Introduction:. Diabetic ulcer superficial swab cultures have a low specificity for guiding antibiotic treatment. Some studies have recently re-assessed and advocated the role of superficial swabs. We have performed an analysis of microbiology results in patients with infected diabetic ulcers to further appraise the need for using deep tissue cultures as a guide for antimicrobial treatment. Methods:. We reviewed 23 consecutive diabetic patients in 2013. All patients underwent investigation and treatment by the Orthopaedic department for deep, intractable diabetic ulceration. Microbiology culture results from superficial swabs were compared to deep tissue and bone biopsies. Results:. The mean numbers of isolates from soft tissue and bone biopsies were 2.1 and 1.8 respectively (range 1–4). The most prevalent organisms seen in deep samples were anaerobes (9 patients), Staphylococcus aureus (8 patients) and entrococci (4 patients). In superficial swabs, 74% cultured non-specific, mixed skin flora and enteric species. The remaining 6 patients cultured Staphylococcus aureus alone (1), with Steptococcus (2), Pseudomonas (2) and MRSA (1). All 23 soft tissue biopsies were culture positive, 19 bone biopsies were positive of which 14 grew the same organisms of soft tissue cultures. In deep tissue/ bone biopsies, 13/23 patients cultured specifically organisms that were seen non-specifically in superficial swab cultures. However, in 10 patients deep tissue specimens, grew organisms that were not cultured from superficial swabs with 6 of these being anaerobes. Conclusion:. We have shown that in 43% of cases, deep tissue cultures isolated organisms that were not grown by superficial swab cultures. In 26% of these cases the organism was an anaerobe favouring deep, low oxygen tension environments. We refute recent evidence claiming the value of superficial swabs. We implore physicians treating patients with these ulcers to refer to an Orthopaedic surgeon to perform deep tissue biopsies and treat according to their culture results

The treatment of peri-prosthetic joint infection (PJI) of the ankle is not standardised. It is not clear whether an algorithm developed for hip and knee PJI can be used in the management of PJI of the ankle. We evaluated the outcome, at two or more years post-operatively, in 34 patients with PJI of the ankle, identified from a cohort of 511 patients who had undergone total ankle replacement. Their median age was 62.1 years (53.3 to 68.2), and 20 patients were women. Infection was exogenous in 28 (82.4%) and haematogenous in six (17.6%); 19 (55.9%) were acute infections and 15 (44.1%) chronic. Staphylococci were the cause of 24 infections (70.6%). Surgery with retention of one or both components was undertaken in 21 patients (61.8%), both components were replaced in ten (29.4%), and arthrodesis was undertaken in three (8.8%). An infection-free outcome with satisfactory function of the ankle was obtained in 23 patients (67.6%). The best rate of cure followed the exchange of both components (9/10, 90%). In the 21 patients in whom one or both components were retained, four had a relapse of the same infecting organism and three had an infection with another organism. Hence the rate of cure was 66.7% (14 of 21). In these 21 patients, we compared the treatment given to an algorithm developed for the treatment of PJI of the knee and hip. In 17 (80.9%) patients, treatment was not according to the algorithm. Most (11 of 17) had only one criterion against retention of one or both components. In all, ten of 11 patients with severe soft-tissue compromise as a single criterion had a relapse-free survival. We propose that the treatment concept for PJI of the ankle requires adaptation of the grading of quality of the soft tissues.

Cite this article: Bone Joint J 2014;96-B:772–7.