Weight-bearing MRI with a knee flexion angle of 20°: a study on additional MRI investigation modalities to support a more accurate understanding of patellofemoral instability.

BACKGROUND: Diagnosing patellofemoral instability disorders correctly, weight-bearing MRI (WB-MRI) has become an option. Aiming for a best possible accuracy in displaying potentially underlying causes, the named MRI modalities were sporadically even investigated in different knee flexion angles. However, despite confirmed MRI-outcome-differences between WB-MRI and non-WB-MRI, none of the described MRI modalities have so far established themselves. Mainly this is due to an unfeasibility in daily clinical routine in regard to time and economic aspects. Thus, we intended to evaluate an additional but reduced patellofemoral MR-imaging solely in a relevant 20° of knee flexion under WB- and non-WB-MRI conditions. METHODS: Seventy-three subjects with and without patellofemoral instability were investigated under supine as well as under WB-MRI conditions in a 20° of knee flexion angle. Patellofemoral risk indices in the sagittal plane (Insall-Salvati-Index, Caton-Deschamps-Index, Patellotrochlear Index) and the axial plane (Patella tilt of Fulkerson and Sasaki) were detected and compared between the different MRI conditions. Significance, reliability and Cohen's effect size was calculated. RESULTS: Nearly all assessed indices showed significant differences between patients and controls in the different MRI positions. Comparing pairwise, all measured indices failed to show significant differences between the two MRI positions. However, patella tilt angles of the patient group showed an elevation from supine to WB-MRI (14.00 ± 7.54° to 15.97 ± 9.10° and 16.34 ± 7.84° to 18.54 ± 9.43°). Here, Cohen's d showed small to medium effects between supine and WB-MRI. CONCLUSION: In comparison to standard MRI in supine position, axial risk indices seem to be accentuated under WB-MRI and a knee flexion angle of 20°. In particular, symptomatic cases with inconspicuous conventional MRI imaging, additional MRI imaging only in the axial plane in a 20° of knee flexion could be beneficious and useful in clinical daily routine.

Serial clinical and MRI examinations after arthroscopic rotator cuff reconstruction using double-row technique.

PURPOSE: Rotator cuff reconstruction using arthroscopic double-row technique enables a better repair of the anatomical footprint at the tendon insertion. Objective of this serial study was to illustrate structural and functional results during recovery following double-row reconstruction. METHODS: Forty-five patients with mid-sized ruptures of the supraspinatus tendon were assessed prospectively and underwent arthroscopic surgery using the double-row technique. Rupture localization, size, form, and extent of retraction were recorded intraoperatively. Clinical and MRI follow-up examinations were carried out for all patients after 6, 12, 26, and 52 weeks. A A standard protocol was used during the follow-up examinations to determine tendon integration, signal changes in the tendon, extent of bone marrow edema near the enclosed absorbable suture anchors, muscle changes. The clinical results were correlated with the MRI appearance. RESULTS: After 26 weeks, the Constant score (CS) showed a highly significant increase for the first time with a value of 78 (p < 0.001). Tendon integration according to Sugaya showed a left shift over time, with higher CS-values for lower Sugaya classifications. Significant improvements in strength were first measured between the 26-week and 52-week follow-ups (9->19/p < 0.001). Highly significant improvement (p < 0.001) of the tendon signal and the fatty infiltration was found in the same time interval. The hypotrophy showed slight improvement, while a highly significant reduction of the bone marrow edema was found between weeks 12 and 26 (p < 0.001). There were no re-ruptures after week 26. CONCLUSIONS: The present serial study showed that it took 26 weeks to reach a significant clinical improvement concerning CS. With regard to tendon healing, no further deterioration of the structural results occurred between week 26 and week 52 postoperative. There were slightly but not significant better clinical results according to the the Sugaya classification. However, parameter "strength" was significantly increased between weeks 26 and 52. This was consistent with a significant decrease in the signal intensity at the repaired tendon site, an additional improvement in the fatty infiltration, and the atrophy according to Thomazeau in the same time interval. LEVEL OF EVIDENCE: I.

[Results from the German shoulder- and elbow arthroplasty register (SEPR) : Anatomic or reverse shoulder arthroplasty in B2-glenoids?] / Ergebnisse des deutschen Schulter- und Ellenbogenprothesenregisters (SEPR) : Anatomische oder inverse Prothese bei B2-Glenoid?

BACKGROUND: Anatomic shoulder arthroplasty in osteoarthritis with biconcave glenoid wear results in decreased functional results and a higher rate of early glenoid loosening. AIM: The aim of the data analysis of the German shoulder arthroplasty register was to clarify whether reverse shoulder arthroplasty can provide better functional results and a lower complication rate than anatomic arthroplasty in osteoarthritis with biconcave glenoid wear. METHODS: The analysis included 1052 completely documented primary implanted arthroplasties with a minimum follow-up of 2 years. In 119 cases, a B2-type glenoid was present. Out of these cases, 86 were treated with an anatomic shoulder arthroplasty, and in 33 cases a reverse shoulder arthroplasty was implanted. The mean follow-up was 47.6 months. RESULTS: The Constant score with its subcategories, as well as the active range of movement improved significantly after anatomic and after reverse shoulder arthroplasty. DISCUSSION: We observed no difference in functional results between both types of arthroplasty; however, reverse arthroplasty showed a significant higher revision rate (21.2%) (3% glenoid loosening, 6% prosthetic instability) than anatomic shoulder arthroplasty (12.8%) (11.6% glenoid loosening, 1.2% prosthetic instability), whereas anatomic shoulder arthroplasty showed a higher rate of glenoid loosening. Functional and radiographic results of both types of arthroplasty are comparable with the results reported in the literature, although our analysis represents results from an implant registry (data pertaining to medical care quality).

MRI-associated classification to evaluate the outcome after autologous reconstruction of the medial patellofemoral ligament: a preliminary study.

PURPOSE: Purpose of this study was to establish and validate an MRI-associated classification to graduate postoperative results of MPFL reconstructions. METHODS: 30 autologous MPFL reconstructions of 28 patients were evaluated by two independent raters using MRI. All grafts were assigned to a novel graduation system respecting the graft's anchoring insertions, its MRI signal appearance, continuity and tension and the differentiation relating to the surrounding soft tissue. RESULTS: All grafts could reliably be assigned to one of the subgroups by both raters. 86.6 % of the grafts could be classified A1 or B1, reflecting a correct positioning and a low to intermediate signal intensity. Only one graft had to be classified C3 (malpositioned, elongated). CONCLUSION: We were able to establish and validate an MRI-associated classification to graduate the postoperative outcome after MPFL reconstructions. Foresighted, the presented classification might support further decision making in case of unsatisfying postoperative results.

[Magnetic resonance imaging and computed tomography : What is important in orthopedics and traumatology]. / Magnetresonanz- und Computertomographie : Indikationsstellung in Orthopädie und Unfallchirurgie.

BACKGROUND: Magnetic resonance imaging (MRI) and computed tomography (CT) are established complementary tools for cross-sectional imaging in addition to standard x­rays in orthopedics and traumatology. OBJECTIVE: Illustration of possible applications of MRI and CT in acute and chronic joint diseases. MATERIAL AND METHODS: Summary of the relevant literature with focus on the validity of MRI and CT in depicting joint trauma and pathologies. In addition, description of pitfalls in evaluation of the images. RESULTS: The main focus of CT is the detailed visualization of fractures and deformities; however, MRI is the primary imaging technique for depiction of soft tissue pathologies, such as ligament tears and chondral lesions. Both imaging techniques are valuable in orthopedics and traumatology and complement each other in the development of treatment algorithms. CONCLUSION: Both MRI and CT are essential and complementing cross-sectional imaging techniques in the diagnostic procedures for joint pathologies in orthopedics and traumatology.

[Bone marrow edema and atraumatic necrosis of the femoral head : Therapy]. / Knochenmarködem und atraumatische Femurkopfnekrose : Therapie.

BACKGROUND: An increase in interstitial bony fluid occurs in bone-marrow edema (BME). The exact pathogenetic processes still remain unknown. BME is an unspecific finding that can occur on its own or accompany multiple diseases and pathologies. GOAL: Literature review and presentation of new guidelines. MATERIAL AND METHODS: This is a narrative literature review followed by current advice for the therapy of atraumatic osteonecrosis of the hip, based on the recently published S3-guidelines for this disease. RESULTS AND DISCUSSION: The differentiation of at least 3 different etiologies is proposed (mechanic, reactive and ischemic). Difficult, but important, is the distinction between the mostly painful, but benign entities (BME syndrome, bone bruise) and the progressive pathologies (osteonecrosis, arthritis, CRPS, tumour). Treatment options are dependent on etiology and clinic and can often be symptomatic. Core decompression is the surgical gold standard, leading to immediate pressure relief and therefore reduction in pain. Recently, it was shown that intravenous administration of Iloprost and bisphosphonates are also effective in achieving a reduction of BME and pain, with considerable improvement in the accompanying symptoms. The combination of core decompression and infusion seems to be another possible optimization ofthe therapy, in particular in the treatment of osteonecrosis.

Radiographic monitoring of the distal insertion of the calcaneofibular ligament in anatomical reconstructions of ankle instabilities: A preliminary cadaveric study.

BACKGROUND: The purpose of the study therefore was to determine radiographic landmarks that support the identification of the insertion site of the distal calcaneofibular ligament (CFL) in anatomic ankle ligament reconstructions. METHODS: In 10 lower limb cadaver specimens the midpoint of the distal CFL insertion was dissected and marked with a nail inserted orthogonally. On a standardized lateral radiograph in neutral ankle position a horizontal tangent was aligned to the deepest visible concavity of the tarsal sinus and one vertical tangent to the farthest posterior convexity of the talus. Additionally, a line was drawn from the radiographically marked distal CFL to the fibular insertion of the CFL to determine the CFL-fibular angle. RESULTS: In relation to the radiographic tangents intersection the mean deviation of the depicted CFL nails was 2.2mm [SD ± 1.1 mm] leading to an angular, circular to slightly oval 6 mm insertion. The scatter-plot of the marked positions convened along a line from the supposed fibular CFL insertion to the intersection in all cases. The mean CFL-fibular angle was 131.7° [SD ± 3.16°]. CONCLUSIONS: Determining a virtual intersection between a horizontal tangent aligned to the deepest visible concavity of the tarsal sinus and one vertical tangent aligned to the farthest posterior convexity of the talus on a standardized lateral radiograph in neutral ankle position supports an anatomic insertion of the distal calcaneofibular ligament most probably.

[The utilization of MRI by orthopaedic surgeons: requirements and limitations]. / Fachbezogene Anwendung der MRT in Orthopädie und Unfallchirurgie: Voraussetzungen und Limitationen.

BACKGROUND: The tendency in surgical fields to subspecialize continues. Diagnostic possibilities and surgical indications are becoming more and more sophisticated. As a consequence, surgeons in Germany have the possibility to acquire qualifications in magnetic resonance imaging (MRI) and are allowed to employ MRI scanners without consulting radiologists. AIMS: This article aims to describe the requirements to achieve this special qualification and to give a summary on the legal issues in this matter.

[The role of MRI in dislocations of the patella and other knee pathologies]. / MRT des Kniegelenks unter besonderer Berücksichtigung der Patellaluxation.

In addition to ultrasound and conventional x-ray, magnetic resonance imaging (MRI) plays an important role in the visualization of lesions of the knee. It allows the orthopaedic surgeon to safely detect ruptures of the cruciate ligaments, the meniscus, osteochondral lesions and other ligamentary structures such as the collateral ligaments and the medial patellofemoral ligament (MPFL). In patellar dislocations, risk factors for recurrent dislocations can be determined and the therapy can be adjusted accordingly.This articles aims to give the reader a comprehensive overview on current concepts and techniques in the use of MRI for lesions of the knee. It focuses on patellar dislocations, where MRI plays a dominant role in supporting decision making for the best therapeutic strategy.

[Weightings and sequences in magnetic resonance imaging in orthopedic surgery]. / Wichtungen und Sequenzen der Magnetresonanztomographie in der Traumatologie.

Magnetic resonance imaging (MRI) plays a very important role in the diagnosis of musculoskeletal conditions; its importance in orthopedic trauma continues to grow. To ensure optimal imaging and to be able to answer all clinically relevant questions, some prerequisites must be taken into account. Of uttermost importance is a functioning communication between surgeons and radiologists. To adapt the best sequences, the radiologist needs to know all suspected injuries and the mechanism of trauma. Second, the surgeon must have basic knowledge regarding this technology to optimally use all its possibilities. The aim of this article is to familiarize the reader with basic MRI in traumatology focusing on weightings and sequences.

[MRI in musculoskeletal imaging: possibilities and limitations]. / MRT-Untersuchungen bei Muskelverletzungen: Was ist sinnvoll?

Muscle injuries are the most frequent sport injuries in athletes. In addition to a thorough clinical examination and the history of the trauma mechanism, imaging modalities are required to correctly classify the injury and plan the future treatment and rehabilitation. The two major modalities are ultrasound and magnet resonance imaging (MRI). This article aims to give a comprehensive overview on the possibilities and limitations of MRI imaging in musculoskeletal injuries as well as insight into current development, classifications and technologies.

[Use of magnetic resonance imaging in orthopaedic trauma surgery: global needs analysis]. / Anwendungsgebiete der Magnetresonanztomographie in der Traumatologie: Ergebnisse einer weltweiten Umfrage.

BACKGROUND: Magnetic resonance imaging (MRI) plays a very important role in traumatology; however, clear guidelines and standard operating procedures do not exist on a large scale. The aim of this worldwide needs analysis was to gather detailed information on this imaging modality in the daily work of trauma and orthopedic surgeons and trainees, and to identify ways to optimize its application. Using the network of the"Arbeitsgemeinschaft für Osteosynthesefragen - Association for the Study of Internal Fixation" (AO/ASIF), participants who registered for a webinar on this topic were asked to complete a structured set of questions and simulated cases online. METHODS: A total of 442 participants from 69 countries registered for the webinar and 361 (81.6%) completed all or the main parts of the survey. The main reported barriers to the optimal use of MRI were high cost, long waiting time, a lack of communication between surgeons and radiologists, and a lack of experience and training in this technology. CONCLUSIONS: To address these barriers, a more structured curriculum in the training period of orthopedic and trauma surgeons may be required as well as the development of resources for continuing and self-directed learning.

[Magnet resonance imaging in common injuries of the wrist]. / Magnetresonanztomographie bei häufigen Verletzungen des Handgelenks.

Falling on the outstretched hand is a common trauma mechanism. In contrast to fractures of the distal radius, which usually are diagnosed on plain film radiographs, identifying wrist injuries requires further diagnostic methods, e.g., MRI or CT. This article provides a review of the use of MRI in the most common traumatic wrist injuries, including scaphoid fractures, TFCC lesions, and tears of the scapholunate ligament. Early and selective use of MRI as a further diagnostic method in cases of adequate clinical suspicion helps to initiate the correct treatment and, thus, prevents long-term arthrotic injuries and reduces unnecessary absence due to illness. MRI shows a high reliability in the diagnosis of scaphoid fractures and the America College of Radiology recommends MRI as method of choice after X-ray images have been made. In the diagnosis of ligament and discoid lesions, MR arthrography (MRA) using intraarticular contrast agent has considerably higher accuracy than i.v.-enhanced and especially unenhanced MRI.

[Evidence for treatment of acute syndesmosis injuries in sports]. / Evidenz der Versorgung der akuten Syndesmosenverletzung im Sport.

Injuries of the distal syndesmosis often accompany acute ankle sprains especially in professional team sports. While small partial syndesmosis lesions can often be missed as a consequence of impressive symptoms due to ventrolateral capsuloligamentous injuries, higher grade injuries of the syndesmosis can mostly be diagnosed without any problem. Furthermore, there is a consensus concerning the necessity of operative treatment in significantly unstable situations as well concerning conservative treatment of incomplete partial lesions. Consequently, the greatest challenge regarding diagnostic tools, quantification and optimal therapy arises in the most common form of sport-associated, complete or partial lesions of the distal syndesmosis. This review article summarizes sports-associated injuries of the distal tibiofibular syndesmosis considering the current literature and placing the emphasis on the anatomy, pathobiomechanics, diagnostics and therapy of syndesmosis lesions from an evidence-based viewpoint.

[Current treatment concepts for muscular injuries]. / Aktuelle Behandlungskonzepte bei Muskelverletzungen.

Muscular lesions represent the most common form of sports injury. The four large muscle groups hamstrings, adductors, gastrocnemius and knee extensor muscles are most often affected. Most injuries occur during excentric tension impact. Diagnostics begin with an exact medical history and detailed clinical investigations. Imaging with ultrasound and magnetic resonance imaging (MRI) are important to differentiate between structural lesions and functional disorders and to determine the extent of the injury. Most frequently treatment remains conservative and is oriented to the three phases of the healing process. In most cases (leisure sports) the rest, ice, compression and elevation (RICE) concept with subsequent pain-adapted load increase suffices for a return to sport activities. Infiltration therapy including platelet-rich plasma (PRP) is an additional therapy option but should not be used to accelerate the healing process. Surgical treatment only rarely becomes necessary for treatment of muscular injuries.

Immunocytochemical determination of the subcellular distribution of ascorbate in plants.

Ascorbate is an important antioxidant in plants and fulfills many functions related to plant defense, redox signaling and modulation of gene expression. We have analyzed the subcellular distribution of reduced and oxidized ascorbate in leaf cells of Arabidopsis thaliana and Nicotiana tabacum by high-resolution immuno electron microscopy. The accuracy and specificity of the applied method is supported by several observations. First, preadsorption of the ascorbate antisera with ascorbic acid or dehydroascorbic acid resulted in the reduction of the labeling to background levels. Second, the overall labeling density was reduced between 50 and 61% in the ascorbate-deficient Arabidopsis mutants vtc1-2 and vtc2-1, which correlated well with biochemical measurements. The highest ascorbate-specific labeling was detected in nuclei and the cytosol whereas the lowest levels were found in vacuoles. Intermediate labeling was observed in chloroplasts, mitochondria and peroxisomes. This method was used to determine the subcellular ascorbate distribution in leaf cells of plants exposed to high light intensity, a stress factor that is well known to cause an increase in cellular ascorbate concentration. High light intensities resulted in a strong increase in overall labeling density. Interestingly, the strongest compartment-specific increase was found in vacuoles (fourfold) and in plastids (twofold). Ascorbate-specific labeling was restricted to the matrix of mitochondria and to the stroma of chloroplasts in control plants but was also detected in the lumen of thylakoids after high light exposure. In summary, this study reveals an improved insight into the subcellular distribution of ascorbate in plants and the method can now be applied to determine compartment-specific changes in ascorbate in response to various stress situations.

Subcellular immunocytochemical analysis detects the highest concentrations of glutathione in mitochondria and not in plastids.

The tripeptide glutathione is a major antioxidant and redox buffer with multiple roles in plant metabolism. Glutathione biosynthesis is restricted to the cytosol and the plastids and the product is distributed to the various organelles by unknown mechanisms. In the present study immunogold cytochemistry based on anti-glutathione antisera and transmission electron microscopy was used to determine the relative concentration of glutathione in different organelles of Arabidopsis thaliana leaf and root cells. Glutathione-specific labelling was detected in all cellular compartments except the apoplast and the vacuole. The highest glutathione content was surprisingly not found in plastids, which have been described before as a major site of glutathione accumulation, but in mitochondria which lack the capacity for glutathione biosynthesis. Mitochondria of both leaf and root cells contained 7-fold and 4-fold, respectively, higher glutathione levels than plastids while the density of glutathione labelling in the cytosol, nuclei, and peroxisomes was intermediate. The accuracy of the glutathione labelling is supported by two observations. First, pre-adsorption of the anti-glutathione antisera with glutathione reduced the density of the gold particles in all organelles to background levels. Second, the overall glutathione-labelling density was reduced by about 90% in leaves of the glutathione-deficient Arabidopsis mutant pad2-1 and increased in transgenic plants with enhanced glutathione accumulation. Hence, there was a strong correlation between immunocytochemical and biochemical data of glutathione accumulation. Interestingly, the glutathione labelling of mitochondria in pad2-1 remained very similar to wild-type plants thus suggesting that the high mitochondrial glutathione content is maintained in a situation of permanent glutathione-deficiency at the expense of other glutathione pools. High and constant levels of glutathione in mitochondria appear to be particularly important in cell survival strategies and it is predicted that mitochondria must have highly competitive mitochondrial glutathione uptake systems. The present results underline the suggestion that subcellular glutathione concentrations are not controlled by a global mechanism but are controlled on an individual basis and it is therefore not possible to conclude from global biochemical glutathione analysis on the status of the various organellar pools.

Functional Implications of the Subcellular Localization of Ethylene-Induced Chitinase and [beta]-1,3-Glucanase in Bean Leaves.

Plants respond to an attack by potentially pathogenic organisms and to the plant stress hormone ethylene with an increased synthesis of hydrolases such as chitinase and [beta]-1,3-glucanase. We have studied the subcellular localization of these two enzymes in ethylene-treated bean leaves by immunogold cytochemistry and by biochemical fractionation techniques. Our micrographs indicate that chitinase and [beta]-1,3-glucanase accumulate in the vacuole of ethylene-treated leaf cells. Within the vacuole label was found predominantly over ethylene-induced electron dense protein aggregates. A second, minor site of accumulation of [beta]-1,3-glucanase was the cell wall, where label was present nearly exclusively over the middle lamella surrounding intercellular air spaces. Both kinds of antibodies labeled Golgi cisternae of ethylene-treated tissue, suggesting that the newly synthesized chitinase and [beta]-1,3-glucanase are processed in the Golgi apparatus. Biochemical fractionation studies confirmed the accumulation in high concentrations of both chitinase and [beta]-1,3-glucanase in isolated vacuoles, and demonstrated that only [beta]-1,3-glucanase, but not chitinase, was present in intercellular washing fluids collected from ethylene-treated leaves. Based on these results and earlier studies, we propose a model in which the vacuole-localized chitinase and [beta]-1,3-glucanase are used as a last line of defense to be released when the attacked host cells lyse. The cell wall-localized [beta]-1,3-glucanase, on the other hand, would be involved in recognition processes, releasing defense activating signaling molecules from the walls of invading pathogens.

Sequence and expression of a wheat gene that encodes a novel protein associated with pathogen defense.

Wheat (Triticum aestivum) exhibits local acquired resistance to the powdery mildew pathogen Erysiphe graminis f. sp. tritici. The resistant state can be induced by a preinoculation with the nonhost pathogen E. g.f. sp. hordei, the barley powdery mildew, and is accompanied by the activation of putative defense genes. Here, we report the sequence of a pathogen-induced gene, WIR1a, and a corresponding cDNA, WIR1, that encode novel defense-related proteins of 88 and 85 amino acids, respectively. Analysis of the primary structure of these proteins predicts them to be integral membrane proteins with extracytoplasmic C-terminal domains rich in proline and glycine, through which the proteins possibly interact with the cell wall.

A pathogen-induced wheat gene encodes a protein homologous to glutathione-S-transferases.

Winter wheat (Triticum aestivum) shows local, induced resistance against the plant-pathogenic fungus Erysiphe graminis f. sp. tritici following exposure to the nonpathogen E. g. f. sp. hordei. The onset of this resistance has been shown to be correlated with the activation of putative defense genes, and cDNA clones representing transcripts of induced genes have been obtained (P. Schweizer, W. Hunziker, and E. Mösinger, Plant Molecular Biology 12:643-654, 1989). We have cloned and sequenced a gene corresponding to one of these cDNAs, WIR5. Sequence analysis indicated that this gene contains three exons and encodes a protein of 229 amino acids. S1 mapping showed that transcripts homologous to this gene are at least 20 times more abundant in leaves infected 14 hr earlier with E. g. f. sp. hordei than in control leaves. Sequence comparison showed that the WIR5 gene product is highly homologous to glutathione-S-transferases (GSTs; EC 25.1.18) of maize. This, together with the fact that the intron positions of both the wheat gene and the maize GSTI gene are conserved, suggests that the cloned pathogen-induced gene, named GstA1, encodes a wheat glutathione-S-transferase.