FIELD OF THE INVENTION

The invention relates to correction of foot or ankle conditions and, in particular, to a method of performing corrective foot or ankle surgery and an apparatus for use with the surgery.

The invention has been described with reference to corrective ankle surgery and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this application and is applicable to foot and lower leg surgeries.

BACKGROUND OF THE INVENTION

The foot and ankle of the body of a person is a precise and complex structure. There are, in each foot, 26 bones, 33 joints of articulation and over a 100 tendons, muscles and ligaments. Serious feet and ankle injuries requiring surgical repair are all too common. These can be caused by a host of factors such as trauma or excessive loading, foot deformities, arthritis, and poor movement patterns when conducting everyday activities.

In view of the complexities of foot anatomy and precise loading requirements for proper use, it will be appreciated surgical repair can be anything but straightforward. For example, when a foot or ankle includes multiple fractures such as in the foot arch or the calcaneus to which the plantar facia anchors. In such cases, the foot or ankle by virtue of the fractures (or any other problem providing similar symptoms) is moved or deformed into an undesirable state whether at rest or under some load.

When foot surgery is performed it occurs in a sterile operating room theatre on an operating table. The patient can be laying either prone (facing down) or supine (facing up) on the operating room table. So far as surgeries are conducted with the patient under anaesthetic (most often a general) the bones of their foot are at rest where the structures within the foot are relaxed. This is known to be problematic for foot and ankle surgeons because the foot is not in natural alignment during surgery.

Often the surgeon is reliant upon their experience to simulate foot alignment intra-operatively to position the foot. That is, based on significant training and practical experience, surgeons essentially improvise and align the foot as they expect it to be arranged when bearing weight. This may lead to malposition which can impact the fusion rate of bone fractures being repaired and affect the final outcome of the surgery for the patient. When fusions are performed, the articulation of the joints is extremely important for, not only walking and other everyday activities, but also the effect this has on the structures above the foot that are affected by the foot's position and alignment. It is well known that if one or both feet are in poor alignment, it can cause excessive, internal or external rotation which puts increased loading on the ankles, knees, hips and back.

GENESIS OF THE INVENTION

The genesis of the invention is a desire to provide a foot &/or ankle surgical method and apparatus therefor that will overcome one or more of the disadvantages of the prior art, or to provide a useful alternative.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a method of forming a surgical foot orthotic, the steps including:

disposing a patient's foot or both feet in a weight bearing neutral position;

dorsiflexing the forefoot or forefeet of the patient such that patient's foot or feet are in or towards the Windlass configuration thereof;

forming a first orthotic correcting the stance of the patient in the weight bearing position with dorsiflexed forefoot;

scanning the first orthotic and forming an electronic image of the corrective load bearing surface thereof;

modifying the electronic image to include one or more guide apertures or cut-outs;

3-D printing a surgical corrected weight-bearing orthotic from the modified electronic image, said surgical orthotic including the one or more guide apertures or cut-outs.

According to a second aspect of the invention there is provided a surgical foot orthotic for the foot of a patient, the surgical foot orthotic being formed by the method according to the first aspect of the invention.

According to a third aspect of the invention there is provided a method of performing foot and/or ankle surgery on a patient in need thereof, the method comprising the steps of:

forming a surgical foot orthotic as defined in any one of paragraphs 1 to 7;

disposing the surgical foot orthotic about the foot of the patient and positioning same so as to manipulate bone articulation and joint congruency and establish the foot of the patient in the Windlass mechanism, or substantially as if the Windlass mechanism is engaged and the foot and bones of the foot are in the neutral or aligned position;

conducting a surgery on the foot and/or ankle of the patient whilst the surgical foot orthotic is disposed about the foot.

According to a fourth aspect of the invention there is provided, in a foot and/or ankle surgery of a patient, the use of a weight-bearing stance corrected foot orthotic adapted to be used on the foot of an anaesthetised patient in the supine or prone position, the weight bearing stance corrected foot orthotic adapted to dorsiflex the toes of the forefoot of the patient an angle of between 30° to 50° to the plane of the foot.

According to another aspect of the invention there is provided a method of performing foot and social ankle surgery on a patient in need thereof, the patient having a damaged foot requiring surgery and a foot not requiring surgery, method comprising the steps of:

forming a reference foot orthotic of the patient's foot not requiring surgery, the steps of forming the reference foot orthotic including:disposing a patient's foot not requiring surgery in a weight bearing neutral position;dorsiflexing the forefoot of the patient such that patient's foot is in or towards the Windlass mechanism thereof;forming a first reference orthotic correcting the stance of the foot of the patient not requiring surgery in the weight bearing position with dorsiflexed forefoot;scanning the first reference orthotic and forming an electronic image of the corrective load bearing surface thereof;creating a mirror electronic image of the first reference orthotic such that the electronic mirror image is adapted to support the foot of the patient requiring surgery;modifying the electronic mirror electronic image of the first reference orthotic to include one or more guide apertures or cut-outs;3-D printing a surgical corrected weight-bearing orthotic from the modified mirror electronic image, said surgical orthotic including the one or more guide apertures or cut-outs;

disposing the 3-D printed surgical corrected weight-bearing orthotic about the foot of the patient in need of surgery;

positioning the 3-D printed surgical corrected weight-bearing orthotic to manipulate bone articulation and joint congruency and established the foot of the patient in need of surgery in the Windlass mechanism, or substantially as if the Windlass mechanism is engaged and the foot and bones of the foot requiring surgery are in the neutral or aligned position;

conducting a and invasive surgical procedure on the foot and/or ankle of the patient requiring surgery whilst the 3-D printed surgical corrected weight-bearing orthotic is disposed about the foot.

It can therefore be seen that there is advantageously provided a method of forming a surgical foot orthotic and production of an orthotic to correct the position and alignment of the foot of the patient in advance of a surgical procedure that helps the surgeon align the bones of the patient's foot as the surgery is being performed. When used with a method of performing surgery, this minimises the subjectivity and guesswork of the surgeon when aligning a foot during surgery. Furthermore, it will also allow for more predictable and repetitive surgical outcomes which benefits all parties. The use of the formed orthotics not only significantly assists the surgeon with position of the foot and hence the quality of the surgical procedure but also saves the surgeon time in achieving a desirable outcome. This also speeds up the time spent in surgery ultimately leading to an operative cost savings.

Yet further, in the preferred embodiments, a full length corrected surgical foot orthotic was used, with the forefoot portion angled at approximately 45 Degrees to the plane of the foot to assist in establishing the Windlass effect of the foot. Having the toes dorsiflexed, in conjunction with the corrected weight bearing neutral foot position provides a surprising improvement in conduct and outcome of foot and ankle surgeries to assist and maintain the best possible bone articulation and joint congruency of the foot.

