Patient History
Left lateral knee pain in a 15-year-old boy who sustained a hyperextension injury while playing football 2 weeks prior.
Findings
Menisci:
Medial Meniscus: Intact.
Lateral Meniscus: Intact.
Ligaments:
Anterior Cruciate Ligament: Intact.
Posterior Cruciate Ligament: Intact.
Medial Collateral Ligament: Minimally swollen.
Lateral Collateral Ligament: Intact.
Posterolateral Corner Structures: Intact.
Posteromedial Corner Structures: Intact.
Extensor Mechanism:
Patellar Tendon: Focal fusiform thickening and increased intrasubstance signal of the proximal patellar tendon deep fibers, consistent with mild proximal patellar tendinosis or “jumper’s knee”. Mild hypertrophy of the tibial tuberosity and subtle thickening of the distal patellar tendon. No tendon tear.
Distal Quadriceps Tendon: Intact.
Medial Patellofemoral Ligament: Intact.
Medial and Lateral Patellar Retinacula: Intact.
Hoffa’s Fat Pad: Unremarkable.
Articulations:
Patellofemoral Compartment: Unremarkable.
Medial Compartment: Unremarkable.
Lateral Compartment: Nondisplaced subcortical fracture of the anterolateral femoral condyle as described below. Otherwise unremarkable.
General:
Bones: Nondisplaced subcortical (subchondral/medullary bone) fracture of the anterolateral femoral condyle with marked surrounding bone marrow edema. Location suggests valgus event. Overlying articular cartilage preserved. No physeal involvement. Femoral and fibular physis remain open. Tibial physis closed.
Effusion: None.
Baker’s Cyst: None.
Loose Bodies: None.
Soft tissue and neurovascular: Unremarkable.
Conclusion
1. Nondisplaced subchondral (medullary bone or spongy bone) fracture of the anterolateral femoral condyle epiphysis, with surrounding osteoedema. No physeal involvement, displaced macrofracture, or cortical step-off.
2. No traumatic medial or lateral meniscus tear. No cruciate or collateral ligament injury.
3. Mild jumper’s knee.
