Dissimilar Materials Welding with a Standoff-Free Vaporizing Foil Actuator between TRIP 1180 Steel Sheets and AA5052 Alloy.

This paper mainly demonstrates an advanced type of the vaporizing foil actuator welding (VFAW) process between GPa-grade steel (TRIP1180) and aluminum alloy (AA5052-H32) without applying standoff. To secure a flying distance during the VFAW process, the preformed target sheet shaped like a circular indentation has been utilized. It is necessary to optimize process parameters integrated with geometrical design of the preform since the welding strength can be decreased beyond the optimum input energy in the standoff-free VFAW process. The welded surface was evaluated by SEM-EDS, XRD, EBDS, and TEM to analyze the welding mechanism and composition at the welding interface. The diffusion zone including the AlFe3 phase was observed at the welded interface which has high grain density due to the high-speed impact by increasing the welding strength, which leads to the perfect welding between the dissimilar materials.

Mid-Term Follow Up Results of Subtalar Distraction Arthrodesis Using a Double Bone-Block for Calcaneal Malunion

PURPOSE: This study was designed to evaluate the mid-term results and efficacy of subtalar distraction double bone-block arthrodesis for calcaneal malunion. MATERIALS AND METHODS: From January 2004 to June 2007, we operated on 6 patients (10 cases). There were 5 males (9 cases) and 1 female (1 case), four of which presented with bilateral calcaneal malunion. Seven cases were operated on initially. The period between initial injury and arthrodesis was 23 months, and the average follow up period was 58 months. In operation, we applied an extensile lateral approach and arthrodesis was performed through a tricortical double bone-block and cannulated screws. The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale was used for clinical evaluation. In radiologic analysis, plain X-ray and CT were examined to assess union and various parameters. RESULTS: The mean age of the patients was 41 years. All cases achieved radiologic union at the final follow-up. The mean AOFAS Ankle-Hindfoot scale (maximum of 94 points) increased from 43.3 points preoperatively to 85.4 points at the final follow-up. The radiologic analysis of the pre- and postoperative standing lateral radiographs showed improvements of 5.6 mm in talo-calcaneal height, 1.8degrees in talocalcaneal angle, 5.1degrees in talar declination angle and 5.3degrees in talo-first metatarsal angle. CONCLUSION: Subtalar distraction two bone-block arthrodesis provides overall good results not only in the short term but also the mid-term with significant improvement in clinical and radiologic outcomes. This procedure warrants consideration for managing calcaneal malunion with loss of height and subtalar arthritis.

Clinical Outcomes of Combinations of Locking Compression Plate Fixation through Minimally Invasive Precutaneous Plate Osteosynthesis and Interfragmentary Screw Fixation in Distal Tibia Fracture / 대한족부족관절학회지

PURPOSE: To analyze the outcome of distal tibia fracture treated with the Distal Tibia LCP with combination of interfragmentary screw. MATERIALS AND METHODS: Between January 2008 and March 2012, data of 34 patients with fracture of distal tibia treated with the Distal Tibia LCP with or without combination of interfragmentary screws were reviewed. There were 17 males and 17 females with an average age of 51.8 years (range, 18~77 years). Radiographic union time and time from surgery until ability to full weight bearing were measured and compared. Callus index was measured as quotient of callus thickness and diameter of corticalis both in AP and sagittal direction. RESULTS: 12 fractures were treated with interfragmentary screws and 22 fractures were treated with bridging plate alone. In interfragmentary fixation group, time to full weight bearing was 14 weeks versus 15.75 weeks without screw. Callus index at bearing was not significantly lesser in patients with screw compated with those without, but callus index difference at posterative 4weeks was sigficant. Radiologic union time was 11.3 weeks in interfragmentary fixation group and 12.58 weeks without screw. CONCLUSION: The osteosynthesis with the Distal tibia LCP with combination of interfragmentary screw seems to be more stable in postoperative 4weeks than Distal tibia LCP alone, expecting to earlier ROM exercise and rehabilitation.

Comparison of Adjacent Spinal Compression Fracture after Old Osteoporotic Spinal Compression Fracture and Percutaneous Vertebroplasty / 대한골다공증학회지

OBJECTIVES: New adjacent spinal compression fractures occur not only in patients with osteoporotic spinal compression fractures after vertebroplasty but also in untreated old spinal compression fractures. The objective was to analyze and compare the characteristics in a group who had untreated old osteoporotic spinal compression fractures with those who had adjacent spinal compression fractures, which occurred after a vertebroplasty. MATERIALS & METHODS: From April 2006 to April 2009, 103 patients who had undergone vertebroplasty were evaluated. Eighteen patients (22 cases) who had untreated old osteoporotic spinal compression fractures were in group I, and 12 patients (13 cases) who had adjacent spinal compression fractures, which occurred after a vertebroplasty were in group II. In each group, we measured age and gender, body mass index (BMI), lumbar bone marrow density (BMD), sagittal index, and compression rate at the initial fracture site.

Effects of Recombinant Human Growth Hormone Treatment in Elderly Patients Undergoing Surgery for Hip Fracture / 대한정형외과연구학회지

PURPOSE: To investigate whether early recombinant human growth hormone (hGH) treatment in elderly patients undergoing surgery for hip fracture improves biochemical and functional recovery. MATERIALS AND METHODS: From September 2007 to December 2008, a total of 25 patients older than 60 years who underwent a gamma nailing surgery for an accidental hip fracture were randomized to be treated with either hGH (Declage(R), 3mg/week) (Group I: 15 patients) or placebo (Group II: 10 patients) at a postoperative 1, 2, 3 weeks, starting within 24 hour after the hip fracture. Mean age was 73.5 years. 6 cases were male and 19 cases were female. Serum IGF-I was measured by radioimmunoassay. Subjective and objective parameters were analyzed such as the mean mid-thigh circumference, change of weight, hand grip strength, functional recovery by Modified Barthel Index of activities of daily living (ADL). RESULTS: There were significant differences in the mean serum IGF-I, mid-thigh circumference, hand grip strength, Modified Barthel Index of activities of daily living between two groups. There were no significant differences in the change of weight. There were three nausea symptom after hGH injection, but no any general adverse effect. CONCLUSION: Early recombinant human growth hormone (hGH) treatment in elderly patients undergoing surgery for hip fracture showed clinical safety and good biochemical and functional recovery.