Relationship between talofibular impingement and increased talar tilt in incongruent varus ankle osteoarthritis

Purpose This study aimed to evaluate the relationship between talofibular impingement and increased talar tilt in incongruent varus ankle osteoarthritis. Methods: Incongruent varus ankle osteoarthritis was defined as a talar tilt of more than 4° on standard ankle anteroposterior radiographs. We retrospectively reviewed 30 patients with unilateral incongruent varus ankle osteoarthritis with normal alignment of the contralateral ankle. All patients underwent bilateral weightbearing computed tomography and standing plain radiographs. The talar tilt and the distance between the talar lateral process and lateral malleolar tip were measured from a standing ankle anteroposterior radiograph of both sides. Talar and fibular spurs were assessed on the coronal and axial views of weightbearing computed tomography. After simulating the correction of the talar tilt in varus ankle osteoarthritis, talofibular bony impingement was reassessed. Results: On the varus side, the distance between the talar lateral process and the lateral malleolar tip was significantly shorter than that on the contralateral side ( p < .001). Talar spur was present in the varus side of all 30 patients on the axial view of weightbearing computed tomography and in the control side of 10 patients. After the simulation of talar tilt correction, talofibular impingement (overlap) occurred in all 30 patients with a larger extent in the severe talar tilt subgroup ( p < .001). Conclusion: Talofibular impingement by lateral gutter osteophytes is closely related to increased talar tilt in patients with incongruent varus ankle osteoarthritis. Therefore, lateral gutter osteophytes should be resected to stabilize mortise and improve clinical outcomes.

Muvi schmallenbergi gen. nov., sp. nov. (Crustacea, Tanaidacea) from the southeast Australian coast, with comments on the distribution and habitat preferences of Chondropodinae

Based on material collected from the shelf off southeast Australia (offshore of Portland), a new genus and new species, Muvi schmallenbergi gen. nov., sp. nov., of the tanaidacean family Metapseudidae, is described. Muvi is distinguishable from other genera within the subfamily Chondropodinae by having equally long antennular flagella. It also differs from other Chondropodinae by a combination of characters such as eyelobes with a group of visual elements, rostrum with smooth lateral edges, pereonites with lateral processes and pleotelson lacking lateral process, antennule article-1 with a single apophysis, maxillule inner lobe well-developed, labial palp bearing three distal setae, cheliped exopod well-developed and setose, pereopod-1 coxa with distinct apophysis, pleopods in five pairs, and uropod basis without apophysis. The genus Deidamiapseudes Sganga & Roccatagliata, 2016 is moved from Chondropodinae (Metapseudidae) to Apseudoidea incertae sedis. An identification key for the genera within Chondropodinae is given, and their distribution is discussed.

New Classification Based on CT and Its Value Evaluation for Fractures of the Lateral Process of the Talus

Background : The common classifications of the fractures of the lateral process of the talus（LTPFs）are based on radiographs and may underestimate the complexity of LTPF, therefore. The aim of this study was to propose a comprehensive CT-based classification system, and to evaluate its prognostic value, reliability and reproducibility.Material and Methods: We retrospectively reviewed 42 patients involving LTPF and clinical and radiographic evaluations were performed at an average follow-up of 35.9 months. In order to create a comprehensive classification, a panel of experienced orthopedic surgeons discussed the cases. All fractures were classified according to Hawkins, McCrory-Bladin and new proposed classification system by four surgeons. The analysis of interobserver and intraobserver agreements was done using kappa statistics.Results: This new classification included two types based on presence of concomitant injuries or not, with type I consisting of three subtypes and type II of five subtypes. Average AOFAS score was 91.5 in the type Ia of new classification proposed, 86 in type Ib, 90.5 in type Ic, 89 in type IIa, 76.7 in type IIb, 76.6 in type IIc, 91.3 in type IId, and 83.5 in type IIe. Interobserver and intraobserver reliability of the new classification system were almost perfect (κ=0.846 and 0.823, respectively)，showing a higher interobserver and intraobserver reliability compared to the Hawkins classification (κ=0.737 and 0.689, respectively) as well as McCrory-Bladin classification (κ=0.748 and 0.714, respectively). Conclusion: The new classification system is a comprehensive one that takes into account concomitant injuries and it shows good prognostic value with clinical outcomes. It is more reliable and reproducible and could be a useful tool for decision-making on treatment options for LTPFs.

The postcranial skeleton of Cerrejonisuchus improcerus (Crocodyliformes: Dyrosauridae) and the unusual anatomy of dyrosaurids

Dyrosauridae is a clade of neosuchian crocodyliforms that diversified in terrestrial and aquatic environments across the Cretaceous-Paleogene transition. The postcranial anatomy of dyrosaurids has long been overlooked, obscuring both their disparity and their locomotive adaptations. Here we thoroughly describe of the postcranial remains of an unusually small dyrosaurid, Cerrejonisuchus improcerus, from the middle-late Paleocene Cerrejón Formation of Colombia, and we provide a wealth of new data concerning the postcranial anatomy of the key dyrosaurids: Congosaurus bequaerti and Hyposaurus rogersii. We identify a series of postcranial autapomorphies in Cerrejonisuchus improcerus (an elliptic-shaped odontoid laterally wide, a ulna possessing a double concavity, a fibula bearing a widely flattened proximal end, a pubis showing a large non-triangular distal surface) as well as functionally-important traits such as a relatively long ulna (85% of the humerus’ length), short forelimb (83% of hindlimb’s length), or thoracic vertebra bearing comparatively large lateral process (with widened parapophysis and diapophysis) along with strongly arched thoracic ribs allowing a more sturdy and cylindrical rib cage. These indicate a more terrestrial lifestyle for Cerrejonisuchus compared to the derived members of the clade. We also built a dataset of 187 traits on 27 taxa, that extensively samples the cranial and postcranial architectures of exemplar crocodyliforms. We analyze these data in via Principal Coordinate Analysis (PCoA) to visualize the postcranial morphospace occupation of Dyrosauridae, Thalattosuchia, and Crocodylia. Our data reveal the existence of a distinctive postcranial anatomy for Dyrosauridae that is markedly distinct from that of crocodylians. As a result, modern crocodylians are probably not good functional analog for extinct crocodyliformes. Postcranial data should also be more widely used in phylogenetic and disparity analyses of Crocodyliformes.

Fractures of the Lateral Process of the Talus: A New Classification Based on CT

Background: The common classifications of the fractures of the lateral process of the talus（LTPFs）are based on radiographs and may underestimate the complexity of LTPF, therefore, requiring a comprehensive classification based on CT(Computed tomography) scan. The aim of this study is to propose a such classification system, and to evaluate its reliability and reproducibility.Methods: On the basis of the most widely recognized classifications of Hawkins as well as McCrory-Bladin, we proposed a new and comprehensive classification based on CT scan for the LTPF. We retrospectively reviewed 42 patients involving LTPF. All fractures were classified according to Hawkins, McCrory-Bladin and new proposed classification system by three surgeons. The analysis of interobserver and intraobserver agreements was done using kappa statistics.Results: This new classification included two types based on presence of concomitant injuries or not, with type I consisting of three subtypes and type II of five subtypes. Interobserver and intraobserver reliability of the new classification system were almost perfect (κ=0.846 and 0.823, respectively)，showing a higher interobserver and intraobserver reliability compared to the Hawkins classification (κ=0.737 and 0.689, respectively) as well as McCrory-Bladin classification (κ=0.748 and 0.714, respectively). Conclusion: This new classification system for the LTPF based on CT is a comprehensive classification considering concomitant injuries. It is more reliable and reproducible and can potentially become a useful instrument for decision making of treatment options for LTPFs. Further studies on the evaluation of their clinical relevance (especially the long-term outcome) are warranted.

Osteochondritis Dissecans of Lateral Process of Talus Involving the Subtalar Joint: An Unusual Case

Osteochondral dissecans (OCD)of talus is an uncommon injury is often missed initially. We reported a rare case of OCD of the lateral process of talus involving the subtalar joint in a 34-year-old male. Magnetic resonance imaging exhibited degenerative changes at the subtalar joint, with a 12 × 10 × 15-mm subchondral cystic lesion within the lateral part of talus in the posterior subtalar joint and two osseous loose bodies in the lateral compartment, which were removed through the sinus tarsi approach. A 1.2 × 1.5-cm osteochondral fragment distal to the lateral process of talus was noted intraoperatively. The subchondral cyst was excised and the fragment fixed with a 4-mm partially-threaded cannulated cancellous screw. The foot and ankle disability score improved from 26.0 preoperatively to 92.3 at the 1-year follow-up. Thus, talus OCD is an unusual condition that mandates a thorough clinical and radiological work-up and prompt management.