Posterior Fragment Research Articles

Understanding the mechanism of injury and fracture pattern of paediatric triplane ankle fractures versus adult trimalleolar fractures.

Paediatric triplane fractures and adult trimalleolar ankle fractures both arise from a supination external rotation injury. By relating the experience of adult to paediatric fractures, clarification has been sought on the sequence of injury, ligament involvement, and fracture pattern of triplane fractures. This study explores the similarities between triplane and trimalleolar fractures for each stage of the Lauge-Hansen classification, with the aim of aiding reduction and fixation techniques. Imaging data of 83 paediatric patients with triplane fractures and 100 adult patients with trimalleolar fractures were collected, and their fracture morphology was compared using fracture maps. Visual fracture maps were assessed, classified, and compared with each other, to establish the progression of injury according to the Lauge-Hansen classification. Four stages of injury in triplane fractures, resembling the adult supination external rotation Lauge-Hansen stages, were observed. Stage I consists of rupture of the anterior syndesmosis or small avulsion of the anterolateral tibia in trimalleolar fractures, and the avulsion of a larger Tillaux fragment in triplanes. Stage II is defined as oblique fracturing of the fibula at the level of the syndesmosis, present in all trimalleolar fractures and in 30% (25/83) of triplane fractures. Stage III is the fracturing of the posterior malleolus. In trimalleolar fractures, the different Haraguchi types can be discerned. In triplane fractures, the delineation of the posterior fragment has a wave-like shape, which is part of the characteristic Y-pattern of triplane fractures, originating from the Tillaux fragment. Stage IV represents a fracture of the medial malleolus, which is highly variable in both the trimalleolar and triplane fractures. The paediatric triplane and adult trimalleolar fractures share common features according to the Lauge-Hansen classification. This highlights that the adolescent injury arises from a combination of ligament traction and a growth plate in the process of closing. With this knowledge, a specific sequence of reduction and optimal screw positions are recommended.

In silico comparative biomechanical analysis of oblique and chevron medial displacement calcaneal osteotomies for pes planus deformity

BackgroundMedializing displacement calcaneal osteotomy is commonly performed as part of reconstructive surgery for patients with valgus hindfoot and progressive pes planus deformity. Among several types of calcaneal osteotomies, the oblique and Chevron osteotomy patterns have been commonly described in the literature and gained popularity as they are easily reproducible through percutaneous techniques. Currently, there is scarce evidence in the literature on which cut pattern is superior in terms of stability. To investigate the impact of cut pattern and posterior fragment medialization level on foot biomechanics, computational methods are employed. MethodsAnkle weightbearing computer tomography (CT) scans of seven patients diagnosed with stage II pes planus deformity are segmented and converted into 3D computational models. Oblique and Chevron osteotomy patterns are modeled independently for each patient. The posterior fragments are medially translated by 8-, 10- and 12-mm and subsequently fixated to the anterior calcaneus with two screws. A total of 42 models are exported to finite element software for biomechanical simulations. Among the investigated parameters, the higher stiffness and lower von Mises stress at the osteotomy interface and the screw site are assumed to be precursors of better stability. ResultsIt is recorded that as the medialization level increases, the stiffness decreases, and overall stresses increase. Also, it is observed that the Chevron cut produces a stiffer construct while the overall stresses are lower, indicating better stability when compared to the oblique cut. The statistical comparisons of the relevant groups that support these trends are found to be significant (p < 0.05). ConclusionChevron osteotomy showed superior stability compared to the oblique osteotomy while underscoring the negative impact of increased medialization of the posterior fragment. Clinical relevanceOpting for a lower medialization level and implementing the Chevron technique may facilitate union and earlier weightbearing.

Injury to the posterior malleolus in Maisonneuve fractures

PurposeThe aim of this study was to describe the incidence and a complex pathoanatomy of posterior malleolus fractures in a Maisonneuve fracture.MethodsThe study included 100 prospectively collected patients with a complete clinical and radiological documentation of an ankle fracture or fracture-dislocation including a fracture of the proximal quarter of the fibula.ResultsA posterior malleolus fracture was identified in 74 patients, and in 27% of these cases it carried more than one quarter of the fibular notch. Displacement of the posterior fragment by more than 2 mm was shown by scans in 72% of cases. Small intercalary fragments were identified in 43% of cases. Fractures of the Tillaux–Chaput tubercle were identified in 20 patients.ConclusionOur study has proved a high rate of posterior malleolus fractures associated with a Maisonneuve fracture, and documented their considerable variability in terms of involvement of the fibular notch, tibiotalar contact area, direction of displacement and frequency of intercalary fragments. Of no less importance is a combination of Tillaux–Chaput fractures with a Maisonneuve fracture.

Syndesmosis Injuries in Lateral Malleolar Fractures Accompanied by a Posterior Malleolar Fracture: A Nonfixed Posterior Fracture Fragment May Not Affect Postoperative Tibiofibular Joint Malreduction Rates.

The fact that lateral malleolar fracture is accompanied by posterior malleolar fracture may adversely affect syndesmosis malreduction rates. We aimed to compare syndesmosis malreduction rates determined on postoperative radiographs between isolated lateral malleolar fractures and lateral malleolar fractures accompanied by posterior malleolar fractures. We retrospectively examined 128 operative patients: 73 with isolated lateral malleolar fractures (group L) and 55 with lateral + posterior malleolar fractures (group LP). In group LP, no patients received posterior fragment fixation. In both groups, indirect syndesmosis fixation was performed with a single screw after open reduction and internal fixation of the lateral malleolus. Patient age, sex, fracture side, fracture type (Lauge-Hansen and Danis-Weber classifications), Kellgren-Lawrence osteoarthritis classification, syndesmotic incongruency on postoperative radiographs, syndesmotic malreduction of postoperative fibula fracture, fracture union time, complication rates, accompanying injuries, and preoperative and postoperative radiographic syndesmotic measurements (tibiofibular overlap, tibiofibular clear space, medial clear space) were recorded, and the groups were compared. Mean ± SD age was 44.32 ± 15.66 years in group L and 48.93 ± 14.03 years in group LP (P = .087). There were no significant differences in preoperative and postoperative tibiofibular distance, tibiofibular overlap, and medial clear space values between groups (P > .05). The prevalence of grade 2 fractures according to the Kellgren-Lawrence classification was significantly higher in group LP (P = .047). Postoperative syndesmosis malreduction was detected in 12 patients in group L and in nine in group LP (P = .991). In lateral malleolar fractures accompanied by small-fragment posterolateral or avulsion-type posterior malleolar fractures, closed syndesmotic screw fixation does not cause syndesmosis malreduction.

A rebbachisaurid-mimicking titanosaur and evidence of a Late Cretaceous faunal disturbance event in South-West Gondwana

The evolution of ecosystems during the late Mesozoic on the southern landmasses is complex and still poorly known. Starting from a single vicariant Laurasian–Gondwanan scenario, the paleobiogeographic and biostratigraphic models have become more complex, including vicariant, dispersal, and local extinctions as major drivers of changes in the Cretaceous ecosystems during the isolation and posterior fragmentation of Gondwana. However, the direct effects of replacement and the adaptive evolution of terrestrial vertebrates to fill vacant ecological niches after disruptive ecological events have been poorly discussed. Here, we provide a preliminary description of a nearly complete new titanosaurian sauropod from the Upper Cretaceous of Patagonia, Inawentu oslatus gen. et. sp. nov., that shows remarkable convergent anatomical traits with rebbachisaurid sauropods. A phylogenetic analysis recovers it within a not previously recovered titanosaurian subclade, named Clade A, which would be endemic to the Upper Cretaceous of South America. The convergent evolution between rebbachisaurids and Clade A members is interpreted as the result of the same ecological niche exploitation. The biostratigraphic scenario during the Late Cretaceous of South America leads to interpret rapid speciation of the titanosaurs because of filling the empty ecological niche left by the extinction of the rebbachisaurids, an idea concordant with a regional disturbance event of the ecosystems in this continent between 90 and 85 Ma.

Predicting the Potential Complications of Lateral Column Lengthening: A Cadaveric Biomechanical Study

Category: Hindfoot; Other Introduction/ Purpose: Lateral column lengthening calcaneus osteotomy is a common procedure used to treat flatfoot deformity. However, the incidence of subtalar joint impingement and sinus tarsi pain presents a concern related to this treatment. The hypothesis of this study was with opening of the osteotomy, the anterior fragment of the calcaneus anterior process moves anteriorly, while the posterior fragment simultaneously moves posteriorly which can compromise the outcome as well as cause subtalar joint impingement. The goal of this study was to observe movements of the anterior and posterior fragments with an osteotomy of different sizes. Methods: Eight fresh frozen cadaveric feet were used. A vertical calcaneus osteotomy was designed 1.5cm posterior to the calcaneocuboid joint. Optical markers were attached on each side of the osteotomy to measure movements of the anterior and posterior segments during the lengthening procedure. Three more markers were placed for reference purposes with one on the lateral process of the talus, one on the table, and one on the base of the 3rd metatarsal (Figure 1). Following the osteotomy 4mm, 6mm, 8mm, 10mm and 12mm of lengthening was obtained for each specimen using a lamina spreader. The exact lengthening achieved was measured with a micro-caliper. Movements of the anterior and posterior fragments were recorded using a Sentech model STC-MBCM401U3V camera and calculated with MaxTRAQ motion analysis software. Mixed linear regression analyses were performed using R Studio. Results: With the open osteotomy, the anterior fragment moved anteriorly, while the posterior fragment moved posteriorly (Table 1, 2). The anterior movement was larger than the posterior one. There was no difference in the amount of anterior movements during each attempted 2mm lengthening, however, the amount of the posterior movement peaked at 6mm-8 mm and went down at 8mm-10mm and 10mm-12mm, which was caused by subtalar joint impingement and limited the posterior excursion. Starting at 6mm lengthening there was a linear regression relationship between the anterior &amp; posterior movement and the lengthening (anterior movement = -4.80 + 1.06 × Lengthening of the Lateral Column, posterior Movement = -1.26 + 0.22 × Lengthening of the Lateral Column) (Figure 2,3). 1mm lengthening induced 1.06mm anterior (p &lt; 0.05), and 0.22mm posterior shift (p &lt; 0.05). Conclusion: Lateral lengthening causes the calcaneus to move both anteriorly and posteriorly which not only compromises the power of the procedure, but also can cause subtalar impingement. The findings of this study provide our colleagues with more insight into the correlation between the size of the lengthening, results, and potential complications.

A Prospective Randomized Study Comparing the Outcomes of Fixed vs Non-Fixed Middle-Sized Posterior Malleolus Fractures

Category: Ankle; Trauma Introduction/Purpose: The controversy surrounding the indications for fixation of posterior malleolar fractures remains unresolved, particularly in cases of middle-sized fragments that make up between 10-25% of the joint surface. Although several studies have been conducted, the evidence to support the need for fixation of such fragments is limited, with a lack of level 1 evidence. This study aimed to assess patients with ankle fractures involving middle-sized posterior fragments and compare those who received posterior malleolus fixation to those who did not. The hypothesis was that fixation of middle-sized (10-25%) posterior malleolar fractures would result in superior functional and radiological outcomes in the short to mid-term follow-up. Methods: A prospective randomized-controlled study was conducted to assess the effects of posterior malleolus fixation in patients with acute rotational ankle fractures involving a middle-sized fragment. Eligible patients were included and randomly allocated into two groups, Group 1 receiving open reduction and internal fixation without posterior malleolus fixation, and Group 2 receiving the same procedure with posterior malleolus fixation, following informed consent. Prior to the study, a power analysis was conducted, indicating that a minimum of 16 patients in each group would be necessary to achieve 80% power and a 5% significance level. The randomization was conducted using an even/odd numbers technique, resulting in 20 patients in each group. Patient clinical and functional status was evaluated annually postoperatively, utilizing the VAS pain scale, AOFAS and SMFA scales. Radiological evaluations were conducted through direct radiographs, utilizing articular step-off evaluation and the Kellgren Lawrence osteoarthritis grading system. Results: The groups were comparable in terms of age, BMI, gender, and fracture type distribution. There were no significant differences in average follow-up times, posterior malleolus size, or height values. However, articular step-off greater than 1mm was more common in Group 1 (p=0.04). Despite slightly better functional outcomes in Group 2, there were no significant differences between the two groups in terms of VAS pain, AOFAS, or SMFA scores (functional, bothersome, and total). However, there was a trend towards significance in the SMFA Function score difference (p=0.07). Multivariate analysis showed that Haraguchi type 1 fractures had better functional outcomes in only the SMFA Bothersome parameter (p=0.03). Patients with articular step-off greater than 1 mm had significantly worse outcomes in all SMFA and AOFAS parameters (p &lt; 0.05). Conclusion: In patients with closed rotational ankle fractures involving medium-sized (10-25%) posterior fragments, there was no significant improvement in functional or radiological outcomes with posterior fragment fixation at short to mid-term follow-up. Patients without posterior fixation were more likely to have articular step-off greater than 1 mm, which was associated with poorer functional outcomes. Despite similar outcomes in both groups, posterior fragment fixation may decrease the incidence of articular step-off and contribute to improved functional outcomes.

Regeneration in a Neotropical land planarian (Platyhelminthes, Tricladida)

Planarians are known for their ability to regenerate missing body parts. However, little is known about the regeneration ability of land planarians, especially regarding Neotropical species. Herein, we investigated the regeneration in the Neotropical land planarian Luteostriata abundans. Specimens were cut in two at different points along the body and monitored for 50 days. Larger and anterior pieces survived more than smaller posterior pieces. Anterior pieces that retained the pharynx continued to feed normally as intact animals, while posterior pieces that retained the pharynx lost its function temporarily. The growth rate was similar amongst all pieces across 50 days. Anterior mouthless pieces regenerated the pharynx and mouth significantly faster than posterior mouthless pieces. After 50 days, the relative position of the mouth along the body reached values close to intact animals in all regenerating pieces. In general, anterior pieces showed higher survival and regenerated faster than posterior fragments, which agrees with observations with other planarian species. However, surviving posterior pieces were able to retain the proportions of intact animals as well. Our results suggest that L. abundans has a good regenerative capacity similar to many freshwater planarians.

Arthroscopic-assisted reduction and internal fixation for complex tibial plateau fracture: radiographic and clinical outcomes with 2- to 15-year follow-up

BackgroundTo investigate the radiologic and prognostic outcomes after using arthroscopic-assisted reduction and internal fixation (ARIF) in complex tibial plateau fractures with mid- to long-term follow-up.MethodsThis retrospective study reviewed complex tibial plateau fractures that underwent ARIF from 1999 to 2019. Radiologic outcomes, including tibial plateau angle (TPA), posterior slope angle (PSA), Kellgren–Lawrence classification and Rasmussen radiologic assessment, were measured and evaluated. The prognosis and complications were assessed by the Rasmussen clinical assessment with a minimum follow-up of 2 years.ResultsNinety-two consecutive patients (mean age: 46.9 years) with a mean follow-up of 74.8 months (24–180) were included in our series. Using AO classification, there were 20 type C1 fractures, 21 type C2 fractures, and 51 type C3 fractures. All the fractures achieved solid union. TPA was maintained well on average at the last follow-up and showed no significant difference compared to postoperatively (p = 0.208). In the sagittal plane, the mean PSA increased from 9.3 ± 2.9° to 9.6 ± 3.1° (p = 0.092). A statistically significant increase in PSA was also noted in the C3 group (p = 0.044). Superficial or deep infection was noted in 4 cases (4.3%), and total knee arthroplasty (TKA) was performed in 2 cases (2.2%) due to grade 4 osteoarthritis (OA). Ninety (97.8%) and 89 (96.7%) patients had good or excellent results in the Rasmussen radiologic assessment and Rasmussen clinical assessment, respectively.ConclusionsThe complex tibial plateau fracture could be treated successfully using arthroscopy-assisted reduction and internal fixation. Most patients achieve excellent and good clinical outcomes with low complication rates. In our experience, a higher incidence of increased slope was noted, especially in type C3 fractures. Reduction of the posterior fragment should be done cautiously during the operation.Levels of evidenceLevel III.

Two-staged management of ankle fracture-dislocations with a posterior fragment: computer-tomography-based classification, treatment and its outcome.

Trimalleolar fractures are difficult to treat and malreduction can lead to functional impairment. Involvement of the posterior malleolus has a poor predictive value. Current computed-tomography (CT)-based fracture classifications led to an increase in fixation of the posterior malleolus. The aim of this study was to describe the functional outcome after a two-stage stabilisation with direct fixation of the posterior fragment in trimalleolar dislocation fractures. In a retrospective study, all patients presenting with a trimalleolar dislocation fracture, an available CT scan, and a two-stage operative stabilisation including the posterior malleolus by a posterior approach were included. All fractures were treated with initial external fixator and delayed definitive stabilisation including fixation of the posterior malleolus. Next to clinical and radiological follow-up, outcome measures (Foot and Ankle Outcome Score (FAOS), Numeric Rating Scale (NRS), Activity of Daily Living (ADL), Hulsmans implant removal score) and complications were analysed. Between 2008 and 2019, of 320 trimalleolar dislocation fractures, 39 patients were included. Mean follow-up was 49months (standard deviation (SD) 29.7, range 16-148). Mean age was 60years (SD 15.3, 17-84) with 69% female patients. The mean FAOS was 93/100 (SD 9.7, 57-100), NRS 2 (interquartile range (IQR) 0-3) and ADL 2 (IQR 1-2). Four patients showed a postoperative infection, three re-operations had to be performed and implants were removed in 24 individuals. A two-stage procedure of trimalleolar dislocation fractures with in-direct reduction and fixation of the posterior tibial fragment through a posterior approach leads to good functional outcome scores with a low rate of complications.

Lateral tibial plateau fractures with posterior comminution. Can a rim plate offer sufficient support?

Tibial plateau fractures with posterior comminution are difficult to reduce and stabilise. Standard lateral approach doesn't offer adequate visualisation. Posterior approach is suitable for isolated posterior fractures. The addition of a specifically contoured rim plate can enable fixation of posterior fragments through a modified lateral approach.The purpose of this study was to evaluate the advantages and limitations of this novel technique. We present a prospective series of 16 tibial plateau fractures with posterolateral depression, operated over a period of 7 years (04.2014-09.2021). The mean age of the patients was 52 years .They were followed for an average period of one year.Clinical and functional assessment was performed according to the criteria of Knee Society Clinical Rating Score. The lateral and posterior component of the fracture was stabilised by a horizontal rim plate, through a posterolateral approach, with or without fibular osteotomy. 9 patients had excellent, 5 had good, 2 had average ratings. The average objective rating was 87,5 (70- 97), and the average functional rating was - 74,4 (40-100). The average ROM was 110° (100°-120°). Two of the fractures healed in 5° varus and 8° valgus respectively. One knee joint ended up with 10° flexion deficit. Three knees had medio- lateral instability, with no functional impairment. In 4 cases the K wires of the weber fibular osteotomy fixation migrated. The absence of late articular collapse of the treated fractures may be attributed to the initial stability of fixation.The addition of a rim plate addresses the posterior comminution and makes early rehabilitation safe.

The Influence of Sagittal Angle of Posterior Malleolus Fracture on Ankle Joint Stability: A Retrospective Study of 120 Cases.

Due to the different force exerted during the posterior malleolus fracture (PMF), the difference in sagittal angle (SA) between the fracture fragments may affect ankle stability. But this aspect is less well studied and the aim of this study was to investigate the relationship between SA and the stability of PMF. The imaging data of 120 patients with PMFs from January 2014 to November 2022 were collected retrospectively and reconstructed. We first measured SA, posterior fragment area (PFA) and fragment area ratio (FAR), reanalyzing the correlation of SA with PFA and FAR, respectively. To better describe the morphological characteristics of the fracture fragments, we further measured the fragment width diameter ratio (FWR), the fragment length ratio (FLR), fragment height (FH), contact area (CA), and finally carried these data into the regression model of SA versus FAR to conduct the intermediary role. SA was negatively correlated with PFA(s) (r = -0.583, P < 0.001), with regression equation s = -0.063SA + 3.066; SA was negatively correlated with FAR (r = -0.204, P < 0.05), with regression equation FAR = -0.002SA + 0.198; A significant correlation was found between FWR, FLR, FH, CA and SA (P < 0.05), as well as between FWR, FLR, FH and FAR (P < 0.05); Further intermediary role analysis showed that FWR, FLR, FH had a partial intermediary role between SA and FAR. As SA increased, PFA and FAR decreased, so the larger the SA was due to the effect of vertical shear force, reflecting higher ankle stability, meanwhile, FWR, FLR and FH should also be considered on the fixation method of fracture fragments.

Pathoanatomy of pertrochanteric fractures - a postmortem study

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

Middle-sized posterior malleolus fractures: Fixed versus non-fixed – A prospective randomized study

PurposeThis study aimed to assess the impact of fixation on functional and radiological outcomes of ankle fractures involving the posterior malleolus. We hypothesized that fixation of the posterior malleolus would be associated with improved radiological and functional outcome. MethodsA prospective randomized controlled study was planned and 40 consecutive ankle fractures involving middle-sized (10–25%) posterior fragment were included. Posterior fragments in Group 1 were not fixated while Group 2 underwent posterior malleolus fixation. The patients were evaluated both functionally and radiologically at minimum 2-years. ResultsDemographics and fracture type distributions were similar between the groups. Despite the slightly better functional outcome in Group 2, no significant functional or radiological outcome difference could be detected. Articular step-off> 1 mm was more common in Group 1 (p = 0.04) and the patients with articular step-off showed significantly worse functional outcome in all functional parameters (p < 0.05). Radiological and functional outcome parameters were positively correlated when all patients were evaluated together. Lateral radiographs caused an overestimation in the size of posterior fragment compared to CT (p < 0.001). ConclusionAlthough there was a slightly better clinical outcome in patients with fixed posterior fragments, it was not significant at short to mid-term follow-up. However, posterior fragment fixation contributed to functional outcomes by decreasing the incidence of articular step-off> 1 mm, which was found to be a negative prognostic factor. Level of evidenceLevel I; prospective randomized controlled study.

Reduction Quality in Posterior Malleolar Fractures using the Modified Posteromedial Ankle Approach

Category: Trauma; Ankle Introduction/Purpose: Several studies have documented which of the posterior ankle approaches has the best exposure of the posterior malleolus. However, no study has made a correlation between the quality of posterior fragment reduction using CT scan and the approach used. The purpose of this study was to assess the quality of reduction of posterior malleolus fractures in patients with trimalleolar ankle fractures operated with the modified posteromedial approach. Methods: A retrospective search was performed in two Health Centers between 2014 and 2021 for patients with ankle fracture dislocations associated with types two, three and four PM fractures according to the Bartonicek classification3. In relation with the inclusion criteria, patients included in the study had complete trauma ankle set radiographs and CT scans with axial, sagittal and coronal planes pre and postoperative and in all of them a direct reduction and internal fixation of the posterior malleolus was achieved with the modified posteromedial approach. All procedures were performed by six experienced Foot and Ankle Surgeons. 48 patients met the inclusion criteria (29 women and 19 men) with a mean age of 46 years (range 23-80). 6 patients required two stage management with an initial external fixation because of irreducible fracture-dislocations or soft tissue compromise and in a second time the final ORIF. Results: Axial CT Plane Evaluation Evaluation of the morphology of the fractured PM according to the Bartonicek classification on the CT scan axial planes showed type II in 11 patients, type III in 31 patients and type IV in 7 patients. In relation to fibular position at the fibular notch 39 patients showed adequate reduction. Four patients showed diastasis or GAP &gt;= 2mm as a consequence of intercalary fragment unreduced. Sagittal CT Plane Evaluation Sagittal CT plane evaluation showed anatomical reduction (&lt;2mm) in 45 patients and poor reduction in 3 patients. Fourteen patients showed residual impaction either in posteromedial (type III fractures) or posterolateral fragments (type II, III or IV fractures). Conclusion: In conclusion, we think the modified posteromedial approach is a good option to manage trimalleolar fractures, since we achieved an anatomic posterior malleolus fracture reduction in 94% of our patients.

A preliminary study of the surgical approach for posterior tibial plateau fractures: Based on posterior fragment segment classification

PurposeThe optimal surgical approach for the posterior tibial plateau fractures (PTPFs) remains controversial. This study aims to establish a method for posterior fragment segment classification to guide the choice of surgical approach and to reveal the outcome of their early reduction and health status. MethodsThe medical records of 42 PTPFs patients treated with the strategy were collected retrospectively from December 2017 to December 2021. The posterior cortex of the tibial plateau was classified into postero-medial (PM), postero-central (PC), and postero-lateral (PL) segments. A posteromedial inverted L-shaped approach was adopted when the fractures involved the PM segment in the presence or absence of PC. The Frosch approach was performed when the PL segment was concerned. Fractures containing both PM and PL segments were treated by combined approaches. Four factors were measured to evaluate the reduction effect, including medial proximal tibial angle (MPTA), lateral posterior slope angle (LPSA), medial posterior slope angle (MPSA), and articular step-off. The Short Form 36 (SF-36) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were completed at the last follow-up to assess health status and the degree of osteoarthritis. ResultsA posteromedial inverted L-shaped approach was adopted in 16 PTPFs patients, a Frosch approach was adopted in 14 PTPFs patients, and a combined approach was adopted in 12 PTPFs patients. Immediate radiographic results indicated a promising fixation performance with this treatment strategy. The results of SF-36 and WOMAC scores reported good health status in all patients with a mean follow-up time of 34.50 (23–50) months. Two patients developed superficial wound infections, and one patient had liquefaction necrosis in adipose tissue. Although skin numbness occurred in 4 patients, they recovered within 6 months. ConclusionPTPFs patients treated under the guidance of posterior fragment segment classification achieved encouraging levels of immediate fixation and health status.

Does the posterior approach offer advantages in short-term in trimalleolar ankle fractures?

Objective: The aim of this study was to compare the early (nine months after surgery) synthesis of the posterior malleolus by direct posterior (P) approach versus the percutaneous anteroposterior (AP) screw in trimalleolar ankle fractures to analyze the early clinical status of the patient (eight months) by studying the American Orthopedic Foot And Ankle Society (AOFAS) scale to compare postsurgical clinical recovery between both approaches, the rate of hospital days in both groups, the quality of joint reduction by computed tomography (CT) study and the rate of most frequent complications (fibular tendinopathy and surgical wound). Methods: A retrospective comparative study was performed between 2016-2020, including 94 patients with trimalleolar ankle fracture type 44-A/B/C (27 percutaneous AP surgical treatment and 67 P approach). Both groups were compared by analyzing demographic variables, clinical-functional status, radiological variables, and complications. Statistical analysis was performed using SPSS-20, with a p-value of 0.05 as significance. Results: Demographically, both groups were comparable, not finding significant differences between them. An increase in the days of admission before surgery was observed in the P approach with a mean of 4 (p=0.001). No significant clinical differences were found in the AOFAS scale, with a mean of 85 in both groups. Regarding the radiological result, a better reduction was observed with P approach (good=57, fair=9, poor=0) compared to the AP approach (good=10, fair=7, poor=9) (p=0.001). As for the complications, no significant differences were observed for the surgical wound. However, a higher need for fibular plate removal could be observed with P approach (n=17) (p=0.046). Conclusions: Clinically, both groups observed no significant differences through the AOFAS scale. The posterolateral approach has a higher rate of hospital days before surgery. Radiologically, a better joint reduction is achieved by a direct approach to the posterior fragment. Level of Evidence III; Retrospective Comparative Study.

Variation in posterior fragment fixation in the Netherlands: a nationwide study.

The treatment of the posterior fragment in trimalleolar fractures differs from hospital to hospital in the Netherlands. A nationwide survey was performed to evaluate the fixation criteria and practice variation. An online cross-sectional survey amongst (orthopaedic) trauma surgeons was performed in the Netherlands. It consisted of three sections: a general section, a section showing preoperative images of six cases and a section with postoperative images of nine cases. A total of 151 surgeons completed the online survey. 45% of the respondents indicated that they fixated the posterior fragment if smaller than 25% of the intra-articular surface. 48% preferred an open posterior approach to fixate the posterior fragment. There was good consensus in treatment for the two cases with Bartonicek type 4 fractures (operative treatment in 73 and 72% respectively). Little consensus was found for Bartonicek type 2 and 3 fractures (88% opted for operative treatment in one case, but 89% for conservative treatment in the second case). Reoperation was mostly considered in cases with a step-off of more than 1mm (by 33-38% of the respondents). There was great variation in the choice of treatment if only the size of the posterior fragment was considered. Other fixation criteria such as postoperative step-off or instability after fixation of the lateral and medial malleoli are taken into account. In cases where fixation was needed, a percutaneous approach and an open posterolateral approach were equally preferred. There is much variation in treatment of the posterior malleolar fracture amongst orthopaedic and trauma surgeons in the Netherlands. The percutaneous approach and open posterolateral approach to fixate the posterior malleolar fracture seem to be equally used in the Netherlands. Still, there is no uniformity in treatment of posterior malleolar fracture, especially for Bartonicek 2 and Bartonicek 3 fractures. Reoperation is considered by less than half of the surgeons in case of postoperative persistent step-off of more than 1mm.

A new specimen of pteranodontid pterosaur Bogolubovia orientalis from the upper cretaceous of Penza Province, Russia

ABSTRACT Bogolubovia orientalis, the first pterosaur taxon described from Russia, was known for more than a hundred years from a single specimen, the posterior fragment of the middle cervical vertebra from the Upper Cretaceous (upper Campanian) Rybushka Formation at Malaya Serdoba locality in Penza oblast, Russia. First classified as a pteranodontid, Bogolubovia was long thought to be an azhdarchid, and only very recently has it been again reclassified as a pteranodontid. Here, we describe the second pterosaur vertebra from the Malaya Serdoba locality, an atlantoaxis, which shows distinct pteranodontid characters, such as round cotyle, lack of hypapophysis, rudimentary diapophysis placed anterior to the lateral pneumatic foramen, and pair of posterior lateral pneumatic foramina. The pteranodontid characters of the holotype middle cervical vertebra include high neural arch, which is higher than the centrum and has the postzygapophyses placed well above the condyle, and the large posterior lateral foramina, similar in size with the posterior opening of the neural canal. Both vertebrae can be assigned to the same taxon, Bogolubovia orientalis. Bogolubovia can be distinguished from the pteranodontids Pteranodon and Volgadraco and thus is considered a valid taxon.

New species and records of Caulleriella, Chaetocirratulus and Chaetozone (Annelida, Cirratulidae) from continental shelf and slope depths of the Western North Atlantic Ocean

Seventeen species of cirratulid polychaetes, 13 new to science, are reported from continental shelf and slope depths of the western North Atlantic Ocean. The samples were collected as part of deep-water offshore reconnaissance surveys from New England to the Carolinas and long-term monitoring programs in Boston Harbor, Massachusetts Bay, and Georges Bank off Massachusetts. The new species are included in the genera Caulleriella (C. cryptica n. sp.), Chaetocirratulus (C. hessleri n. sp., C. sandersi n. sp., and C. tomaculus n. sp.), and Chaetozone (C. adunca n. sp., C. artaspinosa n. sp., C. brychiata n. sp., C. castouria n. sp., C. donerae n. sp., C. lophia n. sp., C. novagracilis, n. sp., C. paucispinosa n. sp. and C. profunda n. sp. In addition, Chaetozone gayheadia Hartman, 1965 is redescribed based on type-material and additional collections and transferred to the genus Chaetocirratulus. Chaetozone benthaliana McIntosh, 1985 is designated a species inquirendum because it was described from a posterior fragment that cannot be confirmed as belonging to any known cirratulid genus or species. Updated descriptions and new records are provided for Chaetozone anasima, C. diodonta, and C. hystricosa all originally described by Doner Blake (2006).