Der Einfluss von knöchernen Glenoid Rekonstruktionsverfahren auf die Weichteilintegrität der Schulter

Introduction: Glenoid bone loss resulting from fractures or erosions caused by recurrent shoulder dislocations is a common cause of anterior shoulder instability. If the bony defect reaches a critical size, soft tissue surgery such as labrum refixation cannot achieve sufficient stability. In these cases, an osseous glenoid reconstruction is indicated. Basically, a distinction is made between two techniques, that of the coracoid transfer and that of the free bone graft. The following scientific work relates to two special subtypes of these surgical techniques: the screw-fixed coracoid transfer according to Latarjet and the implant-free J-shaped iliac crest bone graft transfer (ICBGT). Although studies have shown that the clinical results of both techniques are comparable, a significant reduction in internal rotation has been described after the Latarjet procedure. In this thesis the effects of the Latarjet procedure and the ICBGT on the soft tissue integrity of the shoulder were examined and possible causes for the restricted mobility were analyzed. We hypothesized that the subscapularis muscle, which is important for internal rotation, is significantly more affected by the Latarjet procedure compared to the ICBGT. Methods: The integrity of the rotator cuff (subscapularis, infraspinatus and teres minor) was examined preoperatively and in a two-year follow-up using CT-data from a previous prospective randomized study (26 patients following Latarjet versus 26 ICBGT). Both, the degree of fatty muscle infiltration according to the Goutallier classification and a quantitative measurement of the attenuation (Hounsfield units) in relation to the average muscle area were determined. The tendon thickness of the subscapularis muscle was measured at the musculotendinous junction compared to the infraspinatus tendon thickness at the same level. In addition, an analysis of the bone resorption of the respective grafts and the resulting routing of the subscapularis was carried out. Results: While the preoperative values of both groups with regard to fatty muscle infiltration and tendon thickness were comparable, there was a significant increase of fatty infiltration of the subscapularis muscle and thinning of the tendon in the Latarjet group in the follow-up compared to the ICBGT group. Conclusion: The hypothesis could thus be proven. This study shows that the subscapularis muscle is structurally impaired postoperatively after the Latarjet procedure. One of the main reasons might be a mechanical conflict between the protruding screw heads, which is caused by partial resorption of the transplant.Einleitung: Ein Knochenverlust des Glenoids durch Frakturen oder Erosionen bei wiederholten Schulterluxationen ist eine häufige Ursache der vorderen Schulterinstabilität. Erreicht der knöcherne Defekt eine kritische Größe kann mit einem Weichteileingriff wie zum Beispiel einer Labrumrefixierung nicht ausreichend Stabilität erzielt werden. In diesen Fällen ist eine knöcherne Glenoidrekonstruktion indiziert. Grundsätzlich werden zwei Techniken, die des Korakoidtranfers und, die des freien Knochentransplantates unterschieden. Die durchgeführte wissenschaftliche Arbeit bezieht sich auf zwei spezielle Unterarten dieser Operationstechniken: den mit Schrauben fixierten Korakoidtransfer nach Latarjet und die implantatfreie J-Span Beckenkammplastik. Obwohl in Studien gezeigt wurde, dass die klinischen Ergebnisse beider Techniken vergleichbar sind, wurde nach dem Latarjet Verfahren eine signifikante Reduktion der Innenrotation beschrieben. In dieser Arbeit wurden die Auswirkungen des Latarjet Verfahrens und der J-Span Plastik auf die Weichteilintegrität der Schulter untersucht und mögliche Ursachen für diese Bewegungseinschränkung analysiert. Wir stellten die Hypothese auf, dass der für die Innenrotation wichtige Muskulus Subskapularis durch das Latarjet Verfahren im Vergleich zur J-Span Plastik mehr beeinträchtigt wird. Methoden: Anhand von CT-Daten, die im Rahmen einer früheren prospektiv randomisiert kontrollierten Studie erhoben wurden, wurde die Integrität der Rotatorenmanschette (M. Subskapularis, M. Infraspinatus, und M. Teres minor) präoperativ und im Follow-up nach zwei Jahren untersucht (26 Patienten nach Latarjet gegen 26 nach J-Span Plastik). Dabei wurde sowohl der Grad der Verfettung entsprechend der Goutallier Klassifikation als auch durch eine quantitative Messung der Strahlenabschwächung (Hounsfield units) in Relation zur Muskeldurchschnittsfläche bestimmt. Die Sehnendicke des Subskapularis wurde am muskulotendinösen Übergang im Vergleich zur Sehnendicke des M. Infraspinatus an selbiger Stelle gemessen. Zusätzlich erfolgte eine Analyse der Knochenresorption der entsprechenden Transplantate und die darauf resultierende Umleitung des M. Subskapularissehnenzugs. Ergebnisse: Während die präoperativ erhobenen Werte beider Gruppen in Bezug auf die Muskelverfettung und die Sehnendicke vergleichbar waren, zeigte sich eine signifikante Zunahme der Verfettung des M. Subskapularis als auch eine Ausdünnung der Sehne in der Latarjet Gruppe im Follow-up im Vergleich zur J-Span Gruppe. Schlussfolgerung: Die Hypothese konnte somit bestätigt werden. Diese Studie zeigt, dass der Subskapularis durch das Latarjet Verfahren strukturell beeinträchtigt wird. Einer der Hauptgründe könnte ein mechanischer Konflikt der hervorstehenden Schraubenköpfe sein, der durch eine partielle Resorption des Transplantates entsteht

Maximum Waring Ranks of Monomials and Sums of Coprime Monomials

We show that monomials and sums of pairwise coprime monomials in four or more variables have Waring rank less than the generic rank, with a short list of exceptions. We asymptotically compare their ranks with the generic rank

The effect of omega-3 fatty acids on central nervous system remyelination in fat-1 mice

Background There is a large body of experimental evidence suggesting that omega-3 (n-3) polyunsaturated fatty acids (PUFAs) are capable of modulating immune function. Some studies have shown that these PUFAs might have a beneficial effect in patients suffering form multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the central nervous system (CNS). This could be due to increased n-3 PUFA-derived anti-inflammatory lipid mediators. In the present study we tested the effect of an endogenously increased n-3 PUFA status on cuprizone-induced CNS demyelination and remyelination in fat-1 mice versus their wild-type (wt) littermates. Fat-1 mice express an n-3 desaturase, which allows them to convert n-6 PUFAs into n-3 PUFAs. Results CNS lipid profiles in fat-1 mice showed a significant increase of eicosapentaenoic acid (EPA) levels but similar docosahexaenoic acid levels compared to wt littermates. This was also reflected in significantly higher levels of monohydroxy EPA metabolites such as 18-hydroxyeicosapentaenoic acid (18-HEPE) in fat-1 brain tissue. Feeding fat-1 mice and wt littermates 0.2% cuprizone for 5 weeks caused a similar degree of CNS demyelination in both groups; remyelination was increased in the fat-1 group after a recovery period of 2 weeks. However, at p = 0.07 this difference missed statistical significance. Conclusions These results indicate that n-3 PUFAs might have a role in promotion of remyelination after toxic injury to CNS oligodendrocytes. This might occur either via modulation of the immune system or via a direct effect on oligodendrocytes or neurons through EPA- derived lipid metabolites such as 18-HEPE

The inter-individual anatomical variation of the trochlear notch as a predisposition for simple elbow dislocation

Purpose: Besides the multi-layered capsule-ligamentous complex of the elbow joint the high bony congruence in the ulnohumeral joint contributes to elbow stability. Therefore, we assume that specific anatomical configurations of the trochlear notch predispose to dislocation. In case of ligamentous elbow dislocation both conservative and surgical treatment is possible without a clear treatment algorithm. Findings of constitutional bony configurations could help deciding for the best treatment option. Methods: In this retrospective matched-pair analysis we compared MRI imaging from patients sustaining a primary traumatic elbow dislocation (instability group) with patients suffering from chronic lateral epicondylitis (control group), treated between 2009 and 2019. Two independent observers measured different anatomical landmarks of the trochlear notch in a multiplanar reconstructed standardized sagittal trochlear plane (SSTP). Primarily, opening angle and relative depth of the trochlear notch were determined. After adjustment to the proximal ulnar rim in the SSTP, coronoid and olecranon angle, the articular angle as well as the ratio of the tip heights of the trochlear notch were measured. Results: We compared 34 patients in the instability group (age 48 +/- 14 years, f/m 19/15) with 34 patients in the control group (age 47 +/- 16 years, f/m 19/15). Instability group showed a significantly larger opening angle (94.1 degrees +/- 6.9 degrees vs. 88.5 degrees +/- 6.9 degrees, p = 0.0002), olecranon angle (60.9 degrees +/- 5.3 degrees vs. 56.1 degrees +/- 5.1 degrees, p < 0.0001) and articular angle (24.7 degrees +/- 6.4 degrees vs. 22.3 degrees +/- 5.8 degrees, p = 0.02) compared to the control group. Measuring the height from the coronoid (ch) and olecranon (oh) tip also revealed a significantly larger tip ratio (tr = ch/oh) in the instability group (2.7 +/- 0.8 vs. 2.2 +/- 0.5, p < 0.0001). The relative depth (61.0% +/- 8.3% vs. 62.7% +/- 6.0%, p = 0.21) of the trochlear notch as well as the coronoid angle (32.8 degrees +/- 4.5 degrees vs. 31.7 degrees +/- 5.2 degrees, p = 0.30) showed no significant difference in the instability group compared to the control group. The interrater reliability of all measurements was between 0.83 and 0.94. Conclusion: MRI of patients with elbow dislocation show that there seems to be a bony anatomical predisposition. According to the results, it seems reasonable to include predisposing bony factors in the decision-making process when surgical stabilization and conservative treatment is possible. Further biomechanical studies should prove these assumptions to generate critical bony values helping surgeons with decision making

The role of serum C-reactive protein in the diagnosis of periprosthetic shoulder infection

Introduction: There is a paucity of literature regarding serum C-reactive protein (CRP) in the evaluation of a shoulder periprosthetic joint infection (PJI). The purpose of the current study was to establish cutoff values for diagnosing shoulder PJI and evaluate the influence of the type of infecting microorganism and the classification subgroups according to last proposed International Consensus Meeting (ICM) criteria on the CRP level. Materials and methods: A retrospective analysis of all 136 patients, who underwent septic or aseptic revision shoulder arthroplasty in our institution between January 2010 and December 2019, was performed. Shoulder PJI was defined according to the last proposed definition criteria of the ICM. Serum CRP levels were compared between infected and non-infected cases, between infection subgroups, as well as between different species of infecting microorganisms. A receiver-operating characteristic (ROC) analysis was performed to display sensitivity and specificity of serum CRP level for shoulder PJI. Results: A total of 52 patients (38%) were classified as infected, 18 meeting the criteria for definitive infection, 26 for probable infection and 8 for possible infection. According to the ROC curve, an optimized serum CRP threshold of 7.2 mg/l had a sensitivity of 69% and specificity of 74% (area under curve = 0.72). Patients with definitive infection group demonstrated significantly higher median serum CRP levels (24.3 mg/l), when compared to probable, possible infection groups and PJI unlikely group (8 mg/l, 8.3 mg/l, 3.6 mg/l, respectively, p < 0.05). The most common isolated microorganism was Cutibacterium acnes in 25 patients (48%) followed by coagulase-negative staphylococci (CNS) in 20 patients (39%). Patients with a PJI caused by high-virulent microorganisms had a significantly higher median serum CRP level compared to patients with PJI caused by low-virulent microorganisms (48 mg/l vs. 11.3 mg/l, p = 0.04). Conclusions: Serum CRP showed a low sensitivity and specificity for the diagnosis of shoulder PJI, even applying cutoffs optimized by receiver-operating curve analysis. Low-virulent microorganisms and patients with probable and possible infections are associated with lower CRP levels compared to patients with definitive infection and infections caused by high-virulent microorganisms

Comparison of Structural Subscapularis Integrity After Latarjet Procedure Versus Iliac Crest Bone Graft Transfer

Background: Although clinical outcome scores are comparable after coracoid transfer procedure (Latarjet) and iliac crest bone graft transfer (ICBGT) for anterior shoulder instability with glenoid bone loss, a significant decrease in internal rotation capacity has been reported for the Latarjet procedure. Hypothesis: The subscapularis (SSC) musculotendinous integrity will be less compromised by ICBGT than by the Latarjet procedure. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively analyzed pre- and postoperative computed tomography (CT) scans at short-term follow-up of 52 patients (26 Latarjet, 26 ICBGT) previously assessed in a prospective randomized controlled trial. Measurements included the preoperative glenoid defect area and graft area protruding the glenoid rim at follow-up and tendon thickness assessed through SSC and infraspinatus (ISP) ratios. Fatty muscle infiltration was graded according to Goutallier, quantified with muscle attenuation in Hounsfield units, and additionally calculated as percentages. We measured 3 angles to describe rerouting of the SSC musculotendinous unit around the bone grafts. Results: SSC fatty muscle infiltration was 2.0% ± 2.2% in the Latarjet group versus 2.4% ± 2.2% in ICBGT (P = .546) preoperatively and showed significantly higher values in the Latarjet group at follow-up (5.3% ± 4.5% vs 2.3% ± 1.7%; P = .001). In total, 4 patients (15.4%) in the Latarjet group showed a progression from grade 0 to grade 1 at follow-up, whereas no changes in the ICBGT group were noted. The measured rerouting angle of the SSC muscle was significantly increased in the Latarjet group (11.8° ± 2.1°) compared with ICBGT (7.5° ± 1.3°; P < .001) at follow-up, with a significant positive correlation between this angle and fatty muscle infiltration (R = 0.447; P = .008). Ratios of SSC/ISP tendon thickness were 1.03 ± 0.3 in the Latarjet group versus 0.97 ± 0.3 (P = .383) in ICBGT preoperatively and showed significantly lower ratios in the Latarjet group (0.7 ± 0.3 vs 1.0 ± 0.2; P < .001) at follow-up. Conclusion: Although clinical outcome scores after anterior shoulder stabilization with a Latarjet procedure and ICBGT are comparable, this study shows that the described decline in internal rotation capacity after Latarjet procedure has a radiographic structural correlate in terms of marked thinning and rerouting of the SSC tendon as well as slight fatty degeneration of the muscle

Water extracts from Siberian thawing permafrost - from land to ocean

To better understand and quantify fluxes of dissolved elements upon permafrost thaw, water-soluble elements from Siberian permafrost samples covering a wide geographic range were determined by extraction. We measured the pH- and EC-values as well as the total dissolved major and secondary cation concentrations and anion concentrations for 270 water extracts from 12 different sites around the Laptev Sea. Cation concentrations were analyzed using inductively coupled plasma-optical emission spectrometry and anion concentrations by ion chromatography. Hydrogen carbonate concentrations were measured by potentiometric pH-value titration using an automatic titrator. Electrical conductivity and pH values were measured using a WTW MultiLab 540 multi-parameter device. As ground ice melts throughout Siberia with continued climate warming, drainage of the soils in many locations is improving and exposing mineral surfaces that were previously largely inert by their perennially frozen condition and unaffected by active weathering through seasonal wetting and drying cycles. Chemical analyses of water extracts allow an assessment of the potential interactions between mineral surfaces and pore melt water and the characteristics and biogeochemical and ecological consequences of the export of melt water from thawing permafrost. The (hydro-)chemical flux from permafrost sources into the riverine and marine realms is mainly defined by its source signatures and concentrations, which will be addressed in the present study. We compare our values with water data from lakes, rivers and the Arctic Ocean. The influence of terrestrial input from thawing permafrost including ground ice is expected to increase as coastal and river shore erosion as well as other permafrost degradation processes accelerate under Arctic warming and mobilize previously freeze-locked material. The increasing influx of dissolved elements influences transport and deposition processes in aquatic environments as well as nutrient supply, food chains and life cycles with largely understudied consequences for aquatic and coastal ecosystems in the Arctic

Candida dubliniensis candidemia in patients with chemotherapy-induced neutropenia and bone marrow transplantation.

The recently described species Candida dubliniensis has been recovered primarily from superficial oral candidiasis in HIV-infected patients. No clinically documented invasive infections were reported until now in this patient group or in other immunocompromised patients. We report three cases of candidemia due to this newly emerging Candida species in HIV-negative patients with chemotherapy-induced immunosuppression and bone marrow transplantation