Biomechanical analysis of a novel Y-plate designed for the treatment of extraarticular distal humerus fractures

Adult distal humerus fractures are infrequent, yet they account for one-third of all humerus fractures. For the treatment of comminuted and osteoporotic fractures, locking plates are claimed to be biomechanically superior to alternative internal fixing techniques. Treatment remains difficult despite recent advancements and the use of locking plates due to frequent comminution, low bone quality, and limited healing ability in osteoporotic bone. An optimal design of the newly constructed plate and the control model were selected. The biomechanical characteristics of non-osteoporotic and osteoporotic synthetic bone were compared on six models. The biomechanical properties of the new plate were tested and compared on 54 osteoporotic synthetic humerus models. The control models were reconstructive and parallel LCPs. The tests were carried out under static and dynamic axial, lateral and bending loads. Fracture displacements were measured by optical measuring system Aramis. The test model is significantly stiffer for lateral load (p = 0.0007) and for bending load at the moment of model failure (p = 0.0002), while for axial load the LCP model showed greater stiffness (p = 0.0017). During lateral dynamic loading, all three LCP models broke and there was a significant difference compared to the test model (p = 0.0125). The LCP model is dynamically significantly more durable under axial load, while the largest displacements were recorded with the test model (p = 0.029). The displacements induced by all three loads are within the limits that fulfil the parameters of appropriate biomechanical stability. A novel locking plate for extra-articular distal humerus fractures may provide an alternative to the traditional two-plate.     

Immunization with BLS-Stx2B chimera totally protects dams from early pregnancy loss induced by Shiga toxin type 2 (Stx2) and confers anti-Stx2 immunity to the offspring

Shiga toxin producing Escherichia coli (STEC) are bacterial pathogens involved in food-borne diseases. Shiga toxin (Stx) is the main virulence factor of STEC and is responsible for systemic complications including Hemolytic Uremic Syndrome (HUS). It has been previously demonstrated that Shiga toxin type 2 (Stx2) induces pregnancy loss in rats in early stage of pregnancy. The main purpose of this study was to determine if an active immunization prevents Stx2 mediated pregnancy loss and confers passive protective immunity to the offspring. For that purpose Sprague Dawley female rats were immunized with the chimera based on the enzyme lumazine synthase from Brucella spp. (BLS) and the B subunit of Shiga toxin 2 (Stx2B) named BLS-Stx2B. After immunization females were mated with males. At day 8 of gestation, dams were challenged intraperitoneally with a sublethal and abortifacient dose of Stx2. The immunization induced high anti-Stx2B-specific antibody titers in sera and most important, prevented pregnancy loss. Pups born and breastfeed by immunized dams had high anti-Stx2B-specific antibody titers in sera. Cross-fostering experiments indicated that passive protective immunity against Stx2 was transmitted through lactation. These results indicate that immunization of adult female rats with BLS-Stx2B prevents Stx2-induced pregnancy loss and confers anti Stx2 protective immunity to the offspring.     

Subchondroplasty of the Foot: Two Case Reports

Early avascular necrosis of metatarsal heads and cuboid injuries are uncommon conditions encountered by foot and ankle specialists. Treatment options are limited and typically include long periods of offloading or non-weightbearing. There is limited published information on alternative treatment approaches for such pathologies when conservative therapies fail. Presented are 2 patient cases treated with a percutaneous calcium phosphate injection after failure of standard therapy, persistent pain, and bone marrow edema in the foot.     

Are We Misdiagnosing Diabetic Foot Osteomyelitis? Is the Gold Standard Gold?

To compare the incidence of osteomyelitis based on different operational definitions using the gold standard of bone biopsy, we prospectively enrolled 35 consecutive patients who met the criteria of ≥21 years of age and a moderate or severe infection based on the Infectious Diseases Society of America classification. Bone samples were obtained from all patients by percutaneous bone biopsy or intraoperative culture if the patient required surgery. Bone samples were analyzed for conventional culture, histology, and 16S ribosomal RNA genetic sequencing. We evaluated 5 definitions for osteomyelitis: 1) traditional culture, 2) histology, 3) genetic sequencing, 4) traditional culture and histology, and 5) genetic sequencing and histology. There was variability in the incidence of osteomyelitis based on the diagnostic criteria. Traditional cultures identified more cases of osteomyelitis than histology (68.6% versus 45.7%, p = .06, odds ratio [OR] 2.59, 95% confidence interval [CI] 0.98 to 6.87), but the difference was not significant. In every case that histology reported osteomyelitis, bone culture was positive using traditional culture or genetic sequencing. The 16S ribosomal RNA testing identified significantly more cases of osteomyelitis compared with histology (82.9% versus 45.7%, p = .002, OR 5.74, 95% CI 1.91 to 17.28) and compared with traditional cultures but not significantly (82.9% versus 68.6%, p = .17, OR 2.22, 95% CI 0.71 to 6.87). When both histology and traditional culture (68.6%) or histology and genetic sequencing cultures (82.9%) were used to define osteomyelitis, the incidence of osteomyelitis did not change. There is variability in the incidence of osteomyelitis based on how the gold standard of bone biopsy is defined in diabetic foot infections.