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Utsunomiya-shi, Japan

Tanaka T.,NHO Utsunomiya National Hospital
Techniques in Orthopaedics | Year: 2013

With the improvement of bone substitutes and fixation plates, opening wedge high tibial osteotomy (HTO) has become popular. This study reports a technical approach used in the application of porous β-tricalcium phosphate (β-TCP) blocks for patients undergoing a medial opening wedge HTO. Most of the implanted porous β-TCP can be resorbed. However, a β-TCP block with 75% porosity is inadequate for weight-bearing sites until bone incorporation occurs. Thus, we have recently developed β-TCP block with 60% porosity, which is approximately 7-fold greater in terms of compressive strength than that of β-TCP with 75% porosity. During opening HTO, the opened defect was fixed with a Puddu plate, after which β-TCP with 75% porosity was used to fill the cancellous bone defect, except on the medial cortical bone side where wedge-shaped TCP blocks with 60% porosity were implanted in front and back of the plate. The use of β-TCP blocks with 60% porosity avoided autogenous bone grafting and shortened the surgical time. Copyright © 2013 by Lippincott Williams &Wilkins.

Tanaka T.,NHO Utsunomiya National Hospital | Tanaka T.,Jikei University School of Medicine | Saito M.,Jikei University School of Medicine | Chazono M.,Jikei University School of Medicine | And 4 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2010

The aim of this study was to determine the effects of alendronate (ALN) on osteoclastic resorption of β-tricalcium phosphate (β-TCP) and bone formation. β-TCP blocks of 75% porosity, with or without ALN treatment, were implanted into cavities drilled in rabbit femoral condyles. New bone formation, residual amount of β-TCP, and the number of tartrate-resistant acid phosphatase-positive cells were evaluated 2 weeks after surgery. The results show that local application of ALN at a concentration of 10-2 to 10-6M reduced the number of osteoclasts on the surface of β-TCP. New bone formation was also inhibited by ALN in a dose-dependent manner. Thus, inhibition of osteoclast formation resulted in reduced β-TCP resorption and bone formation. These results suggest that osteoclast-mediated resorption plays an important role in bone formation and a coupling-like phenomenon could occur in β-TCP-filled bone defects. © 2009 Wiley Periodicals, Inc.

Tanaka T.,NHO Utsunomiya National Hospital | Kumagae Y.,NHO Utsunomiya National Hospital | Chazono M.,NHO Utsunomiya National Hospital | Kitasato S.,Jikei University School of Medicine | And 2 more authors.
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2015

Purpose: The aim of this study was to establish an evaluation system to monitor bone formation and beta-tricalcium phosphate (TCP) resorption in opening high tibial osteotomy (HTO). Methods: From 2003 to 2005, opening HTO was performed in 36 patients using a Puddu plate and β-TCP blocks with 60 and 75 % porosity. Thirty-one patients were used for evaluation. All patients underwent CT examination at 2 weeks and 6 years. The CT image data were divided into three areas, and CT values of each area were analysed using the imaging software, Osirix. Results: CT image analysis at 2 weeks showed that the mean CT-attenuation values (in Hounsfield units) of the implanted area with β-TCP of 60 % porosity, the implanted area with β-TCP of 75 % porosity, and cancellous bone were, 1,694.0 ± 94.2, 1,010.9 ± 81.1, and 178.0 ± 45.1, respectively. Six years after surgery, these values were 574.1 ± 273.5, 168.8 ± 75.1, and 174.9 ± 69.3, respectively. Conclusion: β-TCP with 75 % porosity was completely resorbed and replaced by bone. β-TCP with 60 % porosity was resorbed, but approximately 1/3 still remained even 6 years after surgery. The imaging software, Osirix, enabled scanning of the whole area to measure CT values. This system is the first to quantitatively evaluate β-TCP resorption and bone formation in opening HTO. Level of evidence: Laboratory studies. © 2014, The Author(s).

Tanaka T.,NHO Utsunomiya National Hospital | Kumagae Y.,NHO Utsunomiya National Hospital | Chazono M.,NHO Utsunomiya National Hospital | Komaki H.,Jikei University School of Medicine | And 3 more authors.
Open Biomedical Engineering Journal | Year: 2014

We evaluated the effects of an injectable complex of β-tricalcium phosphate (β-TCP) granules, hyaluronate, and recombinant human fibroblast growth factor-2 (rhFGF-2) on repair of unstable intertrochanteric fractures in elderly patients. Twenty-five patients (range, 76-91 years) having 31.A2 fractures (AO classification) were treated with injection of the complex followed by intramedullary nails. Bone regeneration and β-TCP resorption, unions of intertrochanteric fractures and displaced lesser trochanters to the shaft, and varus deformity of the femoral neck were assessed by X-ray and CT scans. Fracture union occurred in all cases and union of the displaced lesser trochanter to the shaft was obtained in 24 cases by 12 weeks. It is of interest that β-TCP granules were completely resorbed and marked new bone formation around the lesser trochanter was observed in all cases compared to cases not treated with the complex. Based on the results of intertrochanteric fractures, we applied this technique to two patients with subtrochanteric or humeral fractures in elderly patients, and obtained bone union. This complex is a paste-like material that is easy to handle, and it may be of considerable use in treatment of both unstable intertrochanteric fractures and other cortical bone defects with minimal surgical invasion. © 2015 Tanaka.

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