A biomechanical study of four different meniscal repair systems, comparing pull-out strengths and gapping under cyclic loading.

Most studies comparing the biomechanical properties of different meniscal repair systems have simply investigated load to failure. Meniscal tissue is highly anisotropic, and far weaker under tension in the radial direction. Radially oriented loading to failure may not therefore be the most physiologically relevant in vitro test for repair of circumferential tears, and determining gapping across repair sites under cyclical loading at lower loads may be of greater importance. Using bovine menisci, vertical circumferential incisions were repaired using a simple vertical 2-0 PDS suture, Meniscal Arrow, Meniscal Fastener or T-Fix. Repairs were tested by simple loading to failure in a materials testing machine, and by cyclic loading between 5 and 10 N for 25 cycles. Initial gapping across the repairs was measured using a digital micrometer, and the increase in gapping under cyclic loading measured using a Differential Voltage Reluctance Transducer. The mean loads to failure for each of the repair groups were: sutures 72.7 N, Arrows 34.2 N, Fasteners 40.8 N and T-Fix 49.1 N. The load to failure was significantly greater with sutures than with Arrows or Fasteners. The mean gapping across the repairs for each of the repair groups after 25 loading cycles were: sutures 3.29 mm, Arrows 2.18 mm, Fasteners 3.99 mm and T-Fix 3.47 mm. The mean gapping was significantly less with Arrows than with Sutures, Fasteners or T-Fix. These results confirm that meniscal repair by suturing gives the highest load to failure, but show that Arrows give superior hold under lower loads, with the least gapping across repairs under cyclic loading of the four methods tested.

Case report. Post-traumatic tibial recurvatum: resolution with growth.

The outcome of proximal tibial fractures in children is often complicated by the development of malalignment. Progressive valgus deformity is frequently seen, but is known to correct spontaneously in a high proportion of cases; however, recurvatum of the tibia usually requires surgical intervention. We present a child with a proximal tibial metaphyseal fracture who developed increasing tibial recurvatum which corrected spontaneously.

Neonatal thymic haemorrhage.

Thymic haemorrhage in a neonate is an exceedingly rare condition. A case is presented of a neonate presenting at birth with cyanosis, respiratory distress and an anterior mediastinal mass. The radiological findings are demonstrated. After surgical excision and histopathological examination the lesion was found to be spontaneous haemorrhage into normal thymic tissue. Spontaneous thymic haemorrhage should be considered in any neonate developing acute respiratory distress with widening of the mediastinum and pleural effusion on chest radiography. Ultrasound may be used to support the diagnosis.

5. Update on lasers in dermatology.

A range of lasers with acceptably low rates of side effects is now available. Improved laser therapy has been made possible by combining wavelengths that are selectively absorbed by the target and pulses short enough to prevent heat transfer to surrounding tissue. Carbon dioxide (CO2) lasers are useful for treating disorders of skin surface texture and topography (wrinkles, scars, sun damage, benign skin appendages and rhinophyma). Vascular lasers, such as the flashlamp-pumped dye laser, are particularly effective for treating port-wine stains, haemangiomas, telangiectasia, rosacea and spider naevi. Q-switched lasers, which allow ultrashort high intensity pulses, are effective for treating most tattoos and some benign pigmented lesions.

Unilateral erythromelanosis follicularis faciei et colli in a young girl.

Erythromelanosis follicularis faciei et colli is uncommon. Fewer than 20 cases have been reported. Except for one case in a woman and one case of unilateral distribution, all other reported cases have been bilateral in young male patients. We report the first case of unilateral distribution in a white girl.

Long-term pulmonary sequelae after Legionella pneumophila infection in the hamster.

It has been reported that infections with Legionella pneumophila can lead to chronic inflammatory and fibrotic reactions in the human lung. To better characterize the nature of the residual abnormalities caused by this bacterium, we inoculated Syrian hamsters intratracheally with 10(8) serotype 1 L. pneumophila organisms and assessed histologic, functional, and biochemical changes at intervals up to 180 days. Acutely, L. pneumophila caused an intense alveolar macrophage (AM) and polymorphonuclear leukocyte (PMN) response within the lower air spaces, air-filled lungs were noncompliant, and there was an associated 25 to 50% increase in the lung content of collagen and elastin after 10 days. An inflammatory response, consisting principally of AM and centered around the terminal bronchioles, was still prominent in some infected lungs after 90 and 180 days, and the severity of the inflammation was correlated with a persistent restrictive defect in the elastic behavior of the lung. However, by histologic examination, fibrosis was not prominent, and the more representative abnormality was one of mild, diffuse air-space enlargement. Frank emphysematous changes were present focally in some lungs. In addition, an irregularly distributed lymphocytic infiltrate and goblet cell metaplasia were present in the larger bronchi of infected animals. We conclude that a single infection with L. pneumophila is capable of causing long-term inflammatory reactions in the lung, with morphologic features of both fibrosis and emphysema.

Chemotactic and phagocytic responses of human alveolar macrophages to activated complement components.

Human alveolar macrophages (AMs) migrated toward and aggregated to C5a but not toward C5a-deficient serum. Human AMs from cigarette smokers migrated significantly farther than did AMs from nonsmokers. Human AMs phagocytized Escherichia coli opsonized with activated C3. Immunoglobulin G was not required for phagocytosis. Human AMs demonstrate chemotaxis and aggregation to C5a. Further, human AMs can phagocytize bacteria coated with activated C3.