SAEM Clinical Image Series: Knee Pain

Oct 19, 20
SAEM Clinical Image Series: Knee Pain


A fifty-six-year-old male with a past medical history of legal blindness and remote right quadricep tendon rupture presents to the emergency department via emergency medical services (EMS) after a mechanical fall, complaining of left knee pain. According to the patient, he is in his regular state of health and was walking with his cane when he had a mechanical fall on the sidewalk after tripping on an unknown object and falling onto his left knee.

The patient did not hit his head, did not lose consciousness, and has no head, neck, or back pain. The patient states that he fell directly onto his knee and felt a popping upon hitting the ground, and remembers all events surrounding the incident. The patient was not ambulatory prior to coming to the emergency department.

Vitals: BP 123/78; HR 78; RR 16; SpO2 97%; Temp 36.6°C

General: Not in acute distress, normal appearance, and he is well-developed. He is not ill-appearing, toxic-appearing, or diaphoretic.

HEENT: Normocephalic, atraumatic, pupils are equal, round, and reactive to light, legally blind

Neck: Normal range of motion, neck supple, no neck rigidity or muscular tenderness, no tracheal deviation

Cardiac: Regular rate and rhythm, normal heart sounds, no murmur, no friction rub, no gallop

Chest wall/Pulmonary: Pulmonary effort normal, no respiratory distress, normal breath sounds, no stridor, no wheezing, rhonchi, or rales, and no tenderness to the chest wall

Abdominal: Soft, no mass, no tenderness, no guarding or rebound


  • Left knee swelling, left knee tenderness, inability to extend his left lower extremity
  • Tender hypertonic quadriceps muscle with contracture in the distal thigh, and no tenderness over the patella, no tenderness to tibial tuberosity or patellar tendon.
  • No bony tenderness to his tibial plateau, medial, or lateral aspects of his knee
  • Neurovascularly intact distally

Skin: Warm, dry, and capillary refill is less than 2 seconds.

Neurological: No focal deficit present.


The ultrasound shows:

  • A hypoechoic area and disruption of the quadricep tendon
  • Irregularity of the superior aspect of the patella, which is consistent with an avulsion fracture

Take-Home Points

  • Ultrasound can be valuable for the evaluation of extensor tendon ruptures [1].
  • Do not only look for the tendon disruption but also look for disruption of the surrounding bones and edema (secondary signs) [2].
  1. Bartalena T, Rinaldi MF, De Luca C, Rimondi E. Patellar tendon rupture: radiologic and ultrasonographic findings. West J Emerg Med. 2010;11(1):90–91. PMCID: PMC2850864
  2. Phillips, Kylee, MD, MBA, Costantino TG, MD. Diagnosis of Patellar Tendon Rupture by Emergency Ultrasound.Journal of Emergency Medicine. 2014;47:204-206. PMID: 24746910

Author information

Eric R. Friedman, MD

Eric R. Friedman, MD

Emergency Medicine
University of Maryland Medical Center

The post SAEM Clinical Image Series: Knee Pain appeared first on ALiEM.

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