What is Ischiofemoral Impingement?
Are you suffering from a pain in your lower buttock or ‘bum’ area? Maybe you’ve been told you might have Ischiofemoral Impingement?
Maybe you’ve been told that you have a proximal hamstring problem, but despite loads of hamstring rehab, it’s just not getting better?
Maybe you’re struggling to sit comfortably, or you’ve noticed you have to shorten your stride to be comfortable when walking?
You may have Ischiofemoral Impingement (IFI).
Ischiofemoral impingement is an uncommon condition, but it is commonly missed. Many patients struggle on with what they thought was a hamstring problem, or even sciatica, but don’t improve with treatment.
Most of the patients I meet who have IFI are dancers, rowers, and people with hypermobility.
What causes Ischiofemoral Impingement?
IFI is a mechanical problem. Deep in your buttock, resides a small muscle called quadratus femoris. It can find itself being sheared between two bony prominences – the lesser trochanter of the femur, and the ischial tuberosity (sit bone) in a zone called the ischiofemoral space.
Normally there’s plenty of anatomical space for quadratus, but sometimes Mother nature sets people up with some predisposing anatomical faults (such as ‘femoral anterversion’).
Dancers who spend a lot of time in turn-out (e.g. ballerinas), or people who are hypermobile and may rapidly take the hip into an extended and externally rotated position, can end up pinching quadratus femoris.
What are the symptoms of Ischiofemoral Impingement?
Most patients will describe a pain deep in their bum, which is close to the sit bone area. The pain spread a underneath, and into the inner thigh.
If you’re finding it increasingly unpleasant to sit, or find your yourself levering off that sit bone area, you might have IFI.
Some patients feel a deep snapping sensation in their bum when they’re striding out, or rotating the hip outwards.
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How is Ischiofemoral Impingement diagnosed?
After taking a proper history, it’s time to see how you move and what provokes your pain.
Interestingly, many patients describe that when they’ve seen clinicians before, they haven’t been able to pinpoint where the pain is coming from – and that’s no surprise when you consider that quadratus is deeply seated. It can be difficult to palpate this area, and often the signs for hamstring irritation, or a lumbar spine problem are negative.
You might have pain on long-striding, and also we can attempt to put a bit of squeeze on quadratus femoris to see if we can reproduce your pain. We can do this by getting you to lay on your side on the couch, and then (passively) extending your hip.
If you have symptoms and clinical signs that point to the possibility of ischiofemoral impingement, then an MRI scan is the next step to help confirm the diagnosis.
What are we looking for on the MRI scan?
Below is a cross sectional slice through the back of the hip area, and there is a narrowed space between the sit bone (ischial tuberosity) and the lesser trochanter. The ‘squashed’ quadratus femoris muscle is brighter than the surrounding soft tissues (because it’s inflamed), and sometimes we might see some muscle fibre tearing.
What is the treatment for Ischiofemoral Impingement?
Despite what you may read on the internet, the good news is that we can nearly always treat this problem in a conservative way.
Although IFI is a rare condition, I nevertheless meet at least one person a week with this problem, and so far, I’ve not had to refer a patient for surgery.
Mostly, really good rehab, plus a guided injection to help settle the area, is sufficient to get you comfortable and back to being active.
The injection treatment is typically a one-off, CT-guided corticosteroid injection that is carried out by a radiologist in hospital environment. (Quadratus femoris is tricky to get to with a shorter needle under ultrasound guidance, and I find that that patients who undergo the injection this way tend to do better.)
Rehab is all about getting good hip and pelvic control and strengthening the deep hip rotator muscles. It’s important that your rehab exercises don’t compound the problem by further compressing quadratus femoris, and you might also find it helpful to sleep with pillow between your knees at night time.
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