iNClusive: a database collecting useful information on non-canonical amino acids and their incorporation into proteins for easier genetic code expansion implementation.

The incorporation of non-canonical amino acids (ncAAs) into proteins is a powerful technique used in various research fields. Genetic code expansion (GCE) is the most common way to achieve this: a specific codon is selected to be decoded by a dedicated tRNA orthogonal to the endogenous ones. In the past 30 years, great progress has been made to obtain novel tRNA synthetases (aaRSs) accepting a variety of ncAAs with distinct physicochemical properties, to develop robust in vitro assays or approaches for codon reassignment. This sparked the use of the technique, leading to the accumulation of publications, from which gathering all relevant information can appear daunting. Here we present iNClusive (https://non-canonical-aas.biologie.uni-freiburg.de/), a manually curated, extensive repository using standardized nomenclature that provides organized information on ncAAs successfully incorporated into target proteins as verified by mass spectrometry. Since we focused on tRNA synthetase-based tRNA loading, we provide the sequence of the tRNA and aaRS used for the incorporation. Derived from more than 687 peer-reviewed publications, it currently contains 2432 entries about 466 ncAAs, 569 protein targets, 500 aaRSs and 144 tRNAs. We foresee iNClusive will encourage more researchers to experiment with ncAA incorporation thus contributing to the further development of this exciting technique.

The tumor core boost study: A feasibility study of radical dose escalation to the central part of large tumors with an integrated boost in the palliative treatment setting.

PURPOSE: For patients with large tumors palliative radiotherapy often is the only local treatment option. To prevent toxicity the administered doses are low. Dose escalation to the tumor could be an option to better smyptom control and prolong local control rates. In this prospective study we used a very pragmatic approach with a simultaneously integrated boost (SIB) to an almost geometrically defined tumor core to achieve this. The primary endpoint was to demonstrate feasibility. METHOD: Patients with solid tumors > 4 cm in diameter of different histologies were eligible in this single arm, prospective, multi-institutional clinical feasibility trial with two treatment concepts: 5â€¯× 5 Gy with an integrated boost to the tumor core of 5â€¯× 10 Gy or 10â€¯× 3 Gy with a boost of 10â€¯× 6 Gy. The objective of dose escalation in this study was to deliver a minimum dose of 150% of the prescribed dose to the gross tumor volume (GTV) tumor core and to reach a maximum of at least 200% in the tumor core. RESULTS: In all, 21 patients at three study sites were recruited between January 2019 and November 2020 and were almost evenly spread (9 to 12) between the two concepts. The treated planning target volumes (PTV) averaged 389.42 cm3 (range 49.4-1179.6 cm3). The corresponding core volumes were 72.85 cm3 on average (range 4.21-338.3 cm3). Dose escalation to the tumor core with mean doses of 167.7-207.7% related to the nonboost prescribed isodose led to PTV mean doses of 120.5-163.3%. Treatment delivery and short-term follow-up was successful in all patients. CONCLUSIONS: Palliative radiotherapy with SIB to the tumor core seems to be a feasible and well-tolerated treatment concept for large tumors. The applied high doses of up to 50 Gy in 5 fractions (or 60 Gy in 10 fractions) did not cause unexpected side effects in the 42 day follow-up period. Further research is needed for more information on efficacy and long-term toxicity.

Quo vadis, foot & ankle research? A review.

Over the last two decades, there has been a growing emphasis on the publication quality in Foot & Ankle research. A level-of-evidence rating system for clinical scientific papers has been proposed by the Centre for Evidence-based medicine in Oxford, United Kingdom. As opposed to other subspecialities, foot & ankle surgery deals with a wide variety of clinical problems and surgical solutions, which in turn leads to a generally low number of patients available for study groups. However, level III and IV studies still have a valuable place in orthopaedic research, given the challenges in running high-level studies.The measurement of outcomes in medicine from the patients' perspective (PROMS:(patient reported outcome measures) has grown almost exponentially in all surgical specialties including foot & ankle surgery. There are many PROMs available to foot & ankle surgeons, but there is little consensus on which assessment is most appropriate for a given procedure or diagnosis. Their use in research and clinical practice offers many advantages in clinical practice and research, however, besides the advantages there are also some downsides.

Evaluation of Radiographic Features Including Metatarsus Primus Elevatus in Hallux Rigidus.

The etiology of hallux rigidus remains a controversial issue in foot and ankle surgery, i.e., the relationship between metatarsus primus elevatus (MPE) and hallux rigidus. The purpose of this study was to evaluate several radiographic parameters including first metatarsal elevation in patients with hallux rigidus compared to a matched control group. A retrospective case control study was performed including 50 feet, 25 feet with and 25 feet without hallux rigidus. In the patients with hallux rigidus, the first metatarsal was more elevated than in the control group (8.3 ± 1.7 mm vs 3.0 ± 2.0 mm, p < .001) and in 60% of patients with hallux rigidus MPE was diagnosed, compared to zero patients in the control group (p < .001). The lateral 1 to 2 intermetatarsal angle was higher in patients with hallux rigidus (3.6 ± 2.5 vs -0.7 ± 2.8; p < .001). The first metatarsal declination angle was not different between the 2 groups. Intraclass correlation coefficient between 2 observers for measuring the first metatarsal elevation was 0.929 (p < .001). In the current study, increased elevation of the first metatarsal, a higher incidence of MPE and increased lateral 1 to 2 intermetatarsal angle were found in patients with hallux rigidus compared to the control group. These findings support the theory of an association between MPE and hallux rigidus. Further high reliability of first metatarsal elevation measurement was found in our study.

[Malleolar Fractures - Indication for Nonoperative and Operative Treatment]. / Malleolarfrakturen.

Malleolar Fractures - Indication for Nonoperative and Operative Treatment Abstract. In order to understand the trauma mechanism and the expected pattern of injury, malleolar fractures can be classified according to Lauge-Hansen [1]. For isolated lateral malleolar fractures, the Weber classification is also frequently used [2]. For most Weber A fractures and 80% of Weber B fractures conservative treatment is indicated. In all isolated Weber B fractures a supination-external rotation (SER) injury has to be distinguished from a pronation-abduction (PA) injury according to the Lauge-Hansen classification. In SER fractures, stability should be assessed by a gravity stress and a weightbearing radiograph. If the fracture is stable, it can be treated nonoperatively. We recommend surgical treatment for unstable Weber B SER injuries, Weber B PA injuries, and Weber C fractures.

Spinopelvic dissociation in patients suffering injuries from airborne sports.

BACKGROUND: Spinopelvic dissociation which is also called U-type or referred to H-type sacral fractures with a transverse fracture line is an infrequent injury that results mainly from high-energy accidents. This results in an osseous dissociation of the upper central segment of the sacrum and the entire spine from the lower sacral segments. The purpose was to investigate the incidence of spinopelvic fracture in general among airborne injuries. PATIENTS AND METHODS: Using our electronic patient records, we retrospectively investigated all sacral fractures related to airborne sports between 2010 and 2017. All injuries were classified according to the Roy-Camille, Denis, AOSpine and the Tile classification system. RESULTS: During the period of interest, 44 patients (18.7%) were admitted with sacral fractures after accidents obtained from airborne sports, including 16 spinopelvic dissociations (36.4%). The majority of these injuries were obtained from paragliding (75.0%), followed by BASE jumping (21.4%) and parachuting (4%). The mean injury severity score (ISS) in the spinopelvic dissociation group was significantly higher compared with other sacral fracture group (38.1 vs. 20.0; p < 0.001). Six lambda-type, four T-type, four H-type and two U-type injuries were identified. In total, four patients (25%) were found to have neurological impairment. For treatment, 87.5% of patients underwent subsequent surgical stabilization. CONCLUSION: Airborne sports have high potential for serious, life-threatening injuries with a high incidence of spinopelvic dissociation. In the literature, the prevalence of spinopelvic dissociation in sacral fractures is described to be between 3 and 5%. In our series, the prevalence is 36.4%. It is important to identify the potential injuries promptly for the further treatment. These slides can be retrieved under Electronic Supplementary Material.

Spinal injuries in airborne accidents: a demographic overview of 148 patients in a level-1 trauma center.

PURPOSE: The purpose of this study was to investigate the type and severity of spinal injury in airborne sports, as well as patients demographics in this unique set of athletes. Paragliding is one of the most popular airborne sports in Switzerland, which thought to be no less dangerous with a high potential for spinal injury. Few studies on spinal column injuries have been performed in these high-risk athletes with only inconsistent findings. METHODS: Patient charts were analyzed for all airborne sports injuries affecting the spine from 2010 to 2017 at a level-1 trauma center in Switzerland. To classify the injuries, we used the newest AOSpine classification, ASIA-grading and the injury severity score (ISS). In total, 235 patients were admitted to the emergency department due to an airborne injury. A total of 148 patients (148/235, 63.0%) which were predominantly male (125/235, 84.5%) at a mean age of 39.4 years suffered 334 spinal fractures and 5 spinal contusions. The mean ISS was 17.3, and the L1 vertebra was most commonly affected (47.6% of cases, 68/148). RESULTS: A total of 78 patients (54.5% or 78/148) required spine surgery due to instability or neurological deficits (31/148 patients; 20.9%). Concomitant injuries were identified in 64.2% of cases (n = 95). CONCLUSION: Due to the increasing popularity of airborne sports, age of patients and severity of injuries (ISS) increased compared with the literature. The thoracolumbal spine is at especially high risk. To prevent further complications, the treatment procedure has to be sought carefully and algorithm should be introduced in clinics to avoid delay in diagnostics and surgery. LEVEL OF EVIDENCE: III, retrospective comparative study. These slides can be retrieved under Electronic Supplementary Material.

Oligometastases in prostate cancer : Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT.

BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSMA PET/CTs after hypofractionated IGRT for metastatic lesions are reported here. MATERIALS AND METHODS: Of 280 patients investigated with 68Ga-PSMA PET/CT in the period from 01/2014 through 12/2016 in the authors' department, patients were selected according to the following criteria: oligometastatic disease at initial PSMA PET/CT defined as not more than five metastatic lesions, hypofractionated IGRT to all lesions, no systemic therapy in the last 6 months and during follow-up, and at least one follow-up PSMA PET after radiotherapy. Radiotherapy was administered to all PSMA PET-detected lesions (CTV = PET-GTV + 1 to 2 mm), mostly with 35 Gy in five fractions (one lesion with four fractions of 7 Gy due to dose constraints, two lymph nodes with 50 Gy in 25 fractions to an extended volume plus a boost of 7 Gy × 2 to the PET-positive volume). Metabolic response of irradiated lesions was evaluated on repeated PSMA PET/CTs according to PERCIST criteria. Five patients with a total number of 12 PSMA PETs matched the criteria. Patients received radiotherapy to all PET-positive lesions and had at least one (in one case three) follow-up PSMA PET examinations after radiotherapy with an interval to the first PET of 2-15 months; the median follow-up for all patients was 11 months. RESULTS: The mean prostate-specific antigen (PSA) values at the time of examination were 8.9 ± 8.5 ng/ml (median 3.3 ng/ml, range 0.17-21.8 ng/ml). A total number of 18 metastatic deposits were detected. The PET-positive tumor volume was 5.9 ± 13.3 cm3 (median 1.25 cm3). The mean standardized uptake value (mean SUVmax) of the 18 metastatic lesions decreased from 19.9 ± 23.3 (mean ± SD) prior to RT to 5.4 ± 4.6 at post-radiotherapy PSMA PET/CT. Using PERCIST criteria, 14 lesions (78%) showed a metabolic response in PSMA PET with a reduction of SUV of at least 30%, as well as a significant decrease in lesion size; in seven of these lesions, no uptake of 68Ga-PSMA was detectable. In follow-up PET scans, only two lesions showed metabolic progression with an increase in SUVmax yielding a local progression-free survival of 88% after 1 year. There was a correlation between the time interval after radiotherapy (median 3 months, range 1-9 months) and response (p = 0.04) with better metabolic response after longer follow-up. CONCLUSIONS: Preliminary results of this study show high metabolic response rates of PSMA PET-positive metastatic lesions after hypofractionated radiotherapy in follow-up PSMA PET with promising local control rates. An interval of several months may be required to fully estimate the efficacy of radiotherapy in control PSMA PET.

Isolated Rupture of the Distal Plantaris Muscle.

In the present case, the plantaris tendon was ruptured in isolation and at the distal part of the tendon. An injury of the Achilles tendon, gastrocnemius muscle, or soleus muscle was not detected. To the best of our knowledge, a similar case has not yet been reported. Our case basically demonstrates that a rupture of the musculus plantaris does not have to occur at the myotendiouns junction or the muscle belly itself. The initial nonoperative treatment with physiotherapy, antiinflammatory medicine, and an early return to sports, even for this more distal plantaris tendon rupture, led to a good result.

Quality of Early Union After First Metatarsophalangeal Joint Arthrodesis.

The aim of the present retrospective cohort study was to assess the quality of union and the clinical outcomes in patients who had undergone first metatarsophalangeal joint (MTPJ) fusion using a dorsal plate and plantar lag screw. From March 2011 to December 2012, the clinical and radiographic data of 39 patients (41 feet) who had undergone first MTPJ fusion using a compressive locking plate were retrospectively reviewed. All patients had undergone postoperative computed tomography at 6 weeks postoperatively to assess union. The average metatarsophalangeal angles improved from 23° ± 16° preoperatively to 14° ± 5° postoperatively. The dorsiflexion of the hallux at the preoperative assessment averaged 17° ± 11° and 23° ± 5° postoperatively. At 6 weeks postoperatively, the computed tomography scans demonstrated 3 complete fusions (7.3 %) and 38 partial unions (92.7%). Also at 6 weeks, the mean ± standard deviation joint bridging was 54% ± 14.6%. The forefoot American Orthopaedic Foot and Ankle Society scale score had improved significantly from 50 ± 13 preoperatively to 80 ± 7 at >1 year of follow-up (p = .001). Hardware removal was performed in 8 cases because of pain in 7 and infection in 1. Revision arthrodesis was required in 2 cases because of nonunion. At 6 weeks postoperatively, partial bony joint bridging could be observed in most cases after arthrodesis of the first MTPJ with the dorsal fusion plate.

Post-operative monitoring of free muscle transfers by Laser Doppler Imaging: A prospective study.

PURPOSE: Despite different existing methods, monitoring of free muscle transfer is still challenging. In the current study we evaluated our clinical setting regarding monitoring of such tissues, using a recent microcirculation-imaging camera (EasyLDI) as an additional tool for detection of perfusion incompetency. PATIENTS AND METHODS: This study was performed on seven patients with soft tissue defect, who underwent reconstruction with free gracilis muscle. Beside standard monitoring protocol (clinical assessment, temperature strips, and surface Doppler), hourly EasyLDI monitoring was performed for 48 hours. Thereby a baseline value (raised flap but connected to its vascular bundle) and an ischaemia perfusion value (completely resected flap) were measured at the same point. RESULTS: The mean age of the patients, mean baseline value, ischaemia value perfusion were 48.00 ± 13.42 years, 49.31 ± 17.33 arbitrary perfusion units (APU), 9.87 ± 4.22 APU, respectively. The LDI measured values in six free muscle transfers were compatible with hourly standard monitoring protocol, and normalized LDI values significantly increased during time (P < 0.001, r = 0.412). One of the flaps required a return to theatre 17 hours after the operation, where an unsalvageable flap loss was detected. All normalized LDI values of this flap were under the ischaemia perfusion level and the trend was significantly descending during time (P < 0.001, r = -0.870). CONCLUSION: Due to the capability of early detection of perfusion incompetency, LDI may be recommended as an additional post-operative monitoring device for free muscle flaps, for early detection of suspected failing flaps and for validation of other methods.

Biomechanical Effects of Hindfoot Alignment in Supination External Rotation Malleolar Fractures: A Human Cadaveric Model.

BACKGROUND: Pressure distribution in the ankle joint is known to be dependent on various factors, including hindfoot alignment. We seek to evaluate how hindfoot alignment affects contact pressures in the ankle joint in the setting of supination external rotation (SER) type ankle fractures. METHODS: SER fractures were created in 10 human cadaver lower extremity specimens, simulating progressive stages of injury: without fracture (step 0), SER fracture and intact deltoid ligament (step 1), superficial deltoid ligament disruption (step 2), and deep deltoid ligament disruption (step 3). At each step, varus and valgus alignment was simulated by displacing the calcaneal tuberosity 7 mm medial or lateral. Each limb was axially loaded following each osteotomy at a static load of 350 N. The center of force (COF), contact area (CA), and peak contact pressure (PP) under load were measured, and radiographs of the ankle mortise were taken to analyze the medial clear space (MCS) and talar tilt (TT). RESULTS: The COF (5.3 mm, P = .030) and the CA (-188.4 mm2, P = .015) changed in step 3 in the valgus hindfoot alignment compared to baseline parameters, indicating the importance of deep deltoid ligament integrity in maintaining normal ankle joint contact stress in the valgus hindfoot. These changes were not seen in the setting of varus alignment (COF: 2.3 mm, P = .059; CA -121 mm2, P = .133). PP were found to not change significantly in either varus or valgus (varus: -4.9 N, P = .132; valgus: -4 N, P = .464).The MCS demonstrated widening in step 3 compared to step 2 (0.7 mm, P = .020) in both varus and valgus hindfoot. The TT increased significantly in step 3 in the valgus hindfoot (2.8 degrees, P = .020) compared to step 0. CONCLUSION: SER-IV fractures with valgus hindfoot alignment showed significant changes in pressure distribution and radiographic parameters when compared to SER-IV fractures with varus hindfoot alignment. CLINICAL RELEVANCE: Based on this cadaver modeling study, patients with SERIV fracture with varus hindfoot alignment and complete deltoid ligament lesion may not need fracture fixation, whereas those with valgus hindfoot alignment likely need fracture fixation.

Cavovarus foot realignment to treat anteromedial ankle arthrosis.

BACKGROUND: Adult patients with cavovarus feet were seen with symptomatic anteromedial ankle arthrosis and, frequently, lateral hindfoot instability. Static and dynamic realignment was performed to redistribute joint contact pressures and restore stability. METHODS: Thirteen patients with fixed cavovarus feet (6 neurogenic, 7 idiopathic; 6 with hindfoot instability, 7 without) and mild to moderate anteromedial ankle arthrosis were treated by osteotomies and tendon transfers but no lateral ligament reconstruction. Anteromedial cheilectomy of the ankle was added to increase dorsiflexion and alleviate anteromedial impingement. RESULTS: Failure occurred in 2 patients, who required additional procedures. The remaining 11 patients improved from preoperative 45 to 71 points (American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale score) at the latest follow-up (average 84 months). Ankle dorsiflexion improved 7 degrees on average. There was no recurrent hindfoot instability and no progression of anteromedial ankle arthrosis over time. CONCLUSION: Cavovarus foot realignment with anteromedial ankle cheilectomy reliably improved patients' symptoms related to ankle arthrosis, restored lateral hindfoot stability, and stabilized the extent of anteromedial ankle arthrosis when talar varus tilt was reduced. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Ankle joint pressure changes in a pes cavovarus model: supramalleolar valgus osteotomy versus lateralizing calcaneal osteotomy.

BACKGROUND: A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared. METHODS: A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors. RESULTS: A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen. CONCLUSION: LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was seen. CLINICAL RELEVANCE: In patients with fixed cavovarus feet, both SMOT and LCOT provided equally good redistribution of elevated ankle joint contact forces. Increasing the amount of displacement did not seem to equally improve the joint pressures. The site of osteotomy could therefore be chosen on the basis of surgeon's preference, simplicity, or local factors in case of more complex reconstructions.

Risk Factors for Failure After Surgery in Patients With Diabetic Foot Syndrome.

Background: In the present study, we aimed to identify risk factors for failure (defined as reoperation within 60 days) after debridement or amputation at the lower extremity in patients with diabetic foot syndrome and to develop a model using the significant risk factors to predict the success rate at different levels of amputation. Methods: Between September 2012 and November 2016, we performed a prospective observational cohort study of 174 surgeries in 105 patients with diabetic foot syndrome. In all patients, debridement or the level of amputation, need for reoperation, time to reoperation, and potential risk factors were assessed. A cox regression analysis, dependent on the level of amputation, with the endpoint reoperation within 60 days defined as failure and a predictive model for the significant risk factors were conducted. Results: We identified the following 5 independent risk factors: More than 1 ulcer (hazard ratio [HR] 3.8), peripheral artery disease (PAD, HR 3.1), C-reactive protein >100 mg/L (HR 2.9), diabetic peripheral neuropathy (HR 2.9), and nonpalpable foot pulses (HR 2.7) are the 5 independent risk factors for failure, which were identified. Patients with no or 1 risk factor have a high success rate independent of the level of amputation. A patient with up to 2 risk factors undergoing debridement will achieve a success rate of <60%. However, a patient with 3 risk factors undergoing debridement will need further surgery in >80%. In patients with 4 risk factors a transmetatarsal amputation and in patients with 5 risk factors a lower leg amputation is needed for a success rate >50%. Conclusion: Reoperation for diabetic foot syndrome occurs in 1 of 4 patients. Risk factors include presence of more than 1 ulcer, PAD, CRP > 100, peripheral neuropathy, and nonpalpable foot pulses. The more risk factors are present, the lower the success rate at a certain level of amputation. Level of Evidence: Level II, prospective observational cohort study.

ReverseDock: a web server for blind docking of a single ligand to multiple protein targets using AutoDock Vina.

Several platforms exist to perform molecular docking to computationally predict binders to a specific protein target from a library of ligands. The reverse, that is, docking a single ligand to various protein targets, can currently be done by very few web servers, which limits the search to a small set of pre-selected human proteins. However, the possibility to in silico predict which targets a compound identified in a high-throughput drug screen bind would help optimize and reduce the costs of the experimental workflow needed to reveal the molecular mechanism of action of a ligand. Here, we present ReverseDock, a blind docking web server based on AutoDock Vina specifically designed to allow users with no computational expertise to dock a ligand to 100 protein structures of their choice. ReverseDock increases the number and type of proteins a ligand can be docked to, making the task of in silico docking of a ligand to entire families of proteins straightforward. We envision ReverseDock will support researchers by providing the possibility to apply inverse docking computations using web browser. ReverseDock is available at: https://reversedock.biologie.uni-freiburg.de/.

Axial T2 mapping in intervertebral discs: a new technique for assessment of intervertebral disc degeneration.

OBJECTIVES: To demonstrate the potential benefits of biochemical axial T2 mapping of intervertebral discs (IVDs) regarding the detection and grading of early stages of degenerative disc disease using 1.5-Tesla magnetic resonance imaging (MRI) in a clinical setting. METHODS: Ninety-three patients suffering from lumbar spine problems were examined using standard MRI protocols including an axial T2 mapping protocol. All discs were classified morphologically and grouped as "healthy" or "abnormal". Differences between groups were analysed regarding to the specific T2 pattern at different regions of interest (ROIs). RESULTS: Healthy intervertebral discs revealed a distinct cross-sectional T2 value profile: T2 values were significantly lower in the annulus fibrosus compared with the nucleus pulposus (P = 0.01). In abnormal IVDs, T2 values were significantly lower, especially towards the centre of the disc representing the expected decreased water content of the nucleus (P = 0.01). In herniated discs, ROIs within the nucleus pulposus and ROIs covering the annulus fibrosus showed decreased T2 values. CONCLUSIONS: Axial T2 mapping is effective to detect early stages of degenerative disc disease. There is a potential benefit of axial T2 mapping as a diagnostic tool, allowing the quantitative assessment of intervertebral disc degeneration.

Underneath the cerclage: an ex vivo study on the cerclage-bone interface mechanics.

INTRODUCTION: Cerclages regain interest due to a rising number of periprosthetic fractures. The contact distribution at the circumferential cerclage-bone interface is still unknown. Local interface pressure depends on the amount of contact area. Cortical damage at the interface would provoke cerclage loosening. Therefore, the contact area, the bone pressure along the interface and the cortical resistance underneath loaded cerclages were determined in an ex vivo model. MATERIALS AND METHODS: Human diaphyseal femoral bone was used with differing cross-sectional geometry. Bone contact points of fixed 1.5 mm wire and 1.7 mm cable cerclages were identified from axial radiographs. Pressure distribution at the cerclage-bone interface was recorded with a pressure-measuring film using a distraction setup with two cortical half shells. Bone shells with installed cerclages were separated with up to 400 N force and were subsequently analyzed histologically to detect cortical damage. RESULTS: Both cerclage types exhibited a point contact fixation with non-loaded spanned zones in-between. Cables cover larger contact areas. Both cerclages exhibited an inhomogeneous interface pressure distribution depending on the bone surface geometry. Histology revealed intact cortical bone without cortical affection after loading of both cerclage types. CONCLUSION: Point contact fixation of the cerclages installs non-loaded, spanned zones where the periosteum is not compressed, rendering a strangulation of the blood supply unlikely. Cortical bone withstands static concentric pressure produced by the cerclage. Cortical groove formation is attributed to instability under functional load and not to weakness of the cortex itself.

Osteochondral lesion of the talus: still a problem?

Osteochondral lesion of the talus (OLT) often occurs after ankle trauma or repetitive micro-traumata, whereas the actual etiology remains unclear. The most common symptoms are local pain deep in the medial or lateral ankle that increases with weight-bearing and activity, accompanied by tenderness and swelling. Eventually, most patients with symptomatic or unstable OLT require surgery. Many reasonable operative techniques have been described, whereas most lead to similar and satisfactory results. They can be divided into cartilage repair, cartilage regeneration and cartilage replacement techniques. The OLT size and morphology in the first place but also surgeon and individual patient aspects are considered when it comes to surgery. For high postoperative success and low recurrence rates, underlying causes, for example, ligamentous instability and hindfoot malalignment should also be addressed during surgery.