Pulmonary toxicity following exposure to a tile coating product containing alkylsiloxanes. A clinical and toxicological evaluation.

CONTEXT: Coating products are widely used for making surfaces water and dirt repellent. However, on several occasions the use of these products has been associated with lung toxicity. OBJECTIVE: In the present study, we evaluated the toxic effects of an aerosolized tile-coating product. METHODS: Thirty-nine persons, who reported respiratory and systemic symptoms following exposure to the tile-coating product, were clinically examined. The product was analysed chemically and furthermore, the exposure scenario was reconstructed using a climate chamber and the toxicological properties of the product were studied using in vivo and by in vitro surfactometry. RESULTS: The symptoms developed within few hours and included coughing, tachypnoea, chest pain, general malaise and fever. The physical examination revealed perihilar lung infiltrates on chest radiograph and reduced blood oxygen saturation. The acute symptoms resolved gradually within 1-3 days and no delayed symptoms were observed. By means of mass spectrometry and X-ray spectroscopy, it was shown that the product contained non-fluorinated alkylsiloxanes. The exposure conditions in the supermarket were reconstructed under controlled conditions in a climate chamber and particle and gas exposure levels were monitored over time allowing estimation of human exposure levels. Mice exposed to the product developed symptoms of acute pulmonary toxicity in a concentration-and time-dependent manner. The symptoms of acute pulmonary toxicity likely resulted from inhibition of the pulmonary surfactant function as demonstrated by in vitro surfactometry. Among these patients only a partial association between the level of exposure and the degree of respiratory symptoms was observed, which could be because of a high inter-individual difference in sensitivity and time-dependent changes in the chemical composition of the aerosol. CONCLUSION: Workers need to cautiously apply surface coating products because the contents can be highly toxic through inhalation, and the aerosols can disperse to locations remote from the worksite and affect bystanders.

Dietary conjugated linoleic acid changes belly and bacon quality from pigs fed varied lipid sources.

The objective of this experiment was to determine the effects of dietary lipid source with or without the addition of CLA on bacon composition and quality. Forty-eight barrows at a beginning BW of 55 kg +/- 2.2 were fed 1 of 6 diets for 56 d. These diets consisted of: 1) normal corn (NC), 2) NC + 1.25% CLA-60 oil (NC + CLA), 3) high-oil corn (HOC), 4) HOC + 1.25% CLA-60 oil (HOC-CLA), 5) NC + choice white grease (CWG; NC + CWG), and 6) NC + CWG + 1.25% CLA-60 oil (NC + CWG + CLA). The CLA-60 contains 60% CLA isomers in the oil, and therefore, 1.25% oil was needed to achieve 0.75% CLA in the diet. Soy oil replaced CLA in control diets. Choice white grease and high-oil corn were selected as fat sources for this study because of their utility in energy density for growing-finishing pigs, especially in hot weather. Pigs were slaughtered at an average BW of 113 kg +/- 4.1, and carcasses were fabricated at 24 h postmortem. Statistical analysis was performed using the mixed model procedure of SAS, and the main effects tested were dietary lipid source, CLA, and 2-way interaction. The addition of CLA to each basal diet improved (P < 0.05) belly firmness measured either lean side down or fat side down from the belly bar firmness test [4.39 cm vs. 7.01 cm (lean down) and 5.75 cm vs. 10.54 cm (fat down)] for 0 and 0.75% dietary CLA, respectively. The compression test used on bacon slabs showed that bacon from CLA-supplemented pigs was approximately 20% firmer than that from controls. Pigs fed the HOC diets had softer bellies compared (P < 0.05) with pigs fed the NC diet as measured by the belly bar test [6.94 cm vs. 9.26 cm (fat down)], respectively. Conjugated linoleic acid did not, however, improve bacon sliceability. No differences were observed for moisture, protein, or lipid percentages between any treatments. Overall, there was a CLA effect (P < 0.04) for lipid oxidation, in which the addition of CLA decreased bacon oxidation (0.1498 CLA vs. 0.1638 no CLA). Dietary CLA increased the percentage of SFA in tissues from pigs supplemented with CLA. Dietary inclusion of CLA increased the concentration of all measured isomers of CLA in bacon. Sensory scores of bacon showed no differences for any of the sensory attributes measured between any of the treatments. Our results indicate that inclusion of dietary CLA will improve belly firmness, extend the shelf life stability of bacon, and increase the degree of fat saturation.

Do indoor chemicals promote development of airway allergy?

UNLABELLED: Allergic asthma has increased worldwide in the industrialized countries. This review evaluates whether the major groups of indoor chemical exposures possess allergy-promoting (adjuvant) effects; formaldehyde was excluded, because of the size of the literature. Volatile organic compounds (VOCs) are used as an example of gases and vapors. The precipitation of asthmatic symptoms by VOC exposures is probably because of VOC levels considerably above typical indoor levels, or VOCs may be a surrogate for exposure to allergens, combustion products or dampness. Indoor particles possessed adjuvant effects in animal studies and allergy-promoting effects in humans. Quaternary ammonium compounds may possess adjuvant effects in animal studies and promoted sensitization in humans in occupational settings. The use of cleaning agents, anionic and non-ionic surfactants are not considered to possess an important adjuvant effect in the general population. Regarding phthalate exposures, results from animal and epidemiological studies were found to be discordant. There is little evidence that the indoor chemicals evaluated possess important adjuvant effects. If buildings are kept clean, dry and free of combustion products, the important question may be would it be profitable to look for lifestyle factors and non-chemical indoor exposures in order to abate airway allergy? PRACTICAL IMPLICATIONS: Indoor chemicals (pollutants) have been accused to promote development of airway allergy by adjuvant effects. In this review, we evaluated the scientific literature and found little support for the supposition that indoor chemicals possess important adjuvant effects. This rises the question: would it be profitable for abatement of airway allergy to look for non-chemical indoor exposures, including lifestyle factors, and exposures to allergens, microorganisms, including vira, and their interactions?

Effect of short-term lairage on the prevalence of Salmonella enterica in cull sows.

This study was designed to compare Salmonella enterica prevalence in sows held in a holding pen at the abattoir for approximately 2 h (hold sows) with sows slaughtered immediately after transport to the abattoir (no-hold sows). Cull sows (n = 160) were sampled from four sampling periods over 8 weeks (February to March 2002) at the abattoir. Sows originated from an integrated swine farm and were sent to a live-hog market and then to the slaughter facility. Before testing, sows entered the abattoir pen and four 100-cm2 four-ply gauze squares were placed randomly on the pen floor for S. enterica culture. Sows were alternatively assigned to the hold or no-hold group. Samples collected from sows during slaughter were ileocecal lymph node, cecal contents, transverse colon contents, subiliac lymph node, sponge swabs of the left and right carcass section (300 cm2), and chopped meat. Overall, S. enterica was isolated from 44% (35 of 80) of the no-hold sows, which was significantly less (P < 0.05) than 59% (47 of 80) of the held sows. Also, no-hold sows had a lower cecal content prevalence (39%, 31 of 80) compared with that (55%, 44 of 80) of held sows (P < 0.05). S. enterica serovars isolated from no-hold sows were Brandenburg (n = 16), Derby (n = 12), Hadar (n = 8), Infantis (n = 6), Johannesburg (n = 3), 6,7:z10-monophasic (n = 3), and Typhimurium (n = 1). S. enterica serovars isolated from held sows (n = 61 isolates) were Derby (n = 19), 6,7: z10-monophasic (n = 15), Brandenburg (n = 10), Infantis (n = 6), Hadar (n = 5), Johannesburg (n = 4), and Tennessee (n = 2). Serovars recovered from the pen were Reading (n = 6), Derby (n = 4), Uganda (n = 2), and Manhattan (n = 2). Results of this study suggest that holding pens contribute to increased S. enterica carriage in cull sows. Abattoir holding pens might be an important control point for S. enterica in the ground pork production chain.

Monophthalates promote IL-6 and IL-8 production in the human epithelial cell line A549.

The dramatically increasing prevalence of allergic respiratory diseases may in part be due to the presence of certain immunotoxic xenobiotics in the environment. Recent studies have suggested that some plasticizers belonging to the phthalate family, and metabolites thereof, play a role in the development of allergic respiratory diseases. This is probably due to an adjuvant effect, which in some cases may be combined with an inflammatory process. The scope of the present study was to investigate the inflammatory potential of monophthalates, which are degradation products of phthalate plasticizers. The human epithelial cell line A549 was exposed to 15.6-2000 microg/ml, in two-fold dilutions, to either mono-n-butyl phthalate, monobenzyl phthalate, mono-n-octyl phthalate, mono-2-ethylhexyl phthalate, mono-iso-nonyl phthalate or mono-iso-decyl phthalate. Concentrations of the proinflammatory cytokines IL-6 and IL-8 were measured in the cell culture supernatant by ELISA. The study showed that some, but not all, monophthalates could induce a concentration-dependent increase in cytokine production, whereas, at higher concentrations, all phthalates suppressed cytokine production. Both the stimulatory and the suppressive properties were highly dependent on the length of the alkyl side chain of the monophthalate - a structure-activity relationship that is supported by recent observations in mice.

Impact of commercial preharvest transportation and holding on the prevalence of Salmonella enterica in cull sows.

The objective of this study was to examine the prevalence of Salmonella enterica in cull sows at various stages from the farm to the abattoir. Cull sows (n=181) were sampled over 10 weeks. Fecal samples (10 g each) were collected on the farm ca. 24 h before loading and at the live-hog market ca. 3 h before loading. Samples (ileocecal lymph nodes, cecal contents, feces from the transverse colon, ventral thoracic lymph nodes, subiliac lymph nodes, sponge swabs of the left and right carcass sections, and chopped meat) were collected at the abattoir. The percentages of positive fecal samples on the farm and at the live-hog market were 3% (5 of 181 samples) and 2% (3 of 181 samples), respectively. After transport from the live-hog market (10 h) and holding at the abattoir (6 h), 41% (74 of 180) of cull sows yielded S. enterica in one or more sampled tissues. The isolation rate for total cecal contents (33%; 60 of 180 samples) was significantly (P<0.05) higher than those for ileocecal lymph nodes (7%; 12 of 181 samples), feces (11%; 20 of 181 samples), and ventral thoracic and subiliac lymph nodes (2%; 4 of 181 samples). Before a 2% lactic acid carcass wash (lasting 8 to 9 s), 14% (25 of 180) of carcasses were positive, compared with 7% (12 of 179) after the wash (P<0.05). Two S. enterica serotypes, Derby and Infantis, were found on the farm and at the live-hog market. At the abattoir, 12 serotypes that had not previously been found on the farm or at the live-hog market were recovered. The results of this study demonstrate that transport and holding practices may contribute to an increase in S. enterica infection prior to slaughter to levels much higher than those found on the farm.

Investigation of the adjuvant and immuno-suppressive effects of benzyl butyl phthalate, phthalic acid and benzyl alcohol in a murine injection model.

In a recent study, di-(2-ethylhexyl) phthalate (DEHP) and its metabolite, mono-2-ethylhexyl phthalate, were shown to possess adjuvant effect [Toxicology 169 (2001) 37; Toxicology Letters 125 (2001) 11]. The present study investigates the adjuvant effect of another important commercial phthalate plasticizer, benzyl butyl phthalate (BBP) as well as its degradation products, phthalic acid and benzyl alcohol (BA) in a murine model. The model antigen, ovalbumin (OA), was injected either alone (OA control group), together with one of the test substances (test group) or together with aluminium hydroxide, which served as the positive adjuvant control. The mice were boosted either once or twice with OA before blood was collected and assayed for the content of OA-specific IgE, IgG1 and IgG2a antibodies by ELISA methods. Adjuvant effect was defined as a statistically significant increased antibody level in the test groups compared with the OA control group. Conversely, if the antibody production in a test group was significantly lower than the OA control group, it was deemed to be immunosuppression. This study demonstrated that BBP, in contrast to DEHP, did not possess adjuvant effect. Furthermore, immunosuppression was apparent in the case of BA. The study also demonstrated that if the injections give rise to formation of wounds, it may cause false positive results.

Adjuvant and immuno-suppressive effect of six monophthalates in a subcutaneous injection model with BALB/c mice.

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America. This increase in disease prevalence may be associated with environmental pollutants. The present study investigated the adjuvant and immuno-suppressive effect of a series of monophthalates which are considered to be important metabolites of commonly used phthalate plasticizers. The effects were studied in a screening model. Ovalbumin (OA), used as the model antigen, was injected subcutaneously in the neck region of BALB/cJ mice with or without one of the test substances, mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBnP), mono-n-octyl phthalate (MnOP), mono-2-ethylhexyl phthalate (MEHP), mono-iso-nonyl phthalate (MiNP) or mono-iso-decyl phthalate (MiDP). The levels of OA-specific IgE, IgG1 and IgG2a in sera were measured by ELISA. Immuno-suppressive effect, defined as a statistically significant reduction in IgE or IgG1 antibody production, was observed with MEHP (1000 microg/ml, IgE and IgG1), MnOP (1000 microg/ml, IgE and IgG1), MiNP (1000 microg/ml, IgE and 10 microg/ml, IgG1) and MiDP (100 microg/ml, IgE and IgG1). Adjuvant effect, defined as a statistically significant increase in IgE or IgG1 antibody level, occurred with MEHP (10 microg/ml, IgE), MnOP (100 microg/ml, and 10 microg/ml, IgG1) and MiNP (100 microg/ml, IgE). No statistically significant immune modulating effect was seen with MBnP and MnBP.

Formation of strong airway irritants in mixtures of isoprene/ozone and isoprene/ozone/nitrogen dioxide.

We evaluated the airway irritation of isoprene, isoprene/ozone, and isoprene/ozone/nitrogen dioxide mixtures using a mouse bioassay, from which we calculated sensory irritation, bronchial constriction, and pulmonary irritation. We observed significant sensory irritation (approximately 50% reduction of mean respiratory rate) by dynamically exposing the mice, over 30 min, to mixtures of isoprene and O3 or isoprene, O3, and NO2. The starting concentrations were approximately 4 ppm O3 and 500 ppm isoprene (+ approximately 4 ppm NO2. The reaction mixtures after approximately 30 sec contained < 0.2 ppm O3. Addition of the effects of the residual reactants and the identified stable irritant products (formaldehyde, formic acid, acetic acid, methacrolein, and methylvinyl ketone) could explain only partially the observed sensory irritation. This suggests that one or more strong airway irritants were formed. It is thus possible that oxidation reactions of common unsaturated compounds may be relevant for indoor air quality.

Conjugated linoleic acid improves feed efficiency, decreases subcutaneous fat, and improves certain aspects of meat quality in stress-genotype pigs.

Conjugated linoleic acid (CLA) was supplemented to crossbred growing-finishing barrows (n = 60) at 0.75% of the total diet. Pigs were randomly assigned to the CLA or control diets based on stress genotype (negative, carrier, or positive). Gain:feed was higher for CLA diet animals (350 g/kg feed) than for control diet animals (330 g/kg feed) independent of genotype (P < 0.05). No differences were observed for ADG for the diets (P = 0.71) or genotype classes (P = 0.40). Postmortem pH was lower (P < 0.01) by 3 h for CLA-supplemented pigs, with no differences in ultimate pH. No differences (P = 0.16) were observed for ultimate pH between the three genotypes. Conjugated linoleic acid-supplemented pigs exhibited less 10th rib fat depth (2.34 cm vs 2.84 cm) and last rib fat depth (2.46 cm vs 2.72 cm) than control pigs (P < 0.05). Loin muscle area (LMA) was not affected (P = 0.18) by CLA supplementation, but LMA was different (P < 0.02) for genotype; positive genotype carcasses had the largest LMA (45.02 cm2) and negative carcasses had the smallest LMA (36.44 cm2). Carrier carcasses were intermediate for LMA (40.76 cm2). Subjective scores for color were not affected (P = 0.98) by CLA but color was different (P < 0.01), with scores of 1.50, 2.40, and 3.1 for positive, carrier, and negative genotypes, respectively. Subjective marbling scores were increased (P < 0.03) in all genotypes with CLA supplementation. Subjective firmness scores were higher (P < 0.06) for CLA-supplemented pigs and were highly correlated (0.89) to marbling scores. The L* values were higher (P < 0.01) for stress-positive pigs at 24 h postmortem. Also, L* values were higher (P < 0.01) for CLA-fed pigs over 7 d of shelf storage. Sensory characteristics were not different with CLA supplementation for tenderness (P = 0.24), juiciness (P = 0.35), or flavor intensity (P = 0.14). This study showed that LMA was increased with stress-carrier and stress-positive genotypes, but lean color was negatively affected with the presence of the stress gene. Conjugated linoleic acid supplementation improves feed efficiency, decreases backfat, and improves pork quality attributes of marbling and firmness of the longissimus muscle. Furthermore, there is seemingly no interaction between the stress-genotype status of pigs and the subsequent effect of CLA on their growth and performance.

Total body electrical conductivity (TOBEC) measurement of compositional differences in hams, loins, and bellies from conjugated linoleic acid (CLA)-fed stress-genotype pigs.

This study was designed to observe the effects of conjugated linoleic acid (CLA) supplementation on lean content of pork carcass primal cuts (hams, loins, and bellies) and to determine the ability of total body electrical conductivity (TOBEC) to predict lean content. A total of 64 crossbred growing-finishing barrows were placed on a control (soybean oil) or CLA (0.75%) diet at an average weight of 40 kg. Pigs were penned in pairs according to diet and stress genotype (negative, carrier, and positive) and slaughtered at 115 kg. Stress genotype was included because of known variations in lean content. Hams (IMPS 401A; n = 64), loins (IMPS 410; n = 24), and bellies (IMPS 408; n = 63) were fabricated from carcasses at 24 h postmortem and scanned for electromagnetic (EM) absorption by a MQ-25 EM scanner. Each wholesale cut was scanned in triplicate at 2.5 MHz to yield a peak mean average (PMA) value then separated into lean, fat, bone, and skin components. Bellies were skinned prior to scanning then subjected to a belly bar firmness test before dissection. Supplementation with CLA had no effect (P > 0.05) on lean ham composition. Regression analysis was used for lean weight prediction using primal weight and PMA value as predictors. Lean content prediction of hams by TOBEC resulted in an R2 of 0.80. Loins from CLA-supplemented pigs exhibited increased lean weight (P < 0.05) and PMA values (P < 0.05) compared to controls. Lean prediction of loins by TOBEC resulted in an R2 of 0.66. Bellies from CLA-supplemented pigs had a higher percentage of moisture (P < 0.03) and protein (P < 0.01) and decreased percentage of lipid (P < 0.01). The R2 values from the regression analysis predicting protein, moisture, protein + moisture, and fat-free soft tissue composition of the skinless bellies were 0.67, 0.68, 0.71, and 0.78, respectively.

Effects of R-(+)- and S-(-)-limonene on the respiratory tract in mice.

The effects of airborne R-(+)- and S-(-)- limonene were studied in conscious BALB/c mice by continuous monitoring respiratory rate (f), tidal volume (VT) and mid-expiratory flow rate (VD) during an exposure period of 30 min. Both enantiomers decreasedf from a trigeminal reflex, i.e., due to sensory irritation. The exposure concentration decreasing f by 50% (RD50) in the first 10 min of the exposure period was estimated to be 1,076 ppm for R-(+)-limonene and 1,467 ppm for S-(-)-limonene. Results for sensory irritation of R-(+)-limonene in BALB/c mice and humans are in close agreement. The reported sensory irritation threshold is above 80 ppm in humans while the no-observed-effect level was estimated to be 100 ppm in mice. The enantiomers were devoid of pulmonary irritation or general anesthetic effects with R-(+)-limonene < or =1,599 ppm and S-(-)-limonene < or =2,421 ppm. R-(+)-limonene did not influence VT below 629 ppm. S-(-)-limonene increased VT above 1,900 ppm. Both enantiomers induced a mild bronchoconstrictive effect above 1,000 ppm.

Effects of methacrolein on the respiratory tract in mice.

The acute respiratory effects of airborne exposure to methacrolein were studied in a recent refinement of the standard test method with mice (ASTM, 1984. American Society for Testing and Materials, Philadelphia). Irritation of the upper respiratory tract caused a concentration-dependent decrease in the respiratory rate of 2-26 ppm methacrolein. In this range, only a minor airflow limitation occurred in the lower respiratory tract, suggesting that the main effect of methacrolein is sensory irritation. During exposure, the sensory irritation response maintained the same level, i.e. no desensitisation occurred. The concentration 10.4 ppm methacrolein reduced the respiratory rate by 50% (RD50). The extrapolated threshold for the respiratory depressing effect, RD0, was 1.3 ppm. The sensory irritation effect of methacrolein was compared with results from closely related compounds in order to elucidate the mechanism of the interaction between methacrolein and the sensory irritant receptor.

Acute airway effects of formaldehyde and ozone in BALB/c mice.

1. Concentration and time-effect relationships of formaldehyde and ozone on the airways were investigated in BALB/c mice. The effects were obtained by continuous monitoring of the respiratory rate, tidal volume, expiratory flow rate, time of inspiration, time of expiration, and respiratory patterns. 2. With concentrations up to 4 p.p.m., formaldehyde showed mainly sensory irritation effects of the upper airways that decrease the respiratory rate from a trigeminal reflex. The no-effect level (NOEL) was about 0.3 p.p.m. This value is close to the human NOEL, which is about 0.08 p.p.m. 3. Ozone caused rapid, shallow breathing in BALB/c mice. Later on, the respiratory rate decreased due to another vagal response that indicated an incipient lung oedema. The NOEL in mice was about 1 p.p.m. during 30 min of ozone exposure. No major effect occurs in resting humans at about 0.4 p.p.m. 4. Thus, the upper airway irritant, formaldehyde, and the deep lung irritant, ozone, showed the same types of respiratory effects in humans and in BALB/c mice. Also, the sensitivity was nearly identical. Continuous monitoring of respiratory effects in BALB/c mice, therefore, may be a valuable method for the study of effects of other environmental pollutants, which, however, should be confirmed in further studies.

Respiratory effects in mice exposed to airborne emissions from Stachybotrys chartarum and implications for risk assessment.

Stachybotrys chartarum, a mycotoxin producing mould found in some damp buildings, was grown in aluminum dishes in closed exposure chambers. The loading factor, 5.12 m2/m3, corresponded to 2.8 times the loading in a normal room with all surfaces covered by mould. Sensory irritation, bronchoconstriction and pulmonary irritation effects were investigated using a sensitive mouse bioassay in which the airway reactions were measured plethysmographically. Little effect was seen from the vapours in agreement with the predicted effects of the low concentrations of volatile organic compounds measured. Even under the influence of an airflow about four times that measured in normal buildings, the concentration of liberated spores and other particles was very low, corresponding to the biological effects observed, and probably reflecting the high water content of the substrate. These results demonstrate that many factors are important for the transport of biologically active mould metabolites from building material to occupants and that no direct relationship may exist between immediate biological effects and surface area covered with mould. Therefore, risk assessments should be based on estimated effects of emitted vapours, effects of liberated particles, e.g. sensitization potentials of the mould spores and effects of the generated metabolites (mycotoxins).

Revision after osteotomy for gonarthrosis. A 10-19-year follow-up of 314 cases.

During a 10-year period, 314 tibial osteotomies were performed for medial gonarthrosis. At follow-up after 10-19 years, 62 knees had been revised by arthroplasty (52 cases) or reosteotomy (10 cases). The revision rate was 54/170 in undercorrected knees and 8/144 in knees with normalization or overcorrection of the hip-knee-ankle angle. Our results confirm that tibial osteotomy for gonarthrosis requires proper indications and precise surgery. Perhaps, given another 10 years, our osteotomies will have outlived contemporary arthroplasties.

Temperature elevation during knee arthroplasty.

The temperature in the tibia and in the saw blade were recorded during 30 knee arthroplasty operations. In the saw blade the median maximum temperature was 68 degrees C (45-100 degrees C). The corresponding bone temperatures at two levels approximately 2 and 3 mm below the cutting surface were 47 degrees C and 42 degrees C, respectively. Irrigation of the saw area with physiologic saline solution had only a minimal effect. During the cement-curing process, the temperature was 37 degrees C (31-50 degrees C) at the cement-bone interface. We conclude that the cutting procedure generates heat above the critical temperature for bone necrosis that may harm prosthetic fixation, notably for bone ingrowth.

The significance of hemarthrosis of the knee in children.

Diagnostic arthroscopy was performed in 40 consecutive patients under 16 years of age with hemarthrosis of the knee. The age of the patients ranged from 10 to 15 years, median 13.7 years. Eighteen patients had ruptures of the anterior cruciate ligament; seven ruptures were partial. Only two cases of fractures of the tibial spine were encountered. Seven patients had midsubstance tears of the anterior cruciate ligament. Eleven patients had patellar dislocations. Six patients had minimal capsular disruptions as the cause of hemarthrosis. Three patients had osteochondritis dissecans of the knee and two patients had isolated ruptures of the medial collateral ligament. Twenty-eight of the patients underwent some form of operative repair. The clinical diagnosis was confirmed at arthroscopy in 17 of the 40 cases. The appearance of hemarthrosis of the knee usually signifies a serious knee injury and should be treated with the same importance as in adults, and as a rule arthroscopy should be carried out.

Arthroscopy of the knee in children.

Diagnostic arthroscopy was performed in 174 consecutive patients under the age of 18 years. Eight arthroscopies were bilateral. The clinical diagnosis was confirmed in only three of 17 knees in children under aged 14 years and in 44 per cent of the knees in older children. The most commonly disproved diagnoses were torn meniscus and chondromalacia patella. Arthroscopy seldom changed the diagnosis in cases of osteochondritis dissecans. In 38 per cent of the knees, arthroscopy revealed no surgical treatable abnormality, and unnecessary arthrotomy was avoided. Arthroscopy in acute hemarthrosis revealed that ligamentous tears are rather common in children; in nine of 25 knees a partial or complete tear of the anterior cruciate ligament was demonstrated at arthroscopy. The clinical diagnosis was confirmed in eight knees in cases of hemarthrosis. There was no significant difference between the hemarthrosis group and the remaining group as regards a disproved clinical diagnosis. We conclude that arthrotomy should always be preceded by diagnostic arthroscopy in children and adolescents if the clinical diagnosis leaves any doubt.