The influence of postoperative coronal alignment on revision surgery in total knee arthroplasty

This study examines the association between postoperative coronal tibiofemoral alignment and revision surgery in knee arthroplasty. We retrospectively reviewed the case notes and post-operative long-leg radiographs of 197 Kinemax knee arthroplasty with mean follow-up of 9 years (SD 2.2). They were divided into three groups: neutral, valgus and varus. Revision or decision to revise was used as a hard endpoint. There was no statistical difference among the three groups (p=0.78). We conclude that aseptic failure of a total knee is multifactorial. Coronal tibio-femoral alignment may not be as important a cause of failure as has been previously thought.     

Urgent carotid endarterectomy is safe in patients with few comorbid medical conditions

Recent reports from single institutions have confirmed the efficacy of carotid endarterectomy (CEA) performed in the urgent or emergent setting, although with higher perioperative mortality and morbidity. We determined the results of urgently performed CEA in academic and community hospitals and whether patient or hospital factors affected outcome. The records of patients undergoing CEA in all nonfederal hospitals in the state of Connecticut between 1992 and 2002 were reviewed, and symptomatic patients who presented in an urgent or emergent fashion were compared to patients treated electively. Multivariable logistic regression was used to determine the effect of patient risk factors on perioperative mortality, stroke, and cardiac complications. Patients undergoing urgent CEA (n = 764, 6.3%) had higher perioperative mortality (2.0% vs. 0.3%, p < 0.0001) and stroke (2.9% vs. 1.1%, p < 0.0001) but not cardiac complications (3.0% vs. 2.2%, p = 0.14) compared to patients undergoing elective CEA (n = 11,312). Patients undergoing urgent CEA and with high rates of associated comorbidity had a higher risk of perioperative mortality (7.8% vs. 0.4, p = 0.001), stroke (10.9% vs. 0.8%, p = 0.0002), and cardiac complications (14.1% vs. 0.8%, p < 0.0001) compared to patients presenting urgently but with little comorbidity. Perioperative mortality was associated with performance of the procedure in hospitals with low bed capacity (odds ratio [OR] = 4.6, p = 0.01). Perioperative stroke was associated with renal insufficiency (OR = 5.3, p = 0.04). Perioperative cardiac complications were associated with diabetes (OR = 2.6, p = 0.03) and performance in hospitals with low bed capacity (OR = 5.0, p < 0.01). Urgent admission was associated with age >/=80 (OR = 1.2, p = 0.04), renal disease (OR = 1.8, p = 0.05), and cardiac disease (OR = 1.3, p < 0.01). Urgently performed CEA has higher perioperative mortality and stroke compared with electively performed cases. However, the subset of patients with low rates of associated comorbid medical conditions but urgently needing CEA is associated with low rates of perioperative complications. Patients with severe associated comorbid medical conditions who present urgently for CEA may form a high-risk group of patients to be considered for referral to large treatment centers or possibly alternative therapy.     

Association of methylenetetrahydrofolate reductase genetic polymorphisms with atlantoaxial dislocation

OBJECT: Genetic mechanisms of atlantoaxial dislocation (AAD) have not previously been elucidated. The authors studied association of polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, which encodes enzymes of the folate pathway (implicated in causation of neural tube defects [NTDs]), in patients with AAD. METHODS: Molecular analysis of MTHFR polymorphisms (677C-->T, cytosine to thymine and, 1298A-->C, adenine to cytosine, substitutions) was carried out using polymerase chain reaction and restriction enzyme digestion in 75 consecutive patients with AAD and in their reducible (nine patients, 12%) and irreducible (66 patients, 88%) subgroups. Controls were 60 age- and sex-matched patients of the same ethnicity. Comparisons of genotype and allele frequencies were performed using a chi-square test (with significance at p < 0.05). RESULTS: The CT genotype frequency of MTHFR 677C-->T polymorphism was significantly increased in the full group of patients with AAD (odds ratio [OR] 3.00, 95% confidence interval [CI] 1.28-7.14, p = 0.005) as well as in the irreducible subgroup (OR 2.81, 95% CI 1.17-6.86, p = 0.01). The frequency of T alleles was also higher in the AAD group (25.3%) than in controls (15%). The comparison of the combined frequency of CT and TT genotypes with the frequency of the CC genotype again showed significant association in AAD (OR 2.63, 95% CI 1.98-5.90, p = 0.009) and the irreducible (OR 2.5, 95% CI 1.1-5.74, p = 0.016) subgroup. There was, however, no significant association of MTHFR 1298A-->C polymorphism with AAD. CONCLUSIONS: Both MTHFR 677C-->T polymorphism and higher T allele frequency have significant associations with AAD, especially the irreducible variety. Perhaps adequate supplementation of periconceptional folic acid to circumvent effects of this missense mutation (as is done for prevention of NTDs) would reduce the incidence of AAD.     

Infectious scleritis: Clinical spectrum and management outcomes in India

In this retrospective case series, we studied the predisposing factors, causative organisms, clinical spectrum, and outcomes of 12 cases of culture-proven infectious scleritis. Nine of 12 patients had a history of preceding trauma (surgical or accidental). Past surgical history included small-incision cataract surgery (4), pterygium surgery (1), and trabeculectomy (1). Six patients had multifocal scleral abscesses due to Pseudomonas, Klebsiella, or Nocardia. Only 2 patients retained useful vision (>6/18). A poor visual acuity at presentation usually resulted in a worse visual outcome (P = 0.005). Four eyes developed phthisis. The addition of surgical intervention did not result in a significantly better visual outcome than medical management alone (P = 0.209), but resulted in a higher globe preservation rate (P = 0.045). Therefore, we concluded that infection must be ruled out in cases of scleritis with preceding history of trauma, and aggressive surgical intervention improves the anatomical outcome but does not change the visual outcome.     

Atrophy of the rotator cuff muscles and site of cuff tears

We determined the relationship between the site of rotator cuff tears and atrophy of the cuff muscles. 28 shoulders (28 patients) had rotator cuff tears: 19 isolated tears of the supraspinatus tendon (isolatedtear group) and 9 combined tears of the supraspinatus and infraspinatus tendons (combined-tear group). The cross-sectional area of the subscapularis, supraspinatus, the infraspinatus and teres minor muscles in the coronal oblique MR images were measured before and after surgery. Although we found no difference in tear size, the cross-sectional areas of the muscles were smaller in the combined-tear group than in the isolated-tear group. We conclude that atrophy of the supraspinatus and infraspinatus muscles also depends on the site of the tear.     

[I]Epibatidine-labelled nicotinic receptors in the extended striatum and cerebral cortex: lack of association with serotonergic afferents

In rat extended striatum, most nicotinic cholinoceptors are likely to be presynaptic. A previous report suggested that DA and 5-HT afferents each account for at least 30% of nicotinic binding sites in the striatum. To explore this question further, rats received unilateral infusions of the neurotoxins 5,7-dihydroxytryptamine, 6-hydroxydopamine or vehicle into the medial forebrain bundle, and were sacrificed 3 weeks later. Denervation was quantified by [¹²⁵I]RTI-55 autoradiography, using separate assay conditions that revealed DA and 5-HT transporters (i.e. DAT and SERT). Nicotinic cholinoceptors were quantified by [¹²⁵I]epibatidine autoradiography. Infusion of 6-hydroxydopamine depleted DAT but not SERT labelling in all striatal areas (i.e. caudate-putamen, nucleus accumbens core and shell, olfactory tubercle). The serotonergic neurotoxin 5,7-dihydroxytryptamine depleted SERT and, to a lesser extent, DAT labelling. Both neurotoxins reduced [¹²⁵I]epibatidine binding in striatal areas. Multiple linear regression analysis showed that these reductions in [¹²⁵I]epibatidine binding were entirely associated with loss of DAT rather than SERT. The DAT-associated proportion of total [¹²⁵I]epibatidine binding was 36±2% (caudate-putamen), 28±3% (accumbens core), 27±4% (accumbens shell) and 44±5% (olfactory tubercle). Cortical [¹²⁵I]epibatidine binding was unaltered by 5,7-dihydroxytryptamine lesions that reduced SERT labelling by 46 to 73%. In all brain areas, even small (3.4 to 8.8%) SERT-associated reductions in [¹²⁵I]epibatidine binding would have been detected as statistically significant. In conclusion, we report the failure to detect nAChRs on 5-HT terminals in extended striatum or cerebral cortex, using a sensitive [¹²⁵I]epibatidine autoradiographic assay.     

Cholecystoduodenoplasty for high-output duodenal fistula.

External duodenal fistulae from sutured duodenal ulcer perforation sites are difficult to manage and most patients succumb to septicemia and undernutrition. This is due to failure of closure of the perforation site in the duodenum. Most techniques described in the past to facilitate closure have failed to give satisfactory results. We have devised a new procedure where the duodenal ulcer perforation is closed by mobilizing the gall bladder. A hole is made in the fundus of the gall bladder and it is anastomosed to the freshened edges of the duodenal opening. We have treated six patients by this technique. In five patients the leak was satisfactorily sealed. Three patients died - one due to persistent leak and two due to jejunostomy leak.     

Mitochondrial complex I inhibition in Parkinson's disease: how can curcumin protect mitochondria?

Selective damage of mitochondrial complex I within the dopaminergic neurons of the substantia nigra is the central event during Parkinson disease. Peroxynitrite is one of the important free radicals probably mediating complex I damage. Peroxynitrite inhibits brain complex I mainly by 3-nitrotyrosine and nitrosothiol formation, but how these modifications alter the structure-function relation of complex I is unclear. Curcumin pretreatment protects brain mitochondria against peroxynitrite in vitro by direct detoxification and prevention of 3-nitrotyrosine formation and in vivo by elevation of total cellular glutathione levels. These results suggest a potential therapeutic role for curcumin against nitrosative stress in neurological disorders.