Tuesday, February 27, 2007
Thursday, February 15, 2007
The Lachman's test (aka Ritchie test) is the preferred method of assessing for instability of the anterior cruciate ligament. The patient is supine on the table with their knee flexed approximately 20-30 degrees. The examiner grasps the medial proximal tibia with one hand and the distal thigh with the other. The examiner then applies a posteromedial to anterolateral force to the knee, essentially pulling the tibia anteriorly on the femur. The amount of translation is compared bilaterally to determine the presence and/or extent of instability. Alternative methods have been developed to accomodate examiners with small hands and for use with patients with large extremities.
The Slocum Drawer test is used to assess for medial and lateral rotary instabilities of the knee. The exam is administered similarly to the anterior drawer test with the exception that the tibia is rotated medially and laterally to assess for anterolateral and anteromedial instability respectively. The knee is placed in approximately 90-degrees of flexion with the foot flat on the table. Thirty-degrees of medial rotation is applied to the tibia by rotating the foot and the examiner pulls anteriorly on the tibia to assess for anterolateral rotary instability. To examine anteromedial rotary instability the tibia is laterally rotated approximately 15-degrees and the tibia is once again pulled anteriorly. Results are compared bilaterally.
The Acute Patella Injury Test (aka Apprehension Test) is used to assess the possibility that the patient may have sustained a patellar dislocation which spontaneously reduced. This test provokes the same sensations which would have been present when the dislocation occured and therefore will elicit a reactive contraction of the quadriceps muscles by the patient in an attempt to avoid a recurrance of the dislocation. This reaction is referred to as an apprehension sign. The patient lies supine on the table with the knee in 20-30 degrees of flexion and the quadriceps relaxed. The examiner carefully glides the patella laterally observing for the apprehension sign. A positive test is the presence of this reaction by the patient.
The posterior sag test (also known as the gravity drawer test, drop back sign, or Godfrey's test) is used to assess posterior cruciate ligament laxity. The patient is supine with her hips and knees bent to ninety-degrees. The examiner supports the patient's legs at the ankles and observes for an indication that the tibia has shifted posteriorly (toward the table) as compared to the uninvolved knee.
The McMurray test is a test used to determine the presence of a meniscal tear. While the patient is supine on the exam table the examiner grasps the knee, placing one hand over the top of the knee with her thumb over one joint line and her index and middle finger over the opposite joint line. The examiner begins with the knee in full flexion and then medially and laterally rotates the tibia while paying attention for an audible click. The examiner then laterally rotates the tibia and extends the knee beyond 90 degrees. An audible click while preforming this maneuver can indicate a torn medial meniscus. To examine the lateral meniscus the examiner will return the knee to full flexion and apply a medial rotation to the tibia prior to extending the knee once again.