GB2576371A

GB2576371A - Orthosis

Info

Publication number: GB2576371A
Application number: GB1813441.1A
Authority: GB
Inventors: Ko Siu-Teing; Bennett Nicole; Francis Durkin Peter; Charlotte Brunskill Lucy; Clive Jarvis Simon; Harris Graham; Saeed Zahedi Mir
Original assignee: Blatchford Products Ltd
Current assignee: Blatchford Products Ltd
Priority date: 2018-08-17
Filing date: 2018-08-17
Publication date: 2020-02-19
Also published as: GB201813441D0

Abstract

An orthosis 100 comprises a rigid shell 101 shaped to receive and partially surround a user's foot, ankle and lower shin. The rigid shell 101 is made up of a foot portion 107, an ankle portion 109 and a lower shin portion 111. The foot portion comprises a soleplate 113 and medial 115M and lateral 115L rims which extend proximally from respective medial 117M and lateral 117L edges of the soleplate 113. The orthosis further comprises a heel spring 103 which is cantilevered to absorb loads to the heel of the orthosis 100.

Description

Orthosis

Technical Field

This invention relates to a lower limb orthosis, in particular to an ankle-foot orthosis and an orthotic insole.

Background to the Invention and Prior Art

The human ankle-foot performs a wide range of functions, including shock absorption, propulsion, adapting to uneven surfaces and transferring load from the heel of the foot to the toe during walking.

Current ankle-foot orthotic devices, also known as solid ankle-foot orthotics (AFOs), are designed to support a weak or damaged ankle by providing a rigid shell. These solid AFOs are often fixed with a slightly plantarflexed alignment for improved function and comfort. This alignment sometimes requires an additional ethylene-vinyl acetate (EVA) wedge to correctly align the AFO to the user's footwear, to create the optimal shank alignment for gait. In use, the rigid shell of the AFO carries a proportion of the loads applied to the foot and ankle during normal walking. However, the rigid shell also prevents or limits the ankle and foot from moving through a natural range of motion.

Recent advances in the design of orthotics have seen the inclusion of dynamic struts at the back of the orthosis which bend under a dorsi-flexing load and then recover as load is transferred. This is in order to help propel the user towards the next step. These designs are primarily aimed at the 3rd rocker performance of the orthosis (the part of the gait cycle starting with the heel lifting away from the ground) and have led to some improvements in propulsion. However, these designs do not address the requirements that are currently met by a natural foot and ankle movement, such as: shock absorption at heel strike; tibial progression through mid-stance; and comfort and conformance when standing on or traversing uneven ground.

US-A1-2012/0271214 and US-A1-2013/0165833 describe an exoskeletal orthosis which includes a proximal cuff comprising a hinge along an upper edge of the cuff, an ankle section/footplate and at least one posterior strut connecting the proximal cuff to the ankle section and footplate.

Elaine Owen, The importance of being earnest about shank and thigh kinematics especially when using ankle-foot orthoses, Prosthetics and Orthotics International, September 2010; 34(3):254-269 reviews the evidence for important observations of normal and pathological gait and presents an approach to rehabilitation and orthotic management which is based on the significance of shank and thigh kinematics for standing and gait.

Elaine Owen et al., Effect of walking in footwear with varying heel sole differentials on shank and foot segment kinematics, Prosthetics and Orthotics International, 8 September 2017, considers the similarity between the sagittal kinematics of the base of footwear during the gait cycle and barefoot foot kinematics.

Summary of the Invention

According to the invention there is provided a lower limb orthosis comprising a soleplate and a heel spring extending from the soleplate.

The orthosis may have a front foot portion, a heel portion and a central portion between the front foot and heel portions, and the heel spring may extend from the central portion. Alternatively the heel spring may extend from the front foot portion or from the heel portions.

The orthosis may further comprise mounting means for releasably mounting the heel spring to the soleplate, to provide convenient exchange of one heel spring for another heel spring.

The heel spring may extend from the central portion and/or as a cantilever.

The mounting means may comprises one or more threaded fastener for attaching the heel spring to the soleplate.

The soleplate may comprise a depression and the mounting means may further comprise an anchor plate which is accommodated within the depression.

The orthosis may further comprise a cover piece for covering the anchor plate and for providing a continuous upper surface to the soleplate.

The mounting means may further comprise one or more washer and/or nut.

The heel spring may comprise one or more elongate bores to allow longitudinal adjustment of the heel spring relative to the soleplate and optionally adjustment of heel height.

The central portion of the soleplate and the heel spring may be flat where they are mounted to each other.

The central portion of the soleplate and the heel spring may be curved where they are mounted to each other.

The heel spring may be at least partially longitudinally split.

The orthosis may be an ankle-foot orthosis and the soleplate may form part of a shell which further comprises a proximally extending wall for partially surrounding a foot and ankle, and optionally a shin, of a user.

The orthosis may further comprise a proximal cuff mounted to the shell by means of one or more posterior struts. Where there are two struts, the struts may have different stiffness to provide control of torsional resistance. Where there are more than two struts, two or more of the struts may have different stiffness to provide control of torsional resistance.

The orthosis may further comprise a heel cap removably mountable on the heel spring.

The heel cap may be mountable on the heel spring in one of two position so as to adjust the height of the heel.

The heel cap may have a lower portion which is mountable on the heel spring and an upper portion which is disposable under the heel portion of the soleplate.

The orthosis may further comprise a buffer disposed between the heel spring and the soleplate.

The buffer may be resiliently deformable and/or removably disposed between the heel spring and the soleplate, so allow the user to change the buffer for different activities, e.g., when transitioning between running and walking.

Description of the Drawings

Some embodiments of apparatus and/or methods in accordance with embodiments of the present invention are now described, by way of example only, and with reference to the accompanying drawings, in which:

Figure 1A is a cross sectional view of an orthosis according to a first embodiment of the present invention;

Figure IB is an enlarged cross sectional view of part of the orthosis of Figure 1A;

Figure IC is an anterior view of the orthosis of Figure 1A;

Figure ID is a lateral view of the orthosis of Figure 1A;

Figure IE is a view of an underside of the orthosis of Figure 1A;

Figure IF is a view of an underside of an orthosis according to a second embodiment of the invention which differs slightly form the orthosis of Figure 1A;

Figure 2A is a cross sectional view of an orthosis according to a third embodiment of the present invention;

Figure 2B is an enlarged cross sectional view of part of the orthosis of Figure 2A;

Figure 2C is an anterior view of the orthosis of Figure 2A;

Figure 2D is a lateral view of the orthosis of Figure 2A;

Figure 2E is a view of an underside of the orthosis of Figure 2A;

Figure 3A is a cross sectional view of an orthosis according to a fourth embodiment of the present invention;

Figure 3B is an anterior view of the orthosis of Figure 3A;

Figure 3C is a lateral view of the orthosis of Figure 3A;

Figure 3D is a view of an underside of the orthosis of Figure 3A;

Figure 4A is a cross sectional view of an orthotic insole according to a fifth embodiment of the present invention;

Figure 4B is an anterior view of the orthotic insole of Figure 4A;

Figure 4C is a lateral view of the orthotic insole of Figure 4A;

Figure 4D is a view of an underside of the orthotic insole of Figure 4A;

Figure 5A is a cross sectional view of an orthosis according to a sixth embodiment of the present invention in a first operating position;

Figure 5B is an enlarged cross sectional view of part of the orthosis of Figure 5A;

Figure 5C is a lateral view of the orthosis of Figure 5A;

Figure 5D is a view of an underside of the orthosis of Figure 5A;

Figure 5E is a cross sectional view of an orthosis according to the sixth embodiment of the present invention in a second operating position;

Figure 5F is an enlarged cross sectional view of part of the orthosis of Figure 5E;

Figure 5G is a lateral view of the orthosis of Figure 5E;

Figure 5H is a view of an underside of the orthosis of Figure 5E;

Figure 6A is a cross sectional view of an orthosis according to a seventh embodiment of the present invention;

Figure 6B is an enlarged cross sectional view of part of the orthosis of Figure 6A;

Figure 60 is a lateral view of the orthosis of Figure 6A;

Figure 6D is a view of an underside of the orthosis of Figure 6A;

Figures 7A is a first perspective view of a first heel cap for use with an orthosis of the present invention;

Figure 7B is a second perspective view of the heel cap of Figure 7A;

Figure 7C is a lateral view of the heel cap of Figure 7A;

Figure 7D is an anterior view of the heel cap of Figure 7A;

Figure 7E is a lateral view of the orthosis shown in Figure 6C on which is mounted the heel cap of Figure 7A;

Figures 8A is a first perspective view of a second heel cap for use with an orthosis of the present invention;

Figure 8B is a second perspective view of the heel cap of Figure 8A;

Figure 8C is a lateral view of the heel cap of Figure 8A;

Figure 8D is an anterior view of the heel cap of Figure 8A;

Figure 8E is a lateral view of the orthosis shown in Figure 6C on which is mounted the heel cap of Figure 8A;

Figure 8F is a lateral view of an orthosis according to any embodiment of the present invention comprising an alternative embodiment of the heel cap of Figure 8A;

Figure 9A is a perspective view of a third heel cap for use with an orthosis of the present invention;

Figure 9B is an anterior view of the heel cap of Figure 9A;

Figure 9C is a lateral view of the heel cap of Figure 9A;

Figure 9D is a lateral view of the orthosis shown in Figure 6C on which is mounted the heel cap of Figure 9A in a first position; and

Figure 9E is a lateral view of the orthosis shown in Figure 6C on which is mounted the heel cap of Figure 9A in a second position.

Description of Embodiments

Figures 1A-1E are views of an ankle-foot orthosis (AFO) 100 according to a first embodiment of the present invention, where Figure 1A is a section taken along line A-A of Figure IC. The AFO 100 comprises a rigid shell 101 and a heel spring 103 which is releasably mounted to the shell 101 by means of a mounting arrangement 105.

The rigid shell 101 is shaped to receive and partially surround a user's foot, ankle and lower shin. The rigid shell 101 is made from a light, high strength material. In this embodiment the rigid shell 101 is integrally formed from a composite material such as carbon fibre. In other embodiments plastics can be used, such as engineering thermoplastics. The rigid shell 101 is made up of a foot portion 107, an ankle portion 109 and a lower shin portion 111.

The foot portion 107 is shaped to partially surround the user's foot and comprises a soleplate 113 and medial 115M and lateral 115L rims which extend proximally from respective medial 117M and lateral 117L edges of the soleplate 113. The soleplate 113 is shaped to generally support the sole of a foot. The soleplate 113 comprises a heel portion 113H, a central portion 113C and a front foot portion 113F. An upper surface 119 of the central portion 113C includes a depression 121 to define a cavity 123 for accommodating an anchor plate 125 and a cover piece 137, as is described below. A lower surface 127 of the depression 119 is flat to act as a mounting platform for the heel spring 103. The soleplate 113 further comprises two bores 129 passing through the depression 121. The two bores 129 are located medially and laterally of each other at the same anterior-posterior position along the length of the soleplate 113. The bores 129 are adapted to receive screws 131, as is described below.

The ankle portion 109 of the rigid shell 101 comprises a continuous curved wall 133 having medial 133M, posterior 133P and lateral 133L portions which extend proximally from the soleplate 113 to surround the heel and ankle of the user on three sides. The lower shin portion 111 of the rigid shell 101 comprises a continuous curved wall 135 having medial 135M, posterior 135P and lateral 135L portions which extend proximally from the ankle portion 109 to surround rear, medial and lateral sides of a user's lower shin.

The anchor plate 125 is shaped to fit snugly within the cavity 123 defined by the depression 121 in the central portion 113C of the soleplate 113. The anchor plate 125 only partially fills the depth of the cavity 123 since the cover piece 137 is provided to be placed over the anchor plate 125. The function of the cover piece 137 is to cover the anchor plate 125 and heads 131H of the screws 131, and to provide continuity between an upper surface 141 of the heel portion 113H of the soleplate 113 and an upper surface 143 of the front foot portion 113F of the soleplate 113. The anchor plate 125 has two countersunk bores 139 which are each aligned with the corresponding bore 129 in the depression 121 and shaped to receive the head 131H of the corresponding screw 131. Alternatively, the bores 139 in the anchor plate 125 may be counter bored to receive a correspondingly shaped head of any other type of screw or bolt. The bores 139 are positioned coaxially with respect to the bores 129 in the depression 121, such that the screw 131 is inserted from above the anchor plate 125 when the anchor plate 125 is disposed within the cavity 123 in the upper surface 119 of the soleplate 113. The anchor plate 125 is made from a high strength metal or alloy such as aluminium, titanium or stainless steel. Alternatively the anchor plate 125 can be made from a composite material such as carbon fibre, injection moulded fibre reinforced plastic or other plastic.

The heel spring 103 of the AFO 100 is cantilevered to absorb loads to the heel of the AFO 100. In the present embodiment, the heel spring 103 is a leaf spring. Particularly, in this embodiment, the heel spring 103 has an elongated shape and continuous upper 145U and lower 145L major surfaces. The heel spring 103 has a substantially flat portion 147 at its anterior end which in use is arranged to be mounted against the lower surface 127 of the depression 121. The heel spring 103 has a posterior portion 149, which is arranged to come into contact with the insole of a shoe on heel strike and a central portion 151 between the anterior 147 and posterior 149 portions. The heel spring 103 is made from a light, flexible high strength composite material such as carbon fibre and which may be the same material from which the rigid shell 101 is made. The heel spring 103 further comprises two bores 153. The bores 153 are positioned in the flat portion 147 of the heel spring 103, which performs as a coupling portion, such that they are coaxial with the bores 129 in the soleplate 113 and the bores 139 in the anchor plate 125. Each bore 153 is counter bored such that it receives a rivet nut 159 or a threaded insert from the distal side of the heel spring 103. Alternatively, the bores 153 may be shaped to receive any other type of nut or attachment mechanism.

The heel spring 103 is detachably coupled to the lower surface 127 of the depression 121 of the soleplate 113. Particularly, a proximal face 155 of the coupling portion (i.e. flat portion 147) of the heel spring 103 is coupled to the lower, distal surface 127 of the depression 121, and the central 151 and posterior 149 portions of the heel spring 103 extend towards the posterior of the AFO 100 so as to form a proximal-distal gap 157 between the heel spring 103 and the heel portion 113H of the soleplate 113. The heel spring 103 is detachably coupled to the soleplate 113 by means of the anchor plate 125, the screws 131 and nuts 159. The screws 131 are inserted from a proximal side of the soleplate 113, i.e., an inside of the rigid shell 101 through the anchor plate 125, soleplate 113 and heel spring 103 via their respective bores 129, 139 and 153. The nuts 159 are disposed on a distal side 161 of heel spring 103 and are arranged to receive the screws 131 such that the flat portion 147 of the heel spring 103 is securely coupled to the lower, distal surface 127 of the depression 121. The screws 131 and nuts 159 are made from stainless steel and can be made from other suitable materials. Screws 131 of different length, diameter, and head type are within the scope of the invention. As such, the bores 129, 139 and 153 and nuts 159 may be configured accordingly to accommodate other type of screw. Similarly, it will be appreciated that different types of nuts may be used.

The cover piece 137 is disposed within the cavity 123 of the depression 121 over the anchor plate 125. The cover piece 137 is shaped to fill a remaining depth of the cavity 123 above the anchor plate 125 to define a continuous, gently curving surface 119 on the proximal side of the soleplate 113 over the depression 121. Hence, in use, the cover piece 137 protects a bottom of a user's foot from the anchor plate 125, the screws 131 and edges of the cavity 123 of the depression 121. The cover piece 137 is made from sponge, foam or any other suitably soft, resilient or compliant material.

A user wearing the AFO 100 benefits from its shock absorption properties. At heel strike of the gait cycle, the posterior 149 and central 151 portions of the heel spring 103 deflect from their at rest positions towards the heel portion 113H of the soleplate 113. The heel spring 103 may or may not deflect sufficiently to touch the heel portion 113H of the soleplate 113, depending on the specific design and properties of the heel spring 103, the characteristics of the user and the specifics of the gait (e.g., how fast the user is walking). Nevertheless, throughout deflection, the coupling means (i.e., the anchor plate 125, the screws 131 and the nuts 159) maintains the coupling between the coupling portion 147 of the heel spring 103 and the distal surface 127 of the depression 121. Hence, in a deflected position, the heel spring 103 absorbs the shock load produced by the heel strike and stores the associated energy.

In use, the AFO 100 also aids with tibial progression through the mid-stance of the user's gait cycle. Particularly, when the user begins to move their foot through the mid-stance of the gait cycle, the energy stored in the resiliently deformable heel spring 103 following heel strike is returned as the heel spring 103 returns to its at rest position. This provides the user with a more controlled and fluid movement into the toe-off part of the gait cycle. This also helps preserve momentum during walking and leads to a more energy efficient gait cycle, since the energy stored by the heel spring 103 at heel strike is returned to help propel the user through the mid-stance.

The AFO 100 also provides for a more comfortable stance for a user. This is because, when a user is standing, the user is effectively supported on a balanced spring system provided by the heel spring 103.

The detachable nature of the coupling means for coupling the heel spring 103 to the soleplate 113 described above provides a user or orthotic specialist with the ability to remove the heel spring 103 and install alternative heel springs 103. For example, if it is determined that the patient requires a new heel spring 103 with different stiffness properties or a different shape, a specialist may replace the heel spring 103 that is presently part of the AFO 100. This can be achieved by: removing the cover piece 137; loosening the screws 131 and/or nuts 159 to free the heel spring 103 from the anchor plate 105 and soleplate 113; coupling the new heel spring 103 to the soleplate 113 and anchor plate 125 via the screws 131 and nuts 159; and replacing the cover piece 137. In this respect, it will be appreciated that a heel spring 103 of any size, shape, material and stiffness may be coupled to the soleplate 113, as long as it has a coupling portion that is compliant with the soleplate 113 as described above. Additionally, as a result of the variable types of heel spring 103 that are within the scope of the invention, the gap 157 between the heel spring 103 and the heel portion 113H of the soleplate 113 may be of any height, shape or angle depending on the heel spring 103 that is used. The ability to couple a range of heel springs 103 to the soleplate 113 presents the advantage of customising the heel spring 103 and AFO 100 based on the needs of individual users.

An alternative embodiment of the AFO 100' is shown in Figure IF. This embodiment of the invention differs slightly form the orthosis 100 of Figure 1A, in that the heel spring 103' has a longitudinal split 104 which extends from a posterior 103P of the heel spring 103'. In addition to the advantages and uses of the heel spring 103 described above, the heel spring 103' with the longitudinal split 104 improves the compliance of the AFO 100' to uneven surfaces. Hence, it is anticipated that the longitudinal split 104 improves walking and standing comfort of the patient, in particular when walking on certain terrains. For the avoidance of doubt, although the second embodiment of the AFO 100' is shown as a modification of the first embodiment of the AFO 100, the split 104 in the heel spring 103' can also be applied to the embodiments described below.

In another alternative embodiment, at least one of the bores 153 in the flat portion 147 of the heel spring 103 may be a slot (rather than a round bore) as is described below. In another alternative embodiment, the bores 153 may both be longitudinal slots, such that the heel spring 103 is slidably adjustable with respect to its longitudinal position along the soleplate 113. In another alternative embodiment, one of the bores 153 may be an arc shaped slot, such that the heel spring 103 is rotatably adjustable with respect to the soleplate 113. In another alternative embodiment, the bores 153 may be a combination of longitudinal and/or arc shaped slots. The ability to alter the position of the heel spring 103 with respect to the soleplate 113 allows for a user or specialist to fine-tune the position of the heel spring 103 for the individual user's gait cycle or walking pattern. Additionally, such customisation is useful in the event that the AFO 100, particularly the heel spring 103, needs adjusting to comply with a user's specific footwear.

In another alternative embodiment, the AFO 100 comprises a buffer (not shown) in the gap 157 between the heel spring 103 and the heel portion 113H of the soleplate 113. The buffer is configured to modify the stiffness characteristics of the heel spring 103. For example, the buffer may be a filler disposed in the gap 157 between the heel spring 103 and the soleplate 113. Such a filler may be made from rubber or a polymeric material, or any other resilient material or compound. Alternatively, the buffer may be a removable wedge disposed in the gap 157 between the heel spring 103 and the soleplate 113. The removable wedge may be made from rubber or a polymeric material such as polyurethane, or any other resilient material or compound. Alternatively, the buffer may be a coil spring disposed in the gap 157 between the heel spring 103 and the heel portion of the soleplate 113, such that the coil spring compresses when the heel spring 103 deflects towards the heel portion 113H of the soleplate 113. Alternatively, the buffer may be a combination between any of a filler, removable wedge and a coil spring. A buffer in accordance with any of the previous alternative embodiments allows for the stiffness characteristics of the heel spring 103 to be modified without modifying or changing the heel spring 103 itself. This is advantageous as it allows for the AFO 100 to be fine-tuned to suit the needs of an individual user during fitting or home use of the AFO 100. For example, if a user wishes to increase his/her level of activity (e.g. running), an appropriate buffer can be applied to the AFO 100 to increase the effective stiffness of the heel spring 103 so that it can withstand higher shock loads. If the buffer is removable, this also gives the user the option to remove the buffer during periods of lower activity level. Hence, the AFO 100 can provide dynamic comfort based on the changing activity levels of the patient.

Figures 2A-2E show various perspective views of an AFO 200 according to a third embodiment of the present invention, where Figure 2A is a section taken along line A-A of Figure 2C. The AFO 200 is in most part similar to the AFO 100 in the first embodiment of the invention. Particularly, the soleplate 213 and mounting arrangement 205 of the AFO 200 correspond to those of the AFO 100. Additionally, the alternative embodiments and advantages described above with respect to the first embodiment ofthe invention are also envisaged with respect to the third embodiment of the invention. The differences between the AFO 200 according to the third embodiment and the AFO 100 according to the first embodiment are described below.

Instead of the AFO 100 having a single rigid shell which extends proximally from the soleplate 113 up to and around the rear of the user's shin (as in the rigid shell 101 in the first embodiment of the present invention), the AFO 200 has a shorter rigid shell 201 which does not extend proximally beyond the ankle portion. Instead, the rigid shell 201 is coupled to a proximal rigid cuff 202 via two parallel posterior struts 204. The two parallel posterior struts 204 may have asymmetric stiffness, to provide controlled torsional resistance. The proximal cuff 202 is made from the same material as the rigid shell 201 and may be made from a hard, flexible composite material such as carbon fibre. The AFO is provided with one or more straps (not shown) which pass between lateral 206 and medial 208 sides of the rigid cuff 202 and around an anterior of the user's upper shin.

In use, the AFO 200 provides a patient with additional support through the gait cycle.

Figures 3A-3D show various views of an AFO 300 in accordance with a fourth embodiment of the present invention, where Figure 3A is a section taken along line A-A of Figure 3B. The AFO 300 comprises a rigid shell 301 configured to receive a human ankle and foot. The rigid shell 301 is made from a light, high strength composite material such as carbon fibre.

Similarly to the previous embodiments, the rigid shell 301 comprises a soleplate 313 configured to support a human foot. As with the previous embodiments, the soleplate 313 is positioned at the distal end of the rigid shell 301 and is integral to the rigid shell 301. The AFO 300 similarly includes a heel spring 303, however the heel spring 303 is not mounted by means of a separable mounting arrangement as in the previous embodiments, but is integrally formed together with the rigid shell 301. Consequently, the soleplate 313 differs in that its central portion 313C has an increased thickness with respect to front 313F and heel 313H portions of the soleplate 313. Other than the manner in which the heel spring 303 is attached to the soleplate 313, it has similar properties to the heel springs 103, 203 of the first two embodiments.

In use, the AFO 300 provides similar advantages to the first, second and third embodiments of the present invention, albeit around the user's foot and ankle only. Particularly, the AFO 300 is beneficial for: absorbing shock loads to the heel; aiding tibial progression through the mid- stance of the gait cycle; and providing more comfortable standing. Additionally, the AFO 300 with the integrally formed heel spring 303 provides for a faster and simpler manufacturing process of the AFO 300, since it has less parts.

In an alternative embodiment of the AFO 300, the AFO 300 may comprise a buffer disposed between the heel spring 303 and the heel portion 313H of the soleplate 313, the details and advantages of which have been previously described. In another alternative embodiment of the AFO 300, the heel spring

303 may comprise a longitudinal split, the details and advantages of which have also been previously described.

Figures 4A-4D show an orthotic insole 400 in accordance with a fifth embodiment of the present invention. The insole 400 comprises a soleplate 413 configured to support a human foot. The soleplate 413 comprises a heel portion 413H, a central portion 413C and a front foot portion 413F, similar to the soleplate 113, 213, 313 of the previous embodiments. The insole 400 is made from a light, high strength composite material such as carbon fibre.

The insole 400 comprises a heel spring 403 configured to absorb shock loads to the heel of the insole 400. In this embodiment, the heel spring 403 is integrally coupled to a lower surface 427 of the central portion 413C of the soleplate 413 and extends towards a posterior of the insole 400, defining a gap 457 between the heel spring 403 and the heel portion 413H of the soleplate 413. The heel spring 403 has a similar overall shape and function to the heel springs 103, 203, 303 of the previous embodiments.

In use, the insole 400 provides a patient with the advantages of: absorbing shock loads to the heel; aiding tibial progression through the mid-stance of the gait cycle; and providing more comfortable standing, as previously described. Additionally, the insole 400 has the benefit of being more compliant with a patient's footwear and being easier to manufacture since it is relatively small and comprises fewer and simpler parts.

In an alternative embodiment of the insole 400, the insole 400 may comprise a buffer disposed between the heel spring 403 and the heel portion 413H of the soleplate 413, the details and advantages of which have been previously described. In another alternative embodiment of the insole 400, the heel spring 403 may comprise a longitudinal split, the details and advantages of which have also been previously described.

Figures 5A-5H show perspective views and operating positions of an AFO 500 according to a sixth embodiment of the present invention, where Figures 5A and 5E are sections taken along line A-A of Figure 5D and line E-E of Figure 5H respectively. The AFO 500 provides an alternative heel spring 503 and mounting arrangement 505 to those described in the first, second and third embodiments of the present invention. The heel spring 503 and mounting arrangement 505 of the present embodiment allows for an adjustable proximal-distal gap 557. The differences between the AFO 500 and the first, second and third embodiments are described as follows. All other aspects and advantages of the AFO 500 are otherwise regarded to be substantially the same or similar to the AFO 100 and the AFO 200 in the first, second and third embodiments and related alternative embodiments.

In the present embodiment of the AFO 500, a lower surface 527 of the depression 521 is not flat as described in previous embodiments. Instead, the lower surface 527 is curved with a uniform radius. The lower surface 527 is concavely curved with a centre of curvature at a point below the lower surface 527. A base 524 of the cavity 523 formed in the depression 521 is correspondingly convexly curved since the base 524 has a uniform thickness. As described in previous embodiments, the anchor plate 525 is shaped to snugly fit within the cavity 523 defined by the depression 521. Hence, in the present embodiment, the anchor plate 525 has a correspondingly concavely curved lower surface to snugly fit into the cavity 523.

The AFO 500 comprises bores 529 passing through the depression 521, the central axis of each bore 529 being relatively vertical through the curvature of the lower surface 527 of the depression 521. As described in previous embodiments, the bores 529 passing through the depression 521 are located medially and laterally of each other at the same anterior-posterior position along the length of the soleplate 513. Additionally, the two bores 539 in the anchor plate 525 of the present embodiment are coaxially aligned with the corresponding bores 529 in the depression 521 as previously described. In the present embodiment, the bores 529 passing through the depression 521 and the bores 539 in the anchor plate 525 are both partially and cooperatively countersunk to provide an overall countersunk region between the anchor plate 525 and the depression 521 to accommodate a head 531H of a countersunk screw 531. Hence, the bores 529 and 539 are arranged so that the screw 531 can be inserted from above the anchor plate 525 when the anchor plate 525 is disposed within the cavity, so that the head of the screw head 531H does not protrude above the anchor plate 525.

The heel spring 503 comprises a curved portion 547 at its anterior end (i.e., as opposed to a substantially flat portion as described in previous embodiments), which is arranged to be mounted against the curved lower surface 527 of the depression 521. The curved portion 547 of the heel spring 503 has substantially the same radius of curvature as the lower surface 527 of the depression 521 with a centre of curvature below the heel spring 503. The heel spring 503 comprises two elongated bores 553 positioned on the curved portion 547 of the heel spring 503. The bores 553 are elongated in the anterior-posterior direction and are located medially and laterally of each other. Each elongated bore 553 is arranged to be longitudinally in line with a respective bore 529 in the depression 521 and bore 539 in the anchor plate 525 when the heel spring 503 is mounted against the soleplate 513, thus providing a hole through the anchor plate 525, depression 521 and heel spring 503 at any anterior-posterior position along the elongated bores 553. In particular, the bores 553 are arranged so that the screw 531 can be received through the anchor plate 525, depression 521 and heel spring 503 at any anterior-posterior position along the elongated bores 553. Each bore 553 is also counter bored so that it can receive at least a portion of a rivet nut 559 or a threaded insert from the distal side of the heel spring 503 at any anterior-posterior position along the elongated bore 553.

The present embodiment of the AFO 500 also includes a shim washer 565 arranged to translate the concavely curved distal side of the curved portion 547 of the heel spring 503 to a flat surface that is perpendicular to the axis of the screw 531, to which the nuts 559 can abut against. The washer 565 is generally wedge-shaped and comprises a convexly curved upper surface 565U, a flat lower surface 565L and two bores 567. The washer 565 has a length approximately equal to the width of the heel spring 503. The curved upper surface 565U has a radius of curvature substantially similar to that of the curved lower surface of the depression 521 and the curved anterior portion 547 of the heel spring 503, with a centre of curvature below the washer 565. The convexly curved upper surface 565U is arranged to abut the concavely curved distal side of the curved portion 547. The bores 567 are located medially and laterally of each other at the same anterior-posterior position on the bracket 565 with respect to the AFO 500. Each bore 567 is arranged to coaxially align with a respective bore 529 in the depression 521 and bore 539 in the anchor plate 525 via a respective elongated bore 553 in the heel spring 503 when the upper surface 565U of the bracket 565 is placed against the curved distal side of the curved portion 547 of the heel spring 503. Each bore 567 is arranged to receive a distal end of a screw 531 via the upper side 565U of the washer 565, and a rivet nut 559 via the lower side 565L of the washer 565. The flat lower surface 565L is arranged to be substantially perpendicular to the axis of the screw 531 when the upper surface 565U of the shim washer 565 is placed against the curved distal side of the curved portion 547 of the heel spring 503 to align the bores 567 with the bores 529, 539 and 553.

The heel spring 503 is detachably coupled to the lower surface 527 of the depression 521 of the soleplate 513. A proximal face 555 of the curved portion 547 of the heel spring 503 is coupled to the curved lower surface 527 of the depression 521 to form a proximal-distal gap 557 between the posterior portion 549 of the heel spring 503 and the heel portion 513H of the soleplate 513. The heel spring 503 is detachably coupled to the soleplate 513 by means of the anchor plate 525, the shim washer 565, the screws 531 and the nuts 559. The screws 531 are inserted from the proximal side of the soleplate 513 through the anchor plate 525, the depression 521, the heel spring 503, and the shim washer 565 via their respective bores 539, 529, 553 and 567. The nuts 559 are disposed on a distal side of the washer 565 and are arranged to receive the screws 531 such that the curved portion 547 of the heel spring 503 is securely coupled to the curved lower surface 527 of the depression 521.

In the present embodiment of the invention, the height of the proximal-distal gap 557 is readily adjustable without the need to modify or change the heel spring 503 or use any alternative components. Such functionality is provided at least by virtue of the curvature of the lower surface of the depression 521 and the heel spring 503, the elongated bores 553 in the heel spring, and the shim washer 565. Figures 5A-5D show an arrangement of the AFO 500 where a maximum proximal-distal gap 557 is provided. As shown in these figures, the curved anterior portion 547 of the heel spring 503 is coupled to the soleplate

513 via the screws 531, nuts 559 and shim washer 565 at the anterior-most side of the elongated bores 553. The height of the proximal-distal gap 557 is reduced by sliding the heel spring 503 forward, by moving the coupling position to a different point on the curve of the portion 547, i.e., by coupling the screws 531, nuts 559, shim washer 565 and heel spring 503 at a different position on the elongated bores 553. For example, Figures 5E-5H show an arrangement of the AFO 500 where the proximal distal gap 557 is reduced in comparison to the arrangement in Figures 5A-5D. As shown in these figures, the heel spring 503 is coupled to the soleplate 513 via the screws 531, nuts 559 and shim washer 565 at a more posterior position along the elongated bores 553. By virtue of the curvature of the heel spring 503, the posterior portion of the heel spring 547 is raised in this position, and therefore the size of the proximal-distal gap 557 is reduced.

The height of the proximal-distal gap 557 is adjusted by partially loosening the nuts 559, after which the heel spring 503 has free longitudinal movement along the elongated bores 553 relative to the rest of the AFO 500, to allow adjustment of the relative position between the heel spring 503 and the soleplate 513. Once a position is chosen, the nuts 559 are tightened. The washer 565 guarantees a secure coupling between the heel spring 503 and the soleplate 513 for all possible positions of the heel spring 503 by virtue of its curved upper surface 565U and flat lower surface 565L.

In an alternative embodiment of the AFO 500, the position of the heel spring 503 and the size of the proximal-distal gap 557 may be slidably adjustable without the need to loosen the coupling. Furthermore, in other embodiments, the elongated bores 553 may comprise ridges or gears to allow discrete movement of the heel spring 503 to adjust the size of the proximal-distal gap 557.

Figures 6A-6D show an AFO 600 according to a seventh embodiment of the present invention, where Figure 6A is a section taken along line A-A of Figure 6D. The AFO 600 provides an alternative heel spring 603 and mounting arrangement 605 to those described in the first, second and third embodiments of the invention. The differences between the AFO 600 and the first, second and third embodiments are described as follows. All other aspects and advantages of the AFO 600 are substantially the same as or similar to those of the first, second and third embodiments and related alternative embodiments.

The mounting arrangement 605 of the AFO 600 differs from the first, second and third embodiments by the configuration of the heel spring 603, anchor plate 625 and screws 631. The AFO 600 comprises two bores 629 in the depression 621 of the soleplate 613 as described in the first, second and third embodiments. The anchor plate 625 comprises two bores 639 that are coaxially aligned with the corresponding bores 629 in the depression 621 of the soleplate 613. However, unlike the first, second and third embodiments, the bores 639 are not countersunk to receive the head 631H of a screw 631. The bores 639 are instead shaped to receive the threaded portion of the screw 631. Furthermore, the bores 639 are threaded corresponding to the threading of the screw 631.

The AFO 600 also comprises a heel spring 603 that is substantially similar to the heel springs previously described with respect to the first, second and third embodiments. The heel spring 603 comprises two countersunk bores 653 that are arranged coaxially with respect to the bores 629 and 639 when the heel spring 603 is mounted against the lower surface 627 of the depression 621. Each bore 653 is countersunk in a proximal direction, i.e., to receive the head 631H of the screw 631 from the distal side of the heel spring 603, so that the head 631H of the screw 631 is at least partially flush with the distal side 661 of the heel spring 603. Alternatively, the bores 653 may be counterbored to receive a correspondingly shaped head of any other type of screw or bolt.

In the present embodiment, the heel spring 603 is detachably coupled to the soleplate 613 by means of the anchor plate 625 and the screws 631, without the need for any nuts. The screws 631 are inserted from a distal side 661 of the heel spring 603 and through the heel spring 603, depression 621 in the soleplate 613, and the anchor plate 625 via their respective bores 653, 629 and 639. A particular advantage is that the need for nuts to couple the heel spring 603 to the soleplate 613 is eliminated, which may lead to savings in component costs and ease of coupling.

In an alternative embodiment, since the screws 631 are inserted from the distal side of the heel spring 603, the AFO 600 may be formed with an integrated anchor plate 625 without the need for a cover piece 637, again reducing the number of parts.

Figures 7A-7E show an embodiment of a removable heel cap 771 that is arranged to be placed over a posterior part of the heel spring in all previously described embodiments of AFOs/orthotics. The cap 771 comprises an anterior slot 773 that is arranged to receive the posterior portion of the heel spring 703. A base of the anterior slot 773 is positioned at a height H above the distal side of the cap 771 and the internal dimensions of the slot 773 are determined to match the external dimensions of the posterior part of the heel spring. The cap 771 is made from a foam material, such as polyurethane or a similar material, such as EVA, as are the caps described below.

As shown in Figure 7E, the cap 771 can be placed over a heel spring 703 by inserting the posterior end of the heel spring 703 into the anterior slot 773. The cap 771 can be placed over the heel spring 703 to provide a heel height adjustment (i.e., to adjust the relative height difference between the anterior part of the soleplate 713 and the posterior part of the heel spring 703). The heel height adjustment provided by the cap 771 is dictated by the proximal-distal position or offset of the slot 773 in combination with the thickness of the cap 771 below the anterior slot 773, as indicated by H in Figures 7D and 7E. Caps 771 with different thicknesses and slot 773 offsets may therefore be used to achieve different heel-height adjustments. The cap 771 may also be used to reduce the size of the proximal-distal gap 757. In particular, the amount by which the proximal-distal gap 757 is reduced will depend on the thickness of the cap 771 above the anterior slot 773. Hence, caps 771 of different thicknesses may be used to adjust both the heel-height and the size of the proximal-distal gap 757.

An advantage of the cap 771 is that it effectively shields the posterior portion of the heel spring 703 from direct contact with the heel portion of the soleplate 713. In practice, this avoids any uncomfortable or potentially damaging direct contact between the two during use of the AFO/orthotic. Furthermore, since the heel spring 703 is typically made of a thin material, the cap 771 may be placed over the posterior portion of the heel spring 703 as a protective cover to protect the shoe into which the AFO/orthotic is placed from being damaged by the heel spring 703.

Figures 8A-8F show an alternative embodiment of a removable heel cap 871 that is arranged to be placed over a posterior end of a heel spring 803. The cap 871 comprises a lower portion 875 and an upper portion 877. The upper portion 877 comprises an outer rim 879 protruding from the cap 871 in a proximal direction and is arranged to receive the heel portion 813H of a soleplate 813. The lower portion 875 and the upper portion 877 are integrally formed and joined at their anterior-most ends to form a diminishing gap 857 between the lower portion 875 and upper portion 877. The cap 871 comprises an anterior slot 873 in the lower portion 875 arranged to receive the posterior end of the heel spring 803. The anterior slot 873 is positioned at a height H from the distal side of the cap 871, in a similar manner to the anterior slot 773 of the removable heel cap 771 of Figures 7A-7E.

The cap 871 can provide for a reduced proximal-distal gap between the heel spring 803 and the heel of the soleplate 813. As shown in Figure 8E, when the cap 871 is applied to an AFO (or orthotic), the size of the proximal-distal gap between the heel spring 803 and the heel of the soleplate 813 is effectively reduced to the size of the gap 857 of the cap 871. The cap 871 can therefore provide for a reduced gap depending on the overall thickness and dimensions of the cap 871. The cap 871 can also provide for an adjustment of the heel spring's 803 stiffness characteristics. The stiffness characteristics of the heel spring 803 may be altered based on the stiffness of the material used to form the cap 871, combined with the size and flexibility of the integral joint between the lower 875 and upper portion 877.

Similar to the heel cap 771 of the previous embodiment, the cap 871 provides for a heel height adjustment dictated by the proximal-distal position or offset of the slot 873 in combination with the thickness of the lower portion 875 below the slot 873, as indicated by H. For example, Figure 8F shows a cap 871 with a relatively thicker lower portion 875, which thereby increases the heel height H.

Furthermore, the cap 871 also provides shielding and protection between the heel spring 803 and the soleplate 813 or a user's footwear as previously described.

Figures 9A-9E show an embodiment of a reversible heel cap 971 arranged to be placed over a posterior end of a heel spring 903. The cap 971 comprises a first major surface 977 and second major surface 979. The first major surface 977 is substantially flat. The second major surface 979 comprises a posterior protrusion 975 that forms an area of increased thickness at a posterior end of the cap 971. The cap 971 comprises an anterior slot 973 arranged to receive the posterior end of the heel spring 903. The anterior slot 973 is positioned at a vertical distance Hl from the top of the protrusion 975, and at a vertical distance H2 from the flat major surface 977, as shown in Figure 9B.

Figure 9D shows the reversible cap 971 placed over the heel spring 903 in a first position, where the protrusion 975 faces downwards and the first major surface 977 faces upwards. In this position, the protrusion 975 provides an increased heel-height adjustment. The heel height adjustment made by the cap 971 is dictated by the thickness of the protrusion 975 relative to the anterior slot 973, as indicated by Hl. In this first position, the cap 971 may also reduce the effective size of the proximal-distal gap 957 depending on the distance H2. This reduction will be relatively minor if the thickness H2 is small. However, in some embodiments, the cap 971 may have a greater thickness H2 so that the proximal-distal gap 957 is further reduced.

Figure 9E shows the reversible cap 971 placed over the heel spring 903 in a second position, where the protrusion 975 faces upwards and the first major surface 977 faces downwards. In this position, since the protrusion 975 is facing upwards, the effective size of the proximal-distal gap 957 is reduced in proportion with the distance Hl. In some embodiments, depending on the material of the protrusion 975, the protrusion 975 may act as a buffer between the heel portion of the AFO/orthotic and the heel spring 903 to modify the stiffness characteristics of the heel spring 903. In the second position, the heelheight adjustment provided is based on the distance H2. In the present embodiment, the heel-height increase provided in the second position is relatively small. However, in some embodiments, the cap 971 may have a greater thickness H2 so that the heel height is further increased in the second position.

A user may therefore use the same reversible cap 971 to adjust the heel height and the size of the proximal-distal gap 957. In both positions of the cap 971 shown in Figures 9D and 9E, the cap 971 also provides shielding and protection between the heel spring 903 and the soleplate 913 or a user's footwear as previously described.

The orthotics 100, 200, 300, 400, 500 and 600 according to the embodiments of the invention are manufactured as described below. Manufacture of these laminated orthoses is a multi-stage process. Firstly, a cast is taken of the user's limb. When the cast is taken the ankle is usually in a slightly plantar flexed position. A wet lay-up technique is then used to create the rigid shell 101, 201, 301, 400. The dynamic struts 204 on the rear of the third embodiment orthotic 200 may be added at this stage.

The final step is to shape and finish the rigid shell 101, 201, 301, 400 as required. Although it is possible to include a heel spring in the wet lay-up, the material properties that can be achieved using a compression or press clave moulding and the extra features available through the use of a detachable heel spring 103, 203, 503, 603 mean that it is advantageous to form the rigid shell 101, 201, 301 with an internal anchor plate 125, 225, 525, 625 that can be used to mount a separate heel spring 103, 203. 503, 603. The anchor plate 125, 225, 525, 625 is positioned appropriately on the cast prior to lamination, which may require some local modification to the cast to provide a stable mounting which does not cause discomfort to the user. Once moulded in place, the anchor plate 125, 225, 525, 625 acts as a guide for drilling the final attachment bores 129, 139, 153, 529, 539, 567, 629, 638, 653.

Various modifications will be apparent to those in the art and it is desired to include all such modifications as fall within the scope of the accompanying claims.

For example, in the AFOs 100, 200, 500, 600, screws are used to releasable mount the heel spring to the soleplate. In other embodiments of the invention other fixing devices may be used. It also will be appreciated that although the lower surface of the depression is described as being substantially flat, the lower surface of the depression may be of any shape or contour as long as it is compliant with a resilient member for coupling. For example, the distal surface may be ribbed or jagged, to enhance grip between these two parts.

In an alternative arrangement a tapered or wedge-shaped shim or spacer of variable dimensions can be inserted between the heel spring and the rigid shell to adjust both the heel height and proximal-distal gap of the AFO/orthotic, by adjusting an angle between these two parts where they are joined. This may be achieved by inserting a uniform thickness shim between the heel spring and the rigid shell in a default arrangement when the AFO/orthotic is assembled; loosening or removing the screws to remove shim; inserting a wedge-shaped shin; and tightening the screws to hold the replacement shim in place and alter the angle between the heel spring and the rigid shell.

More than two screws may be used in the coupling arrangement with a corresponding number of holes. For example, three holes may be used. Correspondingly, in alternative embodiments, there may be variations of slots.

Various materials are mentioned above in relation to the construction of the shells 101, 201, 301, 401 and heel springs 103, 203, 303, 403, 503, 603. The skilled person will understand that these parts can be made from composite material such as carbon fibre, injection moulded fibre reinforced plastic or other engineering plastic or thermoplastic. The parts may be made by moulding, layering, additive manufacture or other suitable manufacturing methods.

Claims

1. A lower limb orthosis (100, 100', 200, 300, 400, 500, 600) comprising a soleplate (113, 213, 313, 413, 513, 613, 713, 813) and a heel spring (103, 103', 203, 303, 403, 503, 603, 703, 803, 903) extending from the soleplate.

2. An orthosis as claimed in claim 1, wherein the orthosis has a front foot portion (113F, 313F, 413F), a heel portion (113H, 313H, 413H, 513H) and a central portion (113C, 313C, 413C) between the front foot and heel portions, and the heel spring extends from the central portion.

3. An orthosis as claimed in claim 1 or 2, wherein the heel spring extends from the soleplate as a cantilever.

4. An orthosis as claimed in claim 1, 2 or 3, further comprising mounting means for releasably mounting the heel spring to the soleplate.

5. An orthosis as claimed in claim 4, wherein the mounting means comprises one or more threaded fastener (131, 531, 631) for attaching the heel spring to the soleplate.

6. An orthosis as claimed in claim 5, wherein the soleplate comprises a depression (121, 521, 621) and the mounting means further comprises an anchor plate (125, 225, 525, 625) which is accommodated within the depression.

7. An orthosis as claimed in claim 6, further comprising a cover piece (137, 637) for covering the anchor plate and for providing a continuous upper surface to the soleplate.

8. An orthosis as claimed in any one of claims 4 to 7, wherein the mounting means further comprises one or more washer (565) and/or nut (159, 559).

9. An orthosis as claimed in any one of claims 4 to 8, wherein the heel spring comprises one or more elongate bores (553) to allow longitudinal adjustment of the heel spring relative to the soleplate and optionally adjustment of heel height.

10. An orthosis as claimed in any one of claims 4 to 9, wherein the mounting means at the soleplate and the heel spring are flat at the position where the soleplate and the heel spring are mounted to each other.

11. An orthosis as claimed in any one of claims 4 to 9, wherein the mounting means at the soleplate and the heel spring are curved at the position where the soleplate and the heel spring are mounted to each other.

12. An orthosis as claimed in any one of the preceding claims, wherein the heel spring (103') is at least partially longitudinally split.

13. An orthosis as claimed in any one of the preceding claims, wherein the orthosis is an ankle-foot orthosis (100, 100', 200, 300, 500, 600) and the soleplate forms part of a shell (101, 201, 301, 501) which further comprises a proximally extending wall (133) for partially surrounding a foot and ankle, and optionally a shin, of a user.

14. An orthosis as claimed in claims 13, further comprising a proximal cuff (202) mounted to the shell by means of one or more posterior struts (204).

15. An orthosis as claimed in claims 14, comprising two or more posterior struts wherein the two or at least two of the struts have different stiffness.

16. An orthosis as claimed in any one of the preceding claims and further comprising a heel cap (771, 871, 971) mounted on the heel spring.

17. An orthosis as claimed in claim 16, wherein the heel cap is removably mountable on the heel spring.

18. An orthosis as claimed in claim 16 or 17, wherein the heel cap (971) is mountable on the heel spring in one of two position so as to adjust the height of the heel.

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19. An orthosis as claimed in claim 16 or 17 when dependent on claim 2, wherein the heel cap (871) has lower portion (875) which is mountable on the heel spring and an upper portion (877) which is disposable under the heel portion of the soleplate.

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20. An orthosis as claimed in any one of the preceding claims and further comprising a buffer disposed between the heel spring and the soleplate.

21. An orthosis as claimed in claim 20, wherein the buffer is resiliently deformable.

22. An orthosis as claimed in claim 20 or 21, wherein the buffer is removably disposed between the heel spring and the soleplate.