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In recent years, significant developments have taken place in scientific fields such as tissue and materials engineering, which allow for the development of new, intelligent biomaterials. An example of such biomaterials is drug delivery systems that release the active substance directly at the site where the therapeutic effect is required. In this research, polymeric materials and ceramic-polymer composites were developed as carriers for the antibiotic clindamycin. The preparation and characterization of biomaterials based on hyaluronic acid, collagen, and nano brushite obtained using the photocrosslinking technique under UV (ultraviolet) light are described. Physical and chemical analyses of the materials obtained were carried out using Fourier transform infrared spectroscopy (FT-IR) and optical microscopy. The sorption capacities were determined and subjected to in vitro incubation in simulated biological environments such as Ringer's solution, simulated body fluid (SBF), phosphate-buffered saline (PBS), and distilled water. The antibiotic release rate was also measured. The study confirmed higher swelling capacity for materials with no addition of a ceramic phase, thus it can be concluded that brushite inhibits the penetration of the liquid medium into the interior of the samples, leading to faster absorption of the liquid medium. In addition, incubation tests confirmed preliminary biocompatibility. No drastic changes in pH values were observed, which suggests that the materials are stable under these conditions. The release rate of the antibiotic from the biomaterial into the incubation medium was determined using high-pressure liquid chromatography (HPLC). The concentration of the antibiotic in the incubation fluid increased steadily following a 14-day incubation in PBS, indicating continuous antibiotic release. Based on the results, it can be concluded that the developed polymeric material demonstrates potential for use as a carrier for the active substance.

We report on the stabilization of inherently unstable counterpropagating photorefractive spatial solitons by the use of one- and two-dimensional photonic lattices. We numerically investigate the dependence of the instability dynamics on period and amplitude of the lattice and present experimental verification for the dynamic stabilization of the bi-directional soliton state.

We experimentally generate different types of two-dimensional self-trapped photonic lattices in a photorefractive medium and analyze the induced refractive index change using two different methods. One method gives the first experimental Fourier space analysis of both linear and nonlinear self-trapped photonic lattices with periodic phase modulation using partially spatially incoherent multiband excitation of the lattice modes. The other method utilizes the waveguiding properties of the lattice to achieve a real space analysis of the induced refractive index change. The results of both methods are compared.

We predict theoretically and generate in a photorefractive crystal two-dimensional self-trapped periodic waves of different symmetries, including vortex lattices-patterns of phase dislocations with internal energy flows. We demonstrate that these nonlinear waves exist even with anisotropic nonlocal nonlinearity when the optically-induced periodic refractive index becomes highly anisotropic, and it depends on the orientation of the two-dimensional lattice relative to the crystallographic c-axis.

We generate experimentally different types of two-dimensional Bloch waves of a square photonic lattice by employing the phase imprinting technique.We probe the local dispersion of the Bloch modes in the photonic lattice by analyzing the linear diffraction of beams associated with the high-symmetry points of the Brillouin zone, and also distinguish the regimes of normal, anomalous, and anisotropic diffraction through observations of nonlinear self-action effects.

We demonstrate theoretically and experimentally a novel type of localized beam supported by the combined effects of total internal and Bragg reflection in nonlinear two-dimensional square periodic structures. Such localized states exhibit strong anisotropy in their mobility properties, being highly mobile in one direction and trapped in the other, making them promising candidates for optical routing in nonlinear lattices.

We analyze theoretically and generate experimentally two-dimensional nonlinear lattices with periodic phase modulation in a photorefractive medium. The light-induced periodically modulated nonlinear refractive index is highly anisotropic and nonlocal, and it depends on the lattice orientation relative to the crystal axis. We discuss the stability of such induced photonic structures and their guiding properties.

We discuss the creation of an array of 9 x 9 photorefractive spatial screening solitons in a strontium barium niobate crystal. We investigate the waveguide properties of each channel with a beam of different wavelength and find that the waveguides guide the probe beam independently. A supplementary beam is used to influence the paths of the array solitons and to effectively combine two channels by use of mutual attraction of solitons. To our knowledge this is the first all-optical control of an array of photorefractive solitons. Furthermore, we show that in principle image procession is possible with parallel propagation of photorefractive solitons.

The risks associated with blood transfusion can be minimized using autologous blood. The efficiency of preoperative blood deposit, preoperative acute-hemodilution spinal anesthesia, controlled hypotension and intra and postoperative autotransfusion in reducing homologous transfusion has been demonstrated. In a prospective study the effectivity of this concept is demonstrated. 141 patients scheduled for total hip arthroplasty were divided in three groups: group I--total hip arthroplasty without cement (n = 55); group II--total hip arthroplasty with cement (n = 52); and group III total hip revision arthroplasty (n = 34). The mean quantity of the donated blood was 900 mL. The donation was not associated with serious complications. In group I 52 patients (94.5%), in group II 40 patients (77%) and in group III 14 patients (41.2%) did not require homologous transfusion. The difference between group I and II was significant (p < 0.05). Under the conditions studied, preoperative autologous blood deposit, acute hemodilution, spinal anesthesia and controlled hypotension are effective for decreasing the application of homologous transfusions in hip arthroplasty. The efficiency of preoperative hemodilution alone is limited. Preoperative deposit of autologous blood is a simple, effective, economical, and low-risk method of reducing homologous transfusion. Autotransfusion with a cell separator can save approximately 50% of the erythrocytes lost during revision total hip arthroplasty.

5-9 years follow-up results following 26 out of 37 operated injuries of the ligaments of the knee are reported. While 18 patients described the result of the operation as very good and good, the objective findings presented only 5 stable knees.

Analysis of 100 consecutive arthroscopies in patients with traumatic hemarthrosis of the knee joint demonstrates the importance of arthroscopy in diagnosis and therapy. In 48 cases injuries of the anterior cruciate ligament, isolated and in combination with lesions of other structures, were found. In 47 cases an operation was necessary. In 21 cases the reason for the hemarthrosis was luxation of the patella, in 6 cases with a flake fracture. Isolated lesions of one of the menisci were found in 11 cases and treated arthroscopically in all cases (2 meniscopexies, 1 total meniscectomy , 8 partial meniscectomies). Only in 8 cases unimportant injuries or lesions were found to have caused the hemarthrosis.

From June 1976 to June 1981, 71 isoelastic total hip endoprostheses were implanted. In a 5-to 7-year follow-up study, all but one of the hips that had been operated upon could be evaluated. In 10 cases reoperation was performed because of loosening of the stem (3 infections, 7 aseptic loosenings). In the remaining 51 endoprostheses in 45 patients, 2 were described as in poor shape. In 3 cases, an X-ray film demonstrated potential loosening of the stem. Because there is a 9.8% loosening rate of the stem, the indication for implantation has been restricted. We had no problems at all with the RM acetabular components.

Ender-nailing is a proved method in the treatment of sub- and pertrochanteric fractures in old people. In special cases Ender-nailing can be useful in the treatment of other types of fractures. 3 cases of Ender-nailing of femoral shaft fractures in childhood are reported.

It is reported in two cases of synostosis of the vertebral which is related in the Medical literature as "Dysontogenetic blockbuilding of the Corpus Vertebrae". This condition could be seen in a 13 year old boy in the area of Th 9 to Th 12 and in a 13 year old girl from Th 11 to L1. The clinical and radiological findings of these two cases will be described and discussed. An attribution of these cases to the "Dysontogenetic blockbuilding" groups was based on a disturbance of the vertebral forming. A causal therapy is not possible.

This is a report on findings of an ulna defect in a small girl, due to a haematogenous infection in her right arm, which was successfully treated and healed with a bone graft using a portion of the 6th rib. The last x-ray examination, three years after the operation, showed a definite consolidation of the rib ulna transplantation and clinically good mobility of the elbow joint and underarm.

Since June 1979 we implant the RM isoelastic total hip endoprosthesis in younger patients (average age 53 years). Up to now 391 endoprostheses have been implanted. A follow-up examination of 60 operated hips in 55 patients 3 and 4 years after the implantation of the endoprosthesis was possible. In 46 hips there was no pain at all, in 12 hips a light or medium pain and in 2 hips a severe pain. 35 hips showed a range of motion of more than 90 degrees and between 30 degrees and 90 degrees. All patients were able to walk, 37 patients more than 1 hour. The patients declared the results of the operation in 50 hips to be very good or good, in 4 hips to be fair and in 6 hips to be poor. 5 times a potential loosening of the stem could be found.

17 patients with chronic fibular instability of the ankle had been operated on using autologous corium for reconstruction. Follow up examinations on an average of 1 year are reported; advantages and disadvantages of the operation technique are described.

It is reported about a young girl with congenital agenesis of the os sacrum, a congenital platfoot and a luxation of the left hip. These congenital malformations can be found in children born to diabetic mothers.

In 11 cases an arthrosis of the knee joint was treated by intraosseus osteotomy of the distal femur in one case of the proximal tibia only; in one case additionally an intraosseus osteotomy of the proximal tibia was performed. In a 2 to 5 years follow-up examination only 4 patients were subjectively satisfied with the operation.

The operation technique of the V-Y correction in varus deformity of the fifth toe and the necessity of a correct technique is demonstrated. 16 patients who had been operated on by this procedure could be followed up. In 11 patients good results were to be seen.

A case of the rare Freeman-Sheldon Syndrome combined with a high luxation of the left hip is reported. The importance of differential diagnosis to arthrogryposis multiplex congenita is explained.

Hemangiopericytomas are very rare tumors that mostly develop in the soft tissues. In rare cases, however, they may occur as primary bone tumors which are extremely rare. In case of such an intraosseous tumor, a bone metastasis of such a soft tissue sarcoma must be considered first and has to be excluded. In a 62 year old female, a hemangiopericytoma of the left femoral neck was diagnosed that had induced a pathological bone fracture. A resection of the femoral head and neck was performed. Anamnestical investigations, however, have shown that 4 years before, such a tumor of the pelvic soft tissues was removed. Thus, the lesion of the femoral neck had to be classified as bone metastasis of a malignant hemangiopericytoma. It has to be emphasized that this special tumor always shows a questionable prognosis and, by histological investigations, it cannot be decided if we are dealing with a benign or malignant tumor growth. Diagnostic managements and clinical problems with hemangiopericytomas are discussed in detail.

It is reported about follow-up examinations in 26 patients with chronic fibular instability of the ankle, who had been operated on using the Watson-Jones and Evans technique. 19 Patients described the results as excellent or good, 7 patients as fair, 22 patients would agree to undergo an operation in the same technique again.

It is reported about hypertrophy of the nuchae ligament in an 28 year old woman. After operation (extirpation) the mobility of the cervical spinal column was nearly free and the permanent headache of the patient had gone.

It is reported of 77 patients with fractures of the proximal femur who have been treated with internal fixation using Ender-nails. The average age was 76 years. The mortality rate was 16.9%, the infection rate 2.6%. In 79.2% there were no complications at all. The average hospitalisation period was 35 days. After an average period of 2 1/2 years a follow-up study was possible (24 patients). In 62.5% there was no pain, in 25% patients had light pain in the knee and in 8.3% they felt light pain in the hip. An important disturbance of movements in hip or knee was never to be seen. Only one patient was not able to walk. 58.3% walked without help, 37.5% with the help of a walking stick. In 54.2% there was a rotation failure of the femur, in 25% more than 20 degrees.

A problematic case of pyoderma gangraenosum in a patient with colitis ulcerosa mimicing an empyema of the knee joint is reported.