Platelet-rich plasma (PRP), a platelet concentrate made of autogenous blood, has been used to improve bone and soft tissue defect healing in recent years. The aim of this study was to assess the effect of PRP on articular cartilage defects in a rabbit model. Forty-eight osteochondral defects created in the femoropatellar groove were (a) left untreated, (b) treated with autogenous PRP in a polylactic-glycolic acid (PLGA), or (c) with PLGA alone. Platelets were enriched 5.12-fold compared to normal blood in the PRP. After four and 12 weeks, the explanted tissue specimens were assessed by macroscopic examination, micro-computed tomography, and histological evaluation. Macroscopic examination, micro-computed tomography and histology of the newly formed cartilage and bone in the defect differ significantly between the PRPtreated and the untreated groups, and stimulatory effect of PRP on osteochondral formation was observed. In conclusion, PRP in PLGA improves osteochondral healing in a rabbit model.

Free vascularised fibular grafting has been reported to be successful for adult patients with osteonecrosis of the femoral head (ONFH). However, its benefit in teenage patients with post-traumatic ONFH has not been determined. We evaluated the effectiveness of free vascularised fibular grafting in the treatment of this condition in children and adolescents. We retrospectively analysed 28 hips in 28 patients in whom an osteonecrotic femoral head had been treated with free vascularised fibular grafting between 2002 and 2008. Their mean age was 16.3 years (13 to 19). The stage of the disease at time of surgery, and results of treatment including pre- and post-operative Harris hip scores, were studied. We defined clinical failure as conversion to total hip replacement. All patients were followed up for a mean of four years (2 to 7). The mean Harris hip score improved from 60.4 (37 to 84) pre-operatively to 94.2 (87 to 100) at final follow-up. At the latest follow-up we found improved or unchanged radiographs in all four initially stage II hips and in 23 of 24 stage III or IV hips. Only one hip (stage V) deteriorated. No patient underwent total hip replacement. Free vascularised fibular grafting is indicated for the treatment of post-traumatic ONFH in teenage patients.

Our aim was to compare polylevolactic acid screws with titanium screws when used for fixation of the distal tibiofibular syndesmosis at mid-term follow-up. A total of 168 patients, with a mean age of 38.5 years (18 to 72) who were randomly allocated to receive either polylevolactic acid (n = 86) or metallic (n = 82) screws were included. The Baird scoring system was used to assess the overall satisfaction and functional recovery post-operatively. The demographic details and characteristics of the injury were similar in the two groups. The mean follow-up was 55.8 months (48 to 66). The Baird scores were similar in the two groups at the final follow-up. Patients in the polylevolactic acid group had a greater mean dorsiflexion (p = 0.011) and plantar-flexion of the injured ankles (p < 0.001). In the same group, 18 patients had a mild and eight patients had a moderate foreign body reaction. In the metallic groups eight had mild and none had a moderate foreign body reaction (p < 0.001). In total, three patients in the polylevolactic acid group and none in the metallic group had heterotopic ossification (p = 0.246). We conclude that both screws provide adequate fixation and functional recovery, but polylevolactic acid screws are associated with a higher incidence of foreign body reactions.

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A Raman scattering study of the vibrational modes in K 2 Al 2 B 2 O 7 crystals has been performed at room temperature. The vibrational modes are classified by the nuclear site group analysis method and the internal vibrational modes are assigned to vibrations of the BO 3 triangle and AlO 4 tetrahedron.

Skutterudite Na1+ x Fe4P12 whiskers were prepared by a new hydrothermal reduction alloying method. The diameter of the whisker is about 0.5−4 μm and its L/D ratio is about 10−20. Heating temperature and time can control the diameter and length of the skutterudite whisker. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), electronic diffraction (ED), and X-ray fluorescence analysis have been employed to characterize the products. XRD and ED revealed that the whiskers obtained at 200 °C are cubic skutterudite with a = 7.7995 Å. X-ray fluorescence analysis proved that there are sodium atoms in the skutterudite structure. The possible formation mechanism of Na1+ x Fe4P12 is proposed.

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Preparation of Na 1+x Fe 4 P 12 Whiskers by Hydrothermal Reduction Alloying Synthesis Method.-Whiskers of the title compound are prepared by a new hydrothermal reduction alloying method from FeCl 3 ·6H 2 O, NaOH, white phosphorus, and H 2 O (stainless steel autoclave, 200-240 • C, 15-40 h). The samples are characterized by XRD, SEM, and TEM. The diameter of the whiskers is about 0.5-4 µm and their L/D ratio is about 10-20. The whisker obtained at 200 • C is cubic skutterudite containing Na atoms. A possible formation mechanism is proposed. -(LIU, H.; WANG, J. Y.; HU, X. B.; GU, F.; HUA, L.; ZHANG, C. Q.; TENG, B.; CUI, D. L.; PAN, J. Q.; Chem. Mater. 13 (2001) 1, 151-154; Inst. Cryst. Mater., Shandong Univ.,