- Injury to
the anterior cruciate ligament (ACL) usually results from rotational force on
a fixed foot.
often report the sensation of a "pop" in the joint.
- Pain and
swelling are immediate
is clearly evident within 1 to 2 hours.
- The knee
generally is held in an extended position, with marked reduction in the range
Anteroposterior instability of the knee can be assessed by the "drawer sign."
- patient in
a supine position
- hip flexed
flexed 90 degrees with the
- foot is
held in a fixed position on the examination table.
forward excursion of the tibia when force is applied behind the knee by the
examiner is highly suggestive of an ACL injury
the drawer test in a sitting position may result in a false-positive test
The ACL inserts
on the tibial spine, inside the knee joint. The tibial tuberosity is the
insertion for the quadriceps tendon, outside the knee joint. Tenderness would
not be expected over the tibial tuberosity after an ACL injury. There may be
associated severe collateral ligament damage, resulting in laxity and tenderness
over the medial collateral ligament, although this is not always present.
Baskin MN. Injury—knee. In: Fleisher GR, Ludwig S, eds. Textbook of
Pediatric Emergency Medicine. 4th ed. Philadelphia, Pa: Lippincott
Williams & Wilkins; 2000:339-347
Mercier LR. The knee. In: Practical Orthopedics. 4th ed. St Louis, Mo:
Mosby-Year Book, Inc; 1995:207-232