What a joint injection is for
Two things, and both matter.
Treatment. A corticosteroid, usually with a local anaesthetic, placed into an inflamed joint reduces the inflammation and the pain it causes. In an irritated arthritic knee, an inflamed facet joint or a painful shoulder, this can be substantial.
Diagnosis. If numbing a specific structure abolishes the pain, that structure was generating the pain. This is genuinely useful information, particularly in the spine and the hip where several possible sources refer into the same area and imaging cannot distinguish between them.
How it is used here
Deliberately, and with something attached to it.
The failure mode of injection-led pain practice is easy to describe: the patient gets an injection, feels better, changes nothing, the effect wears off, and they come back for another. Three years later the joint is in a worse state, the injections work less well each time, and nothing about the underlying mechanics has moved.
Dr. D’Alessio is board-certified in Physical Medicine & Rehabilitation — the specialty whose entire subject is restoring function — and the injection is framed accordingly. It buys a window of reduced pain. The window is when the strengthening work becomes possible, and the strengthening work is what makes the improvement outlast the injection.
You will be told this at the appointment, because knowing what the injection is for changes what you do with it.
The appointment
Skin cleaned and numbed. The joint entered, with imaging guidance where the anatomy requires it. The medication placed. A small dressing. Around fifteen minutes in total, and you drive yourself home.
Take it easy for a day or two — no strenuous loading of that joint — then start moving it. A flare of ache in the first 48 hours is common and settles.
When an injection is not the answer
Some joints should not be injected repeatedly. Some pain is not coming from the joint at all. Some problems — a tendon in the middle of degenerative change, for instance — are made worse by steroid rather than better.
Where that is the case, you will be told, and offered what is actually indicated instead. A practice that responds to every painful joint with the same injection is not diagnosing anything.