The epidemiology of reoperations for orthopaedic trauma.

INTRODUCTION: The Royal College of Surgeons of England (RCS) has issued guidance regarding the use of reoperation rates in the revalidation of UK-based orthopaedic surgeons. Currently, little has been published concerning acceptable rates of reoperation following primary surgical management of orthopaedic trauma, particularly with reference to revalidation. METHODS: A retrospective review was conducted of patients undergoing clearly defined reoperations following primary surgical management of trauma between 1 January 2010 and 31 December 2011. A full case note review was undertaken to establish the demographics, clinical course and context of reoperation. A review of the imaging was performed to establish whether the procedure performed was in line with accepted trauma practice and whether the technical execution was acceptable. RESULTS: A total of 3,688 patients underwent primary procedures within the time period studied while 70 (1.90%, 99% CI: 1.39-2.55) required an unplanned reoperation. Thirty-nine (56%) of these patients were male. The mean age of patients was 56 years (range: 18-98 years) and there was a median time to reoperation of 50 days (IQR: 13-154 days). Potentially avoidable reoperations occurred in 41 patients (58.6%, 99% CI: 43.2-72.6). This was largely due to technical errors (40 patients, 57.1%, 99% CI: 41.8-71.3), representing 1.11% (99% CI: 0.73-1.64) of the total trauma workload. Within RCS guidelines, 28-day reoperation rates for hip, wrist and ankle fractures were 1.4% (99% CI: 0.5-3.3), 3.5% (99% CI: 0.8%-12.1) and 1.86% (99% CI: 0.4-6.6) respectively. CONCLUSIONS: We present novel work that has established baseline reoperation rates for index procedures required for revalidation of orthopaedic surgeons.

Higher-order multiple scattering theories for charged particle transport.

The Fermi pencil beam formula and the higher-order multiple scattering theory due to Jette are shown to result from a perturbative treatment of the linear Boltzmann equation with Fokker-Planck scattering. Using asymptotic one-dimensional solutions for the transverse integrated (spherical) fluence as well as its variance, approximate higher-order pencil beam theories are constructed. These simple and explicit formulae are shown, by comparison with benchmark Monte Carlo results, to be significantly more accurate than the Fermi and Jette equations, particularly at large distances from the beam axis.