In a randomized, prospective double blind trial evaluating antibiotic prophylaxis for internal fixation of proximal femur fractures, the prognostic value of preoperative risk parameters, namely triceps skinfold, upper arm circumference, dynamometry, serum albumin, transferrin, prealbumin, lymphocyte count and serum zinc was analyzed. A population at risk of postoperative infection could be defined with serum albumin value and lymphocyte count: a serum albumin of less than 40 g/l correlated with increased local complications and a lymphocyte count under 1400 microliters coincided with increase in systemic infections. No correlation between perioperative transfusion and postoperative infections was found.