Knee in congenital short femur.

The abnormalities of the knee associated with congenital short femur (CSF) and proximal femoral focal deficiency (PFFD), have been recognized for many years. The emergence of new and more effective lengthening techniques that can correct major congenital leg length discrepancies has made the abnormalities of the knee much more relevant. Some investigators have reported a high incidence of knee subluxation and dislocation during lengthening procedures in patients with CSF, attributing the incidence to knee anomalies. We assessed knee function in a group of 24 patients with CSF. Detailed evaluation of knee stability showed that not all knees were unstable; even when knees were unstable, the degree of instability was highly variable. No patient complained of knee pain or other knee symptoms.