Poly lactic acid polymers are biodegradable, having long and strong strands of polymer, when water reaches them they decompose to acids exist in the human body. These polymers, instead of platinum, are used as holding for broken bones. After the bones repair, the polymer decomposes and excreted from the body as water and carbon dioxide, so it is no need for surgery re-operation. The main goal of this study was investigation of degradation mechanism, decomposition time and its effective factors. In this paper decomposition kinetic of biodegradable polymers in human body was studied, which is complicated due to its autocatalytic nature. The governing equations with boundary and initial conditions were solved numerically. Variation of product concentration, concentration of polymer bands and water were presented against exposure time. The time needed for complete decomposition was calculated equal to 11 months. Diffusion coefficients, water concentration and geometry affect the degradation process. Finally, recommendations for optimum use of these materials were presented.

The principles and limitations of current imaging modalities are described. It may help to determine the most effective radiologic technique, minimizing the cost of examination as well as the exposure to radiation. It is important to choose the appropriate mo-duality for specific types of orthopedic abnormalities. It is important to reemphasize that conventional radiography remains the most effective tool for demon-starting a bone and joint abnormality. Use of radiological techniques differs in evaluating the presence, type, and extent of various bone, joint, and soft-tissue abnormalities. Therefore, both the radiologist and orthopedic surgeon must know the in-dictation for use of each technique, the limitations of a particular modality, and the appropriate imaging approaches for abnormalities at specific sites. The question; "what modality should I use for this particular problem?" is frequently asked by radiologists and or-thopedic surgeons. Although numerous algorithms are available to evaluate various problems at different anatomic sites, the answer cannot always be clearly stated. The choice of techniques for imaging bone and soft-tissue abnormalities is dictated not only by clinical presentation, but also by equipment availability, ex-parties, and cost. Restriction may also be imposed by the needs of individual patients. Most of the time, the choice of imaging technique is dictated by the type of suspected abnormality. The purpose of this study was to review imaging techniques in ORTHOPEDICS.

With the expansion of medical knowledge, various new disciplines and subspecialties have been developed and trained for the comprehensive management of diseases. There is always an inevitable correlation between medical disciplines that cannot be completely separated from each other. Some diseases involve multiple organs/systems of the human body simultaneously, requiring the cooperation of a team of specialists to manage them. In addition, in some cases, there is an overlap between different specialties in managing and treating the same disease. Although specialists aim to give the patient the best possible treatment options, this overlap can lead to confusion in management according to different practice guidelines (1).

The present study was designed to assess analgesic effects of propofol on ORTHOPEDICS day surgeries. 150 adult patients undergoing ORTHOPEDICS day surgeries were randomly divided into 3 groups and allocated to receive either propofol, ketamine or  thiopenal for induction and maintaining anesthesia, after premedication by 1 µg/kg of fentanyl. To evaluate pain and to detect painful stimulation, parameters such as heart rate, systolic and diastolic arterial blood pressure, respiratory rate, pupil size, perspiration, muscle movement, awareness in recovery room, recall during surgery and satisfaction from anesthesia were used. Changes in these parameters were significantly greater in propofol group. We concluded that propofol does not have analgesic effects during anesthesia and must be accompanied by an analgesic like fentanyl or alfentanil and can be used by intravenous bolus method.