Femoral fracture, unilateral and bilateral, impaired the healing of dorsal skin incisions and formation of reparative granulation tissue in subcutaneously implanted polyvinyl alcohol sponges judged histologically and by breaking strengths and hydroxyproline contents, respectively, 1 week after injury in pair-fed rats kept at 22 degrees C. When rats were transferred to a room at 30 degrees C immediately after skin incision and sponge implants, with or without unilateral fracture, no differences in healing were observed between the two groups. Rats with skin incision, sponge implants, and either femoral fracture or sham-fracture excreted more urinary nitrogen than preoperatively when kept at 22 degrees. Counterpart groups transferred to a 30 degrees room right after operation excreted less urinary nitrogen than preoperatively, but because of lower food intakes postoperatively, the ratio of urinary nitrogen to food intake nitrogen was increased. With equivalent food intakes, pair-fed rats with fracture kept at 22 degrees postoperatively lost more weight and excreted more nitrogen than corresponding rats transfered to a 30 degrees room.