A Comparison of Microvasculature of Normal versus Torn Lesser Toe Metatarsophalangeal Joint Plantar Plates Using Nano-CT Imaging

CATEGORY: Lesser Toes INTRODUCTION/PURPOSE: Recent surgical techniques have focused on anatomic repair of lesser toe metatarsophalangeal (MTP) plantar plate tears. MTP instability has been implicated in a number of common toe deformities as well as metatarsalgia. Recently, a study demonstrated that the microvasculature of the normal plantar plate is densest at the proximal and distal attachments. The purpose of this study was to compare the intact plantar plate microvasculature network to the microvasculature network of plantar plates in the presence of toe deformity using similar perfusion and nano-CT imaging methods. METHODS: Eight fresh frozen human cadaveric lower extremities with lesser toe deformities including hammertoe or crossover toe were perfused using a barium solution. The soft tissues of each foot were counterstained with phosphomolybdic acid (PMA). Then using nano-CT imaging the second through fourth toe metatarsophalangeal joints of 8 feet were imaged. These images were then reconstructed, plantar plate tears were identified, and eleven toes remained. The plantar plate microvasculature for these eleven toes was analyzed and calculation of vascular density along the plantar plate was performed. Using ANOVA analysis this experimental group was compared to a control group of 35 toes from cadaveric feet without deformity and the vascular density compared between quartiles of plantar plate length proximal to distal. RESULTS: Demonstrated in Figure 1, of the torn plantar plates the average percent vascular density (vascular volume/tissue volume) in the first quartile of length (proximal to distal) is 0.365 (SD 0.058) compared to 0.281 (SD 0.036) for intact plantar plates; in the second quartile it is 0.300 (SD 0.044) vs 0.175 (SD 0.025); third quartile it is 0.326 (SD 0.051) vs 0.117 (SD 0.015); and fourth (most distal) quartile is 0.600 (SD 0.183) vs 0.319 (SD 0.082) respectively. Using ANOVA testing all differences were found to be significant to p<0.001. CONCLUSION: Torn plantar plates demonstrate increased vascular density throughout the length of the plantar plate with an increase in density most notable in the region at or just proximal to the attachment to the proximal phalanx. The clinical significance of the increased vascularity of torn plantar plates is unknown at this time. However, the increase in vasculature may suggest that the plantar plate is a structure that is attempting to heal.