Redesign of Indonesian-made osteosynthesis plates to enhance their mechanical behavior.

Mechanical properties determined by fatigue strength, ductility, and toughness are important measures for osteosynthesis plates in order to tolerate some load-bearing situations caused by muscle contractions and weight-bearing effects. Previous study indicated that Indonesian-made plates showed lower mechanical strength compared to the European AO standard plate. High stress under load-bearing situations often starts from surface of the plate; we therefore refined the grain size of the surface by using shot peening and surface mechanical attrition treatment (SMAT). Single cycle bending tests showed that shot-peened and SMAT-treated plates had significantly higher load limit and bending stress compared to the original plates (p<0.05). Weibull analysis confirmed the improvement of proportional load limit of SMAT-treated plates. Fatigue limit also increased upon shot-peening and SMAT treatment (improvement ratio 18% and 27%, respectively). Significant improvement ratio of fatigue tests can be observed in SMAT-treated plates compared to the untreated and shot-peened plates. Fatigue performance demonstrated equivalent results between SMAT-treated and standard plate. These designated that mechanical properties of Indonesian-made plates can be improved upon SMAT treatment leading to significant enhancement of mechanical strength thus is comparable to the standard plate. Our findings highlight the benefits of SMAT treatment to improve mechanical strength of Indonesian-made osteosynthesis plates.

Deep Vein Thrombosis in Elderly Patients following Surgery for Fracture of the Proximal Femur.

The incidence of Deep Vein Thrombosis (DVT) is high in orthopaedic cases, associated with morbidity and mortality. This study was done to evaluate the incidence of DVT and factors that contributed to DVT in elderly patients with proximal femur fracture who underwent surgery. Patients 60 years of age and older with proximal femur fracture who underwent surgery were enrolled into this study. Daily observation of the clinical signs of DVT was done post operatively until the subjects were discharged from the hospital. D-Dimer test and contrast venography were carried out on Day 2 and between Days 4 and 7 after surgery. Results were interpreted as normal and obstruction. There were 42 eligible patients, 18 of them (42.86 %) were diagnosed with DVT. We found that positive D-Dimer test (1.40), longer duration of surgery (1.86), and presence of clinical symptoms (1.09) increased the risk of the occurence of thrombosis although not statistically significant. There were four DVT patients who passed away within 4 months after surgery due to complication from DVT. The incidence of DVT in elderly with proximal femur fracture underwent surgery was relatively high (42.86 %) with the mortality rate was 22%.

Mechanical properties of Indonesian-made narrow dynamic compression plate.

Osteosynthesis plates are clinically used to fixate and position a fractured bone. They should have the ability to withstand cyclic loads produced by muscle contractions and total body weight. The very high demand for osteosynthesis plates in developing countries in general and in Indonesia in particular necessitates the utilisation of local products. In this paper, we investigated the mechanical properties, i.e. proportional limit and fatigue strength of Indonesian-made Narrow Dynamic Compression Plates (Narrow DCP) as one of the most frequently used osteosynthesis plates, in comparison to the European AO standard plate, and its relationship to geometry, micro structural features and surface defects of the plates. All Indonesian-made plates appeared to be weaker than the standard Narrow DCP because they consistently failed at lower stresses. Surface defects did not play a major role in this, although the polishing of the Indonesian Narrow DCP was found to be poor. The standard plate showed indications of cold deformation from the production process in contrast to the Indonesian plates, which might be the first reason for the differences in strength. This is confirmed by hardness measurements. A second reason could be the use of an inferior version of stainless steel. The Indonesian plates showed lower mechanical behaviour compared to the AO-plates. These findings could initiate the development of improved Indonesian manufactured DCP-plates with properties comparable to commonly used plates, such as the standard European AO-plates.

Surface properties of Indonesian-made narrow dynamic compression plates.

The enormous need of orthopaedic (surgical) implants such as osteosynthesis plates is difficult to be fulfilled in developing countries commonly rely on imported ones. One of the alternatives is utilization of local resources, but only after they have been proven safe to use, to overcome this problem. Surface properties are some of the determining factors of safety for those implants. We have succeeded in developing prototype of osteosynthesis plate and the results indicate that Indonesian-made plates need improvement with regards to the surface quality of physical characterization.