Colonization of bacteria around native host cells or polymeric implant surfaces results in a dense growth on the surface, which leads to infection. The change of a bacterium from a motile planktonic to a nonmotile long chain of growing cells is a complex, regulated process that depends on several factors. The probability of a biofilm-related infection occurrence is between 65 and 80%. This review critically evaluates the mode of biofilm formation on native tissues and orthopedics, dental, cardiac, and urological implants and vascular grafts. The combination of biochemical advancements with conventional microbiological techniques and the use of radio-labeled monoclonal antibodies in imaging techniques, with recent developments in the detection of these biofilm in vivo, would help in designing biomaterials that prevent bacterial adhesion and biofilm formation, and dislodge the formed biofilm, thereby accelerating the product development phase.

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BackgroundUse of antibiotic-loaded acrylic bone cement to treat orthopaedic infections continues to remain popular, but resistance to routinely used antibiotics has led to the search for alternative, more effective antibiotics. We studied, in vitro, the elution kinetics and bio-activity of different concentrations of meropenem-loaded acrylic bone cement.MethodsMeropenem-loaded bone cement cylinders of different concentrations were serially immersed in normal saline. Elution kinetics was studied by measuring the drug concentration in the eluate, collected at pre-determined intervals, by high-performance liquid chromatography. Bio-activity of the eluate of two different antibiotic concentrations was tested for a period of 3 weeks against each of the following organisms: Staphylococcus aureus ATCC 2593 (MSSA), Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, S. aureus ATCC 43300 (MRSA) and Klebsiella pneumoniae ATCC 700603 (ESBL).ResultsMeropenem elutes from acrylic bone cement for a period of 3–27 days depending on the concentration of antibiotic. Higher doses of antibiotic concentration resulted in greater elution of the antibiotic. The eluate was found to be biologically active against S. aureus ATCC 2593 (MSSA), P. aeruginosa ATCC 27853, E. coli ATCC 25922 and K. pneumoniae ATCC 700603 (ESBL) for a period of 3 weeks.ConclusionsThe elution of meropenem is in keeping with typical antibiotic-loaded acrylic bone cement elution characteristics. The use of high-dose meropenem-loaded acrylic bone cement seems to be an attractive option for treatment of resistant Gram-negative orthopaedic infections but needs to be tested in vivo.

This study aimed to determine the efficacy of PEMF (pulsed electromagnetic field) treatment in experimental osteochondral defect healing in a rabbit model. The study was conducted on 12 New Zealand white rabbits. Six rabbits formed the study group and six rabbits the control group. The right knee joints of all 12 animals were exposed and a 3.5-mm diameter osteochondral defect was created in the trochlear groove. The defect was filled with calcium phosphate scaffold. Six animals from the study group were given PEMF of one hour duration once a day for six weeks with set parameters for frequency of 1 Hz, voltage 20 V, sine wave and current ±30 mA. At six weeks the animals were sacrificed and histological evaluation was done using H&E, Safranin O, Maissons trichrome staining and immunohistochemistry for type 2 collagen. The quality of the repair tissue was graded and compared between groups with the Wakitani histological grading scale and a statistical analysis was done. The total histological score was significantly better in the study group (p =0.002) with regeneration similar to adjacent normal hyaline cartilage. Immunohistochemistry for collagen type II was positive in the study group. PEMF stimulation of osteochondral defects with calcium phosphate scaffold is effective in hyaline cartilage formation. PEMF is a non-invasive and cost effective adjuvant treatment with salvage procedures such as abrasion chondroplasty and subchondral drilling.

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