Assessing the knot in a noose position by thyrohyoid and cervical spine fracture patterns in suicidal hangings using machine learning algorithms: A new insight into old dilemmas

Hanging is one of the most common suicide methods worldwide. Neck injuries that occur upon such neck compression - fractures of the thyrohyoid complex and cervical spine, occupy forensic pathologists for a long time. However, research failed to identify particular patterns of these injuries corresponding to the force distribution a ligature applies to the neck: the issue of reconstructing the knot in a noose position persists. So far, machine learning (ML) models were not utilized to classify knot positions and reconstruct this event. We conducted a single-institutional, retrospective study on 1235 autopsy cases of suicidal hanging, developed several ML models, and assessed their classification performance in a stepwise manner to discriminate between: 1. typical ('posterior) and atypical ('anterior' and 'lateral') hangings, 2. anterior and lateral hangings, and 3. left and right lateral hangings. The variable coding was based on the presence/absence of fractures of greater hyoid bone horns (GHH), superior thyroid cartilage horns (STH), and cervical spine. Subject age was considered. The models' parameters were optimized by the Genetic Algorithm. The accuracy of ML models in the first step was very modest (c. 60%) but increased subsequently: Multilayer Perceptron - Artificial Neural Network and k-Nearest Neighbors performed excellently discriminating between left and right lateral hangings (accuracy 91.8% and 90.6%, respectively). The latter is of great importance for clarifying probable hanging fracture biomechanics. Alongside the conventional inferential statistical analysis we performed, our results further indicate the association of the knot position with ipsilateral GHH and contralateral STH fractures in lateral hangings. Moreover, odds for unilateral GHH fracture, simultaneous GHH and STH fractures, and cervical spine fracture were significantly higher in atypical ('anterior' and 'lateral') hangings, compared to typical ('posterior') hangings.

Systematic review of laryngohyoid fractures in fatal falls: A potential mimicker of strangulation

Fractures of the laryngohyoid complex are classically associated with deaths due to strangulation. Recent studies, however, indicate the possible presence of such fractures in fatal falls. The primary focus of this systematic review is to analyze the characteristics of laryngohyoid fractures in the context of falls to aid in a more accurate interpretation of autopsy findings. Search for relevant literature occurred on PubMed on the 26th of October 2022, and Embase and Web of Science on the 5th of November 2022. Inclusion criteria included being a primary study, published in English, involving fatal falls and injuries to the laryngohyoid complex, and presenting sufficient details about the relevant cases. Four case reports and six descriptive retrospective studies were included in the final analysis yielding a sum of 38 cases. The risk of bias was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools. Potential limitations of this study include the inclusion of case reports and studies published in English only. The cumulative male-to-female ratio was 23:15 with a mean age of 48 years old. The fall height ranged from standing height to 60 m. Forty-three fractures to the laryngohyoid complex were identified with the thyroid cartilage most commonly affected, followed by fracture of the hyoid bone, and finally the cricoid cartilage. While cases of falls did indeed display hallmark laryngohyoid findings classically displayed in strangulation, they also featured unique presentations such as fractures of the clavicle and a reduced prevalence of conjunctival petechiae.

Costal cartilage fractures in blunt polytrauma patients - a prospective clinical and radiological follow-up study

Purpose

To assess the healing of costal cartilage fractures (CCFX) in patients with blunt polytrauma with follow-up imaging and clinical examination. Effect on physical performance and quality of life (QoL) was also evaluated.

Methods

The study group comprised twenty-one patients with diagnosed CCFX in trauma CT. All the patients underwent MRI, ultrasound, ultra-low-dose CT examinations, and clinical status control. The patients completed QoL questionnaires. Two radiologists evaluated the images regarding fracture union, dislocation, calcifications, and persistent edema at fracture site. An attending trauma surgeon clinically examined the patients, with emphasis on focal tenderness and ribcage mobility. Trauma registry data were accessed to evaluate injury severity and outcome.

Results

The patients were imaged at an average of 34.1 months (median 36, range 15.8–57.7) after the initial trauma. In 15 patients (71.4%), CCFX were considered stable on imaging. Cartilage calcifications were seen on healed fracture sites in all the patients. The fracture dislocation had increased in 5 patients (23.8%), and 1 patient (4.8%) showed signs of a non-stable union. Four patients (19.0%) reported persistent symptoms from CCFX.

Conclusion

Non-union in CCFX is uncommon but may lead to decreased stability and discomfort. Both clinical and radiological examinations play an important part in the post-traumatic evaluation of CCFX. CT and MRI visualize the healing process, while dynamic ultrasound may reveal instability. No significant difference in QoL was detected between patients with radiologically healed and non-healed CCFX. Post-traumatic disability was mostly due to other non-thoracic injuries.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10140-022-02066-w.

The Effect of Intraarticular Insulin on Chondral Defect Repair

OBJECTIVE

The aim of this study is to evaluate the effects of intraarticular insulin on the treatment of chondral defects.

DESIGN

Twenty-four mature New Zealand rabbits were randomly divided into 3 groups as control (Group 1), microfracture (Group 2), and microfracture and insulin (Group 3). Four-millimeter full-thickness cartilage defects were created to the weight-bearing surface on the medial femoral condyles of each rabbit. In the first group, any additional interventions were not performed. Microfracture was performed on defects in groups 2 and 3. Additionally, 10 IU of insulin glargine was administrated into the knee joints of the third group. Three months after surgery, the knee joints were harvested and cartilage quality was assessed according to Wakitani and ICRS (International Cartilage Repair Society) scores histopathologically. Insulin injections were performed into the knees of 2 additional rabbits without creating a cartilage defect to evaluate the potential adverse effects of insulin on healthy cartilage (Group 4).

RESULTS

The total ICRS and Wakitani scores of the insulin group were found to be significantly lower than the microfracture group but similar to the control group. No negative effects of insulin on healthy cartilage were detected. Intraarticular insulin after surgery has led to a statistically significant decrease in systemic blood sugar levels whereas the decrease observed after administration to intact tissues was not statistically significant.

CONCLUSIONS

Insulin had a negative influence on the quality of cartilage regeneration and had no effect on healthy cartilage. Intraarticular insulin administration does not cause significant systemic effects in intact tissue.

Osteochondral lesions of the talus

Osteochondral lesions of the talus occur infrequently and usually represent late sequelae of ankle trauma. Because of the functional significance of the talus and its limited capacity for repair, correct early diagnosis is important. Osteochondral fractures should be suspected in patients with chronic ankle pain, especially those with a prior ankle injury. Historically, plain radiographs have been used to stage lesions; more recently, magnetic resonance imaging and arthroscopy have been used. Non-surgical management remains the mainstay of treatment of acute, nondisplaced osteochondral lesions. Surgical management is reserved for unstable fragments or failure of nonsurgical treatment. Recent advances in osteochondral grafting have allowed reconstruction of the talar dome, leading to more predictable relief of pain and improvement of function.

[External severe laryngeal trauma with multiple fractures and airway compromise]

External laryngeal traumas are rare but clinically can cause important life-threatening injuries. We report the case of a 33 yeras old male who suffered a severe traffic accident: TCE, facial trauma with multiple fractures and laryngeal trauma with fracture of the thyroid cartilage and the hyoid bone. Because an important edema in the airway, it was not possible an orotracheal intubation and he required urgent coniotomy with later reconstruction surgery and tracheostomy. Actually our patient has been decanulated and the fibroscopic image of the larynx and its functionality is correct.

Enhanced concentration of COMP (cartilage oligomeric matrix protein) in osteochondral fractures from racing Thoroughbreds

The aim of the present study was to correlate the levels of COMP and aggrecan as indicators of tissue damage, in synovial fluid (sf) from carpal joints of acutely lame racehorses, with macroscopical lesions of articular cartilage (OA), osteochondral fractures and ligament tears found at arthroscopy. Sixty-three lame horses [49 Standardbred trotters (STB) and 14 Thoroughbreds (TB)] in conventional training and racing that underwent arthroscopy of their middle carpal or radiocarpal joints were included in the study. Intact as well as fragmented COMP and aggrecan released into the synovial fluid were quantified by western blot analyses and ELISA. The expression of COMP in tissues was estimated by mRNA in situ hybridisation and protein immunolocalisation in cartilage and osteochondral fractures. The concentration of sf-COMP was higher in TB with an osteochondral fracture than in STB with osteochondral fractures and TB and STB with OA. The chondrocytes in middle and deep zones of the articular cartilage of the osteochondral fragments (from a TB) expressed COMP mRNA, in contrast to the cartilage on the opposite side of the fracture where no expression was detected. In the synovial fluid from a joint (TB) with osteochondral fractures only intact COMP was present, whereas, fragmented COMP was more prominent in synovial fluid from a joint with OA. The concentration of sf-aggrecan did not differ between the two breeds, or between different lesions. The increased concentration of sf-COMP in TB with osteochondral fractures, but not in synovial fluid from equine joints with OA, is a novel finding. The results from this study indicate that elevated sf-COMP concentration in the joints of Thoroughbreds may be a useful marker for carpal joint osteochondral fragments.

Sleeve fracture of the patella in a child

Sleeve fracture of the inferior pole of the patella is a rare and distinctive fracture in children with few published reports. These fractures are frequently misdiagnosed and neglected. We highlight a case of a neglected and misdiagnosed sleeve fracture of the patella in an eleven-year-old boy. This was initially diagnosed as an avulsion fracture of the tibial tubercle. A good outcome was achieved after open reduction and internal fixation.

MR imaging findings in ulnar-sided wrist impaction syndromes

Ulnar-sided wrist impaction syndromes are a common source of ulnar pain and limitation of motion. These conditions refer to a group of pathologic entities that result from repetitive or acute forced impaction between the distal ulna and ulnar carpus or distal radius and surrounding soft tissues. MR imaging allows earlier detection of the bone and soft-tissue lesions that are present in the different ulnar-sided wrist impaction syndromes and is helpful in formulating the extensive differential diagnosis in patients with ulnar wrist pain and limitation of motion.

Principles of septal correction

The operation of septoplasty is often given to junior surgeons to perform and dismissed as a simple procedure. This can lead to unsatisfactory results with unnecessary morbidity for the patient and disillusionment for the surgeon. Trainee surgeons feel that the operation of septoplasty is poorly taught. Some common problems encountered during septal surgery are described and a variety of surgical solutions are offered.

Effect of Specimen Thickness on Fracture Toughness of Bovine Patellar Cartilage

Fracture toughness and crack tip opening angle were measured for bovine patellar cartilage using modified single-edged notch specimens of two thicknesses. There was no difference in fracture toughness between thin (0.7 mm) versus relatively thick (2.7 mm) specimens, but the crack tip opening angle at initiation of crack propagation was larger for the thin specimens (106 deg) than for the thick specimens (70 deg). Fracture toughness of the bovine patellar cartilage 1.03kJ/m2 was not statistically different than that reported previously for canine patellar cartilage 1.07kJ/m2 employing the same methods. Large variation in measurements for both bovine and canine cartilage are in part attributable to variation between individual animals, and are consistent with variation in other mechanical property measurements for articular cartilage. The observed reduction in crack tip opening angle with increased specimen thickness is consistent with behavior of some engineering materials, and demonstrates that specimen thickness influences fracture behavior for bovine patellar cartilage.

[Osteochondral lesions of the talus in adolescents]

Osteochondral lesions of the talus range from those confined to the hyaline cartilage covering the articular surface to those involving the subchondral bone. The lesion may not be apparent on the surface of the cartilage or it may be confined to the subchondral bone without cartilage involvement. These complex presentations often necessitates the use of computed tomography and magnetic resonance imaging to delineate the exact nature of the lesions. It has been shown that the frequency of osteochondral lesions increase following repetitive ankle sprains. Although the etiology is not well understood, both traumatic and atraumatic causes are thought to be effective. Nevertheless, early diagnosis and treatment of these lesions have improved considerably thanks to the developments in imaging techniques. It seems that arthroscopic chondral reconstruction methods using autologous chondrocyte and osteochondral transplantations will gain much interest in the near future.

Scanning Electron Microscopic Examination of Third Metacarpal/Third Metatarsal Bone Failure Surfaces in Thoroughbred Racehorses with Condylar Fracture

OBJECTIVE

To examine the fracture failure surfaces from Thoroughbred horses that had sustained a catastrophic condylar fracture.

SAMPLE POPULATION

Bone specimens from the failure surface were obtained from 12 Thoroughbred racehorses with catastrophic injury and 2 non-racing horses with accidental long bone fracture.

METHODS

Bone specimens from the failure surface of each fracture were incubated with gold microspheres to label microcracks before examination at x50 to x60,000 using scanning electron microscopy. Microcracking at the failure surface was assessed using a visual analog scale.

RESULTS

Branching arrays or clusters of microcracks were seen over a range of magnifications in adapted subchondral bone in the distal end of the MC3/MT3 bone from racing Thoroughbreds with a catastrophic displaced condylar fracture. In the palmar/plantar region, microcracking was associated with the formation of an array of macroscopic cracks in the condylar groove. A different pattern of microcracking was seen in specimens of bone from distal metaphyseal and diaphyseal MC3/MT3 failure surfaces from Thoroughbred racehorses with catastrophic fracture and non-racing horses with an accidental diaphyseal long bone fracture. Few microcracks were seen and typically did not form branching arrays.

CONCLUSION

These data suggest that propagation of condylar fracture in Thoroughbred racehorses is initiated by the formation of nanoscale microcracks in adapted subchondral bone that form during exercise-induced bone adaptation.

CLINICAL RELEVANCE

Accumulation and coalescence of branching microcracks into arrays or clusters appears to eventually lead to the development of macroscopic subchondral cracks in the condylar groove and initiation of a condylar fracture.

Altered fracture repair in the absence of MMP9

The regeneration of adult skeletal tissues requires the timely recruitment of skeletal progenitor cells to an injury site, the differentiation of these cells into bone or cartilage, and the re-establishment of a vascular network to maintain cell viability. Disturbances in any of these cellular events can have a detrimental effect on the process of skeletal repair. Although fracture repair has been compared with fetal skeletal development, the extent to which the reparative process actually recapitulates the fetal program remains uncertain. Here, we provide the first genetic evidence that matrix metalloproteinase 9 (MMP9) regulates crucial events during adult fracture repair. We demonstrate that MMP9 mediates vascular invasion of the hypertrophic cartilage callus, and that Mmp9(-/-) mice have non-unions and delayed unions of their fractures caused by persistent cartilage at the injury site. This MMP9- dependent delay in skeletal healing is not due to a lack of vascular endothelial growth factor (VEGF) or VEGF receptor expression, but may instead be due to the lack of VEGF bioavailability in the mutant because recombinant VEGF can rescue Mmp9(-/-) non-unions. We also found that Mmp9(-/-) mice generate a large cartilage callus even when fractured bones are stabilized, which implicates MMP9 in the regulation of chondrogenic and osteogenic cell differentiation during early stages of repair. In conclusion, the resemblance between Mmp9(-/-) fetal skeletal defects and those that emerge during Mmp9(-/-) adult repair offer the strongest evidence to date that similar mechanisms are employed to achieve bone formation, regardless of age.

[An avulsion (sleeve) fracture of the proximal patella pole in a child. Diagnosis, treatment and results in a patient after a fall onto the knee]

We report a case of an avulsion fracture (sleeve fracture) of the proximal pole of the patella in an 8 year old boy who fell onto his left knee. After the fracture was diagnosed, the patient under went surgery on the day of the accident. The articular cartilage and the upper fragment were reconstituted and fixed with transosseous sutures. A cast immobilisation in extension was used for 6 weeks and the patient regained full active mobility of the left knee joint after cast removal. A radiograph showed that the fracture had completely united. Diagnosis, pathomechanism and treatment strategies are discussed with reference to this rare case, and the literature is reviewed.

Analysis of neck injuries in hanging

Retrospective study of suicidal hangings was made on 175 cases (133 male victims, 42 female victims) for a 5-year period. The mean age was 47.33 +/- 17.51 years. The sample was divided in 4 groups according to the position of the ligature knot (anterior, right, left, and posterior hanging). The authors analyzed all visible injuries of soft tissues and bones and cartilage of the neck, and in 150 cases (85.7%), we established that there was at least one injury of these structures (hematoma or fracture for example). The most frequent injury was to sternocleidomastoid muscles. Fracture of throat skeleton was detected in 119 cases (68%). The proportion of fractures increases with age of the deceased. There was no clear correlation between frequency of neck injuries and type of hanging.

Magnetic resonance imaging of pediatric musculoskeletal trauma

Musculoskeletal injury in children is common and can lead to lifelong disability. The unique ability of magnetic resonance imaging (MRI) to visualize the cartilaginous ends of growing bones, bone marrow, and supporting soft-tissue structures makes it ideally suited for evaluation of injury in these patients and the complicating growth disturbance. This article reviews the role of MRI in several common pediatric musculoskeletal injuries and their related growth disturbances. A review of normal musculoskeletal growth and enchondral ossification and the magnetic resonance signal characteristics of the growing skeleton is provided as necessary background. The discussion includes MRI features of physeal fractures and posttraumatic growth arrest, epiphyseal and osteochondral injuries, stress fractures, avulsion injuries, and musculoskeletal soft-tissue injuries.

[The surgical treatment of fractures of the base of the fifth metacarpal bone]

Fractures of the base of the fifth metacarpal bone are relatively uncommon injuries. In contrast to similar fractures of the first metacarpal bone, various methods of treatment have been advocated. Some believe that cast immobilization or immediate unrestricted motion is a reliable method, while others recommend surgery and pinning or plate fixation. Fractures of the base of the fifth metacarpal bone are inherently unstable and inadequate reduction may result in pain, functional disability and osteoarthritic changes. We retrospectively reviewed 14 cases with intra-articular or extra-articular fractures of the base of the fifth metacarpal bone between the years 1991-1998. Patient treatment included closed reduction and percutaneous pinning using an image intensifier. Open reduction with multiple Kirschner pinning was implied in comminuted fractures and in cases when closed restoration of the articular surface was unfeasible. On follow-up examinations, all patients had good functional outcomes with no arthritic changes. We recommend reduction, restoration of the articular surface and pinning as the method of choice in the treatment of these fractures.

High-resolution outpatient imaging of the wrist

The authors describe their experience with magnetic resonance imaging (MRI) in the evaluation of pathologic conditions of the wrist in an outpatient setting. In that setting, because time and quality are both important factors, they have concentrated on developing protocols that will allow effective, time-efficient, high-resolution MRI of the wrist. With these wrist imaging protocols, they have evaluated the majority of commonly encountered pathologic conditions of the wrist. They have found that high-resolution images, which can be acquired in a very timely fashion when fast spin echo sequences are used in imaging protocols, will demonstrate the most common pathologic conditions, including triangular fibrocartilage and ligament tears in the wrist. They present the practical issues of patient position and imaging sequences as well as the imaging findings in those pathologic conditions.

Osteochondral injuries

Osteochondral injuries are an important type of musculoskeletal trauma that can lead to disabling arthritis if not recognized and treated appropriately in the early stages. The anatomic configuration and biomechanical function of a joint are important for understanding its particular pattern of osteochondral injury and the resultant imaging appearance. The imaging of osteochondral fractures and osteochondrosis dissecans (OCD) is reviewed in this article, with particular attention to differentiating surgical and nonsurgical lesions on the basis of their appearance with advanced imaging modalities. Computed tomography (CT) and magnetic resonance imaging (MRI) have improved both the sensitivity and specificity for detection and characterization of osteochondral injuries. MRI is currently the modality of choice for the detection and staging of osteochondral injuries. It has the greatest sensitivity owing to its ability to depict marrow edema and directly assess the fracture clefts of stage 3 lesions, as well as the morphology of articular cartilage. Newer strategies for differentiating stable from unstable osteochondral fragments include MR arthrography and intravenous contrast-enhanced MRI.

[Os subfibulare in children secondary to an osteochondral fracture]

PURPOSE

The understanding of the os subfibulare in childhood.

MATERIAL AND METHODS

A retrospective study of radiographs following for indirect ankle injury in childhood over a period of two years.

RESULTS

The daily use of an oblique view during the exploration of ankle sprains in emergency has allowed us to image 12 small and linear chiplike fractures of the fibula by avulsion of the antero-medial part of the malleolar's tip where the talo-fibular collateral ligament is attached. Two children were reviewed one year after for a recurrent sprain: a larger and rounder fragment of bone has taken the place of the first piece of bone.

CONCLUSION

Symptomatic ossicles of the lateral malleolus in children is frequently if not always the consequence of an avulsion of the tip of the fibula. The outcome of these children may be a localised tenderness and recurrent episodes of sprains for minimal injury due to the weakness of the lateral ligament.

Subtle fatal manual neck compression

A critical analysis of the postmortem diagnostic criteria for asphyxia leads to a difficulty that has significant implications for the forensic pathologist. The difficulty is that there are no universally recognized pathognomic signs of asphyxia, but pathologists frequently make this diagnosis based on observations that individually have indeterminate significance but combined together, in the appropriate context, have diagnostic value. This leads to the question: if asphyxia has no recognizable signs at autopsy how are we able to diagnose this entity in the latter circumstances? This problem can be solved by defining the minimally adequate diagnostic criteria for compressive neck injury. These criteria are potentially well-defined but currently lacking, in part, due to incomplete morphological characterization of the injuries that frequently occur in strangulation. The problem is especially challenging because the signs of strangulation form a spectrum of degree from minimal to marked and there is no consensus as to the minimal number and nature of lesions that is required to make the diagnosis of strangulation. In the present review of lesions that are commonly encountered in strangulation, intracartilaginous laryngeal haemorrhages and laryngeal cartilage microfractures are considered to have unrecognized diagnostic value, and these lesions are described in detail. A triad of haemorrhages (subepithelial laryngeal haemorrhage, intralaryngeal muscular haemorrhage, and intracartilaginous laryngeal haemorrhage) is discussed in the context of developing a definition of strangulation based on morphological criteria in the absence of overt mechanical injuries to the neck. Although definitive criteria for cases with minimal findings are still lacking, several lesions have putative diagnostic value.

Imaging of osteochondral injuries

Acute injuries can produce fragments consisting of cartilage alone or cartilage and underlying bone. A purely cartilaginous fragment creates no direct radiographic abnormalities, whereas one containing calcified cartilage and bone appears as a radiodensity. The advent and refinement of MR imaging have led to the detection of occult injuries of subchondral bone and cartilage that can escape identification on routine radiographic analysis. The available data appear to indicate a substantial role for MR imaging in the analysis of lesion stability in cases of osteochondritis dissecans; however, further studies are required to determine its advantages over other methods, in particular, arthroscopy. Indirect evidence of cartilage abnormality on MR images relates to the identification of fluid at the interface between the fragment and the parent bone. The MR imaging technique influences dramatically whether such fluid is identified. MR arthrography employing the intra-articular injection of gadolinium compounds can be advantageous in the delineation of the chondral surface and in the detection of intraarticular bodies. Optimally, MR imaging would allow direct analysis of the cartilage surface, and specific imaging sequences that are most suited to this analysis are still evolving.

Chondral and osteochondral injuries. Diagnosis and management

Osteochondral lesions are relatively common and usually occur as a result of trauma. They often are unrecognized acutely and lead to osteochondral defects and eventually osteoarthritis. Detection of these lesions has been aided by bone scan, CT, and MR imaging. Acute osteochondral fragments can be replaced and internally fixed. Chronic osteochondral defects can be treated with several methods designed to stimulate healing by either fibrocartilage or healing by transplantation of bone and cartilage or cartilage alone. The goal of all treatment methods is to provide a stable, congruent joint surface, restore function, and prevent the evolution of osteoarthritis in the injured joint.

Microfracture techniques in the treatment of osteochondral injuries

Although many methods currently are available to treat articular cartilage lesions in the knee, microfracture has many inherent advantages. No other technique has been studied in the athletic population, and, in fact, most other procedures have been studied in the arthritic knee or in a mixed population of patients. Blevins et al have shown microfracture to be an effective tool in the treatment of chondral defects in both recreational and high-level athletes with mean follow-up of 3.7 years. Furthermore, microfracture is minimally invasive because it is arthroscopic through standard portals in most cases. The subchondral plate is preserved, unlike in other techniques, improving load-bearing characteristics following healing. No heat necrosis or polishing is introduced into the subchondral bone and marrow with microfracture. The depth of penetration and location of puncture is controlled readily with the various awl angles. Surgical equipment and supply costs are minimal, without the need for expensive cell cultures or nonstandard equipment. No harvest site morbidity is present, unlike osteochondral, perichondral, periosteal, or chondral autograft procedures. Microfracture is not overly demanding technically, but emphasis must be placed on meticulous handling of the subchondral plate and surrounding healthy cartilage and adequate débridement of unhealthy cartilage. Finally, a good surgical technique is only as good as its rehabilitation. Strictly emphasizing the need for compliance with weightbearing restrictions and the use of CPM is essential to successful patient rehabilitation.

Rupture of the quadriceps tendon after arthroscopic lateral meniscectomy: A postoperative complication?

We report a case of complete quadriceps tendon rupture that occurred a few days after arthroscopic lateral meniscectomy. Complications following arthroscopy are rare; there have been many reports of quadriceps tendon rupture in the literature, but none by this kind of mechanism.

[Diagnostic imaging of acute and chronic osteochondral lesions of the talus]

Acute fractures involving the articular surface of the talus run parallel to the surface and are confined to the cartilage and/or the immediate subchondral cancellous bone. Subchondral microfractures ("bone bruises"), osteochondral fractures and solely chondral fractures are different manifestations of impaction injuries that affect the articular surface. This article reviews the radiologic appearance of acute osteochondral lesions of the talus and comments on the role of the noninvasive imaging modalities. Conventional radiography and MRI provide the most relevant information and are widely discussed. A MRI classification is presented emphasizing the distinction between lesions with intact and disrupted cartilage. Osteochondrosis dissecans (OCD) is a chronic osteochondral lesion. It is diagnosed in most cases by conventional radiography. MRI has become a decisive tool in staging the lesions. Intact cartilage and contrast enhancement of the lesions are findings of MRI stage I. Cartilage defects with or without incomplete separation of the fragment, fluid around an undetached fragment, cysts larger than 5 mm in diameter and a dislodged fragment are MRI findings observed in stage II and operative treatment has to be considered.

Why is the adolescent joint particularly susceptible to osteochondral shear fracture?

A biomechanical investigation of the dynamic shear failure of the osteochondral region of immature, adolescent, and mature bovine cartilage bone laminates was performed. The osteochondral junction was loaded in pure shear under impact conditions through the cartilage layer only. The results indicate the adolescent tissue fails at a nominal shear stress of 2.0 MPa, whereas the immature and the mature tissues fail at 3.8 MPa and 2.6 MPa, respectively. The adolescent tissue had a significant reduction in the fracture toughness of its osteochondral junction compared with that of the immature or mature tissues. The fracture toughness, describing the energy required to initiate and propagate a crack to failure, was 3.6 kN/m, 2.3 kN/m, and 10.2 kN/m for the immature, adolescent, and mature bovine tissues, respectively. This significant reduction associated with the adolescent osteochondral junction is explained in terms of the structural changes occurring within this important anchoring region during maturation. These findings question the wisdom of subjecting the adolescent joint to high levels and rates of loading.

Incidence of lateral talar dome lesions in SER IV ankle fractures

Osteochondral lesions of the talar dome are commonly the result of ankle trauma. While the technique of surgical repair of ankle fractures has been well reported, there are no studies that correlate the presence or absence of talar dome lesions. A possible explanation for this may be lack of intraoperative inspection of the talar articular surface. This retrospective study evaluates the incidence of lateral talar dome lesions in 50 supination-external rotation stage IV ankle fractures. Specifically, operative reports were reviewed for the presence of lateral talar dome lesions documented through intraoperative inspection. Overall, 19 of 50 fractures, or 38%, were found to have a lateral talar dome lesion. While the bimalleolar and deltoid ligament tear type fractures exhibited more talar dome lesions, there was no significant difference between these two fracture types (p = .1111). There was no statistically significant difference among the three types (unimalleolar, bimalleolar, and trimalleolar) of supination-external rotation ankle fractures (p = .0804). The authors conclude that intraoperative inspection of the lateral talar dome should be a routine part of ankle fracture repair.

Biomechanics of nasal septal trauma

Fractures of the nasal complex are the most common facial fracture. This is due to the fact that the nose is the most anteriorly projecting facial structure and is a composite structure of bone, cartilage, and soft tissue. Furthermore, the forces required to cause significant injury are less than that causing other facial fractures. Because of the wide range of activities and mishaps that cause nasal trauma, the instruments of injury range from bicycle handles to elbows. The causes, clinical anatomy, and future considerations regarding nasal septal trauma are discussed in this article.

[Healed fractures of the larynx and lingual bone in forensic autopsy]

Laryngohyoid fractures are a frequently investigated matter, especially in the forensic literature. On the other hand, there are only very few (old) forensic reports of such fractures in survived cases. However, healed fractures are not seldom found in forensic autopsies: In a personal series of 1160 forensic autopsies (adult persons) a careful dissection of the laryngohyoid complex was done by 1 investigator. Only a macroscopic examination of the cartilages was carried out; radiographs and histological slices were not regularly made. Therefore only a part of existing old fractures is detectable; for example, healed fissures are not visible with this simple method. Furthermore, asymmetries of the thyroid laminae cannot be declared as posttraumatic without additional examination, because this condition is described as possible anatomic anomaly. From that, the injury frequencies presented here only mark the lower threshold of the existence of such findings. Healed fractures of the upper thyroid horns and the major hyoid horns can be easily detected even in a routine examination, if healing resulted in a fixed dislocation or apposition of bone surrounding the former fracture site. In the present series, this was the predominant localization of old fractures: the upper thyroid horns (43 cases), followed by the hyoid cornua (12 cases), a combination of both sites (5) and cricoid fractures (5). Of the total 65 healed fractures (5.6%), 35 were found in the group of 290 chronic alcoholics (12.1%) and only 3.4% in non-alcoholics. In the subgroup of middle-aged alcoholics, the fracture rate increased up to 19%. However, this group did not present a higher rate of fresh laryngohyoid injuries (not related to strangulation) than the other cases. The old fractures probably resulted from minor "daily" injuries (like falls), which are common, especially in chronic alcoholics. The frequency of such findings should be in mind if an apparently fresh fracture, found in an actual autopsy, should be related to the cause of death: there is a real chance, that this fracture occurred prior, and without causal connection to the factors resulting in death. Therefore a histological examination of the age of this finding is necessary. Cricoid fractures are quite uncommon, except in serious external neck trauma. In 1 of our 5 cases, this fracture was caused by repeated cruelty, finally resulting in death.

[30 years experience in articular fractures of the calcaneus bone]

Results of 150 (123 in males, 27 in females) articular fractures of the calcaneus treated by various methods over period of 30 years have been evaluated. Mean age of the patients was 43 years. Minimum follow-up was 18 months. An analysis of the material indicates the need for reduction in every case. Westhues method is suitable for tongue type fracture, joint depression type should be managed by Palmer's method. Best results have been achieved after K-wire fixation of the reduced fracture and early mobilization. In fractures with no displacement or with a minor one functional treatment led to good results also. Unreduced fractures gave poor results; pain below lateral ankle was produced by compression of peroneal tendons with deformed calcaneus. Seventy per cent of the results were rated good, 15% fair and 15% poor.

Arthroscopic treatment of osteochondral lesions of the talar dome: a retrospective study of 48 cases

We treated 48 symptomatic osteochondral lesions of the talar dome arthroscopically. Of these, 18 patients had an osteochondral fracture with a loose fragment located in every case on the anteriolateral side of the talus. Treatment consisted of removal (16 cases) or fixation (2 cases) of the bone fragment. Thirty patients had chronic lesions (27 subchondral necrosis with a sequestrum and 3 extensive cysts). The lesion was posteromedial in 27 cases and the treatment consisted of removal of the sequestrum with curettage of the subchondral bone necrosis (27 cases) or transchondral drilling if the cartilage surface was intact (3 cases). All the patients were clinically and radiogically reviewed with a mean follow-up of 5 years (7 months to 11 years). Patients treated for an osteochondral fracture obtained significant better results (16 excellent or good results out of 18 cases) than those treated for chronic lesions (20 excellent or good results out of 30 cases). On radiographic examination, we noticed that, even at the longest follow-up, the bone healing was usually incomplete and the bone defect persisted indefinitely in case of extensive subchondral bone necrosis. The articular surface could be seen in 11 cases (8 computed arthrotomographies, 1 magnetic resonance imaging, and 2 second-look arthroscopies). The fibrous cartilaginous surface was apparently regular in 6 cases without any clear correlation with our clinical results. This study suggests that we must make a distinction between osteochondral fractures (recent or not healed) located in the anterolateral part of the talar dome, which carry a good prognosis, and necrotic lesions located medially, which are less likely to have a favorable outcome.

[Knee injury in children]

The diagnosis approach after knee injury in children must be carefully taken care of the growth plates but it is necessary to emphasize the frequency of the ligament and intra-articular lesions, and on the other hand to consider their benign reputation. Clinical and conventional radiologic examination give in most of the cases the correct diagnosis. For the others an examination under general anesthesia ++ is necessary to distinguish the ligament and the growth plate lesions. MRI must not replace the arthroscopy which is necessary for an haemarthrosis with a stable knee or a little isolated anterior instability. The non-surgical treatment is indicated for benign sprain and non-displaced or mid-displaced fractures if the reduction is perfect and stable. All the other lesions need a surgical treatment which must be the most conservative as possible, especially for the meniscus, because their integrity is a guarantee for the quality of the long term result.

Musculoskeletal trauma in children

MR imaging has facilitated the study of pediatric injuries by demonstrating the extraosseous and cartilaginous component of these lesions. In injuries to the epiphysis and physis, osteochondral injuries and avulsion injuries, the cartilaginous component is usually the most important part of the lesion. Stress fractures and other injuries to the marrow also can be demonstrated with MR imaging. In the context of musculoskeletal injuries in children, MR imaging is most valuable in demonstrating the extent of injuries to radiographically occult areas.

Expression of human bone morphogenic protein 7 in primary rabbit periosteal cells: potential utility in gene therapy for osteochondral repair

A commonly encountered problem in orthopedics is bone and cartilage tissue injury which heals incompletely or without full structural integrity. This necessitates development of improved methods for treatment of injuries which are not amenable to treatment using current therapies. An already large and growing number of growth factors which play significant roles in bone remodeling and repair have been identified in the past few years. It is well established that bone morphogenic proteins induce the production of new bone and cartilage. An efficient method of delivery of these growth factors by conventional pharmacological means has yet to be elucidated. We wished to evaluate the use of retroviral vector-mediated gene transfer to deliver genes of therapeutic relevance for bone and cartilage repair. To determine the feasibility of using amphotropically packaged retroviral vectors to transduce primary rabbit mesenchymal stem cells of periosteal origin, primary periosteal cells were isolated from New Zealand white rabbits, transduced in vitro with a retroviral vector bearing both the nuclear localized lacZ marker gene and the neo(r) gene, and selected in G418. We used a convenient model for analysis of in vivo stability of these cells which were seeded on to polymer scaffold grafts and implanted into rabbit femoral osteochondral defects. The nuclear localized beta-galactosidase protein was expressed in essentially 100% of selected cells in vitro and was observed in the experimental explants from animals after both 4 and 8 weeks in vivo, while cells transduced with a retroviral vector bearing only the neo(r) gene in negative control explants showed no blue staining. We extended our study by delivering a gene of therapeutic relevance, human bone morphogenic protein 7 (hBMP-7), to primary periosteal cells via retroviral vector. The hBMP-7 gene was cloned from human kidney 293 cell total RNA by RT-PCR into a retroviral vector under control of the CMV enhancer/promoter. Hydroxyapatite secretion, presumably caused by overexpression of hBMP-7, was observed on the surface of the transduced and selected periosteal cells, however, this level of expression was toxic to both PA317 producer and primary periosteal cells. Subsequently, the strong CMV enhancer/promoter driving the hBMP-7 gene was replaced in the retroviral vector by a weaker enhancer/promoter from the rat beta-actin gene. Nontoxic levels of expression of hBMP-7 were confirmed at both the RNA and protein levels in PA317 producer and primary periosteal cell lines and cell supernatants. This work demonstrates the feasibility of using a gene therapy approach in attempts to promote bone and cartilage tissue repair using gene-modified periosteal cells on grafts.

"Hidden" laryngeal injuries in homicidal strangulation: how to detect and interpret these findings

These studies were designed to demonstrate that the usual method of laryngeal dissection carries a significant risk of overlooking important laryngeal injuries. Formalin-fixed hyoid-larynx complexes were prepared in a prospective forensic study involving 191 cases of homicidal strangulation, 1984 to 1997. The basic steps of the applied method included: complete resection of the thyroid cartilage, a horizontal incision through the cricoid cartilage before opening the larynx dorsally, inspection of the laryngeal joints, and incisions of the laryngeal muscles. Using this procedure allowed us to detect the following injuries, which otherwise would have been destroyed or overlooked: (a) 17 incomplete fractures restricted to the dorsal surfaces of the thyroid laminae and 10 incomplete or non-dislocated fractures of the cricoid cartilage. In 7 cases, such a "hidden" fracture was the only laryngeal injury resulting from neck compression. (b) Extensive laryngeal muscle hemorrhages, especially of the vocal folds, were found in almost half of all cases, more rarely in strangulation by ligature and more frequently in manual strangulation. Gross hemorrhages were the decisive local laryngeal finding in 19 cases. (c) Laryngeal joint injuries (bleedings) were found in 18% to 52% of the different strangulation types. (d) Hemorrhages of the laryngeal mucosa were common findings that occur in about 60% of all cases; only in rare cases do such bleedings have a special diagnostic value. The quantity and significance of findings obtainable from complete preparation clearly document Camps's demand made in 1976 to dispense with the usual laryngeal dissection technique (dorsal scissor incision through the cricoid cartilage), at least in (questionable) strangulation cases.

Fracture of the anterior superior process of the calcaneus: an often misdiagnosed fracture

Fracture of the anterior superior process of the calcaneus has been considered an unusual injury. Following a sudden twist there is immediate pain on the outer aspect of the mid-portion of the foot and discomfort on weight-bearing. Three mechanisms of injury have been reported to cause the fracture. The diagnosis is often missed, and prolonged disability and local pain at the calcaneocuboid joint deserve further consideration. Oblique X-rays of the foot are helpful to visualize the fracture. Type III fractures may cause cartilage lesions and arthrosis; therefore, one should not wait long before excision or refixation of the fragment.

MRI of fractures of the distal radius: comparison with conventional radiographs

OBJECTIVE

To compare the evaluation of fractures of the distal radius with MRI and conventional radiographs. To demonstrate the ability of MRI to detect unsuspected soft tissue derangement accompanying this common injury.

DESIGN AND PATIENTS

Twenty-one consecutive inpatients admitted following fracture of the distal radius underwent preoperative evaluation with both conventional radiographs and MRI. In each case, analysis was made of both the osseous and soft tissue injury. MRI findings were compared with those identified on conventional radiographs and at subsequent surgical fixation.

RESULTS

Of 21 patients with fractures of the distal radius, 20 had extension to the radiocarpal articulation, 14 had distal radio-ulnar joint extension and 5 had avulsion of the ulnar styloid. Occult carpal bone fractures accompanying fracture of the distal radius were identified in two patients: one of the capitate and the other of the second metacarpal base. Ten patients (48%) had associated soft tissue injury: six patients had scapholunate ligament rupture, two patients had disruption of the triangular fibrocartilage, one patient had extensor carpi ulnaris tenosynovitis and one patient had a tear of a dorsal radiocarpal ligament. Of five patients with ulnar styloid avulsions, none had evidence of triangular fibrocartilage tears.

CONCLUSION

MRI affords better evaluation of osseous injury accompanying distal radial fractures than conventional radiographs. Intra-articular soft tissue injury accompanies distal radial fractures in almost 50% of cases. Scapholunate ligament disruption commonly accompanies intraarticular fracture through the lunate facet of the distal radius. Fracture of the ulnar styloid is infrequently associated with tear of the triangular fibrocartilage.

Effect of impact load on articular cartilage: development of an intra-articular fracture model

OBJECTIVES

To investigate the biological and mechanical effects of a single-impact load on articular cartilage.

DESIGN

An in vitro laboratory study was performed using mature bovine cartilage and bone, and isolated cartilage explants. Each specimen was impacted with a single load applied with a specially designed impactor and materials test machine. Chondrocyte metabolic activity and cartilage structural integrity was investigated using force displacement curves, radionuclide labeling, histology, and changes in water content.

SETTING

Laboratory for Soft Tissue Research, New York, New York, U.S.A.

SPECIMENS

Viable mature bovine cartilage and cartilage and bone explants.

MAIN OUTCOME MEASUREMENTS

Mechanical failure, proteoglycan synthesis, water content, histology, radiography, and scanning electron microscopy changes occurring during the twenty-four-hour period immediately following impact.

RESULTS

Force/displacement curves for the cartilage and bone explants demonstrated two failure-stress peaks, the first at fifty megapascals, representing cartilage failure, and a second peak at seventy-five megapascals, representing bone failure. Fine grain radiographs, histology, and scanning electron microscopy all confirmed the destruction of the cartilage in the area of direct impact (zone I) and subchondral bone failure and the detachment of the cartilage within the lesser impacted area (zone II). Proteoglycan synthesis was reduced significantly (p < 0.05) in the areas of direct impact (zone I) compared with areas with less or no impact (zones II and III, respectively). Significantly greater water content (p < 0.05) was found within the cartilage of zone I compared with zones II and III.

CONCLUSIONS

Significant and possibly irreversible articular cartilage damage occurs after a single high-energy impact load.

Lesions of the triangular fibrocartilage in fractures of the wrist

MRI conducted in 32 cases of distal fracture of the radius a mean of 93 days after trauma allowed for the identification of various lesions of the soft tissues among which those of the triangular fibrocartilaginous complex. These observations confirm the presence of lesions of the triangular fibrocartilaginous complex (TFC) among immediate complications of distal fractures of the radius and the diagnostic role of MRI in post-traumatic ulnar pain.

Subfracture insult to a knee joint causes alterations in the bone and in the functional stiffness of overlying cartilage

The current criteria used by the automotive industry for predicting joint injury are based on fracture of bone, but clinical studies suggest that chronic diseases such as osteoarthrosis can occur from a single blunt insult without bone fracture. In the current study, blunt insults were delivered to the patellofemoral joints of rabbits without producing bone fractures. Biomechanical and histological studies were performed on joint tissues at various times after insult. The functional integrity of the retropatellar cartilage on the lateral facet was measured with mechanical indentation experiments, and the thickness of the subchondral bone was measured from histological sections. Impacts produced surface lesions on the retropatellar cartilage. The thickness of the subchondral bone in representative animals tended to increase with time after insult, and the bone exhibited significant thickening at 12 months. The overlying cartilage showed signs of degeneration. However, the mechanical stiffness of the cartilage did not change until 12 months after the insult.

An unclassified fracture of the talus

The following is a case report detailing what appears to be a previously unreported and unclassified osteochondral fracture of the posterior talar facet. This case report will detail the diagnosis and treatment of the fracture, as well as provide a brief history of previously reported osteochondral lesions involving the talus. The authors suggest a new classification method for these types of fractures.

Imaging of skeletal and soft tissue injuries in and around the knee

This article addresses the place of MR imaging in the diagnosis of knee injuries. MR imaging of subtle fractures and bone contusions is described with emphasis placed on those types of fractures frequently associated with specific patterns of soft tissue injury. Soft tissue injuries are divided into ligamentous, meniscal, and muscular; each is discussed separately. The MR imaging appearance of these lesions is explained.

[Fractures of the wrist with cartilage rupture in young adults. Apropos of 18 cases]

Distal radius impaction fractures are not rare. They present a dual problem for the surgeon: the difficulty of establishing the exact pathological anatomy of the fracture, and of obtaining stable anatomic reduction. The authors report their experience of 18 distal radius impaction fractures in young patients after violent trauma (motor vehicle accident). We subdivided these fractures using Kapandji and Müller's classifications: 12 type 9 or C3, 4 type 5 or B1 and 2 type 4 or C1. The mean depth of impaction of the scaphoid fossa or lunate fossa ("die punch fracture"), or centrally was measured at 5 mm on preop X-rays or on CT scan. After radiographs of the wrist in traction under anaesthesia, open reduction was performed in 14 cases (78%). A volar approach with plate fixation was performed in 3 cases. A dorsal approach with internal fixation with k-wires and an external fixator was performed in the other 11 cases. A bone graft was necessary in 10 cases when the bone defect was significant. The four remaining patients were treated with percutaneous k-wires and external fixation. We reviewed these 18 patients after a mean follow-up of 27 months. The mean age at the time of the accident was 37 years. The results were graded on the Green and O'Brien scale. Results were excellent in 1 case, good in 11 cases, fair in 5 cases, and poor in 1 case. We believe that impaction fractures always require open reduction with or without the addition of bone graft depending on the degree of the impaction. This is because of the risk of arthritic degeneration with this kind of fracture, with articular incongruence (more than 2 mm), and with chondral injuries on the radial or the carpal aspect of the wrist joint. Also, when there is a distal radio-ulnar joint injury (D.R.U.J. dislocation or distal head ulna fracture), the joint must always be stabilized to avoid secondary displacement.