unique orthopaedic devices
CDS knee brace

Isolated Quad weakness? Have you considered a knee extension brace?


The aetiology of quadriceps weakness is vast, ranging from acquired or inherited progressive myopathy, injury, knee OA, to even atrophy due to prolonged immobilisation in a cast. This can have huge implications on gait compensations, simple tasks of sit to stand can become extremely difficult to perform, and the ability to recruit and selectively control the contraction at the correct phases in gait impaired.

Those who have isolated quadriceps weakness which after targeted physiotherapy to strengthen may not be able to return to full power or a level that allows function for ADL’s. Often quadricep weakness can be dealt with via orthoses, often a full leg knee ankle foot orthoses (KAFO), a locked knee brace, or a ground reaction afo (GRAFO) to facilitate knee extension and safety in standing and walking are utilised.

But what about those clients who are not going to be able to preserve strength due to a progressive myopathy, have reached their strength potential but are still below the threshold for a normal gait pattern. These clients often are at a modified oxford of 3/3+ whereby a KAFO could be over bracing, and locking the knee in swing increase further gait compensations. Alternatively a GRAFO too restrictive at the ankle for squatting or hindering sit to stand due to inadequate dorsiflexion also problematic.

CDS knee brace

CDS® Knee Brace Extension
Dynamic spring-loaded knee orthosis

For these cases we have had great success with the off the shelf  CDS Knee extension orthoses, principally used for dynamic stretching; it works equally well as a knee extension orthoses for those quadriceps weak patients. It is perfect for clients who are progressive / or rehabilitating due the adjustable spring assistance that can be dialled in precisely for just the right amount of assistance.

We especially liked the flexion stop kits as an added safety feature to prevent complete collapse when first getting trialling the brace, for any residual flexion contracture the hinge can accommodate this, and finally for sitting the assist can be turned off for comfort.

A recent client who had a good outcome had a successful excision of a soft tissue sarcoma in lower third anterior quad; utilising primarily the CDS during therapy acutely on high assist. In conjunction with therapists managed to incrementally dial down the assistance to a point whereby the client weaned usage to long dog walks to fend off fatigue, a persistent bad habit of forward trunk lean, and lack of full knee extension in late swing, and for this client made the CDS an invaluable aid.

The brace is off the shelf and takes only a few measurements to determine suitability, is easily adjustable for set up and donning,  lightweight,  available in paediatric sizes,  and custom options are available if required. It is a great OTS solution that is highly convenient across a broad quad weak client base.