Adaptive knee braces and methods of their operation

Abstract

An adaptive knee brace 100 for applying tensile / compressive, shear, or rotational torque force comprising: upper and lower strap portions 10,16 and a linkage 20 joining the strap portions for articula

Description

[0001] This invention relates to knee braces, in particular to adaptive knee braces for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, and to associated methods of operating such adaptive knee braces. BACKGROUND

[0002] Currently, there is no known cure for Knee Osteoarthritis (KOA). Most of the available treatments focus on symptom reduction and improvement of physical function, during the early stages. Presently, end stage treatment is surgical with joint replacement.

[0003] Mechanical unloading at an early stage has been shown to be an effective solution. However, the current options are limited, invasive and costly. High tibial osteotomy is a surgical intervention when the mechanical alignment of the limb is changed to offload the portion of the knee that has OA. This invasive intervention highlights that offloading works.

[0004] Knee braces which are non-invasive and non-surgical show potential effectiveness. Knee braces are designed to redistribute loads within the knee as per high tibial osteotomy, but without the surgery. This alleviates KOA symptoms by providing pain relief for a short period of time; their regular use delays / minimises the need for surgical intervention.

[0005] Surgical knee interventions are not recommended for young patients or those who are more active. In order to reduce the possibility of needing future surgery, providing such patients with a pain-relief device that still allows them to exercise and play sports will be beneficial. This includes individuals, particularly athletes with previous knee injuries.

[0006] It has been found that KOA worsens with age, which is why the incidence is so high among the elderly. Many such patients prefer treatment options with immediate benefits rather than long-term solutions. For instance, Total knee replacement (TKR) intervention and the associated hospital stay are not worth the risk when other alternatives exist. Therefore, a device that relieves their pain and facilitates their daily activities while reducing the need for frequent physician visits would be particularly appealing to this demographic.

[0007] Aside from surgical intervention, biomechanical interventions are the only treatments proven to reduce or control pain, improve function, and improve quality of life for KOA patients. One such biomechanical intervention is the use of prescribed insoles. Another is the use of an unloading knee brace.

[0008] Known knee braces typically function by a three-point loading / bending mechanism that relies on rigid fixation to the thigh and calf. This mechanical coupling of the brace with the limb results in discomfort, makes it difficult to use, and eventually produces slippage leading to a reduction in mechanical function and a lack of compliance by most of the patients.

[0009] The market for unloading knee braces has considerably increased in recent years, according to the increasing disease trend. For example, in 2020, the pooled global incidence of knee OA was 203 per 10,000 person-years in individuals aged 20 and over. Correspondingly, there are around annual 86,7 million individuals (20 years and older) with incident knee OA worldwide. In the UK approximately 4.7 million people >40 years had KOA in 2020 (14% of the population in that age group) and in US an estimated 15 million people >40 years have KOA.

[0010] Which specific unloading knee brace is recommended for a particular patient depends on many different factors and will ultimately be the corresponding clinician’s choice.

[0011] Although there is a variety of different bracing types, manufacturers, and products currently available on the market, there is no brace that can respond to the activity being performed by the person and that can be easily adapted to active lifestyles. Some known braces allow the user to adjust the strength of the force to be applied manually; however, the force will be applied uniformly until the patient re-adjusts the brace. Because of this, the patient is not able to adapt to the gait cycle as well as specific actions that they may perform during which the knee force changes (e.g. squatting, running, kneeling, etc.). To adapt a brace to these activities, the user may have to readjust the brace again, which in some cases requires special tools.

[0012] One known knee brace, the OA knee brace from Orthomen and as used by the NHS in the UK, is designed for reducing knee pain caused by unicompartmental osteoarthritis and comprises a 3-point leverage system. This is a constant unloader type of device (i.e. it provides a constant unloading force across the knee joint). The amount of unloading force is adjustable through use of an external tool.

[0013] Another similar known constant offloader knee brace, the Unloader One X®, from Ossur, is designed for pain relief and may improve mobility, and also comprises a 3-point leverage system. The unloading force is constant, but may be adjusted.

[0014] Dynamic unloading knee braces are typically adjusted using several mechanisms. One common method involves adjustable straps, such as Velcro(RTM) or buckle straps, which can be tightened or loosened to change the force applied to the knee joint. Many braces also feature dials or ratchet systems that control the tension in the brace's structure. These mechanisms allow for incremental adjustments and may include locking features to maintain the set tension.

[0015] Some braces also utilize spring mechanisms, where the tension can be adjusted to increase or decrease the unloading force. Depending on the brace model, some basic tools might be needed for these adjustments, such as a screwdriver, Allen wrench, or an adjustable wrench.

[0016] The Custom Adjustable OA Defiance® knee brace, from Enovis / DJO global, is designed to provide ligament stability and support for moderate to severe levels of KOA in active OA patients. It is custom made for a particular patient, and comprises a 4-point leverage system that provides a constant unloading force. Although the unloading force is constant during use, it may be adjusted, for example by using hinge adjustments to modify the hinge angle, thereby altering the force application.

[0017] The Osteoarthritis Unloading Knee Brace, from Superior Braces, is designed to reduce pressure inside the knee joint. Valgus &varus adjustment is included to fit to a particular individual's alignment. This is another constant unloader type of device, in which the unloading force is constant during use, but which may be adjusted through use of an external tool.

[0018] The OA NANO™ knee brace, from Enovis / DJO global, is designed for pain relief and to provide either a low or a high off-loading force across the knee joint, for mild to moderate KAO. The amount of offloading force varies with the brace flexion angle due to the mechanical arrangement of the constituent 4-points leverage system.

[0019] The Duo knee brace from Breg is designed for pain relief and for improving knee function for daily activities. The amount of unloading force applied across the knee joint is dynamic, varying with the brace flexion angle due to the mechanical arrangement of the constituent dynamic loading hinge.

[0020] Another known knee brace, the Levitation 2, from Spring L.Tech, is designed to reduce pain across the entire knee joint by application of torque forces during flexion and extension of the knee / brace. This does not directly apply an unloading force across the knee joint as per the other known knee braces described above. The torque forces may be adjusted through customisation of the mechanical spring power.

[0021] These known brace technologies demonstrate that offloading knee braces could provide a solution, but current offloading braces are only able to provide this for a short period of time due to mechanical coupling issues (slippage) and pressure (pain) due to the mechanical coupling needing to be very tight.

[0022] There is currently no knee brace on the market that adapts its loading profile to the activity of the user. Also, there is no brace that accommodates for the inevitable slippage.

[0023] Accordingly, there remains a need to provide a knee brace that is adaptive; able to adjust to changing requirements, for example in real-time and automatically, responsive to the user's needs or movements. Moreover, the need extends also to providing a knee brace that provides for implementation of both a manual and an automatic mode, thus offering the flexibility for users to choose between automatic control, as above, and manual control, where they can adjust the settings themselves.

[0024] The present invention seeks to eliminate these inconveniences by automatically effecting these adjustments, providing dynamically adjustable, ‘adaptive’, offloading forces. The invention seeks to provide a long-term use orthopaedic unloading brace, offering simplicity in fitting and usage without the need for specialized training or assistance.

[0025] The knee brace of the invention seeks to provide a transformative solution for individuals with chronic knee issues, with an ability to enhance mobility, improve daily activities, and enable individuals to regain an active and pain-free lifestyle. The brace provides an alternative to invasive interventions or dependence on pain medications. It offers a non-invasive and non-pharmaceutical option for managing knee discomfort. BRIEF SUMMARY OF THE DISCLOSURE

[0026] In accordance with a first aspect of the present invention, there is provided an adaptive knee brace for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, the brace comprising: an upper strap portion for strapping to a user’s leg above the knee; a lower strap portion for strapping to the user’s leg below the knee; a linkage joining the upper strap portion to the lower strap portion for articulation of the upper strap portion relative to the lower strap portion; a biasing assembly comprising: a biasing force generator comprising first and second portions arranged to impart a biasing force on the linkage to bias the upper strap portion relative to the lower strap portion so as to apply said one or more of a tensile / compressive, shear, or rotational torque force on the user’s knee during use, wherein the biasing force is dependent on a relative position of the first portion with respect to the second portion; and an actuator operable to move the first portion relative to the second portion to change the biasing force; a sensor arranged to detect a dynamic loading parameter of the user’s knee; and a controller configured to control the actuator in dependence on the detected dynamic loading parameter.

[0027] This has the advantage of providing a knee brace that is able to adjust, in realtime, to changes in how the knee is being used, such as differing forces going through the knee and at which point in the user’s gait cycle, as well as possible changes in position of the brace on the knee (i.e. slippage) so as to apply suitably-modified unloading forces in the form of tensile / compressive, shear, or rotational torque forces. These forces help to alleviate the pressure on the damaged area of the user’s knee joint.

[0028] The pushing forces generated by the knee brace can thus automatically adjust based on the user's walking pattern or activities. This dynamic adaptation, facilitated by the input from the sensor(s), such as an orientation and movement sensor and a force sensor, ensures efficient force unloading and comfort throughout various movements and tasks and accounts for slippage, which is a leading problem with known devices.

[0029] The biasing assembly may comprise a magnetic biasing assembly and the biasing force generator may comprise a first magnet disposed in the first portion and a second magnet, in polar opposition to the first magnet, disposed in the second portion. Each of the first and second magnets may comprise a stack of sub-magnets.

[0030] In accordance with a second aspect of the invention, there is provided an adaptive knee brace for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, the brace comprising: an upper strap portion for strapping to a user’s leg above the knee; a lower strap portion for strapping to the user’s leg below the knee; a linkage joining the upper strap portion to the lower strap portion for articulation of the upper strap portion relative to the lower strap portion; a magnetic biasing assembly comprising: a magnet arranged to impart a biasing force on the linkage to bias the upper strap portion relative to the lower strap portion so as to apply said one or more of a tensile / compressive, shear, or rotational torque force on the user’s knee during use; and an actuator operable to move the magnet to change the biasing force; a sensor arranged to detect a dynamic loading parameter of the user’s knee; and a controller configured to control the actuator in dependence on the detected dynamic loading parameter.

[0031] The use of a biasing assembly in the form of a magnetic biasing assembly has the advantage of a relatively simple construction, with readily available materials, and which provides for mechanically isolated transfer of forces through the force generator.

[0032] The magnetic biasing assembly may comprise a first magnet disposed in a first portion of a magnetic biasing force generator, and a second magnet, in polar opposition to the first magnet, disposed in a second portion of the magnetic biasing force generator. The actuator may be operable to move the first magnet relative to the second magnet. Each of the first and second magnets may comprise a stack of sub-magnets.

[0033] According to either the first or second aspects of the invention as detailed above, where including first and second magnets, the first and second portions of the biasing force generator may be telescopically coupled to one another and the first and second magnets may be slidably disposed in a hollow channel defined therewithin, and the length of the channel may be adjustable under the action of the actuator. The hollow channel may have opposed first and second ends, wherein the first magnet abuts the first end and the second magnet abuts the second end under the action of their opposed magnetic fields.

[0034] According to either the first or second aspects of the invention as detailed above, the linkage may comprise an upper member fixedly connected to the upper strap portion and terminating at an upper side of a hinge, and a lower member slidably connected to the lower strap portion and terminating at a lower side of the hinge. In certain embodiments the arrangement may be inverse, such that the upper member may be slidably connected to the upper strap portion, with the lower member fixedly connected to the lower strap portion.

[0035] The linkage according to either the first or second aspect as detailed above may be configured to be worn on a medial side of the knee. In certain embodiments, the adaptive knee brace may further comprise a second linkage configured to be worn on a lateral side of the knee, and a corresponding second biasing assembly arranged to impart a biasing force on the second linkage. Alternatively, a single linkage may be configured to be worn on a lateral side of the knee.

[0036] According to either the first or second aspects of the invention as detailed above, the dynamic loading parameter may comprise one or more of: a force passing through the linkage; a degree of articulation of the knee; movement of the upper leg strap portion relative to lower leg strap portion; movement of the user; and inertial movement; a rate of change of a force passing through the linkage; a rate of change of a degree of articulation of the knee; a rate of change of movement of the upper leg strap portion relative to lower leg strap portion; a rate of change of movement of the user; and a rate of change of inertial movement. Any of these parameters, or a combination thereof, may provide a good indication of the type of activity that the user is undertaking, such as walking, standing, climbing stairs, etc.

[0037] According to a third aspect of the invention, there is provided a method of operating an adaptive knee brace according to either the first or second aspects of the invention as detailed above, the method comprising: detecting the dynamic loading parameter of the user’s knee; and controlling the actuator in dependence on the detected dynamic loading parameter to change the force applied by the biasing assembly.

[0038] Thus, the applied force may be varied in a dynamic fashion in dependence on the detected dynamic loading parameter, which may be representative of, for example, forces through the joint, or the user’s gait.

[0039] According to a fourth aspect of the invention, there is provided a method of operating an adaptive knee brace according to either the first or second aspects of the invention as detailed above, the method comprising: detecting a force imparted on the linkage; based on the detected force, determining a slippage of the upper strap portion and / or lower strap portion on the user’s leg; and based on the determined slippage, operating the actuator to adjust the biasing force.

[0040] Thus, slippage of the brace relative to the user’s leg can be detected and mitigated, in real time, by adapting the biasing force accordingly.

[0041] The method may comprise detecting if the determined slippage exceeds a predetermined threshold and operating the actuator to adjust the biasing force in dependence on the determined slippage only when said predetermined threshold is exceeded. In other words, no adjustments of the biasing force other than responsive to the dynamic loading parameter may be made even if some minor slippage is detected; compensation for slippage only occurring beyond a given measure. In certain embodiments, the method may further comprise detecting if the determined slippage exceeds a predetermined slippage maximum and communicating information to the user responsive thereto. Thus, should a high level of slippage be detected then an alert could be generated to warn the user, which may be useful to prompt re-positioning of the brace to prevent possible injury or damage. Determining a slippage may comprise detecting sudden changes in the force imparted on the linkage.

[0042] According to a fifth aspect of the invention, there is provided a method of operating an adaptive knee brace according to either the first or second aspects of the invention as detailed above, the method comprising: detecting a movement parameter of the user and / or the user’s knee; based on the movement parameter, determining information indicative of a user’s gait or gait cycle; and based on the determined information indicative of the user’s gait or gait cycle, operating the actuator to adjust the biasing force imparted between the upper strap portion and the lower strap portion.

[0043] According to a sixth aspect of the invention, there is provided a method of operating an adaptive knee brace according to either the first or second aspects of the invention as detailed above, the method comprising: detecting a movement parameter of the user and / or the user’s knee; based on the movement parameter, determining information indicative of a user’s activity; based on the determined information indicative of the user’s activity, selecting a mode of operation of the controller; and operating the actuator to adjust the biasing force imparted between the upper strap portion and the lower strap portion according to the selected mode of operation.

[0044] Thus, a type of activity being undertaken by the user may be determined, such as running, standing, cycling, etc. and the applied biasing force(s) may be adjusted accordingly for optimum user comfort.

[0045] According to either the fifth or the sixth aspects as detailed above, the detected movement parameter may comprise one or more of: a force passing through the linkage; a degree of articulation of the knee; a rate of change of a force passing through the linkage; and a rate of change of a degree of articulation of the knee. When operation of the actuator is dependent at least partially on the determined information indicative of the user’s gait or gait cycle, the operation of the actuator to adjust the biasing force in dependence on the determined information indicative of the user’s gait or gait cycle may be harmonized to the gait cycle. In particular, the method may further comprise: determining the stage of the user’s gait cycle in dependence on the detected movement parameter; and operating the actuator so as to: apply a maximum biasing force of approximately 80-100% during 20% to 25% of the gait cycle; and apply approximately 60% of said maximum biasing force during a push-off phase, from approximately 65% to 85% of the cycle.

[0046] According to a seventh aspect of the invention, there is provided a method of operating an adaptive knee brace according to either the first or second aspects of the invention as detailed above, the method comprising: manually selecting a mode of operation of the controller; and operating the actuator to adjust the biasing force imparted between the upper strap portion and the lower strap portion according to the selected mode of operation.

[0047] Much as with the sixth aspect as detailed above, the applied biasing forces may be varied according to a selected mode of operation, but in this instance that mode is selected manually rather than purely relying on mode detection based on the detected movement parameter (for example via input from the one or more sensors). Manual selection of the mode of operation may, for example, be effected by a manual switch or by a user selection in a user interface, such as a touch screen input on an app on a mobile communication device that is in communication with the controller, for example via Bluetooth (RTM) or other communications protocol.

[0048] According to a method as defined in any of the third to seventh aspects as detailed above, the method may further comprise: inputting the user’s body weight; inputting a desired knee unloading percentage; and calculating a desired knee unloading force based on user's body weight and the input unloading percentage; wherein controlling the actuator is further in dependence on the desired knee unloading force.

[0049] Inputting the user’s weight and / or desired knee unloading percentage may be effected by the user or by a medical professional, and may be done by a selection in a user interface as above.

[0050] According to a method as defined in any of the third to seventh aspects as detailed above, the method may further comprise regulating operation of the actuator using PID control.

[0051] According to a method as defined in any of the third to seventh aspects as detailed above, the method may further comprise carrying out artificial intelligence analysis of the detected dynamic loading parameter in order to better control operation of the actuator.

[0052] Thus, a machine-learning algorithm can continuously analyse sensor inputs and user feedback. This algorithm enables the brace to learn and adapt to the user's specific requirements over time. By leveraging artificial intelligence, the knee brace offers a personalized and optimized experience that aligns with the user's unique condition and preferences. Moreover, the system can take input from multiple participants so that the machine-learning algorithm that is trained on a broader data set.

[0053] According to an eighth aspect of the invention, there is provided an adaptive knee brace for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, the brace comprising: an upper strap portion for strapping to a user’s leg above the knee; a lower strap portion for strapping to the user’s leg below the knee; a linkage joining the upper strap portion to the lower strap portion for articulation of the upper strap portion relative to the lower strap portion; a magnetic biasing assembly comprising: a biasing force generator comprising an electromagnetic member configured to impart a biasing force on the linkage to bias the upper strap portion relative to the lower strap portion so as to apply said one or more of a tensile / compressive, shear, or rotational torque force on the user’s knee during use; a sensor arranged to detect a dynamic loading parameter of the user’s knee; and a controller configured to control the electromagnetic member to change the biasing force in dependence on the detected dynamic loading parameter.

[0054] In contrast to the mechanical arrangements of the adaptive knee braces of the first or second aspects, in which the biasing force is varied by virtue of an actuator physically moving a first part of the biasing assembly relative to a second part, effectively changing the spring rate, this adaptive knee brace relies on a purely electromechanical arrangement in which the effective biasing force is adjusted, for example, by varying the current through an electromagnetic coil.

[0055] According to a ninth aspect of the invention, there is provided a method of operating an adaptive knee brace according to the eighth aspect of the invention as detailed above, the method comprising: detecting the dynamic loading parameter of the user’s knee; and controlling the electromagnetic member in dependence on the detected dynamic loading parameter to change the force applied by the biasing assembly.

[0056] This reflects the method of the third aspect, but modified for use with the brace according to the eighth aspect.

[0057] According to a tenth aspect of the invention, there is provided a method of operating an adaptive knee brace according to the eighth aspect of the invention as detailed above, the method comprising: detecting a force imparted on the linkage; based on the detected force, determining a slippage of the upper strap portion and / or lower strap portion on the user’s leg; and based on the determined slippage, operating the controller to adjust the biasing force applied by the electromagnetic member.

[0058] This reflects the method of the fourth aspect, but modified for use with the brace according to the eighth aspect.

[0059] According to an eleventh aspect of the invention, there is provided a method of operating an adaptive knee brace according to the eighth aspect of the invention as detailed above, the method comprising: detecting a movement parameter of the user and / or the user’s knee; based on the movement parameter, determining information indicative of a user’s gait or gait cycle; and based on the determined information indicative of the user’s gait or gait cycle, operating the controller to adjust the biasing force imparted between the upper strap portion and the lower strap portion by the electromagnetic member.

[0060] This reflects the method of the fifth aspect, but modified for use with the brace according to the eighth aspect.

[0061] As would be appreciated, the features discussed in relation to the apparatus of the invention apply mutatis mutandis to the discussion of the methods, which make use of the apparatus of the invention. Moreover, the features discussed in relation to the methods of the invention apply mutatis mutandis to all other aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a set of photographs showing a knee brace as worn by a user in various positions and applications; Figure 2A is a schematic front (or anterior), medial perspective view of an adaptive knee brace according to embodiments of the invention, and showing magnet and linkage assemblies transparently to depict internal components; Figure 2B is a schematic rear (or posterior), lateral perspective view of an the adaptive knee brace of Fig. 2A; Figure 3 is a perspective view from an anterior, medial direction of an adaptive knee brace according to embodiments of the invention; Figure 4 is a perspective view from a posterior, lateral direction of the adaptive knee brace of Fig. 3; Figure 5 is a rear (or posterior) plan view of the adaptive knee brace of Fig. 3; Figure 6 is a side elevation view from a medial direction of the adaptive knee brace of Fig. 3; Figure 7a is a detail of Fig 6, showing a magnet assembly in cross-section through Section A-A as shown in Fig. 7b; Figure 7b is a top plan view of the adaptive knee brace of Fig. 3 to Section A-A; Figure 8a is a detail of Fig 6, showing a magnet assembly in cross-section through Section B-B as shown in Fig. 8b; Figure 8b is a top plan view of the adaptive knee brace of Fig. 3 to Section B-B; Figure 9a is a cross-sectional frontal (anterior) view of the adaptive knee brace of Fig. 3 through Section C-C as shown in Fig. 9b, showing internals of a magnet and linear actuator assembly; Figure 9b is a top plan view of the adaptive knee brace of Fig. 3 to Section C-C; Figure 10 is a schematic perspective view from an anterior, medial direction of the adaptive knee brace of Fig. 3, akin to Fig. 3, but showing the magnet and linear actuator assembly transparently to depict the internal components; Figure 11 is a schematic, partial cross-sectional view of one embodiment of a magnet assembly; Figure 12 is a photograph from above of an alternative magnet assembly; and Figure 13a is a schematic illustration of a knee brace as worn on a user’s knee and depicting, from a frontal perspective, illustrative tensile / compressive unloading forces through the brace; Figure 13b is a corresponding schematic illustration depicting, from a medial perspective, illustrative tensile / compressive, shear and torque forces; Figure 14 is a schematic diagram of power, sensor, control and driver modules of an adaptive knee brace according to embodiments of the invention; and Figure 15 is a schematic diagram of measurement, control and unloading phases of use of an adaptive knee brace according to embodiments of the invention, including optional gait cycle input. DETAILED DESCRIPTION

[0063] An adaptive brace 100 according to embodiments of the invention is described by reference to the accompanying figures. The adaptive brace 100 comprises an upper strap portion 10 for strapping to a user’s leg above the knee (i.e. to the thigh) and a lower strap portion 16 for strapping to the user’s leg below the knee (i.e. to the shank). The upper strap portion 10 may comprise a generally curved semi-flexible U-shaped component 12 that is open towards the lateral side (as shown in the embodiment of Figures 1 and 2) or that is open towards the rear (as shown in the embodiment of Figures 3 to 10) to facilitate insertion on I removal from the thigh, and which is secured in position by one or more straps 11 passed through corresponding strap slots 13 as is known in the art. The U-shaped component 12 is typically selected to have a closely-matching profile to the user’s thigh. The lower strap portion 16 may comprise a generally curved semi-flexible U-shaped component 18 that is open towards the front to facilitate placement on / removal from the shank, and which is secured in position by one or more straps 11 passed through corresponding strap slots 13 as is known in the art. The straps 11 may be adjusted for length by way of hook and eye releasable fastening (e.g. Velcro (RTM)) or by way of suitable buckles, for example. The U-shaped component 18 is typically selected to have a closely-matching profile to the user’s shank.

[0064] A linkage 20 joins the upper strap portion 10 to the lower strap portion 16 for articulation of the upper strap portion relative to the lower strap portion. A biasing assembly 50 is arranged to impart a biasing force on the linkage 20 to bias the upper strap portion 10 relative to the lower strap portion 16 so as to apply one or more forces on the user’s knee during use. The applied forces may comprise one or more of: a tensile / compressive force, a shear force, or a rotational torque force on the user’s knee, as depicted in Figs. 13a and 13b. In this context, a tensile / compressive force F (and corresponding reaction force R) is a force urging the femur away from or towards the tibia. A shear force r may be a force urging the femur to translate anteriorly (or posteriorly), relative to the tibia. A rotational torque force T may be a force urging the femur to rotate relative to the tibia.

[0065] In one embodiment, the biasing assembly 50 comprises a biasing force generator which includes first and second portions 52,54 arranged to impart the biasing force on the linkage 20, wherein the biasing force is dependent on a relative position of the first portion 52 with respect to the second portion 54. An actuator 60 is operable to move the first portion 52 relative to the second portion 54 to change the biasing force. One exemplary actuator 60 is the Micro Electric Linear (Servo) Actuator made by MightyZAP, which has an input voltage of 12V.

[0066] In certain embodiments, and as generally illustrated, the biasing assembly 50 comprises a magnetic biasing assembly and the biasing force generator comprises a first magnet 55 disposed in the first portion 52 and a second magnet 57, in polar opposition to the first magnet, disposed in the second portion 54. The first magnet 55 may comprise a stack of sub-magnets 55a. Likewise, the second magnet 57 may comprise a stack of submagnets 57a. The actuator 60 is operable to move the first magnet 55 relative to the second magnet 57, for example by moving the first portion 52 relative to the second portion 54.

[0067] Description of an exemplary set of magnets: a. Size: 20mm diameter x 10mm thick N42 (different shapes and sizes can be used). b. Type: Neodymium Magnet - 11.5kg Pull (stronger ones could be used too). c. Number of magnets and configuration: 6 magnets divided into groups of two repelling each other (different numbers could also be used). d. Upper limits: Based on the literature, it is recommended to target approximately 10-20% of body weight (Ref. 1. Budarick, A; R., MacKeil, etal., C. D. (November 6, 2019). Design Evaluation of a Novel Multicompartment Unloader Knee Brace. ASME. J Biomech Eng. January 2020; 142(1): 014502; and Ref. 2. Polio FE and Otis JC et al. Reduction of Medial Compartment Loads with Valgus Bracing of the Osteoarthritic Knee. The American Journal of Sports Medicine. 2002;30(3):414-421). The system disclosed herein currently achieves a maximum (e.g. unloading) force of 140 N. Further testing with larger values is feasible. e. Lower limits to get an effect. Various findings exist in the literature; a notable study (Ref. 1, above) indicated that a 5% reduction in body weight can yield significant effects. A lower level of 37.5 N may be applicable.

[0068] At least one sensor is arranged to detect a so-called ‘dynamic loading parameter’ of the user’s knee. For example, a first sensor unit may comprise an inertial measurement unit (IMU) 70 for detecting dynamic movements at the IMU location. One suitable IMU 70 is the BN055, which can measure angles of up to 25 degrees. One convenient location 70a is, as shown in Figs. 1, 2 and 10, centrally on a front part of the upper strap portion component 12. It will be appreciated that the location is not limited to this position, however. A second sensor unit 72 may comprise one or more load cells for detecting the applied forces, for example as detected at the first end 53a of the hollow channel 53 as described below. The load cells may be capable of detecting loads of up to 500N, for example.

[0069] A controller 80 is configured to control the actuator 60 in dependence on the detected dynamic loading parameter, as detected by the one or more sensors 70,72. One suitable controller 80 comprises a nRF52840 processor.

[0070] The dynamic loading parameter may comprise one or more of (but not necessarily limited to): a force passing through the linkage 20; a degree of articulation of the knee; movement of the upper leg strap portion 10 relative to lower leg strap portion 16; movement of the user; and inertial movement; a rate of change of a force passing through the linkage 20; a rate of change of a degree of articulation of the knee; a rate of change of movement of the upper leg strap portion 10 relative to lower leg strap portion 16; a rate of change of movement of the user; and a rate of change of inertial movement.

[0071] In certain embodiments, the first and second portions 52,54 of the biasing force generator 50 are telescopically coupled to one another and the first and second magnets are slidably disposed in a hollow channel 53 defined therewithin. The length of the channel 53 is adjustable under the action of the actuator 60. The hollow channel 53 has opposed first and second ends 53a,53b; the first magnet 55 abuts the first end 53a and the second magnet 57 abuts the second end 53b under the action of their opposed magnetic fields. In certain embodiments, such as shown in Figs. 11 &12, a pair of channels 53,53’ are arranged in parallel. The channel or channels 53 may have a cross-section matched to the profile of the magnets 55,57 within - for example, but not exclusively, circular (Fig. 11) or square (Fig. 12).

[0072] The linkage 20 comprises an upper member 22 fixedly connected to the upper strap portion 10 and terminating at an upper side of a hinge 25, and a lower member 24 slidably connected to the lower strap portion 16 by means of a linear carriage member 26 and terminating at a lower side of the hinge 25. It will be understood that the mechanism could be inverted such that the upper member 22 is slidably connected to the upper strap portion 10, with the lower member 24 fixedly connected to the lower strap portion 16. In certain embodiments, and as best seen in Fig. 8a, the linkage 20 may comprise the upper member 22 being connected to the hinge 25 at a first pivot point 27, and the lower member 24 being connected to the hinge 25 at a second pivot point 29, with rotational movement of the upper member 22 relative to the lower member 24 being coordinated by virtue of intermeshing gear teeth 31,33 at respective opposed ends of the upper and lower members 22,24. A stopper member 21 may be included to limit hinging motion of the upper and lower members 22,24 relative to one another.

[0073] The first portion 52 of the biasing force generator 50 may be fixedly connected to the linkage 20, for example at the hinge 25. As such, the force acting on the end 53a of the channel 53 by virtue of the repelling magnets 55,57 urges the first portion 52 away from the second portion 54, ergo to urge the linkage 20 to translate within the linear carriage 26, thereby urging the upper leg strap portion 10 to move away from lower leg strap portion 16, imparting the desired biasing force on the knee.

[0074] Translation of the second portion 54 of the biasing force generator 50 relative to the first portion 52 thereof under the action of the actuator 60 moves the first end 53a of the channel relative to the second end 53b thereof, which changes the biasing force applied by the biasing force generator 50 because of a stronger or weaker interaction of the respective magnetic fields of the first and second magnets 55,57.

[0075] As depicted, the linkage 20 is configured to be worn on a medial side of the knee. By having an asymmetrical arrangement, and optionally through appropriate adjustment and positioning of the biasing force generator (e.g. to orient the direction of applied forces), it is possible to impart not only tensile / compressive forces F,R for unloading (or loading) the knee joint - e.g. urging the femur away from (or towards) the tibia, but also a shear force vfor urging the femur to translate anteriorly (or posteriorly) relative to the tibia, and / or a rotational torque force T for urging the femur to rotate relative to the tibia.

[0076] However, in certain embodiments a knee brace may include linkages 20 on both lateral and medial sides, each with associated biasing assemblies 50, to provide options for balanced application of forces or more control over application of rotational forces, for example, through differential application of biasing forces on the respective lateral and medial sides.

[0077] In some embodiments, rather than having opposed first and second magnets 55,57, there may be just a single magnet (or sub-stack thereof) arranged to act on a ferromagnetic member to provide the biasing force. In such cases, the actuator 60 is adapted to move the single magnet relative to the corresponding ferromagnetic member to vary the amount of force applied.

[0078] In some embodiments, rather than the biasing force being generated by magnetic fields and adjusted by moving the or each magnet to strengthen or weaken the effect of the magnetic field, the biasing force may be generated by mechanical means, such as a compression spring, which may be a coil spring or an air spring, by way of example. In such mechanical arrangements, the effective spring rate may be adjusted by moving the ends of the spring towards or away from one another or by changing the air pressure in a piston chamber of an air spring.

[0079] In yet other embodiments, the magnetic biasing force may be generated by means of an electromagnet. In such embodiments, there is no need for a mechanical actuator for driving relative movement of a first portion relative to a second portion; control of variation of the biasing force is effected purely electrically, for example by changing the current passing through the electromagnet.

[0080] As depicted schematically in Figs. 14 &15, the control and power aspects of the knee brace 100 may be identified as respective modules: a power module 200, which may include a battery, electrically coupled to each of: a sensor module 202, which may include the one or more sensors 70,72 as detailed above; a control module 204, which may include the controller 80; and a driver module 206, which may include the actuator 60.

[0081] The control module 204 receives signals from the sensor module 202 and sends signals to the driver module 206 in order to drive the actuator 60 accordingly to adjust the biasing assembly 50 to alter the applied biasing force, responsive to the input(s) from the sensor module 202. The signals may be transmitted wirelessly, for example using Bluetooth (RTM) protocol, or may be transmitted over wires connecting the various components of the control system, comprising the controller 80

[0082] One method of operating the adaptive knee brace 100 comprises: detecting the dynamic loading parameter of the user’s knee, for example via the one or more sensors 70,72; and controlling the actuator 60 in dependence on the detected dynamic loading parameter to change the force applied by the biasing assembly 50.

[0083] Since the detected dynamic loading parameter, may be representative of, for example, forces through the joint, or the user’s gait, the applied force may be varied in a dynamic fashion to best suit the current use of the knee.

[0084] A method of operating the adaptive knee brace 100, which may be used in conjunction with the adjustments responsive to the dynamic loading parameter or independently thereof, comprises: detecting a force imparted on the linkage 20, for example via the one or more sensors 70,72; based on the detected force, determining a slippage of the upper strap portion 10 and / or lower strap portion 16 on the user’s leg; and based on the determined slippage, operating the actuator 60 to adjust the biasing force.

[0085] Thus, slippage of the brace 100 relative to the user’s leg can be detected and mitigated, in real time, by adapting the biasing force accordingly.

[0086] In certain embodiments, such mitigation by adjustment of the biasing force responsive to a detected slippage may only be implemented if the amount of slippage is significant enough - i.e. if the determined slippage exceeds a predetermined threshold. In certain embodiments, the method may further comprise detecting if the determined slippage exceeds a predetermined slippage maximum and communicating information to the user responsive thereto. Thus, should a high level of slippage be detected then an alert could be generated to warn the user, which may be useful to prompt re-positioning of the brace 100 to prevent possible injury or damage. Determining a slippage may comprise detecting sudden changes in the force imparted on the linkage 20.

[0087] Another method of operating the adaptive knee brace 100 comprises: detecting a movement parameter of the user and / or the user’s knee, for example via the one or more sensors 70,72; based on the movement parameter, determining information indicative of a user’s gait or gait cycle; and based on the determined information indicative of the user’s gait or gait cycle, operating the actuator 60 to adjust the biasing force imparted between the upper strap portion 10 and the lower strap portion 16.

[0088] Thus, the adjustments of the applied forces may be made dynamically and in phase with a user’s gait.

[0089] By way of example, the method may include: determining the stage of the user’s gait cycle in dependence on the detected movement parameter; and operating the actuator 60 so as to: apply a maximum biasing force of approximately 80-100% during 20% to 25% of the gait cycle; and apply approximately 60% of said maximum biasing force during a push-off phase, from approximately 65% to 85% of the cycle.

[0090] Another method of operating the adaptive knee brace 100 comprises: detecting a movement parameter of the user and / or the user’s knee, for example via the one or more sensors 70,72; based on the movement parameter, determining information indicative of a user’s activity; based on the determined information indicative of the user’s activity, selecting a mode of operation of the controller 80; and operating the actuator 60 to adjust the biasing force imparted between the upper strap portion 10 and the lower strap portion 16 according to the selected mode of operation.

[0091] Thus, a type of activity being undertaken by the user may be determined, such as running, standing, climbing stairs, cycling, etc. and the applied biasing force(s) may be adjusted accordingly for optimum user comfort.

[0092] The detected movement parameter may comprise one or more of: a force passing through the linkage 20; a degree of articulation of the knee; a rate of change of a force passing through the linkage 20; and a rate of change of a degree of articulation of the knee.

[0093] Rather than determination of a user’s activity being achieved through sensor inputs, a user may directly indicate to the system what kind of activity they are undertaking (or plan to do). Thus, yet another method of operating the adaptive knee brace 100 comprises: manually selecting a mode of operation of the controller 80; and operating the actuator 60 to adjust the biasing force imparted between the upper strap portion 10 and the lower strap portion 16 according to the selected mode of operation.

[0094] Manual selection of the mode of operation may, for example, be effected by a manual switch or by a user selection in a user interface, such as a touch screen input on an app on a mobile communication device that is in communication with the controller, for example via Bluetooth (RTM) or other communications protocol.

[0095] Any of the above methods may be supplemented by reference to the user’s weight, for more accurate determination of the desired applied forces. Thus, the method may further comprise: inputting the user’s body weight; inputting a desired knee unloading percentage; and calculating a desired knee unloading force based on user's body weight and the input unloading percentage. Controlling the actuator 60 is further in dependence on the desired knee unloading force.

[0096] Inputting the user’s weight and / or desired knee unloading percentage may be effected by the user or by a medical professional, and may be done by a selection in a user interface as above.

[0097] For optimum application of applied forces, particularly where varying dynamically, operation of the actuator 60 may be regulated using PID control. As such, the controller 80 may include a PID control module.

[0098] Any of the above methods may be supplemented by machine learning and / or artificial intelligence (Al) inputs, for example carrying out analysis of the or each detected dynamic loading parameter in order to better control operation of the actuator 60. A machine-learning or Al algorithm can continuously analyse sensor inputs and user feedback. This algorithm enables the brace 100 to learn and adapt to the user's specific requirements over time. By leveraging artificial intelligence, the knee brace offers a personalized and optimized experience that aligns with the user's unique condition and preferences. Moreover, the system can take input from multiple participants so that the machine-learning algorithm can be trained on a broader data set, for example to incorporate population-wide metrics and behaviours in making the determinations.

[0099] It will be appreciated that many of the features described above, particularly of the preferred embodiments, are inventive in their own right and not just as part of an embodiment of the present invention. Independent protection may be sought for these features in addition to or alternative to any invention presently claimed.

[00100] Exemplary modes of operation

[00101] The control system of the adaptive knee brace initiates upon pressing an ON button. Users input their body weight (BW) and a desired knee unloading percentage, between 10-20%, which is then individually calculated. Subsequently, the system reads the angle and force values from sensors 70,72 located on the thigh and the top part of the lower hinge arm 24, respectively. Using these inputs, the controller 80 compares the measured angles with predefined values corresponding to the gait cycle, determining the appropriate moments for intervention.

[00102] At specific stages of the gait cycle, particularly during the stance phase when the foot is in contact with the ground, the linear actuator 60 is activated. Between 20% to 25% of the gait cycle, the system applies the maximum unloading force (ranging from 80% to 100%). During the push-off phase, from approximately 65% to 85% of the cycle, the knee is unloaded with 60% of the maximum force.

[00103] The activation of the actuator 60 starts when a negative slope in the angle is detected, applying a maximum linear force. Within the angle range of 15° to 5°, and with a negative slope, the force decreases to approximately 60% of the actuator's maximum force. Subsequently, when the angle ranges from -5° to -10°, the actuator 60 applies its maximum force at 80%. It is important to note that the values of the angles vary according to the individual, and these values were being tested for trials and standard gait cycle analysis.

[00104] The extent of the linear actuator's stroke, which determines the movement of the magnets 57, is regulated by a PID (Proportional-lntegral-Derivative) controller, ensuring precise and responsive adjustments.

[00105] Following the completion of each gait cycle, the system re-evaluates and adjusts, guided by the controller 80, to ensure optimal support and comfort throughout the user's movements. Additionally, the control system may include an artificial intelligence (Al) component, enabling it to learn and adapt from the data captured during use, ensuring continuous optimization and personalized support over time

[00106] High level algorithm: 1. Initialization: Press ON button to activate the system. Input user's body weight (BW) and desired knee unloading percentage (between 10-20%). 2. Individual Calculation: Calculate the desired knee unloading force based on user's BW and input percentage. 3. Sensor Reading: Read angle and force values from thigh and lower hinge arm sensors. 4. Angle Comparison: Compare measured angles with predefined values corresponding to the gait cycle to determine intervention moments. 5. Linear Actuator Activation: • Activate the linear actuator 60 at specific stages of the gait cycle, particularly during the stance phase. • Apply maximum unloading force (80-100%) between 20% to 25% of the gait cycle. • Apply 60% of maximum force during the push-off phase, from approximately 65% to 85% of the cycle. 6. Angle Slope Detection: Start actuator activation when a negative slope in the angle is detected. 7. Force Adjustment: • Decrease force to approximately 60% of maximum within the angle range of 15° to 5° with a negative slope. • Apply maximum force at 80% within the angle range of -5° to -10°. 8. PID Control: Regulate the extent of linear actuator's stroke using PID controller for precise and responsive adjustments of the force. 9. Re-evaluation and Adjustment: After each gait cycle, re-evaluate and adjust the system to ensure optimal support and comfort. Utilize artificial intelligence (Al) components to learn and adapt from captured data for continuous optimization and personalized support.

[00107] In summary, there is disclosed an adaptive knee brace 100 for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, the brace comprising: upper and lower strap portions 10,16 for strapping to a user’s leg above and below the knee; and a linkage 20 joining the upper and lower strap portions for articulation of the upper strap portion relative to the lower strap portion. The knee brace further includes a biasing assembly 50, which may comprise a biasing force generator comprising first and second portions 52,54 arranged to impart a biasing force on the linkage 20 to bias the upper strap portion 10 relative to the lower strap portion 16 so as to apply said one or more forces on the user’s knee during use, typically by virtue of opposed magnets 55,57 in the first and second portions 52,54. The biasing force is dependent on a relative position of the first portion 52 with respect to the second portion 54 and the brace includes an actuator 60 operable to move the first portion relative to the second portion to thereby change the biasing force. At least one sensor 70,72 is arranged to detect a dynamic loading parameter of the user’s knee, and a controller 80 is configured to control the actuator in dependence on the detected dynamic loading parameter.

[00108] The unloading of the brace 100 is efficient, and the user will experience immediate pain relief. The automatic unloading force according to the gait cycle allows the user more independence when they use the brace. With no additional tools required for adjustment, the brace 100 empowers patients to perform various tasks autonomously. By using this brace regularly, they will postpone the need for surgery for over a decade.

[00109] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[00110] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[00111] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. An adaptive knee brace for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, the brace comprising:an upper strap portion for strapping to a user’s leg above the knee;a lower strap portion for strapping to the user’s leg below the knee;a linkage joining the upper strap portion to the lower strap portion for articulation of the upper strap portion relative to the lower strap portion;a biasing assembly comprising:a biasing force generator comprising first and second portions arranged to impart a biasing force on the linkage to bias the upper strap portion relative to the lower strap portion so as to apply said one or more of a tensile / compressive, shear, or rotational torque force on the user’s knee during use, wherein the biasing force is dependent on a relative position of the first portion with respect to the second portion; andan actuator operable to move the first portion relative to the second portion to change the biasing force;a sensor arranged to detect a dynamic loading parameter of the user’s knee; anda controller configured to control the actuator in dependence on the detected dynamic loading parameter.

2. The adaptive knee brace according to claim 1, wherein the biasing assembly comprises a magnetic biasing assembly and the biasing force generator comprises a first magnet disposed in the first portion and a second magnet, in polar opposition to the first magnet, disposed in the second portion.

3. An adaptive knee brace for applying one or more of a tensile / compressive, shear, or rotational torque force to the knee, the brace comprising:an upper strap portion for strapping to a user’s leg above the knee;a lower strap portion for strapping to the user’s leg below the knee;a linkage joining the upper strap portion to the lower strap portion for articulation of the upper strap portion relative to the lower strap portion;a magnetic biasing assembly comprising:a magnet arranged to impart a biasing force on the linkage to bias the upper strap portion relative to the lower strap portion so as to apply said one or more of atensile / compressive, shear, or rotational torque force on the user’s knee during use; andan actuator operable to move the magnet to change the biasing force;a sensor arranged to detect a dynamic loading parameter of the user’s knee; anda controller configured to control the actuator in dependence on the detected dynamic loading parameter.

4. The adaptive knee brace according to claim 3, wherein the magnetic biasing assembly comprises a first magnet disposed in a first portion of a magnetic biasing force generator, and a second magnet, in polar opposition to the first magnet, disposed in a second portion of the magnetic biasing force generator, and wherein the actuator is operable to move the first magnet relative to the second magnet.

5. The adaptive knee brace according to claim 2 or claim 4, wherein the first and second portions of the biasing force generator are telescopically coupled to one another and the first and second magnets are slidably disposed in a hollow channel defined therewithin, and wherein the length of the channel is adjustable under the action of the actuator.

6. The adaptive knee brace according to claim 5, wherein the hollow channel has opposed first and second ends, wherein the first magnet abuts the first end and the second magnet abuts the second end under the action of their opposed magnetic fields.

7. The adaptive knee brace according to any preceding claim, wherein the linkage comprises an upper member fixedly connected to the upper strap portion and terminating at an upper side of a hinge, and a lower member slidably connected to the lower strap portion and terminating at a lower side of the hinge.

8. The adaptive knee brace according to any preceding claim, wherein the linkage is configured to be worn on a medial side of the knee.

9. The adaptive knee brace according to claim 8, further comprising a second linkage configured to be worn on a lateral side of the knee, and a corresponding second biasing assembly arranged to impart a biasing force on the second linkage.

10. The adaptive knee brace according to any preceding claim, wherein the dynamic loading parameter comprises one or more of: a force passing through the linkage; a degree of articulation of the knee; movement of the upper leg strap portion relative to lower leg strap portion; movement of the user; and inertial movement; a rate of change of a force passing through the linkage; a rate of change of a degree of articulation of the knee; a rate of change of movement of the upper leg strap portion relative to lower leg strap portion; a rate of change of movement of the user; and a rate of change of inertial movement.

11. A method of operating the adaptive knee brace of any of claims 1 to 10, the method comprising:detecting the dynamic loading parameter of the user’s knee; andcontrolling the actuator in dependence on the detected dynamic loading parameter to change the force applied by the biasing assembly.

12. A method of operating the adaptive knee brace of any of claims 1 to 10, the method comprising:detecting a force imparted on the linkage;based on the detected force, determining a slippage of the upper strap portion and / or lower strap portion on the user’s leg; andbased on the determined slippage, operating the actuator to adjust the biasing force.

13. The method of claim 12, comprising detecting if the determined slippage exceeds a predetermined threshold and operating the actuator to adjust the biasing force in dependence on the determined slippage only when said predetermined threshold is exceeded.

14. The method of claim 13, further comprising detecting if the determined slippage exceeds a predetermined slippage maximum and communicating information to the user responsive thereto.

15. The method of any of claims 12 to 14, wherein determining a slippage comprises detecting sudden changes in the force imparted on the linkage.

16. A method of operating the adaptive knee brace of any of claims 1 to 10, the method comprising:detecting a movement parameter of the user and / or the user’s knee;based on the movement parameter, determining information indicative of a user’s gait or gait cycle; andbased on the determined information indicative of the user’s gait or gait cycle, operating the actuator to adjust the biasing force imparted between the upper strap portion and the lower strap portion.

17. A method of operating the adaptive knee brace of any of claims 1 to 10, the method comprising:detecting a movement parameter of the user and / or the user’s knee;based on the movement parameter, determining information indicative of a user’s activity;based on the determined information indicative of the user’s activity, selecting a mode of operation of the controller; andoperating the actuator to adjust the biasing force imparted between the upper strap portion and the lower strap portion according to the selected mode of operation.

18. The method of claim 16 or claim 17, wherein the detected movement parameter comprises one or more of: a force passing through the linkage; a degree of articulation of the knee; a rate of change of a force passing through the linkage; and a rate of change of a degree of articulation of the knee.

19. The method of claim 16 or claim 18 when dependent on claim 16, wherein the operation of the actuator to adjust the biasing force in dependence on the determined information indicative of the user’s gait or gait cycle is harmonized to the gait cycle.

20. The method of claim 19, further comprising:determining the stage of the user’s gait cycle in dependence on the detected movement parameter; andoperating the actuator so as to:apply a maximum biasing force of approximately 80-100% during 20% to 25% of the gait cycle; andapply approximately 60% of said maximum biasing force during a push-off phase, from approximately 65% to 85% of the cycle.

21. A method of operating the adaptive knee brace of any of claims 1 to 10, the method comprising:manually selecting a mode of operation of the controller; andoperating the actuator to adjust the biasing force imparted between the upper strap portion and the lower strap portion according to the selected mode of operation.

22. The method of any of claims 11 to 21, further comprising:inputting the user’s body weight;inputting a desired knee unloading percentage; andcalculating a desired knee unloading force based on user's body weight and the input unloading percentage;wherein controlling the actuator is further in dependence on the desired knee unloading force.

23. The method of any of claims 11 to 22, further comprising regulating operation of the actuator using PID control.5 24. The method of any of claims 11 to 23, further comprising carrying out artificialintelligence analysis of the detected dynamic loading parameter in order to better control operation of the actuator.

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