This study aimed to evaluate the histological and mechanical features of tendon healing in a rabbit model with second-harmonic-generation (SHG) imaging and tensile testing. A total of eight male Japanese white rabbits were used for this study. The flexor digitorum tendons in their right leg were sharply transected, and then were repaired by intratendinous stitching. At four weeks post-operatively, the rabbits were killed and the flexor digitorum tendons in both right and left legs were excised and used as specimens for tendon healing (n = 8) and control (n = 8), respectively. Each specimen was examined by SHG imaging, followed by tensile testing, and the results of the two testing modalities were assessed for correlation.Objectives
Materials and Methods
Computed tomography based three-dimensional surgical preoperative planning (3D-planning) has been expanded to achieve more precise placement of knee and hip arthroplasties. However, few reports have addressed the utility of 3D-planning for the total elbow arthroplasty (TEA). The purpose of this study was to assess the reliability and precision of 3D planning in unlinked TEA. Between April 2012 and April 2014, 17 joints in 17 patients (male 4, female 13) were included in this study. Sixteen patients were rheumatoid arthritis and one was osteoarthritis and the average age at the time of the procedure was 61 years (range 28–88). Unlinked K-NOW total elbow system (Teijin-Nakashima Medical. Co. Ltd.) was used in all cases and 3D planning was performed by Zed View (Lexi.Co.). After the appropriate size and position of the prosthesis were decided on the 3D images [Figure 1], the position of the bone tunnel made for the insertion of humeral and ulnar stem was recorded on axial, sagittal, and coronal plane (4 point measurements for humerus, and 6 points for ulna, See Figure 2). After the elbow was exposed via a posterior approach, bone resection and reaming was performed according to the 3D planning. The surgeon took an appropriate adjustment to align the prosthesis properly during the surgery. The final position of the stem insertion was recorded immediately prior to set the prostheses. We analyzed the accuracy of stem size prediction, the correlation between preoperative and final measurements, and postoperative complications.Objective
Methods
For anatomical reconstruction in shoulder arthroplasty, it is important to understand normal glenohumeral geometry. Unfortunately, however, the details of the glenohumeral joint in Asian populations have not been sufficiently evaluated. There is a racial difference in body size, and this difference probably results in a difference in glenohumeral size. The purpose of this study was to evaluate three-dimensional geometry of the glenohumeral joint in the normal Asian population and to clarify its morphologic features. Anthropometric analysis of the glenohumeral joint was performed using computed tomography scans of 160 normal shoulders from healthy volunteers in age from 20 to 40 years. Using OsiriX MD, Geomagic Studio, and AVIZO software, the dimensions of humeral head width, humeral head diameter, glenoid height, glenoid width, and glenoid diameter were analyzed three-dimensionally (Figure 1). In diameter analyses, the humeral head was assumed to be a sphere and the glenoid was to fit a sphere (Figure 2–3). Sex differences in height, humeral length, humeral head width, humeral head diameter, glenoid height, glenoid width, and glenoid diameter were compared using Mann-Whitney U tests. The correlations between sides and among the respective parameters in the glenohumeral dimensions were evaluated with Spearman rank correlation tests. The significance level was set at 0.05 for all analyses.Introduction
Methods
Mesenchymal stem cells (MSCs) are identified by having the ability to differentiate into various tissues and typically used to generate bone tissue by a process of resembling intramembranous ossification, namely by direct osteoblastic differentiation. However, most bones develop by endochondral ossification, namely via remodeling of hypertrophic cartilaginous templates. To date, reconstruction of bone defects by endochondral ossification using mesenchymal stem cell-derived chondrocytes (MSC-DCs) have not been reported. The purpose of this study was to evaluate the effects of the transplantation of MSC-DCs on bone healing in segmental defects in rat femurs. Segmental bone defects (5, 10, 15-millimeter) were produced in the mid-shaft of the femur of the Fisher 344 rats and stabilised with an external fixator. Bone marrow was aspirated from the rat's femur and tibia at 4 weeks before operation. MSCs were isolated and grown in culture and seeded on a Poly dl-lactic-co glycolic acid (PLGA) scaffold. Subsequently, the scaffold was cultured using chondrogenic inducing medium for 21 days. The characteristics of the PLGA scaffold are radiolucent and to be absorbed in about 4 months. The Treatment Group received MSC-DCs, seeded on a PLGA scaffold, locally at the site of the bone defect, and Control Group received scaffold only. The healing processes were monitored radiographically and studied biomechanically and histologically.Introduction
Methods
The purpose of this study was to evaluate the effects of implantation of mesenchymal stem cell derived condrogenic cells (MSC-DC) on bone healing in segmental defects in rat femur. Five-millimeter segmental bone defects were produced in the mid-shaft of the femur of Fisher 344 rats and stabilized with external fixator. The Treatment Group received MSC-DC, seeded on a PLGA scaffold, locally at the site of the bone defect, and Control Group received scaffold only. The healing processes were monitored radiographically (Softex), and studied radiographically (Micro-CT) and histologically.Purpose
Methods
what size of defect is optimal for creating an atrophic nonunion animal model has not been well defined. Our aim in this study was to establish a clinically relevant model of atrophic nonunion in rat femur by creation of a bone defect to research fracture healing and nonunion. We used 30 male Fischer 344 rats (aged 10–11 weeks), which were equally divided into six groups. The segmental bone defects to a single femur in each rat were performed by double transverse osteotomy, and different sized defects were created by group for each group (1 mm, 2 mm, 3 mm, 4 mm, 5 mm and 6 mm). The defects were measured and maintained strictly by using an original external fixator. The periosteum for each defect was stripped both proximally and distally. Thereafter, these models were evaluated by radiology and histology. Radiographs were taken at baseline and at intervals of two weeks over a period of 8 weeks. Atrophic nonunion was defined as a lack of continuity and atrophy of both defect ends radiologically and histologically at eight weeks.Introduction
Materials and methods
Reconstruction of 10mm segmental bone defects in rat by mesenchymal stem cell derived chondrogenic cells (MSC-DC) Mesenchymal stem cell derived condrogenic cells (MSC-DC) have excellent potential for healing 5 mm bone defect in rat femur. To evaluate the effectiveness of MSC-DC on bone healing in 10 mm segmental bone defects in rat femur.Background
Purpose
We used the D-dimer level as a measure for the early diagnosis of deep vein thrombosis (DVT), which can cause fatal pulmonary thromboembolism (PTE), following total hip arthroplasty (THA). Recently, we have performed anticoagulation therapy, in addition to the use of elastic stocking and intermittent pneumatic compression, for the prevention of DVT. In the present study, we examined the effect of administration of anticoagulation drugs on the changes in the D-dimer level. Of 123 patients who had undergone THA between April 2003 and October 2007, 70 patients who were available for 3 or more measurements of the D-dimer level were included in this study. These 70 patients were divided into the following three groups: N group consisting of 30 patients who were not given anticoagulation drugs (4 males, 26 females; mean age 69 years (45–87 years); mean body mass index (BMI) 24.1 (15.8–28.5)), W group consisting of 23 patients who were administered dose-adjusted warfarin at a dose of 5 mg within 3 days after surgery and at 1–3 mg following 1-day rest (3 males, 20 females; mean age 62 years (48–83 years); mean BMI 24.1 (17.8–35.9)), and F group composed of 15 patients who were given fondaparinux (2.5 mg) between postoperative days 1 and 14 (6 males, 11 females; mean age 64 years (51–81 years); mean BMI 23.1 (18.2–31.6)). There was no significant difference in sex ratio and BMI between the three groups, while a significant difference in age was found between the N and F groups. The D-dimer level was measured on days 3, 7, 10, 14 and 21 and changes in the median D-dimer level were compared between groups. In the N group, the D-dimer level was around 8 μg/ml between postoperative days 3 and 10 and exceeded 10 μg/ml on postoperative day 14. In the W group, the D-dimer level was around 8 μg/ml between postoperative days 3 and 14 and decreased thereafter. In the F group, the D-dimer level was less than 3 μg/ ml on postoperative day 3, increased gradually thereafter until postoperative day 14, reaching the maximum level of approximately 8 μg/ml, and then decreased thereafter. The D-dimer level was significantly different between the N and F groups and between the W and F groups on day 3, between the N and F groups and between the W and F groups on day 7, and between the N and W groups on day 21. With regard to hemorrhagic adverse events, neither major nor minor bleeding event was observed in either the W or F group. The present study suggested that fondaparinux is effective for preventing DVT in an early postoperative period, with relatively low D-dimer levels observed between postoperative days 3 and 10. We expect that various types of anticoagulation drugs will be used in the future. Elucidating the effect of these drugs on the D-dimer level will help in the early diagnosis of DVT.
The primary fixation of cementless hip prostheses is related to the shape of the stem. When there is a complication of loading in several directions, the mechanical fixation of a hip stem is considered to provide good primary fixation. The purpose of this study was to evaluate whether the IMC stem with its characteristic fixation method, which was developed by a group at Kitasato University, contributes to primary fixation by finite element analysis. Analysis was performed at a friction coefficient of 0.1 with automatic contact, under the restriction of the distal femoral end. The following three loading conditions were applied:
step loading of the joint resultant force in the region around the hip stem, loading in the rotational direction, simulating torsion, and loading of the femoral head equivalent to that during walking. Micromotion of the IMC stem along the x-, y-, and z-axes direction was calculated by simulation, and the stress distributed on the stem and femur was determined. Micromotion along the z-axis, which is a clinical problem in hip prosthesis stems, was lower in the IMC stem than in other stems reported. Micromotion of the stem along the z-axis was low, indicating a low risk of sinking. The interlocking mechanism, which is a characteristic of the IMC stem, functioned to suppress its micromotion, indicating that the locking method of this stem contributed to the stability. Since no stress concentration was detected, it was considered that there are no risks of breakage of the IMC stem and femur. It was suggested that effective fixation of the finite element model of the IMC stem can be achieved because the micromotion and stress level are appropriate for primary fixation.
At the revision surgery of the cemented Total hip arthroplasty (THA), complete removal of an old cement mantle of the femur without loosening is very difficult. It can be associated with complications, such as femoral fracture, perforation and femoral bone loss. Cement-within-cement technique (CWCT) of femoral revision is very useful and advantageous without those complications for special cases. We reviewed the experiential radiological outcomes using CWCT for the cemented femoral revision. Between 1999 and 2006, we performed seventeen of revision THA using CWCT in 17 patients. There were four men and 13 women, with an average age of 75 years (range 68 to 87), with an average follow up of 39 months (range 12 to 87). The reasons for revision surgery were eleven for cup loosening, 5 for recurrent dislocation and one technical failure of stem insertion intra-operatively. An original Charnley stem (Depuy, Leeds, England) was implanted in six cases, an Exeter femoral component (Stryker Benoist Girard, Herouville, Saint-Clair, France) was in 10 and another stem in one. Posterolateral approach without trochanteric osteotmy was performing for all patients. After the femoral component was removed, the cement mantle was examined in detail, to confirm cement-bone interface and cement fracture. The cement mantle was washed with a pulsatile lavage to clean and to be dried. If necessary, the surface of the cement mantle was reamed. A double mix of Simplex P cement (Stryker Limerick, Limerick, Ireland) in liquid phase was inserted within the cement mantle by a cement gun with a thin nozzle(Stryker Instruments Kalamazoo, US). Thereafter suction and pressuriser were used, and a femoral component was inserted. The results of this study were that the intra-operative complication was two fractures of the greater trochanter at the stem removed and was one shaft perforation at a new original Charnley stem inserted. The stem position was one valgus and 3 varus stem position of more than 2 degrees. Radiographic outcomes showed no stem loosening, no radiolucent line at the bone-cement interface, nor any osteolysis in the patients at final follow-up. We conclude that this cement-within-cement technique is good radiographic outcomes up to 87 months and this technique should be used with the thinner femoral component than the previous.
