Courtesy: Prof Nabil Ebraheim, Unviersity of Toledo, Ohio, USA

Ganglion Cysts Around the Knee

Ligamentous Ganglion Cysts

• Ganglion cysts arising around the knee, particularly from the ligaments, can cause:
  • Knee pain
  • A sensation of tightness
  • Mechanical interference with knee flexion and extension
• Patients may particularly complain of pain and tightness during knee flexion.
• These lesions can be clearly demonstrated on MRI.

Intraosseous Ganglia

• An intraosseous ganglion is a benign subchondral radiolucent lesion that typically occurs in the absence of significant degenerative arthritis.
• Common locations include:
  • Epiphyses of long bones
  • Medial malleolus
  • Femoral head
  • Proximal tibia
  • Carpal bones
• Intraosseous ganglia may occasionally cause pain.

Radiographic Features

• On plain radiographs, an intraosseous ganglion typically appears as:
  • A well-demarcated, solitary radiolucent lesion
  • A sclerotic or well-defined margin
  • No obvious communication with the joint
• MRI may demonstrate:
  • A solitary or multiloculated cystic lesion
  • Well-defined margins
• Bone scintigraphy is usually not significantly hypermetabolic (“not hot”).

Proximal Tibiofibular Joint Ganglion Cyst

• A ganglion cyst arising from the proximal tibiofibular joint can cause compression of the common peroneal nerve.
• Clinical manifestations may therefore include symptoms related to common peroneal nerve compression.

Treatment

• The usual treatment is:
  • Decompression and excision of the cyst
  • Decompression of the affected nerve, when nerve compression is present
• In cases of recurrent cyst formation, fusion (arthrodesis) of the proximal tibiofibular joint may be considered, particularly when recurrence occurs following cyst excision.