ABSTRACT
Anterior knee pain is commonest in adolescent girls and is frequently bilateral. It is usually caused by the increased pressure and stress on the patella associated with patello-femoral instability, patellar tilting or malalignment. It starts insidiously with anteromedial pain exacerbated by climbing stairs, squatting or sitting with the knees bent. The knee frequently gives way and may ‘catch’ or ‘grate’. Examination of the lower limbs may reveal femoral neck anteversion, genu varum or valgum, external rotation of the tibia and squinting patellae. A quadriceps angle (Q) of more than 20° is abnormal. Patellar tracking should be observed from full extension to 30° of flexion as the patella enters the trochlear groove. Patellar tenderness may be elicited and patello-femoral compression is likely to be painful.
