[Subscapularis tendon lesions. Anatomy, diagnosis and importance of arthroscopic treatment]

The subscapularis tendon is involved in up to 43% of arthroscopically treated rotator cuff lesions. Due to the close anatomic relationship, participation of the long head of the biceps and supraspinatus tendon is common. Subscapularis tendon lesions are often not primary diagnosed correctly. Using specific clinical tests and modern sectional imaging, the percentage of correct diagnoses can be increased. Convincing clinical results, advantages of minimally invasive surgery, and superior visualization compared to the open approach argue for arthroscopic treatment of subscapularis lesions. Awareness of the footprint allows anatomic reconstruction. In case of planned open treatment, arthroscopy should precede as particularly articular-sided lesions might be missed otherwise.

[Comparison of results after primary and secondary shoulder arthroplasty for proximal humeral fractures]

BACKGROUND

The purpose of this retrospective cohort study was to evaluate, compare and discuss the results and complications after primary and secondary shoulder arthoplasty in proximal humeral fractures.

PATIENTS AND METHODS

Thirteen consecutive patients (mean 76 years [range, 65-85] years) were at a mean of 29 (8-37) months after primary humeral head replacement (group 1), and 15 patients (mean 74 years [range, 43-80] years) at a mean of 18 (7-36) months after secondary shoulder arthoplasty (n = 8 anatomic prostheses, n = 7 reversed prostheses) due to complications/fracture sequelae (group 2) examined clinically and radiologically according to a standardised follow-up protocol. Patient satisfaction, the simple shoulder test (SST), the American shoulder elbow score (ASES) as well as the Constant score (CS) were assessed, and radiological parameters as well as complications analysed.

RESULTS

85 % of patients in group 1 and 73 % in group 2 were satisfied with the results. The SST did not show a significant difference between both groups. The adjusted ASES did not differ significantly with 70 (27-95)% in group 1 and 73 (28-100)% in group 2, as well as the adjusted CS with a mean of 53 (27-83)% in group 1 and of 49 (27-87)% in group 2. Radiological analysis resulted in a correctly centred prosthesis in 6/13 patients, and healed tuberosities in 7/13 of group 1. In group 2 4/8 anatomic prostheses were centered and 7/8 showed healed tuberosities. In the subgroup of the reversed prostheses 6/7 were centered, 3/7 patients had an inferior "notching". The rate of complications and revisions were 2/13 (15 %) in group 1 and 1/15 (7 %) in group 2.

CONCLUSION

In summary, the functional results did not differ significantly between primary and secondary shoulder arthroplasty after proximal humeral fractures. The relatively low expectation of elderly patients is reflected in a high rate of patient satisfaction in spite of moderate functional results. The primary humeral head replacement showed higher rates of complications and revisions compared to secondary arthroplasty.

The hydrophobic core of twin-arginine signal sequences orchestrates specific binding to Tat-pathway related chaperones

Redox enzyme maturation proteins (REMPs) bind pre-proteins destined for translocation across the bacterial cytoplasmic membrane via the twin-arginine translocation system and enable the enzymatic incorporation of complex cofactors. Most REMPs recognize one specific pre-protein. The recognition site usually resides in the N-terminal signal sequence. REMP binding protects signal peptides against degradation by proteases. REMPs are also believed to prevent binding of immature pre-proteins to the translocon. The main aim of this work was to better understand the interaction between REMPs and substrate signal sequences. Two REMPs were investigated: DmsD (specific for dimethylsulfoxide reductase, DmsA) and TorD (specific for trimethylamine N-oxide reductase, TorA). Green fluorescent protein (GFP) was genetically fused behind the signal sequences of TorA and DmsA. This ensures native behavior of the respective signal sequence and excludes any effects mediated by the mature domain of the pre-protein. Surface plasmon resonance analysis revealed that these chimeric pre-proteins specifically bind to the cognate REMP. Furthermore, the region of the signal sequence that is responsible for specific binding to the corresponding REMP was identified by creating region-swapped chimeric signal sequences, containing parts of both the TorA and DmsA signal sequences. Surprisingly, specificity is not encoded in the highly variable positively charged N-terminal region of the signal sequence, but in the more similar hydrophobic C-terminal parts. Interestingly, binding of DmsD to its model substrate reduced membrane binding of the pre-protein. This property could link REMP-signal peptide binding to its reported proofreading function.

Probing the interaction of the diarylquinoline TMC207 with its target mycobacterial ATP synthase

Infections with Mycobacterium tuberculosis are substantially increasing on a worldwide scale and new antibiotics are urgently needed to combat concomitantly emerging drug-resistant mycobacterial strains. The diarylquinoline TMC207 is a highly promising drug candidate for treatment of tuberculosis. This compound kills M. tuberculosis by binding to a new target, mycobacterial ATP synthase. In this study we used biochemical assays and binding studies to characterize the interaction between TMC207 and ATP synthase. We show that TMC207 acts independent of the proton motive force and does not compete with protons for a common binding site. The drug is active on mycobacterial ATP synthesis at neutral and acidic pH with no significant change in affinity between pH 5.25 and pH 7.5, indicating that the protonated form of TMC207 is the active drug entity. The interaction of TMC207 with ATP synthase can be explained by a one-site binding mechanism, the drug molecule thus binds to a defined binding site on ATP synthase. TMC207 affinity for its target decreases with increasing ionic strength, suggesting that electrostatic forces play a significant role in drug binding. Our results are consistent with previous docking studies and provide experimental support for a predicted function of TMC207 in mimicking key residues in the proton transfer chain and blocking rotary movement of subunit c during catalysis. Furthermore, the high affinity of TMC207 at low proton motive force and low pH values may in part explain the exceptional ability of this compound to efficiently kill mycobacteria in different microenvironments.

[How to become a trauma surgeon: analysis of the current situation and concepts for career development in the new common field of orthopaedics and trauma surgery--part I]

The lack of clinical residents especially in the surgical domains, including orthopaedics and trauma surgery, is not only omnipresent but also a topic of lively discussions. This lack originates from sociopolitical and healthcare policy issues as well as from a loss of attractiveness of all surgical disciplines. The loss is caused by the high workload and disadvantageous working hours especially in those disciplines with a high rate of emergencies, e.g. trauma surgery. Moreover, it is caused by the poorly structured and unpredictable period of residency. In order to anticipate the bottleneck in supply due to the lack of trainees, a number of structural and contextual measures have to be taken to improve both undergraduate und postgraduate surgical training. Due to the numerous facets of the topic the first part of this analysis refers to the period until the trainee decides on the field of training.A basic insight into the field of orthopaedics and trauma surgery can already be offered far before the period of medical studies itself. During undergraduate medical education the existing structures should be modified, the characteristics of the discipline should be emphasized and the charm of combining theory and practical skills should be highlighted in order to enhance student's perception of the discipline. This might begin during preclinical training and should be continued throughout clinical training and elective courses (basic wound care, TEAM approach, AO course for students and seminars for M.D. candidates). Contextual and structural improvements of the practical year are indispensable to arouse students' interest in our discipline. These options conjoined with the actual offers for students provided by our scientific society, such as guided tours during the annual congress, travelling grants and the recently inaugurated summer school, might provide the basis for clearly structured information and offer a distinct stimulus to apply for residency in our field.

ATP synthase in slow- and fast-growing mycobacteria is active in ATP synthesis and blocked in ATP hydrolysis direction

ATP synthase is a validated drug target for the treatment of tuberculosis, and ATP synthase inhibitors are promising candidate drugs for the treatment of infections caused by other slow-growing mycobacteria, such as Mycobacterium leprae and Mycobacterium ulcerans. ATP synthase is an essential enzyme in the energy metabolism of Mycobacterium tuberculosis; however, no biochemical data are available to characterize the role of ATP synthase in slow-growing mycobacterial strains. Here, we show that inverted membrane vesicles from the slow-growing model strain Mycobacterium bovis BCG are active in ATP synthesis, but ATP synthase displays no detectable ATP hydrolysis activity and does not set up a proton-motive force (PMF) using ATP as a substrate. Treatment with methanol as well as PMF activation unmasked the ATP hydrolysis activity, indicating that the intrinsic subunit ɛ and inhibitory ADP are responsible for the suppression of hydrolytic activity. These results suggest that the enzyme is needed for the synthesis of ATP, not for the maintenance of the PMF. For the development of new antimycobacterial drugs acting on ATP synthase, screening for ATP synthesis inhibitors, but not for ATP hydrolysis blockers, can be regarded as a promising strategy.

[Early functional treatment and full weight-bearing of surgically treated isolated ankle fractures in the elderly]

QUESTION

Fractures of the ankle joint belong to the most often occurring injuries. The aftercare in plaster lasts several weeks and is problematic especially in elderly patients.

METHODS

In a retrospective study patients over the age of 50 years who underwent surgical treatment of ankle fractures and early functional mobilization were examined in a follow-up. The range of motion, the circumferential measurements and the radiological course were examined by comparing preoperative and postoperative X-ray images after 13-24 months. The subjective results were collected using the Olerud-Molander score (OMS).

RESULTS

A total of 30 out of 42 patients who qualified for the follow-up were included in the study. The distribution of the gender was equal as was the right/left distribution and the mean age was 68 years. The magnitude of movement and comparison between the two sides showed no significant differences. The average score for subjective satisfaction was 90 in the OMS. The radiological results showed few changes and no deviations from the axis. No redislocations or implant fractures could be observed. Early functional full weight-bearing showed satisfactory preliminary results.

CONCLUSION

This treatment concept can be recommended because patient comfort is increased and the risk of immobilization is excluded.

[Proximal humeral fracture]

Fractures of the proximal humerus are very common in elderly people with an increasing incidence. Complex fracture-patterns are observed. For radiological examination x-rays in 2 planes are mandatory. Often an additive CT-scan can be useful for a better understanding of the whole fracture-character. Limits of accepted fracture displacement decrease and reconstructive surgery is induced more frequently. Advantageous are the functional after-treatment and the early reintegration to the activities of daily living after osteosyntheses. Locking nail- and platesystems are competing standard-implants, whereas plate osteosynthesis is preferred in higher-part-fractures. Non-reconstructable fractures should be treated with a primary head replacement, in the form of a reverse prosthesis in patients older than 75 years.

Arthroscopic treatment of multidirectional glenohumeral instability in young overhead athletes

Purpose:

This prospective case series evaluates the outcome, and the return to sports of young overhead athletes with a persistent, symptomatic multidirectional instability (MDI) with hyperlaxity type Gerber B5 treated with an arthroscopic anteroposteroinferior capsular plication and rotator interval closure.

Methods:

9 young overhead athletes (10 shoulders) with the rare diagnosis of MDI (Gerber B5) and an indication for operative treatment, after a failed physiotherapy program were physically examined 3, 6 and 12 months postoperatively by a physical examination, and got a final phone interview after median 39 months.

Results:

At the final follow-up all patients were satisfied; Rowe Score showed 7 “excellent” and “good” results; Constant Score was “excellent” and “good” in 6, and “fair” in 1 patient. 7/9 returned to their previous sports, 3/9 at a reduced level.

Conclusion:

Symptomatic MDI requires an individual indication for surgical treatment after a primary conservative treatment. The described arthroscopic technique stabilizes glenohumeral joint. A return to overhead sports is possible but often at a reduced level; returning to high-performance sports cannot be recommended because of the high risk of reinstability.

Two-stimuli manipulation of a biological motor

F1-ATPase is an enzyme acting as a rotary nano-motor. During catalysis subunits of this enzyme complex rotate relative to other parts of the enzyme. Here we demonstrate that the combination of two input stimuli causes stop of motor rotation. Application of either individual stimulus did not significantly influence motor motion. These findings may contribute to the development of logic gates using single biological motor molecules.

[Primary hemiarthroplasty in proximal humerus fractures]

The surgical treatment of complex proximal humerus fractures is still a great challenge. Not all fracture types can be successfully reconstructed. Indications for a primary joint replacement arise from critical fracture patterns and defined predictors of ischemia in the elderly (age >60 years). If good functional results are to be achieved a soft-tissue-preserving surgical technique, secure tuberosity attachment and accurate soft tissue balancing of the rotator cuff, correct restoration of height, retrotorsion and offset, and appropriate physiotherapy afterwards are essential. In multicentre studies in patients who had undergone primary hemoarthroplasty average Constant-Murlay Scores of 56.0-73.5 point were recorded. At follow-up, 79% of the patients reported only mild pain or none at all, and the ROM was acceptable (41.9% anteversion >90 degrees , 34.7% abduction >90 degrees ). Generally, subjective evaluations were much better than the objective results.The incidence of complications after humeral head replacement is still relatively high, whereas the 10-year survival rate of shoulder hemiarthroplasties has been found in a recent study to be 100%.

Diarylquinolines target subunit c of mycobacterial ATP synthase

The diarylquinoline R207910 (TMC207) is a promising candidate in clinical development for the treatment of tuberculosis. Though R207910-resistant mycobacteria bear mutations in ATP synthase, the compound's precise target is not known. Here we establish by genetic, biochemical and binding assays that the oligomeric subunit c (AtpE) of ATP synthase is the target of R207910. Thus targeting energy metabolism is a new, promising approach for antibacterial drug discovery.

Komplikationsmanagement nach winkelstabiler Plattenosteosynthese am proximalen Humerus

PURPOSE

In this prospective study, complications observed after angularly stable proximal humerus plate fixation (locking proximal humerus plate) were analysed by deriving specific therapies.

PATIENTS

Fifty patients (median age 65 years, range 25-84 years, 39 female, 11 male) with displaced proximal humerus fractures (seven single, 36 double, and seven triple fractures) were evaluated 3, 6, and 12 months after angularly stable plate fixation using a standard protocol.

RESULTS

Age- and gender-matched median constant scores 12 months postoperatively showed for the three fracture types 86, 87, and 55 points and complication rates of 14, 19, and 100%, respectively. There were seven primary and seven secondary implant displacements, five humeral head necroses, four osseous malalignments, two nonunions, two deep infections, and one heterotopic ossification. Nine reoperations were required in six patients: implant removal (n=3), reosteosynthesis (n=2), revision because of nonunion (n=2), and deep infection (n=2).

CONCLUSIONS

Differentiated analysis of complications and the development of specific prevention and therapeutic strategies considering surgical technique, implant, fracture morphology, and humeral head perfusion minimize the rate of complications observed after angularly stable locking proximal humerus plate fixation.

The V-ATPase from etiolated barley (Hordeum vulgare L.) shoots is activated by blue light and interacts with 14-3-3 proteins

The vacuolar H(+)-ATPase (V-ATPase) is a key enzyme that controls the electrochemical proton potential across endomembranes. Although evidence suggests that V-ATPase is important for photo-morphogenesis, little is known about short-term regulation of V-ATPase upon initiation of the photo-morphogenetic programme by exposure of dark-grown plants to light. In this study, etiolated coleoptiles were given a short blue light treatment and V-ATPase characteristics were determined. The effectiveness of the light treatment was assessed by means of fusicoccin binding to the plasma membrane; this increased 5-fold. The short light treatment also induced a 2-fold to 3-fold increase in the hydrolytic activity of V-ATPase. Members of the 14-3-3 protein family are involved in both blue light perception and the subsequent activation of the P-type ATPase. We provide evidence that 14-3-3 proteins specifically interact with the catalytic A-subunit of the V-ATPase. First, the isolated V1-part of the V-ATPase co-purifies with 14-3-3 on a gel filtration column. Secondly, in an overlay experiment, 14-3-3 interacts with a 68 kDa band that was identified as the V1 A-subunit by mass spectrometry. Thirdly, in 14-3-3 affinity chromatography, both A- and B-subunits of the catalytic moiety of the V-ATPase were identified by matrix-assisted laser desorption ionization tandem time of flight mass spectrometry (MALDI TOF/TOF MS) as 14-3-3-interacting proteins. It was shown that the A-subunit can be phosphorylated in vitro by a tonoplast-bound kinase, whose properties are affected by blue light. Taken together, the data show that besides the P- and F-type H(+)-ATPases, the V-type H(+)-ATPase also interacts with 14-3-3 proteins.

Die Candida-albicans-induzierte Spondylodiszitis der Halswirbelsäule bei einem polytraumatisierten Patienten

With the increasing occurrence of predisposing factors, invasive candidiasis is being diagnosed more frequently. Based on a review of only a few previous reported cases, we describe and discuss the unusual case of candidal cervical spondylodiscitis in a 36 year old man who had sustained a polytrauma, complicated through a Candida albicans pneumonia. The main symptom was disabling neck pain. Clinical, laboratory and radiological findings were unspecific. The definitive diagnosis was determined by MRI imaging and biopsy. The early diagnosis and surgical treatment with a sufficient debridement and stabilisation of the affected segment combined with a prolonged antifungal therapy lead to good results.

Welche Vorteile bietet die volare Plattenosteosynthese gegenüber der Kirschner-Drahtstabilisierung bei distalen Radiusextensionsfrakturen des alten Menschen?

PURPOSE

The purpose of this retrospective study was to compare the outcome of open reduction and internal fixation (ORIF) followed immediately by physiotherapy and of percutaneous K-wire-fixation and casting for unstable distal radius fractures in elderly patients, considering the results both in general, for all such fractures, and selectively for A3 and C2 fractures.

METHODS

Follow-up examinations were performed 26 (18-48) months after surgery in 43 patients (median age 67 (60-83) years) treated with K-wire fixation and 9 (5-17) months after surgery in 46 patients (median age 76 (60-90) years) treated with ORIF, and the outcome of each was recorded as Disabilities of the Arm, Shoulder and Hand (DASH), Gartland-Werley and Castaing scores; the radiological loss of correction was also assessed. Statistical analysis was performed first without reference to the specific type of fracture for the K-wire- and the total ORIF -groups, and then selectively for A3 and C2 -fractures only; in the second analysis the patients were divided into three groups: KD, ORIF with and ORIF without angular stability.

RESULTS

The Garland-Werley and Castaing scores do not indicate any significant difference between the procedures specified. According to the Garland-Werley score 37 patients (86%) treated by K-wire fixation and 39 (85%) treated by ORIF achieved "excellent" and "good" results; according to the Castaing score there were 33 (77%) "good" results after K-wire fixation and 34 (74%) good results after ORIF. The radiological loss of correction (K-wire fixation/ORIF) as measured by the radial inclination (median 2/2.5 degrees), the palmar tilt (median 3/5 degrees) and the radial shortening (median 1/1 degrees mm) do not differ significantly. Suboptimal radiological results do not always correlate with results that are only "fair" or "poor". The non-fracture-specific DASH score suggests a higher degree of patient satisfaction after K-wire fixation (7 [0-87] points) than after ORIF (17 [0-82] points), which is not confirmed by fracture-specific evaluation. There is a significantly earlier return to the "activities of daily living" (4 as against 8 weeks) after ORIF.

CONCLUSION

All the treatments compared are suitable for the treatment of A3 and C2 fractures. The important advantages of ORIF are the early functional physiotherapy without casting and without obligatory second surgery and the earlier return to "activities of daily living", which are all of decisive importance for older patients, who are the ones most frequently affected.