Introduction

Intraosseous ganglia are benign lesions which usually occur in the metaphysis or epiphysis of long bones, in the near proximity of a joint. The first description of an intraosseous ganglion comes from Fisk in 1949. Since then, various authors have used different names for this type of lesion, like subchondral bone cyst and synovial bone cyst. The cause of this diversity is the difference in interpretation of their aetiology.

History & Physical Examination

Intraosseous ganglia have been observed somewhat more often in males than in females, predominantly in middle-aged adults. The lesions are most frequently located in the lower extremities, usually involving the distal tibia.
Patients present with intermittent pain, frequently increasing with activity. Sometimes local swelling is seen.

Diagnostic Imaging

Radiographically, the lesion appears as a well-demarcated circular to oval radiolucent defect, outlined by a rim of sclerotic bone. As can been seen in the image to the right, there is a connection between the subtalar joint and the cyst. Most likely a small localised cartilage defect in the subtalar joint caused local high pressure with cyst formation.
The size and location of the lesion determines the approach. Lesions of less than 1 cm in diameter are usually treated by an antegrade approach. Larger lesions can be treated with retrograde drilling from the sinus tarsi (for a medial lesion) anteromedial talus (for lateral lesion) or from posterior. We prefer the approach for most lesions. The technique that we describe here is a 2-portal hindfoot approach with retrograde drilling through the posterior talar process.

Surgical Treatment

By means of a two-portal endoscopic approach of the hindfoot with the patient in the prone position it is possible to visualize, debride and graft these large cystic lesions.

Post-operative rehabilitation

The patient can be discharged the same day of surgery and partial weightbearing. The patient is instructed to perform active dorsiflexion of the ankle to the neutral position (knee slightly bent). This exercise should be performed 2 or 3 days times per hour for the first days after surgery. The patient is instructed to elevate the foot when not walking to prevent edema. The dressing is removed 3 days post-operative. The period of partial weightbearing varies between 10 days and 6 weeks. For defects up to 1 cm, 10-14 days partial weightbearing is enough. Larger defects can possibly benefit from a longer period of partial weightbearing since the filling of the defect gets a better chance of maturing without maximal loading. Patients with limited range of motion are directed to a physiotherapist. Running is best to be postponed untill 3 month postsurgery. Sport resumption can on average be expected at 4-5 month post surgery. 

Recommended Literature

van Dijk CN, Scholten PE, Krips R. A 2-Portal endoscopic approach for diagnosis and treatment of posterior ankle and hindfoot pathology. Arthroscopy 16(8): 871-876, 2000.

Scholten PE, Altena MC, Krips R, Van Dijk CN, Treatment of a large intraosseous talar ganglion by means of hindfoot endoscopy. Arthroscopy 19(1): 96-100, 2003