Imaging the Terahertz Nanoscale Conductivity of Polycrystalline CsPbBr3 Perovskite Thin Films

Terahertz (THz) radiation is a valuable tool to investigate the electronic properties of lead halide perovskites (LHPs). However, attaining high-resolution information remains elusive, as the diffraction-limited spatial resolution (∼300 μm) of conventional THz methods prevents a direct analysis of microscopic effects. Here, we employ THz scattering scanning near-field optical microscopy (THz-sSNOM) for nanoscale imaging of cesium lead bromide (CsPbBr₃) thin films down to the single grain level at 600 GHz. Adopting a scattering model, we are able to derive the local THz nanoscale conductivity in a contact-free fashion. Increased THz near-field signals at CsPbBr₃ grain boundaries complemented by correlative transmission electron microscopy-energy-dispersive X-ray spectroscopy elemental analysis point to the formation of halide vacancies (V_Br) and Pb-Pb bonds, which induce charge carrier trapping and can lead to nonradiative recombination. Our study establishes THz-sSNOM as a powerful THz nanoscale analysis platform for thin-film semiconductors such as LHPs.

Band-Gap Tuning in All-Inorganic CsPbxSn1-xBr3 Perovskites

We investigate all-inorganic perovskite CsPb_xSn_1-xBr₃ thin films to determine the variations in the band gap and electronic structure associated with the Pb/Sn ratio. We observe that the band gap can be tuned between 1.86 eV (x = 0) and 2.37 eV (x = 1). Intriguingly, this change is nonlinear in x, with a bowing parameter of 0.9 eV; furthermore, a slight band gap narrowing is found for low Pb content (minimum x ∼ 0.3). The wide tunability of the band gap makes CsPb_xSn_1-xBr₃ a promising material, e.g., for a wide-gap subcell in tandem applications or for color-tunable light-emitting diodes. Employing photoelectron spectroscopy, we show that the valence band varies with the Pb/Sn ratio, while the conduction band is barely affected.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

Propiverine-induced accumulation of nuclear and cytosolic protein in F344 rat kidneys: isolation and identification of the accumulating protein

Male and female F344 rats but not B6C3F1 mice exposed for 104 weeks to propiverine hydrochloride (1-methylpiperid-4-yl 2,2-diphenyl-2-(1-propoxy)acetate hydrochloride), used for treatment of patients with neurogenic detrusor overactivity (NDO) and overactive bladder (OAB), presented with an accumulation of proteins in the cytosol and nuclei of renal proximal tubule epithelial cells, yet despite this, no increased renal tumor incidence was observed. In order to provide an improved interpretation of these findings and a better basis for human health risk assessment, male and female F344 rats were exposed for 16 weeks to 1000 ppm propiverine in the diet, the accumulating protein was isolated from the kidneys via cytosolic and nuclear preparations or laser-capture microdissection and analyzed using molecular weight determination and mass spectrometry. The accumulating protein was found to be d-amino acid oxidase (DAAO), an enzyme involved in amino and fatty acid metabolism. Subsequent reanalysis of kidney homogenate and nuclear samples as well as tissue sections using western blot and DAAO-immunohistochemistry, confirmed the presence and localization of DAAO in propiverine-treated male and female F344 rats. The accumulation of DAAO only in rats, and the limited similarity of rat DAAO with other species, including humans, suggests a rat-specific mechanism underlying the drug-induced renal DAAO accumulation with little relevance for patients chronically treated with propiverine.

[Indirect MR-arthrography in the follow up of autologous osteochondral transplantation]

PURPOSE

To evaluate the spectrum of findings in indirect MR-arthrography following autologous osteochondral transplantation.

PATIENTS AND METHODS

10 patients with autogenous osteochondral homografts underwent indirect MR-arthrography at three, 6 and 12 months postoperatively. The MR protocol at 1.5 T comprised unenhanced imagings with PD- and T2 -weighted TSE- sequences with and without fat-suppression as well as T1 -weighted fat-suppressed SE-sequences before and after i.v. contrast administration and after active joint exercise. Image analysis was done by two radiologists in conference and comprised the evaluation of signal intensity (Sl) and integrity of the osseous plug and the cartilage surface, as well as the presence of joint effusion or bone marrow edema.

RESULTS

At three months, all cases demonstrated a significant bone marrow edema at the recipient and donor site that corresponded to a significant enhancement after i.v. contrast administration. The interface between the transplant and the normal bone showed an increased Sl at three and 6 months in T2 -weighted images as well as in indirect MR-arthrography. The marrow signal normalized in most cases after 6 to 12 months, indicating vitality and healing of the transplanted osteochondral graft. The Sl of the interface decreased in the same period, demonstrating the stability of the homograft at the recipient site. The osteochondral plugs were well-seated in 9/10 cases. Indirect MR-arthrography was superior to unenhanced imaging in the assessment of the cartilage surface. Cartilage coverage was complete in every case. The transplanted hyaline cartilage as well as the original cartilage showed a significant increase of the Sl in indirect MR-arthrography, that did not change in follow up studies. There were no pathological alterations of signal and thickness alterations of the transplanted cartilage in follow up investigations.

CONCLUSION

Indirect MR-arthrography is a useful diagnostic tool following autologous osteochondral transplantation. Assessment of transplant vitality, osseous fixation and stability is possible.

Low-field MR arthrography of the shoulder joint: technique, indications, and clinical results

In the age of cost containment and urgent reductions in health care expenditures, new options have to be explored to satisfy both diagnostic requirements and economic limitations. The introduction of low-field MR systems for assessment of joint disorders seemed to be an option for lower costs. The purpose of this article is to summarize available experiences with low-field MR arthrography of the glenohumeral joint with respect to image quality and diagnostic accuracy in detecting labral and rotator cuff lesions. Up to now, there has been only a limited number of studies available dealing with low-field MR arthrography of the glenohumeral joint. They reveal that, despite a minor image quality in comparison with high-field imaging, low-field MR arthrography of the shoulder allows for sufficient evaluation of intra- and extra-articular structures in the detection of major abnormalities such as glenohumeral instability or rotator cuff disease. Furthermore, open-configured MR scanners enable kinematic studies: Besides the analysis of normal motion, pathological findings in patients with instabilities and impingement syndrome can be delineated. They further offer the possibility for performing MR imaging-guided arthrography of the shoulder. This was first described using an open C-arm scanner with a vertically oriented magnetic field so that MR arthrography may be performed in one setting.

Long-term results after operative treatment of femoral neck fractures with ceramic head prostheses

From 1985-1990, a total of 277 elderly patients underwent hemiarthroplasty using a ceramic head prosthesis. Average patient age was 81.7 years. Of these, 77 patients were available for follow-up examination in 1993. A standardized score was calculated assessing activity, gait, and hip pain; the average score was 58 out of 78 possible points. Three patients had hip pain, and in 4 patients, radiographic examination revealed protrusio acetabuli. Two of 4 patients underwent revision surgery for replacement of the cup, leaving the stem in situ. Because of the small number of prosthetic-related complications, hemiarthroplasty using a ceramic head prosthesis is the recommended surgical treatment for femoral neck fractures in elderly patients. In the rare patient with protrusio acetabuli, revision surgery can be performed to replace the cup, leaving the stem in situ.

[Sensitivity of magnetic resonance tomography in detecting meniscus tears]

In order to assure diagnostic accuracy, 172 knee joints were examined prospectively by MRI. After MRI, all knee joints were examined by arthroscopy. Tears of the medial meniscus were found in 102 patients, the lateral meniscus showed a tear in 29 cases. Assuming that arthroscopy represents the golden standard of diagnostic measure concerning the knee joint, it can be stated that false-positive MRI findings on the medial and lateral meniscus were diagnosed in three cases and false-negative MRI findings were diagnosed for two knee joints regarding the medial meniscus and four times regarding the lateral meniscus. For the medial meniscus a sensitivity of 98%, a specificity of 96%, an accuracy of 94%, and the positive and negative value of prediction were calculated at 97% each. Regarding the lateral meniscus, a sensitivity of 85%, a specificity of 98%, an accuracy of 92%, a positive predictive value of 88%, and a negative predictive value of 85% were found. Under the prerequisite that the MRI is carried out correctly and assessed by an experienced radiologist, the accuracy of the MRI for meniscus diagnosis is almost equivalent to the one by arthroscopy. Under these conditions, MRI can be recommended when no safe and sufficient clinical diagnosis can be made. The rate of unnecessary arthroscopies with a pure diagnostic purpose can be lowered significantly by means of MRI.

Minimally invasive plate fixation in femoral shaft fractures

Bridge-plating with its advantages in terms of vascularity and bone healing is a well established procedure today in the treatment of comminuted femoral fractures. Bridge-plating means that the fracture site is not interfered with during the operative procedure. This paper introduces a surgical technique in which the plate is inserted through isolated proximal and distal incisions only, behind the vastus lateralis. Alignment is secured by the plates, the fracture site remains untouched, fixation and screw insertion is restricted to the proximal and distal main fragments. Longitudinal femoral fractures extending right into the trochanteric and or condylar areas are the main indication for minimally invasive plate fixations with angled blade plates or condylar screws since fractures which are restricted to the diaphyseal area are mostly treated by nailing today. The surgical trauma resulting from plating by proximal and distal incisions only is less than that associated with conventional techniques. Indirect reduction of femoral fragments is much easier since the integrity of the surrounding muscles and soft tissue is preserved, the fragments often being reduced simply by traction. Adjustment of rotation is an essential aspect requiring careful attention. For special indications, namely comminuted fractures affecting a large part of the femur and extending into the trochanteric or condylar areas, insertion of the plate via proximal and distal incisions only is a further development in bridge-plating which minimizes surgical trauma and operation time.

A new method of capillary electrophoresis for metabolites of coumarin

The metabolism of coumarin has been very widely investigated compared with other natural compounds. We know today that genetic variations lead to human groups with a high or low coumarin-metabolism. An effective capillary-electrophoresis method has been developed to study these effects on metabolic patterns. The seven most important metabolites can be analysed in one step. Therefore also small volume samples can be examined for phase-I-reactions (hydroxylation of coumarin) as well as for secondary reactions (e.g. glucuronidation or decomposition of the lactone-structure).

MR arthrography of the shoulder: comparison of low-field (0.2 T) vs high-field (1.5 T) imaging

The objective of this study was to compare the image quality, sensitivity, specificity, and diagnostic accuracy of an open low-field MR system (0.2 T) with a standard high-field MR system (1.5 T) after arthrography of the shoulder. Thirty-eight patients either with suspected chronic instability (n = 12) or rotator cuff abnormalities (n = 26) were examined. Intra-articular injection of diluted Gd-DTPA was followed in randomized order either first by imaging on an open 0.2-T system or on a 1.5-T system. The image material was evaluated independently by two radiologists in a blinded fashion with respect to overall image quality and the detection of rotator cuff as well as capsular and labral abnormalities. Surgical correlation was available in 27 (71%) of 38 patients. For both systems, sensitivity and specificity for rotator cuff tears were 100% each, and for labrum pathologies, these values were 100 and 93%, respectively. The agreement for detection of labral pathologies between low-field and high-field examinations was good (kappa = 0.69, kappa = 0.61). For the detection of full-thickness tears of the rotator cuff, the agreement between the low-field and high-field MR examinations was very good and significant (kappa = 0.94, kappa = 1, p < 0.001). Overall image quality was rated good in 17 (45%) and fair in 21 (55%) of 38 cases on the 0.2-T MR system, and good in 32 (84%) and fair in 6 (16%) of 38 cases on the 1.5-T system. Motion artifacts were considered low in 24 (63%) and moderate in 14 (37%) of 38 cases for the 0.2-T system and low in 34 (89%) and moderate in 4 (11%) for 1.5-T system. Based on our results, low-field MR compares favorably to high-field MR in the detection of major abnormalities of the glenohumeral joint, at least when MR arthrography is used. Disadvantages are the duration of the examination and thus the risk of reduced image quality caused by motion artifacts.

Naringenin and interindividual variability in interaction of coumarin with grapefruit juice

Grapefruit juice has been shown to enhance oral bioavailability of several drugs including coumarin. The degree of the interaction is highly variable among the individuals.

OBJECTIVE

The aim of the study was to evaluate the interindividual variability in the pharmacokinetic profile of three components of grapefruit juice (naringin/naringenin, scopoletin, umbelliferone) and to compare it with the pattern of coumarin-grapefruit juice interaction.

STUDY DESIGN

A two-set clinical study with the participation of 18 healthy volunteers was designed. In the first set of the experiment the total renal recovery of naringenin, scopoletin and umbelliferone within 13 hours after the intake of 1L grapefruit juice was estimated. Four individuals, who had demonstrated extremely high or extremely low excretion of the metabolites in the first set, were selected for the second set. The subjects took 10 mg coumarin with 1L grapefruit juice vs 10 mg coumarin with 1 L water in a cross-over manner. The interaction pattern was evaluated according to the time-course curves of 7-hydroxycoumarin (main metabolite of coumarin) excreted with urine. The detailed time-course excretory profiles of naringenin and scopoletin from grapefruit juice were also obtained.

RESULTS

The screening demonstrated a significant interindividual variability in the renal excretion of naringenin (max/min > 15), scopoletin (max/min = 6.2), umbelliferone (max/min = 3.3). The interaction between coumarin and grapefruit juice has been observed by increase in the total recovery of 7-hydroxycoumarin up to 3 mg and by delay in time of its excretion by 2-3 hours. This interaction has been observed in 3 of 4 subjects and correlated with naringenin amounts in the urine. The mechanism and the sites of the interaction, as well as the causes for its wide interindividual variability are discussed in the paper.

Injuries of the lateral collateral ligaments of the ankle: assessment with MR imaging

The aim of this study was to evaluate the ability of MRI to display injuries of the lateral collateral ligamentous complex in patients with an acute ankle distorsion trauma. The MR examinations of 36 patients with ankle pain after ankle distorsion were evaluated retrospectively without knowledge of clinical history, outcome and/or operative findings. The examinations were performed on a 1. 5-T whole-body imager using a flexible surface coil. The signs for ligamentous abnormality were as follows: complete or partial discontinuity, increased signal within, and irregularity and waviness of the ligament. The results were compared with operative findings in 18 patients with subsequent surgical repair. Eighteen patients with conservative therapy had a follow-up MR examination after 3 months. There was 1 sprain, 3 partial and 32 complete tears of the anterior talofibular ligament, and 5 sprains, 5 partial, and 7 complete tears of the calcaneofibular ligament. There were no lesions of the posterior talofibular ligament. Compared with surgery, MRI demonstrated in 18 of 18 cases the exact extent of anterior talofibular ligament injuries and underestimated the extent in 2 of 8 cases of calcaneofibular ligament injury. In patients with follow-up MRI after conservative therapy, a thickened band-like structure was found along the course of the injured ligament in 17 of 18 cases. The absence of ligament repair after conservative treatment was confirmed during operative revision in one case. The MRI technique allows for grading of the extent of injury of the lateral collateral ligamentous complex after acute ankle strain. It seems to be suitable for monitoring the healing process after conservative-functional treatment of ligament tears.

[Low-field MRI of the knee joint: results of a prospective, arthroscopically controlled study]

PURPOSE

To define the diagnostic accuracy of an open low-field MR unit (Magnetom Open, Siemens, Erlangen) in traumatic knee lesions.

MATERIALS AND METHODS

The MRIs of 150 patients were prospectively evaluated by two independent readers with different experience levels. The study protocol included a proton-density weighted SE-sequence in the sagittal, a T2.-weighted Flash-2D-sequence in the coronal, and a 3D-acquisition (DESS) in the axial plane. 75 patients were treated either conservatively or operatively.

RESULTS

Based on arthroscopy as the gold standard, the sensitivities, specificities, and diagnostic accuracies for lesions of the medial and lateral meniscus, the anterior cruciate ligament (ACL), the hyaline cartilage, and the posterior cruciate ligament (PCL) were 92%, 92% and 92%, 83%, 93% and 92%, 95%, 96% and 96%, 74%, 93% and 85%, and 100%, respectively, for reader 1. The values for reader 2 were 81%, 74% and 77% (medial meniscus), 61%, 86% and 80% (lateral meniscus), 79%, 95% and 91% (ACL), 48%, 91% and 73% (hyaline cartilage), and 100% each (PCL), respectively. There were no statistical differences between the two readers (Fisher's Exact Test, 95%-confidence interval).

CONCLUSIONS

Using a time-consuming examination protocol, the diagnostic accuracies of the open low-field MR unit are well comparable to those obtained with mid- or high-field units. Although not statistically significant in this study, the experience level of the examiner seems to be of considerable clinical relevance.

[MRI of knee ligaments: error analysis with reference to meniscus and anterior cruciate ligaments in an arthroscopic controlled patient cohort]

PURPOSE

To categorise discrepancies in findings of the menisci and anterior cruciate ligament (ACL) between arthroscopy and MRI.

MATERIALS AND METHODS

The MRIs of 236 patients were retrospectively analysed by an experienced radiologist without knowledge of clinical and/or operative findings. Discrepancies in arthroscopic findings were reevaluated together with the arthroscopist to determine their cause of error.

RESULTS

The diagnostic accuracies for injuries of the medial and lateral meniscus and the ACL were 92.4%, 92.4%, and 94.1%, respectively. For the menisci, causes for discrepancies in findings (n = 31) were: overinterpretation of central signal intensities with contact to the meniscal surface but without disturbance of the meniscal contour as a tear (n = 12), insufficient arthroscopie evaluation of the knee joint (n = 11), overlooked tears on MR imaging (n = 6), misinterpretation of normal anatomic structures (n = 1), "magic angle" phenomenon (n = 1), and missed tears at MRI (n = 1). Causes for discrepancies for the ACL (n = 18) were: nearly complete versus complete rupture either at MRI or arthroscopy and vice versa (n = 9), insufficient arthroscopic evaluation (n = 6), insufficient MRI technique (n = 2), and overlooked tear on MR imaging (n = 1).

CONCLUSIONS

Discrepant findings between MRI and arthroscopy may be also due to an insufficient arthroscopic evaluation in clinical routine. The close cooperation between surgeons and radiologists improves the understanding of the methods of each other.

[Use of information systems for direct surgical patient management]

The aim of this prospective study was to evaluate the use of a modern computer-based hospital information system for the management of patients in our surgical department. The results showed that the information system was well accepted by the medical staff and found to be useful throughout daily work. In addition, they justify the effort to install and maintain such a system.

Retrograde nailing of humeral shaft fractures

The use of intramedullary nailing in the upper extremity is still controversial. Those who have experience with antegrade nailing have either great enthusiasm or strong criticism for the procedure. Criticism of the procedure is because of the trauma that can occur to the rotator cuff and possible impingement syndrome, which can occur after antegrade nail insertion. The technique of retrograde nail insertion with the unreamed humeral nail is described in detail. In a series of 190 retrograde nailings performed in a prospective multicenter study, the most frequent intraoperative problems were fissure or avulsion at the entry portal (n = 8; 4.2%) and secondary radial nerve palsy (n = 8; 4.2%). All radial nerve palsies recovered spontaneously. Sixty-eight patients were followed up until the fractures healed. There were five (7.4%) bone healing problems. Four of five could be solved with use of the unreamed humeral nail in a second operative procedure, whereas the fifth bone healing problem required plate osteosynthesis. Function of the shoulder and elbow joint was excellent in 89.7% and 88.3% of the patients, respectively. Retrograde humeral nailing is a safe and reliable procedure if done properly. It is a valuable stabilization technique for acute and pathologic fractures and for pseudarthrosis. Bone healing problems after unreamed humeral nailing must be analyzed individually, but they can be treated with the same implant in combination with cancellous bone grafts, reaming, additional hardware, or intrafragmentary compression.

[Efficacy of ultrasound controlled direct reposition of fragments of the posterior vertebral body facet]

To calculate canal compromise and decrease of midsagittal diameter caused by retropulsion of fragments into the spinal canal we analyzed the pre- and postoperative computed tomographies of 32 patients with unstable thoracolumbar burst fractures treated by USS (universal spine system). Our intention was to examine the efficiency of ultrasound guided repositioning of the dispaced fragments which was performed in all 32 cases. We found a clear postoperative enlargement of canal area (ASP preoperatively 55%, postop. 80%) and midsagittal diameter (MSD preop. 58%, postop. 78%). 10 of 13 patients presented a postoperative improvement of neurological deficit, no neurological deterioration occurred. Fractures with neurological deficit showed more canal compromise (52%) and less midsagittal diameter (MSD compromise 51%) than those without (40% or 39%). There was no correlation between the percentage of spinal canal stenosis and the severity of neurological deficit. Below L 1 the spinal canal is greater than between Th 11 and L 1, so a more important spinal stenosis is tolerated. In case of unstable burst fractures with neurological deficit the ultrasound guided spinal fracture reposition is an effective procedure concerning the necessary improvement of spinal stenosis: an additional ventral approach for the revision of the spinal canal is unneeded. In fractures without neurologic deficit the repositioning of the displaced fragments promises an avoidance of long-term damages such as myelopathia and claudicatio spinalis.

[Low-field MR arthrography of the shoulder: early results using an open 0.2T MR system]

PURPOSE

To assess the practicability and image quality of doing MR arthrography of the shoulder using a 0.2T system.

PATIENTS AND METHOD

60 patients (24 with chronic instability, 36 with impingement syndrome) were examined in an open 0.2T MR apparatus (Magnetom Open, Siemens). After the intra-articular injections of 15-20 ml of a 2 mmol Gd-DTPA solution, coronary STIR, T1-weighted, sagittal and axial T2*-weighted FLASH 2D sequences were performed. 21 patients subsequently underwent surgery.

RESULTS

Image quality of the T1- and T2*-weighted FLASH 2D sequences was regarded as good or adequate and movement artifacts were minor or moderate. STIR sequences were statistically significantly worse in respect of image quality and movement artifacts (p < 0.001, p < 0.005). The sensitivity and specificity in the diagnosis of rotator cuff rupture as confirmed by surgery was 100% (labrum lesions 100%, 93%). Agreement in the diagnosis of rupture of the supraspinatus and infraspinatus tendons was 0.93 and 0.65.

CONCLUSION

MR arthrography of the shoulder using an open 0.2 T MR system provides adequate information concerning the intra articular structures of the joint. The disadvantage is the prolonged duration of the examination with the risk of poor image quality resulting from movement artifacts.

The character of inhibition of the metabolism of 1,2-benzopyrone (coumarin) by grapefruit juice in human

OBJECTIVE

Constituents of grapefruit juice are known to interfere with mammalian cytochrome P450 isozymes such as intestinal CYP3A4 and hepatic CYP2A6, lowering the biotransformation of drugs and increasing their bioavailability. The aim of this study was to investigate whether the presence of naringin is demanded for the inhibition of the coumarin 7-hydroxylase in man or other compounds are responsible for it.

METHODS

In cross-over studies, doses of 10 mg coumarin, together with combinations of grapefruit juice, water and naringin, were given orally to one healthy male volunteer, We investigated increasing amounts of grapefruit juice, keeping the volume of liquid constant at 1 L; increasing doses of naringin given in water; increasing amounts of juice, keeping the dose of naringin constant; or increasing doses of naringin, keeping the amount of juice constant. Urine samples were collected up to 24 h after dosing and 7-hydroxycoumarin was quantified fluorimetrically in urine hydrolysates after HPLC separation to determine the excretion rates.

RESULTS

While increasing amounts of grapefruit juice delay the excretion of 7-hydroxycoumarin by 2 h, increasing doses of naringin in water up to twofold (i.e. naringin content of 2 L grapefruit juice) do not cause any alteration in the time course of excretion. Experiments with increasing amounts of juice, keeping the dose of naringin constant, indicate that the inhibitory potency of small amounts of grapefruit juice can be amplified by naringin. The same is true when the ratio between juice constituents and naringin is enhanced up to threefold by adding naringin.

CONCLUSION

As naringin alone is ineffective, the inhibitory effect of grapefruit juice on the metabolism of coumarin is caused by at least one compound other than naringin. The persistency of the primary inhibitor not identified yet can obviously be modulated by the naring(en)in-system.

[Magnetic resonance tomography examination of thoracolumbar spinal fractures after fixateur interne stabilization]

To analyse the possible injuries of vertebral segments, especially the disc, after unstable thoracolumbar fractures stabilised with AO internal fixator, we performed magnetic resonance imaging (MRI) of the traumatised region after implant removal. There were two aspects of disc degeneration (DD):(1) biochemical changes and (2) structural damage. MRI detects biochemical processes as one aspect of DD that is often small even in the presence of greater structural damage of the nucleus pulposus caused by fracture. None of the patients presented with structural failure of the anulus fibrosus, which is the essential structural component of the vertebral segments with regard to stability. We observed biochemical changes more often in the lower of the two fracture-adjacent discs and alterations of discal shape more often in the upper of the two, whereas loss of height concerned both discs to approximately the same degree. The supporters of upper-disc resection in thoracolumbar fractures justify their procedure among other things with the structural disc damage, such as alteration of shape and loss of height (altogether more frequent in the upper disc). Our observations that a disc with a structurally altered nucleus pulposus can be biochemically intact and can show an intact anulus fibrosus are arguments in favour of disc preservation. With regard to the upper disc, the widespread opinion that complete and regular disc damage requires a resection has to be revised. The question of whether the lower disc should be resected more often because of its greater biochemical changes cannot be answered by the present study alone. Besides the excellent static information in all anatomical structures of the vertebral column available by MRI, a repeat examination in a prone position yields dynamic information on the spinal cord in the case of suspected dorsal adhesions.

[Paget's disease of the proximal ulna--a rare monostotic manifestation]

Bone changes of the upper extremity are rare manifestations of the M. Paget disease. Most frequently the disease affects the lower extremities, the pelvis followed by the calvarium and others. The rare asymptomatic, monostotic manifestation of Paget's disease of the left proximal ulnae of a 59 year old woman and the way of diagnosis is described. Symptomatic skeletal lesions are detected by radiological examination, bone scintigraphy reveals asymptomatic lesions. Laboratory tests (Alkaline serum phosphatase, Hydroxyproline in urine) monitor the activity of the disease.

[Results of primary unreamed tibial nailing of tibial fractures with severe open or closed soft tissue injuries]

Primary stabilization was performed in 72 tibial fractures with sever open (n = 37) or closed (n = 35) soft tissue injury using unreamed interlocking nails. In 60 (83%) cases the fractures healed without additional procedures. There were 2 cases of osteitis, but both these fractures healed after removal of the nail or after reamed nailing. In 9 patients with delayed union reamed nailing (n = 8) or bone grafting (n = 1) led to healing. In 1 patient with hypertrophic pseudarthrosis, union was achieved after substitution of a reamed nail for the anreamed nail. The infection rate was similar to that observed with external fixation. More secondary procedures, such as bone grafting or a change of the osteosynthesis technique, are necessary with external fixation than with unreamed nailing. Further advantages of unreamed nailing are the internal treatment of the fracture and the patient's greater comfort. Therefore, unreamed nailing can be recommended for the primary treatment of tibial fractures with severe open or closed soft tissue trauma.

[Systemic complications in intramedullary nailing]

Today intramedullary nailing is the treatment of choice in stabilizing femoral and tibial diaphysial fractures because of its superior bone healing compared to other forms of osteosyntheses. By interlocking, the indication can be extended to all fractures in which interlocking bolts can be fixed in the proximal and distal main fragment. Küntscher's principle of elastic clamp has changed to intramedullary splinting. With that method reaming is limited to a few reaming processes, and unreamed nailing has become possible. Today implants start at a diameter of 9 mm. The diameter of implants of all manufacturers is less than a few years ago. Since the importance of embolization by increasing the intramedullary pressure as a result of reaming is accepted, the question arises concerning the clinical relevance of embolization if reaming is restricted and unreamed nails are applied. In our own investigations, relevant intravasation of bone marrow content appeared only in reamed femoral nailing. The bone marrow cavity of the tibia is smaller, the configuration of the tibia allows more back-streaming of the content, and the venous drainage system in the distal tibia is much less extensive than in the supracondylar area. All pulmonary complications in the literature are reported after nailing of femoral fractures. Therefore, systemic complications in intramedullary nailing are only a problem in femoral fractures. The pathophysiological connection between intramedullary pressure increases and pulmonary impairment is not clarified in detail. Relevant content of the bone marrow cavity is not only bone marrow, but also the blood with which the marrow cavity is refilled after each reaming process and which passes into the circulation during the following reaming. This blood is activated concerning coagulation. By reaming, the pathogenic content of the bone marrow cavity is embolized, which can become clinically relevant if cofactors are present. Cofactors are volume deficit, shock, lung contusion and pre-existing pulmonary impairment. These conditions can never be excluded before primary stabilization after trauma. Today the importance of systemic complications during unreamed nailing is controversial. Our experimental and echocardiographic investigations clearly show that the velocity of the nail into the bone marrow cavity and the gap between the nail and cortical bone at the entrance in the distal fragment determine the amount of embolized material. By carefully inserting the nail and choosing thin nails with a correct length, which can gain stability by fixation in the condylar area and not by clamping in the distal fragment, echocardiography reveals only minimal embolization. Therefore unreamed nailing is the treatment of choice, if the situation of the patient allows the procedure of nailing in itself. Multitrauma patients in shock or with unstable circulation should be stabilized primarily with external fixation. After consolidation, early change to an intramedullary nail should be performed.

Metabolic and analytical interactions of grapefruit juice and 1,2-benzopyrone (coumarin) in man

OBJECTIVE

Grapefruit juice is known to inhibit mammalian cytochrome P450 isozymes such as CYP3A4. The aim of this study was to investigate the influence of the juice on the fate of coumarin (1,2-benzopyrone) metabolized by CYP2A6 in man. Its potentially inhibitory effect was examined when low and high amounts of grapefruit juice were taken.

METHODS

In crossover studies, doses of 10 mg coumarin (Venalot) were given orally to an healthy male volunteer. The drug was taken either with water or with grapefruit juice, at different volumes (300 ml or 4 x 250 ml at intervals of 30 min). Urine samples were collected up to 24 h after dosing. After in vitro hydrolysis they were analysed fluorimetrically for umbelliferone, the metabolite of coumarin, and cumulative excretion curves were established. HPLC and TLC served to identify fluorescent metabolites from the juice.

RESULTS

If coumarin is given in water its excretion is complete after 6 h and 70% of the dose is recovered. Grapefruit juice (300 ml) given simultaneously slightly retards the appearance of the fluorescent metabolite in the urine within the first few hours. The recovery of coumarin remains unaffected. One litre of juice enhances the delay and increases the recovery of coumarin to nearly 100%. Respective controls with grapefruit juice alone lead to remarkable excretions of a fluorescent material identified as conjugated scopoletin, which strongly interferes with the analysis of the coumarin experiment. The precursor of scopoletin is widely present at different concentrations in commercially available grapefruit juices. However, the autoinhibition of the juice is correlated neither to the concentration of naringin nor to that of scopoletin.

CONCLUSION

Only grapefruit juice given at high doses (1 L) retards the appearance of the main metabolite of coumarin administered orally but increases its recovery. Due to scopoletin formed from the grapefruit juice, experiments especially with coumarin are strongly affected.

Knowledge retrieval as one type of knowledge-based decision support in medicine: results of an evaluation study

We report on a prospective, prolective observational study, supplying information on how physicians and other health care professionals retrieve medical knowledge on-line within the Heidelberg University Hospital information system. Within this hospital information system, on-line access to medical knowledge has been realised by installing a medical knowledge server in the range of about 24 GB and by providing access to it by health care professional workstations in wards, physicians' rooms, etc. During the study, we observed about 96 accesses per working day. The main group of health care professionals retrieving medical knowledge were physicians and medical students. Primary reasons for its utilisation were identified as support for the users' scientific work (50%), own clinical cases (19%), general medical problems (14%) and current clinical problems (13%). Health care professionals had accesses to medical knowledge bases such as MEDLINE (79%), drug bases ('Rote Liste', 6%), and to electronic text books and knowledge base systems as well. Sixty-five percent of accesses to medical knowledge were judged to be successful. In our opinion, medical knowledge retrieval can serve as a first step towards knowledge processing in medicine. We point out the consequences for the management of hospital information systems in order to provide the prerequisites for such a type of knowledge retrieval.

[Rupture of lateral ligaments of the ankle joint: MR imaging before and after functional therapy]

PURPOSE

Documentation via MRI of the healing of ruptured lateral collateral ankle ligaments after functional therapy.

PATIENTS AND METHODS

35 patients with ankle sprain were examined by MRI and stress radiographs, 13 were operated afterwards, 22 patients underwent a functional conservative therapy and were examined by MRI and stress radiographs and second time after three months.

RESULTS

MRI reports were correct in 12 of 13 operated cases. After conservative therapy we did not find any disrupted ankle ligament. MRI showed intact ligaments thickened by scar.

CONCLUSION

MRI is able to show injuries of the lateral collateral ankle ligaments and demonstrates the healing by scar after conservative therapy.

[MRI studies on the distensibility of cruciate ligaments of healthy knee joint]

AIM

Examination of the distensibility of the cruciate ligaments to evaluate the tense plasty of the cruciate ligaments.

MATERIAL AND METHOD

A functional MR study was performed using a Magnetom Open (0.2 Tesla, Fa. Siemens). We measured the length and width of the anterior and posterior cruciate ligament in volunteers (n = 12), age 20-40. We examined in 4 knee positions between maximal extension and maximal flexion.

RESULTS

Using the Wilcoxon test, the statistics do not show any significant difference between the length and width of the cruciate ligaments in the monoxial movement.

CONCLUSION

Our results may support the operative tense plasty of the cruciate ligaments although the entire complex mechanical system has not been examined.

[The value of MR tomography in traumatic patella dislocations]

PURPOSE

To describe the MR imaging findings in patients with lateral patellar dislocation.

MATERIAL AND METHODS

The MRIs of 31 patients with patellar dislocation were evaluated retrospectively. Arthroscopic surgery was performed in 23 cases.

RESULTS

Hemarthrosis was found in 30/31, contusions of the lateral femoral condyle in 30/31 and of the medial patellar facet in 26/31 cases. Injury of the medial patellar retinaculum was seen in 28/31 cases. Osteochondral fractures were found in 18 patients; compared to arthroscopy there were one false-positive and 5 false-negative findings concerning loose cartilage bodies. In 7 cases, patellar dislocation was not suspected before MR imaging.

CONCLUSION

Hemarthrosis, lateral femoral and medial patellar contusion, and retinacular disruption are typical findings after lateral patellar dislocation. A careful search for free osteochondral fragments is mandatory as it influences the indication and performance of arthroscopic surgery.

[The "inserted" condylar plate]

Twelve extensive segmental and comminuted fractures of the femur affecting the metaphyseal areas (7 times proximal, 5 times distal) and the diaphysis were treated with extremely long condylar plates (16 to 20 holes). The condylar plates were inserted via a proximal and a distal incision leaving the Musculus vastus lateralis intact at the fracture site in all cases. Following standard preparation of the blade position using the seating chisel, the condylar plate was inserted behind the musculus vastus lateralis with the blade pointing towards the surgeon. The condyles or the trochanteric area were tilted slightly and the plate was turned 180 degrees and driven home. No screws were inserted in the area of the fracture, in particular, lag screws were not used. Ten out of 12 fractures healed without problems, in 2 cases bone grafting was necessary. Three main observations resulted from analysis of the operations and subsequent clinical and radiographical assessments. In the presence of relatively intact soft tissue covering, an astonishingly good reduction of the fragments was achieved after restoration of leg length and extension. In the healing process, callus formed rapidly and provided medial support. The bone structure was found to be more homogeneous than in the case for plate fixation involving several screws at the fracture site around which considerable fluctuations in bone density frequently occur. The application of condylar plates behind the musculus vastus lateralis by only proximal and distal incision for osteosyntheses of extensive multifragmental fractures is a further development of bridge-plating and can be recommended for long fractures.

Parosteal osteosarcoma of the talus

A case of parosteal osteosarcoma in the very rare location of the talus is presented. The radiological, pathological, and clinical characteristics of parosteal osteosarcoma are described and the differential diagnosis discussed.

[Is there a connection between intramedullary pressure increase, bone marrow intravasation and deep venous thrombosis of the leg in endoprosthetics?]

Deep vein thrombosis still is a severe problem in hip replacement. Based on pathophysiological considerations, it is postulated that there is a connection between intramedullary pressure peaks, resulting intravasation of bone marrow, and the induction of deep vein thrombosis. The content of the bone marrow cavity can be considered active where coagulation is concerned. Intravasation may contribute to the development of deep vein thrombosis. In addition to medicamentous prophylaxis and early mobilization, a surgical technique also helps in the prophylaxis thrombosis. In this technique, intramedullary pressure increases are avoided as far as possible, which consequently minimizes intravasation of the content of the bone marrow cavity.

[The effect of bone marrow embolization on the choice of procedure in the stabilization of femoral fractures]

Because of an extended venous drainage system, especially in the supracondylar area, a pressure increase in the femoral cavity results in embolization of the contents of the bone marrow cavity. Bone marrow embolization alone is mostly not apparent clinically but together with cofactors it may result in severe pulmonary damage and occasionally even in death. Cofactors are volume deficit, shock, thoracic and polytrauma and preexisting pulmonary disease. In the field of traumatology a pressure increase in the femoral cavity regularly occurs during unavoidable movement of femoral fragments in traction, during reduction, intraoperatively during intramedullary nailing, and in hip replacement. A hematoma acts as a hydraulic transmitter. Early osteosynthesis within 24 h avoids permanent intravasation of moderate amounts of the contents of the bone marrow cavity. Concerning intramedullary nailing, there are considerable differences between reamed and unreamed nailing. Reaming always leads to high-pressure increases in the femoral cavity, resulting in embolization. Therefore, reaming should not be performed if cofactors of manifestation of pulmonary impairment are present. Unreamed nailing results in less intravasation, but is not entirely harmless, as considerable pressure increases occur in unreamed nailing as well. The gap between the nail and the entrance of the distal fragment is the decisive parameter. Not just the smaller intravasation of bone marrow during unreamed nailing is important. After each reaming process, the bone marrow cavity rapidly refills with blood, which is activated concerning coagulation and pressed into the circulation during the following reaming process. Because of superior bone healing, interlocking nailing is the treatment of choice in diaphysial femoral fractures. As far as the differential indications of reaming are concerned, the discussion is not yet closed. However, reaming should undoubtedly be restricted to a few reaming processes. Before unreamed femoral nailing, the width of the bone marrow cavity must be examined exactly. If the width of the bone marrow cavity, the patient's condition and experience of the surgeon allow unreamed nailing, this procedure can be recommended. As the venous drainage system of the tibia is not important compared to the femur, the question of reaming or not in tibial fractures is not influenced by the danger of embolization, but by soft tissue damage and the stability of interlocking bolts. In patients with femoral fractures and co-factors for the manifestation of pulmonary impairment, the choice of osteosynthesis type should take plating in its improved form into consideration, as this preserves the vascularity of the fragments.(ABSTRACT TRUNCATED AT 400 WORDS)

[Possibility for detecting HIV-1 in bone transplant by PCR using the HIV-1 microtiter plate assay]

It is known that HIV can be transmitted by allogenous bone transplantation. Hitherto neither chemical nor physical methods have existed to allow reliable disinfection and sterilization of bone specimens without reducing osteogenetic potency. Only demonstration or exclusion of the presence of HIV-1 in a bone specimen guarantees that infection will not occur. The method now presented for HIV detection is based on a polymerase chain reaction (PCR). This HIV microtiter-plate assay combines amplification of DNA molecules with a staining reaction. In cultures containing HIV-infected cells definite detection of viruses was possible when 50-100 cells per specimen were infected. Examination of 137 HIV-negative and 25 HIV-positive bone specimens showed sensitivity of 96% and specificity of 97.8% for the test. In subsequent studies, after drying on filter paper viral DNA was again demonstrable by the PCR. This means safe handling and uncomplicated transportation of non-infectious specimens to a central analysis laboratory are possible. This HIV test offers the possibility of quick and safe demonstration that specimens are free of HIV and is therefore likely to enhance the safety of bone transplantation considerably.

[2- to 7-year results of cement-free and cemented joint replacement in femoral neck fractures and coxarthrosis]

In 43 patients with cementless and 43 patients with cemented hip prosthesis (S+G hip system) a clinical and radiological follow up was performed 2-7 years after total hip replacement. In average the follow up period was 43 or 48 months. We found good or excellent results in 88% after cementless and 95% after cemented fixation. The results after cementless hip replacement were caused by loosening in the early postoperative period in 3 cases and more frequently thigh pain. In conclusion of our results and the expected later results after 10 years follow up we prefer the cementless fixation in patients under 60 years and cemented fixation in the group over 70 years. Patients between 60 and 70 years seems to benefit from a fixation with an cementless acetabular component and an cemented stem (hybrid prosthesis).

[Bone remodeling after reamed and unreamed intramedullary nailing. A histomorphometric study]

Experimental findings after unreamed nailing have indicated certain advantages for new bone formation in comparison to reamed nailing. It would be of interest to establish whether any essential differences can be determined in the extent and course of callus formation. To investigate this question, thin sections of bone from 16 tibiae (nailing after transverse osteotomy in sheep) were examined histomorphometrically the progress at the periosteal and interfragmentary surfaces of the remodelling callus being recorded separately after 4, 6 and 8 weeks. After unreamed nailing, more extensive and earlier formation of interfragmentary callus was observed. At 4 weeks postoperatively the remodelled periosteal bone surface was 158 mm2, which was 1.6 times that after the unreamed procedure (95 mm2). By 4 weeks after unreamed nailing the periosteal callus surface was already greater than 6 weeks after reamed nailing. On the basis of these experimental results the use of unreamed nailing can be recommended, especially for open fractures and fractures with severe soft tissue damage.

[Rotational stability of the thoracolumbar spine after interlaminar ultrasound window, hemilaminectomy and laminectomy. A comparative experimental study]

Intraoperative spinal sonography to check whether fragments have been successfully repositioned requires enlargement of the natural interlaminar window to 8 x 10 mm. The present study was performed to measure any rotational instability caused by such a laminotomy and compare it with that resulting when the conventional methods of checking the spinal canal, e.g. hemilaminectomy and laminectomy, are applied. The investigations were carried out in 10 human vertebral columns, in the area of T-12, L-2 and L-4. Torsional loads of up to 20 Nm were applied to the spines and axial rotations were recorded. Laminotomy, hemilaminectomy and laminectomy were done step by step. The loading-unloading cycles were achieved with initial axial rotation and decreasing torsional moment after measurement the dorsal manipulations. It was shown that interlaminar fenestration causes a hardly measurable instability. A laminotomy to 10 x 20 mm, allowing direct repositioning of the posterior vertebral surface, causes a 6% loss of stability. A significant decrease is caused by hemilaminectomy, with a 20% loss and by laminectomy, with 27% loss of rotational stability compared with the intact spine. Rotational instability of the spine causes severe pain and often has to be treated by spondylodesis. The present investigations show that the spinal canal should not be checked by hemilaminectomy or laminectomy. For this we now use intraoperative ultrasound.

[Results of implantation of uncemented porous metal hip prostheses]

72 patients having cementless spongy-metal hip prosthesis were reexamined by clinical and radiological check up two to seven years after implantation (average 43 months). In case of five patients hip prosthesis had to be changed due to loosening (no bony ingrowth n = 2, loosening of acetabular component due to technical faults n = 3). In correlation to clinical results 88% could be considered as excellent or good, 9% acceptable and 3% as inadequate. 10% of the patients complained about thigh pain. The typical radiological bony reactions of the surrounding bone are described. An evaluation of the radiological results can only be done under consideration of the clinical problems involved. In view of the positive results obtained in the recent time the use of spongy-metal hip prosthesis can be recommended for cementless hip joint replacement in case of younger patients. Especially in case of cemented hip joints which have become loose it will be an advantage to use spongy-metal hip prosthesis.

[Application possibilities of MR arthrography in diseases of the shoulder joint]

In a prospective study possible indications for MR arthrography of the shoulder were evaluated. 37 patients were examined before and after intraarticular administration of a 2-mmolar solution of Gd-DTPA. MR arthrography was performed if there was no joint effusion and/or an uncertain finding concerning the rotator cuff or the capsulolabral complex on plain MR images. MR arthrography leads to a better demonstration of labrum pathology in 11/22 patients and to a superior delineation of the capsuloligamentous apparatus in 20/22 cases. In 9/15 patients with impingement lesions MR arthrography allowed a differentiation of severe tendinitis from partial and small full-thickness tears of the rotator cuff. MR arthrography of the shoulder joint enhances the accuracy of MR in case of an uncertain finding on plain MR images.

[Bone healing after unreamed intramedullary nailing]

Good clinical results of unreamed nailing have been observed primarily in cases of open fracture. However, it is still unclear whether unreamed nailing is a suitable procedure for fractures that have previously been treated with reamed nailing. Since histological findings on bone healing after unreamed nailing were not available, an animal experiment on sheep was undertaken. The aim was to investigate whether there were differences in the nature of bone healing following reamed and unreamed nailing procedures. Fluorescence microscopy clearly showed that maximal callus formation occurred within 4 weeks after unreamed nailing and within 6 weeks after reamed nailing. Callus formation was also more prolific after unreamed than after reamed nailing. It was demonstrated by microradiography that bone regeneration progressed more rapidly, in terms of both periosteal and interfragmentary callus, after unreamed nailing. No disturbances of bone healing and no greater risk of pseudarthrosis were observed following unreamed nailing. Histological investigations showed that bone healing was faster after unreamed nailing and there was a reduced loss of vitality. This is of particular clinical relevance in the surgical treatment of fractures with severe soft tissue injury and of open and comminuted fractures. These results indicate that an extension of the indications for unreamed nailing should be considered.

[Technique of plate osteosynthesis of the femur]

When plating is performed for fixation of complex femoral fractures the need for medial buttress to give durable weight-bearing ability of the bone is mandatory. However the means of achieving this is controversial. Many authors are in favour of mechanical reconstruction of the medial buttress, if necessary with a bone graft. Alternatively, medial buttress can be achieved by means of a technique allowing biological fracture healing, which is only possible, when the vascularity of all fragments is preserved. In 39 cases of osteosynthesis with plates for complex femoral fractures the bridging technique was used at surgery, to avoid denudation of the fragments. All osteosyntheses were performed without the application of bone clamps. After minimal exposure of the femur at the lateral side only, the plates were fixed in the main proximal fragment with one screw, in the case of blade plates the blade was fixed without bone clamps too. Afterwards the main distal fragment was drawn up to the plate and fixed directly and with a screw. In 9 cases the plates were inserted behind the vastus lateralis muscle, preserving its continuity, and fixed distally with another screw. After fine checking of the fracture alignment for rotation and length the plates were fixed with four or five screws in each main fragment, all at sites distant from the fracture. Meanwhile, all 39 fractures have consolidated. There were no cases of infection. Bone grafting was necessary in 8 cases. Only in 2 cases were the defects located in the medial area. In 37 of the 39 osteosyntheses an excellent medial buttress was achieved by bone healing.(ABSTRACT TRUNCATED AT 250 WORDS)

[The value of the radiologic Lachman test in anterior cruciate ligament ruptures]

A radiologic Lachman test of both knees was performed in 35 patients with surgically verified tears of the anterior cruciate ligament (ACL). We found a mean anterior drawer of 3.2 mm for uninjured joints, 4.5 mm for isolated ACL-tears and 10.8 mm for complex ACL-injuries. Sensitivity of the radiological Lachman test was 95% for complex ACL-injuries as only 23% in case of isolated ACL-ruptures. Failure of diagnosis due to clinical investigation in case of ACL-ruptures could not be proved by means of radiological Lachman-test. Technical requirements and radiation exposure are further disadvantages. Clinically doubtful cases of acute knee injuries should therefore be investigated with other diagnostic procedures.

[Experimental studies in weakening the stability of the trochanter major by lateral fenestration]

A major disadvantage of the usual 130 degree angle plates when handling the fracture of the neck of the femur is the fact that the lateral corticalis of the femur is almost completely interrupted by the broad window at a biomechanical important and highly strained location. This often leads to the complications such as the breaking off of the greater trochanter or lack of stability etc. The experiment examines ten pairs of human femora for a decrease of stability, which results from the lateral fenestration for the osteosynthesis. One of the two bones out of a pair received a slit at a right angle concerning the axis of the femur, the other one a round hole. The slit was made into the proximal lateral femur as if preparing for the installation of a 130 degree angle plate. On the corresponding spot of the second bone a round hole was drilled. The remaining stability of the compact bone was measured by experimental pulling on the greater trochanter. Under the assumption that left and right femur have about the same stability, which was proven in one of the experiments, a significant disadvantage was found for the relatively wide slit.

[Treatment and results of ruptures of the patellar tendon]

Ruptures of the patellar ligament are rather uncommon. In younger individuals they are due to adequate trauma, in older individuals spontaneous ruptures occur after inadequate trauma. We observed eight traumatic (mean = 26.5 years) and eleven spontaneous ruptures (mean = 57.5 years) between 1980 and 1990. There is no alternative to surgical repair of the ruptured or torn-out patellar ligament. Tendon-repair with supportive wire-looping and early functional physiotherapy produces a good functional result. The outcome of patients treated in this manner shows persisting slightly muscular atrophy of minor degree and limited knee mobility with only a little all-day handicap.

[Detection of primarily unrecognized fractures in severely injured patients by skeletal scintigraphy]

Even in despite of diligent investigation clinical and radiological diagnostics can leave fractures unrecognized in seriously injured patients. Bone-scans of 53 patients revealed 68 additional fractures. In 45% of all cases the initial diagnosis was altered, 19% resulted in therapeutical consequences. Routine diagnostics should be supplemented by a bone-scan if clinical and radiological findings are not in line. A bone-scan can exclude any osseous lesion and can survey the full extent of injuries especially in the disoriented or unconscious patient.