Arthroscopic Mumford procedure utilizing the anteromedial and Neviaser portals – a pilot cadaveric study on neurovascular structures at risk

Introduction: Degenerative disorder involving the acromio-clavicular joint (ACJ) is quite common especially in the elderly. One of the surgical modalities of treatment of this disorder is the Mumford Procedure. Arthroscopic approach is preferred due to its reduced morbidity and faster post-operative recovery. One method utilizes the anteromedial and Neviaser portals, which allow direct and better visualization of the ACJ from the subacromial space. However, the dangers that may arise from incision and insertion of instruments through these portals are not fully understood. This cadaveric study was carried out to investigate the dangers that can arise from utilization of these portals and which structures are at risk during this procedure. Methods: Arthroscopic Mumford procedures were performed on 5 cadaver shoulders by a single surgeon utilizing the anteromedial and Neviaser portals. After marking each portals with methylene blue, dissection of nearby structures were carried out immediately after each procedure was completed. Important structures (subclavian artery as well as brachial plexus and its branches) were identified and the nearest measurements were made from each portal edges to these structures. Results: The anteromedial portal was noted to be closest to the suprascapular nerve (SSN) at 2.91 cm, while the Neviaser portal was noted to be closest also to the SSN at 1.60 cm. The suprascapular nerve was the structure most at risk during the Mumford procedure. The anteromedial portal was noted to be the most risky portal to utilize compared to the Neviaser portal. Conclusion: Extra precaution needs to be given to the anteromedial portal while performing an arthroscopic distal clavicle resection in view of the risk of injuring the suprascapular nerve of the affected limb

Characterisation and immunosuppressive activity of human cartilage-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) exert potent immuno-regulatory activities on various immune cells and also differentiate into various mesodermal lineages besides retaining a distinct self-renewal ability. Such exclusive characteristics had enabled MSCs to be recognised as an ideal source for cell-based treatment in regenerative medicine and immunotherapy. Thus, considering MSCs for treating degenerative disease of organs with limited regenerative potential such as cartilage would serve as an ideal therapy. This study explored the feasibility of generating human cartilage-derived MSCs (hC-MSCs) from sports injured patients and characterised based on multipotent differentiation and immunosuppressive activities. Cartilage tissues harvested from a non-weight bearing region during an arthroscopy procedure were used to generate MSCs. Despite the classic morphology of fibroblast-like cells and a defined immunophenotyping, MSCs expressed early embryonic transcriptional markers (SOX2, REX1, OCT4 and NANOG) and differentiated into chondrocytes, adipocytes and osteocytes when induced accordingly. Upon co-culture with PHA-L activated T-cells, hC-MSCs suppressed the proliferation of the T-cells in a dose-dependent manner. Although, hC-MSCs did not alter the activation profile of T cells significantly, yet prevented the entering of activated T cells into S phase of the cell cycle by cell cycle arrest. The present study has strengthened the evidence of tissue-resident mesenchymal stem cells in human cartilage tissue. The endogenous MSCs could be an excellent tool in treating dysregulated immune response that associated with cartilage since hC-MSCs exerted both immunosuppressive and regenerative capabilities

Fluorescence microscopy on the biocompatibility of gentamicin-coated hydroxyapatite (HA) material on osteoblast

This study was carried out to observe the biocompatibility of gentamicin-coated hydroxyapatite (HA) on osteoblast using fluorescence microscopy. The specific objective was to observe the viability of the osteoblast on the gentamicin-coated hydroxyapatite (HA) and to determine the effect of the biomaterial coated with gentamicin on the osteoblast. Osteoblast cell lines were cultured and maintained in complete medium, 1:1 HAM's F12 Medium Dulbecco's modified Eagle's medium without phenol red (DMEM) and incubated at 37°C in a 5% CO 2. The cell lines were treated with different concentration of gentamicin-coated hydroxyapatite and the interactions of the antibiotic beads against osteoblast were tested using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The MTT assay results indicated that varying concentrations of gentamicin coated HA from 0.1 mg/ml to 10 mg/ml did not significantly affect viability of osteoblast. By employing fluorescence microscopy, the morphology of osteoblast observed appeared red in color which indicated that the osteoblast was viable on biomaterial. The pore size of hydroxyapatite is between 150 to 350 nm. This preliminary result suggested that the gentamicin-coated HA had a good biocompatibility towards osteoblast

Cytotoxic effect of gentamycin-coated hydroxyapatite on Staphylococcus aureus biofilm.

A biofilm is a multilayered complex microorganism, which attached on a surface and resistant to antibiotics. In this study, we examined the cytotoxicity of the HA biomaterial coated with gentamycin on S. aureus biofilm. The microtiter plate biofilm assay and catheter-associated biofilm had been described in this study. The surface morphology of S. aureus biofilm was examined under scanning electron microscope (SEM). The IC50 of gentamycincoated HA treated on S. aureus biofilm was 0.1mg/ml (100μg/ml)

Fluorescence microscopy on the biocompatibility of gentamicin-coated hydroxyapatite (HA) material on osteoblast

This study was carried out to observe the biocompatibility of gentamicin-coated hydroxyapatite (HA) on osteoblast using fluorescence microscopy. The specific objective was to observe the viability of the osteoblast on the gentamicin-coated hydroxyapatite (HA) and to determine the effect of the biomaterial coated with gentamicin on the osteoblast. Osteoblast cell lines were cultured and maintained in complete medium, 1:1 HAM's F12 Medium Dulbecco's modified Eagle's medium without phenol red (DMEM) and incubated at 37°C in a 5% CO2. The cell lines were treated with different concentration of gentamicin-coated hydroxyapatite and the interactions of the antibiotic beads against osteoblast were tested using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The MTT assay results indicated that varying concentrations of gentamicin coated HA from 0.1 mg/ml to 10 mg/ml did not significantly affect viability of osteoblast. By employing fluorescence microscopy, the morphology of osteoblast observed appeared red in color which indicated that the osteoblast was viable on biomaterial. The pore size of hydroxyapatite is between 150 to 350 nm. This preliminary result suggested that the gentamicin-coated HA had a good biocompatibility towards osteoblast

In vitro elution and dissolution of tobramycin and gentamicin from calcium phosphate

This study was conducted to investigate the in vitro drug release characteristics of tobramycin and gentamicin from calcium phosphate. Calcium phosphate beads were loaded with tobramycin and gentamicin separately to form 2 types of antibiotic beads to generate antibiotic drug delivery system for the treatment of osteomyelitis. Tobramycin and gentamicin concentrations were determined spectrophotometrically by measuring the absorbance at 400 nm. The standard graphs for tobramycin and gentamicin concentration versus absorbance reading were prepared as references to identify the concentration of the drugs release after incorporating calcium phosphate over 8 weeks. This study showed that incorporating tobramycin and gentamicin with calcium phosphate provided slow residual release of antibiotic from 30 min to 1344 h (8 weeks) and dissolution of calcium phosphate. In this respect, the drug delivery systems of tobramycin and gentamicin-incorporated calcium phosphate have potential of controlling drug release

Biocompatibility of Gentamicin-coated Hydroxyapatite (Ha) with osteoblast.

This study was carried out to compare the surface morphological changes and cell-to-cell attachment with different concentrations of gentamicin-coated hydroxyapatite (HA) on the osteoblast cell lines. Osteoblast cell lines were cultured and maintained in complete medium, 1:1 HAM’s F12 Medium Dulbecco's modified Eagle's medium without phenol red (DMEM) and incubated at 37oC in 5% CO2. The cell lines were treated with gentamicin-coated HA and undergone the 3-(4,5-di-methylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) assay. After 72 hours treatment, the gentamicin-coated HA was processed for viewing the morphological changes by using scanning electron microscopy. The MTT assay results indicated that varying concentrations of gentamicin coated hydroxyapatite do not significantly affect viability of osteoblast. The osteoblast-like cells attached and spread well on the surface of hydroxyapatite and grew into the pores. In conclusion, the gentamicin-coated HA is biocompatible towards osteoblast