Pharmacokinetic modeling of multislice dynamic contrast-enhanced MRI in normal-healing radial fractures: A pilot study.

PURPOSE: To define the range of quantitative pharmacokinetic parameters in normal-healing bone with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). DCE-MRI is an established technique for characterizing abnormal tissue microvasculature within solid tumors, but has also shown promise for assessing bone and bone marrow. MATERIALS AND METHODS: In this study ethical approval for eight patients was obtained. Inclusion criteria were an extra-articular distal radial fracture in patients aged 20-50 years which had united by 6 weeks in plaster cast. This was assessed by an experienced orthopedic surgeon. DCE-MRI was performed at 1.5T 6 weeks after initial injury. The transfer constant (K(trans) ), transfer rate (Kep ), and initial area under the curve (IAUC) values for the fracture site and adjacent marrow were obtained for each patient. RESULTS: The mean T1 , K(trans) , Kep , and IAUC at the fracture site were 1713 (standard deviation [SD] 645), 0.09 (SD 0.07), 0.17 (SD 0.17) and 4.9 (SD 4.4). The relative standard deviation (RSD) for the fracture site ranged from 0.38 to 0.97 and for the adjacent marrow ranged from 0.95-3.88. Within each patient the range of RSDs was 0.04-0.42 for T1 , 0.26-0.91 for K(trans) , 0.14-1.06 for Kep , and 0.35-0.96 for the IAUC. CONCLUSION: Pharmacokinetic measures of perfusion can be obtained from healing fractures using DCE-MRI with "excellent" intraclass correlation coefficients for inter- and intrarater reliability. The use of these perfusion parameters is limited by wide patient-to-patient variation and slice-to-slice variation within patients.

Open reduction and fixation of displaced lateral clavicle fractures using the Minimally Invasive Acromioclavicular Joint Reconstruction (MINAR®) technique: a case series review.

BACKGROUND: Lateral end of clavicle fractures can be a challenge, with a 20% to 30% non-union rate if treated non-operatively. Several operative options exist, each having their own merits and some having potential disadvantages. The Minimally Invasive Acromioclavicular Joint Reconstruction (MINAR®) (Storz, Tutlingen, Germany) set uses an Orthocord (Depuy Synthes Mitek, Leeds, UK) suture and two Flip Tacks (Storz) via a transclavicular-coracoid approach to reconstruct the coracoclavicular ligaments. METHODS: Referrals were made to two senior surgeons at separate institutions regarding Robinson Type 3 fractures of the lateral end of the clavicle. All patients were treated with MINAR implant via a minimally invasive approach. Two-year follow-up was obtained using the Oxford Shoulder Score (OSS) and the Quick DASH (Disability of the Arm Shoulder and Hand) score. RESULTS: Sixteen cases of acute fractures of the lateral end of the clavicle were included in this series. At final follow-up, the mean OSS was 44.75 (range 35 to 48) and the median Quick DASH score was 2.3 (range 0 to 35.9). Fifteen patients achieved bony union (one asymptomatic non-union) and there were no complications or re-operations. CONCLUSIONS: The MINAR is reproducible and safe when treating lateral end of clavicle fractures. We consider that, over the short- to mid-term, it achieves results equivalent to those for other implants.

Metal ion levels decrease after revision for metallosis arising from large-diameter metal-on-metal hip arthroplasty.

Concerns have been renewed regarding the possible long-term effects of elevated circulating levels of cobalt and chromium as a direct result of implantation of large femoral head diameter metal-on-metal bearings. In order to establish whether metal ion levels remain persistently elevated, we compared metal ion levels before and after revision surgery in patients with large head diameter (greater than 38 mm) metal-on-metal total hip arthroplasty or hip resurfacing arthroplasty. At greater than one year post removal of a large-diameter metal-on-metal hip implant for the indication of symptomatic metallosis, metal ion levels were found to fall to almost normal levels.

Synthesis of N1-phenethyl substituted indole derivatives as new melatoninergic agonists and antagonists.

The potency of new indolic N1-phenethyl substituted melatoninergic ligands with and without methyl groups in the alpha and beta position of the alkanamidoethyl side chain was examined using the pigment aggregation response in a clonal line of Xenopus laevis melanophores. The non 5-OMe substituted compounds, 8a--e, are all weak antagonists while introduction of the 5-OMe group, 9a--e, increases both agonist and antagonist activity except for 9c (R=C3H7), which is only an agonist and 9e (R=c-C4H7), which is only an antagonist. Introduction of an alpha-methyl group into the 5-OMe derivatives, 14a-e, reduces the agonist potency while introduction of a beta-methyl group has only a small effect on either the agonist or antagonist potency. Double beta-methyl substitution of the 5-OMe derivatives, 20a--e, generally increases the agonist potential (20c, R=C3H7 is the most potent agonist of the compounds described) and decreases the antagonist potency, except for 20a (R=CH3), which is the most potent antagonist of this series of compounds.