The detection of pedal osteomyelitis in diabetic patients

Abstract

Pedal osteomyelitis in diabetic patients is a serious clinical problem. There is no single, reliable diagnostic tool; plain films are inaccurate, bone scans nonspecific and the role of human pooled immunoglobulin (Hig) scans remains unclear. Magnetic Resonance Imaging (MRI) may prove useful. We therefore aimed to compare these four diagnostic modalities. Thirteen diabetic patients with possible pedal osteomyelitis were recruited. Nine were found to have osteomyelitis based on clinical, microbiological, and surgical findings. All were scanned with all four modalities and the results compared. MRI scans correctly identified all positive cases, with two false positive cases, and excelled in localising infection, allowing for surgical planning. Plain film and Hig scans were less sensitive (6/9 and 7/9 cases, respectively), were difficult to interpret and were poor in localising infection. Bone scans identified eight of the nine cases, with no false positives. In conclusion, this small study suggests that plain films and Hig scans did not confer any additional benefit in the diagnosis ofpedal osteomyelitis. Bone scans are a useful screening tool, but when positive an MRI scan should be sought to confirm the diagnosis. Practical Diabetes lnt 1999; 16(4): 98-1 00 Mean age Mean duration of diabetes Number of patients with type 2 DM Number of patients with type2 DM on insulin Mean HbA,, 9.4% (6.9i13.8%) 59 yr (38-84 yr) 14 yr (1-39 yr) 6 6 1 Number of patients with type 1 DM

Expert opinion on the management of infections in the diabetic foot

“…The prevalence of standard defined osteomyelitis was 50% (range 32% to 89%), the pooled sensitivity was 77–100% and the specificity was 40–100%. In subjects with diabetes, the diagnostic odds ratio was 42 (CI 15–120), the summary positive likelihood ratio was 3.8 (CI 0.2.5–5.8) and the summary negative likelihood ratio was 0.14 (CI 0.08–0.26) . More recently performed studies reported lower diagnostic odds ratios (25, CI 6–117) compared with older ones, perhaps because their study designs were better.…”

“…On the basis of seven studies, Kapoor et al . found the performance characteristics of a triple‐phase bone scan were markedly inferior to MRI , with a diagnostic odds ratio of 3.5 (CI 1.0–13) versus 150 (CI 55–411), respectively . Healthy bone may also have an increased uptake of the radiopharmaceutical, especially in the forefoot .…”

High Risk Diabetic Foot

“…Dinh and coworkers (170) identified four trials, all of which had a prospective setup (180,182,195,199). Kapoor et al (198) found 16 trials in their meta-analysis (171,172,180,182,188,192,195,196,(200)(201)(202)(203)(204)(205)(206)(207). Only one study was conducted for less than 10 years (195).…”

“…Bone scans are usually performed with 99m Tc-methylene diphosphate. Seven studies were found by Kapoor et al (198) that compared MRI with triplephase bone scan (171,182,188,192,202,206,207). Capriotti et al found in a total of 719 lesions that three-phase bone scans were sensitive (90%) but not specific (46%) (208).…”