Jun Aikawa

Kitasato University, Edo, Tōkyō, Japan

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Publications (6)2.32 Total impact

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    ABSTRACT: To evaluate the discrepancy between the anatomical axis of the distal femur of Japanese patients and the stem position of 5 types of femoral components. Lateral radiographs of 12 men and 88 women aged 31 to 83 (mean, 59) years with rheumatoid arthritis were evaluated. The discrepancy between the anatomical axis of the distal femur and the stem position of 5 types of femoral components (Nexgen LCCK, Press-Fit Condylar, Scorpio, Total Stabilizer, and Rotating Hinge) was determined by superimposing the template of each model over each lateral radiograph. The anatomical axis varied widely among our patients, as did the stem position of the 5 femoral components. Stems of all 5 femoral components tended to be more posterior than the anatomical axis. The discrepancy was smallest in the Nexgen LCCK, followed by the Press-Fit Condylar components. It was >3 mm in the other 3 models. In 35% of the patients, none of the prosthesis could be placed in an appropriate position. Smaller-size prostheses appear necessary for the Japanese. The stem position should be an important factor guiding selection of the appropriate model. The currently available femoral components may not be appropriate for the Japanese. Prostheses with appropriately positioned stems for Japanese patients with rheumatoid arthritis should be developed.
    Journal of orthopaedic surgery (Hong Kong) 04/2010; 18(1):11-4.
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    ABSTRACT: To compare quality of life, knee function, and physical activity in 33 elderly women with or without early-stage knee osteoarthritis (OA). 33 Japanese elderly women (mean age, 66 years) with (n=18) or without (n=15) early-stage knee OA symptoms (knee pain and decreased range of motion [ROM]) were recruited. The height, weight, and body mass index, disease severity, quality of life (according to the Japanese Knee Osteoarthritis Measure [JKOM]), knee function (knee extension strength, ROM, 10-m gait time), and the amount of physical activity (net energy expenditure and step count) of the 2 groups were compared. The 2 patient groups did not differ significantly with respect to mean patient age, height, and body mass index, except for weight. Regarding knee function, mean knee extension strength, ROM (extension but not flexion), and 10-m gait speed (comfortable and maximum) were significantly inferior in patients with knee OA than in controls. Regarding the mean amount of physical activity undertaken, patients with knee OA did not differ significantly from controls with respect to net energy expenditure (179 vs. 212 Kcal/day) and step count (8016 vs. 9729 steps/day). Net energy expenditure (r= -0.65, p=0.04) and step count (r= -0.62, p=0.02) correlated negatively with JKOM scores in patients with knee OA but not in the controls. In Japanese elderly women with knee OA, quality of life (JKOM scores) correlated negatively with physical activity (net energy expenditure and step count). The 2 groups undertook similar amounts of physical activity, although those with knee OA exhibited less knee extension strength. Decreased knee extension strength coupled with high levels of physical activity may exacerbate the development of knee OA.
    Journal of orthopaedic surgery (Hong Kong) 04/2010; 18(1):31-4.
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    ABSTRACT: Patients who undergo surgical repair of intercondylar eminence fracture may have postoperative problems despite good reduction. We used arthroscopy to evaluate the outcomes after surgery to repair intercondylar eminence fractures. Ten patients (8 men and 2 women; average age at the time of surgery 27.9 +/- 10.0 years, range from 14 to 50 years) with fracture of the tibial intercondylar eminence underwent an arthroscopic reduction and internal fixation with non-absorbable sutures. Preoperative radiological examination showed that there were one Meyer's type-II, eight type-IIIA and one type-IIIB fractures. Clinical symptoms and physical findings for all the patients were evaluated 1 year postoperatively. Radiographic assessment and the Lysholm rating scale were also utilized. Second-look arthroscopy was performed after 1 year when removing the implant. Arthroscopy was used to assess the appearance of the surface of the anterior cruciate ligament (ACL), check for the existence of cyclops and look for interposition of tissue in the lateral and medial joint spaces. One year after the surgery, all ten patients achieved bony union and had negative Lachman and anterior drawer tests. The average Lysholm knee score was 94.5 +/- 7.2 points (range 100-75 points). Arthroscopy showed an irregular surface on the ACL in two of the ten patients, cyclops in two patients, interposition in the lateral joint space in two patients and interposition in the medial joint space in one patient. In the two cases seen with an irregular surface, the ACL was covered with droopy fibrous tissue, but the substance of the ACL was intact. The two patients who had cyclops showed loss of knee extension (5~10 degrees), which was regained by subsequent resection of the cyclops. One patient who had an interposition into the lateral joint space complained of catching, which was released by resection of the interposing tissue. Arthroscopic refixation of the intercondylar eminence fracture provided bony union and a good clinical outcome. Cyclops syndrome is one of the causes of loss of knee extension, and soft tissue in the medial or lateral compartment is one of the causes of catching of knee after surgical repair of intercondylar eminence fracture. Cyclops syndrome, which may occur following ACL reconstruction, is one of the causes of loss of knee extension after surgical repair of intercondylar eminence fracture. In patients who have knee complaints, such as catching and loss of knee extension, a second-look arthroscopy is useful for identifying and correcting the problem.
    Archives of Orthopaedic and Trauma Surgery 12/2007; 127(9):753-7. · 1.36 Impact Factor
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    ABSTRACT: Once articular cartilage is destroyed, the intrinsic reparative ability is poor. Therefore, various techniques have been developed to repair articular defects. Many kinds of scaffolds have been used for cultured chondrocyte transplantation. In this study, we developed a sponge consisting of type II collagen. We investigated the influence of three-dimensional culture on the maintenance of the chondrocyte phenotype and on the redifferentiation of dedifferentiated chondrocytes. Chondrocytes were isolated from the rib cartilage of rats and were cultured in plastic dishes for a week (P0). The cells were then dissociated with trypsin and subcultured for another 2 weeks (P1). Primary isolated chondrocytes were cultured in the type II collagen sponges for 3 weeks (S1). We compared the gene expression of S1 for chondrogenic markers with the expression of P0 and P1 by reverse transcription-polymerase chain reaction (RT-PCR). The cells were then dissociated with trypsin and subcultured for another 2 weeks (P1) and then another 6 weeks (P3). Cells of P1 were subsequently cultured in type II collagen sponges for 4 weeks (P1r). At each time point, gene expression of chondrogenic markers was examined by RT-PCR. Gene expression of COL2A1, COL10A1, and aggrecan in S1 was the same as in P0. Gene expression of COL10A1 and aggrecan in P1r was higher than in P1 and P3. Gene expression of COL1A1, COL2A1, and SOX9 in P1r was lower than in P1 and P3. Gene expression of ALP and osteocalcin in P1r was detected. These results show that culture in type II collagen sponges could maintain the chondrocyte phenotype; however, dedifferentiated chondrocytes differentiated to hypertrophic chondrocytes. These finding suggest that the complex of cells and scaffolds with primary cells was more useful than that with dedifferentiated chondrocytes in laboratory and clinical application.
    Journal of Orthopaedic Science 10/2005; 10(5):521-8. · 0.96 Impact Factor
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    ABSTRACT: Objectives: The aim of this study was to investigate the combined effects of bone allograft and low-intensity pulsed ultrasound (LIPUS) on osteogenesis using a bone allograft model. Methods: Femora and tibiae were harvested from 8 Wistar rats. These long bones were used for bone allografts. Subsequently, two groups were studied. In the bone allograft group, freeze-dried bone was fixed unilaterally to the anterior surface of the femur in 42 Wistar rats. In the sham-operation group, the same procedure was performed but without a bone allograft in 8 rats. The right femora were exposed to LIPUS for 20 minutes per day, beginning the day after surgery and continued until harvest in both groups. X-ray, three-dimensional micro-computed tomography (3D micro-CT) and histological analysis were performed. Results: In the bone allograft group, x-ray, 3D micro-CT, and histology showed that LIPUS promoted intramembranous ossification induced by the bone allograft, and suggested that LIPUS accelerated the differentiation of mesenchymal stem cells in the cambium layer. Conclusions: LIPUS facilitates the osteogenic effect induced by a bone allograft. LIPUS has been successfully used to accelerate fracture healing. Therefore, we anticipate that earlier clinical application of LIPUS treatment to bone allograft may represent a promising approach for accelerating bone healing.
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    ABSTRACT: Objectives: To evaluate the use of antibiotic-impregnated calcium phosphate cement (CPC) for the treatment of infected total knee arthroplasty while retaining the metal components. Methods: Five infected knees in 5 patients (2 rheumatoid arthritis, 3 osteoarthritis; average age 71 years) were examined after an average postoperative follow-up period of 45 months. The causal bacteria were methicillin-sensitive Staphylococcus aureus in 1 case, Staphylococcus sp. in 2, Staphylococcus epidermidis in 1, and Streptococcus agalactiae in 1. Arthrotomy and anterior capsulectomy was performed. Infected bone lesions identified on radiographs and computed tomography were thoroughly removed by curettage. Bone defects caused by curettage were subsequently filled with antibiotic-impregnated CPC to allow retention of the metal components. Results: Retention of the metal components was made possible when the infection subsided in 4 of the 5 cases. The Japanese Orthopaedic Association scores used to evaluate treatment were comparable before and after treatment in those 4 cases but not the one in which infection was not controlled by antibiotic treatment. Conclusion: Arthrotomy, anterior capsulectomy, thorough debridement with curettage of any infected osseous lesion, and filling the defect with antibiotic-impregnated CPC allowing retention of the metal components proved to be a useful treatment for infected total knee arthroplasty.