Main Fracture Lines Research Articles

The infraacetabular screw versus the antegrade posterior column screw in acetabulum fractures with posterior column involvement: a biomechanical comparison

IntroductionTraditionally, plate osteosynthesis of the anterior column combined with an antegrade posterior column screw is used for fixation of anterior column plus posterior hemitransverse (ACPHT) acetabulum fractures. Replacing the posterior column screw with an infraacetabular screw could improve the straightforwardness of acetabulum surgery, as it can be inserted using less invasive approaches, such as the AIP/Stoppa approach, which is a well-established standard approach. However, the biomechanical stability of a plate osteosynthesis combined with an infraacetabular screw instead of an antegrade posterior column screw is unknown.Material and methodsTwo osteosynthesis constructs were compared in a synthetic hemipelvis model with an ACPHT fracture: Suprapectineal plate + antegrade posterior column screw (APCS group) vs. suprapectineal plate + infraacetabular screw (IAS group). A single-leg stance test protocol with an additional passive muscle force and a cyclic loading of 32,000 cycles with a maximum effective load of 2400 N was applied. Interfragmentary motion and rotation of the three main fracture lines were measured.ResultsAt the posterior hemitransverse fracture line, interfragmentary motion perpendicular to the fracture line (p < 0.001) and shear motion (p < 0.001) and at the high anterior column fracture line, interfragmentary motion longitudinal to the fracture line (p = 0.017) were significantly higher in the IAS group than in the APCS group. On the other hand, interfragmentary motion perpendicular (p = 0.004), longitudinal (p < 0.001) and horizontal to the fracture line (p = 0.004) and shear motion (p < 0.001) were significantly increased at the low anterior column fracture line in the APCS group compared to the IAS group.ConclusionsReplacing the antegrade posterior column screw with an infraacetabular screw is not recommendable as it results in an increased interfragmentary motion, especially at the posterior hemitransverse component of an ACPHT fracture.

Analysis of Potential Risk Factors for Cement Leakage into Paraspinal Veins after Vertebroplasty for Acute Osteoporotic Vertebral Fractures Based on a 3D Reconstruction Technique: A Retrospective Matched Case-Control Study.

Pulmonary embolism, cardiac embolism, and even cerebral embolism due to paraspinal vein leakage (PVL) are increasingly reported, and their risk factors need to be adequately investigated for prevention. To this end, this study investigated the correlation of the distribution and morphological characteristics of fracture lines with the occurrence of PVL after percutaneous vertebroplasty (PVP), which has not been previously reported. Patients with acute single-segment thoracolumbar osteoporotic vertebral compression fractures (OVCFs) treated with PVP at our institution from January 2019 to July 2022 were selected for a matched case-control study. The case and control groups included those with and without PVL, respectively, matched at a 1:1 ratio based on general clinical characteristics. Additionally, fracture map and heatmap analysis was performed in both groups. In addition to the general clinical characteristics, the vertebral height ratio, puncture angle, delivery rate, and indexes were assessed via the three-dimensional CT reconstruction fracture line mapping technique, namely, the distribution of fracture lines, fracture line length, main fracture line shape, location of fracture line involvement, and number of fracture line branches, were compared between the two groups. The Wilcoxon rank-sum test, t tests, analysis of variance, and conditional logistic regression were used for statistical analysis. Among 658 patients with OVCFs, 54 who did and 54 who did not develop PVL were included in this study. Significant differences in the puncture angle, fracture line distribution (MR-1, ML-2, MM-2, MR-2, ML-3, MM-3, LL-1, LM-1, LL-2, LM-2), fracture line involvement of the posterior wall, total fracture line length, and main fracture line length were found between the two groups (p < 0.05). Logistic univariate analysis showed significant differences in the puncture angle, fracture line distribution (MR-1, ML-2, MM-2, MR-2, ML-3, MM-3, LL-1, LL-2, LM-2, LL-3), total fracture line length, main fracture line length, and fracture line involvement of the posterior wall between the two groups (p < 0.05). Logistic multifactorial analysis showed that the fracture line distribution (UR-3, ML-3, LM-2, LR-2) and main fracture line length were independent risk factors for the development of PVL in both groups. In addition, the fracture maps and heatmaps showed a greater degree of fracture line encapsulation and more extensive involvement in the middle and lower regions of the vertebral body in the PVL group than in the control group. Through a three-dimensional computed tomography reconstruction-based fracture line mapping technique, this study revealed for the first time that the distribution of fracture lines (UR-3, ML-3, LM-2, LR-2) and main fracture line length were independent risk factors for PVL after PVP in patients with acute single-segment thoracolumbar OVCFs. In addition, we hypothesized that the fracture line-vein traffic branch that may appear within 2 weeks after injury in acute OVCF patients may be one of the mechanisms influencing the above potential independent risk factors associated with PVL.

Proximal fracture line extension in humeral shaft fractures

IntroductionHumeral shaft fractures are common injuries treated by orthopaedic surgeons. The purpose of this study is to evaluate displaced diaphyseal humerus fractures and describe the incidence and characteristics associated with non or minimally displaced fracture line extension into the proximal metadiaphyseal region of the humerus. Methods and materialsAll adult patients with diaphyseal humeral shaft fractures located within the distal two-thirds of the humeral shaft, treated at a single level I trauma institution between 2007 and 2020, were retrospectively identified. 202 patients with 203 fractures of the humeral shaft were included. Fracture patterns were classified according to AO/OTA classification and fracture line extension into the proximal metadiaphyseal region was evaluated on radiographs. Patient demographics, management details, and radiographic outcomes were obtained from review of the electronic medical record. ResultsOf 203 diaphyseal humerus fractures, 11.8 % (n = 24) had non or minimally displaced proximal extension of their main fracture line. This included 43.7 % (n = 7) of all proximal third junction diaphyseal fractures, 10.7 % (n = 16) of all middle third diaphyseal fractures, and 2.6 % (n = 1) of all distal third diaphyseal fractures. Patients with proximal fracture extension were, on average, older (61.7 versus 44.4 years, p < 0.001), and a higher percentage were female (75 % versus 45.5 %, p < 0.01) compared to patients without fracture proximal extension. Fractures with proximal extension were all closed fractures (n = 24), were more often sustained from low-energy fall (87.5 % versus 35.2 %, p < 0.001), and were more often spiral type fractures (62.5 % versus 17.2 %). Fractures with proximal extension were more often treated non-operatively (58.3 % versus 42.1 %, p < 0.01), but were found to have a higher rate of nonunion after non-operative treatment (17.6 % versus 8.1 %) compared to fractures without proximal extension. All operatively treated fractures that had proximal metaphyseal extension were secured with a fixation construct to achieve fixation proximal to the extent of the fracture line, most often into the humeral head and neck. Operative management with proximal fixation into the humeral head was also pursued for a patient with nonunion, including persistent lucency of the proximal extension line, after failed non-operative treatment. Mean follow-up was 35.5 weeks (range: 0–607 weeks). ConclusionsProximal fracture line extension in the setting of diaphyseal humerus fractures is not uncommon. Detection and consideration of this sometimes subtle finding is important when planning to treat these injuries operatively.

Morphological Features and Clinical Results of C2 Vertebral Body Fractures

Type of study: Retrospective study. Objectives: To classify and analyze the morphological patterns of vertebral body fractures and report the clinical results. Summary of literature review: There have not been many reports on the classification of vertebral body fractures and treatment results, and it remains a matter of debate. Materials and methods: Among 107 patients diagnosed with an axis fracture from 2005 to 2019, 53 patients with fracture involving the vertebral body were selected. After the exclusion of 9 patients with a history of cervical spine surgery or who were lost to follow-up, 44 consecutive patients were enrolled in this retrospective study. Patients were classified into 5 groups (coronal, sagittal, transverse, avulsion, and complex) according to the main fracture line. The demographic data, injury mechanism, discoligamentous injury, combined injury, neurological symptoms, and clinical treatment results were analyzed. Results: Patients’ average age was 61.7 years (range, 25–81 years). 24 patients were male and 20 were female. The average follow-up period was 14.2 months (range, 7–33 months). The coronal, sagittal, transverse, avulsion, and complex groups contained 5, 5,8, 7, and 19 patients, respectively. Six patients were injured by slip-down accidents, 12 patients by falling height, and 26 patients by traffic accidents. Eighteen patients were presented with a discoligamentous injury. Twenty-five patients showed a combination of fractures of cervical vertebrae and bones. Thirteen patients presented neurological symptoms. 16 patients were treated with a neck collar and 28 patients were treated with a halo-vest. Two patients eventually required surgical fusion because union was not achieved with conservative management. In the final follow-up, all neurological symptoms were resolved; however, 4 patients still complained of a mild tingling sensation in the upper extremity. Pin site infection occurred in 3 patients who were treated with a halo-vest, but it was controlled after antibiotic administration. Conclusion: Vertebral body fractures accounted for almost 50% of axis fractures in this study. Vertebral body fractures can be classified into 5 groups (coronal, sagittal, transverse, avulsion, and complex) according to the morphological pattern. Non-operative management can be a reasonable treatment option with good clinical results and bone union.

Pathoanatomy of pertrochanteric fractures - a postmortem study

BackgroundRecent pathoanatomic studies based on 3D CT reconstructions have questioned validity of AO/OTA classification because it does not reflect the reality and requires revision. These 3D CT studies, however, do not allow analysis of all details. Therefore, we have exploited the possibility to analyze the pathoanatomy of pertrochanteric fractures on postmortem specimens. Material and methodsFrom the collection of the Institute of Anatomy, the authors obtained 16 specimens of hip joints of individuals who had sustained a pertrochanteric fracture and died within 30 days of the injury, with anteroposterior radiographs of the injured hip available in all of them. The number of major fragments and their shape, and the courses of the main fracture lines were studied. ResultsThree major fragments (a proximal head and neck fragment, a distal diaphyseal fragment and a posterior flat fragment), separated by three types of fracture lines (primary, secondary and tertiary lines) were identified. The primary line separated the proximal fragment (head and neck) from the distal diaphyseal fragment. The secondary fracture line separated the posterior flat fragment from the distal diaphyseal fragment. The tertiary fracture line split the posterior fragment into two parts. A key factor for fracture instability is the defect of the posterior cortex, which depends on the size and shape of the posterior fragment. Avulsion of the lesser trochanter and the adjacent cortex results in an unstable configuration of fracture lines on the medial side, while on the lateral side a large posterior fragment weakens the lateral trochanteric wall. ConclusionIn agreement with recent CT studies, the findings of this pathoanatomical study change, in a number of aspects, the traditional view of the pathoanatomy and classification of pertrochanteric fractures, and introduces the concept of three, instead of the traditional four, main fragments.

New Classification for Periprosthetic Distal Femoral Fractures Based on Locked-Plate Fixation Following Total Knee Arthroplasty: A Multicenter Study.

This study aimed to establish a new classification using locked-plate fixation for periprosthetic distal femoral fracture (PDFF) following total knee arthroplasty (TKA) and to determine when dual locked-plate fixation is necessary through defining this classification. One-hundred fifteen consecutive PDFFs that underwent operative treatment were reviewed from 2011 to 2019 with minimum 1-year follow-up. Most PDFFs were fixed with single or dual locked-plate fixations using the minimally invasive plate osteosynthesis technique. Based on preoperative radiographs, PDFFs were classified according to the level of main fracture line relative to the anterior flange of femoral component: type I and II, main fracture line located proximal and distal to the anterior flange; and type III, component instability regardless of fracture line requiring revisional TKA. Furthermore, type II fractures were subclassified based on the direction of fracture beak as follows: type IIL, lateral-beak; type IIM, medial-beak. The incidence, treatment methods, and complications were analyzed according to the classification. Incidences of type I, IIL, IIM, and III were 64.4%, 8.7%, 24.3%, and 2.6%, respectively. Meanwhile, most PDFFs in type I and II were treated with lateral single locked-plate fixations, except for type IIM, which was treated with either single or dual locked-plate fixations. Overall complications were significantly higher in type II (28.9%) than in type I (10.8%, P= .019). In type IIM, bone union-related complications were significantly higher in single locked-plate fixation (50.0%) than in dual locked-plate fixation (5.6%; P= .013). The new classification provides practical and obvious strategies for the treatment of PDFF following TKA using locked-plate fixation. For type IIM fracture, dual plate fixation is necessary to prevent fixation failure or nonunion.

Fracture Mapping of Both-Column Acetabular Fractures.

To characterize the location and frequency of the fracture lines and comminution zones of both-column fractures using fracture mapping. Both-column fractures were retrospectively reviewed in 4 Level 1 trauma centers. Mimics software was used to reconstruct the both-column fractures and simulate the fracture reduction. Then, the fracture lines and the intra-articular and extra-articular comminution zones were drawn on a 3-dimensional innominate bone template. The distribution of fracture lines and fracture fragments were also mapped on the two-dimensional template of the acetabulum. All the included patients were divided into low-variety group and high-variety group according to the anterior column fracture line above or below the anterior superior spine. The anatomical characteristics of the posterior wall fragment were also analyzed in these 2 groups. Seventy-eight patients with both-column fracture were included. The T type or inverted Y type main fracture lines divided the innominate bone into low-variety (n = 11) and high-variety (n = 67) both-column fractures. The extra-articular comminution zones are usually distributed between the posterior iliac fragment and anterior column fragment. High-variety type both-column fractures are usually combined with high and sharp posterior wall fragments, whereas low-variety type both-column fractures are usually accompanied by low and flat posterior wall fragments. The comminution zones in the acetabulum are mostly concentrated in the anterior and inferior parts of the acetabulum. The innominate bone is divided into 3 major parts in the both-column fracture, and the fracture center is located at the proximal of the acetabular dome. The both-column fractures are divided into low-variety and high-variety patterns. The location of the anterior column fracture determined the characteristics of the posterior wall fragment.

A 3D CT-based fracture map study of intra-articular distal radial fractures

Objective To map OTA/AO type B and type C distal radial fractures according to three-dimensional (3D) CT scan data, and to describe the morphological distribution of fracture lines. Methods A total of 468 cases of distal radius fractures admitted to the Affiliated Hospital of Chengdu University from January 2016 to March 2019 were analyzed and AO classification were performed. AO type B and type C fractures meet the inclusion criteria and then CT data were 3D reconstructed, and morphological description were performed on the fracture lines of each joint surface, including fracture shape angle, fracture area and fracture ratio. At the same time, the articular surface fracture model was superimposed on the standard model, then fracture line and fracture area distribution map were drawn to create the fracture map of intra-articular distal radial fractures. Result Intra-articular fractures of the distal radius were 209 cases, accounting for 44.7% (209/468) of the distal radius fractures, among which 67 cases of AO type B fracture. In type B fractures, average fracture height were 20.30±11.26 mm, average fracture width were 12.24±6.83 mm, average fracture area were 189.61±101.84 mm2, average angle were 57.23°±14.95°, and average area ratio of fracture (fracture zone area/joint surface area ratio) were 32.42%±10.24%. 142 cases were OA type C fracture, the average fracture height were 24.43±11.37 mm, average fracture width were 20.38±7.59 mm, average fracture area were 425.26±314.31 mm2, average angle were 51.26°±13.17°, and average area ratio of fracture were 73.81%±26.29%. According to fracture map formed by main fracture lines, five different fracture areas were identified: ① 63 cases in central area; ② 25 cases in Lister's nodule area; ③ 59 cases in scaphoid area; ④ 36 cases in lumbar fossa area; ⑤ 26 cases in lower iliac area. Main fracture lines were concentrated in the area on the dorsal side of the central area and the scaphoid area. The fracture lines of type B fracture mainly concentrated in scaphoid region, which accounted for 29.85% (20/67), and dorsal side and central area accounted for 26.87% (18/67). The fracture lines of type C fracture accounted for 27.46% (39/142) in scaphoid area and 31.69% (45/142) in central area. The fracture line of type C fracture increased in the lumbar fossa region (17.61%, 25/142) and the lower ulnar region (12.68%, 18/142) compared with type B fracture (28.69%). Compared with the type B fracture, the overall distribution of the fracture line of the type C fracture is more central. Conclusion The map of intra-articular fracture of distal radius was drawn and morphological distribution of fracture lines were quantified. Fracture-prone site and shape of fracture line were visually recognized. At the same time, description of articular surface fracture line and fracture area of type B and type C fractures of OA classification were improved, which may help with new classification and diagnosis. Key words: Radius fractures; Intra-articular fractures; Imaging, three-dimensional; Maps

Minimally invasive surgical treatment using 'iliac pillar' screw for isolated iliac wing fractures in geriatric patients: a new challenge.

There have been no prior case series of isolated iliac wing fracture (IIWF) due to low-energy trauma in geriatric patients in the literature. The aim of this study was to describe the characteristics of IIWF in geriatric patients, and to present a case series of IIWF in geriatric patients who underwent our minimally invasive screw fixation technique named 'iliac pillar screw fixation'. We retrospectively reviewed six geriatric patients over 65 years old who had isolated iliac wing fracture treated with minimally invasive screw fixation technique between January 2006 and April 2016. Six geriatric patients received iliac pillar screw fixation for acute IIWFs. The incidence of IIWFs was approximately 3.5% of geriatric patients with any pelvic bone fractures. The main fracture line exists in common; it extends from a point between the anterosuperior iliac spine and the anteroinferior iliac spine to a point located at the dorsal 1/3 of the iliac crest whether fracture was comminuted or not. Regarding the Koval walking ability, patients who underwent iliac pillar screw fixation technique tended to regain their pre-injury walking including one patient in a previously bedridden state. The visual analog scale score for pain at the last follow-up was quite satisfactory. Union was achieved in all patients at the last follow-up. Geriatric patients can have a form of IIWF caused by low-energy trauma that is a type of fragility fracture of the pelvis. Because subsequent deterioration of their walking status followed by a long period of non-weight bearing in geriatric patients could be as threatening as the fracture itself, the treatment paradigm for IIWF due to low-energy trauma in geriatric patients should differ from that due to high-energy trauma in most patients. In these types of fractures, minimally invasive surgical management that includes iliac pillar screw fixation can lead to good outcomes.

Proper Distal Placement of Tibial Nail Improves Rate of Malalignment for Distal Tibia Fractures

We hypothesize that the anatomic center of the distal tibia is just lateral and anterior to the center of the distal tibia articular surface in the coronal and sagittal planes, respectively, and that placement of the nail along this axis results in improved rates of malalignment when treating distal tibia fractures. Retrospective study. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. One Level I and one Level II trauma center. Two hundred three distal tibia fractures treated with intramedullary nailing (IMN) (primary cohort) whose main fracture line extended within 5 cm of the plafond to evaluate the rate of malalignment with distal nail placement. Additionally, we retrospectively reviewed a secondary cohort of 15 patients with proximal tibia fractures treated with intramedullary nailing for evaluation of passive anatomic distal nail position. Primary malalignment ≤5 degrees on the anteroposterior (AP), mortise, and lateral planes were evaluated in distal tibia fractures on perioperative radiographs. Primary Cohort: 85 patients met inclusion criteria for evaluation in the coronal plane. Overall malalignment in the coronal plane was 17.6%. There was a 2.9% (1/34) fracture malalignment rate when the nail was placed lateral to the center of the joint versus 27.5% (14/51) when placed medial to the center of the joint, with all occurring in valgus. This achieved statistical significance (P = 0.04). Correlation was highest when measuring the trajectory on mortise view using the talus as reference point. When evaluating the sagittal plane, there were 64 patients that met inclusion criteria with a 48% malalignment rate. Malalignment was greatest when the nail was placed in the anterior quadrant 100% (4/4), versus 50% (22/44) in the anterior middle, and 31.3% (5/16) in the posterior middle quadrant. This achieved statistical significance (P = 0.05). No nails were placed in the most posterior quadrant. Secondary Cohort: 15 patients met inclusion criteria for distal nail placement. The position of the nail in the coronal plane was measured on both the anteroposterior and mortise ankle radiographs using both the plafond and talus as a reference, whereas sagittal nail placement was measured on the lateral ankle radiographs. In the coronal plane, the mean passive distal position of the nail when referenced from the lateral cortex was 45.2% of the tibia plafond and 45.5% the width of the talus, or just lateral to the center of each. In the sagittal plane, passive nail placement was 40% the sagittal width of the joint measured from the anterior cortex, or just anterior to the center of the joint. This is the first patient series that defines optimal tibial nail placement in the treatment of distal tibia fractures. Distal placement of the nail just lateral to the center of the talus and plafond, or along mechanical axis of the tibia, results in significantly reduced rates of malalignment on the coronal plane when compared to nail placement medial to the center of the talus or plafond. Fluoroscopic judgment of distal nail trajectory was improved on the mortise view using the talus as a reference when compared to using the anteroposterior view. On the sagittal plane, anatomic passive nail placement is just anterior to the center of the plafond. However, nonanatomic nail placement just posterior to the center of the plafond had a lower incidence of malalignment compared with nails placed anterior to the center of the plafond. Further study of appropriate nail positioning on the sagittal plane is needed.

High-energy pilon fractures management: State of the art.

High-energy pilon fractures are challenging injuries. Multiple options are described for the definitive surgical management of these fractures, but there is no level I evidence for optimal management. The current management and recommendations for treatment will be reviewed in this article.Anatomical reduction of the fracture, restoration of joint congruence and reconstruction of the posterior column with a correct limb axis minimising the soft-tissue insult are the key points to a good outcome when treating pilon fractures.Even when these goals are achieved, there is no guarantee that results will be acceptable in the mid-term due to the frequent progression to post-traumatic arthritis.In high-energy fractures with soft-tissue compromise, a staged treatment is generally accepted as the best way to take care of these devastating fractures and is considered a local ‘damage control’ strategy.The axial cuts from the CT scan images are essential in order to define the location of the main fracture line, the fracture pattern (sagittal or coronal) and the number of fragments. All of this information is crucial for pre-operative planning, incision placement and articular surface reduction.No single method of fixation is ideal for all pilon fractures, or suitable for all patients. Definitive decision making is mostly dependent on the fracture pattern, condition of the soft-tissues, the patient’s profile and surgical expertise.Cite this article: Tomás-Hernández J. High-energy pilon fractures management: state of the art. EFORT Open Rev 2016;1:354-361. DOI: 10.1302/2058-5241.1.000016.

The morphological features of different Schatzker types of tibial plateau fractures: a three-dimensional computed tomography study.

BackgroundTibial plateau fractures are of great challenge to treat with open reduction and internal fixation, because fractures vary from simple to complex, with little or extensive articular involvement. Hence, recognition and comprehension of the fracture features will help orthopedic surgeons understand the injury mechanism better and manage these fractures by planning optimal surgical procedures. This study aimed to evaluate the morphological characteristics of tibial plateau fractures based on the Schatzker classification.MethodsA total of 186 patients with 188 tibial plateau fractures from 2010 to 2014 in our hospital were reviewed using a computed tomography scan and three-dimensional (3D) reconstruction. The main fracture line angles (FLA) of Schatzker types I, II, and IV were measured. For each fracture, depression depth was measured, and the depression zone was also located. Depression zones were overlapped to obtain a frequency diagram.ResultsSchatzker type I and II fractures had three subtypes: single anterolateral fracture, single posterolateral fracture, and complex fracture (the anterolateral and posterolateral parts). Schatzker type IV fractures were also divided into three subtypes: single posteromedial fracture, single anteromedial fracture, and the whole medial fracture. For various Schatzker types and subtypes of fracture, fracture depression clustered and occurred at different locations of the tibial plateau. A significant difference was observed in the depression depth among the different Schatzker types (P < 0.01, Kruskal-Wallis test), especially between Schatzker type III and other types (Nemenyi test). There was no difference in the depression depth among the subtypes of Schatzker type II, whereas the difference was significant between the two subtypes of Schatzker type IV.ConclusionsSchatzker type I, II, and IV fractures could be divided into three corresponding subtypes by FLA. Various Schatzker types of fractures differed in location and depth of depression. A proper operative approach should be made based on the morphological characteristics of individual types of tibial plateau fractures.

Chapitre 2. L'amélioration technique de l'être humain : introduction aux différents courants du débat

The main objective of this article is to suggest a panel of the different positions active in the human enhancement's debate, to analyze their arguments and to point out the dividing zones. The transhumanist movement is therefore presented in order to highlight the principal thematic of its philosophy, its means of action and the plurality of its subgroups. The purpose is to reassess its complexity in an introductory manner far from the usual, excessive simplifications. In a second time, the "bioconservative" movement is also examined in its foundations to emphasize the norms and principles that are undoubtedly shared by the opponents to the human being's modification. Then, the thinkers of the "liberal ethics" are exemplified as a more moderate alternative, although not flawless. Generally open-minded towards the application of enhancement technologies, they protect as an ultimate guardian, the harm principle, as well as the absolute respect of individual freedom. Once the protagonists are introduced, the true meaning of these positions is replaced in the context of the three main fracture lines: the human nature, the normality criterion and the equality principle. A complex debate indeed that we could summarize by a simple question: what will human do about the human in the 21st century?

Morphometric indices as indicators of tectonic, fluvial and karst processes in calcareous drainage basins, South Menorca Island, Spain

AbstractThis study proposes using morphometric indices to discriminate the processes that shape calcareous drainage basins. To illustrate this, a DEM of the southern part of Menorca Island (Migjorn) was created and basin slope, drainage density, hypsometric curve and integral, and the area occupied by open and closed dolines were extracted from it. These indices show an important dependence on tectonics, which govern the morphology of these drainage basins and encourage the predominance of karst and/or fluvial processes in the different sectors. The morphometric indices are clearly influenced by the geological Migjorn structure, a carbonate Upper Miocene reef platform gently folded as an asymmetrical anticline. The hypsometric integral and curve discriminate the influence of tectonics and structure whilst the drainage density and the proportion of open dolines are associated with basins with more pronounced fluvial processes. A cluster analysis based on these indices discriminated three sectors where different forms and processes are found. In the western and eastern sectors, rounded basins without major fractures predominate. The basins slope at less than 5°, and karst processes outweigh fluvial processes. The central sector, however, has steeper slopes, a clearly defined drainage system, and a predominance of fluvial over karst processes. Greater uplift in this sector has facilitated the formation of elongated basins that follow the main fracture lines. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Radial carpal bone fractures in 15 dogs.

Between 1977 and 1992, 15 adult dogs were presented to the Universities of Bristol, Glasgow, Liverpool and London with fractures of the radial carpal bone which had occurred without a known episode of violent trauma. Eleven of the dogs were boxers and the other breeds affected were a Pharaoh hound, rottweiler, springer spaniel and a greyhound. The condition was bilateral in three cases. Eleven dogs were treated surgically by cast immobilisation (four cases), fragment removal (one case), lag screw fixation (three cases), pan-carpal arthrodesis (one case) and lag screw reduction followed by pan-carpal arthrodesis (two cases). The remaining four dogs were treated conservatively with rest and tactical use of non-steroidal anti-inflammatory drugs. Follow-up periods ranged from two months to 11 years. Varying degrees of lameness, which tended to be exacerbated by exercise, persisted in all cases. The radial carpal bone appears to have at least three separate centres of ossification which eventually fuse; their planes of fusion correspond approximately to the two main fracture lines. These areas of fusion could be weak points within the radial carpal bone.

Study on the microstructures of skull fracture

The authors observed the edges of skull fractures under the scanning electron microscope. Many microfractures can be found along the main fracture lines. The width of the microfractures varies from 5 to 100 μm. They may be located either in the external compact bone or between the outer compact bone and diplöe, or in the diplöe. Those within the diplöe form transverse, longitudinal or spiral fractures of bony trabeculae. Collagenous fibre bunches in the bony matrix may be divided or broken and the different layers of collagenous fibre may be separated. The blood vessels inside the skull may be crosscut or longitudinally torn by the fracture lines. Sometimes the torn blood vessels may be drawn out of the Haversian canals. In antemortem fractures, the fibrin networks and red blood cells can be easily found in the depths of those cracks. The possible mechanism of formation of the microfractures and the possibility of differentiation between ante- and post-mortem fractures are discussed.

Advantages in the diagnosis and classification of intra-articular fractures of the calcaneus using computed tomography

The superiority of CT over conventional radiography in demonstrating intra-articular fractures of the os calcis was demonstrated in 34 patients. The advantages consist in being able to demonstrate the joint without superposition and the exact demonstration of the position, size, shape and number of fragments. Shortening or widening of the os calcis can be easily recognized, as well as fractures of the medial or lateral cortex. At the same time it is possible to evaluate soft tissues, particularly the peroneal ligament. The conventional classification of calcaneal fractures has been newly evaluated in the light of the ability to recognize involvement of the joint and the course of the main fracture lines.