Steroid injections are powerful medicine, but where would you put the needle to treat patellofemoral pain syndrome?

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Corticosteroids are hormones that are produced by your adrenalin glands. (Not adrenalin itself — that comes from another part of the adrenal glands, and it’s a catecholamine. Quiz later!) Broadly speaking, these hormones suppress immune function, dancing and balancing constantly and intricately with other hormones that stimulate immune function. And inflammation is a product of the immune system, so corticosteroids have a nearly miraculous effect on inflammation, pretty much nuking it wherever the two meet. But like nukes, they have a dark side: some harsh side effects. You can’t just willy-nilly soak your system in corticosteroids without paying a price. Many readers may have heard of the many unpleasant effects of the common corticosteroid, prednisone.

Targeted injections, on the other hand, are quite a bit safer. The small amounts of corticosteroids involved are just not enough to be a problem for the whole system. And so steroid injections are a handy way of delivering a potent anti-inflammatory effect right to the source of the problem — think of them as ibuprofen on, er, steroids.

This can work great when you know where the source of the problem is. The evidence showing that they work well for targetable inflammation is acceptable, and one injection is often enough in the case of iliotibial band syndrome (see Noble, Gunter) where the target is fairly clear and accessible, where the target is fairly clear and accessible. Unfortunately, this is precisely what is often not known about PFPS. Where do you put the stuff?

There is no research at all about the effectiveness of steroid injections for PFPS, and no wonder: there’s too many possible injection sites, too much uncertainty. Corticosteroid injections are usually suggested only by doctors who don’t really know what else to do, and think it might be “worth a shot.” Does that physician know where to put the needle? Probably not.

I’m all in favour of using steroid injections when there is a reasonably good reason to believe that you can target an inflamed tissue. But the problem with recalcitrant PFPS is that you almost never know what tissue the pain is coming from — and in many cases it’s deep inside the knee — so where do you inject?  It becomes not so much a shot in your knee as a shot in the dark, with risk factors.  I’m not completely opposed to it in dire cases where nearly anything is worth trying, but it’s a weak option at best.

There’s no harm in discussing it, but ask your physician for his or her thoughts on the location of the injection and the reasons for it, and be skeptical if there isn’t a healthy respect shown for the uncertainties. If you do try injections, and three of them do not pretty clearly do the trick, you should probably stop trying, as steroid injections can permanently damage connective tissues near the point of injection. For this reason, some doctors will refuse to do it at all, but most agree that 1–3 injections is no cause for concern.