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The evolution of surgical approaches and procedures over the past century is remarkable. The brutality and risks associated with operations has substantially decreased, whereas the procedures themselves became safe and efficient. Nevertheless, none of the surgical procedures is completely safe, reliable and painless, which often leads to the patients experiencing post-operative discomforts. These discomforts are usually resolved within several days after the operation, and do not require any additional prophylaxes or treatments. However, in some cases, surgeries are followed by post-operative complications that cannot be resolved without additional medical attention. Shock, hemorrhage, deep vein thrombosis, pulmonary complications, urinary retention, reaction to anesthesia are among the most devastating post-surgical complications. However, the most important ones are infections and chronic pain. The emergence of these complications becomes more acute when surgical implants are used during the operation. Implant-associated complications often require specific medical treatment; in some cases, additional surgery or implant removal is necessary to resolve the complication. All these negatively affect patients' quality of life and put an additional economic pressure on a healthcare system. Therefore, the development of approaches to decrease the burden of surgical implant-associated complications, in particular chronic pain and infections, is an important objective and was addressed in the present study. The first part of the dissertation is focused on the post-surgical infections. We addressed this problem in the example of orthopaedic Kirchner wires, bearing in mind high incidence rate of the pin-site infections, which can reach up to 100% for longer implant residence times. Therefore, novel approaches to prevention of microbial infections after insertion of orthopedic external fixators are in great demand. Monolaurin is an antimicrobial agent with known safety record, broadly used in food and cosmetic industries; however, its use in antimicrobial coatings of medical devices has not been studied in much detail. Here, we report the use of monolaurin as an antibacterial coating on external fixators for the first time. The monolaurin-coated Kirschner wires (K-wires) showed excellent antibacterial properties against three different bacterial strains - Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis. Both planktonic and adherent bacteria were completely eliminated, when brought in contact with monolaurin-coated K-wires. At the same time, monolaurin-coated K-wires did not show any observable cytotoxicity with mouse osteoblast cell cultures. Overall, monolaurin-coated K-wires could be promising as potent antimicrobial materials for orthopaedic surgery. In the second part of the dissertation we address post-operative chronic pain in the example of hernia repair meshes. First, we focused on studying the mechanism of the development of post-hernioplasty chronic pain. Despite the relative safety of the procedure, hernia repairs are often associated with chronic post-operative pain. While this complication has been linked among others to mesh deterioration, details of the processes that lead this deterioration are still unknown. Here, we aimed to bridge this gap by analyzing the chemical, physical and structural alterations in hernia repair meshes exposed to oxidative stress in vitro. We developed a methodology to characterize effect of oxidation stress on structure and properties of polymeric hernia repair meshes. It was shown that structural changes in polypropylene meshes exposed to oxidative stress may involve formation of cross-links between the polymer chains, chain scissions, and hydrogen bonds between the carboxyl groups, which are formed in the material during the oxidation. These effects result in mesh stiffening, ultimately leading to chronic post-operative pain. Moreover, we demonstrated that Composix™ meshes are more vulnerable to the oxidative stress when compared with UltraPro® meshes. Consequently, we focused on coating polymeric hernia meshes with anti-inflammatory agents in an attempt to mitigate the oxidative stress and improve long-term outcomes of the surgery. In particular, polypropylene hernia repair meshes coated with vitamin E (-tocopherol), a known antioxidant, were prepared and characterized. The adsorption isotherm of vitamin E on the mesh was characterized and a release profile study yielded a promising results, showing sustained release of the drug over a 10-day period. An animal study was conducted, and histological analysis 5 weeks after implantation exhibited a reduced host tissue response for a modified mesh as compared to a plain mesh, as evidenced by a higher mature collagen to immature collagen ratio, as well as lower level of fatty infiltrates, neovascularization and fibrosis in the case of modified mesh. These results support the use of -tocopherol as a potential coating in attempt to reduce the extent of post-operative inflammation, and thereby improve long-term outcomes of hernioplasty.

An appraisal of the clinical records of patients with malignant bone tumours enabled us to identify 61 whom we have treated by external fixation. There were 38 males and 23 females with ages ranging from 4 to 58 years, the mean being 14 years. The average period of follow-up was 6 years (1-12 years). For the purpose of our analysis the patients were divided into three groups according to whether the fixator was fitted before, during or after tumour resection.

Monolateral frames were applied to five dogs and ten lambs for treatment of large segmental bone defects (LSBD) surgically induced in one of their femoral diaphyses. Reconstruction was attempted by bone transport, as developed by Ilizarov. Monolateral frames were used to minimize the draw-backs of Ilizarov's circular device. Radiographic, computed tomographic, and histologic studies were performed. The skin and soft tissues were not a major obstacle for the longitudinal migration of the screws during bone transport. Four months after the operations, healing and remodeling of the bone defect was always satisfactory. Histologically, the repair of the lengthened segment followed an intramembranous ossification pattern in its central areas and in the periphery as well. At the end of the experiment, the new induced bone had a virtually normal diaphyseal bone appearance. Bone transport for the treatment of experimental LSBD can be completed in monolateral frames.

We reviewed the results of distraction osteogenesis of 114 femora and 147 tibiae that had been lengthened to treat a variety of diagnoses. The femora had been lengthened an average of eleven centimeters (range, 3.5 to 17.0 centimeters), or 48 per cent (range, 8 to 86 per cent) of the original femoral length. The average total time for the treatment of the femora (use of the fixator and any subsequent immobilization) was 257 days (range, 105 to 420 days). There were 114 complications related to the femoral lengthenings, which led to eighty-seven additional operations. The tibiae were lengthened an average of nine centimeters (range, 3.0 to 15.6 centimeters), or 41 per cent (range, 9 to 100 per cent) of the original tibial length. The average total time for the treatment of the tibiae was 268 days (range, 110 to 497 days). There were 196 complications related to the tibial lengthenings, which led to 219 additional operations. The Achilles tendon was lengthened during or after seventy-three (50 per cent) of the tibial lengthenings. The femoral lengthenings that were performed to treat a limb-length discrepancy were associated with significantly higher rates of complications overall (p = 0.010) and additional operations (p = 0.023) for each percentage of length gained than those that were performed to treat achondroplasia or another skeletal dysplasia. The femoral lengthenings that were performed to treat short stature (of an endocrine or idiopathic etiology) were also associated with higher rates of complications overall and additional operations than those performed to treat skeletal dysplasias, but the rates were lower than those for lengthenings performed to treat limb-length discrepancy. The rate of complications overall associated with femoral lengthening in patients who were fourteen years old or more was significantly higher than that associated with lengthening in patients who were less than fourteen years old (p = 0.047). Femoral lengthening through the metaphysis was associated with significantly higher rates of complications overall (p = 0.031) and additional operations (p = 0.042) for each percentage of length gained than femoral lengthening through the diaphysis. The tibial lengthenings that were performed to treat Turner syndrome and idiopathic short stature were associated with significantly higher rates of complications overall (p = 0.026) and additional operations (p = 0.003) for each percentage of length gained than those performed to treat skeletal dysplasias. The rate of joint-related problems (p = 0.044) and that of additional operations (p = 0.053) after tibial lengthening in patients who were fourteen years old or more were significantly higher than those rates after tibial lengthening in patients who were less than fourteen years old. The site of the tibial osteotomy did not affect the rate of complications or additional operations. The femoral healing indices (in terms of both days per centimeter [p = 0.002] and days for each percentage of length gained [p = 0.019]) were significantly higher in the patients who were fourteen years old or more than in those who were less the fourteen years old. These values could not be used to predict an increase in the complications because of poor bone formation. The results of the present review suggest that the use of healing indices to gauge the final outcome of distraction osteogenesis is questionable; we were unable to discern significance or clinical importance from appropriately adjusted values.