Mucous Cysts


  • Swelling on the dorsal aspect of the finger over the DIP joint


  • Usually there is a degree of osteoarthritis in the end joint of the finger. A cyst forms between the extensor tendon and the side ligament, causing a soft tissue swelling, which can be felt and usually seen over the back of the hand.


  • The location and appearance of the swelling is usually diagnostic
  • X-rays can be performed showing degenerative joint.
  • The cyst sometimes causes a pressure groove on the nail plate, causing a nail deformity.
  • Occasionally an MRI scan or ultrasound will confirm the diagnosis.


  • Occasionally the cysts will rupture and heal by themselves, not requiring treatment
  • Surgical Treatment – either general or regional anaesthetic
  • The skin is opened up through an ‘H’ type incision on the back of the finger. The cyst is debrided from the degenerative DIP joint. Bony spurs are nibbled back.
  • If the joint is grossly arthritic and painful then a fusion procedure is normally performed.

Potential Complications

  • Infection, haematoma, wound breakdown
  • Stiffness to the DI P joint
  • Recurrence of the Cyst

Post Op Care

  • The patient is usually in a finger dressing post operatively
  • Occasionally a splint is used to protect the extensor tendon
  • Specialist review at ten days for wound inspection and stitch removal and at six weeks for clinical review and three months.
University Of Auckland Auckland Born Joint Surgery Fracs NZOA  University Of Auckland Auckland Born Joint Surgery Fracs