Do I Have a Femoral Neck Stress Fracture?

Navigating hip pain can be challenging for runners.

Ranging from a mild pinch to pain forcing you to limp to the nearest set of crutches, hip pain can frustrate both athletes and providers. A lot of things can cause your hip to hurt. I want to zoom in on a specific injury we need to do a better job of diagnosing and treating: femoral neck stress fractures (FNSFs).

What is the femoral neck?1

The femoral neck connects the femoral head (where your hip attaches to your pelvis) to the femoral shaft (most of your upper leg). The bones of your lower body are designed to absorb the forces of running and help you propel from one leg to the next. Every time your foot hits the ground, your femoral neck has to slightly deform, like bending a wishbone at Thanksgiving, absorbing 3-5 times your body weight. Talk about a tough job!

If you are making steady progress in training, your bones will likely adapt to these forces. Unfortunately, these forces can be too much, leading to a bone stress injury (BSI).

The femoral neck is divided into medial (inside of your thigh) and lateral (outside of your thigh) portions. These two separate regions are uniquely designed to handle different forces. The lateral neck deals with tensile forces like a band being stretched. The medial neck deals with compressive forces like a bug being squished on the ground. Your femoral neck is uniquely designed to handle this unique combination of forces without breaking.

If you are progressing your training too quickly, or if your bones aren’t in a good place to begin, you can develop a BSI in your hip2. Cracks can develop in the femoral neck, swelling occurs, and you start reporting pain and tightness throughout your groin, or anterior/lateral hip.

It’s much more common to have a stress fracture develop in the medial femoral neck because of the femur’s unique anatomy. When you run, a greater percentage of each impact travels through the inferomedial femoral neck compared to superolateral femoral neck.

As these injuries progress, it often becomes difficult to walk, stand, and definitely run.

Why should I be concerned?

Broken bones happen all the time. Last summer, my 6-year-old ate a bunch of nachos and slipped off the monkey bars snapping his radius. A couple of weeks in a cast and he was good to go.

Shouldn’t we approach these in a similar way?
Rest for a bit and the bone should heal itself right?
Not so much.

Each bone in your body has a unique blood supply. Your arteries and veins travel across, around and through your bones supplying key nutrients and removing unwanted substances. Some bones have a better blood supply than others.

As we zoom in on the femoral neck, you’ll notice your circumflex arteries wrap around the femoral neck and supplies blood to your femoral head. If a fracture occurs, and that fracture displaces (moves), the fracture can sever that artery and causing femoral head to die 3. Ouch!

Why would I need surgery?

Adapted from Robertson et al.

Depending on your unique flavor of fracture, you may need to go under the knife 🔪. Surgery can allow the fracture to heal and prevent unwanted complications forcing you to retire your running shoes. The above table highlights the decision-making process for if a runner needs surgery. A few key variables they consider are…

  • 📍 The fracture location (medial versus lateral femoral neck)
  • 📏 The size of the fracture (greater or less than 50%)

Now that you are terrified you have one of these, let’s go through how these present in real life.

What does a femoral neck stress fracture sound like?

There are a lot of potential causes of hip, groin, or thigh pain4. When a runner has hip pain, it’s crucial to rule out a potential BSI. I see a few specific presentations with FNSFs that hopefully help you differentiate a BSI from something else.

BSI’s will often report pain with weight-bearing that lessens with non-weight bearing. A runner will say their hip hurts with running, walking, standing, and weight-bearing exercises, then feel better when sitting. There won’t be a specific mechanism of injury and they generally don’t report pain with different hip positions (sitting, stretching, etc.).

I’m also concerned if pain persists with day-to-day tasks even though a runner stops running5.

Aside from what they say, there are two clinical pears I’ve seen consistently with these injuries.

Clinical Pearl #1: Pain with Unloading

Runners with hip stress fractures consistently report pain with taking weight off the affected leg. This is counterintuitive to what you would expect. It makes more sense to get a spike in pain with squatting, going up steps, or balancing on the affected side. Runners may report some pain with those activities, but will often report a big increase in pain as they return to having two feet on the ground.

I highlight how this presentation looks in practice in this video 👇.

Clinical Pearl #2: Lateral Shift

This normally looks like someone is “stuck sideways”.
In school, you’re taught this happens when someone has lumbar disc pathology (i.e. bulging disc, disc protrusion, etc.). I’ll see this presentation often with stress fractures of the femur. Specifically, when they put weight on the affected hip they will shift or spend less time on that leg. It normally looks like a limp that hasn’t resolved.

FNSFs are complex and serious!
I hope this blog has given you a better understanding of their early management. If you found this content helpful and you’d like to learn more about stress fractures, I’d love it if you picked up my Navigating Stress Fractures Guidebook.
You can check it out by clicking on the image below.

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References:

  1. Robertson G and Wood A. Femoral Neck Stress Fractures in Sport: A Current Concepts Review. Sports Medicine International Open 2017; 1: E58–E68
  2. Neubauer T and Lidder S. Stress Fractures of the Femoral Neck in Runners: A Review. Research in Sports and Medicine, 2016. 24 (3) 283-297.
  3. Harper W, Barnes M, and Gregg P. Femoral Head Blood Flow in Femoral Neck Fractures: An Analysis of Intraosseous Pressure Management. British Editorial Society of Bone and Joint Surgery. 73(1). 73-75.
  4. Thorborg K, Reiman M, Weir A, et al. Clinical Examination, Diagnostic Imaging, and Testing of Athletes With Groin Pain: An Evidence-Based Approach to Effective Management. J Orthop Sports Phys Therapy. 2018 Apr;48(4):239-249.
  5. Warden S, Davis I, and Fredericson M. Management and Prevention of Bone Stress Injuries in Long-Distance Runners. JOSPT. 2014. 44 (10). 749-765.

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