External fixation compared to intramedullary nailing of tibial fractures in the rat

Background and purpose It is not known whether there is a difference in bone healing after external fixation and after intramedullary nailing. We therefore compared fracture healing in rats after these two procedures

Differences in External and Internal Cortical Strain with Prosthesis in the Femur

The contact between a femoral stem prosthesis and the internal surface of the cortical bone with the stress in the interface is of crucial importance with respect to loosening. However, there are no reports of strain patterns at this site, and the main aim of the current study was to investigate differences of internal and external cortical strain in the proximal femur after insertion of a stem prosthesis. The external cortical strain of a human cadaveric femur was measured with strain gauges before and after implantation of a stem prosthesis. By use of optical fibres embedded longitudinally in the endosteal cortex, deformations at the implant–internal cortex interface could also be measured. The main external deformation during loading of the intact femur occurred as compression of the medial cortex; both at the proximal and distal levels. The direction of the principal strain on the medial and lateral aspects was close to the longitudinal axis of the bone. After resection of the femoral neck and insertion of a stem prosthesis, the changes in external strain values were greatest medially at the proximal level, where the magnitude of deformation in compression was reduced to about half the values measured on the intact specimen. Otherwise, there were rather small changes in external principal strain. However, by comparing vertical strain in the external and internal cortex of the proximal femur, there were great differences in values and patterns at all positions. The transcortical differences in strain varied from compression on one side to distraction on the other and vice versa in some of the positions with a correlation coefficient of 0.07. Our results show that differences exist between the external and internal cortical strain when loading a stem prosthesis. Hence, strain at the internal cortex does not correspond and can not be deducted from measured strain at the external cortex

Changes in serum cytokines in response to musculoskeletal surgical trauma

BACKGROUND: Trauma induces local and subsequent systemic inflammatory reactions, and when the cytokine production is deregulated, a systemic inflammatory response syndrome with a potentially lethal outcome can occur. The understanding of the physiological mechanism of the cytokine network would be useful to better comprehend pathological conditions. METHODS: We analysed a panel of 30 cytokines in the serum of 20 patients operated with total hip replacement. Cytokine release was assessed postoperatively up to 6 days by a multiplex antibody bead kit and compared to pre-operative values. RESULTS: Surgery induced significant increments in serum levels of IL-2R at 6 days after surgery, in levels of IL-6 at 6 hours after surgery and at 1 day after surgery, in levels of IL-8 at 6 hours after surgery, in levels of IL-16 at 6 hours and at 1 day after surgery. Significant decreases in serum levels of IL-1Rα were found at the end of surgery, in levels of IL-12 at the end of surgery and at 6 hours after, and in levels of Eotaxin during all phases of the postoperative course. CONCLUSIONS: The major findings were significant increases in systemic levels of the pro-inflammatory cytokines IL-6, IL-8, IL-16, while IL-12 was significantly decreased. Otherwise there were modest changes in the systemic cytokine kinetics and no significant expression of anti-inflammatory cytokines

Treatment outcome of chronic low back pain and radiographic lumbar disc degeneration are associated with inflammatory and matrix degrading gene variants: a prospective genetic association study

Background Inflammatory and matrix degrading gene variants have been reported to be associated with disc degeneration. Some of these variants also modulate peripheral pain. This study examines the association of these genetic variants with radiographic lumbar disc degeneration and changes in pain and disability at long-term after surgical and cognitive behavioural management. Methods 93 unrelated patients with chronic low back pain (CLBP) for duration of >1 year and lumbar disc degeneration were treated with lumbar fusion or cognitive intervention and exercises. Standardised questionnaires included the Oswestry Disability Index (ODI) and Visual Analog Score (VAS) for CLBP, were filled in by patients both at baseline and at 9 years follow-up. Degenerative changes at baseline Magnetic Resonance Imaging and Computed Tomography scans, were graded as moderate and severe (N=79). Yield and quality of blood and saliva DNA was assessed by nano drop spectrophotometry. Eight SNPs in 5 inflammatory and matrix degrading genes were successfully genotyped. Single marker and haplotype association with severity of degeneration, number of discs involved, changes in ODI and VAS CLBP, was done using Haploview, linear regression and R-package Haplostats. Results Association analysis of individual SNPs revealed association of IL18RAP polymorphism rs1420100 with severe degeneration (p = 0.05) and more than one degenerated disc (p = 0.02). From the same gene two SNPs, rs917997 and rs1420106, were found to be in strong linkage disequilibrium (LD) and were associated with post treatment improvement in disability (p = 0.02). Haplotype association analysis of 5 SNPs spanning across IL18RAP, IL18R1 and IL1A genes revealed significant associations with improvement in disability (p=0.02) and reduction in pain (p=0.04). An association was found between MMP3 polymorphism rs72520913 and improvement in pain (p = 0.03) and with severe degeneration (p = 0.006). Conclusions The findings of the current study suggest a role of variation at inflammatory and matrix degrading genes with severity of lumbar disc degeneration, pain and disability