Subtalar joint injection (CT-guided)

Case contributed by Dai Roberts
Diagnosis not applicable

Presentation

Severe subtalar arthropathy. Image guided steroid and local anesthetic injection.

Patient Data

Age: 40 years
Gender: Male

Shown is a technically successful (posterior) right subtalar joint injection. 

The first set of CT images are for planning; they demonstrate severe osteoarthrosis of the posterior subtalar joint as evidenced by bone-on-bone contact, subchondral sclerosis, osteophytes and tiny subchondral cysts. Incidentally, a bone island is noted in the calcaneum on the lowermost image. 

In the second set of images, the needle enters from a superior approach (lateral) and iodinated contrast confirms an intra-articular position, filling the posterior subtalar joint. 

Case Discussion

There are three subtalar joints; anterior, middle and posterior.  Subtalar joint injections in clinical practice refer to the posterior subtalar joint.  Injections can be performed using ultrasound, fluoroscopy and CT, although ultrasound is less frequently performed.  In an end stage arthropathy where the joint is very narrow, intra-articular access can be challenging and CT can be useful in these cases.

Technical considerations include aiming to avoid the lateral tendons, peroneal longus and peroneal brevis, which will traverse the superior aspect of the posterior subtalar joint. 

The needle used in this procedure was a 25 gauge.  If intra-articular access is not initially successful, a smaller 27 gauge could be considered but they are less stiff and will bend easier.  A luer lock syringe is a must to prevent needle-syringe detachment.

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