Accuracy of tibial positioning in the frontal plane: a prospective study comparing conventional and innovative techniques in total knee arthroplasty.

BACKGROUND: Coronal alignment of the tibial component determines functional outcome and survival in total knee arthroplasty (TKA). Innovative techniques for tibial instrumentation have been developed to improve accuracy and reduce the rate of outliers. METHODS: In a prospective study, 300 patients were allocated to four different groups using a randomization process (two innovative and two conventional) techniques of tibial instrumentation (conventional: extramedullary, intramedullary; innovative: navigation and patient-specific instrumentation (PSI); n = 75 for each group). The aims were to reconstruct the medial proximal tibial angle (MPTA) to 90° and the mechanical tibio-femoral axis (mTFA) to 0°. Both angles were evaluated and compared between all groups three months after the surgery. Patients who presented with a postoperative mTFA > 3° were classified as outliers. RESULTS: The navigation and intramedullary technique both demonstrated that they were significantly more precise in reconstructing a neutral mTFA and MPTA compared to the other two techniques. The odd's ratio (OR) for producing outliers was highest for the PSI method (PSI OR = 5.5, p < 0.05; extramedullary positioning OR = 3.7, p > 0.05; intramedullary positioning OR = 1.7, p > 0.05; navigation OR = 0.04, p < 0.05). We could only observe significant differences between pre- and postoperative MPTA in the navigation and intramedullary group. The MPTA showed a significant negative correlation with the mTFA in all groups preoperatively and in the extramedullary, intramedullary and PSI postoperatively. CONCLUSION: The navigation and intramedullary instrumentation provided the precise positioning of the tibial component. Outliers were most common within the PSI and extramedullary technique. Optimal alignment is dependent on the technique of tibial instrumentation and tibial component positioning determines the accuracy in TKA since mTFA correlated with MPTA pre- and postoperatively.

Correction of excessive intraarticular varus deformities in total knee arthroplasty is associated with deteriorated postoperative ankle function.

PURPOSE: The aim of this study was to demonstrate, whether the degree of limb alignment correction in varus knee osteoarthritis correlated with an increase in ankle symptoms and to define a cut-off value concerning the degree of correction above which to expect ankle problems. METHODS: Ninety-nine consecutive patients with preoperative intraarticular varus knee deformities who underwent total knee arthroplasty were retrospectively analyzed. Patients were examined clinically (Knee Society Score, Forgotten Joint Score, Foot Function Index, Range of Motion of the knee and ankle joint, pain scales) as well as radiologically. The mean follow-up time was 57 months. RESULTS: The degree of operative limb alignment correction strongly correlated with the Foot Function Index (R = 0.91, p < 0.05). Given this, higher degrees of knee malalignment corrections were associated with worse postoperative outcomes in the knee and ankle joint-despite postoperative improved joint line orientations. Subsequently, a cut-off value for arthritic varus deformities (14.5°) could be calculated, above which the prevalence of ankle symptoms increased manifold [OR = 15.6 (3.2-77.2 95% CI p < 0.05)]. Furthermore, ROM restrictions in the subtalar joint were associated with a worse outcome in the ankle joint. CONCLUSIONS: When correcting excessive intraarticular varus knee osteoarthritis, surgeons have to be aware of possible postoperative ankle symptoms and should consider ankle deformities or decreased subtalar ROM before operative procedures. LEVEL OF EVIDENCE: III.

[Surgical treatment of de-novo scoliosis]. / Operative Therapie der degenerativen Lumbalskoliose.

BACKGROUND: De-novo scoliosis is most commonly associated with chronic back pain and in 70 % of cases with neurological symptoms of the lower extremities. In recent literature, the occurrence and severity of segmental lateral listhesis has been discussed as being an important prognostic factor of sagittal and frontal deformity progression. In general, operative interventions in patients with de-novo scoliosis are associated with a high rate of complications. Therefore, conservative treatment modalities are recommended at early stages of the disease. If conservative management fails and a sufficient reduction of the patient's symptoms cannot be achieved, depending on the symptoms, a selective decompression, short-segment fusion or long-instrumented reduction and fusion are indicated. Additionally to the patient's symptoms, specific imaging diagnostics are necessary to develop an adequate surgical treatment strategy. TREATMENT: Selective decompression without fusion is indicated in patients with a fixed deformity and primarily neurologic pain or deficits. In conditions of a focal pathology as cause of significant low back pain and/or neurologic symptoms at early stages of deformity, a short segment fusion is the treatment of choice. However, short-segment fusion as a less-invasive procedure must not be performed in biplanar unbalanced patients and/or advanced de-novo scoliosis. In advanced degenerative de-novo scoliosis a long-segment reposition and fusion following an alignment correction are needed. Standardized pre-operative planning and perioperative management are highly critical to the post-operative success. CONCLUSION: All operative treatment strategies in patients with de-novo scoliosis can be successful but they require sophisticated and individual surgical indication.

[Characteristics of neuromuscular scoliosis]. / Besonderheiten neuromuskulärer Skoliosen.

Usually, neuromuscular scolioses become clinically symptomatic relatively early and are rapidly progressive even after the end of growth. Without sufficient treatment they lead to a severe reduction of quality of life, to a loss of the ability of walking, standing or sitting as well as to an impairment of the cardiopulmonary system resulting in an increased mortality. Therefore, an intensive interdisciplinary treatment by physio- and ergotherapists, internists, pediatricians, orthotists, and orthopedists is indispensable. In contrast to idiopathic scoliosis the treatment of patients with neuromuscular scoliosis with orthosis is controversially discussed, whereas physiotherapy is established and essential to prevent contractures and to maintain the residual sensorimotor function.Frequently, the surgical treatment of the scoliosis is indicated. It should be noted that only long-segment posterior correction and fusion of the whole deformity leads to a significant improvement of the quality of life as well as to a prevention of a progression of the scoliosis and the development of junctional problems. The surgical intervention is usually performed before the end of growth. A prolonged delay of surgical intervention does not result in an increased height but only in a deformity progression and is therefore not justifiable. In early onset neuromuscular scolioses guided-growth implants are used to guarantee the adequat development. Because of the high complication rates, further optimization of these implant systems with regard to efficiency and safety have to be addressed in future research.

Tensile strength of flexor tendon repair using barbed suture material in a dynamic ex vivo model.

The purpose of this study was to compare two sutures; a knotted polydioxane with a knotless barbed in a 4-strand Kirchmayr-Kessler suture technique. Human flexor digitorum tendons were separated into four groups. Group 1 - polydioxane; Group 2 - barbed suture; Group 3 and 4 - same as group 1 and 2 with an additional peripheral running suture. In each group the repaired tendons were subjected to linear and cyclical loads. No difference in maximum tensile strength after linear and cyclical force could be detected between the knotted polydioxane suture and the knotless barbed suture. On linear force tests an additional circumferential repair increased the maximum tensile strength of both sutures. Cyclical force loading did not lead to a reduction of maximum strength. Following linear and cyclical loading the 4-strand barbed suture achieved maximum tensile strengths comparable to the 4-strand repair using the polydioxane suture. Barbed suture repair may offer the advantage of knotless suture techniques.

[Supination external rotation lesions of the ankle joint in osteoporotic lower leg specimens. Experimental induction and review of the literature]. / Die Supinations-Eversions-Verletzung des OSG in osteoporotischen Unterschenkelpräparaten. Experimentelle Induktion und Literaturübersicht.

BACKGROUND: Knowledge of the pathomechanism and the detailed extent of ankle joint lesions determines adequate therapy and success of treatment. MATERIAL AND METHODS: Supination external rotation lesions were induced in 29 human cadavera with a testing apparatus; 27 of these specimens were from elderly women. Bone mineral density was measured. The literature review includes experimental studies of this fracture entity. RESULTS: We induced stage II in 42%; applying an additional lateral force on the fibula raised the incidence. The syndesmosis stayed intact in 50% although the fibula fractured at the level of the tibial plafond. Stage IV lesions were registered in 25%. The overall low bone mineral density showed a positive correlation to the angle at which the fibula fracture occurred. CONCLUSIONS: We reproduced supination external rotation lesions according to Lauge-Hansen in osteoporotic ankles. There is a certain discrepancy between the obligatory lesion of the inferior anterior tibiofibular syndesmosis at stage II according to Lauge-Hansen, as we observed an intact syndesmosis in 50% at stage II. Stage IV defining medial malleolar fractures were reproduced after Lauge-Hansen and Michelson et al.

[Propeller flaps: the reliability of preoperative, unidirectional Doppler sonography]. / Propeller-Lappenplastiken: die Reliabilität der präoperativen, unidirektionalen Dopplersonografie.

BACKGROUND: Propeller flaps represent an elegant and reliable method for soft-tissue reconstruction of the extremities and trunk, obviating the need for free tissue transfer. Preoperative localisation of perforators adjacent to the defect is important regarding the pivot point and length of the flap. Most commonly unidirectional Doppler sonography is used. The reliability of this method regarding propellerflaps has not thoroughly been evaluated. The aim of this study is to assess the positive predictive value of this method for planning propeller flaps. PATIENTS AND METHOD: In a total of 68 patients, soft-tissue reconstruction using propeller flaps was planned with unidirectional Doppler sonography. Defects were located on the lower extremity in 48 cases, the buttock area in 15 cases and the trunk in 5 cases. RESULTS: In 12 cases no adequate perforators were located intraoperatively despite a positive Doppler signal. In the lower extremity Doppler produced a false-positive result in 21% of the cases, whereas in the buttock region only 13% false positives result were found. The positive predictive value overall was 82%. When no perforator was located, flap coverage was achieved using the reverse sural artery flap in 6 cases, the free peroneal artery perforator flap in 3 cases, local advancement flaps in 2 cases and skin grafting in 1 case. DISCUSSION: The reliability of unidirectional Doppler sonography is inadequate for localisation and selection of the dominant perforator when planning propeller flaps. A high rate of false-positive results needs to be anticipated especially distally in the extremities. In 18% of cases an alternative surgical plan was required to achieve soft tissue coverage. We recommend using colour duplex sonography for a more reliable preoperative localisation of perforators.

Specific detection of cyclobutane pyrimidine dimers in phytoplankton DNA by a non-radioactive assay based on T4-endonuclease V digestion.

The effect of artificial and natural UV irradiation on DNA in marine phytoplankton Isochrysis galbana monoculture was investigated. The presence of cyclobutane pyrimidine dimers (CPDs) in unlabelled I. galbana DNA was detected by a non-radiometric alkaline filter elution assay after T4-endonuclease V digestion. The quantity of CPDs was estimated by alkaline agarose gel electrophoresis. Precise determination of the amount of DNA in the presence of I. galbana pigments was achieved by oxazole yellow homodimer (YOYO) dye. T4-endonuclease V-sensitive sites frequency (ESS/kb), measured after exposure to 2-40 kJ m(-2) of artificial UV light, increased in a dose-dependent manner. Twelve hours after irradiation cell culture growth was disrupted, and 50% of initial DNA damage in the cells was observed. After 1 h of sunlight exposure, the incidence of CPDs increase significantly. Prolonged exposition to sunlight decrease CPDs incidence due to efficiency of I. galbana DNA repair mechanisms. The presence of water-soluble crude oil fraction (WSOF) affected DNA repair efficiency resulting in accumulation of CPDs in I. galbana DNA.

DNA damage susceptibility and repair in correlation to calendric age and longevity.

In two mouse strains, SAM P (senescence acceleration prone) and SAM R (senescence acceleration resistant), of different longevities, with a ratio of P/R=1:2), the DNA status in the course of aging has been investigated using the DNA Alkaline Filter Elution (AFE) technique. Six different organs (brain, liver, heart, lung, intestine, and muscle) have been used in each of the four animals of a given age. Earlier it had been shown, that DNA is damaged the more the higher the age of the animal. DNA damage susceptibility, measured after exposure of organ pieces to nitroquinoline-N-oxide (NQO), is also significantly increased at higher ages, while repair, measured of NQO damaged tissue after 3 h incubation in full medium is significantly reduced. In the strain with shorter longevity the damage increments and the repair deficiencies are drastically deviating from those with higher longevity. These findings of strong coupling of the DNA status to aging as well as longevity suggest causative relations.

Age-associated DNA damage is accelerated in the senescence-accelerated mice.

We investigated how the DNA status correlates with the aging process in organisms, in different organs and in tissues using two inbred strains of mice, which are genetically related but have different senescence patterns. The SAMP1 mice belong to an accelerated senescence-prone and short lived strain, the other, SAMR1 mice are from an accelerated senescence-resistant and long lived strain. Using the alkaline filter elution technique, pieces of tissues from six organs: lung, intestine, liver, brain, muscle, and heart have been examined for DNA damage, mainly DNA single strand breaks. It was shown that in newborns the DNA damage is minimal, and it was increased significantly with calendric age in all organs in both strains. Although the correlation of DNA damage with aging differed in the different six organs, damage was significantly higher in SAMP1 mice than SAMR1 mice at later life in all organs. This is another remarkable example for the strong correlation of DNA damage and aging process, especially with senescence acceleration.

Evaluation of the SOS/umu-test post-treatment assay for the detection of genotoxic activities of pure compounds and complex environmental mixtures.

This study presents an evaluation of the SOS/umu-test after introducing an additional dilution and incubation in the post-treatment assay. This treatment reduces the influence of coloured test compounds that otherwise affect the colorimetric determination of the beta-galactosidase activity and the bacterial growth measurement during the testing of complex environmental samples. The post-treatment assay significantly increased the beta-galactosidase activity and consequently the enzyme induction ratios at higher doses of model genotoxins 4-nitroquinoline-N-oxide, N-methyl-N'-nitro-N-nitrosoguanidine, 2-aminoanthracene, benzo(a)pyrene with low or no effect on the sensitivity of the test itself. On the other hand tests of environmental extracts indicated significant increases in sensitivity after additional incubation. 4-Nitroquinoline-N-oxide treatments of bacteria in the test affected cell division and caused filamentous growth. The size of filamentous bacteria and incidence rate of the length categories was positively correlated with the concentrations of genotoxins. Presence of filamentous tester bacteria proved induction of SOS response and genotoxic activity of environment samples in SOS/umu-test.

Assessment of DNA-protein crosslinks in the course of aging in two mouse strains by use of a modified alkaline filter elution applied to whole tissue samples.

Two different mouse strains have been used for determination of age dependence of DNA-protein crosslinks by alkaline filter elution: a long lived laboratory strain, NMRI and an accelerated senescence-prone, short lived strain, SAMP1. Five organs were selected: Brain, kidney, lung, heart and liver. Remarkably in all five organs of short lived SAMPI mice crosslinks increased significantly with age. In NMRI however only in brain and heart a significant rise in old age has been observed, while in the other organs there was no increase in DNA-protein crosslinking. Appreciable mitotic activity which is lacking in brain and heart could be the reason for this difference. Poor repair in all five organs could be an important component for the multiple ailments and shortened life span in SAMP1 mice.

The influence of radiation and chemotherapy-related DNA strand breaks on carcinogenesis: an evaluation.

PURPOSE: DNA strand breaks are believed to induce carcinogenesis. This study was conducted to analyze induction and repair of irradiation- and chemotherapy-related strand breaks in vitro. METHODS: Friend Leukemia cells were exposed to irradiation and various chemotherapeutic agents at different doses and concentrations. Occurrence of strand breaks was determined fluorometrically, measuring the rate of DNA unwinding immediately after exposure and 24 hours later. RESULTS: The amount of double-stranded DNA decreased significantly for irradiation, doxorubicin, dactinomycin and etoposide (p < or = 0.05, t-test). After 24 hours free of exposure, the persistent damage was detectable for all of these agents but not for irradiated cells, with DNA strand breaks being decreased for etoposide, unchanged for doxorubicin and increased for methotrexate as well as for dactinomycin. CONCLUSIONS: Severe DNA damage is induced by various chemotherapeutic agents and by irradiation. While repair of chemotherapy-related strand breaks may remain incomplete or prolonged for some chemotherapeutic agents, repair of radiation induced strand breaks is faster and more complete. Therefore chemotherapy-related carcinogenesis may partially be explained by prolonged persistence of DNA strand breaks.

A microplate assay for DNA damage determination (fast micromethod).

A rapid and convenient procedure for DNA damage determination in cell suspensions and solid tissues on single microplates was developed. The procedure is based on the ability of commercially available fluorochromes to interact preferentially with dsDNA in the presence of ssDNA, RNA, and proteins at high pH (>12.0), thus allowing direct measurements of DNA denaturation without sample handling or stepwise DNA separations. The method includes a simple and rapid 40-min sample lysis in the presence of EDTA, SDS, and high urea concentration at pH 10, followed by time-dependent DNA denaturation at pH 12.4 after NaOH addition. The time course and the extent of DNA denaturation is followed in a microplate fluorescence reader at room temperature for less than 1 h. The method requires only 30 ng DNA per single well and could conveniently be used whenever fast analysis of DNA integrity in small samples has to be done, e.g., in patients' lymphocytes after irradiation or chemotherapy (about 3000 cells per sample), in solid tissues or biopsies after homogenization (about 25 microg tissue per well), or in environmental samples for genotoxicity assessment.

Increase of sensitivity and validity of the SOS/umu-test after replacement of the beta-galactosidase reporter gene with luciferase.

The SOS/umu-test with Salmonella typhimurium TA1535/pSK1002 as tester strain is a rapid and valuable bacterial assay for screening of umuC-dependent mutagenic potential of chemical compounds and chemicals relevant to environmental pollution. The initial assay was modified by replacing the beta-galactosidase reporter gene with luciferase. Thereby, the sensitivity of the umu-test was increased significantly and the susceptibility to intensively coloured solutions was reduced. The alternative enzyme assay in the modified umu-test (umu-Luc) represents an independent method which allows to confirm the colorimetric results obtained with the original SOS/umu-test system (umu-Gal) by measuring the beta-galactosidase activity. It has been proved that for several genotoxins an increased induction rate could be achieved by applying the new umu-Luc test.

DNA status in brain and heart as prominent co-determinant for life span? Assessing the different degrees of DNA damage, damage susceptibility, and repair capability in different organs of young and old mice.

Alkaline filter elution has been modified by a freeze-grinding step that allows the evaluation of the DNA status of whole tissue, including mouse tail cross-sections, with only small additional artefacts. Four to seven different organs from individually coordinated female NMRI mice, rated as young when 2-3 months, and as old when 24-27 months, of age, have been used. Tissues of individual mice differ significantly in their DNA status. Alkali-labile sites are relatively rare and differ in amount in the different organs in the young. They show significant increases in the old, reaching the highest values in the brain and the heart. Proteinase K dependent DNA-protein cross-links are not prominent nor are they increased with age in some organs, except in the brain and the heart. DNA damage susceptibility was measured after application of 3.5 microM nitoquinolin-N-oxide to 15 mg fresh. tissue pieces for 90 min. The susceptibility is large and varying in wide ranges in the different organs. Upon 3 h post-exposure incubation in full medium all samples showed DNA repair, the young reach nearly complete repair in the lung, while repair, generally, in the old is significantly decreased. In old brain and heart it is even near zero. This together with high values in alkali-labile sites and protein-DNA cross-linking suggests that these two organs may act as pacemakers and play a role as prominent co-determinants for the life span of the species.

Increased genotoxicity of acetylaminofluorene by modulators of multixenobiotic resistance mechanism: studies with the fresh water clam Corbicula fluminea.

The presence of a 'multixenobiotic resistance' [MXR] mechanism in gills of the freshwater clam Corbicula fluminea was investigated. Western blot analyses of membrane vesicles from gills, applying antibodies to vertebrate P170 multidrug resistance (MDR) protein, revealed a 135 kDa immunoreactive protein. Verapamil caused a reduction of 3H-vincristine (3H-VCR) binding onto vesicles from clam. Exposure of clams to 3H-VCR in the presence of verapamil or staurosporine (STP) enhanced the accumulation of 3H-VCR over control values. Furthermore, clams were exposed instead to VCR, to a model carcinogen, 2-acetylaminofluorene (AAF), to determine the verapamil- and STP-dependent increase of single-strand breaks (SSBs) in DNA from gills of this organism. Verapamil caused no or little increase of SSBs induced by exposure to 0.01 or 0.10 microM AAF, respectively, as measured by the alkaline elution technique. In contrast, in the presence of STP a highly significant and dose-dependent enhancement of AAF-mediated SSBs was measured already at exposure to 0.01 microM AAF. These data indicate (i) that the clam C. fluminea is provided with a P-glycoprotein-like element of the MDR-mechanism, (ii) that this system can be poisoned by chemosensitizers such as verapamil and STP, (iii) the role of protein kinase C in the regulation of MXR function and (iv) the importance of the MXR modulators for the assessment of ecotoxicological effects of pollutants.

Nonradiometric detection of DNA crosslinks in mussel hemolymph by alkaline elution.

The use of bleomycin-Fe(II) complex in the determination of DNA crosslinks by alkaline elution was investigated for the purpose of developing a simple nonradiometric method applicable for detection of DNA damage in marine organisms. The assay involves preparation of active bleomycin-Fe(II) complex and its application in the washing step of the original alkaline elution procedure. Treatment of cell-free DNA from Friend leukemia cells and mussel hemolymph with bleomycin-Fe(II) complex directly on the filter resulted in a concentration-dependent strand scission response with excellent correlation (r = 0.94 and 0.98, respectively). The procedure was validated by determination of DNA cross-links in mussels injected with mitomycine C and formaldehyde.

Fractionation of DNA from marine invertebrate (Maja crispata, Mytilus galloprovincialis) haemolymph by alkaline elution.

1. An alkaline elution procedure for the detection of DNA damage in marine invertebrate haemolymph has been developed. 2. Provided that three criteria are optimized, such as buffer composition, small filter pores (0.22 microns GVWP 025 00, Millipore), and optimal amounts of haemolymph applied, flow rates may be changed within the range of 0.2 ml/min to 0.05 ml/min without adverse back-pressure on the filter and without blocking filter pores. 3. Under optimal conditions, 70% of mussel haemolymph DNA, and 80% of crab haemolymph DNA will be retained on the filter after 6 hr of elution, indicating shorter DNA in mussel haemolymph. 4. The technique is applicable for testing the in vivo effects of different compounds on DNA in marine invertebrates, and to measurements of DNA damage in naturally exposed mussels. 5. This argues an important case for the use of alkaline elution technique for assessment of environmental genotoxicity, and especially for investigation of DNA damage in different marine organisms which cover a broad range in their DNA molecular weights.