ABSTRACT
Flexion deformity of the knee is frequently encountered in paediatric orthopaedic practice. Flexion deformity of the knee can also develop following any form of acute or chronic arthritis. It is important to be aware of the underlying pathology that resulted in the deformity as treatment will have to be planned accordingly. Flexion deformity of up to 90° is of little consequence in a child who is wheelchair bound. More severe degrees of flexion deformity can make it difficult to sit comfortably in a chair. In neuromuscular diseases where weakness of the quadriceps occurs, unopposed action of the hamstring muscles can result in a flexion deformity of the knee. Initially, the deformity may be dynamic but, in due course, contracture of the hamstrings will develop. Spasticity of the hamstrings in upper motor neuron paralysis often produces flexion deformity of the knee. Protective muscle spasm due to a painful condition affecting the knee can produce a flexion deformity.
