Author: Marcus Fearing, MD
Co Author #1: Meg Gibson, MD
Co Author #2: Kevin Gray, MD
Co Author #3: Josh Go, DO
Senior Editor: Carolyn Landsberg, MD
Editor: Aubrey Armento, MD

Patient Presentation:
A 19-year-old male, Division I basketball player with
history of right knee ACL reconstruction three years prior as well as sickle cell trait, presented to the athletic training room with significant asymmetric right knee swelling with minimal pain. This developed one hour after a shoot-around without notable injury.

History:
He did not have an effusion two weeks prior at his pre-participation evaluation. During the first 2 weeks of practice, he reported mild pain with running, conditioning workouts, and weightlifting, but it was not preventing him from participation in collegiate basketball activity.

The patient's past surgical history included a right ACL reconstruction with tibial tendon autograft, partial medial and lateral meniscectomy, abrasion chondroplasty and micro-fracture of the lateral femoral condyle, and patellar shaving.

Physical Exam:
Vital signs were within normal limits including regular heart rate and temperature.

Right Knee Examination:
Inspection: Significant swelling in comparison to the left knee. No overlying erythema or other skin changes.
Palpation: A large effusion was noted. Mild posterolateral joint line tenderness.
Range of Motion: Active range of motion showed 0 degrees in extension to 100 degrees in flexion.
Strength: 5/5 and equal bilaterally in knee flexion and extension.
Special Testing: Lachman test similar to the prior pre-participation exam. Negative anterior drawer test, McMurray test, Thessaly test, and valgus and varus stress tests.

Click here to continue. Challenge yourself by writing down a broad differential diagnosis before moving to the next slide.