The treatment of chondral and osteochondral defects of the knee with autologous matrix-induced chondrogenesis (AMIC): method description and recent developments

Purpose: Articular resurfacing by treatment of chondral defects may include chondral abrasion, autologous chondrocyte Implantation (ACI), matrix-induced chondrocyte transplantation (MACT) or osteochondral autologous transplantation (OATS). This technical note describes the method of autologous matrix-induced chondrogenesis (AMIC), a one-step procedure combining subchondral microfracture with the fixation of a collagen I/III membrane with fibrin glue or sutures. Methods: This is a technical note on the AMIC procedure and its further development. Results and conclusion: This method is applied primarily in chondral or osteochondral lesions of the knee. Indications and contraindications are provided; the technique is described. The further development of AMIC is described with an increased focus on the subchondral zone and the complex of cartilage and bone, the osteochondral unit, which receives increased attention in cartilage research. Level of evidence: I

We do not have evidence based methods for the treatment of cartilage defects in the knee

Purpose: The aim of this study was to perform a systematic review of studies concerning current treatment of chondral defects of the knee. Methods: The relevance for evidence based data and for successful surgical treatment of cartilage defects was evaluated. From 56,098 evaluated studies, 133 studies could be further pursued. These supplied data concerning microfracturing, the osteochondral autograft transplantation system (OATS), the autologous chondrocyte implantation (ACI) and the matrix induced chondrocyte implantation (MACI). The modified Coleman Methodical Score (CMS) and the Level of Evidence (LOE) were applied to evaluate the quality. Results: In these studies, a total of 6,920 patients were reviewed with a median of 32 patients per study and a mean follow-up of 24months. The mean CMS was 58 of 100 points. No study reached 100 points in the CMS. Three studies reached a level above 90. Ten studies were Level I, five studies reached Level II. Seven studies reached Level III, 111 studies Level IV. MRI scans to verify the clinical data were used by only 72 studies. The means in the modified CMS were for the different procedures as follows: ACI 58 points, MACI 57 points, microfracturing 68 points and OATS 50 points. 24 studies applied the Lysholm Score (LS) for clinical evaluation of cartilage surgery. All operative procedures yielded comparable improvements of the LS (n.s.) meaning that no operative procedure proved superior. Conclusion: As the majority of studies evaluated by this review is insufficient for EBM purposes more coherent studies with LOE of I or II are needed. Co-relating the systems of CMS and LOE and validating the applied scores seems desirabl

Adjustment of the Mechanical Properties of Silicone for Applications in the Middle Ear

In case of loss of the auditory ossicular chain, the application of a middle ear prosthesis is necessary. For this prosthesis, a silicone pad shall be developed to minimize pressure peaks and for the prevention of forcing of the tympanic membrane. It is important to adjust the mechanical properties for best hearing quality. Therefore different siloxanes and additives like nanoporous silica nanoparticles are used. The latter also can act as drug carriers. The visco-elastic properties of the silicone can be changed significantly by slight variations of the composition.DFG/SFB/59

Birds (Aves), Serrania Sadiri, Parque Nacional Madidi, Depto. La Paz, Bolivia

We surveyed the Serrania Sadiri for birds at elevations between 500-950m for a combined total of 15 days in three different months. The area surveyed was along the Tumupasa/San Jose de Uchupiamones trail at the edge of Parque Nacional Madidi in Depto. La Paz, Bolivia. We report observations of 231 species of birds detected by sight and sound, including many outlying ridge specialists. We report and present photographs of a new species for Depto. La Paz (Caprimulgis nigrescens), the second Bolivian localities for Porphyrolaema prophyrolae ereicapillus, and Basileuterus chrysogaster, and five new species records for Parque Nacional Madidi

In vivo testing of a bioabsorbable magnesium alloy serving as total ossicular replacement prostheses

Magnesium alloys have been investigated in different fields of medicine and represent a promising biomaterial for implants due to characteristics like bioabsorbability and osteoinduction. The objective of this study was to evaluate the usability of magnesium as implant material in middle ear surgery. Magnesium implants were placed into the right middle ear of eighteen New Zealand White rabbits. Nine animals were euthanized after four weeks and nine animals after three month. The petrous bones were removed and embedded in epoxy resin. The specimens were then polished, stained and evaluated with the aid of a light microscope. The histological examination revealed a good biocompatibility. After four weeks, a beginning corrosion of the implant's surface and low amount of trabecular bone formation in the area of the stapes base plate was observed. A considerable degradation of implants and obvious bone formation was found three month after implantation. The magnesium alloy used in the present study partly corroded too fast, so that a complete bone reconstruction could not be established in time. The increased osteoinduction on the stapes base plate resulted in a tight bone-implant bonding. Thus, a promising application of magnesium could be a coating of biomaterials in order to improve the bony integration of implants. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

Mesoporous silica films as a novel biomaterial: Applications in the middle ear

In this tutorial review we present the process of the development of functional implants using mesoporous silica. The different steps from chemical synthesis and physicochemical characterization followed by in vitro testing in cell culture assays to clinically relevant in vivo animal studies are examined. Since the end of the 1990s, mesoporous silicas have been considered as biomaterials. Numerous investigations have demonstrated their non-toxic and biocompatible properties. These qualities in combination with the unique properties of high surface area and pore volume, uniform and tunable pore sizes and chemical modifiability are the reasons for the great scientific interest in this field. Here we show that besides bulk materials or mesoporous silica nanoparticles, mesoporous silica films are highly promising as coatings on medical prostheses or implants. We report on the development of functionalized mesoporous silica materials specifically for middle ear applications. Middle ear prostheses are used to restore the sound transmission through this air-filled cavity when the small bones of the middle air (the ossicular chain) have been destroyed by disease or by accidents. In addition to optimal restoration of sound transmission, this technique bears several challenges, e.g. an ongoing bacterial infection or the displacement of the prosthesis due to insufficient fixation. To improve the healing process, a mesoporous silica coating was established on ceramic middle ear prostheses, which then served as a base for further functionalizations. For example, the bone growth factor BMP2 was locally attached to the coating in order to improve the fixation of the prosthesis by forming a bony connection to the remainder of the ear bones. Further, an implant-based local drug delivery system for the antibiotic ciprofloxacin was developed with the aim of fighting bacterial infections. Further possibilities using mesoporous silica nanoparticles as part of a composite on an implant are briefly discussed. © The Royal Society of Chemistry 2013

Nanoporous Silica Films as Novel Biomaterial: Applications in the Middle Ear

We have introduced nanoporous silica as a novel biomaterial. Nanoporous silica is non-toxic and biocompatible. It provides a high surface area and pore volume, uniform and tunable pore sizes and the possibility for chemical modification. We have shown that nanoporous silica coatings on middle ear prostheses provide a suitable basis for installing various functionalizations which can improve the healing after the insertion of the implant.DF