[Biocompatibility testing of different sterilised or disinfected allogenous bone grafts in comparison to the gold standard of autologous bone grafts--an "in vitro" analysis of immunomodulation]. / Biokompatibilitätstestung unterschiedlich sterilisierter bzw. desinfizierter allogener Knochentransplantate im Vergleich zum Goldstandard der autologen Knochenspende--Eine "In-vitro"-Analyse der Immunmodulation.

INTRODUCTION: Repair of large skeletal defects using bone allografts has become a routine procedure in orthopaedic and trauma surgery. Different procedures of sterilisation (82.5 degrees C disinfection; 121 degrees C autoclaving; PES; Tutoplast; 25 kGy gamma irradiation) are available to inactivate bacteria and fungi, including their spores, as well as viruses in human bone allografts. The efficiency of these procedures has been proven. However, the effects on the cellular response are rarely investigated. This present in vitro study investigates the immunological answer of human bone marrow cells to human allogenous and autologous bone platelets which were sterilised by different methods. MATERIALS AND METHODS: Human bone marrow cells and the bone platelets were harvested from patients undergoing a total hip replacement. All patients provided informed consent. Human bone platelets, 10 mm in diameter, 3 mm in height, were produced from femoral heads which were removed within the scope of total hip replacements. They were sterilised by different procedures or were disinfected (gamma radiotherapy, PES/ethanol treatment, Tutoplast procedure, 121 degrees C autoclaving, > 82.5 degrees C thermodisinfection). In addition, an autologous in vitro bone donation was simulated and compared with the allogenous bone grafts. Endobon was evaluated as a bovine hydroxyapatite ceramic. As control a human bone marrow cell culture without bone platelets was used. Over a period of four weeks the changes of the immunogenic cell populations were analysed in vitro (FACS analysis). Light and scanning microscopy were done to reveal morphological differences. As a vitality test the trypan-blue staining was performed. RESULTS: Light and scanning microscopy demonstrated large differences between the various sterilisation and disinfection methods. After 4 weeks the autologous bone platelets were completely covered with homogenously distributed human osteoblast like cells. The heat-sterilised/disinfected transplants demonstrated similar effects compared to the autologous bone grafts while the irradiated bone platelets demonstrated less cell coverage. 2/3 of the cells were vital on average after four weeks, with the exception of the irradiated bone platelets. The FACS analysis revealed in comparison to the control group provable differences in the immunological answer for the autologous bone donation as well as for the differently sterilised or disinfected allogenous bone grafts. The heat sterilisation or, respectively, disinfection methods compared to the autologous bone donation demonstrated almost similar in vitro effects. By far the worst results, characterised by an excessively increased portion of cytotoxic T-cells and a decreased amount of viable cells, were seen in the 25 kGy gamma irradiation samples. CONCLUSIONS: The results demonstrate the influence of the different sterilisation and disinfection procedures on the differentiation of human marrow cells (host). Similar in vitro effects were seen for the autologous and heat-treated bone platelets. The treatment of allogenous bone grafts with PES/ethanol and the Tutoplast procedures showed, just as Endobon, only low differences in comparison with the control cultures. The worse results in the case of the irradiated bone platelets may be explained by the production of free radicals which led to an excessive cell death.

[Inactivation of HIV-1 in human femur heads using a heat disinfection system (Lobator SD-1)]. / Untersuchungen zur Inaktivierung von HIV-1 in humanen Femurköpfen durch Verwendung eines thermischen Desinfektionssystems (Lobator SD-1).

The use of allogenic bone transplants in surgery has been greatly diminished owing to the risk of transmitting infectious diseases. This risk can be reduced by the use of a thermal disinfection system (Lobator SD-1). This is achieved by increasing the temperature to 80 degrees C, inactivating a number of bacterial and viral agents. In this study the decay of HIV at high temperature in the Lobator SD-1 was researched. In the center of human femoral heads 100 microliters of a highly concentrated suspension of free and cell-bound HIV (10(10)) was exposed to the thermal process at intervals of 5, 10, 20, 30, 40, 50 and 62 min. For the recultivation HUT-78 cells were used through titration of the virus suspension in ten-fold dilutions over ten dilution steps and incubation up to a maximum of 21 days. Evidence of the virus was checked through observing giant cell formations and quantitative determination of p24 antigen using an Elisa test. Linear virus inactivation was found based upon the time the virus was exposed to heat. After a treatment of 40 min in the disinfection system, total virus inactivation was achieved. The normal disinfection process time using Lobator SD-1 is 92 min. A temperature of 80 degrees C is reached after approximately 45 min. The results prove that this system totally inactivates HIV in human femoral heads.

[Monosegmental internal fixator instrumentation and fusion in treatment of fractures of the thoracolumbar spine. Indications, technique and results]. / Die monosegmentale Fixateur interne-Instrumentation und Fusion in der Behandlung von Frakturen der thorakolumbalen Wirbelsäule. Indikation, Technik und Ergebnisse.

Dorsal fusion with the internal fixator has become the standard treatment of instabilities and deformities of the thoracolumbar spine. With our new device, the modular spine fixator (MSF), which has been specially designed for short-distance instrumentations, we have increasingly been treating unstable injuries of the thoracolumbar spine by one-level stabilization. Prerequisite is an accurate evaluation of the indication, including CT and MRI to assess the involvement of the intervertebral disc and the ligamental structures. The operative technique differs in some details from the procedure in more-multi-level instrumentations, especially concerning the application of the pedicle screws. The instrumentation is always combined with posterior allogenic bone grafting. Since the beginning of 1993 we also perform anterior autogenic transpedicular bone grafting. Between January 1991 and July 1995, 57 one-level stabilizations with the MSF were performed. Of the 57 patients operated on 39, 27 men and 12 women, with an average age of 41 years, have had a clinical and radiographic follow-up examination so far, on average, 27 months after the accident. Seventeen patients were completely free of pain and 17 patients (were only) sensitive to weather changes or had minor pain during great physical stress. Five patients had pain even during slight physical stress or at rest. The preoperatively measured Cobb angle was 15.1 degrees on average, after the operation 5.2 degrees, and at the time of the follow-up examination amounted to 8.1 degrees. The patients' range of motion was normal. Only five minor complications have been seen. No implant fatigue failure has been noted in this series. We derive from these results that, for correct indications, one-level stabilization can be performed successfully and should be firmly established in the operative treatment of unstable fractures of the thoracolumbar spine.

[Bone bank management using a thermal disinfection system (Lobator SD-1). A critical analysis]. / Knochenbankmanagement bei Verwendung eines thermischen Desinfectionssystem (Lobator SD-1). Eine kritische Analyse.

In the study presented on 380 allogenic bone donations from living and organ donors, we analyzed the safety of allograft handling bone-band documentation, logistics and costs. For transplant treatment we routinely used a thermal disinfection system (Lobator SD-1). From 380 allograft donors, 400 bone transplants were gained. The rejection rate was 12.2%. After thermal disinfection for 1 h at 80 degrees C, the grafts were cryopreserved at -80 degrees C and released from the bone bank for potential transplantation after 14-16 days. Five of 730 microbiological specimens showed bacterial contamination after thermal graft decontamination. The bacterial species found on the allografts normally have an inactivation temperature under 80 degrees C. Therefore, only secondary contamination can explain the positive bacteriological test results. With reform of the health care system the economical aspects of bone banking have triggered more interest. The cost for one bone transplant released from the bone bank was 424.75 DM: the overall cost for the bone bank in one year was 75,076 DM. Laboratory (58.2%) and material costs (22.5%) were the major factors. Personnel costs and apparatus costs were relatively low (< 20%). With introduction of the thermal disinfection system (Lobator SD-1) into the bone bank, the safety of allogenic bone transplants was greatly improved. Clinical and serological donor screening must be performed according to international bone bank directives. Considering the low rejection rate and the short turnover rate, the economical costs could be reduced. Using an appropriate disinfection system (thermal disinfection at 80 degrees C), laboratory tests covering venereal diseases, malaria and cytomegalia are no longer required. Also, secondary HIV testing of living donors can be omitted without reducing the safety of the transplant.

Non-operative treatment of acute medial collateral ligament lesions of the knee joint.

From 1985 to 1990 102 patients with isolated lesions of the medial collateral ligament of the knee were managed non-operatively with early protected motion and physical therapy. Eighty-six returned to a follow-up examination. The mean follow-up time was 44.2 months. The knees were stable in all but two cases and showed good or excellent results. Ninety-seven percent of the patients returned to their earlier activity level.

[Experimental studies of thermal disinfection and sterilization of allogeneic bone transplants and their effects on biological viability]. / Experimentelle Untersuchungen zur thermischen Desinfektion und Sterilisation allogener Knochentransplantate und deren Auswirkungen auf die biologische Wertigkeit.

Thermal energy (80 degrees) for the disinfection of cancellous allogenic bone grafts was employed, and it proved to be an advantageous, safe and easily accessible method. The effects of this treatment on biological values were examined in terms of biomechanical and biodynamic (graft incorporation) loss of the treated grafts versus the autoclaved and untreated samples. Given the thermolability of the pathogens in question, the thermal approach presented here has the advantage of being readily controllable. The lack of toxic or mutagenic risks through this method and its accessibility represent further advantages. In thermal treatment of bone allografts, it is essential that one knows the thermoconductivity of the bone sample and that one can demonstrate pathogen inactivation through the entire graft volume. All of the parameters in the 80 degrees C group that were measured in this study indicate clear biological superiority over the autoclaved group. A newly developed thermoincubator is introduced for gentler disinfection of allogenic bone grafts and it inactivates common vegetative pathogens as well as HIV. It is still necessary to conduct serological screening for hepatitis antigens in the donor pool, however. Based on these results, we conclude that the clinical use of autoclaved allogenic bone grafts needs to be reviewed and possibly limited.

[Emergency diagnosis of sternum fracture with ultrasound]. / Notfalldiagnostik der Sternumfraktur mit Ultraschall.

Fractures of the sternum often are not discernable on X-rays. The standard lateral X-ray of the sternum may allow the diagnosis. The aim of this study was to find out whether sternal fractures can be visualized by ultrasound. The flat, plane and broad bone provides an ideal rest for a linear scanner; the one used in our study had 5 MHz. We show that sternal fractures can easily be diagnosed by means of ultrasound, and because of an interruption of the cortical reflex, possibly better than on radiographs. We also wanted to show whether sonography, which is in widespread use for the diagnosis of blunt abdominal trauma, can also be used in an emergency situation of blunt thoracic injury (e.g. seat belt injury). In 16 cases of fractures of the sternum already diagnosed by X-ray, an examiner unacquainted with the X-ray results was able to locate and diagnose all fractures by ultrasound within 1 min.