Vascular Supply to the Proximal Plantar Plate of Lesser Toe Metatarsophalangeal Joint is Primarily Supplied by the Attachment to the Metatarsal: A Nano-CT Microvasculature Study

Abstract

Category: Lesser Toes Introduction/Purpose: Lesser toe metatarsophalangeal (MTP) instability is implicated in common forefoot pain and deformities. The plantar plate is a major stabilizing structure of the MTP joint with instability frequently occurring after a tear or attenuation of this structure. Previous studies have demonstrated that the blood supply to the proximal plantar plate comes from both the metatarsal and the plantar fascia. Commonly, a McGlamry elevator is used to strip the plantar plate from the plantar surface of the metatarsal to improve exposure of the MTP joint. The vascular consequence of stripping the plantar plate from the metatarsal is not yet well understood. The purpose of this study is to quantify the relative contribution of blood supply to the proximal plantar plate from the metatarsal and plantar fascia. Methods: Twelve fresh-frozen human adult cadaver lower extremity specimens were utilized for this study, resulting in 35 lesser MTP joints that were studied. All specimens were between the ages of 18 and 65 years and had no history of diabetes, peripheral vascular disease, or connective tissue disorders. Specimens with a history of trauma to the foot or ankle, prior foot or ankle surgery, or evidence of clinical deformity of less toes upon inspection were excluded. The specimens were prepared as described previously in Finney et al. The anterior and posterior tibial arteries were perfused with a barium solution and counterstained with phosphomolybdic acid. The second through fourth MTP joints of 12 feet were imaged with nano-computed tomography (nano- CT) at 14-micron resolution. Reconstructed 3D and 2D CT images were utilized for analysis of the volume of vasculature along the metatarsal pedicle and plantar fascia of the proximal plantar plate. Results: Based on nano-CT imaging, the plantar plate specimen demonstrated microvascular infiltration at the proximal attachments of the metatarsal neck, interosseous muscles, periosteum, and plantar fascia (Figure 1). An average of 63.5% of the vascular supply to the proximal portion of the plantar plate entered from the metatarsal pedicle in 35 lesser toe specimens analyzed. The remaining 36.5% of the vascular supply entered from the plantar fascia. The second toes, third toes, and fourth toes had an average of 64.7%, 59.0%, and 67.1% of vasculature supply from the metatarsal pedicle, respectively. The average volume of vasculature from the metatarsal pedicle to the proximal plantar plate was 0.38 mm3, while the average volume of vasculature from the plantar fascia to the proximal plantar plate was 0.19 mm3. Conclusion: The vascular supply of the proximal plantar plate is supplied from both the metatarsal pedicle and plantar fascia. Using the McGlamry elevator for exposure of the MTP joint disrupts the dominant tributary for proximal plantar plate perfusion.