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A Holiday Souvenir with Consequences - an Interdisciplinary Challenge

Background: cardiovascular disease is the number one killer in Qatar. Cardiac rehabilitation (CR) is a cost-effective model of care shown to reduce cardiovascular morbidity and mortality by 20%. However, it is vastly underutilized with low enrollment and adherence rates. This study aimed to (a) examine the association between number of sessions attended and change in cardiac risk factors after completion of CR program, and (b) investigate factors associated with adherence Methods: This is a retrospective cohort study, consisted of 714 cardiac patients, aged ≥18 years, referred to a cardiac rehabilitation program in Qatar. A simple linear regression analysis (unadjusted model) was used to assess the association between the mean change in each of the following risk factors: cholestrol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and body mass index (BMI and number of sessions attended. Then, we adjusted for clinical and sociodemographic factors that affect the outcome variable via multiple linear regression analyses. Logistic regression model was used to assess factors associated with adherence. Additionally, a paired sample t-test was used to identify mean change in cardiac risk factors pre-post CR and link this change to clinical significant cut off values in the literature. An independent sample t-test was used to identify change between groups (adherence vs. no adherence). Result: The mean age of the population was 52.7±10.1 years (mean ± SD). Patients referred to CR program were mostly males (n= 641, 89.8%) and non-Qatari (n= 596, 83.5%), almost one fourth were smokers (n=185, 25.91%), and one fifth (n=128, 18.8%) were diagnosed with severe depression. The main positive predictor for adherence was AACVPR moderate risk [OR=12.71, 95%CI= 7.81-20.68] and high-risk level [OR=10, 95%CI= 6.44-17.44]. PCI [OR=0.39, 95%CI= 0.17-0.89] and musculoskeletal disease [OR=0.17, 95%CI= 0.03-0.95] were negatively associated with adherence. We found clinically significant improvements among adherents to CR; 10% reduction in total cholesterol level and 15% reduction in low-density lipoproteins. Conclusion: This study provides new insights in Qatar setting into the factors that lead patients to adhere to their CR sessions. These patient-level variables associated with adherence represent opportunities for program directors in identifying patients who are less likely to adhere to the program; therefore, develope effective interventions to target these patients and consequently improve their health status.

Bioresorbable implants may serve as an alternative option for the fixation of bone fractures. Because of their minor inherent mechanical properties and insufficient anchorage within bone bioresorbable implants have so far been limited to mechanically nondemanding fracture types. By briefly liquefying the surface of the biomaterial during insertion, bioresorbable implants can be ultrasonically fused with bone to improve their mechanical fixation. The objective of this study was to investigate the biomechanical fixation performance and in vivo biocompatibility of an ultrasonically fused bioresorbable polymeric pin (SonicPin). First, we biomechanically compared the fused pin with press fitted metallic and bioresorbable polymeric implants for quasi-static and fatigue strength under shear and tensile loading in a polyurethane foam model. Second, fused implants were inserted into cancellous bovine bone and tested biomechanically to verify the reproducibility of their fusion behavior. Finally, the fused pins were tested in a lapine model of femoral condyle osteotomies and were histologically examined by light and transmission electron microscopy. While comparable under static shear loads, fixation performance of ultrasonically fused pins was significantly (p = 0.001) stronger under tensile loading than press fit implants and showed no pull-out. Both bioresorbable implants withstood comparable fatigue shear strength, but less than the K-wire. In bovine bone the ultrasonic fusion process worked highly reproducible and provided consistent mechanical fixation. In vivo, the polymeric pin produced no notable foreign body reactions or resorption layers. Ultrasonic fusion of polymeric pins achieved adequate and consistent mechanical fixation with high reproducibility and exhibits good short-term resorption and biocompatibility.

BACKGROUND After reamed nailing in long bones, there is a negligible amount of reaming debris at the fracture gap of A2 and A3 fractures. The aim of this study was to show whether there are differences between reamed nailing and reamed nailing with controlled intramedullary application of reaming debris at the fracture gap with an intramedullary application device. METHODS In this trial, 12 human femur specimens were used. On the medullary isthmus, 12 A3 fractures were artificially produced. Afterward, reduction was done by a monocortical external fixator, and closure of the fracture gap was done with a latex finger tip. Intramedullary reaming was performed for up to 10% of the bone cortex. In six femurs, the reaming procedure alone was performed, and in six human femurs, additional controlled application of reaming debris was done. For fixation, an intramedullary plastic implant was used. The region of interest was scanned with the μ-CT 80, and the fracture gap was contoured with digital imaging software. The threshold for the reaming debris was set at 365.6 mgHA/cm³. The analysis of the bone debris located at the fracture gap was measured by percent of debris volume to gap volume. For statistical analysis, the Wilcoxon test was used and a level of significance of p < 0.05 was chosen. RESULTS The fracture gap volume ranged from 7 mm³ to 29 mm³ without differences in both the groups. In the group without controlled intramedullary application, there was a median bone volume of 0.37 mm³ found at the fracture gap. In the group with controlled intramedullary application, a median of 2.2 mm³ of bone debris was found. The degree of filling of the fracture gap with bone debris was 2% without additional application and 13% with additional application, using the newly developed application device. CONCLUSIONS The results show that reaming debris at the fracture gap without additional application is negligible. When using an intramedullary application device, the amount of reaming debris at the fracture gap can be increased significantly.

The repair of bone defects can be induced experimentally with bone morphogenetic protein-2 (BMP-2) producing fat-derived stem cells, but this ex vivo tissue engineering method requires the isolation and long-term culture of autologous cells. To develop an expedited bone repair strategy, we transferred BMP-2 cDNA directly to autologous fat tissue fragments that were held in culture for only 24 h before implantation. We evaluated the ability of such gene-activated fat grafts to regenerate large segmental bone defects in rats. Fat tissue was harvested from 2 of 35 male Fischer 344 rats used for this study. The fat tissue fragments were incubated with an adenoviral vector carrying the cDNA encoding either BMP-2 or green florescent protein (GFP), or they remained unmodified. According to their group, the segmental femoral bone defects of 33 rats were filled press fit with either BMP-2-activated fat tissue, GFP-transduced fat tissue, or unmodified fat tissue. Another control group remained untreated. Femora were evaluated by radiographs, microcomputed tomography, biomechanical torsional testing, and histology. Radiographically and histologically, 100% of the femora treated with BMP-2-activated fat grafts were bridged at 6 weeks after surgery. The femora of this group exceeded the bone volume and the biomechanical stability of intact, contralateral femora. Control defects receiving no treatment, unmodified fat tissue, or GFP-transduced fat were filled with fibrous or adipose tissue, as evaluated by histology. The use of BMP-2 gene-activated fat tissue grafts represents an expedited and effective bone repair strategy that does not require the extraction and expansion of stem cells.

Numerous preclinical studies have shown that osseous defects can be repaired by implanting bone morphogenetic protein (BMP)-2-transduced muscle cells. However, the drawback of this treatment modality is that it requires the isolation and long-term (approximately 3 weeks) culture of transduced autologous cells, which makes this approach cumbersome, time-consuming, and expensive. Therefore, we transferred BMP-2 cDNA directly to muscle tissue fragments that were held in culture for only 24 hr before implantation. We evaluated the ability of such gene-activated muscle grafts to induce bone repair. Two of 35 male, syngeneic Fischer 344 rats used in this study served as donors for muscle tissue. The muscle fragments remained unmodified or were incubated with an adenoviral vector carrying the cDNA encoding either green fluorescent protein (GFP) or BMP-2. Critical-size defects were created in the right femora of 33 rats and remained untreated or were filled (press fitted) with either unmodified muscle tissue or GFP-transduced muscle tissue or with BMP-2-activated muscle tissue. After 6 weeks, femora were evaluated by radiography, microcomputed tomography (muCT), histology, and biomechanical testing. Six weeks after implantation of BMP-2-activated muscle grafts, 100% of the bone defects were bridged, as documented by radiographs and muCT imaging, and showed formation of a neocortex, as evaluated by histology. Bone volumes of the femora repaired by BMP-2-transduced muscle were significantly (p = 0.006) higher compared with those of intact femora and the biomechanical stability was statistically indistinguishable. In contrast, control defects receiving no treatment, unmodified muscle, or GFP-transduced muscle did not heal. BMP-2 gene-activated muscle grafts are osteoregenerative composites that provide an expedited means of treating and subsequently healing large segmental bone defects.

To determine distinguishing features between herniation pits (HPs) and other cystic-appearing lesions at the anterior femoral neck in multi-slice computed tomography (MSCT) and micro-computed tomography (microCT) examinations.Institutional review board approval was obtained to examine 37 proximal femora of 23 cadaveric specimens (mean age available in 19 cadavers, 83 years; range 68-100 years; 9 female, 8 male, 6 unknown). All 37 femora were investigated by MSCT. 23 femora, which revealed cystic-appearing lesions at the anterior femoral neck in MSCT examinations, were additionally examined by microCT. Cystic-appearing lesions were categorized by their location, sclerotic margin, demarcation and shape in MSCT with assessment of inter-observer agreement. Detailed cortical and trabecular properties were evaluated in microCT examinations.There were seven HPs in three femora. There were a number of abnormalities potentially imitating HPs, including focal osteoporosis (13 in 13 femora), degenerative changes (5 in 4 femora) and trabecular restructuring (5 in 4 femora) at the anterior femoral neck. HPs were differentiated on the basis of their subchondral/subcortical location, completely surrounding sclerosis, clear demarcation and round-to-oval shape in MSCT. Because of their location and their microscopic appearance, HPs seem to resemble intra-osseous ganglia at the anterior femoral neck.HPs have to be differentiated from other cystic appearing lesions at the anterior femoral neck to avoid overestimation of their incidence in the context of diagnosis of femoroacetabular impingement.

The aim of this study was to visualize the intramedullary bone debris after reamed nailing of long bones. To date, there is no protocol to quantify bone debris in the fracture gap. The hypothesis was to show if there are differences between A2 and A3 fractures. In this trial 17 sheep tibiae were used. On the medullary isthmus eight A2 und nine A3 fractures were produced. Afterwards, reposition, closure of the soft tissue and reaming procedure up to 10% of the bonecortex were done. For internal fixation, a plastic implant was used. The region of interest was scanned with the Micro-CT 80 and the fracture gap was contoured from a special software (SCANCO Medical AG, Switzerland). The threshold for the reaming debris was set at 549.9 mgHA/cm3. The analysis of the bone debris located at the fracture gap was measured by percent of debris volume to gap volume. For statistical analysis the Wilcoxon test was used and a level of significance of p < 0.05 was chosen. The fracture gap width ranged from 0.3 to 1.7 mm in both groups. Comparing A2 and A3 fractures there was no significant difference concerning the percentage of reaming debris at the fracture gap. The Median of A2 fractures was 20.5 and 21% for A3 fractures. The results show reaming produces intramedullary bonegrafting. Despite different fracture planes of A2 and A3 fractures, no significant differences in the amount of reaming debris located at the fracture gap could be found. However the percental rate of reaming debris at the fracture gap of plain fractures is negligible. This research shows that there is potential for reaming debris to be applied effectively as a prophylactic and osteogenetic autograft. Together with the high stability of the intramedullary nail an all embracing concept of osteosynthesis could be established.