Clinical Cases - Joints of the Lower Limb

The star running back of a college football team was cutting outside to evade a potential tackler and take advantage of a block when he was hit on the posterolateral side of his right knee by an opponent. At the time of impact, the running back's right foot was firmly planted as he was changing directions. The leg was severely abducted by the blow, and the knee buckled as the running back collapsed to the turf in severe pain. A stretcher was required to remove him from the field. He was then transported to the university hospital where the knee was thoroughly examined. Severe pain was localized to the medial side of the right knee, and a drawer test was positive. The running back's knee was determined to require surgery, and he was unable to return to the playing field until the following season.

Questions to consider:
  1. Based on the information given, what ligaments were probably injured?
    The medial collateral ligament and the anterior cruciate ligament were involved in this case. The localized pain medially suggests a medial collateral ligament injury and the positive drawer test indicates a ruptured anterior cruciate ligament.
  2. What other structures may also be injured?
    The medial meniscus is probably also damaged because it is attached to the medial collateral ligament. Undue stress from a blow to the lateral side of the knee usually results in tearing of both the medial collateral ligament and the medial meniscus.
  3. What is the drawer test?
    The drawer test involves firmly grasping the leg with both hands just below the knee with the thumbs on the tibial tuberosity. With the knee flexed, the examiner pushes and pulls the leg in a line parallel to the long axis of the femur. Excessive mobility anteriorly indicates a ruptured anterior cruciate ligament, while excessive posterior movement suggests a ruptured posterior cruciate ligament.
  4. What was the goal of surgical intervention?
    Surgery for an athlete (as in this case) would be aimed at repair of the medial collateral and anterior cruciate ligaments and the medial meniscus; however, in severe injuries, the medial meniscus may need to be removed entirely. Depending on the severity of the damage to the ligaments, transplants of ligaments or tendons from other locations (i.e. the patellar tendon) may be required to help stabilize the knee. In non-athletes, patients with anterior cruciate ligament damage often do not have the ligament repaired because it is not absolutely essential to knee stability and because repairs are not always successful. These patients are taught to compensate for the injury using their quadriceps muscles.
  5. Why does a blow on the lateral side of the knee usually produce a more serious injury than a blow to the medial side?
    Because the medial collateral ligament and the medial meniscus are attached, these structures are frequently injured together as a result of a blow to the lateral side of the knee. The same is not true for blows to the medial side of the knee. In this case, only the lateral collateral ligament is usually injured. The lateral collateral ligament and the lateral meniscus are not attached to each other, but are separated by the tendon of the popliteus muscle.

A paratrooper was taken to the hospital complaining of bad pain in the right foot caused by improper and forceful landing on her heel. Upon arrival at the hospital her injured foot was swollen, deformed and held rigid. AP, lateral and oblique x-rays were done, and an undisplaced fracture of the talar neck was shown. The orthopedic surgeon ordered a split plaster of Paris that should be reapplied when swelling settles.

Questions to consider:
  1. How would the talus get fractured as a result of a fall on the heel?
    The upward thrust of the calcaneus against the talus and tibia may fracture the talus.
  2. What other bones may fracture from such trauma?
    Calcaneus and lower end of the tibia.
  3. In this case, the surgeon should do a special examination of the vessels in the vicinity of the fractured talus. Which vessel is of importance in this respect?
    The dorsalis pedis pulse is important to be checked in such cases.
  4. What complication may arise from such a fracture?
    Avascular necrosis and non-union.