Abstract
Background: Although the anatomy and physiology of the venous circulation of the ankle and midfoot are well documented, the physiologic importance of forefoot mobility has not been reported in the literature. The question of this study was whether the first metatarsophalangeal (MTP) joint may operate, like the ankle, as a “pump” to encourage venous return. Methods: Forty-nine cadaver foot specimens were examined using dissection, plastination, vessel infiltration, and maceration, and radiographic (including venography, MRI, and magnetic resonance angiography) techniques. The anatomy and physiology were described and compared to the ankle joint. Forty patients had biphasic Doppler flow studies. Results: The major finding was the medial drainage of the plantar venous sinus, which is fibrotically bound to the joint capsule. Functional venous valves were evident distally and within fibrous vascular lumens. Mobilization of the first MTP joint led to compression and emptying of the veins. Passive mobilization of the first MTP joint led to an average flow increase of 55% ± 7 (p < 0.0001), while active movement led to an average increase of 78% ± 7 (p < 0.0001). Conclusions: Our described connection between the joint capsule and veins indicates a “toe-ankle pump” with a significant increase of venous blood flow during motion of the MTP joint. Possible clinical applications for an external MTP pump include anti-edema or thromboprophylactic therapy, especially in patients with foot or ankle injuries. A new toe-pump has been designed based on these results.
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