Muskuloskelettale Gewebebanken

[A clinical radiological score for femoral head grafts : Establishment of the Tabea FK score to ensure the quality of human femoral head grafts]

INTRODUCTION

Transplantation of cancellous tissue from human femoral heads (FK) is an established method in the reconstruction of bony defects in orthopedic and trauma surgery. Standardized rating systems with respect to the morphological quality of this tissue are not available.

MATERIALS AND METHODS

In 91/105 patients who had been a regular, clinically-indicated surgery (arthroplasty of the hip joint) the respective femoral head (FK) was taken under standardized conditions. Using a checklist defined clinical and radiological criteria of FK are judged in terms of their quality (cysts, necrosis, calcification, deformities, osteoporosis) and divided by the Tabea FK score into three classes (best/middle/poor quality). This was followed by a blinded repeated scoring, now as macroscopic assessment of three sawed layers from the same femoral head. The femoral heads are examined by peripheral quantitative computed tomography (pQCT) and a standardized histological examination of the bony tissue. We evaluated the accordance of the Tabea FK score with complementary assessments by calculation of sensitivity and specificity.

RESULTS

Femoral heads from 91/105 patients (ages: 68.4 ± 9.9 , n = 60 women, n = 31 men) were explanted and included in the study. The correlation between the primary radiologic clinical score (Tabea FK score) and the macroscopic second review of the sawn FK with respect to middle/best and poor/middle quality was classified as good (sensitivity 77% and 81%, respectively; specificity 76% and 84%, respectively). The correlation of histology and macroscopic second review was worse and in relation to discrimination of middle/best and poor/middle quality had a sensitivity of 85% and 54%, respectively, and a specificity of 66% and 97%, respectively. The pQCT showed a sensitivity of 82% only in discrimination of middle/best, while sensitivity in discrimination of poor/middle and poor/middle + best, respectively, was <10%.

DISCUSSION

The corresponding correlation between the primary and the second clinical score was evaluated as good. This emphasizes the long-standing skills of operationally active orthopedic surgeons to classify the quality of cancellous bone correctly already on the basis of X‑ray images and intraoperative findings. In this respect, the introduction of the Tabea FK score as a quality assurance tool in the routines of bone banks can be recommended.

Irradiation sterilization used for allogenetic tendon: a literature review of current concept

Tendon injury is a very common type of sports trauma, and its incidence has increased over the past decades. Surgical reconstruction with tendon allograft has been increasingly used to restore the motor function and stability of the injured site. However, the risk of disease transmission caused by allogeneic tendon transplantation has been a major problem for tissue bank researchers and clinicians. In order to eliminate the risk of disease transmission, a process of terminal sterilization is necessary. Ionizing irradiation, including gamma irradiation and electron beam irradiation is the most commonly used method for the terminal sterilization, which has been widely proved to be able to effectively inactivate the contained pathogens. Nevertheless, some accompanying damage to the mechanical and histological properties of collagen fibers in tendons will be caused. Therefore, more and more studies have begun to pay attention to the protective effect of radiation protection agents, including the radical scavengers and cross-linking agents, in the irradiation sterilization of allogeneic tendons.

Regional experiences of tissue donation and forensic medicine in hamburg - results of a 5-year period

OBJECTIVE

We present the operational organization and daily workflow of our Hamburg model and the results of the years 2007-2011 concerning donation of corneas, musculoskeletal and, since 2010, cardiovascular tissues.

METHODS

Each of the about 3,600 deceased every year undergoes an evaluation process by two coordinators on duty, the tissue coordinator and the family coordinator. All donation connected issues are carried out within the standardized protocols of a quality management system and documented in a special data base. Two catamnestic surveys evaluated the satisfaction of donor families retrospectively. The inclusion rate for cornea donation was 23% and for musculoskeletal donation 10%, with a decrease after the 75 years age restriction of musculoskeletal donors in 2011 defined by the contracting tissue bank German Institute for Cell and Tissue Replacement gGmbH (DIZG), Berlin.

RESULTS

Since 2007 1,268 corneas were explanted altogether, reflecting an increasing explantation rate from 156 (University Medical Center Hamburg-Eppendorf (UMC: 9) in 2007 up to 304 (UMC: 52) in 2011. Overall 173 musculoskeletal donors (5 years) and 11 cardiovascular donors (2 years) spent tissues. The consent rate was much higher. The evaluation of the families reflected a positive feedback for the guiding of the donation process.

CONCLUSION

Forensic institutes can act as an interface between donors and recipients without neglecting forensic investigations. They are uniquely positioned to recognize potential donors. In addition, the contact with a physician of the forensic institute may help families during the mourning phase.

Effect of electron beam irradiation on biomechanical properties of patellar tendon allografts in anterior cruciate ligament reconstruction

BACKGROUND

Sterilization of anterior cruciate ligament (ACL) allografts is an important prerequisite to prevent disease transmission. However, mechanical tissue properties are compromised by most current sterilization procedures, so that uncompromised sterilization of allografts is difficult to achieve. Hypothesis/

PURPOSE

The aim of this study was to evaluate the effect of the novel electron beam sterilization procedure on the biomechanical properties of human patellar tendon allografts at various irradiation dosages. Electron beam sterilization may be an appropriate alternative to gamma sterilization.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-two human 10-mm wide bone-patellar tendon-bone grafts were randomized into 4 groups of sterilization with 15, 25, or 34 kGy of electron beam irradiation, respectively. The grafts' biomechanical properties were evaluated at time zero. Unsterilized grafts functioned as controls. Biomechanical properties were analyzed during cyclic and load-to-failure testing.

RESULTS

Strain and cyclic elongation response showed no significant differences between the groups. Electron beam irradiation had no significant effect on stiffness and failure load with the exception of 34 kGy, which resulted in a significant decrease in failure load (1300.6 +/- 229.2 N) compared with unsterilized grafts (1630.5 +/- 331.1 N).

CONCLUSION

This study showed that electron beam might be an appropriate alternative in sterilization of patellar tendon allografts with minimal effect on mechanical properties of tendon grafts in vitro. Future studies will have to evaluate the effect of the process on the biological properties of allografts in vitro and in vivo.

CLINICAL RELEVANCE

Terminal sterilization of patellar tendon allografts with electron beam irradiation can ensure higher safety of transplanted grafts and hence improve patient safety and acceptance.

[Acetabular defect reconstruction in revision surgery of the hip. Autologous, homologous or metal?]

The treatment of periprosthetic bone defects of the acetabulum is a therapeutic challenge in hip revision surgery. The aims are the biological reconstruction of osseous acetabular defects and the restoration of a load-bearing acetabular bone stock as well as restoring the physiological joint biomechanics and achieving primary and load-stable fixation of the revision graft in the vital pelvic bone. The biological reconstruction of the acetabular bone stock should include what is referred to as "down-grading" of the acetabular defect situation in case a repeat revision procedure becomes necessary.Nowadays, a large variety of grafts and reconstruction procedures are available for the reconstruction of acetabular defects. The choice of suitable materials (osseous or metallic) for the restoration of a load-bearing acetabular bone stock is currently the subject of controversial discussion.This article reviews the various options for the reconstruction of acetabular bone defects taking into consideration the current findings in the scientific literature.

The Impact of the German Tissue Act on the Manufacturing of Autologous and Allogeneic Stem Cell Preparations

SUMMARY: Cellular therapeutic agents considerably contribute to the optimal treatment of patients with hematological malignancies such as leukemia or nonhematological disorders. Over the last 50 years especially the transplantation of autologous and allogeneic stem cells from different sources after high-dose or myeloablative chemotherapy became a well-established standard therapy that cures or alleviates the symptoms in more than 50,000 patients/year worldwide. In the near future, the current progress in fundamental research on stem cells and immunobiology will allow for the clinical implementation of novel advanced cellular therapies, including gene therapeutic options. The European and German legislation have realized the need of international regulations for improved standardization and harmonization of stem cell transplants, associated cell-therapeutic agents as well as various tissue-engineered preparations in the emerging field of regenerative medicine. The Tissue Directive 2004/23/EC, issued and ratified by the European Parliament in March 2004, and its national transition into the German Tissue Act which came into force in July 2007 define the quality and safety standards for the donation, procurement, testing, processing, preservation, storage, and distribution of human tissues and cells. These standards are of high relevance to ensure the efficient prevention of the transmission of viral and nonviral infectious pathogens and to achieve the same safeguards as in the population's blood supply. This review discusses the pros and cons of the new legislation and argues for keeping the administrative and regulative demands in reasonable limits and for offering innovative approaches of cellular therapies to the European citizens.