The effect of administration of double stranded MicroRNA-210 on acceleration of Achilles tendon healing in a rat model.

BACKGROUND: Achilles tendons heal slower than other tissues, therefore requiring the developmnent of a strategy for accelerating the process. Vascular supply plays an important role in primary tendon healing, especially during the early healing phase. MicroRNA (miR)-210 has been reported as being crucial for angiogenesis, which is a key factor of tissue repair. We report herein that local injection of synthetic miR-210 into the injured Achilles tendon of a rat accelerated healing of the tendon. METHODS: Achilles tendons were transected and repaired via the Kessler suture technique in Sprague-Dawley rats. Then, double stranded (ds) miR-210 was injected into the repaired sites. The control group was injected with non-functioned dsRNA. At 2, 6 and 12 weeks, histological evaluations were performed. At two and six weeks, mechanical testing and angiogenesis were evaluated. Gene expression analysis using real-time polymerase chain reaction (PCR) and immunohistochemistry were performed at two weeks. RESULT: At two and six weeks, regular dense collagen tissue in the miR-210 group was observed and the diameter of collagen fiber in the miR-210 group was significantly higher than in the control. At two weeks, the ultimate failure load was significantly higher than in the control group, and expression of VEGF, FGF2 and type I collagen was upregulated. Abundant vessels in the miR-210 group were observed at two weeks, but there was no significant difference in vessel numbers between the two groups at six weeks. At 12 weeks, repaired Achilles tendons in the miR-210 group consisted of parallel and dense fibers, whereas wavy and loose fibers were still observed in the control group. CONCLUSION: The current study showed that single local injection of synthetic miR-210 promotes Achilles tendon healing in the early phase.

The clinical and radiographic results of intertrochanteric curved varus osteotomy for idiopathic osteonecrosis of the femoral head.

PURPOSE: In this study, postoperative results of intertrochanteric curved varus osteotomy (CVO) for idiopathic osteonecrosis of the femoral head (ION) were studied retrospectively and optimal indication of CVO was considered. METHODS: Between 1995 and 2011, CVO was performed in 51 patients (53 hips) for the treatment of ION in our department. The patients who had the potential to obtain acetabular coverage of more than one-third of the intact articular surface on pre-operative AP hip radiographs in maximum abduction were considered suitable for this operation. For radiological assessment, a ratio of necrotic volume, a ratio of postoperative intact surface on the weight-bearing area, progression of collapse, shortening length of the lower limb, and lateralization of great trochanter were evaluated. RESULTS: The mean ratio of necrotic volume was 16.9 %. The mean ratio of postoperative intact surface on the weight-bearing area of the femoral head was 51.7 %. The progression of collapse was observed in two hips (ratio of necrotic volume 10.4, 39.8 %; ratio of postoperative intact area 36.5, 38.1 %). The mean shortening length of the lower limb was 9 mm, and the mean lateralization of great trochanter was 3 mm. One hip (ratio of necrotic volume 11.6 %, ratio of intact area 35.8 %) was converted to THA because of the progression of osteoarthritis at 55 months after CVO. CONCLUSION: The results of CVO for ION were successful, if this procedure was indicated for cases with intact load-bearing area more than 40 %.

Treatment of cartilage defects by subchondral drilling combined with covering with atelocollagen membrane induces osteogenesis in a rat model.

BACKGROUND: The coverage of the atelocollagen membrane at the chondral defect after subchondral drilling might improve the beneficial effects for cartilage repair because of the prevention of scattering and accumulation of cells and growth factors from bone marrow within the chondral defect. On the other hand, it might block cells and factors derived from the synovium or cause high pressure in the chondral defect, resulting in prevention of cells and growth factors gushing out from the bone marrow, which leads to disadvantages for cartilage repair. METHOD: We tested this hypothesis in a 2-mm-diameter chondral defect created in the articular cartilage of the patellar groove in a rat models. Defects were left untreated, or were drilled or drilled and covered with an atelocollagen membrane; healing was evaluated by histology and gene expression analysis using real-time polymerase chain reaction and immunohistochemistry. RESULTS: Membrane coverage induced bone tissue ingrowth into the punched chondral defect. At 1 week, expression of TGFß, Sox9, Runx2, osteocalcin, Col1a1, and Col2a1 in the drilling group was significantly higher than in the covering group. At 4 weeks, expressions of TGFß, Runx2, and Col1a1 were all significantly higher in the drilling group, while Sox9, osteocalcin, and Col2a1 were significantly higher in the covering group. Immunohistochemistry demonstrated Sox9, osteocalcin, and type II collagen on the bony reparative tissue in the covering group. CONCLUSIONS: These results suggest that the atelocollagen membrane coverage resulted in inhibition of cartilage repair.

Ten year results of transtrochanteric valgus osteotomy with or without the shelf procedure.

PURPOSE: The purpose of this study was to examine retrospectively the effectiveness of Sugioka's transtrochanteric valgus osteotomy (TVO) combined with the shelf procedure for patients who had advanced osteoarthritis (OA) of the hip with severe acetabular dysplasia. METHODS: Sixty-two hips in 61 patients were reviewed retrospectively between April 1993 and March 2009. Of these hips, 25 hips with the pre-operative acetabular head index (AHI) ≥ 60 % (single group) underwent a TVO, whereas the other 37 with AHI < 60 % (combined group) underwent a TVO combined with the shelf procedure. RESULTS: Using conversion to total hip arthroplasty as the endpoint, the Kaplan-Meier survival rates at ten years were calculated to be 85.5 % for the single group and 100 % for the combined group; there was a significant difference between the two groups (p < 0.05, log-rank test). Similarly, calculated using progressive OA as the endpoint, survival rates at ten years were 69.5 % and 89.3 % respectively; there was also a significant difference between the two groups (p < 0.05, log-rank test). In the single group, the latest radiographic evaluations of the patients with the pre-operative AHI ≥ 70 % were significantly better than those of the patients with the pre-operative AHI < 70 % (P < 0.05). CONCLUSION: More satisfactory ten year results of TVO were obtained in cases that had a pre-operative AHI of ≥70 %, or where the shelf procedure was added. It is desirable that acetabuloplasty be added for patients with pre-operative AHI < 70 %.

Bony impingement depends on the bone morphology of the hip after total hip arthroplasty.

PURPOSE: The purpose of this study was to evaluate whether the bone morphology of the hip affects the range of motion (ROM) in total hip arthroplasty (THA). METHODS: Using the CT data of 63 patients who underwent THA, we calculated the ROM of flexion (Flex), internal rotation (Int-R) and external rotation (Ext-R) using 3D dynamic analysis software. We measured the distance between the anterior surface of the stem and anterior aspect of the greater trochanter (GTa length) at the cutting point and between the tip of the antero-inferior iliac spine (AIIS) and coronal plane of both femoral heads (AIIS length), as a parameter of the femur and pelvis, respectively. The relationship between the ROM, bone anatomy and impingement site was evaluated. RESULTS: We found a significant decrease in the ROM of Flex and the Int-R to be inversely proportional to the GTa and AIIS length. In Flex and Int-R, the anterior intertrochanteric region often impinges on the AIIS in patients with larger bone anatomy. CONCLUSIONS: We demonstrated that the bone morphology of the hip substantially affects the ROM of Flex and Int-R, especially in patients with large bone anatomy. For these patients we should consider bony impingement in THA.

Acceleration of healing of the medial collateral ligament of the knee by local administration of synthetic microRNA-210 in a rat model.

BACKGROUND: Injury to the medial collateral ligament (MCL) of the knee joint is the most common ligament injury of the knee. Ligament healing generally takes a long time. Micro-ribonucleic acid (miRNA) is one of the noncoding RNAs and plays a crucial role in physiological function; miRNA (miR)-210 is known as a potent factor of angiogenesis, which is an important initiator of ligament healing. The purpose of this study is to examine the effect of local injection of double-stranded (ds) miR-210 on the healing of the MCL of rat knee joint. METHODS: MCLs of Sprague-Dawley rats were cut transversely. After the fascia and skin were sutured, dsmiR-210 or control dsRNA was injected into the injured site of MCL. At 2 weeks and 4 weeks, histological analysis and immunofluorescence staining of vascular endothelial growth factor, isolectin B4, collagen type 1, and Ki67 as well as a mechanical test were performed. Analysis of complementary deoxyribonucleic acid (cDNA) microarray data was performed at 1 week. RESULTS: Histological analysis showed that parallel fibres in the injured site were organised at 2 weeks and became thicker at 4 weeks in the miR-210-treated group, whereas the injured site in controls was filled with loose fibrous tissues and was thinner than that in the miR-210-treated group. The number of blood vessels in the miR-210-treated group was significantly higher than that in controls (p < 0.05), and vascular endothelial growth factor, Ki67, and collagen type 1 in the miR-210-treated group were intensely expressed in the repaired site as compared to the control group. The mechanical test indicated that the ultimate failure load in the miR-210-treated group was significantly higher than that in the control group at 2 weeks. The cDNA microarray analysis showed significant upregulation of genes related to cell proliferation and cell differentiation, and genes involved in negative regulation of apoptosis. CONCLUSION: This study showed that local injection of dsmiR-210 could accelerate MCL healing in rat, which is likely due to stimulation of angiogenesis at the healing site.

Repair mechanism of osteochondral defect promoted by bioengineered chondrocyte sheet.

Cell sheet engineering has developed as a remarkable method for cell transplantation. In the field of cartilage regeneration, several studies previously reported that cartilage defects could be regenerated by transplantation of a chondrocyte sheet using cell sheet engineering. However, it remains unclear how such a thin cell sheet could repair a deep cartilage defect. We, therefore, focused on the mechanism of cartilage repair using cell sheet engineering in this study. Chondrocyte sheets and synovial cell sheets were fabricated using cell sheet engineering, and these allogenic cell sheets were transplanted to cover an osteochondral defect in a rat model. Macroscopic and histological evaluation was performed at 4 and 12 weeks after transplantation. Analysis of the gene expression of each cell sheet and of the regenerated tissue at 1 week after transplantation was performed. In addition, green fluorescent protein (GFP) transgenic rats were used as donors (transplanted chondrocyte sheets) or recipients (osteochondral defect models) to identify the cell origin of regenerated cartilage. Cartilage repair was significantly better in the group implanted with a chondrocyte sheet than in that with a synovial cell sheet. The results of gene expression analysis suggest that the possible factor contributing to cartilage repair might be TGFß1. Cell tracking experiments using GFP transgenic rats showed that the regenerated cartilage was largely composed of cells derived from the transplanted chondrocyte sheets.

The Cementless Spotorno stem in THA: 10 year results.

BACKGROUND: The clinical results of total hip arthroplasty (THA) with a cementless prosthesis have been constantly improving due to progress in the area of stem design and surface finish. Cementless Spotorno stem (CLS stem; Zimmer, Warsaw, USA) is a double-tapered rectangular straight stem. The purpose of this study is to investigate the mean 10 year results of CLS stem and to evaluate the press-fit stability of CLS stem. METHODS: One hundred and eighty-six consecutive patients (194 hips) were evaluated at more than five years after THA using CLS stems. The mean follow-up period was 111 months. The radiographic stability of the femoral stem was determined by Engh's criteria. The ascertained period of spot welds was noted by Gruen zones on the femoral side. The presence of stress shielding, and subsidence was also evaluated. RESULTS: A stable stem with bony on growth was identified in all cases. The mean period of expression of spot welds was 10.8 months in zone 2, 9.9 months in zone 3, 8.5 months in zone 5, and 8.8 months in zone 6. Stress shielding of more than grade 2 was observed in only three hips, which was non-progressive at one year after surgery. Subsidence of more than 2 mm was not observed in any of the hips. CONCLUSIONS: Excellent stability of CLS stem has been maintained without abnormal bone reaction at the proximal femur. CLS stem is considered to achieve not only press-fit stability at trochanteric and subtrochanteric level, but bony fixation by osseointegration within one year after THA.

T2 Mapping Magnetic Resonance Imaging Encourages an Arthroscopic Approach for Osteoid Osteoma in the Acetabulum.

Intra-articular osteoid osteoma (OO) is uncommon, especially in the hip joint. Delayed treatment may cause early osteoarthritis; however, diagnosis and complete excision are often challenging. We describe the feasibility of the combination of T2 mapping magnetic resonance imaging evaluation and arthroscopic excision of OO in the acetabulum. A 12-year-old boy presented with a 6-month history of hip pain. An undifferentiated tumor of the medial wall of the acetabulum was suspected on radiographs and computed tomography. T2 mapping showed joint effusion, and the T2 value of the acetabular cartilage just above the tumor was significantly high. These findings suggested OO in the acetabulum. An arthroscopic excision was performed for biopsy and excision of the tumor to avoid damage to the normal cartilage and growth plate. Histologic examination confirmed the OO. At 16 months' follow-up, there was no evidence of recurrence. This is the first report to evaluate intra-articular OO by T2 mapping and to treat it arthroscopically. Arthroscopic treatment assisted by T2 mapping has excellent potential as a minimally invasive technique to enable us to approach the tumor from the area of discriminative abnormal cartilage with minimal damage to the normal cartilage and surrounding tissue.

Intra-articular injection of synthetic microRNA-210 accelerates avascular meniscal healing in rat medial meniscal injured model.

INTRODUCTION: The important functions of the meniscus are shock absorption, passive stabilization and load transmission of the knee. Because of the avascularity of two-thirds of the meniscal center region, the treatment of tears in this area is hard. Recently, microRNAs have been proven to play an important role in the pathogenesis of diseases. We focused on microRNA (miR)-210, which plays a wide spectrum of roles comprising mitochondrial metabolism, angiogenesis, DNA repair and cell survival. This study aimed to investigate the effect of intra-articular injection of synthetic miR-210 on the injured meniscus in the avascular zone. METHODS: The middle segments of the medial meniscus of Spraque Dawley rats were incised longitudinally with a scalpel. An intra-articular injection of double-stranded (ds) miR-210 (for control group using control dsRNA) with atelocollagen was administered immediately after injury. Four weeks and 12 weeks after the injection, we conducted a histologic evaluation, immunohistochemical evaluation and Real-time PCR analysis. In vitro, the inner meniscus and synovial cells were isolated from rat knee joint, and were transfected with ds miR-210 or control dsRNA. Real-time PCR and immunohistochemical evaluations were performed. RESULTS: Twenty-four hours after the injection, FAM (Fluorescein amidite) labeled miR-210 was observed in the cells around the injured site. Four weeks after the injection, the injured site of the miR-210 group was filled with repaired tissue while that of the control was not repaired. In gene expression analysis of the meniscus, the expression of miR-210, Collagen type 2 alpha 1 (Col2a1), Vascular endothelial growth factor (VEGF), and Fibroblast growth factor-2 (FGF2) in the miR-210 group was significantly higher than that in the control. At 12 weeks, the intra-articular injection of miR-210 had healed the injured site of the meniscus and had prevented articular cartilage degeneration. In vitro, miR-210 upregulated Col2a1 expression in the meniscus cells and VEGF and FGF2 expression in the synovial cells. CONCLUSIONS: An intra-articular injection of ds miR-210 was effective in the healing of the damaged white zone meniscus through promotion of the collagen type 2 production from meniscus cells and through upregulated of VEGF and FGF2 from synovial cells.