The effect of strontium ranelate on the healing of a fractured ulna with bone gap in rabbit.

BACKGROUND: Fracture healing in bone gap is one of the major challenges encountered in Orthopedic Surgery. At present, the treatment includes bone graft, employing either internal or external fixation which has a significant impact on the patient, family and even society. New drugs are emerging in the markets such as anabolic bone-forming agents including teriparatide and strontium ranelate to stimulate bone growth. Based on the mechanism of their actions, we embarked on a study on the healing of a fractured ulna with bone gap in a rabbit model. We segregated ten rabbits into two groups: five rabbits in the test group and five rabbits in the control group. We created a 5 mm bone gap in the ulna bone, removing the periosteum as well. Rabbits in the test group received 450 mg/kg of strontium ranelate via oral administration, daily, for six weeks. The x-rays, CT scans and blood tests were performed every two weeks. At the end of six weeks, the rabbits were sacrificed, and the radius and ulna bones harvested for histopathological examination. RESULTS: Based on the x-rays and CT scans, fracture healing or bone formation was observed to be faster in the control group. From the x-ray findings, 80 % of the fracture united and by CT scan, 60 % of the fracture united in the control group at the end of the six-week study. None of the fractures united in the test group. However, the histopathology report showed that a callus of different stages was being formed in both groups, consisting of 80 % of bone. The serum levels of osteocalcin and alkaline phosphatase initially remained similar up to three weeks and changed slightly at the end of six weeks. CONCLUSIONS: We conclude that the strontium effect begins slowly, and while it may not interfere with bone cell proliferation it may interfere in the mineralization and delay the acute stage of fracture healing. We recommend that a larger sample size and a longer duration of the study period be implemented to confirm our finding.

A comparative study on morphochemical properties and osteogenic cell differentiation within bone graft and coral graft culture systems.

The objective of this study was to compare the morphological and chemical composition of bone graft (BG) and coral graft (CG) as well as their osteogenic differentiation potential using rabbit mesenchymal stem cells (rMSCs) in vitro. SEM analysis of BG and CG revealed that the pores in these grafts were interconnected, and their micro-CT confirmed pore sizes in the range of 107-315 µm and 103-514 µm with a total porosity of 92% and 94%, respectively. EDS analysis indicated that the level of calcium in CG was relatively higher than that in BG. FTIR of BG and CG confirmed the presence of functional groups corresponding to carbonyl, aromatic, alkyl, and alkane groups. XRD results revealed that the phase content of the inorganic layer comprised highly crystalline form of calcium carbonate and carbon. Atomic force microscopy analysis showed CG had better surface roughness compared to BG. In addition, significantly higher levels of osteogenic differentiation markers, namely, alkaline phosphatase (ALP), Osteocalcin (OC) levels, and Osteonectin and Runx2, Integrin gene expression were detected in the CG cultures, when compared with those in the BG cultures. In conclusion, our results demonstrate that the osteogenic differentiation of rMSCs is relatively superior in coral graft than in bone graft culture system.

Supermacroporous poly(vinyl alcohol)-carboxylmethyl chitosan-poly(ethylene glycol) scaffold: an in vitro and in vivo pre-assessments for cartilage tissue engineering.

This study aims to pre-assess the in vitro and in vivo biocompatibility of poly(vinyl alcohol)-carboxylmethyl-chitosan-poly(ethylene glycol) (PCP) scaffold. PCP was lyophilised to create supermacroporous structures. 3-(4, 5-dimethyl-thiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and immunohistochemistry (IHC) were used to evaluate the effectiveness of PCP scaffolds for chondrocytes attachment and proliferation. The ultrastructural was assessed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Extracellular matrix (ECM) formation was evaluated using collagen type-II staining, glycosaminoglycan (GAG) and collagen assays. Histological analysis was conducted on 3-week implanted Sprague-Dawley rats. The MTT, IHC, SEM and TEM analyses confirm that PCP scaffolds promoted cell attachment and proliferation in vitro. The chondrocyte-PCP constructs secreted GAG and collagen type-II, both increased significantly from day-14 to day-28 (P < 0.05). PCP scaffolds did not elicit any adverse effects on the host tissue, but were partially degraded. These results suggest that supermacroporous PCP is a biocompatible scaffold for clinical applications.

Falsarthrobacter nasiphocae periprosthetic joint infection.

We report the isolation of a rare Gram-positive coccobacillary bacterium from synovial fluids of a patient with periprosthetic joint infection on three occasions over an 8-month period. As routine microbiological methods were not able to identify the isolate definitely, sequence analyses of the bacterial 16S ribosomal RNA gene and whole genome were performed. Analysis of the bacterial 16S ribosomal RNA gene showed the highest similarity (98.1%) with that of Falsarthrobacter (previously known as Arthrobacter) nasiphocae, which was first isolated from the nasal cavities of common seals (Phoca vitulina). The genome size of the strain (designated as UM1) is 2.4 Mb. With a high G+C content (70.4 mol%), strain UM1 is phylogenetically most closely related to F. nasiphocae based on whole genome analysis. Strain UM1 was susceptible to vancomycin, linezolid, trimethoprim-sulfamethoxazole, doxycycline, and intermediate to penicillin and ciprofloxacin. Ceftriaxone resistance was noted. The patient who was also on hemodialysis for his end stage kidney disease died approximately 3 weeks following implant removal and fusion with an external fixator. This study describes the first isolation of F. nasiphocae from human clinical samples. The use of emerging technologies has supported more definitive etiological diagnosis associated with rarely encountered organisms in periprosthetic joint infection.

Are Two- and Three-Dimensional Computed Tomographic Scan Measurements of Tibial Tubercle-Trochlear Groove Distance Equivalent? A Comparative Study.

Background: Accurate planning for patellar instability correction is important in obtaining good post-operative outcome. The main challenge in the current two-dimensional (2-D) computed tomographic (CT) scans method is the difficulty in choosing reliable bony landmarks. This study aimed to compare the reliabilities between the 2-D and three-dimensional (3-D) methods of measuring tibial tubercle-trochlear groove (TT-TG) distance. We hypothesize that the proposed 3-D method will result in measurements with narrower error margin, providing higher reliability and accuracy. Materials and Methods: We traced CT scans of 106 knees with no patellofemoral pathology from 59 subjects from the database system and converted all 2-D images into 3-D models to determine the values for each parameter. We compared the intra- and interobserver reliability of each method using intraclass correlation (ICC) and Bland-Altman method. Results: The values of TT-TG measured by 2-D and 3-D methods were 16.1 ± 4.6 mm and 16.2 ± 4.2 mm, respectively. The ICC values of both methods were comparable (95% limits of agreement between the same observer: - 3.3 to 3.8 mm versus - 2.4 to 2.7 mm and different observers: - 4.3 to 4.9 mm versus - 3.9 to 2.7 mm), with 3-D method results in narrower limits of agreement. Conclusion: TT-TG measurement is reliable using the 2-D method without using advanced radiographic software. The 3-D method of measuring TT-TG provides measurement with narrower variation when compared with the 2-D method. However, both TT-TG distances' measurement methods in the current study were comparable as the variations are not significant.

Tibia vara in Asians: Myth or fact? Verification with three-dimensional computed tomography.

BACKGROUND: There is a common perception among surgeons that Asian tibiae are significantly more varus compared to non-Asians, contributed both by an acute medial tibial proximal angle (MPTA) and diaphyseal bowing. Insight into the normative morphology of the tibia allows generation of knowledge towards disease processes and subsequently planning for corrective surgeries. METHODS: Computed tomography (CT) scans of 100 normal adult knees, aged 18 years and above, were analysed using a 3-dimensional (3D) analysis software. All tibiae were first aligned to a standard frame of reference and then rotationally aligned to the tibial centroid axis (TCAx) and the transmalleolar axis (tmAx). MPTA was measured from best-fit planes on the surface of the proximal tibia for each rotational alignment. Diaphyseal bowing was assessed by dividing the shaft to three equal portions and establishing the angle between the proximal and distal segments. RESULTS: The mean MPTA was 87.0° ± 2.2° (mean ± SD) when rotationally aligned to TCAx and 91.6° ± 2.7° when aligned to tmAx. The mean diaphyseal bowing was 0.1° ± 1.9° varus when rotationally aligned to TCAx and 0.3° ± 1.6° valgus when aligned to tmAx. The mean difference when the MPTA was measured with two different rotational alignments (TCAx and tmAx) was 4.6° ± 2.3°. No statistically significant differences were observed between males and females. Post hoc tests revealed statistically significant difference in MPTA between different ethnic sub-groups. CONCLUSION: The morphology of the proximal tibiae in the disease-free Asian knee is inherently varus but not more so than other reported populations. The varus profile is contributed by the MPTA, with negligible diaphyseal bowing. These implications are relevant to surgical planning and prosthesis design.

Modulation of the mechanical responses of synovial fibroblasts by osteoarthritis-associated inflammatory stressors.

OBJECTIVES: To compare mechanobiological response of synovial fibroblasts (SFb) from OA patient cohorts under mechanical load and inflammatory stressors for better understanding of SFb homeostatic functions. METHODS: Primary SFb isolated from knee synovium of OA obese (OA-ob:SFb), OA-pre-obese (OA-Pob:SFb), non-OA arthroscopic (scope:SFb), and non-OA arthroscopic with cartilage damage (scope-CD:SFb) were exposed to OA-conditioned media (OACM), derived from OA obese (OA-ob:CM), OA-pre-obese (OA-Pob:CM), and mechanical stretch at either 0 %, 6 % or 10 % for 24 h. Differences in the mRNA levels of genes involved in extracellular matrix production, inflammation and secretory activity were measured. RESULTS: Despite the significant BMI differences between the OA-ob and OA-Pob groups, OA-Pob has more patients with underlying dyslipidaemia, and low-grade synovitis with higher levels of secreted proteins, CXCL8, COL4A1, CCL4, SPARC and FGF2 in OA-Pob:CM. All primary SFb exhibited anti-proliferative activity with both OA-CM. Mechanical stretch stimulated lubricin production in scope:SFb, higher TGFß1 and COL1A1 expressions in scope-CD:SFb. OA-Pob:CM stimulated greater detrimental effects than the OA-ob:CM, with higher pro-inflammatory cytokines, IL1ß, IL6, COX2 and proteases such as aggrecanases, ADAMTS4 and ADAMTS5, and lower ECM matrix, COL1A1 expressions in all SFb. OA-ob:SFb were unresponsive but expressed higher pro-inflammatory cytokines under OA-Pob:CM treatment. CONCLUSION: Both mechanical and inflammatory stressors regulate SFb molecular functions with heterogeneity in responses that are dependent on their pathological tissue of origins. While mechanical stretch promotes a favorable effect with enhanced lubricin production in scope:SFb and TGFß1 and COL1A1 in scope-CD:SFb, the presence of excessively high OA-associated inflammatory mediators in OA-Pob:CM, predominantly SPARC, CXCL8 and FGF2 drive all SFb regardless of pathology, towards greater pro-inflammatory activities.

Uniaxial Cyclic Tensile Stretching at 8% Strain Exclusively Promotes Tenogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stromal Cells.

The present study was conducted to establish the amount of mechanical strain (uniaxial cyclic stretching) required to provide optimal tenogenic differentiation expression in human mesenchymal stromal cells (hMSCs) in vitro, in view of its potential application for tendon maintenance and regeneration. Methods. In the present study, hMSCs were subjected to 1 Hz uniaxial cyclic stretching for 6, 24, 48, and 72 hours; and were compared to unstretched cells. Changes in cell morphology were observed under light and atomic force microscopy. The tenogenic, osteogenic, adipogenic, and chondrogenic differentiation potential of hMSCs were evaluated using biochemical assays, extracellular matrix expressions, and selected mesenchyme gene expression markers; and were compared to primary tenocytes. Results. Cells subjected to loading displayed cytoskeletal coarsening, longer actin stress fiber, and higher cell stiffness as early as 6 hours. At 8% and 12% strains, an increase in collagen I, collagen III, fibronectin, and N-cadherin production was observed. Tenogenic gene expressions were highly expressed (p < 0.05) at 8% (highest) and 12%, both comparable to tenocytes. In contrast, the osteoblastic, chondrogenic, and adipogenic marker genes appeared to be downregulated. Conclusion. Our study suggests that mechanical loading at 8% strain and 1 Hz provides exclusive tenogenic differentiation; and produced comparable protein and gene expression to primary tenocytes.

Femoral head diameter in the Malaysian population.

INTRODUCTION: Hip arthroplasty is commonly performed worldwide. The objective of this study was to determine the diameter of the femoral head in the Malaysian population in relation to gender and race (i.e. among Malay, Chinese and Indian patients). METHODS: This was a retrospective cross-sectional study performed between January 1995 and December 2006, evaluating the femoral head diameters of all patients aged 50 years and above who underwent hemiarthroplasty at two major hospitals in Malaysia. RESULTS: A total of 945 femoral heads (663 women, 282 men) were evaluated. The mean age of the patients in our cohort was 75.2 ± 9.4 (range 50-101) years. The mean femoral head diameter (with intact articular cartilage) was 44.9 ± 3.2 (range 38-54) mm. In our study, men had a significantly larger mean femoral head diameter than women (47.7 ± 2.8 mm vs. 43.7 ± 2.4 mm; p < 0.05). Patients of Chinese ethnicity were also found to have significantly larger femoral head diameters, when compared among the three races studied (p < 0.05). CONCLUSION: Malaysians have a mean femoral head diameter of 44.9 ± 3.2 mm. Among our patients, Chinese patients had a significantly larger femoral head size than Malay and Indian patients. We also found that, in our cohort, men had significantly larger femoral head diameters than women.

Total cell pooling in vitro: an effective isolation method for bone marrow-derived multipotent stromal cells.

In vitro cellular proliferation and the ability to undergo multilineage differentiation make bone marrow-derived multipotent stromal cells (MSCs) potentially useful for clinical applications. Several methods have been described to isolate a homogenous bone marrow-derived MSCs population; however, none has been proven most effective, mainly due to their effects on proliferation and differentiation capability of the isolated cells. It is hypothesized that our newly established total cell pooling method may provide a better alternative as compared to the standard isolation method (density gradient centrifugation method). For the total cell pooling method, MSCs were isolated from rabbit bone marrow and were subsequently cultured in the growth medium without further separation as in the standard isolation method. The total cell pooling method was 65 min faster than the standard isolation method in completing cell isolation. Nevertheless, both methods did not differ significantly in the number of primary viable cells and population doubling time in the cultures (p > 0.05). The isolated cells from both methods expressed CD29 and CD44 markers, but not CD45 markers. Furthermore, they displayed multilineage differentiation characteristics of chondroblasts, osteoblasts, and adipocytes. In conclusion, both methods provide similar efficiency in the isolation of rabbit bone marrow-derived MSCs; however, the total cell pooling method is technically simpler and more cost effective than the standard isolation method.