Stress fracture of the patella. Confirmation by triple-phase bone imaging.

An athlete complained of chronic knee pain but had minimal findings on physical examination and initial equivocal radiographs. Subsequent tomograms of the knee suggested a patella stress fracture. Three-phase bone imaging confirmed a stress fracture of the inferior pole of the patella.

Scintigraphic demonstration of pectineus muscle avulsion injury.

An exercise-related avulsion injury of the insertion of the pectineus muscle is described. The abnormality was detected on a 4-hour delayed bone scan. Symptomatic injuries of the adductor muscles are uncommon and are not to be confused scintigraphically with a stress fracture of the proximal femoral shaft.

Ethanol induces the generation of reactive free radicals by neural crest cells in vitro.

Developmental craniofacial anomalies related to the neural crest derived ectomesenchymal cell population are associated with fetal alcohol syndrome (FAS). Information regarding any potential relationship between ethanol, free radicals, and the viability, proliferation, etc., of isolated neural crest cells was sought. The hypersensitivity of neural crest cells to ethanol was observed. This drug severely depressed cell viability while simultaneously inducing the generation of such reactive oxygen intermediates (ROI) as superoxide, hydrogen peroxide, and hydroxyl anions. Addition of the free radical scavenging enzyme superoxide dismutase to the culture medium significantly reversed these effects of ethanol. The cytotoxicity of ethanol was further confirmed by the release of radiolabeled chromium (51Cr) from cells prelabeled prior to ethanol treatment. This effect was also depressed by the addition of superoxide dismutase. Interestingly, an assay for superoxide dismutase activity showed that neural crest cells may be devoid of this enzyme. The latter may help to explain the overt sensitivity of these cells to such a broad spectrum of teratogens, many of which can either dissociate directly into ROI, or cause the radicalization of biological structures and molecules. Plasmalemmal lipids (via lipid peroxidation) and DNA are at an especially high risk from uncontrolled ROI. Changes in neural crest cell surface morphology, i.e., loss of microvilli, formation of xeiotic blebs, as well as the "leakage" of radiolabeled Cr from prelabeled cells, would seem to show that ethanol, as a result of induced free radical formation, alters the physiology and biochemistry of the cell membrane. These findings however, should not exclude other potential sites for ETOH-induced cell injury related to free radicals, especially the nuclei (DNA), mitochondria, organelle membranes, and the cytoskeleton.

Generation of radical oxygen species by neural crest cells treated in vitro with isotretinoin and 4-oxo-isotretinoin.

The effects of isotretinoin (IR) and its primary metabolite (in the human), 4-oxo-isotretinoin (4-OIR or OIR), on isolated chick neural crest cells (NCC's) in culture were studied. NCC's were found to be deficient in both superoxide dismutase (SOD) and catalase, two of the enzymes known to function in the "scavenging" (dismutation) of toxic radical oxygen species (ROS) such as the superoxide anion and hydrogen peroxide. The addition of IR or OIR to the culture medium significantly depressed the viability of the NCC's when compared to untreated cells. OIR was more potent in this regard than IR. In the presence of either IR or OIR, NCC's generated superoxide anions (O2.), hydrogen peroxide (H2O2), and hydroxyl anions (OH.). OIR was again more potent. The cytotoxicity of IR or OIR was demonstrated by the "leakage" of radioactive chromium from prelabeled cells. The latter is suggestive of a primary surface membrane defect, most logically via the induction of lipid peroxides by the retinoids. The latter is accompanied by an increase in membrane permeability and porosity as evidenced by the fact that various fluorescently labeled molecules, including BSA-FITC (MW 69,000), gain entrance into the cytoplasm of the retinoid treated cells. No label was seen in the cytoplasm of similarly treated control cells. When SOD (200 units/ml) or catalase (400 units/ml) was added to the culture media of IR- or OIR-treated NCCs, cell viability was increased and the concentration of the various ROS generated was decreased. Membrane leakiness to chromium and FITC-BSA was also decreased in the presence of these enzymes. Free radicals, when not inactivated (dismutated), are known to be pathobiotic to most cells. Cell membranes are at a particular high risk from ROS which induce structural, physiological, and biochemical alterations in the cell membrane. The latter can have a negative effect on cell permeability, maintenance of normal ionic gradients, membrane enzyme activity, cell-to-cell communication, etc. Such defects can ultimately culminate in hypoplasia, aplasia, and cell necrosis. This study has shown that NCC's may be overtly sensitive to ROS, especially since these undifferentiated cells apparently lack inherent SOD and/or catalase activity. From this study it appears as if both IR and OIR perturb the normal functional state of NCC's by "triggering" the generation of ROS. This may certainly explain the teratogenicity of these drugs as related to the viability of neural crest derived ectomesenchymal cells and normal craniofacial morphogenesis.

Fracture-dislocation of the articular surface of the third metatarsal head.

Fracture of the metatarsal head is uncommon, and reports are rare of isolated osteochondral fracture of the articular surface of the metatarsal head, as occurred in the 18-year-old man reported here. Good results were obtained with closed reduction by manipulation and traction, followed by cast immobilization for 6 weeks.

Spinal arthrodesis for severe spondylolisthesis in children and adolescents. A long-term follow-up study.

The long-term results of spinal arthrodesis were evaluated in fourteen children and adolescents who had severe spondylolisthesis. Twelve patients had an in situ posterior arthrodesis and the other two had, in addition, open reduction. The two patients who had open reduction lost correction when the rods were removed. At long-term follow-up, which averaged 11.9 years, all patients had a solid fusion and their activities were unrestricted. Two patients were dissatisfied with the cosmetic result. No intraoperative or postoperative complications occurred in association with the in situ arthrodeses that were performed alone. Posterior in situ arthrodesis proved to be an effective, reliable, and safe treatment for severe spondylolisthesis.

The pes anserinus transfer. A long-term follow-up.

We evaluated forty-eight patients (fifty knees) with pes anserinus transfer at an average of nine years after operation. There was a high incidence of anteromedial and anterolateral rotatory instability. The incidence (54 per cent) of significant roentgenographic changes at follow-up was also high. Although many patients were improved symptomatically after pes anserinus transfer, only nineteen patients (38 per cent) had no limitation of function.

A chronicle of injuries of an American intercollegiate football team.

Many studies concerning the injuries occurring in high school and intercollegiate football have been reported, including those emphasizing the number and type of injuries, geographic distribution of injuries, and the rate of injury compared to position, conditioning, officiating, equipment, and type of playing surface. This report focuses on the individual player involved in a sports program for four or five years and emphasizes the statistical probability of that individual sustaining an injury during his playing career. Conclusions, drawn from statistics compiled at Memphis State University from 1975 through 1979, involved 265 athletes. These 265 athletes sustained 283 injuries during this period. Of these 283 injuries, 69% were mild, 20% were moderate, and 11% were severe. The knee was most often involved and suffered the most severe injuries. Ankle injuries accounted for the second highest incidence of injury, but these were primarily mild or moderate injuries. The defensive line, especially the defensive ends, received the greatest percentage of injuries. The probability of injury for the individual player was found to be 106.7% for a five-year participant, 99.1% for a four-year participant, and 46.6% for a one-year participant.