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Biomedical subjects

Hiroshige Sakai

Publications and source records attributed to Hiroshige Sakai.

8 recordsLinked to original sources

Rapid chondrolysis after arthroscopic partial lateral meniscectomy in athletes: a case report.

We present a patient with a severe chondrolysis after arthroscopic partial lateral meniscectomy in a 17-year-old high school basketball player. This is a rare but severe complication after arthroscopic partial lateral meniscectomy. At 7 months after the first operation, a second-look arthroscopy showed numerous cartilaginous debris floating in the knee and a high-grade cartilage damage on the lateral compartment of the tibia. This unexpected complication and a consideration of its etiology are shown.

Adolescent↗

The use of newly developed real-time PCR for the rapid identification of bacteria in culture-negative osteomyelitis.

We report a case of a culture-negative osteomyelitis in which our newly developed real-time polymerase chain reaction (PCR) could differentiate Staphylococcus aureus from Staphylococcus epidermidis. This is the first report that described the application of this novel assay to an orthopedics clinical sample. This assay may be useful for other clinical culture-negative cases in a combination with a broad-spectrum assay as a rapid microorganism identification method.

Bacteriological Techniques↗

The structural properties of an osteochondral cylinder graft-recipient construct on autologous osteochondral transplantation.

PURPOSE: The purpose of this study was to investigate the changes in structural properties of an osteochondral cylinder graft-recipient construct after autologous osteochondral transplantation. METHODS: A full-thickness cylindrical osteochondral defect (5 mm in diameter and 3 mm in depth) was made on the femoral condyle of a mature female Japanese white rabbit using the Osteochondral Autograft Transfer System (OATS; Arthrex, Naples, FL). The defect was repaired with an osteochondral plug (6 mm in diameter and 3 mm in depth) taken from the contralateral femoral condyle using the OATS. The implanted osteochondral grafts were evaluated immediately after surgery and at postoperative weeks 1, 3, 8, and 12. The stiffness of articular cartilage was analyzed using a tactile sensor system (AXIOM, Fukushima, Japan), which measures stiffness based on changes in resonance frequency when a vibrating tactile sensor touches articular cartilage. The specimens were stained with hematoxylin and eosin and serial sections were examined microscopically. RESULTS: The cartilage stiffness of the graft immediately after surgery was 107,695.1 N/m, which was not statistically different from the normal cartilage stiffness (100,027.5 N/m). The stiffness at postoperative weeks 1, 3, 8, and 12 was 95,386.8, 92,899.3, 95,969.8, and 104,683.7 N/m, respectively. The stiffness at postoperative weeks 1, 3, and 8 was significantly lower than the normal cartilage stiffness and the stiffness at postoperative week 12 was the same as normal cartilage. A new bone formation with an increase of bone trabeculae between the osteochondral cylinder graft and the recipient was observed at postoperative weeks 1, 3, and 8. Thereafter, at postoperative week 12, bone trabeculae decreased to the same level as observed in a normal model due to the progress of bone remodeling. CONCLUSIONS: The stiffness of articular cartilage of the osteochondral graft was normal at the time the graft was initially placed and at postoperative week 12. However, the stiffness at postoperative weeks 1, 3, and 8 was lower than the normal cartilage stiffness. CLINICAL RELEVANCE: Care should be taken when planning the rehabilitation program at an early phase after osteochondral transplantation.

Animals↗

A molecular gram stain using broad range PCR and pyrosequencing technology: a potentially useful tool for diagnosing orthopaedic infections.

The bacteria associated with orthopaedic infections are usually common gram-positive and gram-negative bacteria. This fundamental grouping of bacteria is a necessary first step in the selection of appropriate antibiotics. Since polymerase chain reaction (PCR) is more rapid and may be more sensitive than culture, we developed a postamplification pyrosequencing method to subcategorize bacteria based on a few nucleotide polymorphisms in the 16S rRNA gene. We validated this method using well-characterized strains of bacteria and applied it to specimens from spinal surgery cases with suspected infections. Lysates of 114 bacteria including 75 species were created following standard cultivation to obtain DNA. The DNA was amplified by a broad-range real-time PCR. The amplicons were evaluated by pyrosequencing and were classified as gram-positive, gram-negative, or acid-fast bacilli based on the first three to five nucleotides sequenced. In addition, clinical cases of suspected infection were obtained from spinal surgery. The results of the "molecular Gram stain" were compared with the results of traditional Gram stain and culture. The lysates of 107 (93.9%) of the bacteria extracts tested were appropriately categorized as gram-positive and gram-negative or as acid-fast bacilli on the basis of this assay. The sensitivity and specificity of this assay were 100% and 97.4% for gram-positive and 88.3% and 100% for gram-negative isolates. All of the five clinical samples were appropriately categorized as containing gram-positive or gram-negative bacteria with this assay. This study demonstrates that high sensitivity and specificity of a molecular gram stain may be achieved using broad-range real-time PCR and pyrosequencing.

Bacterial Infections↗

Lumbar intervertebral body fusion cages: histological evaluation of clinically failed cages retrieved from humans.

BACKGROUND: Although interbody cages are widely used, there is little histological documentation of the tissue within cages in the human spine. The purpose of this study was to describe the contents of retrieved, clinically failed, interbody cages from human patients, with special reference to the influence of graft type on the viability of bone in the cages. METHODS: Seventy-eight cages that had been retrieved from forty-eight patients were analyzed. There were eight carbon-fiber cages and seventy threaded metal cages. Of the sixty-seven cages for which information about grafting was available, fifty-six had been packed with autograft only, six had local autograft mixed with demineralized bone matrix, four had allograft, and one had demineralized bone matrix only. The indications for cage retrieval included a failed fusion, malposition or migration of the cage, trauma (a compression fracture at the fusion site), low-back pain, progressive spondylosis, nerve-root impingement, and/or infection. The cages had been in situ for an average of twenty-two months. Undecalcified sections through the center of each plastic embedded cage were reviewed, and the approximate areas occupied by viable bone, necrotic bone, fibrocartilage, hyaline cartilage, fibrous tissue, and graft substitute were visually estimated. Debris particles were estimated by a semiquantitative scoring system. RESULTS: Seventy-one of the seventy-eight cages showed evidence of vascular ingrowth and areas of histologically viable bone, representing incorporating bone graft. The average area occupied by viable bone was 44% (range, 0% to 80%). In some cages, relatively large fragments of cortical bone graft were associated with only minimal new-bone formation. Fibrocartilage occupied up to 50% of the available area in these failed cages. Some cages also contained small fibrocartilage seams connecting segments of bone in a pattern that suggested motion in vivo. In thirty-one of the seventy-eight cages, > or = 5% of the available area was occupied by hyaline cartilage, probably from vertebral end plates or facet joints. CONCLUSIONS: While this study was not designed to test the efficacy of cages or of bone graft, the prevalence of hyaline and fibrocartilage in these failed cages illustrates the importance of graft and graft-site preparation to maximize bone-graft incorporation. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Adult↗

MRI-negative rotator cuff tears.

We report two cases of rotator cuff tear in which the T(2)-weighted MRI signal was negative at the first examination, but positive by the second examination without any changes in symptoms. Many authors have reported on correlations between the MRI and operative findings of rotator cuff tears. However, MRI findings, history of symptoms and operative findings in our patients suggest that there was a discrepancy between symptoms and MRI findings dependent on the period from the injury. Operative findings also indicate that intratendinous tears might have occurred first in these patients then progressed to partial or full thickness tears over time. We concluded that physicians should keep rotator cuff pathology in mind even in patients whose MRI findings are negative but symptoms of rotator cuff tear persist.

Adult↗

Avulsion fracture of the posterior oblique ligament associated with acute tear of the medial collateral ligament.

The term posterior oblique ligament was proposed in 1973 but the specific anatomy of this region has been controversial. It has been concluded that the posterior oblique ligament is separated from the medial collateral ligament, each with distinctly different bony attachment points. In this article, we report a posterior oblique ligament avulsion fracture associated with a medial collateral ligament rupture.

Accidents, Traffic↗