We examined the use of oxygen radical scavengers in preventing the no-reflow phenomenon and improving bone-muscle cell survival in an ischemic extremity replant model. A total of 70 Lewis rat modified hindlimb replants were performed after specific periods of cold ischemia and intraarterial perfusion with either superoxide dismutase and catalase, specific oxygen free-radical scavengers, or a control solution. Ischemic hindlimbs treated with superoxide dismutase and catalase showed a statistically significant (p less than 0.05) improvement in vascular patency after prolonged cold ischemia when compared to controls. Histologically, experimental extremities demonstrated greater osteoblast, osteocyte, and muscle cell survival in replanted hindlimbs with patent vascular anastomoses. The perfusion of severed limbs and digits and free vascularized tissue transfers with superoxide dismutase and catalase after a period of ischemia has already occurred may prolong the ischemic "time window" tolerated for successful tissue survival.