Posts Categorized: Knee

Do you see the unusual finding in this adolescent’s patella?

This 17-year-old male has patellar pain in his right knee. The cause of his pain is somewhat unusual. What is the most common locale of patellofemoral osteochondritis dissecans? What is the best treatment in a juvenile? What is the underlying cause?   The unusual finding is stage 2 osteochondritis dissecans (OCD). Take note of the… Read more »

What is the appropriate treatment for this chronic fracture?

This 15-year-old has knee pain months after a collision injury. What do the arrows identify on the axial MRIs through the patella? Is it surgical? What are some options for treatment? The arrows point to large flaps and fragments of cartilage. These have resulted from a chronic osteochondral fracture that includes a defect extending through… Read more »

With no recent injury or surgery, what explains this woman’s knee pain?

This 35-year-old woman presents with pain and locking when bending joint in her right knee. She has no recent injury and no history of surgery to this knee. She has patellofemoral maltracking, but what is the most important finding? Answer: The most important finding is the septated cystic structure involving the upper fibers of the… Read more »

This patient has an ACL tear, along with what other injuries?

This 55-year-old male has right knee pain after a fall down an embankment. He has an ACL tear, but what other injuries are present in this complex case? What is indicated by the arrows? You are shown these five static images, plus a GIF rotating a sagittal series. This patient has an ACL tear (pink… Read more »

What’s the life-threatening finding in this knee case?

This 57-year-old male presents with a large mass. What is it? But, more importantly, on these axial water-weighted MRI images, what is the potentially life-threatening finding?   The high signal mass is a gastrocnemius semimembranous bursal cyst (one of the many types of Baker’s cysts). The life-threatening finding is the absence of flow phenomena in… Read more »

Is there cause for concern in this 10-year-old with knee pain?

This 10-year-old presents with right knee pain and swelling. There is no known trauma. What’s the most likely diagnosis? What is indicated by the arrows in the back of the knee? Is it concerning?   The diagnosis is Sinding-Larsen-Johansson syndrome or inferior patellar “apophysitis” (yellow arrow). The green arrows indicate lymph nodes, and they are… Read more »

A meniscus case with some dangerous verbiage

This 12-year-old female presents with left knee pain, and the clinician alleges meniscal tear. The initial read was noncommunicating tear, but is this the proper call? You are shown four gradient echo sagittal water-weighted images and one sagittal T1.   No, this was not the proper call! Save the whales and the menisci. It’s a… Read more »

White Blob Around ACL?

What does the mass “white blob” around the ACL imply in this case? Come up with your own answer, then scroll down to see my findings. Of course lesion is bright (except on T1), smooth oval and therefore cyst (actually a ganglion pseudocyst). Some refer to this as mucoid lesion of the ACL. ProScan Pearl:… Read more »