Acute compartment syndrome (ACS) occurs after muscle injury and is characterised by increased pressure in the muscle compartment that can result in devastating complications if not diagnosed and treated appropriately. ACS is currently confirmed by repeated needle sticks to measure the compartment pressure using a hand-held compartment pressure monitor. This approach is often not reproducible and is not appropriate for continuous monitoring. To address the shortcomings of currently available technology we are developing an implantable micro-device that will measure compartment pressure directly and continuously over the 24 hours critical period following injury using a radio frequency identification (RFID) platform integrated with a MEMS capacitive pressure sensor. The prototype implantable device measuring 3mmx3mm consists of a capacitive pressure sensor, a sensor readout circuitry, an antenna and a radio frequency reader. A prototype sensor was packaged in Silicone gel (MED-6640, Nusil Technology LLC) for ex vivo and in vivo testing in three compartment models. First, it was tested ex vivo in an airtight vessel using a blood pressure monitor to pump air and increase the pressure inside the vessel. Second, it was implanted in a muscle compartment of a fresh porcine hind limb and an infusion pump with normal saline was used to raise the tissue pressure. Third, it was implanted in the posterior thigh muscle of a rat where the pressure was increased by applying a tourniquet around the thigh. The readings were compared with those from a hand-held Stryker Intra-compartmental Pressure Monitor System used in the trauma room.Significance
Methods
Fear avoidance (FA) has been identified as a risk factor for poor prognosis and a target for intervention in patients with low back pain (LBP), but the mechanisms involved need clarification. Experimental studies would benefit from the use of carefully developed and controlled stimuli representing avoided movements in back pain, and matched stimuli of movements to provide a credible control stimuli. Existing stimuli depicting avoided movements in LBP are static, do not include a set of control stimuli, and do not control for possible systematic observer biases. Two studies were carried out aiming to develop and test LBP patients' responses to videos of models depicting commonly avoided movements associated with back pain, and those associated with a control condition, wrist pain. Two samples of LBP patients rated how much pain and harm each movement would cause them. They also reported how often they avoided the movement. The findings from the first study (N = 99) indicate that using videos of commonly avoided movements in low back pain is viable, and that movements associated with wrist pain provide an acceptable control stimuli. Participants in the second study (N=85) consistently rated movements depicted by females as causing more harm, and more frequently avoided than the same movements depicted by males.Background
Method and results
Up to 70% of the differences in human bone mass have been attributed to genetic background. These differences are associated with alterations in the biomechanical properties, micro-architecture and remodeling of bone as well as its susceptibility to fracture and its capacity for repair. In previous work it was shown that C57Bl6 mice carrying one copy of the parathyroid hormone related protein (PTHrP+/−) gene developed osteopenia by four months of age. The current study was designed to determine if the haploinsufficient phenotype was maintained on a C3H background. PTHrP+/+ and PTHrP+/− mice on C57Bl6 and C3H backgrounds were euthanised between 6 and 18 months of age. The femurs were harvested, fixed in 4% paraformaldehyde overnight and scanned on a Skyscan 1172 equipped with a 10kV X-ray source and a 10 megapixel camera at a resolution 5μm. The amount and quality of cortical and trabecular bone was quantified from 2D images and 3D reconstructions using CTAn, CTvol and CTVox software. The undecalcified specimens were embedded at low temperature in MMA, sectioned at 5 μm and stained with Von Kossa and Toluidine Blue to distinguish mineralized from unmineralized tissue.Purpose
Method
Internal fixation of fractures in the presence of osteopenia has been associated with a failure rate as high as 25%. Enhancing bone formation and osseointegration of orthopaedic hardware is a priority when treating patients with impaired bone regenerative capacity. Fibroblast Growth Factor (FGF) 18 regulates skeletal development and could therefore have applications in implant integration. This study was designed to determine if FGF 18 promotes bone formation and osseointegration in the osteopenic FGFR3−/− mouse and to examine its effect on bone marrow derived mesenchymal stem cells (MSCs). In Vivo: Intramedullary implants were fabricated from 0.4 × 10mm nylon rods coated with 300nm of titanium by physical vapour deposition. Skeletally mature, age matched female FGFR3−/− and wild type mice received bilateral intramedullary femoral implants. Left femurs received an intramedullary injection of 0.1μg of FGF 18 (Merck Serono), and right femurs received saline only. Six weeks later, femurs were harvested, radiographed, scanned by micro CT, and processed for undecalcified for histology. In Vitro: MSCs were harvested from femurs and tibiae of skeletally mature age matched FGFR3−/− and wild type mice. Cells were cultured in Alpha Modified Eagles Medium (αMEM) to monitor proliferation or αMEM supplemented with ascorbic acid and sodium beta-glycerophosphate to monitor differentiation. Proliferation was assessed through cell counts and metabolic activity at days 3, 6 and 9. Differentiation was assessed through staining for osteoblasts and mineral deposition at days 6, 9 and 12.Purpose
Method
We have reviewed 21 cases of dorsal dislocation of carpometacarpal joints. In 15 of them the diagnosis was missed when they were first seen in an accident and emergency department. General swelling may obscure the characteristic clinical deformity and routine radiographs may not show the displacement clearly. It is recommended that a true lateral radiograph of the hand be requested when this injury is suspected.
