The subchondral bone in articular cartilage repair: current problems in the surgical management

As the understanding of interactions between articular cartilage and subchondral bone continues to evolve, increased attention is being directed at treatment options for the entire osteochondral unit, rather than focusing on the articular surface only. It is becoming apparent that without support from an intact subchondral bed, any treatment of the surface chondral lesion is likely to fail. This article reviews issues affecting the entire osteochondral unit, such as subchondral changes after marrow-stimulation techniques and meniscectomy or large osteochondral defects created by prosthetic resurfacing techniques. Also discussed are surgical techniques designed to address these issues, including the use of osteochondral allografts, autologous bone grafting, next generation cell-based implants, as well as strategies after failed subchondral repair and problems specific to the ankle joint. Lastly, since this area remains in constant evolution, the requirements for prospective studies needed to evaluate these emerging technologies will be reviewed

Trochanteric flip osteotomy for cranial extension and muscle protection in acetabular fracture fixation using a Kocher-Langenbeck approach

OBJECTIVE: To describe the advantages and surgical technique of a trochanteric flip osteotomy in combination with a Kocher-Langenbeck approach for the treatment of selected acetabular fractures. DESIGN: Consecutive series, teaching hospital. METHODS: Through mobilization of the vastus lateralis muscle, a slice of the greater trochanter with the attached gluteus medius muscle can be flipped anteriorly. The gluteus minimus muscle can then be easily mobilized, giving free access to the posterosuperior and superior acetabular wall area. Damage to the abductor muscles by vigorous retraction can be avoided, potentially resulting in less ectopic ossification. Ten consecutive cases of acetabular fractures treated with this approach are reported. In eight cases, an anatomic reduction was achieved; in the remaining two cases with severe comminution, the reduction was within one to three millimeters. The trochanteric fragment was fixed with two 3.5-millimeter cortical screws. RESULTS: All osteotomies healed in anatomic position within six to eight weeks postoperatively. Abductor strength was symmetric in eight patients and mildly reduced in two patients. Heterotopic ossification was limited to Brooker classes 1 and 2 without functional impairment at an average follow-up of twenty months. No femoral head necrosis was observed. CONCLUSION: This technique allows better visualization, more accurate reduction, and easier fixation of cranial acetabular fragments. Cranial migration of the greater trochanter after fixation with two screws is unlikely to occur because of the distal pull of the vastus lateralis muscle, balancing the cranial pull of the gluteus medius muscle

MIOR. Grundlagenuntersuchungen zur Erhoehung der Entoelung poroeser Sandsteine durch Einsatz von Melasse und Mikroorganismen Abschlussbericht

The applicability of the molasses-in-situ-process as a tertiary method of improving mineral oil extraction from porous sandstones was studied. A screening programme on the sandstone deposits of the Weser Emsland and Gifhorner Trog showed that, depending on the local stratification, it is possible to isolate halophilic, anaerobic, fermenting microorganismus in particular from oil deposits and sites with extreme ecological conditions. Fifteen bacterial strains having a growth optimum at a temperature of 50 C and a mineralisation of 150 g salt/l were cultured singly and examined with respect to their metabolism. (orig./SR)Es wurde die Anwendbarkeit des Melasse in-situ Verfahrens als tertiaere Methode zur Verbesserung der Erdoelfoerderung aus poroesen Sandsteinen untersucht. Im Screening Programm erfolgte entsprechend der Schichtbedingungen in Sandsteinlagerstaetten des Weser Emslandes und Gifhorner Trogs die Isolation halophiler, anaerober, gaerender Mikroorganismen, ueberwiegend aus Erdoellagerstaetten und von Standorten mit extremen oekologischen Bedingungen. Es konnten 15 Bakterienstaemme mit einem Wachstumsoptimum bei einer Temperatur von 50 C und einem Mineralisationsgrad des Melassenaehrmediums von 150 g Salz/l in Reinkultur gezuechtet und stoffwechselphysiologisch untersucht werden. In Imbibitionsversuchen bei 150 bar und in Flutversuchen unter Schichtbedingungen mit Bentheimer Sandstein und Cornbrash wurden Entwicklung und Produktbildung von Sporohalobacter spec. nachgewiesen. Im Anschluss an ein Wasserfluten wurden durch Melasse in-situ Verfahren 18 bis 21% des residual oil in place zusaetzlich freigesetzt. (orig./SR)SIGLEAvailable from TIB Hannover: F96B644+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Use of muscle cells to mediate gene transfer to the bone defect

Segmental bone defects and nonunions are relatively common problems facing all orthopaedic surgeons. Osteogenic proteins, i.e., BMP-2, can promote bone healing in segmental bone defects. However, a large quantity of the human recombinant protein is needed to enhance the bone healing potential. Cell mediated gene therapy in the bone defect can allow a sustained expression of the osteogenic proteins and further enhance bone healing. Muscle cells can be easily isolated and cultivated, and they are known to be an efficient gene delivery vehicle to muscle and nonmuscle tissues. Furthermore, they are capable of transforming into osteoblasts when stimulated by BMP-2. Thus, the utilization of muscle cells as the gene delivery vehicle to a bone defect would be an important step in establishing a less invasive treatment for non-unions and segmental bone defects. Muscle cells were transduced when the adenoviral-lacZ vector and injected into the bone defect and the muscles surrounding the defect. Expression of the marker gene was visualized 7 days after the injection, both macroscopically and microscopically, using lacZ histochemistry. The lacZ expressing cells in the defect tissue were also stained for desmin, a muscle specific marker, indicating the presence of muscle cells that have fused into myofibers in this nonmuscle bone defect area. With successful myoblast mediated gene delivery into the segmental bone defect, future experiments would focus on delivering viral vectors expressing osteogenic proteins to eventually improve bone healing postinjury