Predictors of Malreduction in Zone II and III Fifth Metatarsal Fractures Fixed With an Intramedullary Screw

BACKGROUND

Proper implant selection and placement is crucial during fixation of zone II and III fifth metatarsal fractures to avoid postoperative complications. This study examined the effects of screw parameters and placement on malreduction, delayed union, nonunion, and refracture rate.

METHODS

A retrospective review of zone II and proximal zone III fifth metatarsal fractures managed with intramedullary screw fixation was conducted. Comparisons were made between cortex distraction (gap) and ratios of screw length, diameter, and entry point. Further analysis was carried out between time to union and distraction in the lateral and plantar cortices.

RESULTS

The plantar and lateral gaps were both associated with the mean entry point ratio on the lateral and anteroposterior (AP) views (P < .001 for both views). No association between the plantar and lateral gaps and the screw diameter ratio (P = .393 for AP and P = .981 for lateral) or the screw length ratio (P = .966 for AP and P = .740 for lateral) was identified. The ratio of postoperative to preoperative apex height on AP and lateral views was correlated with the presence of lateral and plantar fracture gaps (P < .001). The presence of a plantar gap was associated with increased time to union (P = .022). A majority of fractures showed radiographic union at 12 weeks (38/43). Only 5 of 38 patients had delayed union. There were no refractures or nonunions as per available records.

CONCLUSION

Plantar or lateral fracture site distraction (gap) was not influenced by screw diameter ratio or screw length ratio. The entry point ratio had a significant effect on plantar and lateral gaps on postoperative radiographs, with lateral and inferior placement leading to fracture site distraction. Patients with a plantar gap did have an increased risk of delayed union. The results of this study emphasize the significance of the entry point when managing zone II and III fifth metatarsal base fractures.

LEVEL OF EVIDENCE

Level IV, case series.

Do teenage magazines give a genuine view of tooth colour?

OBJECTIVES

To compare the colour of incisors depicted in teenage magazines with a sample of Welsh teenagers.

MATERIALS AND METHODS

A representative one month sample of magazines aimed at 9- to 16-year-old girls was obtained from a retail outlet. All images containing photographs of anterior teeth were identified and the colour of the incisor teeth measured using two commercial shade guides. An additional category of 'whiter than shade guide' was introduced. Images were viewed under standardised conditions by the same examiner; 10% were repeated. Clinical measurements under standard conditions were taken, by the same examiner, of 9- to 16-year-old children presenting to the department over a one month period, using the same shade guides; 47% of readings were repeated. Data were entered into SPSS and comparison of proportions used to compare the two groups.

RESULTS

Nineteen magazines containing 268 images and 53 patients were used. Intra-examiner agreement with the two shade guides was 80% or 92% for patients and 93% or 96% for images. 0/53 (0%) clinical compared with 202/268 (75.4%) photographs were found to be whiter than the shade guide.

CONCLUSIONS

Teenage magazines do not give an accurate representation of the colour of teenager's teeth. The impact of this on children's self esteem is unknown.

1-370 GHz EPR linewidths for K3CrO8: a comprehensive test for the Anderson-Weiss model

Electron paramagnetic resonance (EPR) measurements have been carried out over the frequency range of 1-370 GHz on single crystals of potassium peroxychromate (K3CrO8) with the view of examining the current models of exchange narrowing of EPR signals in solids. K3CrO8 has a simple (tetragonal) lattice structure, can be grown as single crystals pure or diluted with an isostructural diamagnetic host K3NbO8, and its paramagnetism can be described by a very simple (S = 12, I = 0) spin Hamiltonian. The measurements were made at various orientations of single crystals in the Zeeman field, with emphasis on the principal directions of the g-tensor. For essentially all orientations, the linewidth decreases monotonically for measurements at resonance frequencies, omega0, from 1 to about 100 GHz, and then starts to increase at higher omega0. In order to delineate the spin exchange effects from other sources of line broadening, the measurements were repeated with a diluted spin system, K3NbO8 containing approximately/= 0.5 mole % of K3CrO8, representing the broadening effect of all the magnetic field dependent terms, such as the broadening due to the g-strain and sample holder/waveguide magnetization at the high field utilized, up to 14 T. Using these data, the K3CrO8 linewidths were analyzed in terms of the current models of spin exchange narrowing in three-dimensional systems. A reasonably good agreement was found with the Anderson-Weiss model, when modified for various line broadening effects. The accuracy of the analysis procedure was confirmed by the comparison of the presently determined values of the exchange constant, J, and the dipolar field, Hp, with their values obtained by dc magnetic susceptibility measurements and theoretical analysis, respectively; the agreement was within 5% for J (=1.35 K) and about 25% for Hp (160 G). However, some deviations and unusual splittings were noted in measurements at 370 GHz, whose origin remains unclear.