Tomonori Baba

Estrogen, Insulin, and Dietary Signals Cooperatively Regulate Longevity Signals to Enhance Resistance to Oxidative Stress in Mice

To investigate the biological significance of a longevity mutation found in daf-2 of Caenorhabditis elegans, we generated a homologous murine model by replacing Pro-1195 of insulin receptors with Leu using a targeted knock-in strategy. Homozygous mice died in the neonatal stage from diabetic ketoacidosis, whereas heterozygous mice showed the suppressed kinase activity of the insulin receptor but grew normally without spontaneously developing diabetes during adulthood. We examined heterozygous insulin receptor mutant mice for longevity phenotypes. Under 80% oxygen, mutant female mice survived 33.3% longer than wild-type female mice, whereas mutant male mice survived 18.2% longer than wild-type male mice. These results suggested that mutant mice acquired more resistance to oxidative stress, but the benefit of the longevity mutation was more pronounced in females than males. Manganese superoxide dismutase activity in mutant mice was significantly upregulated, suggesting that the suppressed insulin signaling leads to an enhanced antioxidant defense. To analyze the molecular basis of the gender difference, we administered estrogen to mutant mice. It was found that the survival of mice under 80% oxygen was extended when they were administered estradiol. In contrast, mutant and wild-type female mice showed shortened survivals when their ovaries were removed. The influence of estrogen is remarkable in mutant mice compared with wild-type mice, suggesting that estrogen modulates insulin signaling in mutant mice. Furthermore, we showed additional extension of survival under oxidative conditions when their diet was restricted. Collectively, we show that three distinct signals; insulin, estrogen, and dietary signals work in independent and cooperative ways to enhance the resistance to oxidative stress in mice.

The fracture sites of atypical femoral fractures are associated with the weight-bearing lower limb alignment

PURPOSE Atypical femoral fractures (AFFs) are stress-related fractures that are speculated to associate with long-term treatment with bisphosphonates for osteoporosis. A history of AFF is a high risk factor for the development of a subsequent AFF in the same location of the contralateral femur, suggesting that a patients individual anatomical factor(s) are related to the fracture site of AFFs. In this study, we investigated the radiographs of fourteen AFFs (four bilateral fractures among ten patients) treated at six hospitals associated with our university between 2005 and 2010. The fracture site and standing femorotibial angle (FTA), which reflects the mechanical axis of the lower limb, were measured on weight-bearing lower limb radiographs. The fracture site and FTA of patients with typical femoral fractures (TFF) were compared to those of patients with AFFs. The correlations were examined using Spearmans rank correlation coefficients. The fracture locations in the femora were almost the same in the patients with bilateral AFFs. There was a positive correlation between the fracture site and the standing FTA in the patients with AFFs (r=0.82, 95% confidence interval; 0.49 to 0.94), indicating that the larger the standing FTA (varus alignment), the more distal the site of the fracture in the femur. The FTA of the patients with atypical diaphyseal femoral fracture were significantly larger compared to that of those with not only atypical subtrochanteric fractures but also TFFs. In conclusion, the fracture sites of AFFs are associated with the standing lower limb alignment, while those of TFFs are not.

Bipolar hemiarthroplasty for femoral neck fracture using the direct anterior approach

AIM To evaluate whether walking ability recovers early after bipolar hemiarthroplasty (BHA) using a direct anterior approach. METHODS Between 2008 and 2010, 81 patients with femoral neck fracture underwent BHA using the direct anterior approach (DAA) or the posterior approach (PA). The mean observation period was 36 mo. The age, sex, body mass index (BMI), time from admission to surgery, length of hospitalization, outcome after discharge, walking ability, duration of surgery, blood loss and complications were compared. RESULTS There was no significant difference in the age, sex, BMI, time from admission to surgery, length of hospitalization, outcome after discharge, duration of surgery and blood loss between the two groups. Two weeks after the operation, assistance was not necessary for walking in the hospital in 65.0% of the patients in the DAA group and in 33.3% in the PA group (P < 0.05). As for complications, fracture of the femoral greater trochanter developed in 1 patient in the DAA group and calcar crack and dislocation in 1 patient each in the PA group. CONCLUSION DAA is an approach more useful for BHA for femoral neck fracture in elderly patients than total hip arthroplasty in terms of the early acquisition of walking ability.

Revision of total hip arthroplasty using the Kerboull and KT plates

We reviewed 42 hips which had undergone revision THA between 1995 and 2005 (the Kerboull plate in 24 hips, and the KT plate in 18 hips). Patients were followed-up for a mean of 7.5 years (range 3–13). In the Kerboull plate group, the five- and ten-year survival rates were 89.9% and 79.4%, respectively. In the KT plate group, the five-year survival rate was 87.5%. The Kerboull and KT plates are placed as close as possible to the original acetabular position and used in combination with a bone graft for bone defects. In Japan, for patients with large bone defects, femoral heads with good quality which have been resected due to osteoarthritis are difficult to prepare as bone grafts. Therefore, use of the KT plate can reduce the bone graft volume to a certain extent by high placement, which was effective in our cases.

Evaluation of the clinical results of posterior cruciate ligament reconstruction -a comparison between the use of the bone tendon bone and semitendinosus and gracilis tendons-

Reconstruction of the posterior cruciate ligament (PCL) is still in the middle of development. The postoperative results of PCL reconstruction using bone tendon bone (BTB) and semitendinosus and gracilis tendons (STG) were compared and studied retrospectively. The purpose of the present study was to clarify the features of the two surgical methods and explore the problems associated with these procedures and measures to improve them.

Comparison of therapeutic outcomes of periprosthetic femoral fracture between treatments employing locking and conventional plates.

IntroductionLocking plate is considered biomechanically advantageous for porotic bone, compared with conventional plate. However, clinical evaluations of locking and conventional plates for periprosthetic femoral fracture are still controversial. Thus, we investigated the usefulness of a locking plate compared with the conventional plate for treatment for this fracture.Materials and methodsWe reviewed 40 patients (40 fractures) who had undergone internal fixation for Vancouver type B1 or C periprosthetic fracture. Locking and conventional plates were applied for 21 and 19 patients, respectively.ResultsNo significant difference was found between locking and conventional plate groups in Merle d’ Aubigné hip score, walking ability, operation time, and blood loss. Regarding postoperative complications, delayed union was noted in one patient in the locking plate group and subsidence of the stem in one in the conventional plate group. On the final follow-up, bone union was achieved in all patients.ConclusionWe cannot suggest the usefulness of locking plate for periprosthetic femoral fracture. However, functional training was performed in the same rehabilitation schedule in our comparative study. Considering the angle stability of the locking plate, weight may be loaded on the locking plate, earlier than that on the conventional plate, which may be an advantage of the locking plate.

Spontaneous healing of lateral femoral cutaneous nerve injury and improved quality of life after total hip arthroplasty via a direct anterior approach: Survey at average 12.8 and 26.2 months of follow-up

Purpose: How the symptomatology of lateral femoral cutaneous nerve (LFCN) injury changes after total hip arthroplasty (THA) via direct anterior approach (DAA) is not known. Our hypothesis was that the symptoms of LFCN injury after THA via DAA in longer follow-up periods would resolve spontaneously, leading to an improved quality of life (QOL). The aims of this study were to investigate how the symptom LFCN injury changed after DAA–THA, and how those changes affected QOL. Methods: We investigated the incidence of LFCN injury after DAA–THA using self-reported questionnaires at two time points (initial survey: August 2014, present survey: August 2015). QOL was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire, and the Forgotten Joint Score-12 (FJS-12). Types (dysesthesia or hypesthesia) and changes of the symptom were surveyed. Results: About 122 hips at average12.8 months postoperatively (initial survey), and of those, 89 hips at average 26.2 months postoperatively (present survey) were analyzed. The incidence of LFCN injury decreased significantly, from 31.9% to 11.2% (p < 0.001). Spontaneous improvement of symptoms was seen in 96%. The difference of FJS-12 between patients with and without LFCN injury at the initial survey disappeared at the present survey. The dysesthesia group showed significant correlations between rate of improvement in LFCN injury and increase of QOL. Conclusion: Most symptoms of LFCN injury resolved spontaneously with longer follow-up periods. In particular, improvement of dysesthesia as a symptom of LFCN injury was associated with better QOL.

New classification focusing on the relationship between the attachment of the iliofemoral ligament and the course of the fracture line for intertrochanteric fractures

PURPOSE There are various types of intertrochanteric fractures that are unstable pertrochanteric fractures of the hip. The aim of this study was to develop a systematic and comprehensive classification of intertrochanteric fractures. MATERIALS AND METHODS This study enrolled 74 patients with intertrochanteric fractures treated by us between 2012 and 2015. The fractures were classified using 3D-CT images taken immediately after the fractures occurred based on the course of the lateral fracture line (LFL) that extends through the lateral femoral cortex distal to the vastus ridge of the greater trochanter in the intertrochanteric area. Furthermore, the presence or absence of additional typical fractures was also studied. Then, 4 orthopedic specialists examined the 3D-CT images of 20 patients randomly selected from the 74 patients to evaluate both the inter-rater and intra-rater agreement levels. RESULTS Intertrochanteric fractures were classified into three types according to the LFL patterns. Type I (41.9%), the Lateral Wall Pattern, has a LFL that extends towards the lateral fiber bundle attachment area of the iliofemoral ligament. Type II (24.3%), the Transverse Pattern, has a LFL that extends towards the medial bundle attachment area. Type III (33.8%), the Reverse Oblique Pattern, has a LFL that extends between the lateral and medial fiber bundle area of the iliofemoral ligament. Each type showed characteristic displacement and was associated with various combinations of typical fractures (fracture across the intertrochanteric line, posteromedial fragment, including the lesser trochanter, posterolateral fragment posterior to the femoral greater trochanter, and banana-shaped big fragment, including both the greater trochanter and the lesser trochanter). The mean κ values for the interobserver and intraobserver agreement levels were 0.77 (0.70-0.85) and 0.76 (0.70-0.85), respectively, which were considered substantial agreement levels. CONCLUSION We believe our new classification is a useful communication tool for medical professionals in the diagnosis of fractures.

Kerboull-type plate in a direct anterior approach for severe bone defects at primary total hip arthroplasty: technical note

Introduction: For cases with extensive acetabular bone defects, we perform surgery combining the Kerboull-type (KT) plate and bone graft through direct anterior approach (DAA) in primary total hip arthroplasty (THA) requiring acetabular reconstruction as minimally invasive surgery. This paper provides the details of the surgical procedure. Methods: The basic structure of the Kerboull-type plate is a cruciform plate. Since the hook of the Kerboull-type plate has to be applied to the tear drop, a space for it was exposed. The tear drop is located in the anterior lower region in surgery through DAA in supine position. It was also confirmed by fluoroscopy as needed. The bone grafting was performed using an auto- or allogeneic femoral head for bone defects in the weight-bearing region of the hip joint. Results: Of 563 patients who underwent primary THA between 2012 and 2014, THA using the KT plate through DAA was performed in 21 patients (3.7%). The mean duration of postoperative follow-up was 31.8 months. The mean operative time was 188.4 min, and the mean blood loss was 770 g. The patients became able to walk independently after 2.4 days on average (1–4 days). On clinical evaluation, the modified Harris Hip Score was 45.6 ± 12.4 before surgery, and it was significantly improved to 85.3 ± 8.97 on the final follow-up. Discussion: DAA is a true intermuscular approach capable of conserving soft tissue. Since it is applied in a supine position, fluoroscopy can be readily used, and it was very useful to accurately place the plate.

Rapid hip osteoarthritis development in a patient with anterior acetabular cyst with sagittal alignment change.

Rapidly destructive coxarthrosis (RDC) is rare and develops unusual clinical course. Recent studies suggest multiple possible mechanisms of the development of RDC. However the exact mechanism of RDC is still not clear. The difficulty of the study on RDC is attributed to its rareness and the fact that the data before the onset of RDC is normally unavailable. In this report, we presented the patient having the radiographic data before the onset who had rapid osteoarthritis (OA) development after contralateral THA, which meets the current criteria of RDC. We thought that the increased posterior tilt of the pelvis after THA reinforced the stress concentration at pre-existed anterior acetabular cyst, thereby the destruction of the cyst was occurred. As a result the rapid OA was developed. We think that there is the case of rapid osteoarthritis developing due to alternating load concentration by posterior pelvic tilt on preexisting anterior acetabular cyst such as our patient among the cases diagnosed as RDC without any identifiable etiology. The recognition of sagittal alignment changes and anterior acetabular cyst may play important role in prediction and prevention of the rapid hip osteoarthritis development similar to RDC.