again be performed as described and depicted in connection with 
the belt straps 4 to 7. It is merely on the score of clearness that this 
is not illustrated in the drawings. When the orthopedic brace is fitted on 
the leg of a patient, the material sections 2a,3a of the shackles 2 and 3 
resp., which are rigid in axial direction but flexible in radial 
direction, in each case partially enflank the thigh and lower leg of the 
patient, whereas the lashing straps 2b,3b which are equally provided with 
a "Velcro" closure, residually overbridge the leg parts. 
The tie-plate 1 comprises a rigid material element 1a, e.g. of plastics 
material, and a resilient padding covering 1b, e.g. of an expanded 
material, which is preferably secured by bonding on the side of the rigid 
material element facing towards the patient's knee. 
The rigid material elements 2a,3a of the shackles 2 and 3 are also provided 
at the inner side with a resilient padding covering 14, e.g. of expanded 
material, to obtain a pleasant contact of the shackles on the patient's 
leg. 
So that the shackles 2,3 may be kept spaced apart with respect to the 
tie-plate 1, at least one flexurally elastic bar 15 consisting of plastics 
material for preference is provided, which is installed on the shackles 
and on the tie-plate by means of securing elements 16 which are rivetted 
on. The elements 16, e.g. constructed in the form of a solid journal 
bearing, comprise a bore 17 through which the bar 15 is pushed. So that 
the bar may be secured axially in the elements 16, the latter have tapped 
holes, wherein engage screws 18 which may be acted upon from the outside, 
which are jammed against the bar. Thanks to this method of immobilising 
the bar in the elements, the spacing between the shackles and the 
tie-plate may be set to correspond to the conditions on the patient's 
knee. The cross-sectional shape of the bar 15 may be circular, but oval 
too. The latter will be utilised if a greater flexural rigidity of the bar 
is desirable because of increased instability, the long axis of an oval 
bar extending substantially parallel to the axis of the patient's knee 
joint after the orthopedic brace has been fitted.