Unstable intertrochanteric/subtrochanteric fractures of the femur.

The unstable intertrochanteric/subtrochanteric fracture, as identified by the modified Müller classification, should be considered a separate entity with its own problems. It can be highly unstable; none of the orthopedic appliances has been designed with this fracture in mind. Compression screws yield better results than Enders rods in these fractures. However, eight patients (16%) in this study who were treated with a compression screw did have a complication. Thus, further studies need to be done to develop other orthopedic appliances for these unstable fractures. Enders rods and compression screws were used to treat 72 unstable intertrochanteric/subtrochanteric fractures. The type of surgical procedure was determined by the surgeon. Anesthesia time and blood loss were significantly lower in the group treated with the Enders nail. Intraoperative and postoperative complications of the Enders group were reported in four (20%) and eight patients (32%), respectively, as compared to zero and eight patients (16%) in the compression screw group. Postoperative time to ambulation, knee pain, and reoperation rate were significantly higher in those treated with the Enders nail. Fracture reduction and ideal device position were acceptable in only 16 patients (64%) and four patients (16%) of the Enders group, respectively, compared with 46 patients (98%) and 40 patients (86%) in the compression screw group.

Is CT useful in the traumatized pediatric elbow?

Recently six radiographic criteria were presented which, when present, indicated that additional imaging of the traumatized adult elbow by means of CT was useful. We applied these 6 criteria to 10 cases of trauma to the pediatric elbow. CT evaluation will not change the therapy dictated by the clinical findings and conventional radiography.

Radioautographic visualization and biochemical identification of O-phosphoserine- and O-phosphothreonine-containing phosphoproteins in mineralizing embryonic chick bone.

We injected NaH2(33)PO4 into normal 14-d-old embryonic chicks and examined the long bones by both radioautography and biochemical analyses from 10 to 240 min after the injection was completed. At 30 min, determination of the radiographic grain density revealed that 33P was concentrated principally in fibroblasts, preosteoblasts, and osteoblasts. With time, there was a progressive increase in the density of silver grains located over both the osteogenic cells and the regions of uncalcified (osteoid) and calcified extracellular organic matrices. Biochemical analyses identified 33P-O-phosphoserine as the major 33P component in glutaraldehyde-treated whole demineralized bone tissue and in EDTA-soluble, nondiffusible proteins extracted from the bones, both at the same time periods that 33P-induced silver grains were visualized by radioautography. 33P-O-phosphothreonine was also identified in experiments using a dosage of 10 mCi per embryo. The results provide the first combined direct biochemical and radioautographic identification that phosphoproteins are synthesized in bone and are located morphologically at the sites of mineralization. The data provide further evidence that phosphoproteins play a critical role in the biological calcification of vertebrate tissues.

Histological evaluation of cutaneous wound healing in presence of nitrous oxide in rats.

Three-centimetre linear incisions were made in 90 young male Lew/f Mai rats by scalpel through skin to the investing fascia of the left flank. The skin was undermined sharply for a distance of 0.5 cm along both sides of the entire length of the incision. The wound site was closed per primam with Michel clips and left uncovered. Following emergence from anesthesia, rats were randomly allocated to one of three groups of 30 rats each: one group breathed air only and acted as control; the second was exposed to 20% N2O for 24 hours daily until sacrificed (continuous group); the third was exposed to 20% N2O for 8 hours daily until sacrificed (intermittent group). Ten rats from each of the three groups were sacrificed after 3, 7, or 10 days postincision. After sacrifice, sections from the wound stained with hematoxylin and eosin or reticulin were examined microscopically. No histological evidence of an effect on wound healing of skin occurred in rats exposed to 20% N2O.

The development of the elastic cartilage of the mouse pinna.

The development of the elastic cartilage in the mouse pinna was studied with the electron microscope. For descriptive purposes, the developmental process was divided into five stages. These begin with the onset of cartilage matrix production by chondroblasts. The second stage is the major mitotic stage although the cells now resemble chondrocytes and cartilage matrix production evidently continues. This is followed by a period during which cartilage matrix production appears to be the major activity of the chondrocytes. In Stage IV, the cells continue to produce cartilage matrix but at the same time they also produce lipid which comes to occupy most of the cell as a large lipid droplet. In the adult, Stage V, matrix production appears to be at an end and each cell contains a lipid droplet which is so large that the cells bear some resemblance to white fat cells and might be designated as lipochondrocytes. The adult cartilage matrix contains elastic plates in a three-dimensional honeycomb pattern. Between the elastic plates and the cells, the matrix contains elements similar to those seen in hyaline cartilage but it does not contain matrix vesicles such as those which have been associated with the calcification of cartilage. Two types of filaments differing in appearance, size, and location are seen within the chondrocytes. They have been designated cytofilaments and cortical filaments. Cytofilaments are dispersed throughout the cell and also contact the substance of the lipid droplet; cortical filaments (sub-plasmalemmal microfilaments) are located directly under the plasma membrane. They are thought to be involved in movement of the plasma membrane as a concomitant to extracellular fibrogenesis.