Effect of Unweighting the Hind Limbs of Rats on Joint Contractures

[Purpose] The purpose of this study was to clarify the effects of unweighting the lower limbs on joint contractures. [Subjects] The subjects of this study were ten Wistar rats. [Methods] The rats were divided into one control (C) and three experimental groups. The right ankle joints of the first experimental group were fixed in full plantar flexion (F). The second experimental group’s hind limbs were unweighted by suspension (S). The third experimental group’s hind limbs were suspended and the right ankle joints were fixed in full plantar flexion (FS). The period of this study was one week. On the first and last days of this study, all of the rats’ angles of ankle dorsiflexion were measured. [Results] On the last day, the angles of dorsiflexion of the F and FS groups were significantly smaller than those of the C and S groups. The decreased angles of dorsiflexion of the FS group were significantly smaller than those of the F group. [Conclusion] Our results indicate that unweighting the hind limbs causes severe joint contractures in rats.