Eiichi Genda

The natural course of osteoarthritis of the hip due to subluxation or acetabular dysplasia.

SummaryIn 59 patients, 86 hips with subluxation or hip dysplasia were examined to determine the natural course of the condition and select suitable treatment. Thirty-three percent of the joints (13/39 hips) developed early osteoarthritis from pre-osteoarthritis within an average term of 9.2 years, while the remaining, sixty-six percent (31/47 hips) developed advanced-stage osteoarthritis from early osteoarthritis within an average term of 7.8 years. Patients were classified into advanced and non-advanced groups according to radiographic analysis of the advance of the disease and statistical analysis was performed. In pre-osteoarthritis, centre-edge angle, slope of the acetabular roof, acetabular head index, acetabular depth ratio and Japanese Orthopaedic Association (JOA) hip score were significant predictors, while in early osteoarthritis, a broken Shentons line, cranial joint space and JOA score were significant. On the basis of multiple parameters, formulas for predicting development in patients with pre-osteoarthritis, those with early osteoarthritis, and all patients together were established, with an accuracy of 87%, 71%, and 68%, respectively.

Indications and results of vascularized pedicle iliac bone graft in avascular necrosis of the femoral head

Several reports describe methods of treatment for avascular necrosis of the femoral head (ANFH) involving 0 to 2 mm of collapse. Some cases of ANFH have good prognoses, requiring only non-weight-bearing treatment. Other cases rapidly progress to collapse and complete destruction with enlargement of the necrotic area. The progression of the necrotic area is related to the activity of the original disease, steroid treatment, and the size and location of the necrotic area in the early stages of the disorder. In this report, a vascularized pedicle bone graft was used to treat ANFH, particularly those cases identified as Stage II on the system established by the Japanese Investigation Committee. Surgery involved curettage of necrotic bone, implantation of spongy bone, and application of a vascularized pedicle bone graft. Grafts were taken from the ilium and included the superficial circumflex iliac artery (SCIA). A bony canal was made in the anterior femoral neck, from which the necrotic bone was curetted and to which the bone graft was applied. The deep circumflex iliac artery (DCIA) was also used in combination with the SCIA. The postoperative weight-bearing period was six months. Follow-up periods lasted one to six years. Seventeen of 23 Stage II joints (19 cases) achieved satisfactory results at a mean of three years after surgery. Three Stage II joints and three Stage III joints continue to have significant problems. One of these six has been converted to a dual-bearing type endoprosthesis. The unsuccessful results generally occurred in patients who were treated with steroids.

Inhibitory effect of bFGF on endochondral heterotopic ossification

Basic fibroblast growth factor (bFGF) is reported to stimulate repair of fracture and bony defects in in vivo animal studies. However, most studies performed in vitro demonstrate inhibitory effect of bFGF on cartilage and bone differentiation. To understand the discrepancy observed in in vivo and in vitro studies, we evaluated the effect of bFGF on chondro-osteogenesis initiated by bone matrix powder (MP). MP was implanted in the murine hamstring muscles with or without administration of bFGF. Injection of 1 microg of bFGF markedly reduced the size of heterotopic bone induced by MP, as detected by X-ray. Injection of 10 microg of bFGF completely inhibited ossification and only fibrous tissues were observed at the site of MP implantation. The expressions of alkaline phosphatase and osteocalcin mRNAs, markers for bone differentiation, were completely suppressed by 10 microg of bFGF. These results demonstrate the inhibitory effect of bFGF on endochondral ossification in vivo, implicating a precaution for its use in musculo-skeletal disorders.

Effect of hyperbaric oxygenation on femoral head osteonecrosis in spontaneously hypertensive rats

We investigated the effects of hyperbaric oxygenation (HBO) on ischemic osteonecrosis and on ossification disturbance of the femoral heads in growing, spontaneously hypertensive rats (SHR). 10 male SHRs aged 5 weeks (Group A) and another 10 male SHRs aged 8 weeks (Group B) were treated with HBO at 2.8 atmosphere absolute (ATA) for 6 weeks in a total of 30 hours. The control animals, 10 male SHRs (Group C) and 10 male wistar Kyoto rats (WKY, Group D), were kept under normal laboratory conditions. All the rats were killed at the age of 17 weeks for microscopic examination. In Group A, there was no evidence of osteonecrosis, and only 2 femoral heads with ossification disturbance were observed. In Group B, there were 2 femoral heads with osteonecrosis and 1 with ossification disturbance. In contrast, there were 6 femoral heads with osteonecrosis and 4 with ossification disturbance in Group C. It was concluded that HBO prevented osteonecrosis and ossification disturbance of the femoral heads in SHR.

Robot-aided rehabilitation task design for inner shoulder muscles

In this paper, we propose a simultaneous design method of motion and external force trajectories for shoulder inner muscles in the robot-aided rehabilitation system, based on a biomechanical analysis of patients body. The rehabilitation efficiency evaluation function was maximized by Genetic Algorithm (GA), where the structure of spline curves parameters are pre-defined, and the structural parameters are explored to design smooth rehabilitation motion and external force trajectories.

Comparison of Robot-aided Shoulder Exercise to Weight-based Exercise

In this study, we propose a new design method of motion and external force trajectories for the rehabilitation of inner shoulder muscles based on the biomechanical analysis of the upper limbs. The method is assumed to use a robot manipulator; therefore, it enjoys the advantage of providing 3-dimensional trajectories and applied forces to the patient. Both the trajectories of rehabilitation motion and the applied force by the robot are designed in the same planning stage, in order to maximize the rehabilitation efficiency evaluation function based on the biomechanical analysis of the patient for each joints torque, each muscles force, and each joints reaction force. In order to focus the spotlight on the advantages of the proposed robot-aided method, an example is given for comparison with a weight-based method which is supposed to use a weight for providing force to the patient. The comparison demonstrates the advantage of the proposed method in a quantitative manner from several rehabilitation points ...

State estimation of walking phase and functional electrical stimulation by wearable device

Functional electrical stimulation (FES) is useful to improve the gait of patients with peroneal nerve palsy or spastic hemiparesis after stroke. So as to apply FES to such patients, we have to have estimators for detecting the timing of phase switching in walking motion. We designed a wearable device for state estimating of walking and functional electrical stimulation. We consider the implementation of artificial neural network (ANN) into the device, and propose a method for supervised learning of the ANN. Two experiments have been conducted to show the effectiveness of the wearable device. The accuracy of estimating the timing for FES is good enough for the practical application.

Robot-aided motion planning for knee joint rehabilitation with two robot-manipulators

In this paper, we propose a simultaneous design method of motion and external force trajectories for knee joint rehabilitation based on the biomechanical analysis of the lower limb. In this method we assume to use two robots manipulators which provide forces and moments at shank and thigh. We developed a 7 degree of freedom musculoskeletal model of lower limb with 19 muscles. The valuation function of rehabilitation efficiency e has been maximized by Genetic Algorithm (GA) that refers to the musculoskeletal model and tunes motion trajectory of the robots and forces acting on the shank and thigh.