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Featured researches published by Osamu Obayashi.


Bone | 2014

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

Yoshitomo Saita; Muneaki Ishijima; Atsuhiko Mogami; Mitsuaki Kubota; Tomonori Baba; Takefumi Kaketa; Masashi Nagao; Yuko Sakamoto; Kensuke Sakai; Rui Kato; Nana Nagura; Kei Miyagawa; Tomoki Wada; L. Liu; Osamu Obayashi; Katsuo Shitoto; Masahiko Nozawa; Hajime Kajihara; Hogaku Gen; Kazuo Kaneko

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.


European Journal of Orthopaedic Surgery and Traumatology | 2008

Fracture of the calcium phosphate bone cement which used to enchondroma of the hand: a case report

Kiyohito Naito; Osamu Obayashi; Atsuhiko Mogami; Akira Itoi; Kazuo Kaneko

Enchondroma of a hand is a common benign tumor. Enchondroma commonly presents as a pathological fracture associated with pain, deformity, and swelling. Dysfunction of the fingers occurs as a result of the fracture. Curettage is the mainstay of surgical treatment for enchondroma.


Injury-international Journal of The Care of The Injured | 2016

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

Kentaro Futamura; Tomonori Baba; Yasuhiro Homma; Atsuhiko Mogami; Akio Kanda; Osamu Obayashi; Kazuo Sato; Yasuhisa Ueda; Yoshiaki Kurata; Hideki Tsuji; Kazuo Kaneko

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.


International Orthopaedics | 2018

“Within ring”-based sacroiliac rod fixation may overcome the weakness of spinopelvic fixation for unstable pelvic ring injuries: technical notes and clinical outcomes

Kentaro Futamura; Tomonori Baba; Atsuhiko Mogami; Akio Kanda; Osamu Obayashi; Hideaki Iwase; Kazuo Kaneko

PurposeSpinopelvic fixation and triangular osteosynthesis give firm internal fixation for unstable pelvic ring injuries (UPRI), but with sacrifice of mobility of the lumbar spine. Here, we describe the procedure and outcomes of a new approach, which we refer to as “within ring”-based sacroiliac rod fixation (SIRF).MethodsThe patient was placed in a prone position and longitudinal skin incisions were made at the medial margins of the bilateral posterior superior iliac spines (PSIS). After reduction of fracture, a pedicle screw was inserted into the first sacral vertebra on the injured side and iliac screws inserted through the bilateral PSIS were bridged using rods.ResultsSIRF was performed in 15 patients. The AO/OTA classification was 61-B2.3 in 1, C1.3 in 4, C2.3 in 7, C3.3 in 1, and H-type spinopelvic dissociation in two cases. The mean operative time was 179 (110–298) minutes, mean blood loss was 533 (100–2700) cc. One patient died during hospitalization and three patients stopped outpatient treatment. The other 11 patients achieved bone union without major loss of reduction in a mean post-operative follow-up period of 23.8 (4–50) months. The mean Majeed score at final follow-up was 86.7 (73–96) out of 96, excluding scoring sexual intercourse.Conclusions“Within ring”-based SIRF not including the lumbar spine in the fixation range is a simple, safe, and low-invasive internal fixation method for UPRI.


Injury-international Journal of The Care of The Injured | 2017

Malreduction of syndesmosis injury associated with malleolar ankle fracture can be avoided using Weber's three indexes in the mortise view

Kentaro Futamura; Tomonori Baba; Atsuhiko Mogami; Itaru Morohashi; Akio Kanda; Osamu Obayashi; Kazuo Sato; Yasuhisa Ueda; Yoshiaki Kurata; Hideki Tsuji; Kazuo Kaneko

PURPOSE Malalignment of syndesmosis is generally associated with a poor outcome, yet occurs at a high rate in malleolar ankle fractures. In this study, we examine whether malreduction of syndesmosis injury associated with malleolar ankle fracture can be avoided using Webers three indexes in the mortise view. MATERIALS AND METHODS Of 156 patients with malleolar ankle fracture who underwent surgery from December 2012 to March 2016 at two medical facilities, 24 patients who received syndesmotic screw fixation were included in the study. Fractures were Danis-Weber types B and C in 8 (8/134, 6.0%) and 16 (16/22, 72.7%) patients, respectively. Using axial computed tomography (CT), we calculated the difference between injured and non-injured sides for each of three parameters: tibiofibular clear space (TFCS), anterior tibiofibular interval (ATF), and fibular rotation (θfib). Malreduction was diagnosed if one or more of the three parameters had an abnormal value. Webers three indexes in the mortise view on the injured side were used to determine whether reduction of syndesmosis was performed successfully. Consistency between the evaluation of reduction of syndesmosis in axial CT images and reevaluation of mortise views was examined by calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS The rate of malreduction of syndesmosis in axial CT images was 29.2% (7/24). Re-evaluation in the mortise view confirmed malreduction of syndesmosis in six of the seven subjects, all of whom also had malreduction based on axial CT images. The one subject in whom malreduction could not be detected in a mortise view showed an abnormal value only for ATF. Use of the mortise view for perioperative diagnosis had a sensitivity of 0.857, specificity of 1.000, PPV of 1.000, and NPV of 0.944. CONCLUSION The results of our study show that malreduction of syndesmosis can be avoided by careful interpretation of intraoperative perspective mortise views based on Webers three indexes. To increase the diagnostic accuracy further, it is important to detect anteroposterior deviation of the fibula in intraoperative lateral views.


Annals of medicine and surgery | 2016

Iliopsoas impingement after revision total hip arthroplasty treated with iliopsoas muscle transection

Itaru Morohashi; Yasuhiro Homma; Akio Kanda; Yasuhiro Yamamoto; Hiroyuki Obata; Atsuhiko Mogami; Osamu Obayashi; Kazuo Kaneko

Introduction Iliopsoas tendinitis after revision total hip arthroplasty (THA) is rare and its etiology and optimal treatment are still unclear. We report a case of iliopsoas impingement after revision THA with a Kerboull acetabular reinforcement device requiring two-level iliopsoas muscle transection. Presentation of case A 70-year-old woman presented to our hospital complaining of debilitating right groin pain after revision THA with a Kerboull reinforcement device. She had undergone multiple hip operations after experiencing a pelvic fracture in a motor vehicle accident. A lidocaine nerve block at the level of the Kerboull device resulted in temporary but marked reduction in pain and a diagnosis of psoas impingent. We performed surgery via an anterior approach to release the iliopsoas muscle from the lesser trochanter. After iliopsoas tenotomy was performed, the muscle was still under high tension because of dense adhesions. Repeat transection of the iliopsoas muscle at the level of the anterior branch of the Kerboull device resulted in loosening of the iliopsoas muscle and resolution of impingement. Postoperatively, the patients groin pain completely disappeared, and she can now walk with a single cane and is satisfied with her result. Discussion Adhesions around the iliopsoas muscle likely contributed to the patients groin pain. Open surgery to perform complete release of iliopsoas muscle impingement should be considered in patients with pain after revision THA. Conclusion We reported a patient with Iliopsoas tendinitis after revision THA requiring two-level iliopsoas muscle transection.


Journal of Medical Case Reports | 2015

A 42-year-old patient presenting with femoral head migration after hemiarthroplasty performed 22 years earlier: a case report

Akio Kanda; Kazuo Kaneko; Osamu Obayashi; Atsuhiko Mogami

IntroductionTreatment of femoral neck fractures in young adults may require total hip arthroplasty or hip hemiarthroplasty using a bipolar cup. The latter can, however, result in migration of the femoral head and poor long-term results.Case presentationWe report a case of femoral head migration after hemiarthroplasty performed for femoral neck fracture that had occurred 22 years earlier, when the patient (a Japanese man) was 20 years old. He experienced peri-prosthetic fracture of the femur, subsequent migration of the prosthesis, and a massive bone defect of the pelvic side acetabular roof. After bone union of the femoral shaft fracture, the patient was referred to our hospital for reconstruction of the acetabular roof. Intra-operatively, we placed two alloimplants of bone from around the transplanted femoral head into the weight-bearing region of the acetabular roof using an impaction bone graft method. We then implanted an acetabular roof reinforcement plate and a cemented polyethylene cup in the position of the original acetabular cup. Eighteen months post-operatively, X-rays showed union of the transplanted bone.ConclusionsTreatment of femoral neck fractures in young adults is usually accomplished by osteosynthesis, but it may be complicated by femoral head avascular necrosis or by infection or osteomyelitis. In such cases, once an infection has subsided, either hip hemiarthroplasty using a bipolar cup or total hip arthroplasty may be required. However, if the acetabular side articular cartilage is damaged, a bipolar cup should not be used. Total hip arthroplasty should be performed to prevent migration of the implant.


Hand Surgery | 2013

HAMATE HOOK NON-UNION TREATED WITH A BREAK-AWAY SCREW: A CASE REPORT

Kiyohito Naito; Kei Yoshikawa; Kazuo Kaneko; Osamu Obayashi

Hamate hook non-union is a relatively rare, but on the increase. We encountered a 25-year-old male baseball instructor with hamate hook non-union, and treated it with debridement of the fractured region and osteosynthesis using a break-away screw. Splint fixation was applied for three weeks after surgery, and active/passive range of motion exercises were actively performed thereafter. Bone union was noted three months after surgery. Transient ulnar paralysis resolved, and the patient could return to the same sports activity as that before injury six months after surgery. Since break-away screws are capable of loading a strong pressure on the fractured region and these screws can be inserted by preparing only a surgical field for guide wire insertion, requiring no soft tissue dissection to prepare a region for applying fixation materials, break-away screws are useful for the fixation of small bone fragments and osteosynthesis in a deep surgical field.


Case reports in orthopedics | 2013

The Massive Bleeding after the Operation of Hip Joint Surgery with the Acquired Haemorrhagic Coagulation Factor XIII(13) Deficiency: Two Case Reports.

Akio Kanda; Kazuo Kaneko; Osamu Obayashi; Atsuhiko Mogami

Two women, aged 81 and 61, became haemorrhagic after surgery. Their previous surgeries were uneventful with no unexpected bleeding observed. Blood tests prior to the current surgeries indicated normal values including those related to coagulation. There were no problems with the current surgeries prior to leaving the operating room. At 3 hours after the surgery, the 81-year-old patient had an outflow of the drain at 1290 grams and her blood pressure decreased. She had disseminated intravascular coagulation (DIC). The 61-year-old woman had repeated haemorrhages after her current surgery for a long time. Their abnormal haemorrhages were caused by a deficiency of coagulation factor XIII(13). The mechanism of haemorrhagic coagulation factor XIII(13) deficiency is not understood, and it is a rare disorder. The only diagnostic method to detect this disorder is to measure factor XIII(13) activity in the blood. In this paper, we used Arabic and Roman numerals at the same time to avoid confusion of coagulation factor XIII(13) with coagulation factor VIII(8) that causes hemophilia A.


Cases Journal | 2009

Acute posterior neck pain in adult: a case series

Yasuhiro Homma; Akira Itoi; Tomoya Muta; Yoshio Shimamura; Kiyohito Naito; Atsuhiko Mogami; Osamu Obayashi; Colin G. Murphy; Kazuo Kaneko

Calcification around the cervical spine is thought to be relatively rare case, among these conditions the calcification at the longus colli muscle is called retropharyngeal tendinitis and only several cases were reported in the literature. In this disease, the three characteristic clinical features are acute severe posterior neck pain without any trigger, severely restricted range of motion, and odynophagia. The radiographic findings include swelling of the retropharyngeal space and amorphous calcification anterior to C1-C2 in lateral view of the cervical spine. Diagnosis is established by sound history taking coupled with computed tomography (CT) scan of the affected area, treatment is the administration of oral non-steroidal anti-inflammatory drugs (NSAID), for a few weeks and/or oral steroid. We present a new 3 cases (27, 35, and 24 years old, male) and review of literature.

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