Recently I wrote an article on my favourite condition to treat (here if you missed it). The AC-joint can be easy to diagnose, treat and resolve and can give clinician and patient instant gratification. The antithesis is ‘a pain in the bum.’ Quite literally.
Buttock pain is tricky because there are many separate (and sometimes co-existent) conditions that can cause it. The pain is often vague and the clinical tests have poor specificity. Radiology scans are fraught with incidental findings in this region that may not be relevant to the diagnosis.
The most over-looked condition that can cause buttock pain is ischeofemoral impingement. I believe the most incorrectly over-diagnosed cause of buttock pain is ‘pyriformis syndrome’.
So what is ischeofemoral impingement?
Ischeofemoral Impingement (IFI)
IFI occurs due to an entrapment of soft tissues between the bony prominences of the ischium (the sit bone) and the lesser trochanter (near the top of the thigh bone). Usually it is a muscle called Quadratus Femoris (QF) that gets trapped. It was first published as a suggested cause of pain in post-surgical patients in 1977. When MRIs became mainstream, the occasional discovery of an inflamed QF was initially blamed on a muscle strain. Now, with increased use of MRI, it has become apparent that the inflamed QF finding on MRI tends to occur in people with no history of a muscle straining incident. It is also found almost entirely in women with a narrow gap between the ischeum and lesser trochanter. The proximity of the sciatic nerve to QF (see picture) means that nerve irritation can occur. This can lead to symptoms radiating down the back of the thigh and further into the leg.
The typical presentation
- Almost always female
- Vague one-sided buttock pain
- May radiate pain down the back of the leg or (less commonly) into the groin
- Can be aggravated by running
Treatment relies on making the correct diagnosis and successfully ruling out other causes.
In mild cases rest from aggravating activities and running gait re-training is all that is required.
In more severe cases, a corticosteroid injection (in the right spot!!) can settle the impingement and inflammation but a preventative strategy is still required to prevent its recurrence.
In extreme cases, surgery has been shown to be very effective.