The effect of goniometric alignment on passive ankle dorsiflexion range of motion among patients following ankle arthrodesis or arthroplasty.

UNLABELLED: Goniometric measurement is a standard method used to quantify limited ankle dorsiflexion (DF). However, compensatory motion at the subtalar and midtarsal joints might also contribute to the amount of ankle DF obtained by goniometric measurements. The purpose of this study was to examine the effect of goniometric alignment on DF range of motion measurement among patients following ankle arthrodesis or arthroplasty and age- and gender-matched controls. A total of 22 participants were recruited to participate in this observational cohort study, including 7 patients following total ankle arthroplasty (2 male, 5 female; mean age = 67.5 years, standard deviation [SD] = 9.6 years), 4 patients following ankle arthrodesis (2 male, 2 female; mean age = 70.5 years, SD = 5.2 years), and 11 age- and gender-matched controls (4 male, 7 female; mean age 67.5 years, SD = 9.0 years). Two investigators measured and recorded ankle DF passive range of motion (PROM) using a randomly determined sequence of 2 alignment methods: (1) the distal aspect of the lateral calcaneus, and (2) the fifth metatarsal. One-sample t tests were performed to assess differences in ankle DF between the 2 different alignment methods. Significantly greater degrees of DF were obtained when aligning with the fifth metatarsal versus the lateral calcaneus on the patients' uninvolved sides and the randomly selected side of matched controls (P < .05) but not on the patients' operative side (P > .05). This study found that more degrees of DF PROM are measured when aligning a goniometer with the fifth metatarsal versus the calcaneus on the uninvolved side of patients and matched controls. LEVELS OF EVIDENCE: Diagnostic, Level IV.

Regulation of lymphatic capillary regeneration by interstitial flow in skin.

Decreased interstitial flow (IF) in secondary lymphedema is coincident with poor physiological lymphatic regeneration. However, both the existence and direction of causality between IF and lymphangiogenesis remain unclear. This is primarily because the role of IF and its importance relative to the action of the prolymphangiogenic growth factor vascular endothelial growth factor (VEGF)-C (which signals primarily through its receptor VEGFR-3) are poorly understood. To clarify this, we explored the cooperative roles of VEGFR-3 and IF in a mouse model of lymphangiogenesis in regenerating skin. Specifically, a region of lymphangiogenesis was created by substituting a portion of mouse tail skin with a collagen gel within which lymphatic capillaries completely regenerate over a period of 60 days. The relative importance of IF and VEGF-C signaling were evaluated by either inhibiting VEGFR-3 signaling with antagonistic antibodies or by reducing IF. In some cases, VEGF-C signaling was then increased with exogenous protein. To clarify the role of IF, the distribution of endogenous matrix metalloproteinases (MMPs) and VEGF-C within the regenerating region was determined. It was found that inhibition of either VEGFR-3 or IF suppressed endogenous lymphangiogenesis. Reduction of IF was found to decrease lymphatic migration and transport of endogenous MMP and VEGF-C through the regenerating region. Therapeutic VEGF-C administration restored lymphangiogenesis following inhibition of VEGFR-3 but did not increase lymphangiogenesis following inhibition of IF. These results identify IF as an important regulator of the pro-lymphangiogenic action of VEGF-C.