Clicking 1st IPJ

[Linh]

Dear Steve,

I had a 60 year old patient with a clicking 1st IPJ whenever he flexes this joint. I saw a thickened A2 and also thickened A1 (where there is no clicking but tendon bunching). In this case, it is clear the patient has trigger thumb from the level of A1, but is the clicking IPJ just part of this condition also? or is it more OA related? What would you call if there is no A1 thickening/Triggering but just a thickened A2 and clicking IPJ?

Best regards,
Linh

[Stephen Bird]

Hi Linh,

I think these are 2 seperate issues.
If there is tendon (FPL) bunching or triggering this is almost always caused by A1 hypertrophy and then some underlying FPL tenosynovitis and it will cause a clinical trigger.
In these cases we treat the tenosynovitis with a tendon sheath catabolic injection.
The key to this diagnosis is the abnormal FPL movement and clear evidence of bunching caused buy the A1 pulley.

The click in the IP joint I think is much less important and not associated with the pulley disease or the tenosynovitis.
The A1 is at MCP level not the IP level.
A click in the IP joint is really common and is usually just a nitrogen release inside the joint capsule. It causes a sharp click when flexed just the same as many joints around the body. It is usually asymptomatic and unrelated to pathology. If they have OA in the joint they may have symptoms, but the sharp sounding click is a red herring.
The nitrogen release is caused by creating negative pressure inside the joint capsule and nitrogen is released from the synovial fluid. If you scan it sometimes you can see the gas “flash” when it clicks.

Steve

[Linh]

Dear Steve,

I have not thought of that. I guess the Thickened A2 at the IPJ can be ignored also then since it is really just because of the nitrogen gas. I sometimes see nitrogen gas (as echogenic foci) within the ACJ and Post GHJ in the shoulder but they don’t obviously click. Thanks Steve!

[Stephen Bird]

Nice one,

You can see intra-articular gas in many locations and can even use it to our advantage. I call it native contrast.

A good example is the dorsal intrinsic scapholunate ligament where the gas bubbles help me to determine the status of the ligament. If you watch some of the wrist material you will see the trick.

Steve

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