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Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 229 - 229
1 Mar 2013
Kohan L Chou J Valenzuela S Santos J Milthorpe B Green D Otsuka M
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Gentamicin sulphate is a potent antibiotic, widely used by clinicians to treat Staphylococcus aureus bacterial complications in orthopaedic surgery and osteomyelitis. Antibiotics as administered are poorly localised and can accumulate with toxic effects. Achieving a better targeted release and controlled dosage has been an ongoing unmet microengineering challenge.

In this study we evaluated the antibiotic release potential of beta tricalcium phosphate (β-TCP) micro and macrospheres to eradicate Staphylococcus aureus and maintain osteoblast biocompatibility. Gentamicin was absorbed onto and within the spheres at an average amount of 4.2 mg per sample. Human osteoblast cell studies at five days incubation showed attachment and growth on the spheres surface with no detrimental effect on the cell viability. A time delayed antibacterial efficacy test was designed with the bacteria introduced at predetermined time intervals from 0–60 minutes.

We demonstrated that hydroxyapatite covered Foraminifera nano-, micro- macrospheres facilitated the slow release of the encapsulated pharmaceutical agent. Principally, this arises owing to their unique architecture of pores, struts and channels, which amplifies physiological degradation and calcium phosphate dissolution to release attached pharmaceuticals in a controlled manner. The Staphylococcus aureus growth response following exposure to the gentamicin incorporated microspheres at various time intervals showed the complete elimination of the bacteria within 30 minutes. Gentamicin release continued with no re-emergence of bacteria.

β-TCP nano to macro size spheres show promise as potential bone void filler particles with, in this case, supplementary delivery of antibiotic agent. Owing to their unique structure, excellent drug retention and slow release properties, they could be used in reconstructive orthopaedics to treat osteomyelitis caused by Staphylococcus aureus and possibly other sensitive organisms.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 87 - 87
1 Sep 2012
Kaneyama R Shiratsuchi H Oinuma K Otsuka M
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Introduction

Some authors have reported that if PCL is resected, flexion gap(FG) will become wider than extension gap(EG). Sacrifice or sparing of PCL influences the equality of EG and FG. Meanwhile, measured resection technique(MRT) and gap technique(GT) has different system to adjust gap and balance. There are no criteria for choosing between CR or PS component and MRT or GT nevertheless its influences on gap and balance in TKA.

Materials and Methods

EG and FG were measured intra-operatively with PCL intact to assess the characteristics of EG and FG. EG was created ordinarily. To measure FG before the final femoral cutting with PCL intact, small temporary FG was created by a pre-cut of the femoral posterior condyle with a 4-in-1 femoral cutting guide bigger than the measured size. After removal of all osteophytes, the gaps were measured by a tension device. To compare both gaps, FG was corrected by the amount of the pre-cut. According to EG and corrected FG, a component type was selected. If there was enough FG with PCL intact, CR component was implanted and if not, PS component was selected. If necessary, soft tissue was released. Finally, the optimal size of the femoral component for adequate EG and FG was estimated and rotation of the femoral component was decided. One hundred and fifty three knees with osteoarthritis were investigated.