Bone augmentation by replica-based bone formation.

Objective: The sources of iliac crest bone grafts are limited. Alternatives are evaluated due to the progress in biomaterial sciences. Synthetical hydroxyapatite (HA), ß-tricalcium phosphate (ß-TCP) or biphasic compounds, or even a mélange of HA and ß-TCP will replace bovine ceramics.

Long-term results of reconstructing the joints' articular surface in the knee and ankle with the surgical diamond instrumentation (SDI).

Purpose: The surgical diamond instrumentation (SDI), a precise wet-grinding technology, promised contact healing of press-fit inserted bone and even hyaline cartilage, lacks medium- and long-term results. This retrospective study was conducted to identify risk factors associated with the failure of the technique and the subjective patient outcome.

Methods: All patients treated for cartilage defects of the knee or ankle joint using the SDI technology between 2000 and 2012 with a follow-up > 1 year were included.

Autologous resurfacing.

Background: There is a discrepancy between the interest in joint-reconstructions and the current knowledge about the healing-processes involved. Major reconstructions are performed with osteosynthesized allografts and fresh allografts for cartilage.

Objectives: The main question to be answered is: what do we know about metaphyseal and epiphyseal cancellous bone healing, contact healing of the subchondral bone and its influence on cartilage healing? Can we achieve healing of all four compartments in contact?

Purpose: The purpose is to systematically investigate through animal testing the healing processes of metaphyseal and epiphyseal bone, including the subchondral bone and the healing of cartilage of press-fit-inserted grafts, considering nondemineralized high-resolution histology.

[Primary cancellous bone formation around micro-chambered beads].

Objectives: The question has been raised whether benign bone defects in patients can be treated with bone forming osteoconductive ceramics achieving primarily a cancellous bone scaffold, which is under load from the beginning.

Material And Methods: Ten reconstructions were performed in 9patients (6women and 3male), with a mean age of 49 (25-65)years, suffering a high variety of epi- and metaphyseal defects, four tibial fractures, two calcaneal fractures, one pathological phalangeal fracture, one chondroma of the distal femur and two open-wedge osteotomies were filled with micro-chambered ceramic beads of 4 and 6mm in diameter. The mean follow up was 22 (7- 8)months.

The bone-to-cement interface improvement by Ca-phosphate ceramics.

Background: Polymethylmethacrylate used in surgery is one of the first biomaterials. Conventional histology dissolves the resin; one of the reasons that only few complete histology is published. OBJECTIVES AND PURPOSE: The question is, whether a complete histology changes the understanding, influences the application and opens approaches for improvements.

Osseointegration of hydroxyapatite and remodeling-resorption of tricalciumphosphate ceramics.

Background: Cancellous bone defects surrounded by still intact bone structures never heal. Ceramics offer a solution providing osteoconductive scaffolds.

Purpose: The purpose of the study is to evaluate whether structured β-TCP and HA implants can reconstruct cancellous bone defects, which role micro- and macro-porosity, stiffness and surface area play; finally the indication for both materials based on its resorbability.

Primary cancellous bone formation with BMP and micro-chambered beads: experimental study on sheep.

Problem: The physiological reconstruction of cancellous bone defects in surgery of the locomotor system is an unsatisfactorily solved problem.

Aims: The aims of this study are to examine whether micro-chambered ß-tricalcium-phosphate (ß-TCP) beads provide a certain capillary force suctioning in blood and bone marrow thus forming a stable "negative"-replica of the bone marrow spaces. If so, a new approach for osteoconduction would yield primarily a scaffold of lamellar cancellous bone under load without a long-lasting remodeling process.

Value and limits of μ-CT for nondemineralized bone tissue processing.

An experimental approach was performed on 20 giant rabbits to establish the possibilities and limitations of μ-CT for routine processing of nondemineralized bone tissue. Hydroxyapatite (HA) or β-tricalciumphosphate (β-TCP) bead implants or a melange of both, microchambered and solid, were implanted into a standardized and precise defect in the patellar groove. The bone-healing phase was chosen for the histology considering 1 or 2 days, and 2, 3, and 6 weeks.

How bone forms in large cancellous defects: critical analysis based on experimental work and literature.

The behaviour of physiological biomaterials, β-tricalciumphosphate and hydroxyapatite, is analysed based on current literature and our own experimental work. The properties of graft substitutes based on ceramic materials are clearly defined according to their scientific efficiency. The strength of the materials and their biodegradability are still not fully evaluated.

Dose-dependent osteoinductive effects of bFGF in rabbits.

Growth factors lead to the induction of tissue regeneration in bone healing when coated on biomaterials. Basic fibroblast growth factor (bFGF) combines osteoinduction and neoangiogenesis. This study evaluated bFGF-coated hydroxylapatite implants in two experimental groups with 10 or 100 microg (n = 5 per group) compared with uncoated control implants in the rabbit patellar groove model.

Methotrexate-loaded polymethylmethacrylate bone cement for local bone metastasis therapy: pilot animal study in the rabbit patellar groove.

Local chemotherapy is an option in bone metastasis treatment. On the other hand, evaluation of side effects on bone is a difficult issue in drug development and biomaterials research. Most animal models to date are inappropriate or not feasible.

Histological examination of drill sites in bovine rib bone after grinding in vitro with eight different devices.

The way in which bone is processed may affect the quality of the specimen and how much information may be gleaned on histological examination. We investigated eight widely used rasps and drills and compared the results. All large chip cutters damaged the bed and marrow of the bone.

Strain adaptive bone remodelling in total joint replacement.

Histomorphologic analyses of artificial joint components implanted into bone need special technology for processing and for documentation; published histological work systematically done therefore is rare. The histopathology, three-dimensionally analyzed in a complete sequence of sections is, however, the only precise answer in terms of biocompatibility and bone response. A complete analysis allows a type-related predictable prognosis of an implantation that is at least comparable to a finite element analysis with respect to load transfer to host bone.

[A new experimental model for repetitive osseous blood supply measurement].

The aim of this study was to establish a novel model permitting repetitive analysis of osseous perfusion over a period of 33 days using the fluorescent microsphere technique. After implantation of two port systems into the right and left carotid artery in New Zealand rabbits (n = 3), fluorescent microspheres were injected into the left ventricle, while blood samples for reference probes were taken from the descending aorta. Using seven different fluorescently labeled microspheres, injections were repeatedly performed starting 3 days after implantation (t = 0) at days 1, 3, 5, 12, 19, 26, and 33.

[Anatomic basis of the cemented femur shaft. A comparative study of straight and anatomic design].

Aim: The purpose of this study was to compare cemented anatomic stems with cemented straight stems regarding cement mantle and stem orientation in the medullary canal.

Methods: In a cadaver study, 10 anatomic SP II stems and 10 MEM straight stems were implanted in paired human femora using a standardised modern cementing technique. In one group the femoral canal was prepared using conventional broaches, in the other group diamond hollow-cutters were used.

The John Charnley Award. Prophylaxis of fat and bone marrow embolism in cemented total hip arthroplasty.

The efficiency of a new cementing technique developed to prevent the risk of intraoperative pulmonary embolism was assessed. Seventy patients with coxarthrosis entered into a prospective, randomized clinical trial. In the control group of 35 cases the total hip replacement was cemented conventionally.

[The significance of blood vessels on both sides of the growth plate].

A new 3-D presentation of the whole vasculature of the epiphyseal growth plate clearly allows for a distinction between arterial and venous sections of the blood circulation. Histological investigations using these processing methods could neither prove the connection between epiphyseal and metaphyseal vessels through the growth plate in newborns nor the concept of an arterial epiphyseal blood supply of the growth plate presented by Trueta. It is rather a question of an arterial metaphyseal perfusion and an epiphyseal venous drainage system.

Biological effects of shock waves: in vivo effect of high energy pulses on rabbit bone.

Extracorporeal shock waves have recently been introduced to treat pseudarthrosis and aseptic bone necrosis. Only little information exists up to now about the morphological effects of shock waves on normal bone. To study both their acute effect on bone and their long-term effect on its remodelling, 1500 shock waves generated with a Dornier XL1 experimental electrohydraulic lithotripter were applied at 27.

Modern cementing techniques. An experimental study of vacuum insertion of bone cement.

The results of these experiments show that an increase in the intramedullary pressure (IMP) can lead to embolization of bone marrow contents via the venous drainage system along the linea aspera. A vacuum applied distally to the medullary canal is very effective for filling the diaphyseal tube with cement. The cancellous bone honeycombs of the proximal metaphysis, however, can only be filled if the bone sponge is tunneled at the level of the femoral calcar; a proximal vacuum then yields filling of the cancellous bone framework with bone cement.