Orthotics and prosthetics

An orthosis supports a limb that is still there. The most common is the ankle-foot orthosis, which holds up a foot that drops when walking — the pattern seen after stroke, after nerve injury and in a number of neurological conditions. Others hold a wrist in a working position, control an unstable knee, or support the trunk after spinal surgery.

A prosthesis replaces a limb that has been removed. The device is the smaller half of the problem; the larger half is the residual limb it sits on and the training that follows.

The residual limb changes shape considerably in the months after surgery as swelling settles, so an early socket will not fit later 1. Work begins before any device exists: shaping and desensitising the limb, keeping the joint above it from stiffening, and building the strength that will carry the prosthesis.

A temporary prosthesis is usually fitted first and adjusted repeatedly as the limb settles. The definitive one follows. Componentry is matched to what the person will actually do — the most advanced knee available is the wrong prescription for someone who will use it indoors.

A device that hurts is not worn, and a device that is not worn does nothing. Most abandonment traces back to three things: a socket or brace that was never comfortable, no training in putting it on and using it, and no one available to adjust it when the limb or the problem changed.

So fitting is not the end of the episode. Skin is checked, the fit is reviewed as things change, and walking is retrained with the device rather than assumed to follow from having it.

A device is prescribed when it makes a specific task possible or safe — clearing the floor when walking, holding a joint out of a deforming position, protecting a healing structure. It is not prescribed as a substitute for strength that could be trained back.

Braces worn permanently for problems that respond to exercise tend to make the underlying weakness worse. Where a device is a temporary measure we will say so, and say what has to change before it comes off.

A device that leaves redness that does not fade soon after removal does not fit, and in someone with reduced sensation that redness is the only warning before a pressure injury.

Patients and families are taught to inspect daily and told exactly what to report. This is the single most preventable complication in device use.

Devices wear out, limbs change, and children grow out of everything. A plan that covers only the initial fitting leaves people with an unusable device and no route to a replacement.

We state expected replacement intervals before fitting, and for children we plan around growth rather than treating each refitting as a surprise.