Knee Injury Case Studies
A 15-year-old gymnast has noted knee pain that has become progressively worse during the past several months of intensive training for a statewide meet. Her physical examination indicated swelling in and around the left knee. She had some decreased range of motion and a clicking sound on flexion of the knee. The knee was otherwise stable.
Studies
Results
Routine laboratory values
Within normal limits (WNL)
Long bone (femur, fibula, and tibia) X-ray
No fracture
Arthrocentesis with synovial fluid analysis
Appearance
Bloody (normal: clear and straw-colored)
Mucin clot
Good (normal: good)
Fibrin clot
Small (normal: none)
White blood cells (WBCs)
<200 WBC/mm3 (normal: <200 WBC/mm3)
Neutrophils
<25% (WNL)
Glucose
100 mg/dL (normal: within 10 mg/dL of serum glucose level)
Magnetic resonance imaging (MRI) of the knee
Blood in the joint space. Tear in the posterior aspect of the medial meniscus. No cruciate or other ligament tears
Arthroscopy
Tear in posterior aspect of medial meniscus
Diagnostic Analysis
The radiographic studies of the long bones eliminated any possibility of fracture. Arthrocentesis indicated a bloody effusion, which was probably a result of trauma. The fibrin clot was further evidence of bleeding within the joint. Arthrography indicated a tear of the medial meniscus of the knee, a common injury for gymnasts. Arthroscopy corroborated that finding. Transarthroscopic medial meniscectomy was performed. Her postoperative course was uneventful.
Critical Thinking Questions