Knee brace having an inflatable pad circumscribing the patella

A knee brace is provided that is mountable over the knee joint of a user. The brace has a compliant sleeve and a compliant cover overlying an anterior portion of the sleeve. The sleeve and cover preferably have corresponding anterior openings aligned to receive the patella when the brace is mounted over the knee joint. The sleeve and cover are joined around the perimeter of the cover to form a pocket therebetween enclosing an inflatable pad having a medial chamber and a lateral chamber in fluid isolation from each other. The chambers are provided with associated pumps and valves, rendering them selectively inflatable or deflatable. In operation, the brace is positioned over the knee joint such that the pad circumscribes a portion of the patella and one or both of the chambers are inflated as desired to stabilize the patella.

TECHNICAL FIELD 
The present invention relates generally to orthopedic braces, and 
particularly to an orthopedic brace containing a pad that applies a force 
against the knee of a user for stabilizing the knee. More particularly, 
though not exclusively, the present invention relates to such an 
orthopedic brace, wherein the pad is inflatable to selectively adjust the 
degree and direction of force against the patella of a user thereby 
maintaining the patella in a biomechanically correct position. 
BACKGROUND OF THE INVENTION 
It is recognized that many soft tissue conditions or injuries relating to 
the knee joint result from patellar dislocation. Consequently, a number of 
orthopedic knee braces have the primary function of isolating and 
stabilizing the position of the patella. For example, U.S. Pat. No. 
4,370,978 discloses a knee brace having an elastic sleeve with a patellar 
opening. A pair of resilient pads are sewn to the inside of the sleeve to 
engage the medial and lateral sides of the patella and apply opposing 
balanced forces thereto when the brace is positioned on the leg of a user. 
U.S. Pat. No. 4,201,203 discloses a knee brace having an elastic sleeve 
having a selectively fixed patellar opening to receive and tightly embrace 
various sized patellas. A single resilient pad configured to engage the 
sides of the patella is displacably affixed to the inside of the sleeve. 
The pads, in conjunction with a plurality of vertically-aligned stiffened 
stays incorporated into the sleeve, apply balanced opposing forces to the 
sides of the patella, thereby restricting movement of the patella. 
U.S. Pat. No. 4,938,207 discloses a knee brace that applies variable 
support to the patella as a function of the position of the leg during 
dynamic exercise thereof. The knee brace has a system of inflatable 
chambers including four relatively small side chambers, two of which are 
configured to engage the medial side of the patellar circumference and two 
of which are configured to engage the lateral side of the patellar 
circumference. Each side chamber is in fluid isolation from the other, but 
is in fluid communication with a considerably larger remote chamber that 
is positioned against the thigh or calf away from engagement with the 
patella. The remote chamber serves as a fluid reservoir for its respective 
side chamber and each remote chamber is provided with a valve that enables 
selective addition of fluid to or withdrawal of fluid therefrom. 
When a leg having the brace of U.S. Pat. No. 4,938,207 mounted thereon is 
flexed at the knee joint, the thigh or calf compresses the remote 
chambers, thereby transferring a large volume of fluid into the respective 
side chambers. The infusion of fluid into the relatively small side 
chambers substantially increases the fluid pressure therein and 
correspondingly increases the force load they apply to the medial and 
lateral sides of the patella. Consequently, medial and lateral support for 
the patella is markedly increased when the leg is flexed. Conversely, when 
the leg is extended at the knee joint, the thigh or calf decompresses the 
remote chambers, thereby returning the fluid from the side chambers back 
to their respective remote chambers. Consequently, medial and lateral 
support for the patella is markedly decreased when the leg is extended. 
U.S. Pat. No. 4,378,009 discloses a knee brace having a single inflatable 
pneumatic pad in the shape of an elongated tube. The pad is selectively 
configured about the knee joint to circumscribe the entire patella and 
provide balanced compression forces thereto. 
U.S. Pat. No. 4,872,448 likewise discloses a knee brace employing a single 
inflatable pneumatic pad to restrict the movement of the patella. The 
pneumatic pad, however, has a slotted longitudinal opening formed therein 
that fits over the patella. Consequently, the pad engages only the medial 
and lateral sides of the patella, applying balanced opposing compression 
forces thereto. The pad permits distal and proximal vertical dislocation 
of the patella along the path of the longitudinal opening, while 
restricting medial and lateral horizontal dislocation of the patella. 
Despite the existence of braces in the prior art designed to stabilize the 
patella, a need continues for improved knee braces that more effectively 
stabilize the patella. Accordingly, it is an object of the present 
invention to provide a knee brace that satisfies this need. More 
particularly, it is an object of the present invention to provide a knee 
brace that resists undesirable patellar dislocation. It is another object 
of the present invention to provide a knee brace that biases and maintains 
the patella in a biomechanically correct position. It is yet another 
object of the present invention to provide such a knee brace, wherein the 
degree of bias is simply, effectively and selectively adjustable by the 
user. It is still another object of the present invention to provide a 
knee brace that is comfortable for the user. It is a further object of the 
present invention to provide a knee brace that does not overly restrict 
the mobility of the user. These objects and others are achieved by the 
invention described hereafter. 
SUMMARY OF THE INVENTION 
The present invention is a knee brace positionable on the knee joint of a 
user to resist dislocation of the patella from a desired position. The 
knee brace can also be used to selectively reposition and retain the 
patella in a biomechanically corrected position. The brace comprises a 
compliant sleeve formed from a relatively elastic material that is sized 
to enclose substantially the entire knee joint when the brace is mounted 
thereon. An anterior opening is optionally provided through the anterior 
face of the sleeve to circumscribe the patella and expose a portion of the 
patellar face. 
The brace further comprises an anterior cover overlying a portion of the 
anterior face of the sleeve. The anterior cover is likewise optionally 
provided with an anterior opening corresponding to the anterior opening of 
the sleeve which avoids covering the exposed portion of the patellar face. 
The anterior cover may be formed from the same elastic material as the 
sleeve, but is preferably formed from a relatively less elastic material. 
The anterior cover is fixedly attached along its perimeter to the 
underlying anterior face of the sleeve, thereby creating a pocket between 
the sleeve and cover. The pocket encloses and secures a pad in a 
prescribed position on the sleeve that circumscribes substantially all but 
a lower portion of the patella, and correspondingly all but a lower 
portion of the anterior openings in the sleeve and anterior-cover. 
The pad is a divided hollow bladder, enclosing a pair of arcuate-shaped 
chambers maintained in fluid isolation from each other. The chambers are 
substantially symmetrical, each having an elongated longitudinal segment 
in opposing, substantially corresponding alignment with the longitudinal 
axis of the sleeve. Each chamber also has a shortened transverse segment 
at the upper end of the longitudinal segment that curves inwardly toward 
the transverse segment of the opposing chamber in substantially transverse 
alignment with the longitudinal axis of the sleeve. The two chambers in 
combination define the configuration of the pad as an open loop 
substantially corresponding to, and circumscribing, the entire perimeter 
of the patella excluding, however, the inferior patellar apex. 
Accordingly, the pad has a substantially closed upper end and a 
substantially open lower end. The upper end, along with the medial and 
lateral sides of the pad, circumscribe the perimeter of a central opening 
in the pad, while a lower opening is provided at the lower end of the pad 
that adjoins the central opening. 
The chambers are provided with one or more selectively resealable valves 
and pumps, enabling selective fluid communication between the interior and 
exterior of the chambers for separately adding fluid into each chamber or 
withdrawing fluid from each chamber. The brace may also be also provided 
with one or more straps, wherein each strap has two ends selectively 
connectable to the sleeve so that the strap can be adjustably disposed 
along the sleeve in a circumferential or longitudinal direction. 
To operate the brace, the sleeve is placed over the knee joint of the user 
with the chambers at least partially deflated and the strap ends, if one 
or more straps are provided, free or loosely attached to the sleeve. The 
pad is aligned to circumscribe substantially all but the inferior apex of 
the patella, while the anterior openings of the sleeve and cover, if 
provided, are positioned over the patella with the patella exposed 
therethrough. The brace is rendered operable by inflating one or both of 
the chambers with a selected fluid, wherein the fluid is displaced into 
the chambers by means of the one or more release valves and pumps provided 
in association with the chambers. 
As each chamber inflates and expands, the preferably relatively inelastic 
anterior cover directs the expansion of the chamber in the direction of 
the patella causing the chamber to radially impinge against the 
circumference of the patella engaged thereby. If it is desired to securely 
retain the patella in its inherently natural position, both chambers are 
inflated to a similar pressure so that there is no inflation differential 
between them. The pad consequently exerts balanced radial forces on the 
circumference of the patella engaged thereby. The balanced radial forces 
maintain the patella in its natural position resistant to dislocation 
therefrom. 
If the natural position of the patella is biomechanically incorrect, 
however, due to an injury or chronic condition, it is often desirable to 
reposition and retain the patella in a biomechanically corrected position 
rather than its natural position. Accordingly, the chambers are 
selectively inflated to different pressures creating an inflation 
differential between them. The pad consequently exerts unbalanced radial 
forces on the circumference of the patella engaged thereby as a function 
of the inflation differential. The unbalanced radial forces reposition the 
patella to the corrected position and resist dislocation therefrom. 
The forces applied by the brace to the patella can be augmented by 
tightening one or more straps optionally provided along the sleeve against 
the patella in a desired configuration. Increasing or decreasing the 
tension of the straps correspondingly adjusts the level of force the strap 
applies to the patella. The strap tension is modified by repositioning the 
attachment points of the straps along the sleeve. 
The present invention will be further understood, both as to its structure 
and operation, from the accompanying drawings, taken in conjunction with 
the accompanying description, in which similar reference characters refer 
to similar parts.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring initially to FIG. 1, a conceptualized patella 100 of the right 
knee joint is shown, the patella of the left knee joint being 
substantially identical. The patella 100 is the treatment objective of the 
knee brace of the present invention and, accordingly, is a frame of 
reference for the structure and utility of the present knee brace. The 
patella 100 is defined as having a patellar face 102 and a substantially 
triangular perimeter 104. The perimeter 104 is further defined to include 
four segments, i.e., medial and lateral sides 106, 108, a superior base 
110 and an inferior apex 112. The medial and lateral sides and base 106, 
108, 110 are substantially linear and the apex 112 is substantially 
arcuate. 
Referring now to FIGS. 2 and 3, a knee brace of the present invention is 
shown and generally designated 10. The knee brace 10 is positioned on the 
right leg 12 of a user about the knee joint 14. The brace 10 comprises a 
sleeve 16 formed from a sheet of compliant material such as a natural or 
synthetic cloth, foam, elastomer, leather, or combination thereof. The 
sheet material is preferably relatively elastic as well as compliant, such 
that the sleeve 16 exerts a restorative force when stretched in 
substantially any direction. The preferred sheet material is a laminate of 
cloth-covered neoprene foam. 
The sleeve 16 is typically fabricated by cutting one or more flat patterns 
from a planar sheet of the selected material and combining the pattern or 
patterns in a manner readily apparent to the skilled artisan to preform 
the sleeve 16 in the configuration of a tube. The tubular preformed sleeve 
16 is mounted on the leg 12 by placing the foot 18 through the axial 
opening 20 of the sleeve and sliding the sleeve 16 up over the lower leg 
22 until the sleeve 16 snugly encloses the knee joint 14. The sleeve 16 
preferably has an anterior opening 24 formed therethrough that is 
positioned over the patella 100 exposing at least a portion of the 
patellar face 102. The restorative force of the elastic sheet material 
maintains the sleeve 16 in place about the knee joint 14. 
Although not shown, the sleeve can alternatively be configured as a wrap 
having two free ends prior to mounting, rather than preformed as a tube. 
The wrap configuration of the sleeve is mounted on the leg by drawing the 
two free ends around the knee joint, joining the ends, and securing them 
with straps or the like, thereby transforming the wrap to a tube when 
mounted on the leg. This embodiment of the sleeve likewise falls within 
the scope of the present invention. 
The brace 10 further comprises an anterior cover 26 fixedly attached along 
its perimeter to the anterior face 28 of the sleeve 16. The anterior cover 
26 is fixed in place by attachment means such as stitching 30 to form a 
closed anterior pocket 32 between the posterior face of the anterior cover 
26 and the anterior face 28 of the sleeve 16. The anterior cover 26 is 
preferably provided with an anterior opening 34 corresponding to the 
anterior opening 24 of the sleeve 16 which avoids covering the exposed 
portion of the patellar face 102. The profile of the anterior cover 26 
corresponds substantially to the profile of a pad 36 enclosed within the 
anterior pocket 32 between the overlying anterior cover 26 and the 
underlying sleeve 16. A longitudinal partition 38 is placed in the 
anterior pocket 32 extending downwardly from the anterior opening 24 to 
facilitate proper positioning of the lower end 40 of the pad 36 within the 
anterior pocket 32. The longitudinal partition 38 is preferably stitching 
joining the anterior cover 26 and sleeve 16 along the length of the 
partition 38. The anterior cover 26 is formed from a sheet of compliant 
material that may be substantially the same material as the sheet material 
of the sleeve 16, but is preferably a material that is relatively 
inelastic or at least substantially less elastic than the sheet material 
of the sleeve 16. In addition, the material of the anterior cover 26 also 
preferably has the external character of either a hook coupling or a loop 
coupling of a hook and loop fastener pair commonly termed VELCRO. The 
material of the anterior cover 26 most preferably has the external 
character of a loop coupling. As such, the material of the anterior cover 
26 can, for example, be a relatively inelastic weave of a synthetic cloth 
such as nylon or the like. 
Medial and lateral covers 42a, 42b are fixedly attached along their 
perimeter to the medial and lateral faces 44a, 44b, respectively, of the 
sleeve 16. Like the anterior cover 26, the medial and lateral covers 42a, 
42b are fixed in place by stitching 46a, 46b, respectively, to form closed 
medial and lateral pockets 48a, 48b, respectively, shown with reference to 
FIGS. 6A and 6B. The profiles of the medial and lateral covers 42a, 42b 
correspond substantially to the profiles of longitudinal stiffeners 50 
enclosed within the medial and lateral pockets 48a, 48b. The stiffeners 50 
are preferably formed from spiral metal stays and run longitudinally along 
substantially the entire length of the sleeve 16. Like the anterior cover 
26, the medial and lateral covers 42a, 42b are also formed from a sheet of 
compliant material that may be substantially the same material as the 
sheet material of the sleeve 16, but is preferably a material that is 
relatively inelastic or at least substantially less elastic than the sheet 
material of the sleeve 16. The material of the medial and lateral covers 
42a, 42b also preferably has the external character of either a hook 
coupling or a loop coupling, and most preferably of a loop coupling. 
It is also noted with reference to FIG. 2 that a pair of manual valve 
actuators 52a, 52b, cooperatively functioning with the pad 36 as will be 
shown, protrude through the anterior cover 26 from the interior of the 
pocket 32. Details of the pad 36 and its cooperative elements are 
described hereafter with reference to FIGS. 4 and 5. 
A preferred configuration of the pad 36 is described with specific 
reference to FIG. 4. The pad 36 is preferably formed from two continuous 
sheets of a film material. The film material is a highly-flexible, 
collapsible, fluid-impervious material. Materials exhibiting these 
characteristics include plastics, such as polyurethane, polyvinyl 
chloride, or the like. The pad 36 is constructed by overlaying one sheet 
atop the other and joining them together along their periphery using 
conventional means, such as r.f. welding, thereby forming a continuous 
peripheral seam 54 defining the outer perimeter of the pad 36 while 
maintaining a substantial void within the interior of the pad 36. The 
peripheral seam 54 outlines a substantially open-loop, horseshoe-shaped 
frontal profile of the pad 36 sized to circumscribe the anterior openings 
24, 34 of the brace 10, and correspondingly the patellar perimeter 104, in 
their entirety with the exception of the inferior patellar apex 112 and 
lower portions of the anterior openings 24, 34. Accordingly, the pad 36 
has a longitudinally-elongated, downwardly-tapered central opening 56 
formed therethrough to receive the patella 100. The pad 36 further has a 
lower opening 58 formed through its lower end 40 to provide clearance for 
the inferior patellar apex 112 as well as the infrapatellar bursa and the 
patellar tendon (not shown) extending downwardly from the apex 112, 
thereby minimizing discomfort to a user of the brace 10. 
The interior of the pad 36 bounded by the peripheral seam 54 is divided 
into two opposing fluid-tight pad chambers, a medial pad chamber 60a and a 
lateral pad chamber 60b. The medial and lateral pad chambers 60a, 60b are 
attached to each other at the upper end 61 of the pad 32 by means of a 
connective member 62 which is a continuation of the peripheral seam 54. 
The connective member 62 maintains the medial and lateral pad chambers 
60a, 60b in fluid isolation from each other. The medial and lateral pad 
chambers 60a, 60b are configured as substantial mirror images of each 
other. Accordingly, the medial pad chamber 60a and elements associated 
therewith are described hereafter, as being representative of both pad 
chambers 60a, 60b and elements associated therewith. Medial elements are 
designated with the suffix "a", whereas corresponding lateral elements are 
designated with the suffix "b". 
The medial pad chamber 60a has an elongated, arcuate, open-loop 
configuration corresponding to half of a horseshoe. Accordingly, the 
medial pad chamber 60a resembles an inverted "J" that substantially 
conforms to the entirety of the medial side 106 and a portion of the base 
110 of the patella 100 which abut the medial pad chamber 60a across the 
intervening sleeve 16. In the manner of an inverted "J", the medial pad 
chamber 60a has a substantially linear elongated longitudinal segment 63a 
extending from the lower end 40 to the upper end 61 of the pad 36 in 
substantially corresponding alignment with the longitudinal axis of the 
sleeve 16. The longitudinal segment 63a is configured to abut the medial 
side 106 of the patella 100. Also in the manner of an inverted "J", the 
medial pad chamber 60a also has a shortened arcuate transverse segment 64a 
at the upper end 61 of the pad 36 that curves inwardly toward the opposing 
chamber 60b in substantially transverse alignment with the longitudinal 
axis of the sleeve 16. 
A medial extension member 66a extends from the transverse segment 64a of 
the medial pad chamber 60a, having a manually operable medial release 
valve 68a, including the manual medial valve actuator 52a, mounted 
therein. A chamber port tube 70a extends between the interior of the 
medial extension member 66a and the interior of a medial pump chamber 72a 
associated with a medial pump 74a. The medial pump chamber 72a is a 
squeezable elastic bulb having good memory characteristics. The chamber 
port tube 70a has a passive one-way chamber valve 76a positioned on its 
lower end within the interior of the medial extension member 66a enabling 
selective fluid communication between the medial pad chamber 60a and the 
medial pump chamber 72a. The medial chamber valve 76a opens under 
sufficient fluid pressure in the direction of the medial pad chamber 60a, 
but is unresponsive to fluid pressure in the direction of the medial pump 
chamber 72a. Accordingly, the medial chamber valve 76a permits fluid flow 
exclusively in the direction of the medial pad chamber 60a from the medial 
pump chamber 72a. 
In addition to the medial pump chamber 72a, the medial pump 74a comprises a 
pump port tube 78a extending from the interior of the medial pump chamber 
72a out to the atmosphere. The pump port tube 78a has a passive one-way 
pump valve 80a positioned on its lower end within the interior of the 
medial pump chamber 72a enabling selective fluid communication between the 
medial pump chamber 72a and the atmosphere. The medial pump valve 80a is 
similarly configured to the medial chamber valve 76a to permit fluid flow 
exclusively in the direction of the medial pump chamber 72a from the 
atmosphere. Selective fluid communication between the medial pad chamber 
60a and the atmosphere is provided by the medial release valve 68a 
described hereafter with reference to FIG. 5. The medial release valve 68a 
comprises the medial valve actuator 52a having a widened portion 82a at 
its lower end fitting into a valve seat 84a. The medial release valve 68a 
is maintained biased in a closed position by a spring 86a, but can be 
opened by manually depressing the valve actuator 52a against the force of 
the spring 86a. 
The lateral pad chamber 60b, being a substantial mirror image of the medial 
chamber pad 60a, likewise has an elongated, arcuate, open-loop 
configuration corresponding to the half of the horseshoe opposing the 
medial pad chamber 60a. The lateral pad chamber 60b substantially conforms 
to the entirety of the lateral side 108 and a portion of the base 110 of 
the patella 100 which abut the lateral pad chamber 60b across the 
intervening sleeve 16. The lateral pad chamber 60b further has a 
substantially linear elongated longitudinal segment 63b and a shortened 
arcuate transverse segment 64b. A lateral extension member 66b extends 
from the transverse segment 64b of the lateral pad chamber 60b, having a 
manually operable lateral release valve 68b, including the manual lateral 
valve actuator 52b, mounted therein. A chamber port tube 70b extends from 
the interior of the lateral extension member 66b. Although a lateral pump 
is not shown in FIG. 4 in association with the lateral chamber 60b, it is 
understood that a lateral pump substantially identical to the medial pump 
74a extends from the lateral extension member 66b. 
It is noted that the medial and lateral pad chambers 60a, 60b are very 
large relative to the medial and lateral extension members 66a, 66b, 
respectively, insofar as the pad chambers 60a, 60b are the primary fluid 
reservoirs for the pad 36. The extension members 66a, 66b merely serve as 
flowpaths between the pad chambers 60a, 60b and their respective pumps 
74a, 74b and release valves 68a, 68b. Accordingly, substantially all of 
the fluid capacity of the pad 36 is in the medial and lateral chambers 
60a, 60b, which are both positioned in abutment with the patella 100 
across the sleeve 16. No additional chambers or fluid reservoirs in 
continuous fluid communication with the medial and lateral pad chambers 
60a, 60b are required for operation of the knee brace 10 as described 
hereafter. 
METHOD OF OPERATION 
Operation of the knee brace 10 is described with reference to FIGS. 6A, 6B, 
7 and 8. Referring initially to FIGS. 6A and 6B, the brace 10 is shown in 
an operable position on the right leg 12 achieved by positioning the 
sleeve 16 over the knee joint 14 with a portion of the patellar face 102 
exposed through the anterior opening 24 of the sleeve 16 and the patella 
100 circumscribed by the pad 36 with the exception of the inferior apex 
112. While positioning the sleeve 16 over the knee joint 14, the pad 36 is 
maintained substantially deflated. Once the sleeve 16 has been properly 
positioned, one or both of the pad chambers 60a, 60b are inflated with a 
fluid. The fluid can be a gas, liquid or gel, but is preferably a 
pneumatic fluid, and is most preferably ambient air. 
The medial pad chamber 60a is inflated, for example, by taking air into the 
medial pump chamber 72a through the pump valve 80a and squeezing the pump 
chamber 72a to pump the air into the pad chamber 60a through the chamber 
valve 76a. As the medial pad chamber 60a inflates and expands, the 
relatively inelastic anterior cover 26 overlying the medial pad chamber 
60a directs expansion of the pad chamber 60a in a radial direction having 
a substantially lateral component, thereby causing the medial pad chamber 
60a to exert a corresponding radial force having a substantially lateral 
component against the medial side 106 of the patella 100. If it is 
desirable to adjust the fluid pressure of the medial pad chamber 60a, and 
consequently the radial force exerted thereby, fluid can be released from 
the pad chamber 60a through the medial release valve 68a by manually 
depressing the valve actuator 52a. 
It is apparent from the above, that the lateral pad chamber 60b can be 
similarly inflated or deflated to exert an adjustable radial force having 
a substantially medial component against the lateral side 108 of the 
patella 100. 
Referring specifically to FIG. 6A, both pad chambers 60a, 60b are shown 
inflated to an equal fluid pressure such that no fluid pressure 
differential exists between them. When both chambers 60a, 60b are inflated 
equally, as shown here, the radial forces exerted by the two chambers 60a, 
60b on the medial and lateral sides 106, 108 of the patella 100 are 
balanced. Consequently, this balanced mode of operation is selected when 
it is desired to securely retain the patella 100 in its inherently natural 
position resistant to dislocation therefrom. 
Referring to FIG. 6B, the medial pad chamber 60a is shown inflated to a 
fluid pressure substantially greater than the fluid pressure of the 
lateral pad chamber 60b such that a substantial pressure differential 
exists between them. The medial pad chamber 60a correspondingly exerts a 
greater radial force on the medial side 106 of the patella 100, than the 
opposing radial force exerted by lateral chamber pad 60b on the lateral 
side 108 of the patella 100. Accordingly, the medial pad chamber 60a 
dislocates the patella 100 in a substantially lateral direction. This 
unbalanced mode of operation is selected when it is desired to correct the 
natural position of the patella 100 by repositioning and retaining the 
patella 100 in a biomechanically corrected position. 
It is apparent that the lateral pad chamber 60b can similarly be inflated 
to a substantially greater fluid pressure than the medial pad chamber 60a, 
if it is alternatively desired to dislocate the patella 100 in a 
substantially medial direction. It is further apparent that the degree of 
patellar dislocation in the lateral or medial direction can be selectively 
adjusted by adjusting the pressure differential between the medial and 
lateral pad chambers 60a, 60b. 
Augmentation of the forces applied by the chamber pads 60a, 60b to the 
patella 100 is provided by positioning one or more straps along the sleeve 
16 during either the balanced or unbalanced mode of operation. FIG. 7 
shows one embodiment of a strap configuration wherein a single full strap 
88 extends circumferentially around the patella 100 and sleeve 16. The 
strap 88 is provided with an attachment means along its length (not shown) 
such as a VELCRO coupling, preferably a hook coupling, which enables 
attachment of the strap 88 to the anterior, medial or lateral covers 26, 
42a, 42b on the sleeve 16 at any number of positions. As shown, the full 
strap 88 is positioned over the upper end 61 of the pad 36 at a selected 
tension, thereby applying a substantially orthogonal force along the 
entire length of the patellar base 110 that is directed inward relative to 
the knee joint 14. The orthogonal force effectively tilts the entire 
patellar base 110 inward as desired by the user. Increasing the tension of 
the strap 88 by drawing it tighter and reattaching it to the sleeve 16, 
increases the orthogonal force on the patellar base 110, thereby 
effectively increasing the inward tilt of the patellar base 110. It is 
apparent that the strap 88 can be similarly placed over the lower end 40 
of the pad 32 to tilt the patellar apex 112 inward. 
FIG. 8 shows another embodiment of a strap configuration wherein a single 
half strap 90 extends circumferentially around substantially half of the 
patella 100 and sleeve 16. Like the full strap 88, the half strap 90 is 
provided with an attachment means along its length (not shown) such as a 
VELCRO coupling, preferably a hook coupling, which enables attachment of 
the strap 90 to the anterior, medial or lateral covers 26, 42a, 42b on the 
sleeve 16 at any number of positions. As shown, the half strap 90 is 
positioned over only the medial transverse segment 64a of the pad 36 at a 
selected tension, thereby applying a substantially orthogonal force along 
the patellar base 110 to only the upper medial quadrant of the patella 
100. The orthogonal force is directed inward relative to the knee joint 
14, effectively tilting the upper medial quadrant of patella 100 inward as 
desired by the user. Increasing the tension of the strap 90 by drawing it 
tighter and reattaching it to the sleeve 16, increases the orthogonal 
force on the upper medial quadrant of the patella 100, thereby effectively 
increasing the inward tilt thereof. It is apparent that the strap 90 can 
be similarly placed over the upper lateral, lower medial or lower lateral 
quadrants to tilt them inward as desired. 
Although the knee brace of the present invention and its method of 
operation have been described above as applied to the right leg, it is 
apparent to the skilled artisan that the brace is readily adaptable for 
application to the left leg. Furthermore, in the preferred embodiment of 
the pad 36, as described above, each pad chamber 60a, 60b is provided with 
a separate pump 74a, 74b and release valve 68a, 68b. It is apparent, 
however, to the skilled artisan that within the scope of the present 
invention a single pump and release valve can be configured to 
individually service both pad chambers 60a, 60b. The pad chambers 60a, 60b 
are also described above as being attached to each other by the connective 
member 62. It is further apparent to the skilled artisan that within the 
scope of the present invention the connective member 62 can be eliminated, 
thereby physically separating the pad chambers 60a, 60b without altering 
the function of the pad 36. Finally, it is apparent to the skilled artisan 
that within the scope of the present invention, either one of the pad 
chambers 60a, 60b can be eliminated from the brace and the brace can 
effectively operate with a single pad chamber 60a or 60b, thereby applying 
a radial force to the patella in only one direction in accordance with an 
unbalanced mode of operation. 
While the particular knee brace shown and disclosed herein is fully capable 
of obtaining the objects and providing the advantages stated herein, it is 
understood that this brace is merely illustrative of a presently preferred 
embodiment of the invention and that other embodiments are possible within 
the scope of the present invention.