Hi, my name is Mike Henehan, and I'm a faculty member in the Stanford O'Connor Sports Medicine Fellowship Program. This case is interesting because it presents a classic diagnostic dilemma in evaluating lower extremity pain. The three things that you're worried about would be differentiating stress fracture from medial tibial stress syndrome from chronic compartment syndrome. History becomes very important in that with chronic compartment syndrome, there's very characteristic neurologic or pain patterns that occur at a specific distance into a run, let's say, or whatever the activity may be. That's because muscles will swell about 20% due to the increased blood flow, and in the fixed compartment in the lower leg, that can then compress neurovascular structures, and hence, you have to have the activity at a certain level to cause the swelling, and then you'll get your symptoms. That's very distinct from medial tibial stress syndrome or stress fractures, which tend to be symptomatic more frequently and earlier in the activity pattern and longer lasting. But there are some tricks on physical exam to help distinguish stress fracture and medial tibial stress syndrome. And if those are negative, then you think more of compartment syndrome if the symptom pattern fits that. So let me demonstrate those now for you. So one of the key things is the palpation pain pattern as you're doing your exam. So medial tibial stress syndrome tends to be a lot more diffuse, and so you'll get pain along a wider stretch of the anterior tibial surface, whereas a stress fracture tends to be more focused and a more discrete pain. So when you see that, what I do is kind of remember where I felt the most tenderness on the tibial surface, and then I have the patient slide down, and I perform what's called the fulcrum test. So I put that point right at the edge of the table, and then I just add a little distracting force down. And so I'm essentially levering the tibia as I do that. And if that elicits more pain, then I would be concerned for a possible stress fracture, because you shouldn't have that discomfort with medial tibial stress syndrome as commonly. Some people will use tuning forks. That's worth a try. I think the evidence is a bit mixed about it. But in studies, the 256 hertz tuning fork seemed to be the one that would elicit pain. And what you do is activate the tuning fork. You put it on the bone, and then away from the fracture, suspected fracture site. And if you get increased pain where you are worried there may be a stress fracture, then that would be a positive test.

2nd Edition, CASE 36

2nd Edition

Metabolic Disorders

lower extremity pain

stress fractures

medial tibial stress syndrome

chronic compartment syndrome

diagnosis techniques