[Visualization of Anterolateral Ligament of the Knee Using 3D Reconstructed Variable Refocus Flip Angle-Turbo Spin Echo T2 Weighted Image].

Anterolateral ligament (ALL) is one of the lateral structures in the knee that contributes to the internal rotational stability of tibia. ALL has been referred to in some recent reports to re-emphasize its importance. We visualized the ALL on 3D-MRI in 32 knees of 27 healthy volunteers (23 male knees, 4 female knees; mean age: 37 years). 3D-MRIs were performed using 1.5-T scanner [T(2) weighted image (WI), SPACE: Sampling Perfection with Application optimized Contrast using different flip angle Evolutions] in the knee extended positions. The visualization rate of the ALL, the mean angle to the lateral collateral ligament (LCL), and the width and the thickness of the ALL at the joint level were investigated. The visualization rate was 100%. The mean angle to the LCL was 10.6 degrees. The mean width and the mean thickness of the ALL were 6.4 mm and 1.0 mm, respectively. The ALL is a very thin ligament with a somewhat oblique course between the lateral femoral epicondyle and the mid-third area of lateral tibial condyle. Therefore, the slice thickness and the slice angle can easily affect the ALL visualization. 3D-MRI enables acquiring thin-slice imaging data over a relatively short time, and arbitrary sections aligned with the course of the ALL can later be selected.

Remodeling of heat-treated cortical bone allografts for posterior lumbar interbody fusion: serial 10-year follow-up.

We have selected heat-treated bone allografts as the graft material since the Tokai Bone Bank, the first regional bone bank in Japan, was established in 1992. In this study, we examined changes in bone mineral density (BMD), and morphology observed by magnetic resonance imaging (MRI), and histological findings of bone grafts in cases followed up for 7-10 years after bone grafting to grasp the remodeling of heat-treated cortical bone allografts for posterior lumber interbody fusion (PLIF). BMD of bone grafts was reduced by half at 10 years after grafting. MRI revealed that bone grafts were indistinguishable initially in only 22.2% of cases, whereas after a lengthy period of 10 years distinguishable in many cases. Histologically, new bone formation at the graft-host interface was observed earlier, at 1 year after grafting, than that at the periphery of canals in the specimens. The laminated structure of the cortical bone eroded over time, and fragmented bone trabeculae were observed in the specimens at 8 years or longer after grafting, though necrotic bone still remained in some sites.

Serial evaluation of human anterior cruciate ligament grafts by contrast-enhanced magnetic resonance imaging: comparison of allografts and autografts.

PURPOSE: The purpose of this study was to clarify the difference in remodeling between allografts and autografts in anterior cruciate ligament reconstruction. METHODS: We examined 24 knees with bone-patellar tendon-bone allografts and 20 knees with central-third bone-patellar tendon-bone autografts. Surgical patients from January 1997 to December 2002 were included in the study, and more than 1 year had passed since surgery. The mean postoperative follow-up was 24.0 months in the allograft group and 21.3 months in the autograft group. Patients with a positive Lachman test were excluded. The operative method and postoperative rehabilitation programs were the same. All allografts were provided by Tokai Regional Bone Bank, the only regional bone bank in Japan. Contrast-enhanced magnetic resonance imaging (1.0 T, T1-weighted, sagittal section, infusion of 0.2-mL/kg gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) was performed for all knees at 1, 4, 6, and 12 months after surgery and performed for some knees irregularly thereafter. The signal/noise quotient (SNQ) of grafts was calculated by use of magnetic resonance imaging based on the method of Weiler et al. (2001) as follows: SNQ = (Signal of ACL graft - Signal of quadriceps tendon)/Signal of background. RESULTS: The SNQ of allografts was significantly lower than for autografts 12 months after surgery. As for the SNQ 1 month after surgery, there was no difference before or after Gd-DTPA infusion in the allografts; however, the SNQ was significantly higher after Gd-DTPA infusion in autografts. The SNQ after Gd-DTPA infusion continued to increase until 12 to 24 months in the allograft group but peaked at 4 or 6 months in the autograft group. CONCLUSIONS: Compared with autologous tendons, allogeneic tendons have a slower onset and rate of revascularization. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

[Oral osteoporosis: a review and its dental implications].

In post-menopausal osteoporosis, lack of estrogen will affect the remodeling of the bone tissue in such a way that, in most patients with periodontitis, the amount of bone resorbed exceeds that being formed, resulting in net bone loss. Osteoporosis can be treated by a variety of methods, the hormone replacement therapy (HRT), the selective estrogen receptor modulators (SERM) and the bisphosphonates. The HRT or bisphosphonates treatments improve the clinical outcome of periodontal disease and may be an adjunctive treatment to preserve periodontal bone mass. This paper reviews the current evidence on the mechanism of periodontal breakdown after menopause and the benefit to oral health by treatments for osteoporosis.

[Osteoporosis and periodontal disease in postmenopausal women: association and mechanisms].

Many studies have attempted to define the relationship between postmenopausal osteoporosis and periodontal disease. Most studies support a positive association between these common diseases; however, many are cross-sectional in nature, include relatively small sample sizes, and have inadequate control of potential confounding factors, such as age, gender, hormone intake, race, and smoking, limiting our understanding of the nature of the relationship between these diseases. Clinical conditions causing low estrogen environments in postmenopausal women allow T- and B-cell abnormalities, increased local production of the bone-active cytokines (i.e., Interleukin-1, -6 and -8, tumor necrosis factor [TNF]-alpha) and a rise in prostaglandin E(2), resulting in the progression of periodontitis.

[Osteoporosis and periodontal disease in postmenopausal women].

Many studies have attempted to define the relationship between postmenopausal osteoporosis and periodontal disease. Most studies support a positive association between these common diseases; however, many are cross-sectional in nature, include relatively small sample sizes, and have inadequate control of potential confounding factors, such as age, gender, hormone intake, race, and smoking, limiting our understanding of the nature of the relationship between these diseases. Clinical conditions causing low estrogen environments in postmenopausal women allow increased local production of the bone-active cytokine and the progression of periodontal disease. Prospective studies are needed to confirm or refute a causal relation.