Incidence and outcomes of anterior cruciate ligament reconstruction among U.S. Army aviators

BACKGROUND: The incidence, injury history and aeromedical disposition of anterior cruciate ligament (ACL) reconstruction among Army aviators is unknown. METHODS: The U.S. Army Aviation Epidemiology Data Register was queried for the study period of calendar years 1988-95. Factors considered included age, gender, type and mechanism of injury, prior history of ACL reconstruction, and final aeromedical disposition. The population was divided into two groups: Group I aviators had no history of ACL injury before entering aviation service, while Group II aviators had ACL reconstructions prior to entering aviation service. The data set was analyzed to determine the incidence of ACL reconstruction, to characterize the type and mechanism of injury and to determine the risk of aeromedical termination from service. RESULTS: The ACL reconstruction rate (ACL reconstructions/1000 aviators per year) was 0.52 overall, 0.50 for males and 1.39 for females. Sports accounted for 76% of the injuries requiring ACL reconstruction. The ACL reconstruction rate in Group I was 0.050%, while that of Group II was 63.3%. Among Group I aviators requiring ACL reconstruction, 94.3% returned to aviation service, 2.3% were aeromedically terminated and 3.4% were lost to follow-up. Among Group II aviators requiring revision ACL reconstruction, 60% returned to aviation service and 40% were aeromedically terminated. CONCLUSION: Female aviators and Group II aviators had the greatest risk of requiring ACL surgery. Group II aviators had a greater likelihood of undergoing a revision ACL reconstruction and subsequent aeromedical termination compared with an initial ACL reconstruction for Group I aviators.     

A framework for incorporating cost-effectiveness in evidence-based clinical practice guidelines.

In England, recent health care reforms emphasise the role of clinical guidelines in promoting effective and efficient health care. Introducing economic data into guidelines raises some methodological issues: specifically, the provision of valid and generalisable cost estimates, the weight placed upon cost 'evidence', and the presentation of cost-effectiveness information in a manner accessible to clinicians. A series of primary care guidelines, explicitly including consideration of health economic information, have recently been published, intended to help clinicians to aggregate the attributes of treatment choices to derive treatment recommendations consistent with both the clinical decision-making process and social objectives. Clinicians involved in developing guidelines responded well to the process and consistently managed to agree treatment recommendations, often after considerable debate about the evidence for treatment. In none of the guideline areas, all of which addressed common diseases, was there adequate information to estimate a cost per quality-adjusted-life-year, and it is unclear how helpful this approach would have been had it been possible. The implications of this method are discussed, guidance offered for economists new to guideline development and future areas of work identified.     

Oxidative stress occurs in perfused rat liver at low oxygen tension by mechanisms involving peroxynitrite

Ethanol increases free radical formation; however, it was recently demonstrated that it also causes extensive hypoxia in rat liver in vivo. To address this issue, it was hypothesized that peroxynitrite formed in normoxic periportal regions of the liver lobule has its reactivity enhanced in hypoxic pericentral regions where the pH is lower. Via this pathway, peroxynitrite could lead to free radical formation in the absence of oxygen. Livers from fed rats were perfused at low flow rates for 75 min. Under these conditions, periportal regions were well oxygenated but pericentral areas became hypoxic. Low-flow perfusion caused a significant 6-fold increase in nitrotyrosine accumulation in pericentral regions. During the last 20 min of perfusion, the spin-trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone was infused and adducts were collected for electron-spin resonance analysis. A six-line radical adduct signal was detected in perfusate. Direct infusion of peroxynitrite produced a radical adduct with identical coupling constants, and a similar pattern of nitrotyrosine accumulation was observed. Retrograde perfusion at low rates resulted in accumulation of nitrotyrosine in periportal regions. Although the magnitude of the radical in perfusate was increased by ethanol, it was not derived directly from it. Both nitrotyrosine accumulation and radical formation were reduced by inhibition of nitric oxide synthase with N-nitro-L-arginine methyl ester, but not with the inactive D-isomer. Radical formation was decreased nearly completely by superoxide dismutase and N-nitro-L-arginine methyl ester, consistent with the hypothesis that the final prooxidant is a derivative from both NO. and superoxide (i.e., peroxynitrite). These results support the hypothesis that oxidative stress occurs in hypoxic regions of the liver lobule by mechanisms involving peroxynitrite.     

Pay Status as a Predictor of Outcome in Surgical Treatment of Obesity

Background: Higher complication rates and lower success in surgery for severe obesity have been reported for patients with government pay status. We examined the effect of pay status upon outcome in surgical treatment of obesity. Methods: This was an observational study from an aggregate data set of individual patient information. Government pay status (G) was defined as full or partial medical care payment through Medicare, Medicaid, or Veterans Administration. Payment entirely by private insurance was defined as private (P). Operations were classified as either simple (S, gastric restriction) or complex (C, gastric restriction with small bowel bypass). Two measures of outcome, perioperative complication rate and weight loss success (≤50% excess weight), were examined to determine pay status effect. Results: More G than P patients were treated with simple procedures (79% vs 51%, p < 0.05). Perioperative complication rates were more common for G than P patients (14.4% vs 9.1%, p < 0.05). One-year weight loss success was higher for P than G, regardless of operation type. Conclusion: Pay status should be included in characterization of patient groups and in the analysis of results when effectiveness of surgical treatment for severe obesity is reported.     

Acceptance of Surgery for Obesity by Academic Surgeons in North America

BACKGROUND: Have surgeons in North America accepted operations for the treatment of severe obesity? This question was posed by organizers of the Ninth International Symposium on Obesity Surgery that met in Stockholm in September, 1995. Study design: In order to obtain opinions which might help to answer the question posed, a 1-page questionnaire was sent to 151 chairmen of academic departments of surgery in North America in December 1994 asking about the acceptance and use of surgical operations for the treatment of severe obesity. RESULTS: Answers, received from 112 or 74%, indicated that operative treatment should be used (74%), was effective (77%) and safe (71 %). However, only 65% of departments provided such operations. Operative treatment for obesity was available outside the department in 53%. The operations most frequently used were Roux-en-Y gastric bypass (RGB) and vertical banded gastroplasty (VBG). A single operation was offered by 44 departments and a choice of two or more operations in 30 departments. RGB and VBG were equally in use. Gastric banding was used as an alternative to VBG in six departments. Other operations were in use in six departments either alone (three) or as alternatives to RGB and VBG (three). CONCLUSIONS: It appears that surgical treatment of obesity is accepted and available in the majority of academic departments of surgery.