The effects of pressurization on fracture swelling and joint stiffness in the rabbit hind limb.

Long bone fractures frequently cause limb swelling and joint stiffness, and the two effects are generally assumed to be related, an assumption long held but rarely tested. The authors investigated limb swelling and joint stiffness in rabbits with experimental 28-day healing fractures. Eleven control rabbits were treated with bilateral hind limb skeletal fixation and unilateral distal tibia fractures. Subsequent limb swelling occurred bilaterally, but it was significantly greater on the side fractured. All fractures healed. Ankles in both fractured and unfractured limbs became significantly stiffer, compared with preinjury values, but ankles in the fractured limbs became significantly stiffer than those in the unfractured control limbs. Air pressure of 10 mmHg above atmospheric pressure was applied for four days to newly fractured limbs in 11 additional rabbits. Pressurization reduced swelling but did not significantly affect ankle stiffness. In general, reduction in postfracture swelling by application of external pressure did not significantly affect adjacent joint stiffness.