The Vancouver classification has been shown by its developers to be a valid and reliable method for categorising the configuration of periprosthetic proximal femoral fractures and for planning their management. We have re-validated this classification system independently using the radiographs of 30 patients with periprosthetic fractures. These were reviewed by six experienced consultant orthopaedic surgeons, six trainee surgeons and six medical students in order to assess intra- and interobserver reliability and reproducibility. Each observer read the radiographs on two separate occasions. The results were subjected to weighted kappa statistical analysis.

The respective kappa values for interobserver agreement were 0.72 and 0.74 for consultants, 0.68 and 0.70 for trainees on the first and second readings of the radiographs and 0.61 for medical students. The intra-observer agreement for the consultants was 0.64 and 0.67, for the trainees 0.61 and 0.64, and for the medical students 0.59 and 0.60 for the first and second readings, respectively. The validity of the classification was studied by comparing the pre-operative radiological findings within B subgroups with the operative findings. This revealed agreement for 77% of these type-B fractures, with a kappa value of 0.67.

Our data confirm the reliability and reproducibility of this classification system in a European setting and for inexperienced staff. This is a reliable system which can be used by non-experts, between centres and across continents.

The quantification of local bone blood flow in man has not previously been possible, despite its importance in the study of normal and pathological bone. We report the use of positron emission tomography, using 15O-labelled water, to measure bone blood flow in patients with closed unilateral fractures of the tibia. We compared fractured and unfractured limbs; alterations in blood flow paralleled those found in animal models. There was increased tibial blood flow at the fracture site as early as 24 hours after fracture, reaching up to 14 times that in the normal limb at two weeks. Blood flow increase was less in displaced than in undisplaced fractures. The muscle to bone ratios of blood flow were similar to those in previous animal work using other techniques. Positron emission tomography will allow study of human bone blood flow in vivo in a wide variety of pathological conditions.