Da-Hui Sun

Shockwaves Induce Osteogenic Differentiation of Human Mesenchymal Stem Cells Through ATP Release and Activation of P2X7 Receptors

Shockwave treatment promotes bone healing of nonunion fractures. In this study, we investigated whether this effect could be due to adenosine 5′‐triphosphate (ATP) release‐induced differentiation of human mesenchymal stem cells (hMSCs) into osteoprogenitor cells. Cultured bone marrow‐derived hMSCs were subjected to shockwave treatment and ATP release was assessed. Osteogenic differentiation and mineralization of hMSCs were evaluated by examining alkaline phosphatase activity, osteocalcin production, and calcium nodule formation. Expression of P2X7 receptors and c‐fos and c‐jun mRNA was determined with real‐time reverse transcription polymerase chain reaction and Western blotting. P2X7‐siRNA, apyrase, P2 receptor antagonists, and p38 MAPK inhibitors were used to evaluate the roles of ATP release, P2X7 receptors, and p38 MAPK signaling in shockwave‐induced osteogenic hMSCs differentiation. Shockwave treatment released significant amounts (∼7 μM) of ATP from hMSCs. Shockwaves and exogenous ATP induced c‐fos and c‐jun mRNA transcription, p38 MAPK activation, and hMSC differentiation. Removal of ATP with apyrase, targeting of P2X7 receptors with P2X7‐siRNA or selective antagonists, or blockade of p38 MAPK with SB203580 prevented osteogenic differentiation of hMSCs. Our findings indicate that shockwaves release cellular ATP that activates P2X7 receptors and downstream signaling events that caused osteogenic differentiation of hMSCs. We conclude that shockwave therapy promotes bone healing through P2X7 receptor signaling, which contributes to hMSC differentiation. STEM Cells 2013;31:1170–1180

Death Due to Intra-aortic Migration of Kirschner Wire From the Clavicle: A Case Report and Review of the Literature.

AbstractMigration of orthopedic fixation wires into the ascending aorta though a rare occurrence can have devastating consequences. Therefore, prompt recognition, with immediate and cautious retrieval of the implant is paramount in averting these complications.We present a case of a 5-year-old boy with the intra-aortic migration of a K-wire used for the treatment of a right clavicle fracture. He was transferred to us with a history of syncope, chest pain, and shortness of breath 7 days after K-wire placement, which was performed at another hospital. On CT scan, the wire was found to be partially inside the ascending aorta, which was associated with massive hemopericardium and cardiac tamponade. The patient was taken up for emergency surgery for the removal K-wire and for the management of cardiac temponade. However, the patient developed cardiac arrest during the induction of intravenous anesthesia and endotracheal intubation. The K-wire was retrieved from the thorax via thoracotomy. However, the patient died 10 days after the surgery.As the migration of wires and pins during orthopedic surgery can cause potentially fatal complications, these should be used very cautiously, especially for percutaneous treatment of shoulder girdle fractures. The patients with such implants should be followed frequently, both clinically and radiographically. If migration occurs, the patient should be closely monitored for emergent complications and the K-wire should be extracted immediately.

Shockwaves Inhibit Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Association with Adenosine and A2B Receptors

Extracorporeal shockwave therapy (ESWT) has emerged as the important choice for the treatment of many orthopedic disorders. Our previous mechanistic studies suggest that ESWT promoted osteogenesis of human mesenchymal stem cells (hMSCs) through mechanisms that involve adenosine 5′-triphosphate (ATP) release. In this study, we investigated the effect of ESWT on chondrogenesis of hMSCs. We demonstrate that ESWT treatment caused a significant release of adenosine from hMSCs; ESWT treatment increased the levels of A2B receptor (A2BR) in hMSCs under 3-D culture conditions. ESWT, exogenous adenosine and specialized A2BR agonist suppressed hMSC chondrogenic differentiation through downregulating the expressions of aggrecan (ACAN), Collagen Type I alpha 2(COL1A2), Collagen Type II alpha 1(COL2A1), Sex-Determining Region YBox 9 (SOX9) and Sex-Determining Region YBox 6 (SOX6). Selective A2BR antagonists induced chondrogenic differentiation of hMSCs. This study indicated that shockwave therapy inhibits hMSC chondrogenic differentiation through or partially through regulation of adenosine release and activation of A2B receptor under 3-D culture conditions.

Posterior dislocation of the hip with bilateral femoral fractures: An unusual combination.

Posterior hip dislocation with concomitant femoral fracture is very rare. Here, we report a rare case of a 43-year-old man who was injured in a car accident. The patient sustained right posterior hip dislocation with concomitant right acetabular transverse and posterior wall fracture, ipsilateral femoral shaft fracture, and contralateral proximal femoral fracture (AO type 31-A3). Closed reduction of the hip was attempted, but failed. The acetabular fracture and posterior hip dislocation were reduced and acetabular fracture was fixed using plates through the Kocher-Langenbeck approach. The ipsilateral femoral fracture was treated with closed reduction and intramedullary nailing. The contralateral femoral fracture was treated with closed reduction and Gamma 3 nailing. Postoperative X-rays revealed reduction of the fractures. The patient achieved bone union and recovered function of the hip 4 months after surgery.

Mechanical properties in the ovariectomized rat model of osteoporosis after continuous and intermittent vibration

High frequency and low magnitude mechanical signal is endorsed as a new approach in preventing osteoporosis. The model of osteoporosis was established by forty-two wistar ovariectomized rats aged six months. Following a eight-week protocal composed of continuous and intermittent vibration, all the rats were executed by manual cervical dislocation. Biomechanical properties were determined by three point bending test of left ulnas and compression test of left tibial compact and cancellous bone. It was shown that the high frequency and low magnitude stimuli would prevent osteoporosis and the best effect was obtained in the IVGIO.

Reconstruction of acetabular posterior wall fractures with extension to the roof using dual arc-shaped plates: A case report

Anatomical reduction and rigid fixation of acetabular posterior wall fractures extending to the acetabular roof proves challenging because of the big bony fragment and muscular obstruction to accessing this region. This report describes a novel reconstructive technique in a patient with an acetabular posterior wall fracture involving the acetabular roof. Both the standard Kocher-Langenbeck approach and a greater trochanter osteotomy technique were used. Following anatomical reduction, a dual arc-shaped reconstruction plate technique was employed to achieve rigid fixation. The patient recovered with satisfactory function at the injured hip. We recommend this dual arc-shaped reconstruction plate technique for the treatment of acetabular posterior wall fractures extending to the acetabular roof in clinical practice.

Vacuum sealing drainage therapy in the presence of an external fixation device: A case report

Rationale:Vacuum sealing drainage (VSD) is widely utilized for treating traumatic wounds. Patient concerns:It is particularly difficult and time consuming to use in combination with an external fixator. Diagnoses:This is because the hardware or pins used for fixation interfere with maintaining a seal, resulting in poor adhesion and subsequent air leakage. Interventions:To resolve this problem, we have devised a new method for sealing the wound dressing, while maintaining the required vacuum.When using this technique, a rubber strip is wrapped around each pin in 3 circles outside the plastic drape, and then tightly tied. Outcomes:After completing this procedure, a vacuum is obtained, and any air leakage stops. We employed this technique to treat a cohort of patients in our department over a period of two years, and obtained good healing of soft tissue without air leakage, as well as good clinical outcomes. Lessons:We have observed that patients treated with this method experienced good clinical outcomes without air leakage, and we recommend its use in treating cases where an external fixation device is present.

A novel technique to prevent guide wire related complications while inserting the 4.0 mm cannulated screws

BACKGROUND Cannulated screws (4.0 mm) provide inter-fragmentary compression and stability to fractures. A guide wire is used to define the screw trajectory and hold the fracture fragment while the screw is being inserted. The cannulated shaft typically accommodates a 1.25 mm guide pin. Since the guide pin is very slender and undergoes elastic deformation during insertion, there is a high probability of pin breakage. METHODS The authors have devised a new way to place the 4.0 mm cannulated screws in a manner that prevents the intraoperative complication of guide wire breakage. For this technique, predrilling was achieved using a 2.0 mm K-wire which was subsequently replaced with a 1.25 mm guide pin under the protection of sleeve. 4.0 mm cannulated screws were then inserted into a defined trajectory over the guide pin. RESULTS Using the technique, over 20 patients were managed in our department over a period of two years without any complications. CONCLUSION We have observed that patients treated with this method experience short operation time, combined with good clinical outcome and we recommend its use in cases where cannulated screw use is warranted.

A finite element analysis of mechanics about the long head of biceps brachii tendon

Object: There are several therapies for rupture of long head of biceps tendon, including biceps tenotomy. However, there is still a disagreement on it, because this procedure may change thebiomechanical properties of shoulder and lead to degeneration of rotator cuff. The purpose of this study is to determine the change of stress and strain on shoulder with or without biceps tendon when the joint is loaded by a particular stress. Methods: Based on the CT scan, established two finite element models of the shoulder by Mimics and ABAQUS software, namely with or without biceps tendon. Exerted loading to the modesl and analyzed the distribution of stress and strain. Results: There was a significant difference on the distribution of stress and strain in the two models. Conclusion: 1. The combination of CT scan data and Mimics can be used to set up a accurate three dimension shoulder model. The accuracy of the analysis result is addressed after providing an accurate material property to the model according to CT value and empirical formula.2. The LHBT tenotomy would not accelerate the degeneration of ratator cuff, because the stress of the distal attachment of supraspinatus on greater tuberosity did not increase after the procedure.