Osteoprotegerin and Osteoprotegerin Ligand Expression in the Periprosthetic Tissue of Failed Hip Prosthesis

Objectives To investigate the effects of electroacupuncture (EA) on the oestradiol level, bone mineral density and osteoprotegerin ligand (OPGL) expression, and to explore whether EA might be a complementary method to prevent and treat osteoporosis. Methods A total of 21 New Zealand rabbits were randomly divided into three groups: a normal control (NC) group undergoing no surgery or EA; an ovariectomised (OVX) group, in which rabbits were ovariectomised but did not receive EA; an EA group, in which rabbits were ovariectomised and treated with EA. Acupuncture was applied at ST35, BL20 and BL23 points bilaterally. EA (10 Hz, 2 mA) was applied bilaterally at BL20 and BL23 for 30 min a day for 14 days. After 14 days, all animals were killed. OPGL expression level was determined by immunohistochemistry. Blood serum levels of oestradiol were measured by ELISA and bone mineral density was detected by dual-energy x-ray absorptiometry. Results After ovariectomy, the bone mineral density and oestradiol level decreased significantly in the OVX group compared with the NC group (p=0.001), whereas the OPGL expression level increased. After EA, the bone mineral density and oestradiol level increased compared with the OVX group (p=0.049 and p=0.012, respectively). The OPGL level OPGL level in the EA group was lower than that in the OVX group (p=0.022). Conclusions EA restored bone mineral density towards normal and was associated with increased plasma oestradiol level and reduced OPGL expression in an ovariectomised rabbit model of osteoporosis.

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Periprosthetic Tissue Removal in Minimally Invasive Hip Refix Procedures

Journal of Medical Devices ◽

10.1115/1.3442760 ◽

2010 ◽

Vol 4 (2) ◽

Author(s):

Gert Kraaij

Keyword(s):

Minimally Invasive ◽

Thermal Damage ◽

Hip Prosthesis ◽

Fibrous Tissue ◽

Clinical Situation ◽

Pulse Frequency ◽

Periprosthetic Tissue ◽

Ho:Yag Laser ◽

Tissue Removal

An alternative to conventional revision surgery of loosened hip prostheses is a new minimally invasive refixation procedure. This procedure requires the removal of periprosthetic fibrous tissue. The aim of this preliminary study is to evaluate which technique is most suitable for minimally invasive periprosthetic tissue removal: a Ho:YAG laser or a VAPR-2 coblation system. The clinical situation of a loosened prosthesis was simulated by several cadaveric femora, each implanted with a hip prosthesis. Artificially created periprosthetic lesions were filled with a fibrous tissue substitute. Using this fibrous tissue substitute, we measured temperatures in vitro at different distances from the site of removal. Temperatures during removal were recorded both inside the fibrous tissue and in the surrounding bone. This study demonstrated that temperatures generated in the bone do not result in thermal damage. Temperatures inside the fibrous tissue are sufficiently high to remove the fibrous tissue. Using the laser instead of the coblation system for the removal of fibrous tissue resulted in higher temperatures, thus, a faster removal of fibrous tissue. Additionally, the laser takes less effort to be integrated with the new surgical instrument and, therefore, we consider it a promising tool. However, when translating the results to clinical practice, the limitations of this study should be kept in mind. The equipment was set to typical presets; different settings (pulse frequency, pulse energy, and activated time) might affect the procedure’s success and risks. Care must be taken with respect to generated temperatures at larger distances from the place of removal. The use of the Ho:YAG laser, as well as VAPR coblation, might form a small risk for thermal damage to healthy surrounding tissues. Further research on apparatus settings and removal strategy is necessary before this technique can be applied for the removal of fibrous tissue in the clinical setting.

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Novel methods for demonstrating osseointegration of hydroxylapatite-coated titanium hip prostheses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084478 ◽

1991 ◽

Vol 49 ◽

pp. 34-35 ◽

Cited By ~ 1

Author(s):

P. Frayssinet ◽

J. Hanker ◽

D. Hardy ◽

B. Giammara

Keyword(s):

Hip Prosthesis ◽

Ethanol Concentration ◽

Bone Matrix ◽

Electron Microscopic Examination ◽

Electron Microscopic ◽

Hip Prostheses ◽

Cellular Inclusions ◽

Microscopic Studies ◽

Diamond Saw ◽

Plasma Sprayed

Prostheses implanted in hard tissues cannot be processed for electron microscopic examination or microanalysis in the same way as those in other tissues. For these reasons, we have developed methods allowing light and electron microscopic studies as well as microanalysis of the interface between bone and a metal biomaterial coated by plasma-sprayed hydroxylapatite(HA) ceramic.An HA-coated titanium hip prosthesis (Corail, Landos, France), which had been implanted for two years, was removed after death (unrelated to the orthopaedic problem). After fixation it was dehydrated in solutions of increasing ethanol concentration prior to embedment in polymethylmethacrylate(PMMA). Transverse femur sections were obtained with a diamond saw and the sections then carefully ground to a thickness of 200 microns. Plastic-embedded sections were stained for calcium with a silver methenamine modification of the von Kossa method for calcium staining and coated by carbon. They have been examined by back-scatter SEM on an ISI-SS60 operated at 25 KV. EDAX has been done on cellular inclusions and extracellular bone matrix.

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