Surgery: splint – brace – or bandage – Orthopedic bandage – Splint or brace
Patent
1995-03-13
1997-03-11
Dvorak, Linda C.
Surgery: splint, brace, or bandage
Orthopedic bandage
Splint or brace
602 23, A61F 500
Patent
active
056095686
DESCRIPTION:
BRIEF SUMMARY
TITLE OF THE INVENTION
The present invention relates to floor-reaction type ankle-foot orthosis.
BACKGROUND OF THE INVENTION
An anterior floor-reaction orthosis (AFRO) is a brace that prevents the ankle joint from dorsiflexing. In the case of a paralysed limb, without any brace, the ground reaction vector passes through the ankle joint because no torque can be transmitted. However, with an AFRO, the base of the ground reaction vector can be moved forward to the metatarsal region of the foot as shown in FIG. 1a. In this position the ground reaction vector acts ahead of the anatomical knee joint axis and thus stabilises the knee in extension without muscular action.
Traditionally, a paralysed leg is braced using a knee-ankle-foot orthosis (KAFO) that incorporates a mechanically lockable joint positioned at the side of the anatomical knee. In contrast, the anterior floor-reaction orthosis (AFRO) principle may be used to stabilise the paralysed leg without physically locking the knee in extension. This has the major advantage that during the swing phase of walking the knee can flex to gain ground clearance. In addition, this provides improved cosmesis and reduces weight and cumbrance. However, the AFRO only stabilises the knee on the condition that the ground reaction vector is ahead of the knee axis as shown in FIG. 1a. If the ground reaction vector should shift behind the knee as shown in FIG. 1b, then the knee would buckle and the leg would collapse if there were no knee extensor muscle action. Thus, the AFRO is only used or prescribed when the patient has sufficient control of his knee extensor musculature to avoid collapse in these situations. Alternatively, paralysed muscles may be electrically activated in response to such an incident as disclosed in U.S. Pat. No. 5,121,747.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved floor-reaction orthosis which obviates or mitigates at least one of the aforementioned disadvantages.
This is achieved by providing a moulded plastic orthosis shell formed to be in close approximation to the anatomical limb. The leg portion of the plastic shell includes an elastic calf strap for controlling plantarflexion and a detachable heel wedge is provided which allows the vertical alignment of the brace to be adjusted. The improved foot-ankle orthosis fits inside the patient's shoe.
In one arrangement the floor-reaction orthosis is moulded in a single piece of plastic with the leg portion being integral with foot portion and the elastic strap is fastened to the top of the leg portion and passes round the back of the calf. The brace is fabricated such that the foot portion is made in one angled position which is typically 10.degree. plantarflexion. This allows various heel wedges to be inserted beneath the heel to allow correct vertical alignment of the subject in the brace so that the correct ground reaction vector position is achieved. This permits accommodation of variations presented by different shoe heel heights.
The device is straightforward to fabricate and uses a thermoformed plastic sheet or fibre composite laminate which is made by thermoforming the plastic sheet over a plaster of paris mould of the patient's leg.
According to one aspect of the present invention, there is provided a floor-reaction orthosis comprising a below-knee moulded orthosis shell proportioned and dimensioned to be in close proximity to the anatomical limbs, said shell having a leg portion and a foot portion, said leg portion fitting over the anterior surface of the limb, and the foot portion being coupled to the leg portion to wrap around the foot, said leg portion having an elastic strap coupled thereto for fitting around the calf of the limb, said shell being moulded for a single ankle position of plantarflexion, said foot portion being adapted to receive separate heel means for providing, in use, correct vertical alignment of the subject in the orthosis whereby the correct ground reaction vector position is achieved.
The leg and foot portion are inte
REFERENCES:
patent: 4497070 (1985-02-01), Cho
patent: 5219324 (1993-06-01), Hall
Dvorak Linda C.
University of Alberta
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