Knee joint effusion on X‑ray: 6 real cases
Real, openly licensed radiographs showing knee joint effusion. Study what to look for, then open each case and read it yourself before revealing the answer.
What to look for
- On the lateral view, soft-tissue density distends the suprapatellar recess between the quadriceps fat pad and the prefemoral fat pad.
- In trauma, a fat–fluid level on a horizontal-beam lateral (lipohaemarthrosis) implies an intra-articular fracture.
- Effusion alone is non-specific.
Quiz yourself on lower limb images
Cases
Case #97150532Lower limb · Intermediate
Case #108068082Lower limb · Intermediate
Case #107956608Lower limb · Intermediate
Case #81046941Lower limb · Intermediate
Case #17605997Lower limb · Intermediate
Case #17606005Lower limb · IntermediateOther lower limb diagnoses
- Acetabular fracture
- Ankle fracture (lateral malleolus)
- Bimalleolar ankle fracture
- Calcaneal fracture
- Calcaneal spur
- Femoral shaft fracture
- Fifth metatarsal fracture (Jones / base)
- Hip (proximal femoral) fracture
- Hip dislocation
- Patellar dislocation
- Patellar fracture
- Pellegrini–Stieda lesion
- Stress fracture
- Tibial (and fibular) shaft fracture
- Tibial plateau fracture
Diagnoses come from each image's documented source. Credits and licences are shown on each case and on the image credits page.