Knee Injury Case Study
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
- One of the potential complications of arthroscopy is infection. What signs and symptoms of joint infection would you emphasize in your patient teaching?
- Why is glucose evaluated in the synovial fluid analysis?
- What are special tests used to differentiate type of Tendon tears in the knee? Explain how they are performed (Always on boards)
