Several orthopaedic operations are encumbered with a high risk of infection. Early detection of such complication is of utmost importance for achieving good results.

From 1990 to 1998 a prospective study was done in 104 orthopaedic patients, who had a higher risk for postoperative infections. Diagnoses had been chronic osteomyelitis (47 cases), bone transplantation after osteomyelitis (19 cases), malignant bone tumors receiving chemotherapy (16 cases) and revision alloarthroplasty (22 cases). Consecutive levels of leucocytes in the wound drainages (deep and subcutaneus), white blood cell count (WBC) and c-reactive proteine (CRP) were analyzed.

Seventeen patients (septic group) were reoperated for suspected infection. The culture discount revealed Staphylococcus aureus (7 cases), Staphylococcus epidermidis (5 cases), Streptococcus hemoliticus (1 case), Mycobacterium tuberculosis (1 case), Enterococcus fae-calis (1 case), mixed organisms (2 cases), and histological signs of infection (4 cases). Comparing the aseptic and septic group no difference was noted for WBC < 2 days (p = 0.39), 2–3 days (p = 0.18), 3–6 days (p = 0.44) and > 6 days (p = 0.46). CRP difference was noted on the fourth day: mean 7.6 +− 0.8 mg/dl (range 6.0 to 9) (septic group); mean 5.9 +− 1.2 mg/dl (range 3.2 to 8.4) (aseptic group) (p < 0.001). The deep drainage leucocytes demonstrated to 12 hours: mean 5636 +− 2134 (range 2400 to 11200) (septic group) and mean 8531 +− 3312 (range 3100 to 18200) (aseptic group) (p < 0.001). 36 to 48 hours: the values changed adversely. 48 to 72 hours: mean 9146 +− 3666 (range 4700 to 16200) (septic group) and mean 2393 +− 879 (range 1100 to 4100) (aseptic group) (p < 0.001). The subcutaneus drainage leucoytes were 1.5 to 1.9 times higher (aseptic group) and 0.13 to 1.03 times lower (septic group) compared to the deep drainage.

We recommend deep drainage leucocytes monitoring 48 to 72 hours after the operation. Values greater 4100 (upper range of aseptic control) are suspicious and over 9146 (mean value of septic group) are strongly associated with an underlying wound infection.