Introduction: Deep postoperative infection in patients who have had surgery for fractured neck of femurs (NOF) has high morbidity and mortality. There is a reported incidence of 0.6–1.1% despite perioperative antibiotic prophylaxis (Co-Amoxiclav in our institution). The commonest causative organism reported is Staphylococcus aureus.
Method: We designed a retrospective study over a 6 month period in 2008. All patients having surgery for NOF were reviewed for positive bacterial growth on post-operative wound swabs.
Results: 143 patients had surgery and were included in our study. The mean ASA grade was 3. Over 90% of wounds were closed with clips. The average stay in hospital was 36 days. Mortality from postoperative infection was 1.41%., with 5 patients readmitted for treatment post discharge. Only 17 patients (11.9%) had positive wound swabs, and of these, 6 were asymptomatic and clinically well, 6 developed deep infections of the hip (4.23%), and 5 had superficial wound infections (3.53%). Signs of infection began on average 12 days post-operatively, with a delay of 4.5 days before starting treatment. Discharge from the wound was the most common sign (89%), followed by erythema (65%), and pyrexia (36.4%). The average white cell count (WCC) was normal (10.2 x 109 cells/L), but C-Reactive Protein was found to be raised. Antibiotics were given for an average of 34 days. All deep infections had surgical washouts after an average 4.6 days post diagnosis. Two patients who developed infection required a girdlestone operation (one died). The main bacteria isolated in 65% of cases were coliforms, pseudomonas and enterococci. Only one patient grew Staphylococcus aureus. All cultures were sensitive to ciprofloxacin and Tazocin, however, penicillin and benzyl-penicillin were started empirically in all cases according to local hospital policy.
Conclusion: Deep postoperative infection following a NOF repair is common and associated with mortality and morbidity. ASA grades were higher in such patients. WCC is not a reliable indicator in the early stages. Staphylococcus aureus was not found to be the predominant bacteria causing infection, although this may be due to penicillin prophylaxis. We have changed our empirical antibiotics for hip wound infections.
