Enhancement of muscle repair using human mesenchymal stem cells with a magnetic targeting system in a subchronic muscle injury model.

BACKGROUND: A magnetic cell targeting system was previously developed to promote the accumulation of transplanted cells in sites of injury in order to effectively treat injured tissues. However, the optimum time of exposure to the magnetic field and the strength of the magnetic force have not yet been clarified. In this study, we investigated the optimum conditions of the magnetic force required to retain iron-labeled human mesenchymal stem cells (hMSCs) at the site of transplantation for muscle repair in a subchronic skeletal muscle injury nude rat model. METHODS: First, the optimum strength and time of exposure to the magnetic force for cell retention at the transplantation site were investigated 2 days after cell transplantation (1 × 10(5) cells). Second, the degree of enhancement of muscle repair was investigated at 3 weeks after cell transplantation in the group treated without a magnetic force and two typical magnetic condition groups that exhibited different levels of cell integration in first part of the study. RESULTS: On the basis of the results of the first investigation, it was concluded that a magnetic strength of 1.5 T and 10 min of exposure to the magnetic force were efficient conditions to induce the retention of transplanted cells at the site of transplantation. In the second study, the groups exposed to a 1.5-T magnetic field for 10 min demonstrated significant enhancement of muscle repair, both histologically and electromechanically. CONCLUSIONS: This study identified the optimal conditions required to retain transplanted hMSCs at the site of transplantation using a magnetic targeting system. This study also showed that the restoration of subchronic muscle injuries can be enhanced by magnetically labeled hMSCs following the application of a magnetic force.

A 30-year follow-up study of rotational acetabular osteotomy for pre- and early-stage osteoarthritis secondary to dysplasia of the hip.

Aims: The objective of this study was to present the outcomes of rotational acetabular osteotomy (RAO) over a 30-year period for osteoarthritis (OA) secondary to dysplasia of the hip in pre- or early-stage OA. Methods: Between September 1987 and December 1994, we provided treatment to 47 patients (55 hips) with RAO for the management of pre- or early-stage OA due to developmental hip dysplasia. Of those, eight patients (11 hips) with pre-OA (follow-up rate 79%) and 27 patients (32 hips) with early-stage OA (follow-up rate 78%), totalling 35 patients (43 hips) (follow-up rate 78%), were available at a minimum of 28 years after surgery. Results: In the pre-OA group, the mean Merle d'Aubigné score improved significantly from 14.5 points (SD 0.7) preoperatively to 17.4 points at final follow-up (SD 1.2; p = 0.004) and in the early-stage group, the mean score did not improve significantly from 14.0 (SD 0.3) to 14.6 (SD 2.4; p = 0.280). Radiologically, the centre-edge angle, acetabular roof angle, and head lateralization index were significantly improved postoperatively in both groups. Radiological progression of OA was observed in two patients (two hips) in the pre-OA group and 17 patients (18 hips) in the early-stage group. Kaplan-Meier survival analysis, with radiological progression of OA as the primary outcome, projected a 30-year survival rate of 81.8% (95% confidence interval (CI) 0.59 to 1.00) for the pre-OA group and 42.2% (95% CI 0.244 to 0.600) for the early-stage group. In all cases, the overall survival rate stood at 51.5% (95% CI 0.365 to 0.674) over a 30-year period, and when the endpoint was conversion to total hip arthroplasty, the survival rate was 74.0% (95% CI 0.608 to 0.873). Conclusion: For younger patients with pre-OA, joint preservation of over 30 years can be expected after RAO.

Midterm results of femoral impaction bone grafting with an allograft combined with hydroxyapatite in revision total hip arthroplasty.

The purpose of this study was to evaluate the outcome of femoral impaction bone grafting with an allograft combined with hydroxyapatite (HA). Fifty-four consecutive femoral reconstructions that were performed with the use of frozen morselized allografts and HA were followed up retrospectively. The average follow-up period was 92 months. A femoral head and HA were mixed and used as allograft. The average Merle d'Aubigné clinical score improved from 8.9 preoperatively to 13.1 points postoperatively. Stem subsidence was seen in 26 hips; however, it was not progressive after 1 year postoperatively. Cortical repair was detected at an average of 7 months postoperatively. Impaction bone grafting with an allograft combined with HA provided favorable results, with bone remodeling and less subsidence.

Mid-term results of acetabular reconstruction using a Kerboull-type acetabular reinforcement device.

PURPOSE: The purpose of this study was to investigate the mid-term results of 32 acetabular reconstructions performed using a Kerboull-type acetabular reinforcement device and bone graft between June 1997 and January 2009. METHODS: The mean age of the patients at the time of surgery was 71.4 years (range 55-85). Patients were followed-up for a mean of 7.5 years (range 2.1-13.7). The acetabular bone defects according to the American Academy of Orthopaedic Surgeons system was type III for 29 hips and type IV for three hips. Bulk allografts were performed in 30 hips and morselised autografts (iliac bone) were performed in two hips. Clinical evaluations were made according to the criteria of Postel/Merle d'Aubigné. RESULTS: The mean pre-operative Postel/Merle d'Aubigné hip score was 7.0 ± 2.9, and the final follow-up hip score was 12.6 ± 2.8. Six hips showed radiographic loosening, and two hips required further revision. A Kaplan-Meier analysis showed that the five-year and ten-year survival rates were 96.9% and 92.3%, respectively, using further revision of the acetabular device as an end point. CONCLUSION: Acetabular reconstruction using a Kerboull-type acetabular reinforcement device and bone graft gives satisfactory mid-term results.

Clinical and radiographical results of 179 thrust plate hip prostheses: 5-14 years follow-up study.

INTRODUCTION: The thrust plate hip prosthesis (TPP) is a bone-reserving prosthesis for cementless fixation at the metaphysis of the proximal femur. We retrospectively evaluated the results of 162 patients (179 hips) who underwent hip arthroplasty using TPP. PATIENTS AND METHODS: Eighty-three patients (87 hips) suffered from osteoarthritis of the hip joint (OA group), 79 patients (92 hips) from osteonecrosis of the femoral head (ON group). The mean age at surgery was 55 years in the OA group and 47.4 years in the ON group. The mean follow-up period was 97 months in the OA group and 104 months in the ON group. For these patients, we evaluated the results clinically and radiographically. RESULTS: The mean Merle d'Aubigne's score improved from 8.2 to 16.9 in the OA group and from 9.1 to 16.6 in the ON group at the final follow-up. Early mechanical loosening of TPP was observed in two hips of OA and one hip of ON. In one patient of ON, bilateral TPPs had to be removed 5 years postoperatively because of infection. Two female patients with ON suffered from a spontaneous femoral fracture below the tip of the lateral plate. Kaplan-Meier survivorship using TPP removed for any reason as the end point was 97.7% in the OA group and 90.3% in the ON group after 13 years. CONCLUSION: The middle-term results of the TPP were satisfactory if the indication for the TPP and the operative procedure were appropriate. The TPP is a useful and safe prosthesis for relatively young patients with not only osteoarthritis of the hip but also osteonecrosis of the femoral head.

Arthroscopic Treatment for Femoral Nerve Palsy Associated with Ganglion Cyst of the Hip: A Case Report.

INTRODUCTION: There are several case reports of nerve palsy caused by ganglions arising from the hip joint. We herein report the arthroscopic treatment of a patient who presented with femoral numbness due to the compression of the femoral nerve by a ganglion of the hip joint. CASE REPORT: A 61-year-old man presented with a 3-month history of increasing pain in his left groin, and numbness and radiating pain in the anterior and medial thigh caused by a ganglion cyst. Magnetic resonance imaging showed a cyst situated at medial the iliopsoas muscle and tendon. The dimensions of the cyst were 56 mm in the coronal view, 22×24mm in the axial view. The mass, which was compressing the neurovascular bundle, was connected to the hip joint. A ganglion stalk incision was performed using hip arthroscopy, and the pain and numbness disappeared immediately after surgery. At 6months after surgery, the ganglion cyst had almost disappeared. CONCLUSION: It is important to be aware that a ganglion cyst arising from the hip joint may sometimes cause neurological symptoms. The advantage of the arthroscopic procedure that was used in the present case was that the incision site was far from the neurovascular bundle. It was, therefore, safer to perform an arthroscopic stalk incision than it was to perform open surgery.

Healing potential of the cartilage correlates with location on the femoral head: a basic research using a rabbit model.

PURPOSE: The purpose of this study is to investigate whether healing potential of the femoral cartilage differs according to the site of injury in a rabbit, and whether poor potential of the cartilage repair correlates with the injured site which is not in contact with acetabulum. Furthermore, the efficacy of intraarticular injection of hyaluronic acid into the hip for the cartilage with lower healing potential was evaluated. METHODS: Male Japanese white rabbits were used in this study. Via the posterolateral approach, the articular capsule was incised and a 4 × 4 mm chondral defect was made at the load-bearing area (group A) or at head-neck junction (group B), and intraarticular injection of hyaluronic acid was performed to the group B model (group C). RESULTS: In group A, histological evaluation at 8 weeks revealed that the chondral defect was filled with cartilaginous tissue. However, in group B, the chondral defect was not filled with any tissue and subchondral bone was exposed. In group C, the defect was filled with synovial-like tissue, and smooth surface was reacquired macroscopically. According to the ICRS score, significant differences were detected between group A and group B, group A and group C, and group B and group C. There were no differences in the radiographic findings among the 3 groups. CONCLUSIONS: The cartilage at head-neck junction of the femoral head had poorer healing potential than that at load-bearing area. Administration of HA could be promising for preventing progression of cartilage degeneration even at head-neck junction.