The aim of the Scaphoid Magnetic Resonance Imaging in Trauma (SMaRT) trial was to evaluate the clinical and cost implications of using immediate MRI in the acute management of patients with a suspected fracture of the scaphoid with negative radiographs. Patients who presented to the emergency department (ED) with a suspected fracture of the scaphoid and negative radiographs were randomized to a control group, who did not undergo further imaging in the ED, or an intervention group, who had an MRI of the wrist as an additional test during the initial ED attendance. Most participants were male (52% control, 61% intervention), with a mean age of 36.2 years (18 to 73) in the control group and 38.2 years (20 to 71) in the intervention group. The primary outcome was total cost impact at three months post-recruitment. Secondary outcomes included total costs at six months, the assessment of clinical findings, diagnostic accuracy, and the participants’ self-reported level of satisfaction. Differences in cost were estimated using generalized linear models with gamma errors.Aims
Patients and Methods
We describe the histology of a specimen taken from an amputated leg seven months after a 15 cm bone gap in the tibia had been closed by bone transport. Lengthening appeared to have occurred by repeated minor trauma to the bone, with the fractured trabeculae in sufficiently close contact for the repair process to proceed. Osteogenesis did not occur through a cartilage phase, but the fracture gaps were bridged by collagen fibres, around which new bone formed. Microfractures had repaired by primary healing with woven bone and with no microcallus. Small regions of bone were necrotic. Resorption of the necrotic bone and remodelling of the immature bundle and woven bone were still at an early stage, suggesting that complete remodelling in man may take years rather than months.
The incidence of refracture following the removal of screws and plates from the diaphyses of 115 forearm bones in 80 patients has been studied. Refracture occurred in four adult patients as a result of minimal trauma, in two patients at the original fracture site after premature plate removal, at the site of a countersunk interfragmentary screw in one and at the original fracture site in another who had required three operative procedures to achieve 'union'. It is suggested that refracture could have been avoided in at least two of these patients. If the 3.5 mm plating system has been used, the incidence of refracture should be minimal.
Bone weakness leading to refracture is a recognised complication of the removal of rigid fixation plates. We have used partially demineralised rabbit tibiae to simulate atrophic changes and to determine whether weakness is due to atrophy or to residual screw holes. Partial demineralisation and a screw hole each reduced maximum bending moment. However, energy absorbing capacity was little affected by demineralisation, but was reduced to 50% by a single drill hole. Residual screw holes are a considerably more important cause of bone weakness after plate removal than is cortical atrophy.
We used single-photon absorptiometry to assess the forearm bones after the removal of internal fixation plates in 14 patients. We found convincing evidence of cortical atrophy in only one patient, in whom the plates had been removed prematurely after only 16 months. It is suggested that such plates should be retained for at least 21 months, to allow bone density to return to its prefracture level. The recommendations of the AO/ASIF group are supported.
We compared, under laboratory conditions, the resistance to cutting out of the AO dynamic hip screw and the Pugh sliding nail. The mean load at cut out, adjusted for bone strength, was 70% greater for the Pugh sliding nail. The reasons for this difference are discussed.
