Toru Nishiwaki

Reduced Expression of Thrombospondins and Craniofacial Dysmorphism in Mice Overexpressing Fra1

Fra1 transgenic (Tg) mice develop osteosclerosis and exhibit altered expression of bone matrix proteins. We found that expression of Thbs1 and Thbs2 was reduced in Fra1 Tg osteoblasts. Fra1 Tg and non‐osteosclerotic Thbs1−/−Thbs2−/− mice share an edge‐to‐edge bite. Therefore, reduced expression of thrombospondins may contribute to craniofacial dysmorphism independently of osteosclerosis.

Curved periacetabular osteotomy via a novel intermuscular approach between the sartorius and iliac muscles

Introduction: Herein, we describe and evaluate a curved periacetabular osteotomy (CPO) via an intermuscular approach (IM-CPO) between the sartorius and iliac muscles. Methods: Between January 2009 and January 2016, IM-CPO was performed in 17 joints (16 patients), and a traditional CPO was performed in 17 joints. The length of incision at wound closure, operative time, intraoperative blood loss, serum creatinine kinase (CK) level the day after surgery, correctional angle, walking ability assessed using the gait items of the Harris Hip Score (at 3 and 6 months after surgery), and perioperative complications were evaluated. Group differences were assessed using t-tests. Results: The IM-CPO and CPO groups did not differ in the mean operative time (130 minutes and 124 minutes, respectively), mean serum CK the day after surgery (349 IU/L and 425 IU/L, respectively), or mean correctional angle (24.9° and 24.6°, respectively). The mean incision length was significantly shorter in the IM-CPO group (8.3 cm) compared to that in the CPO group (9.5 cm). The mean walking ability was significantly higher in the IM-CPO group (24.2 points) compared to that in the CPO group (20.9 points) at 3 months after surgery, but not at 6 months after surgery (26.4 points and 24.9 points, respectively). No serious complications were observed in either group. Conclusion: In addition to demonstrating a similarly satisfactory correctional angle, IM-CPO is anticipated to enable early weight-bearing and recovery of walking ability. Thus, IM-CPO is considered a superior surgical technique.

Tumor necrosis factor receptor-associated factor 6 is required to inhibit foreign body giant cell formation and activate osteoclasts under inflammatory and infectious conditions

Osteoclasts and foreign body giant cells (FBGCs) are derived from common progenitors and share properties such as multi-nucleation capacity induced by cell–cell fusion; however, mechanisms underlying lineage determination between these cells remain unclear. Here we show that, under inflammatory conditions, osteoclasts are stimulated in a manner similar to M1 macrophages, while formation of FBGCs, which exhibit M2-like phenotypes, is inhibited in a manner similar to that seen in M1/M2 macrophage polarization. FBGC/osteoclast polarization was inhibited by conditional knockout of tumor necrosis factor receptor associated factor 6 (Traf6) in adults in vivo and in vitro. Traf6-null mice were previously reported to die soon after birth, but we found that Traf6 deletion in adults did not cause lethality but rather inhibited osteoclast activation and prevented FBGC inhibition under inflammatory conditions. Accordingly, basal osteoclastogenesis was significantly inhibited by Traf6 deletion in vivo and in vitro and accompanied by increased bone mass. Lipopolysaccharide-induced osteoclast formation and osteolysis were significantly inhibited in Traf6 conditional knockout mice. Our results suggest that Traf6 plays a crucial role in regulating M1 osteoclast and M2 FBGC polarization and is a potential therapeutic target in blocking FBGC inhibition, antagonizing osteolysis in inflammatory conditions, and increasing bone mass without adverse effects in adults.

Pseudoarthrosis of the ilium after periacetabular osteotomy that was treated by cemented total hip arthroplasty: a case report

BackgroundPreserving the hip joint to delay arthroplasty for patients with acetabular dysplasia-associated early-stage osteoarthritis has become more common, and several surgical procedures have demonstrated pain relief and improved hip joint function. Periacetabular osteotomy, one of the joint-preserving surgical procedures of the hip, provides favorable outcomes, although there are no reports of total hip arthroplasty being used to treat pseudoarthrosis of the periacetabular osteotomy segment. Therefore, we report a case of pseudoarthrosis in the osteotomy segment after periacetabular osteotomy. The patient was treated using modified total hip arthroplasty and achieved a favorable short-term outcome.Case presentationA 62-year-old Japanese woman was diagnosed with bilateral acetabular dysplasia at the age of 50 years, and underwent right and left periacetabular osteotomy at the ages of 52 and 55 years, respectively. When she was 61-years old, she experienced repeated episodes of left coxalgia during walking, with increasing pain at rest, and subsequently visited our department. Plain radiography and computed tomography of her left hip joint confirmed pseudoarthrosis of the periacetabular osteotomy segment. In addition, narrowing of her left hip joint space was observed, which indicated advanced osteoarthritis of the hip. Therefore, she underwent left total hip arthroplasty when she was 62-years old. During the surgery, fibrous fusion of the periacetabular osteotomy segment was confirmed via fluoroscopy, although no abnormal mobility was observed. Thus, the osteotomy segment was fixed with one absorbable screw and two bone pegs (which were prepared using allogeneic bone), and the acetabular cup was fixed using cement. Her postoperative course was generally favorable and bone fusion of the periacetabular osteotomy segment was confirmed at 3 years and 6 months after surgery. Her modified Harris hip score was 43 before the surgery and had improved to 90 at the final follow-up.ConclusionsModified total hip arthroplasty was successfully used to treat osteoarthritis of the hip and pseudoarthrosis of the periacetabular osteotomy segment. This procedure achieved pseudoarthrosis region bone fusion and a favorable postoperative outcome.

Acetabular labral tear complicating idiopathic osteonecrosis of the femoral head treated by labral repair with hip arthroscopy: A case report

IntroductionIt has been well documented that labral tear is frequently associated with femoroacetabular impingement and dysplasia of the hip; however, there have been few reported cases of labral tear associated with idiopathic osteonecrosis of the hip. Here we report the case of a patient with labral tear associated with idiopathic osteonecrosis of the femoral head who was treated by hip arthroscopy, with a favorable short-term outcome.Case presentationUnder the diagnosis of systemic lupus erythematosus, a 28-year-old Japanese woman was treated with the oral administration of steroid in 2007. A year after the treatment, she developed right hip joint pain and was diagnosed with idiopathic osteonecrosis of the femoral head at our institution. In November of 2011, she revisited our hospital when her right hip joint pain exacerbated and she became unable to walk. On the visit, the anterior impingement sign and Patrick test were positive. Radiography and magnetic resonance imaging in 2011 demonstrated neither spreading of the osteonecrosis area nor collapse of the femoral head in the right joint; however, magnetic resonance imaging showed a high-intensity area in the articular labrum in a T2-weighted image, leading to a diagnosis of labral tear. She underwent labral repair with hip arthroscopy in August of 2012. Now, 1 year after surgery, she does not feel any pain during walking and her modified Harris hip score has improved from 20 prior to surgery to 85.ConclusionThe case indicated that it is important to be aware of the possibility of labral tear in patients with idiopathic osteonecrosis of the femoral head, when spreading of the osteonecrosis area or collapse of the femoral head has not been seen on magnetic resonance imaging.