A CRISPR-Cas9 tool to explore the genetics of Bacillus subtilis phages

Here, we present pRH030, a new CRISPR-Cas9 tool for the genetic engineering of Bacillus phages and beyond. It is based on the Streptococcus pyogenes cas9 with its native constitutive promoter, tracrRNA, and a gRNA precursor. The constitutive expression of Cas9 was conducive to the inactivation of viral attackers and enhanced phage mutagenesis efficiency up to 100%. The gRNA precursor can be built up to an artificial CRISPR array with up to 5 spacers (target sequences) assembled from ordinary oligonucleotides and directly cloned into pRH030. Required time and resources remain comparable to a single gRNA cloning. These properties make pRH030 an attractive new system for the modification of Bacillus phages and qualify it for research beyond genetic construction.

Ultrafast domain wall dynamics in magnetic nanotubes and nanowires

The dynamic properties of magnetic domain walls in nanotubes and in cylindrical nanowires can be significantly different from the well known domain wall dynamics in thin films and in flat thin strips. The main differences are the occurrence of chiral symmetry breaking and, perhaps more importantly, the possibility to obtain magnetic domain walls that are stable against the usual Walker breakdown. This stability enables the magnetic field-driven propagation of the domain walls in nanotubes and nanocylinders at constant velocities which are significantly higher than the usual propagation speeds of the domain walls. Simulations predict that the ultrafast motion of magnetic domain walls at velocities in a range above 1000 m s^-1 can lead to the spontaneous excitation of spin waves in a process that is the magnetic analog of the Cherenkov effect. In the case of solid cylindrical wires, the domain wall can contain a micromagnetic point singularity. We discuss the current knowledge on the ultrafast dynamics of such Bloch points, which remains still largely unexplored.

Conjugative reporter system for the use in Bacillus licheniformis and closely related Bacilli

Bacillus wild-type strains are genetically difficult to manipulate, and thus, the options for rational strain investigation and design are limited. Here, we present a set of small conjugative shuttle vectors for the use in Bacillus licheniformis and related, genetically difficult accessible wild-type strains. The vector set comprises the modular general-purpose vector pV2 and its derivatives pV3SDlacZ and pV3lacZ. The pV3 vectors are designed for the investigation of transcriptional and translational activities of regulatory regions like promoters and ribosomal binding sites (RBS). The vector set has been tested for investigating gene regulation under aerobic and anaerobic conditions.

Disentangling the physical contributions to the electrical resistance in magnetic domain walls: a multiscale study

We analyze the origin of the electrical resistance arising in domain walls of perpendicularly magnetized materials by considering a superposition of anisotropic magnetoresistance and the resistance implied by the magnetization chirality. The domain wall profiles of L1(0)-FePd and L1(0)-FePt are determined by micromagnetic simulations based on which we perform first-principles calculations to quantify electron transport through the core and closure region of the walls. The wall resistance, being twice as high in L1(0)-FePd than in L1(0)-FePt, is found to be clearly dominated in both cases by a high gradient of magnetization rotation, which agrees well with experimental observations.

Comparison of two different locking plates for two-, three- and four-part proximal humeral fractures--results of an international multicentre study

PURPOSE

The aim of this study was to compare the functional outcome, quality of restoration, and complication rate after open reduction and internal fixation (ORIF) of displaced or unstable 2-, 3- and 4-part humeral fractures using two different locking plates.

METHODS

The data used in this analysis was prospectively collected in two large multicentre studies in 15 European Level 1 trauma centres. A total of 318 patients with proximal humeral fractures were treated with ORIF using either the locking proximal humerus plate (LPHP) or proximal humeral internal locking system (PHILOS). Outcome measurements included Constant and Neer scores, evaluation of local pain at the fracture site and complications, and radiographic assessment at one year.

RESULTS

At one year, the mean Constant scores (relative to the contralateral shoulder) improved significantly for both groups and were above 80% for 2-, 3-, and 4-part fractures. A significantly shorter surgical time, less pain at the fracture site, and better functional outcome was achieved by PHILOS-treated patients with 2-part fractures throughout the one-year follow-up month and with 3-part fractures at three months (p < 0.05). There was no difference between the treatment outcomes for 4-part fractures, and no difference in the complication rates (p > 0.05).

CONCLUSIONS

PHILOS and LPHP can be considered as useful implants for ORIF of displaced and unstable proximal humeral fractures. There was a slight advantage of the PHILOS system with regard to operative time and functional outcome, especially for the treatment of 2- and 3-part fractures.

Ultrafast nanomagnetic toggle switching of vortex cores

We present an ultrafast route for a controlled, toggle switching of magnetic vortex cores with ultrashort unipolar magnetic field pulses. The switching process is found to be largely insensitive to extrinsic parameters, like sample size and shape, and it is faster than any field-driven magnetization reversal process previously known from micromagnetic theory. Micromagnetic simulations demonstrate that the vortex core reversal is mediated by a rapid sequence of vortex-antivortex pair creation and annihilation subprocesses. Specific combinations of field-pulse strength and duration are required to obtain a controlled vortex core reversal. The operational range of this reversal mechanism is summarized in a switching diagram for a 200 nm Permalloy disk.

Magnetic vortex core reversal by excitation with short bursts of an alternating field

The vortex state, characterized by a curling magnetization, is one of the equilibrium configurations of soft magnetic materials and occurs in thin ferromagnetic square and disk-shaped elements of micrometre size and below. The interplay between the magnetostatic and the exchange energy favours an in-plane, closed flux domain structure. This curling magnetization turns out of the plane at the centre of the vortex structure, in an area with a radius of about 10 nanometres--the vortex core. The vortex state has a specific excitation mode: the in-plane gyration of the vortex structure about its equilibrium position. The sense of gyration is determined by the vortex core polarization. Here we report on the controlled manipulation of the vortex core polarization by excitation with small bursts of an alternating magnetic field. The vortex motion was imaged by time-resolved scanning transmission X-ray microscopy. We demonstrate that the sense of gyration of the vortex structure can be reversed by applying short bursts of the sinusoidal excitation field with amplitude of about 1.5 mT. This reversal unambiguously indicates a switching of the out-of-plane core polarization. The observed switching mechanism, which can be understood in the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application in data storage.

Peritonitis in childhood: clinical relevance of cytokines in the peritoneal exudate

BACKGROUND

The aim of the study was to assess pro-inflammatory cytokine (tumor necrosis factor alpha [TNF-alpha], interleukin 6 [IL-6]) and anti-inflammatory cytokine (interleukin 10 [IL-10]) responses in children with peritonitis secondary to hollow viscus perforation, and to evaluate the influence of peritoneal microbial status on cytokine expression and morbidity.

METHODS

The peritoneal fluid of 13 children with perforated appendicitis was examined with qualitative analysis of bacteria, and measurement of cytokine levels, which were compared to cytokine plasma levels, over a five-day period following operation.

RESULTS

All fluid specimens showed permanently elevated levels of TNF-alpha and IL-10. IL-6 tended to decrease to normal levels by the 5th postoperative day. Peritoneal exudate levels of TNF-alpha and IL-10 were more than 100 - 1000 times greater than those in plasma. The most common bacterial species isolated in the peritoneal fluid was Escherichia coli. Despite persisting high cytokine concentrations and bacterial load of the peritoneal cavity for 5 days postoperatively, the children recovered uneventfully and the systemic signs of infection disappeared rapidly.

CONCLUSION

Neither the bacterial nor the pro-inflammatory cytokine load of the peritoneal cavity proved to be associated with the clinical course. We hypothesize that in peritonitis in childhood a significant and clinically relevant cytokine-mediated inflammatory response is compartmentalized in the peritoneal cavity. Therefore adjuvant surgical measures in addition to appendectomy and intraoperative debridement seem not to be necessary, at least for peritonitis due to perforated appendicitis in children.

Specificity patterns indicate that auxin exporters and receptors are the same proteins

A study of transport and action of synthetic auxin analogues can help to identify transporters and receptors of this plant hormone. Both aspects--transportability and action on growth--were tested with 2-naphthoxyacetic acid (2-NOA) and compared across several plant species. 2-NOA stimulates elongation effectively at low concentrations in petioles of the gymnosperm Ginkgo biloba L., in hypocotyls or internodes of the dicot legumes, mung bean (Vigna mungo L.) and pea (Pisum sativum L.), in cotyledons of onion (Allium cepa L.) and in leaf bases of chive (Allium schoenoprasum L.), the latter two of the monocot order Asparagales. In contrast, elongation of coleoptile segments of maize (Zea mays L.) is poorly responsive to 2-NOA. Significant auxin-like transport of 2-NOA was observed in segments of mung bean hypocotyls, pea internodes, and chive leaf bases, but not in segments of the grass coleoptiles. Thus, for the two assays, elongation and polar transportability, the same difference in ligand specificity was observed between the grass and all other species assayed. This finding supports the hypothesis that a common protein mediates auxin efflux as well as auxin action on elongation.

Predictors of humeral head ischemia after intracapsular fracture of the proximal humerus

The purpose of this study was to evaluate predictors of fracture-induced humeral head ischemia. Between February 1998 and December 2001, 100 intracapsular fractures of the proximal humerus, treated by open surgery, were included in a prospective surgical evaluation protocol (mean age, 60 years; minimum, 21 years; maximum, 88 years; 45 men; 57 right shoulders). Fracture morphology was assessed following a structured questionnaire and based on radiographic and intraoperative findings. Perfusion was assessed intraoperatively by observation of backflow after a borehole was drilled into the central part of the head in all shoulders and by intraosseous laser Doppler flowmetry in 46. Good predictors of ischemia were the length of the metaphyseal head extension (accuracy, 0.84 for calcar segments <8 mm), the integrity of the medial hinge (accuracy, 0.79 for disrupted hinge), and the basic fracture pattern (accuracy, 0.7 for combined types 2, 9, 10, 11, and 12). Moderate and poor predictors of ischemia were fractures consisting of four fragments (accuracy, 0.67), angular displacement of the head (accuracy, 0.62 for angulations over 45 degrees ), the amount of displacement of the tuberosities (accuracy, 0.61 for displacement over 10 mm), glenohumeral dislocation (accuracy, 0.49), head-split components (accuracy, 0.49), and fractures consisting of three fragments (accuracy, 0.38). When the above criteria (anatomic neck, short calcar, disrupted hinge) were combined, positive predictive values of up to 97% could be obtained. The most relevant predictors of ischemia were the length of the dorsomedial metaphyseal extension, the integrity of the medial hinge, and the basic fracture type determined with the binary description system.

Direct observation of the single-domain limit of Fe nanomagnets by spin-polarized scanning tunneling spectroscopy

We have investigated the magnetic structure of self-organized Fe islands on W(001) by means of spin-polarized scanning tunneling spectroscopy (Sp-STS). Single-domain, simple vortex, and distorted vortex states have been observed. The high resolution magnetic images were used to experimentally determine the single-domain limit. The experimental structures were compared with results of micromagnetic calculations confirming the ground state nature of the experimental configurations. The single-domain limit directly observed with Sp-STS is consistent with theoretical predictions.

Surgical landmarks to determine humeral head retrotorsion for hemiarthroplasty in fractures

Malrotation has been suggested as a cause of failure of hemiarthroplasty of the proximal humerus. Placing a shoulder prosthesis in relationship to the bicipital groove might reproduce individual anatomy more reliably than using a standardized retrotorsion. The purpose of this study was to determine criteria for accurate adjustment of retrotorsion even when the proximal bicipital groove is destroyed, as is the case in fractures. The distance of the humeral head equatorial plane to the center of the bicipital groove was measured by high-resolution computed tomography at 4 levels (proximal and distal with 2 intermediate levels). The distal distance was considered to correspond to available references in fracture cases. The mean proximal distance was 8.0 mm (10th percentile, 6.2 mm; 90th percentile, 9.8 mm), and the mean distal distance was 8.5 mm (10th percentile, 7.1 mm; 90th percentile, 9.9 mm). As to the clinical relevance, there was no statistically significant difference between distances. For practical purposes in fracture indications, it is adequate to adjust the retrotorsion of the prosthetic component to the distal bicipital groove.

Biomechanical and biological considerations relating to the clinical use of the Point Contact-Fixator--evaluation of the device handling test in the treatment of diaphyseal fractures of the radius and/or ulna

The Point Contact-Fixator (PC-Fix) was designed as part of the developmental evolution of more biological devices for internal fixations. It is a device characterized by minimal contact to the underlying periosteum and bone, hereby minimizing potential damage to perfusion. A multicentre handling test was conducted in 1993 and 1994 in six hospitals to assess its performance. A total of 83 fractured forearm bones (34 radii and 49 ulnae) in 52 patients were stabilized with a PC-Fix. The mean age of the patients was 37 years. There were 24 AO type A, 24 type B and 5 type C fractures. Nine fractures were open. Mean follow-up was 15.6 months; follow-up was 100%. All 21 surgeons involved considered the use of the PC-Fix self-explanatory and relatively easy. Handling difficulties were mainly related to insertion of the monocortical screws. In particular, the precision required for insertion, the inability to incline the screw and the inability to pull the plate to the bone using the screw were considered hard to deal with. Stripping of the hexagonal slot was a problem at removal of the implant, possibly related to overtightening of the screws at insertion. In 76 of 83 bones (49 of 53 forearms), the fractures united without additional surgery. The healing pattern typically showed early callus formation bridging the fracture, followed by progressive mineralization of the central radiolucent line. Complications included one infection, one late displacement and four delayed unions, all requiring revision surgery. In 8 forearms, plate removal was performed after a mean of 10.3 months. Two refractures occurred after removal of the implant 6 and 7 months postoperatively. In conclusion, the practical handling of the new implant was straightforward and easily learnt. The treatment failures observed were related to technical and strategic errors. We consider that, when using devices with a locking compression principle, a minimum number of three screws should be placed on each side of the fracture, that interfragmentary compression of simple fractures is desirable in order to increase stability and that, contrary to in vivo animal studies, early plate removal is not indicated. The trend in fracture fixation is to improve the biomechanical and biological properties of operating technique and the devices used. The PC-Fix has proven a useful step in the right direction in this evolutionary process.

[Open arthrolysis in preserved joint surface geometry]

This review article discusses the operative treatment options for release of essentially extracartilaginous contractures of the elbow (referred to as extrinsic contractures). Indications, preoperative work-up, specific operative strategy and techniques, rehabilitation, possible complications, and results are discussed and compared. Special reference is made to the technique of sequential surgical release based on the transhumeral approach. This technique makes it possible to optimize the articular offset while preserving the static and dynamic stabilizers of the joint. Treatment of contractures of the elbow remains dangerous and delicate. It deserves experienced surgical handling in order to avoid complications. Thus, it remains to be hoped that qualified management will help to improve the relatively mediocre functional results.

Cotton-induced pseudotumor of the femur

Twenty-five years prior to presentation a 41-year-old man had a femoral fracture stabilized with a 4.5 mm AO/ASIF steel plate. The femur healed uneventfully and the patient was asymptomatic for the following 20 years. He then noticed a slow-growing swelling of the left thigh associated with a degree of weakness. Radiographs of the femur 25 years after fracture stabilization showed a massive expansive osteolytic process surrounded by a rim of bone. Magnetic resonance imaging (MRI) confirmed the presence of a large tumor. Since malignancy could not be excluded the patient underwent incisional biopsy. The histologic findings were nonspecific. Because of persistent symptoms the lesion was marginally excised. Intraoperatively a folded cotton sponge was found adjacent to the femur. Histopathologic investigation confirmed a foreign body reaction probably related to the retained cotton sponge. Reactive, foreign-body-induced change may mimic bone and or soft tissue malignancies.

[Glenohumeral joint. Anatomical aspects and implications for prosthesis design]

Knowledge of normal anatomy and kinematics of the glenohumeral joint as well as analysis of the pathoanatomic changes that occur during the course of the disease is the condition for successful patient management. This review article critically discusses the most relevant geometrical variables. Systematically, normal anatomy, pathologic anatomy, and the implications for prosthetic design and implantation are presented. The most important aspects concerning the size and shape of the glenoid, the inclination of the articular surface in the horizontal and frontal planes, as well as the geometry of the scapular neck are discussed. The accumulated knowledge is of immediate practical use and might stimulate researchers and manufacturers to develop more adequate glenoid components.

Auxin-induced elongation of short maize coleoptile segments is supported by 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one

Endogenous extractable factors associated with auxin action in plant tissues were investigated, especially their effects on elongation of 1-mm coleoptile segments of maize (Zea mays L.), in the presence of saturating 10 microM indole-3-acetic acid (IAA). The relative growth response, to auxin alone, was much smaller in segments shorter than 2-3 mm compared to 10-mm segments. Fusicoccin-induced elongation, however, was less affected by shortening the segments. A reduced auxin response may result from the depletion through cut surfaces of a substance required for IAA-mediated growth. Sucrose, phenolics like flavonoids, and vitamins were ruled out as the causal factors. A partially purified methanol extract of maize coleoptiles supported longterm, auxin-controlled elongation. The active material was also found among substances bleeding from scrubbed maize coleoptiles. The active factor from maize was further purified by HPLC and characterised by the UV spectrum and its pH shift. This factor was identified as 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) by mass spectroscopy. Activity tests confirmed that pure DIMBOA from other sources sustained auxin-induced elongation of short maize coleoptile segments. However, DIMBOA only partially restored the activity lost from short segments. This indicates that an additional factor, other than DIMBOA, is required. Extracts from Avena or Cucurbita did not contain the factor DIMBOA; it was active on maize elongation, but not on Avena coleoptiles or Cucurbita hypocotyls. This narrow specificity and the lack of DIMBOA action in short-term tests with maize indicate that DIMBOA is not the general auxin cofactor but may specifically "spare" the co-auxin in maize.

[Shoulder injury in general practice]

Injuries to the shoulder and shoulder-girdle represent a demanding diagnostic and therapeutic challenge. The complex and minimally constrained anatomic construction of the joints is critical. Although a large majority of the injuries are relatively trivial it is essential to recognize critical lesions that deserve intensive investigation and appropriate treatment. In view of the severity of the consequences of particular injury patterns this article focuses on fractures of the proximal humerus, gleno-humeral dislocations and on acute ruptures of the rotator cuff. In particular, attention will be drawn on fractures with avascular head fragment, primarily undisplaced fractures of the anatomic neck, unrecognized posterior dislocation and on under diagnosed acute ruptures of the rotator cuff. The key issue for a secure diagnosis are a precise physical examination and an adequate conventional radiologic investigation. Both aspects are discussed with practically relevant suggestions.

[Diagnosis of rotator cuff rupture: correlation of clinical findings and magnetic resonance tomography with intraoperative findings]

The diagnosis of rotator cuff tears may be based on clinical examination and MRI. The aim of this study was to define the relative value of these methods. Clinical and MRI diagnoses of 88 shoulders were compared with the intraoperative findings. The correct diagnosis of a posterosuperior rotator cuff rupture was made in 79% of the cases by clinical examination and in 91% of the cases by MRI. For the subscapularis tendon clinical examination corresponded to the intraoperative findings in 73% of the cases versus 59% for MRI. MRI was superior to clinical examination in diagnosing a posterosuperior rotator cuff rupture. For the evaluation of ruptures of the subscapularis tendon, clinical examination was more reliable than MRI. Diagnosis of rotator cuff rupture can most often be obtained by a simple physical examination.

[The frozen shoulder]

Painful stiffness of the shoulder is an ill-defined clinical entity that is difficult to assess and delicate to treat. The nomenclature used is broad and includes terms such as frozen shoulder, adhesive capsulitis, focal algodystrophy, stiff shoulder, contracted shoulder, and others. Apart from its idiopathic form, the disease can be initiated by trauma, infection, tumour, radiation, systemic and local metabolic disturbances. Pathoanatomically, the common denominator is an inflammatory vascular proliferation followed by thickening, scarring, and retraction of the joint capsule. The inflammatory process often starts at the rotator interval and may extend to the subacromial space. Clinical diagnosis is based on history and physical examination. Generally the onset of pain precedes the perception of a reduced range of motion by weeks or months. In early stages of the disease, the inflammatory type of pain dominates, i.e., the patient's main complaint ist pain at night. In the later stage, range of motion gradually decreases. Patients do not often complain about reduced motion, probably because of its slow onset. Treatment options are a combination of mobilisation exercises with intra-articular steroids, hydraulic distension of the joint capsule, manipulation under anaesthesia, arthroscopic and/or open arthrolysis. The appropriate choice of protocol is just as important as its correct timing. In the inflammatory phase, aggressive treatment protocols are probably contraindicated. Complications of invasive protocols are rare but deleterious and therefore have to be taken into consideration. New anti-anglogenetic agents may enhance functional results and shorten the rehabilitation phase.

Free nerve endings in the ligamentum capitis femoris

We report the presence of free nerve endings (FNE) in the ligamentum capitis femoris (LCF). Qualitative and quantitative measurements on the incidence of FNE, as assessed by immuno-histochemistry for the S-100 protein, were obtained from 18 patients undergoing hip surgery. We found FNE in all LCF, with no association to age. The presence of FNE in the LCF suggests a role in noci-/proprioception of the hip.

Treatment of tibial plateau fractures with small fragment internal fixation: a preliminary report

OBJECTIVE

To evaluate the use of small fragment implants for fractures of the proximal tibia.

DESIGN

Retrospective.

SETTING

Level I trauma center.

PATIENTS/PARTICIPANTS

Seventeen patients with AO Classification Type B and C fractures of the proximal tibia. Two patients were lost to follow-up.

INTERVENTION

After atraumatic dissection and open reduction, fracture stabilization was accomplished with the use of the AO/ASIF small T-plate (3.5-millimeter system). In two patients a medial uniplanar external fixator was applied as additional fixation. In six patients a cancellous autograft was performed.

MAIN OUTCOME MEASUREMENTS

At an average follow-up of forty-two months (range, 24 to 75 months), all patients were evaluated radiographically and functionally. The incidence of local complications was specifically recorded.

RESULTS

Postoperatively, the radiographs showed 86.7 percent anatomic or near anatomic reduction with respect to the articular joint surface. In three separate patients condylar widening, condylar narrowing or varus deformity was evident. In one patient, a minimal secondary displacement of less than two millimeters was observed before bony healing. All fractures healed within twelve weeks. At the latest follow-up, there were 53.3 percent excellent, 33.3 percent good, and 13.3 percent fair results. There were no infection or soft tissue complications.

CONCLUSIONS

The use of small fragment implants combined with atraumatic soft tissue dissection potentially offers good results for the treatment of fractures of the proximal tibia. These initial results suggest that this technique may have the advantage of anatomic reduction while comparing favorably with less invasive methods regarding radiologic and functional outcome as well as incidence of complications.

The evolution of indirect reduction techniques for the treatment of fractures

During the last decade, classic AO/ASIF techniques for internal fixation shifted from direct reduction and rigid fixation to biologic internal fixation using indirect reduction techniques. Biologic internal fixation is characterized by the preservation of bone and soft tissue vascularity and relative rather than absolute mechanical stability. Reduction is achieved by using soft tissue traction while obtaining axial and rotational alignment and the correct length. Stabilization is performed when possible by compression plating for load sharing or by bridge plating in comminuted fractures. Advancements of these techniques and the development of newer implants that minimize vascular damage have contributed to the development of biologic internal fixation. By using indirect reduction, by using longer plates to improve the mechanical leverage, and by applying fewer screws to avoid unnecessary damage to the bone, fracture union rates were high. There also was a decreased need for supplemental bone grafting. All of these factors provided stable fixation and allowed early motion.

Total elbow replacement with the GSB III prosthesis

Fourteen consecutive elbows have been treated for rheumatoid arthritis (9 elbows) and for post-traumatic osteoarthrosis (5 elbows) by total elbow replacement with the GSB III implant. The elbows were reviewed retrospectively after a mean follow-up of 6 years (2 to 9 years). Ten of 14 elbows had a functioning GSB III implant at follow-up; 7 of them were rated satisfactory and 3 unsatisfactory with the Mayo elbow performance score. In 5 of these 10 cases, the patients had significant pain relief with no or only mild pain at follow-up, whereas 5 had moderate to severe pain. With a functioning implant the range of motion averaged 140 degrees of flexion, 19 degrees of lack of extension, 65 degrees of pronation, and 84 degrees of supination. Six (43%) elbows had major complications requiring 1 to 8 additional operations. Aseptic loosening requiring revision occurred in 4 (29%) elbows. Two of them were treated by a resection arthroplasty, and 2 were revised with another hinged semiconstrained device. Three further elbows had radiolucent lines involving more than 50% of the cement-bone interface of either the humeral or the ulnar component. However, in 8 elbows the cementing technique was considered marginal or inadequate. Poor cementing (marginal or inadequate) was associated with loosening (P = .008). The GSB III total elbow prosthesis can restore function and reduce pain. The rate of aseptic loosening in this series was higher than previously reported. Based on this observation, we conclude that the GSB III implant seems to be sensitive to the insertion technique and does not tolerate suboptimal cementing.

Unexpected resection of soft-tissue sarcoma. More mutilating surgery, higher local recurrence rates, and obscure prognosis as consequences of improper surgery

Sixteen referred patients were reviewed after excision of an unexpected soft-tissue sarcoma of the extremities. Eight tumors were located in the muscle deep to the fascia, and 8 lesions exceeded the size of 5 cm. The lack of awareness by the primary physician towards the possibility of a malignant lesion was striking, although 11 of 16 tumors presented as a newly formed mass. No imaging studies were done in 11 patients. Fine needle biopsy was unsuccessfully performed in 3 patients. Eleven lesions (63%) were high-grade. Resection margins were intralesional in 12 (75%) and marginal in 4 (25%) patients. Surgical oncologic rules were disregarded in 7 cases, including opening of probably uninvolved joints. Postoperative magnetic resonance imaging (MRI) scans showed a poor negative predictive value for residual tumor. Repeated resection, including three amputations, revealed residual tumor in 10 patients (63%). Four patients received adjuvant local radiation, with additional chemotherapy in 2 of them. At an average follow-up of 4.5 years (range 15-149 months), 4 patients (25%) had developed distant metastases with a local recurrence in 3 (19%). There was one tumor-related death (6%). Physicians' alertness towards the possible malignancy of an enlarging mass cannot be overemphasized. Evaluation by adequate imaging techniques, biopsy, and definitive resection and reconstruction should be performed by an oncologically trained orthopaedic surgeon. Inadequate primary excision leads to a high local recurrence rate and more mutilating surgery and obscures the long-term prognosis.

The medial malleolar network: a constant vascular base of the distally based saphenous neurocutaneous island flap

Based on 30 fresh cadaver dissections a detailed anatomic study of the medial malleolar network is presented with particular attention to the anastomoses between the latter and the vascular axis that follows the saphenous nerve. The medial malleolar network is formed by the anterior medial malleolar artery, branches from the medial tarsal arteries, the posterior medial malleolar artery and branches from the medial plantar artery. A distinct anterior medial malleolar artery and posterior medial malleolar artery could be identified in 80 and 20%, respectively, as well as constant additional small branches arising from the anterior tibial or posterior tibial artery. A constant anastomosis was found between the arcade formed by the medial tarsal arteries and the medial plantar a. in 60%, and the medial branch of the medial plantar artery in 40%, respectively. This anastomosis always gave rise to branches to the medial malleolar network. In the perimalleolar area and with regard to the great saphenous v. a larger anterior and a smaller posterior branch of the saphenous nerve was found in 100 and 90%, respectively. In all dissections, for both branches of the saphenous nerve two to four small, but distinct anastomoses between the medial malleolar network and the perineural vascular axis were identified. These constant anastomoses represent a new and reliable vascular base for the distally-based saphenous neurocutaneous island flap. Thus, the pivotal point of the flap can be chosen in the area of the medial malleolus without respecting the most distal septocutaneous anastomosis between the perineural vascular axis and the posterior tibial artery. Additionally, an illustrative clinical case is presented.

On the timing of soft-tissue reconstruction for open fractures of the lower leg

The timing of soft-tissue reconstruction for severe open fractures of the lower leg is considered crucial to the later outcome, and yet pertinent publications are few. The purpose of this study was to add some based on evidence arguments for the choice of the most adequate timing in the management of these injuries. Twenty-nine consecutive open fractures of the tibia, including 24 grade 3B and 5 grade 3C fractures, were treated using a protocol of immediate debridement, early definitive skeletal stabilisation and early soft-tissue reconstruction. Fifteen lower legs were reconstructed after a mean delay of 4.4 days (range 1-9 days), while 14 lower legs were reconstructed immediately, i.e. as an emergency procedure on the day of admission. Both groups were comparable for sex, age, type of trauma, associated general injuries, type of fracture, associated arterial lesion, associated tendon rupture, type of soft-tissue reconstruction and duration of follow-up. All patients were reviewed at a mean follow-up of 47 months (range 15-89 months). In the delayed reconstruction group the time to full, unprotected weight-bearing (P = 0.0021), the time to definitive union (P = 0.0049), the number of reoperations (P = 0.0001) and the infection rate (P = 0.0374) were significantly higher. The data suggest that immediate reconstruction is, the general condition of the patient permitting, the timing of choice for soft-tissue coverage.

Glial cell line-derived neurotrophic factor rescues target-deprived sympathetic spinal cord neurons but requires transforming growth factor-beta as cofactor in vivo

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor for several populations of CNS and peripheral neurons. Synthesis and storage of GDNF by the neuron-like adrenal medullary cells suggest roles in adrenal functions and/or in the maintenance of spinal cord neurons that innervate the adrenal medulla. We show that unilateral adrenomedullectomy causes degeneration of all sympathetic preganglionic neurons within the intermediolateral column (IML) of spinal cord segments T7-T10 that project to the adrenal medulla. In situ hybridization revealed that IML neurons express the glycosylphosphatidylinositol-linked alpha receptor 1 and c-Ret receptors, which are essential for GDNF signaling. IML neurons also display immunoreactivity for transforming growth factor-beta (TGF-beta) receptor II. Administration of GDNF (recombinant human, 1 microg) in Gelfoam implanted into the medullectomized adrenal gland rescued all Fluoro-Gold-labeled preganglionic neurons projecting to the adrenal medulla after four weeks. Cytochrome c applied as a control protein was not effective. The protective effect of GDNF was prevented by co-administration to the Gelfoam of neutralizing antibodies recognizing all three TGF-beta isoforms but not GDNF. This suggests that the presence of endogenous TGF-beta was essential for permitting a neurotrophic effect of GDNF. Our data indicate that GDNF has a capacity to protect a population of autonomic spinal cord neurons from target-deprived cell death. Furthermore, our results demonstrate for the first time that the previously reported requirement of TGF-beta for permitting trophic actions of GDNF in vitro (Kreiglstein et al., 1998) also applies to the in vivo situation.

Transacromial approach to obtain fusion of unstable os acromiale

The purpose of this study was to identify possible causes for the low union rate for surgically stabilized os acromiale. Between February 1990 and November 1995, fusion of an os acromiale was attempted in 15 shoulders in 12 patients at our institution. All patients were men. The mean age was 54 years (range 37 to 63 years). All shoulders had an os mesoacromiale considered too large for simple resection. An associated lesion of the rotator cuff ranging from partial-to full-thickness tear was present in all patients. Eleven had an unfused acromial epiphysis in both shoulders. Two different surgical approaches were used. Seven shoulders were approached through an anterior deltoid-off approach, thus potentially devascularizing the os acromiale. Eight shoulders were approached transacromially, preserving the deltoid origin and hence the terminal branches of the thoracoacromial artery. The technique of internal fixation (tension band wiring) was the same for both groups. The mean follow-up was 44 months (range 13 to 72 months). Union, as demonstrated by axial radiographic views, occurred in 3 out of 7 cases with a devascularized os acromiale and in 7 out of 8 shoulders with a perfused os acromiale (P = .017), respectively. Patients with a united os acromiale had a significantly better functional outcome as measured by the Constant score (P = .0169). In conclusion, aiming at a stable fusion of a sizable and hypermobile os acromiale is probably desirable because it enhances the overall functional result. Obtaining consolidation was possible when the vascularity of the acromial epiphysis was respected.

Decortication and plate osteosynthesis for nonunion of the clavicle

Between 1968 and 1995, 37 patients with ununited fractures of the clavicle were treated by decortication and plate osteosynthesis. Thirty-two (86%) were failures of union of fractures of the middle third. Thirty-four (92%) patients had post-traumatic nonunion or delayed union. Sixteen (43%) patients had undergone primary operative treatment. Autogenous cancellous bone graft was used in 24 (65%) patients with atrophic nonunion. Nine tricortical, iliac crest, intercalary grafts were used for segmental bone loss equal to or greater than 15 mm. At the end of treatment, union had been achieved in 35 (95%) cases. At a mean follow-up of 8.6 years (range 13 months to 17 years), 32 (86%) patients had no symptoms and had a full range of motion of the shoulder. Decortication with plate osteosynthesis is a reliable, durable technique for the management of symptomatic, ununited fractures of the clavicle.

TrkB and neurotrophin-4 are important for development and maintenance of sympathetic preganglionic neurons innervating the adrenal medulla

The adrenal medulla receives its major presynaptic input from sympathetic preganglionic neurons that are located in the intermediolateral (IML) column of the thoracic spinal cord. The neurotrophic factor concept would predict that these IML neurons receive trophic support from chromaffin cells in the adrenal medulla. We show here that adrenal chromaffin cells in the adult rat store neurotrophin (NT)-4, but do not synthesize or store detectable levels of BDNF or NT-3, respectively. Preganglionic neurons to the adrenal medulla identified by retrograde tracing with fast blue or Fluoro-Gold (FG) express TrkB mRNA. After unilateral destruction of the adrenal medulla, 24% of IML neurons, i.e., all neurons that are preganglionic to the adrenal medulla in spinal cord segments T7-T10, disappear. Administration of NT-4 in gelfoams (6 microgram) implanted into the medullectomized adrenal gland rescued all preganglionic neurons as evidenced by their presence after 4 weeks. NT-3 and cytochrome C were not effective. The action of NT-4 is accompanied by massive sprouting of axons in the vicinity of the NT-4 source as monitored by staining for acetylcholinesterase and synaptophysin immunoreactivity, suggesting that NT-4 may enlarge the terminal field of preganglionic nerves and enhance their access to trophic factors. Analysis of TrkB-deficient mice revealed degenerative changes in axon terminals on chromaffin cells. Furthermore, numbers of FG-labeled IML neurons in spinal cord segments T7-T10 of NT-4-deficient adult mice were significantly reduced. These data are consistent with the notion that NT-4 from chromaffin cells operates through TrkB receptors to regulate development and maintenance of the preganglionic innervation of the adrenal medulla.

[Management of IIIB open tibial fractures by early osteosynthesis and local muscle flap]

From 1986 to 1994 18 patients with 19 IIIB open tibial fractures were treated following similar therapeutic management. This included early and radical primary debridement, early and wherever possible immediate internal fixation of the bone and coverage with a local muscle flap (hemisoleus or gastrocnemius). At the time of follow-up all fractures had consolidated clinically as well as radiographically. The mean time to bony union was 7 months (3-20). Twelve patients did not have any severe pain and were able to walk for more than 4 km. The time to return to work averaged 8 months. In 2 cases a permanent disability of 50% was established. Fourteen of 18 patients were satisfied with the function of the leg. On the other hand, 9 didn't like the aesthetic appearance and were inhibited because of it. The following complications occurred within a period of 2 years: non-union (3), flap necrosis (2), osteomyelitis (2), delayed union (4). The mean number of reoperations was 3 (0-8). In no case did an amputation have to be performed.

[Missed compartment syndrome after anterior cruciate ligament-plasty following continuous peridural anesthesia]

In this article we report a case of an early postoperative compartment syndrome of the anterior tibial compartment with complete sensomotoric palsy of the peroneal nerve after arthroscopic-assisted replacement of the anterior cruciate ligament (ACL) of the knee. The tourniquet pressure was 360 mm Hg and operation time was 1.75 h. After the operation the leg was bandaged to avoid swelling of the leg and as antithrombotic prophylaxis. Analgesic therapy was by continuous epidural bupivacaine infusion. Increasing pain of the lower leg was suppressed by additional analgesia. Due to persistent pain despite regular analgesia, the patient was sent to a main hospital on the 3rd postoperative day, where an extremely painful and swollen anterior tibial compartment with intracompartmental pressure of over 100 mm Hg was found. The compartment was released immediately. Despite the appearance of severe muscle damage, no extensive débridement was done. At the second examination, at 48 h, there was minimal perfusion of the muscles without contraction and islands of ischemic necrosis. Clinically, there was complete palsy of the dorsiflexors of the foot. The case shows the danger of a compartment syndrome when tourniquet of the limb, arthroscopy and a firm bandage are combined. Continuous epidural analgesia masks the classic symptoms of compartment syndrome.

Exercise-induced compartment syndrome in the flexor-pronator muscle group. A case report and pressure measurements in volunteers

Compartment syndrome is caused by an increase in intracompartmental pressure above the capillary level, preventing capillary flow. The acute onset of symptoms occurs after events such as fracture, soft tissue trauma, and revascularization and usually necessitates prompt fasciotomy to avoid loss of function or even necrosis of the enclosed muscle. Compartment syndromes in athletes are of a recurrent nature and are usually referred to as chronic. Nonoperative treatment is often successful. Although compartment syndromes can occur in several anatomic regions, the most commonly seen in athletes involve the leg. Chronic compartment syndromes of the upper extremity are rare, and only a few cases have been reported in the literature. The intracompartmental pressures causing chronic symptoms in these cases ranged between 22 mm Hg at rest and 40 mm Hg after 30 minutes of exercise. Under maximal contraction, a pressure of 58 mm Hg has been recorded. The object of this paper is to report a case of a tennis player where much higher flexor-pronator muscle intracompartmental pressures than those noted above were recorded. We compared the intracompartmental pressure data of this patient with intracompartmental pressures measured in six symptom-free volunteers.

The deltoid extension lag sign for diagnosis and grading of axillary nerve palsy

The deltoid extension lag sign has been developed to avoid the pitfalls confounding the diagnosis of an axillary nerve lesion. The physician elevates the arm into a position of near full extension. The patient is asked to attempt active maintenance of this position. If the deltoid is weak, the arm will drop. In five patients with traumatic axillary nerve palsy after anterior dislocation of the shoulder, the deltoid extension lag sign was used to evaluate the functional status of the deltoid muscle. The magnitude of the angular drop, or lag, of the arm was a precise indicator of the functional status and recovery of the deltoid. The sign proved to be objective and reproducible, allowing confident assessment of deltoid function and when repeated over time allowed precise follow-up of deltoid recovery.

[Indications and results of shoulder prosthetics in complex proximal humerus fractures]

Complex fractures of the proximal humerus are uncommon injuries and a therapeutic challenge to the orthopaedic surgeon. Successful treatment requires proper evaluation of the patient and analysis of standardized high-quality radiographs. The trauma series of radiographs (including true anteroposterior and lateral views in the scapular plane, and axillary view) is essential for accurate fracture assessment. Generally, joint-preserving reconstructive techniques are emphasized, aiming at restoration of the anatomy of the proximal humerus. In young individuals with excellent quality of the bone fragments, careful techniques of reduction and fixation, avoiding additional surgical devascularization, should be performed, even in case of possible impairment of the vascular supply to the humeral head. In elderly individuals with osteoporotic bone and limited compliance throughout aftercare, humeral head replacement may be indicated less restrictively. In the latter group hemiarthoplasty generally can be expected to result in painfree shoulders. However, recovery of function and range of motion are much less predictable.

[Complex trauma of the shoulder girdle]

Complex injuries of the shoulder require differentiated management. Interestingly there is a relative lag of warranted information on this subject. Generally the different lesions are discussed separately. However it is not acceptable to simply add the standard diagnostic and therapeutic measures, because major tactic, strategic and rehabilitation incompatibilities could occur. Diagnostic and therapeutic difficulties are frequent for the following injuries: complex proximal humerus dislocation fractures, dislocation fractures with associated lesions of the rotator cuff, posterior dislocation fractures, peri- and intraarticular segmental fractures and fractures or dislocations associated with major neurovascular lesions. Increased awareness of the most relevant diagnostic and therapeutic aspects should contribute to optimize treatment protocols.

[Arthroscopic capsulo-labral repair and refixation with Mitek anchor in anterior shoulder instability]

From May 1992 to September 1995, 38 patients with recurrent anterior shoulder instability underwent arthroscopic stabilization. The arthroscopic stabilization was performed by capsular shifting and labral refixation using Mitek anchors, based on the Wolf procedure. Immediately after operation active assisted shoulder mobilization was initiated (elevation 60 degrees, external rotation 20 degrees less than contralateral shoulder). After a mean follow-up of 24 months (12-42 months) 30 patients were evaluated by means of the Rowe Score. Excellent and good results were achieved in 90% (n = 27) of patients and 80% had no restriction in sports activities. In 4 of the patients (13%) redislocation occurred. Analysis of the recurrence revealed no adequate trauma in two patients with preoperative multidirectional laxity. One had a trauma and the fourth showed no compliance in the early postoperative period. Compared to the open Bankart operation the described procedure shows a slightly higher rate of redislocations. However, the approach is less invasive and the subscapularis tendon with its proprioception remains intact.