POPLITEAL VASCULAR COMPRESSION IN A NORMAL POPULATION

Purpose: Positional popliteal artery obstruction is believed to be an important factor contributing to popliteal artery entrapment syndromes . This study was undertaken to define the positional anatomy and physi ologic condition of the vessels in the popliteal fossa in groups of hi ghly trained and normally active young men and women. We postulate tha t at least some symptom-free individuals can occlude the popliteal art ery with leg positioning. Methods: Seventy-two limbs were evaluated in 36 subjects. Symptom-free subjects were recruited in four groups: nor mally active men, normally active women, male competitive runners, and female competitive runners. All subjects underwent noninvasive testin g that included resting segmental limb pressures and Doppler waveforms and color-flow duplex imaging with the leg in the neutral position an d then with knee extension with active and passive dorsiflexion and pl antar flexion of the foot. Subjects unable to occlude the popliteal ar tery with positioning were then exercised, and studies were repeated. Magnetic resonance imaging, with magnetic resonance angiography, was c onducted on 14 subjects, with each leg studied in the neutral position and with active positioning. Results: Positional popliteal arterial o cclusion occurred in 38 of 72 limbs (53%). No intergroup comparisons w ere statistically significant. The response of each leg was symmetric in 89% of subjects. No subject who could not occlude the popliteal art ery at rest was able to do so with exercise. Magnetic resonance imagin g disclosed normal anatomy in all subjects and showed the location of popliteal occlusion to be at the level of the soleal sling, with posit ional compression by the soleus muscle, the lateral head of the gastro cnemius, the plantaris, and popliteus muscles. Conclusion: Popliteal a rterial occlusion can be induced in 53% of subjects with simple leg po sitioning caused by myofascial compression. This must be considered wh en evaluating patients for intervention on the basis of physiologic te sting of the popliteal vessels.