The quadriceps (Q) angle is a clinical measure of the
alignment of the quadriceps femoris musculature relative
to the underlying skeletal structures of the pelvis,
femur, and tibia. It provides a reasonable estimate of the lateral
force vector acting on the patella with quadriceps contraction1
and the tibial-tuberosity position relative to the midline of the
trochlea. An excessive Q angle is considered indicative of
extensor mechanism malalignment and has been associated
with anterior knee pain, patellar subluxation or dislocation,
and lower limb overuse injuries.It is often used
as a requisite measure to identify candidates for surgery
and as a means to assess surgical outcome. Most recently,
an excessive Q angle has been implicated as a potential
risk factor for noncontact anterior cruciate ligament injuries in
female athletes.