Pediatric emergency medicine trisk 0845 0845
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (89.72 KB, 1 trang )
hand. If the knee “opens up” laterally or medially more than the uninjured knee, the collateral
ligament is injured.
Posterior cruciate ligament injuries are extremely rare and usually result from
direct force on the tibial tubercle, pushing the tibia posteriorly on the femur. The
posterior drawer sign will be present in most cases (see Fig. 42.5 ).
The menisci are tough fibrocartilage pads that help distribute the body’s weight
over the femoral and tibial condyles. They can be injured when the knee is
twisted during weight bearing. The patient, usually older than 12 years, may
report a popping sensation and the feeling of the knee “giving out.” Outside the
acute period, the patient may report that the knee suddenly refuses to extend fully,
“locking up,” and then suddenly “unlocking.” Joint line tenderness is frequently
present (sensitivity 0.7 to 0.8, specificity 0.2) but must be differentiated from the
tenderness associated with collateral ligament injuries. An effusion is commonly
detected. Acutely, the injury may be difficult to diagnose because of diffuse pain
and significantly reduced ROM, making the classic McMurray’s sign difficult to
elicit (see Fig. 42.6 ). The Apley compression test (see Fig. 42.7 ) requires less
knee movement and may be easier for the patient to tolerate. Radiographs are
generally obtained to evaluate for other causes of the pain.
FIGURE 42.5 Testing for posterior cruciate ligament injury with the posterior drawer test.
With the patient supine and the knee flexed to 90 degrees, sit on the patient’s foot to stabilize it.
Attempt to force the tibia posteriorly. Posterior movement with no discrete endpoint or greater
on the injured than the uninjured side is abnormal and suggests a posterior cruciate ligament
injury.
