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Difficulty: HardPediatric Musculoskeletal Disorders

A 1414-year-old adolescent male is brought to the emergency department immediately following a basketball game due to severe, acute right knee pain. He reports that while forcefully contracting his quadriceps to jump for a rebound, he felt a loud "pop" in his knee and immediately collapsed to the floor. He has been unable to bear weight since the injury. The patient has a 66-month history of localized pain over the right anterior proximal tibia that worsens with running, which his pediatrician previously diagnosed as a traction apophysitis. Vital signs are within normal limits. On physical examination, the right knee has a large, tense effusion. The patient is completely unable to perform a straight leg raise or actively extend the right knee against gravity. A distinct, palpable defect is noted just inferior to the patella, and the tibial tuberosity is exquisitely tender and appears proximally migrated. Radiographs demonstrate a displaced fracture fragment arising from the anterior proximal tibia. Which of the following is the most appropriate next step in the management of this patient?

  1. Orthopedic surgery consultation for open reduction and internal fixationAnswer
  2. B
    Application of a hinged knee brace and referral for outpatient physical therapy
  3. C
    Magnetic resonance imaging of the right knee to assess the cruciate ligaments
  4. D
    Reassurance that this is a typical exacerbation of traction apophysitis
  5. E
    Ultrasound-guided arthrocentesis and initiation of empiric antibiotics

Answer

The most appropriate next step is an orthopedic surgery consultation for open reduction and internal fixation of the displaced fracture.
This patient's presentation is diagnostic of a displaced tibial tuberosity avulsion fracture. Adolescents, particularly jumping athletes with a history of Osgood-Schlatter disease (traction apophysitis), are at increased risk for this injury due to chronic microtrauma weakening the apophysis. The forceful contraction of the quadriceps muscle during a jump transmits massive force through the patellar tendon, avulsing the tibial tuberosity. The hallmark clinical finding is the inability to actively extend the knee against gravity (extensor lag) accompanied by a palpable defect. Because the fracture is displaced and the extensor mechanism is compromised, conservative management is inadequate. The most appropriate next step is an orthopedic surgery consultation for open reduction and internal fixation (ORIF) to restore the anatomy and function of the extensor mechanism.

Step-by-Step Solution

1
Evaluate the patient's history and physical examination findings.
The patient has a history of Osgood-Schlatter disease and presents with acute pain, an inability to actively extend the knee, and a palpable defect after a jumping mechanism.
These findings are classic for a catastrophic failure of the extensor mechanism.
2
Interpret the radiographic findings in the context of the physical exam.
Radiographs confirm a displaced fracture fragment from the anterior proximal tibia, localizing the injury to the tibial tuberosity.
Adolescents with preexisting Osgood-Schlatter disease have a weakened tibial apophysis, predisposing them to avulsion fractures during forced quadriceps contraction.
3
Determine the appropriate management based on the severity of the injury.
A displaced tibial tuberosity avulsion fracture compromising the extensor mechanism necessitates surgical repair.
Unlike simple Osgood-Schlatter disease which is managed conservatively, a displaced avulsion fracture requires open reduction and internal fixation to restore knee function.

Key Concept

Displaced tibial tuberosity avulsion fractures represent a severe complication of Osgood-Schlatter disease requiring urgent orthopedic surgery for open reduction and internal fixation to restore the knee's extensor mechanism.
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Topics

Pediatric Musculoskeletal Disorders

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