Hip Flexor Pain. Why it’s usually F.A.I. (Femoroacetabular Impingement)

I feel a need to talk about hip problems! We are getting into the beginning of marathon season, and (as is traditional this time of year), I am seeing a lot of runners presenting with groin pain.

I’m willing to stick my neck out and say that most of the time when patients are being told (or have decided themselves) that they have“hip flexor pain”, that this is actually a misdiagnosis.

There, I’ve said it.

Now before you shoot me down and say “But Cath, I really, really have had a patient with a rec fem or psoas problem”, I’m going to say that in the majority of patients I see and assess, there’s a pretty high likely hood that we will rule out a flexor problem, and rule in F.A.I.
In the uncommon situation when I do meet a human with a really sore rectus femoris or an unhappy psoas, they are either a child or are post-op.


So, why do we cling to the myth of hip flexor pain?


Patients are sometimes conditioned into thinking it can’t be a hip problem, because they are either too young or haven’t had an event that would “tear” a hip labrum. More often than not, a tear in a labrum is attritional, not violent in its occurrence. Most patients would swear blind that it’s “where my hip flexor lives” and well, of course it is. Last time I checked, psoas and rec fem passed right over the front of the hip socket.


Why am I feeling particularly ranty about this?


Have you ever had a patient who really can’t get back to the level of being active that they want (despite all the best efforts to get that pesky hip flexor stretched and glutes firing?)

Patients can spend a lot of time, money and insurance, going on a merry-go-round, until someone eventually says to them, “maybe we should do some imaging?”
Let’s get one thing straight. F.A.I is a clinical diagnosis and just because there may be a cam bump or a labral tear on MRI, it doesn’t necessarily mean it’s causing an actual problem.

BUT, unless you are thinking there is a possibility it could be F.A.I, you won’t check it out in the first place.


When do I think a patient has F.A.I?

When they tell me a little story that goes something along the lines of;

“Well I’ve started to get this pain in my groin that’s fine at the time, but gets niggly after a run”.

“I mostly get it when I’ve been sat for a long time”.

“I don’t like getting in and out of the car”.

“I’ve noticed that certain yoga positions are getting a bit awkward now.”



If, when I examine them and they have a hip that is slightly “sticky” on log rolling the entire length of the leg (i.e. the hip doesn’t have a nice roll into internal rotation), or their hip that is subtly restricted to hip internal rotation and they’ve a positive impingement sign, F.A.I. should be first and foremost on the differential diagnosis list.

In these patients, MRI (3T) or ultrasound usually demonstrates a fairly immaculate looking Psoas and Rec Fem.

Hip block injection proves it to be F.A.I or disproves it to be F.A.I.; it’s as simple as that.


 Let’s stop calling it “hip flexor pain” and start calling it “a hip problem”.

 Then, we can do something about it.


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