Toshiaki Aizawa

Electrical Stimulation Using Implantable Radiofrequency Microstimulators to Relieve Pain Associated With Shoulder Subluxation in Chronic Hemiplegic Stroke

Objective.  To evaluate the ability to relieve shoulder pain by implanting ceramic‐case versions of radiofrequency microstimulators (RFM) in paralyzed shoulder muscles.

The Serum 25(OH)D Level in Patients with Atypical Femoral Fracture

Objective: Excessive curvature of the femur has been considered to be one of the factors associated with atypical femoral fracture (AFF). Although we clarified that femoral curvature was markedly influenced by a low vitamin D level, very few studies have been conducted on the direct relationship between AFF and a serum low level of vitamin D. Therefore, we compared the serum vitamin D level between AFF and osteoporosis patients. Methods: A total of 48 consecutive AFFs in 36 Japanese patients were retrospectively reviewed using the medical records, and 12 consecutive AFFs in 9 patients (AFF group) whose 25-hydroxyvitamin D (25(OH)D) levels were examined were included in this study. As a non-AFF control group, 45 consecutive age-matched female patients with osteoporosis (Osteoporosis group) were enrolled. We compared some laboratory examination items, the bone mineral density, and curvature of the femur. Results: When univariate logistic regression analysis was performed to compare the 2 groups, Ca levels and lateral and anterior curvatures in the AFF group were significantly greater than in the Osteoporosis group (P < 0.05, P < 0.01, and P < 0.01, respectively), and the 25(OH)D level in the AFF group was significantly lower than in the Osteoporosis group (P < 0.01). We used discriminant analysis of these extracted items to exclude the mutual influence of factors and identify factors closely associated with AFF, and 25(OH)D, Ca and anterior curvature were identified as significant items to differentiate these diseases (P < 0.05, P < 0.01, and P < 0.01, respectively). Conclusion: AFF patients showed low vitamin D levels and marked femoral curvatures.

Gait Analysis of Conventional Total Knee Arthroplasty and Bicruciate Stabilized Total Knee Arthroplasty Using a Triaxial Accelerometer

One component of conventional total knee arthroplasty is removal of the anterior cruciate ligament, and the knee after total knee arthroplasty has been said to be a knee with anterior cruciate ligament dysfunction. Bicruciate stabilized total knee arthroplasty is believed to reproduce anterior cruciate ligament function in the implant and provide anterior stability. Conventional total knee arthroplasty was performed on the right knee and bicruciate stabilized total knee arthroplasty was performed on the left knee in the same patient, and a triaxial accelerometer was fitted to both knees after surgery. Gait analysis was then performed and is reported here. The subject was a 78-year-old woman who underwent conventional total knee arthroplasty on her right knee and bicruciate stabilized total knee arthroplasty on her left knee. On the femoral side with bicruciate stabilized total knee arthroplasty, compared to conventional total knee arthroplasty, there was little acceleration in the x-axis direction (anteroposterior direction) in the early swing phase. Bicruciate stabilized total knee arthroplasty may be able to replace anterior cruciate ligament function due to the structure of the implant and proper anteroposterior positioning.

Model simulation of FES for the treatment of shoulder subluxation

Recently, functional electrical stimulation (FES) has been applied for the treatment of the shoulder subluxation. The purpose of this study is to design a musculo-skeletal dynamic model for hemiplegic shoulder subluxation with which can perform FES effectively as well as the simulation of shoulder motion by FES. We installed the muscle models into the skeletal model. In this model, scapula and clavicle are fixed, and only gleno-humeral joint can move. We set up muscle activation, and stimulate deltoideus and supuraspinatus. As a result of simulation, we can confirm the reduction of shoulder subluxation.