(12) United States Patent
`Hunter et al.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 8,333,723 B2
`Dec. 18, 2012
`
`US008333723B2
`
`(54)
`
`(75)
`
`KNEE BRACE WITH EXPANDABLE
`MEMBERS AND METHOD OF USING THE
`SAME
`
`Inventors: David J. Hunter, Vaucluse (AU); Glenn
`Colaco, Caringbah (AU); Dimitrije
`Stamenovic, Brookline, MA (US)
`
`(56)
`
`(73)
`
`Assignee: Trustees of Boston University, Boston,
`MA (US)
`
`(*)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`USC 154(b) by 49 days.
`
`(21)
`
`Appl. No.:
`
`12/668,673
`
`(22)
`
`(86)
`
`(87)
`
`(65)
`
`(60)
`
`(51)
`
`(52)
`
`PCT Filed:
`
`Jul. 18, 2008
`
`PCT No.:
`
`PCT/US2008/070494
`
`§ 371 (0X1)’
`(2), (4) Date:
`
`Jun. 3, 2010
`
`PCT Pub. No.: WO2009/012458
`
`PCT Pub. Date: Jan. 22, 2009
`
`Prior Publication Data
`
`US 2010/0241041A1
`
`Sep. 23, 2010
`
`Related U.S. Application Data
`
`Provisional application No. 60/950,713, ?led on Jul.
`19, 2007.
`
`Int. Cl.
`(2006.01)
`A61F 5/00
`U.S. Cl. ............... .. 602/13; 602/16; 602/23; 602/26
`
`(58) Field of Classi?cation Search .................. .. 602/ 13,
`602/16, 23427; 128/882, DIG. 20; 2/22,
`2/24
`
`See application ?le for complete search history.
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`6/1971 Rosman et a1. ............... .. 128/80
`3,581,741 A
`2/1989 McDavid, III
`. 128/80 C
`4,805,606 A
`9/1990 Grim et al. . . . . .
`. . . .. 602/16
`4,953,543 A *
`3/1991 Spademan
`5,002,045 A
`. 128/80C
`5,360,394 A * 11/1994 Christensen
`602/26
`5,415,625 A *
`5/1995 Cassford et al. . . . . . . .
`. . . .. 602/26
`
`5,458,565 A 10/1995 Tillinghast, III et al.
`5,545,911 A *
`8/1996 Otsuki et al. ......... ..
`
`602/26
`257/376
`
`5,797,864 A
`
`8/1998 Taylor . . . . . . . . .
`
`. . . .. 602/26
`
`5,823,981 A * 10/1998 Grim et al. . . . . . . . . .
`. . . .. 602/26
`5,865,166 A
`2/1999 Fitzpatrick et a1. ...... .. 128/117.1
`(Continued)
`
`W0
`
`FOREIGN PATENT DOCUMENTS
`WO 01/45600
`6/2001
`OTHER PUBLICATIONS
`
`Abbate et al., “Anthropometric Measures, Body Composition, Body
`Fat Distribution, and Knee Osteoarthritis in Women,” Obesity, vol.
`14, No. 7, pp. 1274-1281 (2006).
`(Continued)
`Primary Examiner * Michael A. BroWn
`(74) Attorney, Agent, or Firm * Sunstein Kann Murphy &
`Timbers LLP
`ABSTRACT
`(57)
`A knee brace (300) has a body (310) supporting ?rst, second,
`and third expandable members (330). When expanded, the
`?rst, second, and third expandable members are positioned on
`the brace body to provide a counteracting force to the adduc
`tion moment of the knee.
`
`45 Claims, 7 Drawing Sheets
`
`Lateral-anterior view
`
`Medial-anterior view
`
`(y-axis is oriented toward central line of a body)
`
`Smith & Nephew Ex. 1050
`IPR Petition - USP 8,377,129
`
`

`
`US 8,333,723 B2
`Page 2
`
`US. PATENT DOCUMENTS
`
`8/2000 Shirley .......................... .. 602/26
`6,110,138 A
`5/2001 Gildersleeve et a1.
`602/26
`6,238,360 B1
`1/2002 Gildersleeve et a1.
`602/26
`6,336,909 B2
`7/2003 Hotchkiss et al.
`602/26
`6,592,538 B1
`6,994,682 B2* 2/2006 Bauerfeind et al. ..
`602/26
`7,083,586 B2
`8/2006 Simmons et al.
`602/23
`7,198,610 B2
`4/2007 Ingimundarson et al.
`602/26
`2002/0077574 A1
`6/2002 Gildersleeve et al.
`602/16
`2006/0135900 A1
`6/2006 Ingimundarson et al.
`602/26
`2006/0135901 A1
`6/2006 Ingimundarson et al. .... .. 602/26
`2006/0135902 A1
`6/2006 Ingimundarson et al. .... .. 602/26
`2006/0135904 A1
`6/2006 Ingimundarson et al.
`602/26
`2006/0264793 A1 11/2006 Simmons et al. ............. .. 602/23
`
`OTHER PUBLICATIONS
`
`Andriacchi, “Dynamics of Knee Malalignment,” Orthopedic Clinics
`ofNorth America, vol. 25, No. 3, pp. 395-403 (1994).
`Basford et al., “Form May Be as Important as Function in Orthotic
`Acceptance: A Case Report,”Arch. Phys. Med. Rehabil., vol. 83, No.
`3, pp. 433-435 (2002).
`Cerejo et al., “The In?uence of Alignment on Risk of Knee
`Osteoarthritis Progression According to Baseline Stage of Disease,”
`Arthritis & Rheumatism, vol. 46, No. 10, pp. 2632-2636 (2002).
`Ding et al., “A longitudinal study of the effect of seX and age on rate
`of change in knee cartilage volume in adults,”Rheumatology; vol. 46,
`No. 2, pp. 273-279 (2007).
`Felson et al., “Osteoarthritis: New Insights. Part 1: The Disease and
`Its Risk Factors”, Annals ofInternal Medicine, vol. 133, No. 8, pp.
`635-646 (2000).
`Felson et al., “Osteoarthritis: New Insights. Part 2: Treatment
`Approaches,”Annals ofInternal Medicine, vol. 133, No. 9 pp. 726
`737 (2000).
`Felson et al., “Bone Marrow Edema and Its Relation to Progression of
`Knee Osteoarthritis,” Annals of Internal Medicine, vol. 139, No. 5
`(Part 1), pp. 330-337 (2003).
`Fredriks et al., “Nationwide age references for sitting height, leg
`length, and sitting height/height ratio, and their diagnostic value for
`disproportionate growth disorders,” Archives of Disease in Child
`hood, vol. 90, No. 8, pp. 807-812 (2005).
`Giori, “Load-shifting brace treatment for osteoarthritis of the knee: A
`minimum 2 1/2-year follow-up study,” J Rehabil. Res. Dev., vol. 41,
`No. 2, pp. 187-194 (2004).
`Horlick et al., “Valgus Knee Bracing for Medial Gonarthrosis,” Clin.
`Journal ofSport Med., vol. 3, pp. 251-255 (1993).
`Hunter et al., “TrapeZiometacarpal subluXation predisposes to inci
`dent trapeZiometacarpal osteoarthritis (OA): the Frarningham
`Study,” Osteoarthritis & Cartilage, vol. 13, No. 11, pp. 953-957
`(2005).
`Hunter et al., “The Association of Meniscal Pathologic Changes With
`Cartilage Loss in Symptomatic Knee Osteoarthritis,” Arthritis &
`Rheumatism, vol. 54, No. 3, pp. 795-801 (2006).
`HurwitZ et al., “The knee adduction moment during gait in subjects
`with knee osteoarthritis is more closely correlated with static align
`ment than radiographic disease severity, toe out angle and pain,”
`Journal ofOrthopaedic Research, vol. 20, No. 1, pp. 101-107 (2002).
`Jordan et al., “EULAR Recommendations 2003: an evidence based
`approach to the management of knee osteoarthritis: Report of a Task
`
`Force of the Standing Committee for International Clinical Studies
`Including Therapeutic Trials (ESCISIT),” Ann. Rheum. Dis., vol. 62,
`No. 12, pp. 1145-1155 (2003).
`Kirkley et al., “The Effect of Bracing on Varus Gonarthrosis,” Jour
`nal ofBone and Joint Surgery,vol. 81, No. 4, pp. 539-548 (1999).
`Komistek et al., “An in vivo analysis of the effectiveness of the
`osteoarthritic knee brace during heel-strike of gait,” Journal of
`Arthroplasty, vol. 14, No. 6, pp. 738-742 (1999).
`Kraus et al., “A Comparative Assessment of Alignment Angle of the
`Knee by Radio graphic and Physical Examination Methods,”Arthritis
`&Rheumatism, vol. 52, No. 6, pp. 1730-1735 (2005).
`Lawrence et al., “Estimates of the prevalence of arthritis and selected
`musculoskeletal disorders in the United States,” Arthritis & Rheu
`matism, vol. 41, No. 5, pp. 778-799 (1998).
`Lindenfeld et al., “Joint Loading With Valgus Bracing in Patients
`With Varus Gonarthrosis,” Clinical Orthopaedics & Related
`Research, vol. 344, pp. 290-297 (1997).
`MiyaZaki et al., “Dynamic load at baseline can predict radiographic
`disease progression in medial compartment knee osteoarthritis,”Ann.
`Rheum. Dis., vol. 61, No. 7, pp. 617-622 (2002).
`Morbidity & Mortality Weekly Report, “Arthritis Prevalence and
`Activity LimitationsiUnited States,” MM WR, vol. 43, No. 24, pp.
`433-438 (1994).
`Morbidity & Mortality Weekly Report, “Prevalence and Impact of
`Chronic Joint SymptomsiSeven States,” MM WR, vol. 47, No. 17,
`pp. 345-351 (1998).
`Najibi et a1 ., “The use of knee braces, part 1: Prophylactic knee braces
`in contact sports,”American Journal of Sports Medicine, vol. 33, No.
`4, pp. 602-611 (2005).
`Pollo et al., “Reduction of Medial Compartment Loads With Valgus
`Bracing of the Osteoarthritic Knee,” American Journal of Sports
`Medicine, vol. 30, No. 3, pp. 414-421 (2002).
`Sharma et al., “The Role of Knee Alignment in Disease Progression
`and Functional Decline in Knee Osteoarthritis,” JAMA, vol. 286, No.
`2, pp. 188-195 (2001).
`Schipplein et al., “Interaction between active and passive knee sta
`biliZers during level walking,” Journal of Orthopaedic Research, vol.
`9, No. 1, pp. 113-119 (1991).
`Tetsworth et al., “Malalignment and degenerative arthropathy,”
`Orthopedic Clinics ofNorth America, vol. 25, No. 3, pp. 367-377
`(1994).
`Todd et al., “NaproXen. A reappraisal of its pharmacology, and thera
`peutic use in rheumatic diseases and pain states,” Drugs, vol. 40, No.
`1, pp. 91-137 (1990).
`Wada et al., “Relationships among bone mineral densities, static
`alignment and dynamic load in patients with medial compartment
`knee osteoarthritis,” Rheumatology; vol. 40, No. 5, pp. 499-505
`(2001).
`European Patent Of?cer Andreas Lickel, Authorized Of?cer, Inter
`national Search ReportiInternational Application No. PCT/
`US2008/070494, dated Oct. 7, 2008 (5 pages).
`The International Bureau of WIPO Philippe Becamel, Authorized
`Of?cer, International Preliminary Report on Patentability (with
`Written Opinion of theInternational SearchingAuthority)iInterna
`tional Application No. PCT/US2008/070494, dated Jan. 19, 2010 (10
`pages).
`
`* cited by examiner
`
`

`
`US. Patent
`
`Dec. 18, 2012
`
`Sheet 1 of7
`
`US 8,333,723 B2
`
`1
`I
`l
`|
`l
`l
`l
`l
`l
`I
`l
`l
`‘J
`
`lr-----———--—--r
`
`110
`
`L____________.|
`
`FIG. 1A
`
`

`
`US. Patent
`U.S. Patent
`
`Dec. 18, 2012
`Dec. 18,2012
`
`Sheet 2 of7
`Sheet 2 of7
`
`US 8,333,723 B2
`US 8,333,723 B2
`
`140
`0 4 1
`
`

`
`US. Patent
`
`Dec. 18, 2012
`
`Sheet 3 of7
`
`US 8,333,723 B2
`
`)
`
`FIG. 2
`
`

`
`US. Patent
`
`Dec. 18, 2012
`
`Sheet 4 of7
`
`US 8,333,723 B2
`
`Lateral-anterior view
`
`Medial-anterior view
`
`(y-axis is oriented toward central line of a body)
`
`FIG. 3
`
`

`
`US. Patent
`
`Dec. 18, 2012
`
`Sheet 5 of7
`
`US 8,333,723 B2
`
`300 x
`
`310
`
`340
`
`340
`
`Inside View
`
`Cross-Section
`
`Outside View
`
`FIG. 4
`
`

`
`US. Patent
`
`Dec. 18, 2012
`
`Sheet 6 of7
`
`US 8,333,723 B2
`
`520 X
`
`510
`
`330
`
`(Aternative
`Embodiment)
`
`352
`\
`
`375
`
`)
`
`(Aternative
`Embodiment)
`
`375
`
`350
`
`‘M
`
`FIG. 5B
`
`

`
`US. Patent
`
`Dec. 18, 2012
`
`Sheet 7 of7
`
`US 8,333,723 B2
`
`FIG. 6A
`
`F2
`
`F1
`
`FIG. 6B
`
`

`
`US 8,333,723 B2
`
`1
`KNEE BRACE WITH EXPANDABLE
`MEMBERS AND METHOD OF USING THE
`SAME
`
`PRIORITY
`
`This patent application claims priority from US. provi
`sional patent application Ser. No. 60/950,713, ?led Jul. 19,
`2007, and entitled “Knee Brace With Expandable Members
`and Method of Using the Same”, the disclosure of Which is
`incorporated herein, in its entirety, by reference.
`
`FIELD OF THE INVENTION
`
`The invention generally relates to knee braces and, more
`particularly, the invention relates to knee braces constructed
`to provide a counteracting force to the adduction moment or
`abduction moment of the knee.
`
`BACKGROUND OF THE INVENTION
`
`Affecting an estimated thirty percent of adults over age 55,
`knee osteoarthritis is one of the most frequent causes of loWer
`limb disabilities. Unfortunately, the incidence of knee
`osteoarthritis in the United States, Europe, and other regions
`is expected to rise as populations age.
`Safe and effective treatments of this disease are limited.
`For example, a number of current therapeutic modalities
`focus primarily on reducing pain and improving joint func
`tion by means of non-speci?c, symptomatic agents, such as
`non-steroidal anti-in?ammatory drugs (NSAIDs) and COX-2
`inhibitors. Undesirably, such agents are associated With high
`rates of adverse events. Moreover, these drugs rarely com
`pletely relieve symptoms. Many individuals With knee
`osteoarthritis thus ultimately require a total knee replace
`ment.
`The symptoms of knee osteoarthritis often are described as
`mechanicalithey occur With activity. Despite the above
`noted shortcomings of drug therapy, attempts to ameliorate
`the forces in the knee With braces have proven effective in
`relieving symptoms. Clinically effective prior art braces,
`hoWever, often are too bulky to comfortably Wear for long
`periods, and dif?cult to Wear underneath clothing.
`
`SUMMARY OF THE INVENTION
`
`In accordance With one embodiment of the invention, a
`knee brace has a body supporting ?rst, second, and third
`expandable members. When expanded, the ?rst, second, and
`third expandable members are positioned on the brace body to
`provide a counteracting force to the adduction moment of the
`knee.
`When in use, the ?rst and third expandable members illus
`tratively are positioned to engage the interior part of the leg
`above and beloW the knee, While the second expandable
`member illustratively is positioned to engage the lateral part
`of the knee. Moreover, the brace also may have a hinge
`coupled With the second expandable member. Among other
`things, the hinge may have a stationary portion contacting the
`second expandable member, and a pivoting portion having a
`gel material that contacts the knee (When in use).
`In illustrative embodiments, the body has a main portion
`formed of a ?exible material (e.g., neoprene) and at least one
`nylon strap supporting one of the expandable members.
`Moreover, the ?rst, second, and third expandable members
`each may include an in?atable bladder. The expandable mem
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`bers also may be ?uidly connected and have a valve for
`controlling ?uid ?oW (e.g., air) to each of them.
`In accordance With another embodiment of the invention, a
`method of stabiliZing a knee ?rst provides a knee brace hav
`ing a body supporting ?rst, second, and third expandable
`members, and then positions the knee brace about the knee.
`Speci?cally, When positioned, the ?rst and third expandable
`members are positioned on the interior portion of the leg
`above and beloW the knee, While the second expandable
`member is positioned on or very near to the lateral portion of
`the knee. The ?rst, second, and third expandable members
`cooperate in this manner to provide a counteracting force to
`the adduction moment of the knee When expanded.
`In accordance With additional embodiments of the present
`invention, a knee brace may also include a strap portion
`secured to a main portion. The main portion may be position
`able over a subject’s knee. The strap portion may have a
`plurality of expandable members (e.g., a ?rst, second, and
`third expandable member) that provide a counteracting force
`to an adduction moment of the knee. For example, the
`expandable members may be in?atable bladders and provide
`the counteracting force When expanded.
`The counteracting force may include three individual
`forces applied to the knee. For example, the ?rst expandable
`member may apply a ?rst force to the interior part of the leg
`above the knee. The second expandable member may apply a
`second force to the exterior part of the leg at the knee. Lastly,
`the third expandable member may apply a third force to the
`interior part of the leg beloW the knee.
`In accordance With still further embodiments, the knee
`brace may also include a hinge member located on the strap
`member. The hinge member alloWs subject to bend the knee
`and may be coupled With the second expandable member. The
`hinge member may include a stationary portion that contacts
`the second expandable member and a pivoting portion that
`pivots Within the stationary portion. The pivoting portion may
`also include a gel material that contacts the knee When in use.
`In accordance With additional embodiments of the present
`invention, a knee brace may include a body portion, a ?rst
`expandable member, a second expandable member, and a
`third expandable member. Each of the expandable members
`may be positioned on the body portion to provide a force on
`the knee. For example, the ?rst expandable member may
`apply a ?rst force to the medial part of the leg above the knee,
`the second expandable member may provide a second force to
`the lateral part of the leg at the knee, and the third expandable
`member may provide a third force to the medial part of the leg
`beloW the knee. The ?rst, second, and third forces may com
`bine to counteract an adduction moment of the knee.
`In accordance With further embodiments, the knee brace
`may also include a strap member secured to the body portion.
`The strap member may support and mechanically connect the
`?rst, second, and third expandable members. The strap mem
`ber may also have a non-elastic outer layer that prevents the
`?rst, second, and third expandable members from ballooning
`outWards.
`In accordance With another embodiment of the present
`invention, a method for counteracting an adduction moment
`in the a knee can include positioning a knee brace over a knee
`having an adduction moment, and in?ating a ?rst, second, and
`third expandable members on the knee brace. In addition to
`the expandable members, the knee brace may also have a
`body portion. The in?ated ?rst, second, and third expandable
`members may each provide a force that, together, counteract
`the adduction moment of the knee. The expandable members
`may be in?ated to a pressure that is dependent upon the user’ s
`level of activity.
`
`

`
`US 8,333,723 B2
`
`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Those skilled in the art shouldmore fully appreciate advan
`tages of various embodiments of the invention from the fol
`lowing “Description of Illustrative Embodiments,” discussed
`With reference to the drawings summarized immediately
`beloW.
`FIG. 1A schematically shoWs a human leg With malaligned
`knee that can be treated in accordance With illustrative
`embodiments of the invention.
`FIG. 1B schematically shoWs the skeletal structure of a
`human leg With a varus malaligned knee and the skeletal
`structure of a leg With a valgus malaligned knee.
`FIG. 2 schematically shoWs a generalized method of treat
`ing the malaligned knee shoWn in FIG. 1 by applying forces
`from in?atable members at the indicated sites.
`FIG. 3 schematically shoWs a knee brace produced in
`accordance With illustrative embodiments of the invention.
`FIG. 4 schematically shoWs additional use of the knee
`brace shoWn in FIG. 3, including additional details of the
`hinge member.
`FIG. 5A schematically shoWs additional detail of the strap
`member and in?atable member, in accordance With illustra
`tive embodiments of the present invention.
`FIG. 5B schematically shoWs a cross-section and addi
`tional details of the hinge shoWn in FIG. 4, in accordance With
`embodiments of the present invention
`FIGS. 6A and 6B schematically shoW higher stress areas of
`the knee brace shoWn in FIGS. 2-4.
`
`DESCRIPTION OF ILLUSTRATIVE
`EMBODIMENTS
`
`In illustrative embodiments, a knee brace has a plurality of
`expandable members selectively positioned to provide a
`counteracting force to the adduction moment of a malaligned
`knee. To that end, the knee brace has a body supporting ?rst,
`second, and third expandable members that apply force to the
`leg in a manner that counteracts the adduction moment.
`Details of illustrative embodiments are discussed beloW.
`FIGS. 1A and 1B schematically shoW human legs With
`malaligned knees that can be treated in accordance With illus
`trative embodiments of the invention. As shoWn in FIG. 1A,
`the leg on the left (i.e., the person’s right leg) has a signi?cant
`adduction moment, While the other leg appears approxi
`mately normal/neutral. Speci?cally, any shift from neutral or
`collinear alignment of the hip, knee, and ankle affects load
`distribution at the knee. The load-bearing axis is represented
`by a line draWn from the center of the femoral head to the
`center of the ankle. In a varus deformed knee (i.e., as shoWn
`in FIG. 1B), this line 120 passes medial to the knee center 110
`to create an adduction moment arm, Which increases the force
`across the medial compartment 160. In a valgus deformed
`knee, Which is opposite to a varus deformed knee, the load
`bearing axis 130 passes lateral to the knee center 110, and the
`resulting abduction moment arm increases the force across
`the lateral compartment 170.
`Perhaps one of the clearest Ways to visualiZe the impact of
`the adduction and abduction moments is in relation to the
`spacing of the knee. In a typical, healthy knee, the spacing
`betWeen the femur 140 and the tibia 150 Within the knee is
`primarily uniform. In other Words, the space/ gap betWeen the
`femur 140 and tibia 150 are substantially the same Within the
`medial compartment 160 and the lateral compartment 170.
`HoWever, When the knee is malaligned (e.g., varus or valgus
`malalignment), the spacing may change and alter the load
`Within the knee.
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`As shoWn in FIGS. 1B, When the knee suffers from a varus
`malalignment, the adduction moment reduces the space/ gap
`betWeen the femur 140 and the tibia 150 Within the medial
`compartment 160 and increases the spacing/ gap Within the
`lateral compartment 170. Conversely, in a valgus malaligned
`knee, the abduction moment decreases the space/ gap Within
`the lateral compartment 170 and increases the space/ gap
`Within the medial compartment 160. The space/ gap reduction
`in the respective compartments (e. g., the medial compartment
`160 in the varus knee and the lateral compartment 170 in the
`valgus knee) increases the load and forces Within the com
`partments. The increased load and forces, in turn, cause the
`symptoms described above (e. g., pain, loss of mobility,
`increased Wear on the bones and cartilage, etc.). As described
`herein, various embodiments of the present invention provide
`forces on the knee that counteract the adduction moment.
`Illustrative embodiments, thus, counteract the load/ forces
`Within the medial and lateral compartments and return the
`spacing to a substantially normal level (e. g., increase the
`spacing/ gap in the medial compartment 160 and reduce the
`spacing in the lateral compartment 170) in a varus knee.
`The normal range for alignment differs depending on the
`study. For example, in many studies, neutral (normal) align
`ment is 1 degree varus (range 0-2 degrees). With increasing
`osteoarthritis of the medial compartment, the knee becomes
`increasingly varus (mean 3 degrees). Among varus knees, the
`meaniSD severity of varus Was 3.13:1.25 degrees (range
`1.00-5.00 degrees), in K/L grade 0-l knees, 3.04:1.95
`degrees (range 100-800 degrees), in grade 2 knees, and
`4.34126 degrees (range l.00-l0.00 degrees), in grade 3
`knees (P not signi?cant for grade 0-l versus grade 2 knees;
`P:0.03 for grade 2 versus grade 3 knees).
`Malalignment provides only a static impression of the
`mechanical forces being imparted on the j oint in one plane. To
`appropriately determine these forces in more than one plane
`often requires 3-dimensional kinematic analysis. During the
`stance phase of gait, the force acting at the foot during gait
`passes medial to the center of the knee joint. The perpendicu
`lar distance from the line of action of this force and the center
`of the knee joint is the lever arm of this force. This force
`combined With this lever arm produces a moment that adducts
`the knee joint. This moment can be substantial and provide a
`major contribution to the total loading across the knee joint,
`Which is usually labeled the adduction (or external varus)
`moment at the knee. The mean maximum magnitude of the
`adduction moment (M) during normal gait is approximately
`3.3 percent body Weight (W) times height (h) and is greater
`than either of the moments tending to ?ex or extend the knee.
`Studies of patients With medial knee osteoarthritis shoW that
`they have, on average, a higher M (4.2 percent W><h) than
`those Without osteoarthritis.
`Accordingly, illustrative embodiments create a force dis
`tribution around the knee that counterbalances this difference
`in M (referred to as AM) betWeen a knee With osteoarthritis
`and a normal knee, i.e., AM:0.9 percent W><h. One study, for
`example, demonstrated the peak knee adduction moment in
`persons With moderate to severe osteoarthritis Was 5.3 percent
`W><h (range 0.4-8.4 percent) versus those With mild osteoar
`thritis 3.5 percent (1.1-7.4 percent), With a p-value for differ
`ence that Was 0.06. In persons Without osteoarthritis, HurWitZ
`population Would suggest the peak knee adduction moment is
`3 percent W><h. This translates to a higher maximum reaction
`force on the medial compartment by 25 percent over normal
`values in those With medial knee osteoarthritis.
`Illustrative embodiments of the invention counterbalance
`the adduction moment by exerting forces on three strategic
`points along the leg. To that end, FIG. 2 schematically shoWs
`
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`US 8,333,723 B2
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`5
`these forces, in Which forces F1, Which are exerted in an
`outward direction above and below the knee, substantially
`equal the force F2, Which is exerted substantially at the knee
`and in an inWard direction (i.e., in a direction that is opposite
`to the forces F1). For example, the forces F1 illustratively act
`an equal distance d from the point of application of the force
`F2. The moment produced by these forces that together coun
`terbalance the abduction moment therefore equals the prod
`uct of F1 and distance d. HoWever, since illustrative embodi
`ments of the knee brace are designed to counterbalance only
`the difference in that moment (also referred to as “delta M”,
`Which is equal to 0.9 percent W><h), it folloWs that:
`
`To those ends, in accordance With illustrative embodi
`ments, the forces F1 and F2 are applied by means of a system
`of expandable members 14, such as in?atable latex bladders
`330 (also identi?ed by reference number “14”), over pre
`scribed contact areas to Which the forces F1 and F2 point,
`respectively, in the ?gures. FIGS. 3 and 4 schematically shoW
`a right leg knee brace having such members.
`Speci?cally, as shoWn in those ?gures, the knee brace 300
`has a body 310 forming a plurality of straps 320 supporting
`the bladders 330 (only schematically shoWn), and a hinge 340
`for facilitating movement. In illustrative embodiments, the
`portion of the body 310 having no bladders 330 is formed
`simply from a ?exible material, such as neoprene. The knee
`brace 300 may also have an opening 335 located on the
`anterior part of the brace 300. When the brace 300 is in use,
`the opening 335 may be positioned over the knee cap to
`ensure proper positioning of the brace 300.
`As shoWn in FIG. 5A, the portions of the body 310 having
`the bladders 330 producing force F1, hoWever, have a more
`complex arrangement. In particular, those portions of the
`body 310 have a plurality of layers starting With an inner,
`relatively soft, pliable material layer 510 that removably
`adheres to the skin. For example, this inner layer 510 may be
`formed from neoprene. The next adjacent layer includes the
`in?atable bladder, Which should ?xedly adhere to neoprene.
`Among other things, the in?atable bladder 330 may take the
`form of a latex balloon. Finally, the knee brace 300 has an
`exterior, relatively non-elastic material layer 520 (e. g., nylon)
`that ?rmly resists outWard expansion of the bladder. Conse
`quently, rather than increasing the outer diameter of the brace
`10, expansion of the bladder 330 at that point should substan
`tially reduce the inner diameter of the brace 10.
`The portion of the body 310 applying the inWardly directed
`force F2 has an even more complex arrangement than the
`other portions described above. Speci?cally, this portion is
`con?gured to permit the leg to freely pivot Without compro
`mising the structural integrity of the bladder. To that end, in
`addition to a soft pliable layer 510, in?atable bladder 330, and
`outer non-elastic layer 520, the knee brace 300 may also
`include the above noted hinge 340 that extends through the
`soft pliable layer 510 (e.g., the neoprene layer) and the non
`elastic layer 520 (e. g., the nylon layer). Generally, the hinge
`340 may have a movable portion and a ?xed portion (relative
`to the knee) radially inWard of the movable portion. The
`movable portion may be connected With the soft inner layer
`(or body portion 310), While the ?xed portion may be con
`nected With the next succeeding layer; namely, the in?atable
`bladder 330. The strap member 320 or non-elastic material
`may help resist outWard expansion of the bladder 330.
`As shoWn in FIGS. 4 and 5B, the hinge 340 may include a
`condylar pad 360, protrusion 370, and coupling 350. The
`condylar pad 360 removeably adheres the lateral portion of
`the knee at the location of F2 and may be made from a soft
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`silicon gel that has a consistency analogous to that of a baby
`teething ring. Although the condylar pad 360 may rotate With
`respect to the coupling 350, the condylar pad 360 should not
`rotate relative to the knee (e.g., it should maintain contact and
`move With the knee).
`Protruding from the lateral side of the condylar pad 360,
`the hinge 340 has a protrusion 370 that engages With the
`coupling 350. The protrusion 370 can be any number of
`structures including, but not limited to, an annular ring or a
`series of post members. As mentioned above, the protrusion
`370 engages With the coupling 350. To that end, the coupling
`350 can have a track 355, in Which the protrusion 370 may sit.
`To prevent disengagement, the protrusion 370 may have a
`thicker portion 375 toWards the end of the protrusion 370. In
`such embodiments, the protrusion 370 may be “snapped” into
`the track 355 and the thicker portion 375 Will prevent the
`protrusion 370 and, thus, the condylar pad 360 from disen
`gaging from the coupling 350. Once assembled, the condylar
`pad 360 and protrusion 370 can move relative to the coupling
`350.
`To facilitate the application of force F1 and attachment
`With the in?atable bladder 330, the hinge 340 can have arm
`member(s) 380 that extend radially outWard (e.g., above and
`beloW) from the hinge 340. As shoWn in FIG. 5B, the in?at
`able bladder 330 can be located beloW these arm member(s)
`380. As the bladder 330 is in?ated (e.g., to exert force F1 on
`the knee), the arm member(s) 380 prevent the bladders 330
`from ballooning out and ensure that the force is applied to the
`knee.
`As one may expect, the presence of the in?atable bladders
`330 under the arm member(s) 380 may tend to lift the condy
`lar pad 360 off the knee When the bladders 330 are in?ated.
`HoWever, in illustrative embodiments of the present inven
`tion, the body portion 310 and the strap members 320 prevent
`this from happening. In particular, because the body portion
`310 and the strap members 320 are kept tight on the subject,
`the tWo components are able to keep the condylar pad 360 in
`contact With the knee at all times. Additionally, as mentioned
`above, the body portion 310 and the strap members 320 also
`help prevent the bladders 330 from ballooning out and help
`the knee brace 300 effectively apply the force F2 to the knee.
`As shoWn in FIG. 5B, the coupling 350 can be an annular
`ring having an opening 352. The opening 352 provides the
`user With access to the in?atable bladder 330 (e. g., to in?ate
`the bladder(s) 330). For example, the knee brace may have a
`tube (not shoWn) extending from the in?atable bladder(s) 330
`to the opening 352. The user may then in?ate the bladder(s)
`330 in any of the manners described beloW (e. g., hand pump,
`electric pump, bloWing into a one-Way valve, etc.).
`As mentioned above, the in?atable bladder 330 may be
`located beloW the arm member(s) 380. In alternative embodi
`ments, the in?atable bladder(s) 330 may be located above the
`arm member(s) 380 (shoWn in dashed lines in FIG. 5B). In
`such embodiments, When in?ated, the bladder(s) 380 Will
`exert a force on the arm member(s) 380 that is directed
`toWards the knee. The arm members 380 Will, in turn, trans
`late the force to the hinge 340 and condylar pad 360. In such
`embodiments, the hinge 340 and condylar pad 360 apply the
`force F2 to the lateral portion of the knee and there may be no
`direct contact betWeen the in?atable bladder(s) 330 and the
`skin.
`It is important to note that the number and style of
`bladder(s) 330 used at this location can vary. For example,
`some embodiments of the knee brace 300 may only have a
`single annular bladder 330 that surrounds the hinge 340.
`Alternatively, the knee brace 300 may have one or more arm
`member(s) 380 (e.g., as described above) and a single bladder
`
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`US 8,333,723 B2
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`7
`330 located above and/or below each of the arm member(s)
`380. For example, if the hinge 340 has two arm members 380
`(e. g., one extending up toward the subj ect’s hip and one
`extending down towards the subject’s foot), the knee brace
`300 can have an in?atable bladder 330 located above and/or
`below each of the two arm members 380. Alternatively, the
`hinge 340 can have four arm me