Diabetes mellitus is recognised as a risk factor for carpal tunnel syndrome. The response to treatment is unclear, and may be poorer than in non-diabetic patients. Previous randomised studies of interventions for carpal tunnel syndrome have specifically excluded diabetic patients. The aim of this study was to investigate the epidemiology of carpal tunnel syndrome in diabetic patients, and compare the outcome of carpal tunnel decompression with non-diabetic patients. The primary endpoint was improvement in the QuickDASH score. The prevalence of diabetes mellitus was 11.3% (176 of 1564). Diabetic patients were more likely to have severe neurophysiological findings at presentation. Patients with diabetes had poorer QuickDASH scores at one year post-operatively (p = 0.028), although the mean difference was lower than the minimal clinically important difference for this score. After controlling for underlying differences in age and gender, there was no difference between groups in the magnitude of improvement after decompression (p = 0.481). Patients with diabetes mellitus can therefore be expected to enjoy a similar improvement in function.

A suspected fracture of the scaphoid remains difficult to manage despite advances in knowledge and imaging methods. Immobilisation and restriction of activities in a young and active patient must be balanced against the risks of nonunion associated with an undiagnosed and undertreated fracture of the scaphoid.

The assessment of diagnostic tests for a suspected fracture of the scaphoid must take into account two important factors. First, the prevalence of true fractures among suspected fractures is low, which greatly reduces the probability that a positive test will correspond with a true fracture, as false positives are nearly as common as true positives. This situation is accounted for by Bayesian statistics. Secondly, there is no agreed reference standard for a true fracture, which necessitates the need for an alternative method of calculating diagnostic performance characteristics, based upon a statistical method which identifies clinical factors tending to associate (latent classes) in patients with a high probability of fracture.

The most successful diagnostic test to date is MRI, but in low-prevalence situations the positive predictive value of MRI is only 88%, and new data have documented the potential for false positive scans. The best strategy for improving the diagnosis of true fractures among suspected fractures of the scaphoid may well be to develop a clinical prediction rule incorporating a set of demographic and clinical factors which together increase the pre-test probability of a fracture of the scaphoid, in addition to developing increasingly sophisticated radiological tests.