Computer-assisted navigation for the intraoperative assessment of lower limb alignment in high tibial osteotomy can avoid outliers compared with the conventional technique

Purpose

Longterm outcomes after valgization high tibial osteotomy (HTO) to treat varus osteoarthritis seem to depend mainly on correction precision. Intraoperative assessment of leg alignment based on radiological visualization of the mechanical axis is difficult and its precision is limited. A promising approach to improving precision is to make use of navigation systems. The case–control study reported here involved the evaluation of patients whose varus osteoarthritis had been treated by open-wedge high tibial ostoetomy, and an analysis of the effect of computer-guided navigation on postoperative leg alignment.

Methods

Forty patients with medial varus osteoarthritis managed by open-wedge high tibial osteotomy using a surgical navigation system were included in the present study (Group 1). They were compared with a retrospective control group (Group 2) of 40 patients with respect to postoperative leg alignment, correlation of planned and definitive correction, and postoperative deviation from the Fujisawa point.

Results

The mean values for planned and definitive correction showed no significant differences for identical demographic data. As a percentage of the width of the tibial plateau the postoperative weight-bearing radiographs showed a mechanical line that intersected with the knee base line at the desired value of 62 % (Fujisawa point) in 58.8 % (SD ± 6.1) in Group 1 and in 58.6 % (SD ± 8.1) in Group 2. Despite similar mean values a significantly higher number of corrections were outside the reference area (n = 7) in the non-navigated group, whereby all corrections were within the desired range in the navigated group. There were no significant differences in operation time.

Conclusions

This study showed that the use of a navigation system can not increase the precision of the open-wedge HTO procedure in patients with varus osteoarthritis but it can eliminate the outliers of a well defined range.

Level of evidence

Case-control study, Retrospective comparative study, Level III.     

Interaction of high molecular weight kininogen, factor XII, and fibrinogen in plasma at interfaces

Using ellipsometry, anodized tantalum interference color, and Coomassie blue staining in conjunction with immunologic identification of proteins adsorbed at interfaces, we have previously found that fibrinogen is the main constituent deposited by plasma onto many man- made surfaces. However, the fibrinogen deposited from normal plasma onto glass and similar wettable materials is rapidly modified during contact activation until it can no longer be identified antigenically. In earlier publications, we have called this modification of the fibrinogen layer "conversion," to indicate a process of unknown nature. Conversion of adsorbed fibrinogen by the plasma was not accompanied by marked change in film thickness, so that we presumed that this fibrinogen was not covered but replaced by other protein. Conversion is now showen to be markedly delayed in plasma lacking high molecular weight kininogen, slightly delayed in plasma lacking factor XII, and normal in plasma that lack factor XI or prekallikrein. We conclude that intact plasma will quickly replace the fibrinogen it has deposited on glass-like surfaces by high molecular weight kininogen and, to a smaller extent, by factor XII. Platelets adhere preferentially to fibrinogen-coated surfaces; human platelets adhere to hydrophobic nonactivating surfaces, since on these, adsorbed firbinogen is not exchanged by the plasma. The adsorbed fibrinogen will be replaced on glass-like surfaces during surface activation of clotting, and platelets failing to find fibrinogen will not adhere.     

Chromosome 7 long arm deletion in myeloid disorders: a narrow breakpoint region in 7q22 defined by molecular mapping

The involvement of the erythropoietin (EPO), plasminogen activator inhibitor type I (PAI1), and multi-drug resistance (MDR2) genes located in chromosomal region 7q21-22 was studied in patients with myeloid disorders and with or without a chromosome 7 abnormality. Separated blood mononuclear cells and granulocytes from 21 patients were used in restriction fragment length polymorphism (RFLP) studies with gene- specific DNA probes. A marked weakness of one of the allelic bands was observed in granulocyte-derived DNA from heterozygous patients with monosomy 7. In four patients with a partial deletion of chromosome 7 long arm (7q-), marked weakness of an allelic band was observed in granulocyte-derived DNA with PAI1 probe (four heterozygous patients) and MDR2 probe (one heterozygous patient), implying deletion of these genes. In contrast, the EPO gene was not deleted in these patients, as demonstrated by the presence of two allelic bands of equal strength in granulocyte-derived DNA (two patients) or by gene dosage estimation (two patients). Two allelic bands of equal strength were also observed in three heterozygous patients with an arbitrary probe (pKV13) located in 7cen-q21.3. Unexpected hemizygosity or hybridization bands were not observed in any patient. We conclude that PAI1 and MDR2 are located distally of EPO in 7q22, and that none of these genes is commonly rearranged in myeloid disorders. The chromosome 7 long arm deletion breakpoint is located in a relatively narrow segment between the PAI1 and EPO genes in different patients. The deletion may involve a specific site in DNA, since the genetic distance between the PAI1 and EPO genes is only 3 cM.     

The somatotrophic system in patients with dilated cardiomyopathy: relation of insulin-like growth factor-1 and its alterations during growth hormone therapy to cardiac function

OBJECTIVE: Treatment with human recombinant growth hormone has yielded conflicting results in patients with congestive heart failure. In addition, growth hormone resistance has been reported in severe heart failure. Therefore, the purpose of this study was to evaluate the somatotrophic axis and effects of growth hormone on haemodynamics in patients with heart failure due to dilated cardiomyopathy. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: Fifty clinically-stable patients with moderate heart failure (mean left ventricular ejection fraction = 26 +/- 2%) due to dilated cardiomyopthy were examined. MEASUREMENTS: Patients were randomly assigned to treatment with placebo or 2 IU/d sc human recombinant growth hormone for a mean of 14 weeks. Cardiac size and function were evaluated by magnetic resonance imaging. Central haemodynamics were obtained by right heart catheterization. Measurements of plasma noradrenaline, serum insulin-like growth factor-1, and insulin-like growth factor binding protein-3 were performed by standard assays at baseline and at the end of the treatment period. RESULTS: The severity of heart failure as determined by stroke volume, left ventricular end diastolic diameter and plasma noradrenaline concentrations correlated significantly to baseline serum insulin-like growth factor-1 levels (each P < 0.05). The growth hormone-induced increase of insulin-like growth factor-1 predicted the changes in ejection fraction (P < 0.05). A significant increase in ejection fraction of 7% was observed in patients whose insulin-like growth factor-1 increased by more than the median increase in comparison to the patients with an increase below the median (+ 4.0 +/- 2.3% vs. - 3.0 +/- 1.8%; P = 0.03). CONCLUSIONS: Serum levels of insulin-like growth factor-1, reflecting growth hormone secretion, are diminished in relation to the severity of heart failure in patients with dilated cardiomyopathy. Growth hormone induced increases of insulin-like growth factor-1 of more than 77 ng/l caused significant improvement of ejection fraction.     

Isolated congenital tuberculosis otitis in a preterm infant

We report an unusual case of localized congenital tuberculosis otitis in a preterm infant. Unlike disseminated congenital cases, the manifestations of localized otitis are associated with a triad of signs: (i) regional lymphadenopathy in the absence of typical systemic features of tuberculosis; (ii) delayed onset of presentation; and (iii) refractory otitis unresponsive to conventional antimicrobial agents. The need for greater diligence in looking for neonatal tuberculosis is emphasized, especially in an ethnic or socioeconomic environment where the disease is prevalent. Congenital tuberculosis, otitis, preterm
PC Ng, Department of Paediatrics, Level 6, Clinical Sciences Building, Prince of Wales Hospital, Shatin, NT, Hong Kong     

Reconstruction of the upper stapes

Bei fehlendem Amboss und fehlendem Stapesoberbau, aber intakter und beweglicher Fu?platte wird die Schallleitungskette üblicherweise mittels einer Columella rekonstruiert. Das Verfahren ist unter audiologischen Aspekten nicht optimal und hat einige Risiken: je nach Material Fixation oder Extrusion der Prothese, evtl. auch Durchsto?ung der Fu?platte. Eine Methode zur Rekonstruktion des Stapesoberbaus w?re daher wünschenswert. Dies ist auch Thema der Originalarbeit “Rekonstruktion des Steigbügeloberbaus beim Meerschweinchen mit einer Biovitrokeramik und Silikonfolie” von P. Dost et al. auf den Seiten 1053–1056 in dieser Ausgabe der “HNO” [1]. Ob dies beim Menschen mittels bioaktiver Keramik m?glich ist, ist trotz erfolgreicher Meerschweinchen-Versuche zweifelhaft. Prof.Dr.M.Strohm Hals-Nasen-Ohren-Klinik am Evangelischen Diakonissen-Krankenhaus, Diakonissenstra?e 28, 76199 Karlsruhe