How To Diagnose And Treat Exercise-Induced Leg Pain
Exercise-induced leg pain can be related to a number of etiologies, some more elusive than others. Differential diagnoses in the workup of exercise-induced leg pain should include musculotendinous injury, exertional compartment syndrome, popliteal artery entrapment syndrome, medial tibial stress syndrome (MTSS) and stress fracture.
Other less common causes of exercise-induced leg pain include lumbosacral radiculopathy, lumbosacral spinal stenosis, focal nerve entrapment, vascular claudication from atherosclerosis, venous insufficiency, neoplasm and various myopathies.
With these considerations in mind, let us take a closer look at the diagnosis and treatment of exertional compartment syndrome, popliteal artery entrapment syndrome, MTSS and stress fracture.
What You Should Know About Exertional Compartment Syndrome
An exertional compartment syndrome is due to a decrease in the compartment volume, which is related to increased muscle edema and capillary ingress. Compartmental pressure increases and this creates a pressure gradient, which is not favorable to arterial inflow. In turn, muscle hypoxia and eventual myonecrosis can result. Upon rest, a decrease in intracompartmental pressure occurs and arterial inflow returns, relieving myofascial ischemia and pain.
The diagnosis of an exertional compartment syndrome requires a high index of suspicion and further clinical investigation using a device such as a wick or slit catheter, a side ported needle (Stryker® manometer) or a simple needle to measure compartment pressures. In the clinic setting, physicians can test pre-exercise compartment pressures and then have the patient engage in exercise until the onset of symptoms. One can then remeasure compartment pressures immediately upon the cessation of activity. This often takes appropriate planning by the clinician and patient.
Intracompartmental pressures > 10 mmHg at rest and/or > 25 mmHg five minutes after exercise have been defined as abnormally elevated.1
Leg pressures that may indicate exercise-induced compartment syndrome are pressures > 30 mmHg one minute after exercise and/or > 20 mmHg five minutes after exercise. Leg pressures > 40 mmHg are diagnostic for exercise-induced compartment syndrome.1-3
The treatment for exertional compartment syndrome can include conservative care, which essentially is limitation of activity. Surgical intervention with decompression fasciotomy has a fairly high success rate of resolving symptoms.1 Traditionally, surgeons have performed open fasciotomy but endoscopic fasciotomy is also an option. Using an endoscope and fasciotomy blade, one can use minimal incisions that may facilitate recovery.
Key Insights On Popliteal Artery Entrapment Syndrome
Popliteal artery entrapment syndrome is less common than exertional compartment syndrome. The reported prevalence is 0.16 to 3.5 percent and occurs typically in young men 20 to 40 years of age who have well developed leg musculature.4 The condition can be due to abnormal positioning of the popliteal artery in relation to its surrounding structures. In turn, extrinsic compression leads to an irreversible lesion of the popliteal artery, such as aneurysmal dilatation, thrombosis or intimal thickening.
Typically, patients present with claudication symptoms that are often positional and exercise-induced, leg edema, aching pain, pain at rest, tiredness or calf cramping. Knee extension and/or hyperextension and a plantarflexed foot will elicit non-palpable distal pulses, and when the knee is neutral or slightly flexed, pulses are palpable.5-8