Radial Notch Research Articles

Osteoarthritis of Proximal Radioulnar Joint: Computed Tomography-Based Assessment and Associations with Clinical Findings.

Although many studies have focused on the degenerative changes of the ulnohumeral and radiohumeral joints in osteoarthritis (OA) of the elbow, the proximal radioulnar joint (PRUJ), which facilitates the pronation and supination motions of the forearm, has not been comprehensively evaluated. To assess the prevalence of PRUJ OA in patients diagnosed with OA of the elbow using computed tomography (CT) images and to establish an association between the CT findings and clinical manifestations. Cross-sectional study; Level of evidence, 3. Between 2010 and 2022, a total of 85 consecutive patients who were scheduled to undergo osteocapsular arthroplasty for OA of the elbow and had undergone preoperative CT imaging were included in the study. As a control group, 85 patients who underwent CT scans of the elbow for reasons other than OA of the elbow were selected and matched to patients in the OA group. CT findings of OA in the PRUJ, including osteophytes, joint space narrowing, subchondral cysts, and loose bodies, were evaluated. Inter- and intraobserver agreement analyses for CT findings were performed. The relationship between the CT findings of OA in the PRUJ and OA of the elbow classification systems (Broberg-Morrey, Hasting-Rettig, and Kwak) as well as clinical manifestations (range of motion [ROM], Mayo Elbow Performance Score, and visual analog scale for pain) were evaluated. Patients in the OA group showed osteophytes in the radial notch (81.2%), osteophytes in the radial head (45.9%), joint space narrowing (54.1%), loose bodies (25.9%), and subchondral cysts (23.5%) involving the PRUJ. Both the interobserver (κ = 0.866) and intraobserver agreements (κ = 0.933) for CT findings of PRUJ OA were almost perfect. The CT findings of PRUJ OA were associated with the severity of OA of the elbow in Cochran-Armitage Trend analysis (with Brogberg-Morray, r = -2.624, P = .011; with Hasting-Rettig, r = -3.421, P = .002; with Kwak, r = -2.266, P = .032). The presence of radial notch osteophytes restricted ROM in the flexion-extension arc and pronation-supination arc (P = .009 and P < .001, respectively). PRUJ OA could be identified using CT imaging and showed radial notch osteophytes, joint space narrowing, loose bodies within the joint space, and subchondral cysts. PRUJ OA was related to overall OA of the elbow and may contribute to reduced ROM in the elbow joint. Therefore, preoperative evaluation of PRUJ OA can aid in the surgical planning of osteocapsular arthroplasty for OA of the elbow.

Investigation of patch application failure behaviors according to fiber orientation difference at notched composite plates

In this study, the damage behaviors of different type notched composite plates bonded with external composite patches were investigated experimentally under static tensile test. Eight-layer woven glass fiber reinforced epoxy resin matrix composite plates and epoxy based adhesive were used as materials. Notch type, fiber orientation angle, double side repair and single side repair were used as parameter. Effects of fiber orientation angle was investigated for 0 ° , 15 ° , 30 ° and 45 ° . Radial notch in the center (Type I), semicircular notch on the plate edge (Type II), a circular hole in the plate center (Type III) and U notch at the edges (Type IV) have been examined for 4 different notch types. The outstanding feature of this study is that many parameters were compared for many samples under the same experimental conditions. The composite plates and patches were used from same materials. Reducing of the damage loads has been observed for all notch types depending upon the increasing of fiber orientation angle significantly. In addition, that patch application to different fiber orientation plates is quite effective on damage loads. The extension was changed depending on the notch geometry at unrepaired composite. The load increasing rate is between + % 24 and + % 189 for one-sided bonded repair; + % 60 and + % 349 for two-sided bonded repair compared to the unrepaired samples. The results of this work can serve as a guide for workers to improve repair quality and durability in an understandable way.

Morphometrics of the coronoid process and the radial notch of the ulna: implications for fracture assessment

PurposeA comprehensive analysis of the morphology of fractures of the coronoid process (CP) can aid diagnosis and guide treatment. The involvement of the radial notch of the ulna (RN)—e.g., in anterolateral facet fractures and transverse fractures of the CP—may influence the biomechanical conditions of the proximal radioulnar joint. However, the morphometric relation between the CP and the RN and the extent to what the proximal radioulnar joint can be affected in these types of fractures is unknown.MethodsA total of 113 embalmed, cadaveric ulnae were dissected. All soft tissue was removed. Strictly lateral, high-resolution photographs were taken and digitally analyzed. The height of the CP and its relation to the RN was measured. Sex differences and correlations between measured parameters were calculated.ResultsMean height of the CP was 16 mm (range: 12–23 mm; SD: 2). Mean height of the RN was 16 mm (11–25 mm; 2.2). The 50% mark of the CP corresponded to 18% (0–56%; 11.2) of the height of the RN. No significant differences were found between male and female specimens.ConclusionThe RN of the ulna extends only to a small part to the CP. Transverse or anterolateral fractures of less than 50% of the coronoid process may involve only a small portion of the proximal radioulnar joint.

Experimental study of the transport characteristics of fractional-order vortex beams in a turbulent atmosphere simulator

Fractional vortex beams have attracted increasing attention due to their complex yet intriguing physical properties, such as radial notch intensity distribution and higher degrees of modulation in orbital angular momentum. In this study, we experimentally investigated and compared the beam spread and beam wander characteristics of fractional-order vortex beams with those of integer-order vortex beams after passing through a turbulent atmosphere simulator with varying turbulence intensities. Our results revealed that the beam spread of both fractional-order and integer-order vortex beams increased in a stepwise manner with the topological charge number, indicating that a larger topological charge number resulted in more severe beam spread. Interestingly, we observed that the beam radius of fractional-order vortex beams between two adjacent integer orders initially grew slowly and then rapidly before finally stabilizing into a curvilinear growth trend. This is in contrast to the linear growth trend exhibited by the beam radius of integer-order vortex beams. Furthermore, we found that the growth of the beam radius of half-integer-order vortex beams followed the linear growth trend of the beam radius of integer-order vortex beams. When the integer part of the topological charge was fixed, we observed that stronger turbulence resulted in more severe beam wander for both integer-order and fractional-order vortex beams, with the variance of the center-of-mass drift following the same growth curve. However, when the turbulence intensity is constant, both integer-order and fractional-order vortex beams exhibit a weaker beam wander effect with increasing topological charge. Our findings may provide valuable insights for applications such as optical communication and optical measurement using fractional-order vortex beams.

Magnetic Resonance Imaging Manifestations of Annular Ligament Injuries in Children With Monteggia Fractures.

Magnetic resonance imaging (MRI) is commonly performed in children with elbow injuries to visualize soft tissues such as the annular ligament. Herein, we investigated the MRI manifestations of annular ligament injuries in children with Monteggia fractures following attempted closed reduction. The clinical and imaging data of 88 children with acute Monteggia fractures treated at our hospital between 2015 and 2019 were analyzed. Clinically and radiographically, 67 patients achieved radiologic reduction of the radial head at the time of MRI, whereas 21 patients had a failed closed reduction. Annular ligament injury and superior radioulnar joint congruency were analyzed qualitatively, and the maximum superior radioulnar joint gap distance was measured. MRI manifestations of annular ligament injury were primarily characterized as varying degrees of annular ligament displacement, as follows: I degree (10 patients), the annular ligament encircled the radial head without displacement; II degree (5 patients), the annular ligament was partially displaced but visibly encircled the radial head at the level of the radial notch; and III degree (73 patients), the annular ligament was completely displaced. In 15 patients with I and II degrees annular ligament injuries, the annular ligament encircled the radial head (maximum superior radioulnar joint gap distance, 1.2±0.3mm), showing good congruency of the superior radioulnar joint. In 73 patients with III degree annular ligament injury, the annular ligament was displaced and did not encircle the radial head (maximum superior radioulnar joint gap distance, 3.3±2.7mm; P <0.05), showing good congruency of the superior radioulnar joint in 25 of 73 patients, and significantly poor congruency in 48 of 73 patients ( P <0.05). Annular ligament injuries in children with Monteggia fractures exhibit different degrees of displacement of the annular ligament. In I and II degree annular ligament injuries, the annular ligament still encircles the radial head. In III degree annular ligament injuries, the annular ligament is displaced away and is no longer around the radial head. Without the annular ligament restraining the radial head, the superior radioulnar joint is more likely to exhibit poor congruency and increased gap distance. Level II.

Uncovering the adult morphology of the forearm bones from the Sima de los Huesos Site in Atapuerca (Spain), with comments on biomechanical features.

The forearm skeleton is composed of two bones: the radius and the ulna. This is closely related to manipulative movements. The ulna is part of the elbow joint, whereas the radius and ulna together with the scaphoid and lunate bones, form the wrist joints. Thus, morphofunctional analysis of the adult Sima de los Huesos (SH) forearm bones, provides clues about manipulative activities in one Pleistocene population. From 1976 to the present, over 7000 human fossils have been recovered from the SH site. The radial sample comprised 98 labeled fragments, of which 49 belonged to adult individuals, representing at least 7 individuals. The ulnar sample included 31 labeled adult fossils representing at least nine individuals. In this study, we describe the SH radii and ulnae and analyze their functional implications for manipulative and forearm movements. We confirmed that the SH radii are long and curved, with variations in robusticity and radial tuberosity orientation. The SH ulnae are characterized by an anteriorly oriented trochlear notch, a massive olecranon process, an obliquely oriented radial notch, a blunt and short supinator crest, a gracile and curved diaphysis, and a round and anteriorly oriented pronator crests. In general, they exhibit Neanderthal morphology. The SH collection provides a unique opportunity to conduct morphological analyses of these bones in the Middle Pleistocene population.

Estimation of Fatigue Limit and Strength Degradation Mechanism of a High Strength Steel in Petrol Environment by Means of a Small Sized Specimen with Radial Notch

Strength of structural materials used in corrosive environment will be lowered compared with that of materials used in air due to the effect of corrosion fatigue. In the previous study, fatigue tests on a type 440C stainless steel, which has been used as a part of automobile fuel injection system, in air and petrol environment were conducted by means of a small sized smooth specimen and a fatigue testing machine for the specimen performable in corrosion and flammable liquid under push-pull loading at high frequency region. However, it was difficult to investigate the effect of corrosion due to the difference of fracture morphology. In this study, fatigue tests on the same material were conducted by means of a small sized specimen with notch for matched fracture origin in air and deteriorated petrol under the same test condition. The fracture on fatigue tests with notched specimens initiated from specimen surface regardless of the test environment. In petrol that contains methanol, fatigue fracture was caused on lower stress level because minor intergranular cracks were originated by the effect of corrosion. Fatigue lives of flat specimen were correlated using the size of the inclusions and they were correlated with high accuracy. Fatigue limit was also estimated. It was confirmed that fracture origin was changed to the surface due to immersion to petrol that contains methanol. The relationship with the stress state in notch part and fatigue failure mechanism was discussed in detail.

Distal Radioulnar Joint: Normal Anatomy, Imaging of Common Disorders, and Injury Classification.

The distal radioulnar joint (DRUJ) is the distal articulation between the radius and ulna, acting as a major weight-bearing joint at the wrist and distributing forces across the forearm bones. The articulating surfaces are the radial sigmoid notch and ulnar head, while the ulnar fovea serves as a critical attachment site for multiple capsuloligamentous structures. The DRUJ is an inherently unstable joint, relying heavily on intrinsic and extrinsic soft-tissue stabilizers. The triangular fibrocartilage complex (TFCC) is the chief stabilizer, composed of the central disk, distal radioulnar ligaments, ulnocarpal ligaments, extensor carpi ulnaris tendon subsheath, and ulnomeniscal homologue. TFCC lesions are traditionally classified into traumatic or degenerative on the basis of the Palmer classification. The novel Atzei classification is promising, correlating clinical, radiologic, and arthroscopic findings while providing a therapeutic algorithm. The interosseous membrane and pronator quadratus are extrinsic stabilizers that offer a minor contribution to the joint's stability in conjunction with the joints of the wrist and elbow. Traumatic and overuse or degenerative disorders are the most common causes of DRUJ dysfunction, although inflammatory and developmental abnormalities also occur. Radiography and CT are used to evaluate the integrity of the osseous constituents and joint alignment. US is a useful screening tool for synovitis in the setting of TFCC tears and offers dynamic capabilities for detecting tendon instability. MRI allows simultaneous osseous and soft-tissue evaluation and is not operator dependent. Arthrographic CT or MRI provides a more detailed assessment of the TFCC, which aids in treatment and surgical decision making. The authors review the pertinent anatomy and imaging considerations and illustrate common disorders affecting the DRUJ. Online supplemental material is available for this article. © RSNA, 2022.

Morphological and radiological study of the shoulder and elbow joints of the giant anteater (Myrmecophaga tridactyla).

The giant anteater (Myrmecophaga tridactyla) has specialized thoracic limbs to forage by breaking the walls of anthills and termite mounds. They also play critical roles in defense posture and locomotion. This study aimed to provide a morphological and radiographic description of the shoulder joint and elbow joint of the giant anteater. Both joints of 13 tamanduas were assessed by morphological dissections and histological evaluation and radiographies without and with positive contrast. The radiographic projections selected to this study were the mediolateral and craniocaudal projections. The radiographic and anatomical findings were compared with the following results: the shoulder joint had a continuous joint capsule with the tendon sheaths of the short head and long head of the biceps brachii muscle, which could be visualized with an injection of 3 ml of intra-articular contrast. The shoulder joint arthrography was performed with the needle positioned cranially to the joint for contrast injection. The elbow joint presented three articular compartments, and the insertion of the joint capsule was proximal to the radial fossa and distal to the radial tuberosity in the radial notch of the ulna, which were possible to identify with 2 ml of intra-articular contrast. The elbow joint arthrography was performed with the needle positioned laterally to the joint for contrast injection. Moreover, the joint capsule presented a caudomedial distention and fat pads. The powerful muscles of the forelimb play a fundamental role in maintaining the shoulder joint and elbow joint stability due to bony adaptations and the absence of usual ligaments. The morphological and radiological study provided relevant information on the soft-tissue characteristics of shoulder and elbow joints, which may aid clinical-surgical and diagnostic imaging procedures.

Missed Monteggia fractures in children treated by open reduction of the radial head and corrective osteotomy of the ulna

Missed Monteggia fractures in children may cause pain, deformity, decreased range of motion, neurological symptoms, and late arthritis of the elbow. Numerous surgical techniques have been advocated to reconstruct missed Monteggia lesions. The purpose of the present study were first to evaluate the clinical and radiographic outcomes after open reduction of the radial head and corrective osteotomy of the ulna, second to identify the factors associated with the preoperative radial notch/head appearance and the postoperative radiographic results. This study investigated the preoperative MRI presentation and the treatment of 29 patients who were diagnosed missed Monteggia fracture. Radiologic and clinical results of these patients were evaluated retrospectively, and the patient’s and surgical factors related to preoperative radial notch/head appearance and the postoperative radiographic results were analyzed. Of the 29 patients, the average Kim elbow performance score at the last follow-up was 93.6, with 25 excellent, three good, one fair, and no poor results. 19 children had reduced radial heads, 8 had a subluxated radial head and 2 had dislocated radial heads at the last follow-up. The patient’s gender and age had no significant influence on the appearance of radial notch/head and final radiographic results. However, the appearance of radial notch/head can significantly affect the final radiographic result (P < 0.001). The interval time was an important factor which related with the appearance of radial notch/head and final radiographic results (P < 0.001). Treating a missed Monteggia fracture by open reduction of the radial head and corrective osteotomy of the ulna is generally successful and preoperative MRI is meaningful for evaluation of the condition of the radial head and the radial notch which is related with the final radiographic result. The interval time from injury to operation exceeds 6 months, the risk of radial notch/head abnormality and radial head subluxation/re-dislocation after operation significantly increase.

Ulna’nın Proksimal Bölümünün Anatomik Yapısı

Amaç: Ulna’nın proksimal bölümü'nün şekli, kırıkların stabilizasyonunu ve cerrahi sonrası fonksiyonların rehabilitasyonunu etkileyen unsurlardan birisidir. Redüksiyon sırasında normal anatomik yapılanma sağlanamaz ise bu durum eklemin çıkıklarına, artritine ve fonksiyon kaybına neden olabilir. Redüksiyonun tam olarak gerçekleştirilemediği ufak parçalı kırıklarda ise uygun bir plak yardımı ile anatomik yapılanma desteklenebilir. Plak kullanımının gerektiği durumlarda ise ulna’nın proksimal bölümü yapısının detaylı bilinmesi önemlidir.Materyal ve metod: Bu çalışma, Necmettin Erbakan Üniversitesi, Meram Tıp Fakültesi, Anatomi Anabilim Dalı’na ait kemik koleksiyonundaki 62 (cinsiyetleri belirsiz, 26 sağ ve 36 sol ulna) adet ulna üzerinde gerçekleştirildi. Çalışmamızda ulna'nın proksimal bölümü'ne ait uzunluk ve genişlik ölçümleri ile birlikte açı ölçümleri gerçekleştirilmiştir.Bulgular: Çalışmamızda toplam ulna uzunluğu (UU) ortalama 24.59±2.00 cm olarak belirlenmiştir. Inc. radialis yükseklik (IRY) ve genişlik (IRG) ölçümleri tüm ulna’larda ortalama olarak sırasıyla 9.69±1.64 mm ve 15.22±2.18 mm olarak belirlenmiştir. Inc. trochlearis derinliğinin (ITD) ise 7.30 ile 13.70 mm (ortalama 10.15 mm) arasında değişkenlik gösterdiği belirlenmiştir. Tüm ulna’larda ortalama ulna’nın proksimal bölümü torsiyon açısı (PUTA), varus açısı (VA), artiküler açı (AA), ulna’nın proksimal bölümü dorsal açısı (PUDA), tüberkül açısı (TA), olecranon-diyafiz açısı (ODA) sırasıyla 13.40±1.230, 9.20±1.850, 20.37±1.020, 5.85±2.210, 18.99±0.830, 15.49±3.100 olarak belirlenmiştir.Sonuç: Bireysel farklılıkların göz önüne alınarak tasarlandığı implant ve protezler dirsek eklemindeki uyumun başarı oranını arttırmakta ve eklemin fonksiyonunu düzgün olarak yerine getirilmesini sağlamak-tadır.

High-Resolution Ultrasonographic Anatomy of the Carpal Tendons of Sporting Border Collies.

Simple SummaryDog agility is a canine sport that has gained popularity among pet owners in recent decades. Because of the high-performance level, injuries to dogs competing in this sport are becoming frequent. The need for better knowledge of the anatomy of the structures involved in athletic movements is an essential starting point for correctly managing agility-related injuries. The aim of this paper was to investigate the ultrasonographic anatomy of the carpal joint, creating a baseline reference for the Border Collie, which is the breed most utilised in agility competitions. The data acquired could be of use in future studies regarding sport-induced injuries in the canine carpus.Recent literature has demonstrated that high-resolution ultrasonographic anatomy of the canine carpus is possible; however, only the structures of the dorsal face were described. The aims of this prospective study were: (1) to describe the normal ultrasonographic appearance of the carpal tendons in sporting Border Collies; (2) to measure the height, length, and thickness of the tendon at the radial ulnar notch level in order to create a baseline reference for the breed, and (3) to describe a standardised protocol to ultrasonographically evaluate the carpal faces and visible tendinous structures. A pilot study based on ten cadaveric front limbs was used to identify the structures. A subsequent clinical phase of the study using twenty-six Border Collies was recorded. The tendons of the Extensor Carpi Radialis, Extensor Digitorum Communis, and Extensor Digitorum Lateralis were identified and followed from the tenomuscular junction to the distal insertion on the dorsal face of the digits. On the lateral face, the tendon of the Extensor Carpi Ulnaris was recognised and followed. On the palmar face, the two heads of the Flexor Carpi Ulnaris tendon ending on the accessory carpal bone, the adjacent Flexor Digitorum Superficialis tendon, and the deep and medially located Flexor Digitorum Profundus tendon were seen and followed. The Flexor Carpi Radialis and the Abductor Pollicis Longus tendons were seen in the medial carpal face. The ulnar notch of the radius was used as the measurement and starting point of the ultrasonography. These data could be used as a standard reference in the case of chronic overuse and trauma-induced changes in the canine carpus.

Fatigue Analysis and Defect Size Evaluation of Filled NBR including Temperature Influence.

The fatigue behavior of a filled non-crystallizing elastomer was investigated on axisymmetric dumbbell specimens. By plotting relevant Wöhler curves, a power law behavior was found. In addition, temperature increases due to heat build-up were monitored. In order to distinguish between initiation and crack growth regimes, hysteresis curves, secant and dynamic moduli, dissipated and stored energies, and normalized minimum and maximum forces were analyzed. Even though indications related to material damaging were observed, a clear trend to recognize the initiation was not evident. Further details were revealed by considering a fracture mechanics. The analysis of the fracture surfaces evidenced the presence of three regions, associated to initiation, fatigue striation, and catastrophic failure. Additional fatigue tests were performed with samples in which a radial notch was introduced. This resulted in a reduction in lifetime by four orders of magnitude; nevertheless, the fracture surfaces revealed similar failure mechanisms. A fracture mechanics approach, which considered the effect of temperature, was adopted to calculate the critical defect size for fatigue, which was found to be approximately 9 μm. This value was then compared with the particle size distribution obtained through X-ray microcomputed tomography (μ-CT) of undamaged samples and it was found that the majority of the initial defects were indeed smaller than the calculated one. Finally, the evaluation of J-integral for both unnotched and notched dumbbells enabled the assessment of a geometry-independent correlation with fatigue life.

Lateral Ulnar Collateral Ligament of the Elbow Joint: Reconsideration of Anatomy in Terms of Connection with Surrounding Fibrous Structures.

To improve the clinical results of lateral ulnar collateral ligament (LUCL) reconstruction of the elbow joint, better understanding of the anatomy of the aponeuroses and joint capsule could be relevant. This study considers the previously described anatomy of the LUCL in relation to the related aponeuroses and joint capsule rather than as a discrete ligament. We hypothesized that the deep aponeuroses of the superficial extensor muscles and supinator form a relevant portion of the joint capsule previously defined as the LUCL. Twenty-four elbows (12 right) from 21 embalmed cadavers (age at the time of death, 54 to 99 years) were included in the study. Twenty elbows were studied macroscopically and 4, histologically. The joint capsule was detached from the bones, and local thickness was quantitatively analyzed using micro-computed tomography (micro-CT). The supinator aponeurosis and joint capsule intermingled to form a thick membrane (mean and standard deviation, 4.8 ± 1.2 mm), which we termed "the capsulo-aponeurotic membrane." It was thicker than the anterior (1.3 ± 0.4 mm) and posterior (2.5 ± 0.9 mm) parts of the capsule of the humeroradial joint (p < 0.001). The capsulo-aponeurotic membrane had a wide attachment on the distal part of the extensor digitorum communis and extensor digiti minimi (EDC/EDM) origin of the humerus, the lateral part of the coronoid process, and the posterior part of the radial notch of the ulna. The humeral attachment had a fibrocartilaginous structure. The deep aponeuroses of the EDC and extensor carpi ulnaris (ECU) were connected to the capsulo-aponeurotic membrane. The capsulo-aponeurotic membrane was composed of the supinator aponeurosis and joint capsule and was attached to the lateral epicondyle of the humerus, radial side of the coronoid process, and posterior part of the radial notch on the ulna. The entire structure appeared identical to the commonly defined lateral collateral ligament. The most posterior part was connected to the EDC and ECU aponeuroses, which is commonly labeled the LUCL but does not exist as a discrete ligament. Consideration of the accurate anatomy of the extensive attachment of the capsulo-aponeurotic membrane could provide useful clues for improvement in techniques of LUCL reconstruction and lateral epicondylitis pathology.

Morphological affinities of a fossil ulna (KNM-WS 65401) from Buluk, Kenya

The morphological affinities of a primate proximal ulna (KNM-WS 65401) recovered from the late Early Miocene site Buluk, Kenya, are appraised. Nineteen three-dimensional landmarks on ulnae from 36 extant anthropoid species (n = 152 individuals) and KNM-WS 65401, as well as a subset of 14 landmarks on six ulnae belonging to other East African Miocene catarrhine taxa, were collected. To quantify ulnar shape, three-dimensional geometric morphometric techniques were used and linear dimensions commonly cited in the literature were derived from the landmark data. KNM-WS 65401 is situated between monkeys and hominoids in the principal components morphospace. KNM-WS 65401 shares features such as a short olecranon process, broad trochlear notch, and laterally oriented radial notch with extant hominoids, whereas features such as an anteriorly directed trochlear notch and flat, proximodistally elongated, and anteroposteriorly narrow radial notch are shared with extant monkeys. Principal component scores and linear metrics generally align KNM-WS 65401 with both suspensors and arboreal quadrupeds, but quadratic and linear discriminant analyses of principal component score data provide posterior probabilities of 80% and 83%, respectively, for assignment of KNM-WS 65401 to the suspensory group. Compared with fossil ulnae from other Miocene primates, KNM-WS 65401 is morphologically most distinct from KNM-LG 6, attributed to Dendropithecus macinnesi, and morphologically most similar to KNM-WK 16950R, attributed to Turkanapithecus kalakolensis. The KNM-WS 65401 individual likely possessed more enhanced capabilities for elbow joint extension, perhaps during suspensory behaviors, compared with other Miocene primates in the sample.

Intensity interference characteristics of fractional Laguerre–Gaussian optical vortex

The paper reports the intensity characteristics of fractional vortex beam, and controls the coupling between photon orbital angular momentum and spin angular momentum by coherently manipulating Laguerre–Gaussian vortex beam with linearly polarized plane light and its conjugate beam. By comparing theory with experiment, fractional vortex beams with different topological charges are generated by using pure phase liquid crystal spatial light modulator, and their intensity characteristics and interference characteristics are observed. The results show that the radial notch size of the spot is related to the fractional part of the topological charge value, and the closer the fractional part of the topological charge value is to the half integer, the more obvious the radial notch is. With the increase of integer part of topological charge, the spot radius also increases. In addition, interference with linearly polarized plane light reveals that the number of branches is equal to the number of topological charges. Interfere with its conjugate beam, and judge the topological charge number of vortex beam by the relationship between petal number and topological charge number. The petal number of integer vortex beam is twice the topological charge number, and fractional order vortex beam destroys the ring structure of Laguerre–Gaussian beam.

Standard radiographic assessments of distal radius fractures miss involvement of the distal radioulnar joint: a diagnostic study

IntroductionDistal radius fractures account for one-fifth of all fractures in the emergency department. Their classification based on standard radiographs is common practice although low inter-observer reliabilities and superiority of computer tomography (CT) scanning in evaluation of joint congruency have been reported.Materials and methodsWe retrospectively analyzed 96 displaced distal radius fractures scheduled for open reduction and internal fixation using standard radiographic assessment. The radiographs were classified with the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA), Fernandez and Frykman classifications by three observers and inter-rater reliabilities were calculated. Additional CT scanning was performed in all cases and the following parameters were assessed: radiocarpal joint involvement, fracture extent into the radial sigmoid notch, i.e. the distal radio-ulnar joint, comminution of the metaphysis, and concomitant ulnar styloid fracture. The CT scans were used as a reference standard to determine sensitivity and accuracy of standard radiographic assessment in evaluation of distal radius fractures.ResultsThe inter-rater agreement for the AO classification was 35.4%, 68.8% for the Fernandez and 38.5% for the Frykman classification. Fracture extension into the radiocarpal joint was present in 81 cases (84.4%). Sigmoid notch involvement was found in 81 fractures (84.4%). Involvement of both joints was present in 72 cases (75%). The sensitivity of standard radiographs regarding radiocarpal joint involvement was 93.8%. Considering involvement of the distal radio-ulnar joint the false-negative rate using standard radiographs was 61.7% and the test’s accuracy for sigmoid notch involvement was 45.8%.ConclusionThis study demonstrates that involvement of the sigmoid notch is frequently missed in standard radiographs. The presented data support the frequent use of CT imaging to allow the holistic illustration of a fracture’s complexion and to ensure optimal pre-operative planning.

Biomechanics of the Distal Radioulnar Joint During In Vivo Forearm Pronosupination.

Background Ulnar variance (UV) and center of rotation (COR) location at the level of the distal radioulnar joint (DRUJ) change with forearm rotation. Nevertheless, these parameters have not been assessed dynamically during active in vivo pronosupination. This assessment could help us to improve our diagnosis and treatment strategies. Questions/purposes We sought to (1) mathematically model the UV change, and (2) determine the dynamic COR's location during active pronosupination. Methods We used biplanar videoradiography to study DRUJ during in vivo pronation and supination in nine healthy subjects. UV was defined as the proximal-distal distance of ulnar fovea with respect to the radial sigmoid notch, and COR was calculated using helical axis of motion parameters. The continuous change of UV was evaluated using a generalized linear regression model. Results A second-degree polynomial with R 2 of 0.85 was able to model the UV changes. Maximum negative UV occurred at 38.0 degrees supination and maximum positive UV occurred at maximum pronation. At maximum pronation, the COR was located 0.5 ± 1.8 mm ulnarly and 0.6 ± 0.8 mm volarly from the center of the ulnar fovea, while at maximum supination, the COR was located 0.2 ± 0.6 mm radially and 2.0 ± 0.5 mm volarly. Conclusion Changes in UV and volar translation of the COR are nonlinear at the DRUJ during pronosupination. Clinical Relevance Understanding the dynamic nature of UV as a function of pronosupination can help guide accurate evaluation and treatment of wrist pathology where the UV is an important consideration. The dynamic behavior of COR might be useful in designing DRUJ replacement implants to match the anatomical motion.

The prevalence of Vickers' ligament in Madelung's deformity: a retrospective multicentre study of 75 surgical cases.

In a retrospective multicentre study, we aimed to correlate clinical factors and findings on plain radiographs and MRI with the intraoperative presence of Vickers’ ligament in Madelung’s deformity. We screened the records, in which the absence or presence of Vickers’ ligament was affirmatively indicated, of 75 consecutive operated extremities in 58 patients. In 83% a Vickers’ ligament was observed intraoperatively. The whole bone Madelung type (as opposed to the distal type) and a distal radial notch were independent, significant predictors for the presence of the ligament. The correct Vickers detection rate using MRI was 85% of the 27 cases for which MRI was available. Thus, the MRI was a good but not perfectly reliable modality. We conclude that Vickers’ ligament is present in the majority but not all cases with Madelung deformity. We advise that patients with a more severe type of Madelung’s deformity and a distal radial notch should be monitored closely.Level of evidence: IV

Development of a test method to investigate mode II fracture and dissection of arteries

The current study presents the development and implementation of a bespoke experimental technique to generate and characterise mode II crack initiation and propagation in arterial tissue. The current study begins with a demonstration that lap-shear testing of arterial tissue results in mixed mode fracture, rather than mode II. We perform a detailed computational design of a bespoke experimental method (which we refer to as a shear fracture ring test (SFRT)) to robustly and repeatably generate mode II crack initiation and propagation in arteries. This method is based on generating a localised region of high shear adjacent to a cylindrical loading bar. Placement of a radial notch in this region of high shear stress is predicted to result in a kinking of the crack during a mode II initiation and propagation of the crack over a long distance in the circumferential (c)-direction along the circumferential-axial (c-a) plane. Fabrication and experimental implementation of the SFRT on excised ovine aorta specimens confirms that the bespoke test method results in pure mode II initiation and propagation. We demonstrate that the mode II fracture strength along the c-a plane is eight times higher than the corresponding mode I strength determined from a standard peel test. We also calibrate the mode II fracture energy based on our measurement of crack propagation rates. The mechanisms of fracture uncovered in the current study, along with our quantification of mode II fracture properties have significant implications for current understanding of the biomechanical conditions underlying aortic dissection.