To determine whether there is any difference in infection rate
at 90 days between trauma operations performed in laminar flow and
plenum ventilation, and whether infection risk is altered following
the installation of laminar flow (LF). We assessed the impact of plenum ventilation (PV) and LF on the
rate of infection for patients undergoing orthopaedic trauma operations.
All NHS hospitals in England with a trauma theatre(s) were contacted
to identify the ventilation system which was used between April
2008 and March 2013 in the following categories: always LF, never
LF, installed LF during study period (subdivided: before, during
and after installation) and unknown. For each operation, age, gender,
comorbidity, socio-economic deprivation, number of previous trauma
operations and surgical site infection within 90 days (SSI90) were
extracted from England’s national hospital administrative Hospital
Episode Statistics database. Crude and adjusted odds ratios (OR)
were used to compare ventilation groups using hierarchical logistic
regression. Subanalysis was performed for hip hemiarthroplasties.Aims
Patients and Methods
Digital templating in hip replacement is commonly performed with radiological markers to determine the magnification. The latter can also be determined by measuring the distance from the x-ray focal spot to the object and the distance from the x-ray focal spot to the radiological cassette or image receptor. We used post-operative radiographs of total hip replacements and hemiarthroplasties from 22 patients to calculate the magnification using both methods. The accuracy of each method was ascertained by measuring the size of the head of the implant projected on to the radiographs and comparing the result with the known size recorded in the medical records. The accuracy was found to be similar with a mean absolute measurement error of 2.6% ( We conclude that the distance measuring method is as accurate as the radiological marker method, but may avoid some of the disadvantages such as misplacement of the marker or placement outside the radiological field. It may also be more acceptable to the patient and radiographer.
