Gluteal Complex is important in External Snapping Hip: intraoperative identification of syndrome origin and endoscopic stepwise release-a case series.

PURPOSE: External snapping hip syndrome (ESHS) was historically attributed to isolated iliotibial band (ITB) contracture. However, the gluteus maximus complex (GMC) may also be involved. This study aimed to intraoperatively identify the ESHS origin and assess the outcomes of endoscopic treatment based on the identified aetiological type. METHODS: From 2008-2014, 30 consecutive patients (34 hips) with symptomatic ESHS cases refractory to conservative treatment underwent endoscopic stepwise "fan-like" release, gradually addressing all known reasons of ESHS: from the isolated ITB, through the fascial part of the GMC until a partial release of gluteus maximus femoral attachment occurred. Snapping was assessed intra-operatively after each surgical step and prospectively recorded. Functional outcomes were assessed via the MAHORN Hip Outcome Tool (MHOT-14). RESULTS: Twenty seven patients (31 hips) were available to follow-up at 24-56 months. In all cases, complete snapping resolution was achieved intra-operatively: in seven cases (22.6%) after isolated ITB release, in 22 cases (70.9%), after release of ITB + fascial part of the GMC, and in two cases (6.5%) after ITB + fascial GMC release + partial release of GM femoral insertion. At follow-up, there were no snapping recurrences and MHOT-14 score significantly increased from a pre-operative average of 46 to 93(p<0.001). CONCLUSION: Intraoperative identification and gradual addressing of all known causes of ESHS allows for maximum preservation of surrounding tissue during surgery while precisely targeting the directly involved structures. Endoscopic stepwise "fan-like" release of the ITB and GMC is an effective, tailor-made treatment option for ESHS regardless of the snapping origin in the patients with possibility to manually reproduce the snapping.

Symmetry-driven diastereoselective functionalization of simple trianglamine.

We have found that derivatization of the trianglamine macrocycle by aliphatic aldehydes leads selectively to one of the two possible diastereomeric aminal products. X-ray analysis, NMR measurements and DFT calculations pointed to the product possessing a higher symmetry.

Both arthroscopic and open posterior knee capsulotomy are effective in terms of extension recovery and functional improvement-systematic review.

PURPOSE: To assess the recovery of extension and improvement in functional scores after an arthroscopic or open posterior knee capsulotomy in the setting of an extension deficit. METHODS: A systematic search of articles published between 1980 and 2020 was performed in the MEDLINE/PubMed database, EMBASE/Ovid database and Web of Science database. The inclusion criteria consisted of patients with primary extension deficits > 5° who underwent an arthroscopic or open posterior knee capsulotomy. The assessed outcomes were preoperative and postoperative range of motion and functional outcome scores. Randomized controlled trials, cohort studies and case series with a follow-up longer than 6 months were included. The risk of bias was assessed using the Joanna Briggs Institute critical appraisal tool for case series. The certainty of evidence was assessed using the GRADE approach. RESULTS: Of 226 records identified through database searching, 7 studies were included in the final analysis. The outcomes of 107 patients with a mean age of 34.1 (range 15-63) years were available. In all the included studies, a posterior capsulotomy resulted in the restoration of knee extension to normal or nearly normal values (mean postoperative extension deficit: 0.4-4.2 degrees) with a significant increase in functional outcome scores. No neurovascular complications were reported within the studies. Due to the diverse methodology of studies, the direct comparison of arthroscopic versus open approaches was not possible. Concerning the risk of bias assessment, the greatest concerns raised the selection of participants among the included studies and the methods of outcome measurement. The certainty of evidence was very low according to the GRADE. CONCLUSIONS: Both arthroscopic and open posterior capsulotomy of the knee results in restoration of normal or nearly normal knee extension and significant improvement in functional outcomes. LEVEL OF EVIDENCE: IV.

Intra- and postoperative assessment of femoral component rotation in total knee arthroplasty: an EKA knee expert group clinical review.

PURPOSE: Malrotation of the femoral component after primary total knee arthroplasty (TKA) is one of the most important problems leading to painful TKA requiring revision surgery. METHODS: A comprehensive systematic review of the literature was performed to present current evidence on how to optimally place the femoral component in TKA. Several landmarks and techniques for intraoperative determination of femoral component placement and examination of their reliability were analyzed. RESULTS: 2806 articles were identified and 21 met the inclusion criteria. As there is no unquestioned gold standard, numerous approaches are possible which come along with specific advantages and disadvantages. In addition, imaging modalities and measurements regarding postoperative femoral component rotation were also investigated. Femoral component rotation measurements on three-dimensional (3D) reconstructed computerised tomography (CT) images displayed intraclass correlation coefficients (ICC) above 0.85, significantly better than those performed in radiographics or two-dimensional (2D) CT images. Thus, 3D CT images to accurately evaluate the femoral prosthetic component rotation are recommended, especially in unsatisfied patients after TKA. CONCLUSION: The EKA Femoral Rotation Focus Group has not identified a single best reference method to determine femoral component rotation, but surgeons mostly prefer the measured resection technique using at least two landmarks for cross-checking the rotation. LEVEL OF EVIDENCE: III.

One-Step Construction of the Shape Persistent, Chiral But Symmetrical Polyimine Macrocycles.

A unique combination of structural flexibility, shape persistency and functionality, makes macrocycles and molecular cages as essential molecular entities that have displayed applications that go beyond chemistry. Among macrocycles, the selectively obtained symmetrical (poly)cyclic polyimines have shown great utility in the design of molecules varied in shape and properties. The reversible and thermodynamically controlled cycloimination reaction is governed by configurational and conformational constraints imposed on the intermediate products, ensures a sufficiently high level of preorganization. The high geometrical control over the macrocycle structure has profound effect on their assembly mode. In this Account, we were interested in showing how the structure of small building blocks affects the structure of macrocyclic product and further, how influenced the association mode of the given macromolecule. The latter is of primarily importance in supramolecular and in material chemistry.

Retraction Note: An evaluation of the potential consequences of drilling titanium and tantalum implants during surgery - a pilot study.

The authors have retracted this article [1] because it constitutes redundant publication [2].

Chiral dialkyl ditellurides: Conformation of chiral chromophore by circular dichroism and DFT calculation.

The twisted structure of ditellurides, in a similar way as in other dichalcogenes, leads to different absorption of circularly polarized light by quasi-enantiomeric chiral orbitals. Chiral optically active ditellurides are not common compounds and this phenomenon is not widely reported. As chiral ditellurides found an application in asymmetric synthesis, their molecular structure, understood as their conformation, became an important factor for understanding their reactivity. Until now there are few examples of chiral ditellurides known and their structure was not analyzed in details. This article presents the results of our most recent research on the structure of chiral ditellurides investigated by electronic circular spectroscopy (ECD) supported by quantum-chemical calculation. This enables us to suggest a relationship between chirality of alkyl substituent and chirality (conformation) of ditelluride.

An evaluation of the potential consequences of drilling titanium and tantalum implants during surgery - a pilot study.

BACKGROUND: The aim of the study was to evaluate the potential consequences of drilling titanium alloy (Ti) and tantalum (Ta) implants. METHODS: During an in vitro study, four holes were made in each of two spatially porous trabecular implants: one Ta and the other Ti alloy (Ti-6Al-7Nb). The weight and the volume of particles produced during the drilling were then measured using a Radwag XA 110/2X (USA) laboratory balance. RESULTS: The loss of mass of the Ti and Ta implants was respectively 1.26 g and 2.48 g, and the volume of free particles was respectively 280 mm3 and 149 mm3. The particles were recovered after each stage. Despite the use of 5 µm filters, around 0.6% of the total implant mass from both implants was not recovered after drilling (roughly 2% of the mass of the particles created). CONCLUSION: It is technically difficult to make holes in Ti and Ta implants using standard surgical tools, and the process creates a significant amount of metal particles which cannot be removed, despite intensive flushing. This may have a potentially adverse influence on the survival of the implant and result in negative systemic consequences.

Quantitative cotyloid fossa thickness and proximity to obturator neurovascular bundle: implications for arthroscopic ligamentum teres reconstruction.

The aim of the present study was to report the in vivo thickness of the cotyloid fossa at the acetabular ligamentum teres (LT) attachment and investigate the clearance of the obturator neurovascular bundle. Fifty-five consecutive patients undergoing a total hip arthroplasty for hip osteoarthritis were included. The thickness of the cotyloid fossa was measured at the acetabular LT attachment using a standard depth gauge. The minimal distance (clearance) of the obturator neurovascular bundle to the center of the acetabular LT attachment was measured in 7 patients (14 hips) who also underwent a computed tomography angiography. The average thickness of the cotyloid fossa at the acetabular LT attachment was 4.1 ± 2.3 (range: 1-10) mm. The obturator vein was closest to the acetabular LT attachment, but the clearance was more than the defined safe zone of 15 mm in all cases. Based on the current findings, it can be assumed that bone anchors might not be suitable for fixation of the graft in LT reconstruction (LTR) and an alternative implant such as a cortical button should be considered. Acetabular fixation of the graft with a 12-mm cortical button is relatively safe concerning injury to obturator neurovascular structures. The results of the present study provide a better understanding of the cotyloid fossa anatomy and might be relevant for surgeons who perform arthroscopic LTR.

Vibrationally resolved circular dichroism spectra of a molecule with isotopically engendered chirality.

We present a theoretical study of vibrationally resolved circular dichroism spectra, both in the adiabatic and non-adiabatic frameworks, with a full account of Franck-Condon and Herzberg-Teller vibrational contributions for the former. Model calculations have been performed on 2(R)-deuteriocyclopentanone, whose chirality is due solely to isotopic substitution. This molecule has two distinct, nearly isoenergetic, half-chair conformations in equilibrium, and its demanding nature in terms of computational accuracy makes it a perfect candidate for performing a detailed comparison between different vibronic models. Comparisons are made with experimental spectra, and we also consider temperature effects. In order to reproduce the experimental spectrum, it is necessary to consider the geometry relaxation occurring during the n→π* transition.

Transient spontaneous osteonecrosis of the knee (SONK) shortly after SARS-CoV-2 infection: A report of 2 cases.

BACKGROUND: This article describes 2 cases of post-coronavirus disease 2019 (COVID-19) transient spontaneous osteonecrosis of the knee (PCT-SONK) observed in patients who had previously recovered from COVID-19 without corticosteroid administration. OBJECTIVES: The possible pathomechanisms by which a recent SARS-CoV-2 infection may contribute as a causative factor for osteonecrosis are reviewed, and the differential diagnosis and treatment are discussed. MATERIAL AND METHODS: Two patients (males, 45- and 47-year-old) presented with sudden onset knee pain with no trauma history. The pain persisted during rest and at night. On magnetic resonance imaging (MRI), no subchondral bone thickening was observed; bone edema was diffusely distributed in the whole femoral condyle, in contrast to the more focal edema that is typically concentrated mainly around the subchondral region in classic SONK. Both patients were treated nonoperatively with no weight bearing and pharmacological agents, and complete resolution of symptoms was achieved. RESULTS: A follow-up MRI 10 weeks after presentation revealed a near-complete loss of signal in the medial femoral condyle in both patients. CONCLUSION: Orthopedic surgeons should be cautious when sudden knee pain without concurrent trauma or a history of injury occurs shortly after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, even with mild COVID-19 illness. While some studies report the development of post-COVID-19 osteonecrosis after lower doses of corticosteroids and sooner after their administration than in comparable non-COVID-19 cases, our study is the first to report 2 cases with no corticosteroid administration at all. Therefore, the authors believe it adds to the body of knowledge on the potential connections between COVID-19 and PCT-SONK. The transient nature of symptoms and radiological findings suggest that aggressive surgical treatment of non-injury local bone edema occurring shortly after SARS-CoV-2 infection should be avoided.

Ligamentum teres reconstruction with labrum and capsule repair after posterior acetabular wall fracture: a case report.

The aim of this case study is to present arthroscopic treatment of recurrent hip instability after acute post-traumatic posterior hip dislocation with a fracture of the posterior acetabular wall. A male patient aged 35 suffered a dislocation of the right hip joint with a fracture of the posterior acetabular wall due to an accident. The fracture was stabilized during emergency surgery with a locking compression plate, and the patient was released home in a hip brace. Multiple dislocations of the hip joint followed with the implant being confirmed as stable. Decision was made to qualify the patient for a right hip arthroscopy. During the surgery, ligamentum teres was reconstructed using gracilis and semitendinous muscle grafts, followed by the labrum and joint capsule repair, where the surgery that stabilized the acetabular wall fracture had damaged them. There were no complications following the procedure. Short-term follow-up of 3 months demonstrates the patient has a stable hip, reduced pain and has returned to pre-injury activities.

Time efficiency of direct anterior hip arthroplasty compared to postero-lateral approach in elderly patients.

INTRODUCTION: Primary arthroplasty of the hip joint is currently one of the most commonly performed procedures in orthopedics. In Poland we are observing significant changes in the age structure. With the prolonged life more and more elderly patients require musculoskeletal surgery to maintain comfortable and painless mobility. Reducing the duration of the procedure reduces the costs of anesthesiology, surgical and instrument teams, as well as the operating room technical team. The aim of the study was to compare the time required to perform hip joint arthroplasty by the direct anterior approach (DAA) with the postero-lateral approach (PLA) in our hospital. MATERIAL AND METHODS: A retrospective analysis of 559 total and bipolar cemented and cementless hip replacement procedures based on two operative approaches - the minimally invasive DAA over the course of 2 years, and the standard PLA over the course of 3 years - was performed. RESULTS: Statistically significant differences were observed between the approaches used for cementless total arthroplasty with regard to the mean treatment times: 51.9 min for the 272 DAA cases, and 78.3 min for the 190 PLA cases (p < 0.0001). For the cementless hemi-arthroplasty procedure, the mean treatment times were 46.9 min in 36 patients for DAA, and 48.2 min for 61 patients for PLA (p = 0.57). CONCLUSIONS: Minimally invasive DAA significantly shortens the time of the procedure in elderly patients compared to PLA. Further study is needed to analyze other aspects of those two approaches.

The model structure of the hammerhead ribozyme formed by RNAs of reciprocal chirality.

RNA-based tools are frequently used to modulate gene expression in living cells. However, the stability and effectiveness of such RNA-based tools is limited by cellular nuclease activity. One way to increase RNA's resistance to nucleases is to replace its D-ribose backbone with L-ribose isomers. This modification changes chirality of an entire RNA molecule to L-form giving it more chance of survival when introduced into cells. Recently, we have described the activity of left-handed hammerhead ribozyme (L-Rz, L-HH) that can specifically hydrolyse RNA with the opposite chirality at a predetermined location. To understand the structural background of the RNA specific cleavage in a heterochiral complex, we used circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy as well as performed molecular modelling and dynamics simulations of homo- and heterochiral RNA complexes. The active ribozyme-target heterochiral complex showed a mixed chirality as well as low field imino proton NMR signals. We modelled the 3D structures of the oligoribonucleotides with their ribozyme counterparts of reciprocal chirality. L- or D-ribozyme formed a stable, homochiral helix 2, and two short double heterochiral helixes 1 and 3 of D- or L-RNA strand thorough irregular Watson-Crick base pairs. The formation of the heterochiral complexes is supported by the result of simulation molecular dynamics. These new observations suggest that L-catalytic nucleic acids can be used as tools in translational biology and diagnostics.

Thiourea and isothiocyanate--two useful chromophores for stereochemical studies. A comparison of experiment and computation.

Thioureas and isothiocyanates, compounds of high importance in organic synthesis, have not been considered so far as chiroptical probes that can provide structural information from the analysis of circular dichroism spectra. CD spectra of a set of molecules containing the thiourea, isothiocyanate and phthalimide chromophores were obtained and analyzed on the grounds of the calculated populations of conformers and their individual contributions to the CD spectra. It is shown that the thiourea and isothiocyanate chromophores can provide useful structural information from the analysis of their exciton-coupled CD spectra. Exciton-coupled CD spectra of thioureas were found to be sensitive to the Z/E conformation of the chromophore. DFT calculations based on the B2LYP functional were shown to provide a better match with the experimental spectra collected in the short wavelength region, compared to the traditionally used B3LYP functional.

Probing the shapes of chiral bis-(o-naphthalimidobenzoyl) systems using X-ray and circular dichroism methods.

CD (circular dichroism) and X-ray investigations have been carried out in order to identify the prevalent conformations and define the forces that determine the molecular and supramolecular organization of the alkyl-bridged bichromophoric [NAB, ortho-(1,8-naphthalimido)benzoyl] units, each consisting of the benzoyl substituted in the ortho position with the 1,8-naphthalimide group. The results reveal that NAB bichromophores incorporated into the same molecule exist in a variety of conformation/helicity combinations. The molecular structures are largely stabilized by local 1,3-CH/CO dipole-dipole interactions, while the crystal packing besides dispersive H...H interactions is mostly governed by multiple C-H...O(=C) and C-H...pi interactions. The relatively small contribution of pi...pi interactions comes from a pairwise off-face stacking between naphthalimide rings or from pairwise carbonyl...pi interactions. All these types of intermolecular interactions have been summarized quantitatively by means of a Hirshfeld surface analysis.

Treatment of Massive Giant Cell Tumor of Bone of the Proximal Radius. Case Study.

This paper presents a case of a massive giant cell tumor of bone (GCTB), Campanacci and Enneking type III, in an atypical location at the proximal end of the radius. In type I and II cases, surgical treatment is the treat-ment of choice: curettage of the lesion, replacement of bone defects with bone grafts or cement. Advanced type III changes frequently require segmental resection and joint reconstruction. In our patient, a segmental resection of the proximal third of the radius and infiltrated surrounding soft tissues was performed without reconstruction of the radius. A good clinical outcome without a relapse has been noted at one year post surgery.

The Giant Geriatric Syndromes Are Intensified by Diabetic Complications.

By 2015, diabetes has affected more than 415 million people over the world. It is anticipated that 640 million adults will suffer from diabetes in 2040. The elongation of the life expectancy, as the result of better general health care, extends also the time when diabetic complications may develop together with other senility-specific problems. The Giant Geriatric Syndromes (Geriatric Giants) have been qualified by the original Nascher's criteria defined more than 100 years ago, but they are becoming more and more relevant in connection with the aging of societies. The criteria comprise the older age, commonness of the health problem, multifactorial etiology, functional or cognitive impairment, worsened outcome, and increased morbidity and mortality. We described the impact of diabetes on Geriatric Giants including cognitive dysfunction, depression, malnutrition, incontinence, falls and fractures, chronic pain, and the loss of senses. The association of diabetes with Geriatric Giants reveals as a vicious circle with the background of neurovascular complications. However, diabetes influence on the incidence of cancer in elderly was also discussed, since neoplastic diseases associate with Geriatric Giants, for example, chronic pain and depression. The knowledge about these aspects of functional decline in geriatric population is crucial to improve patient care.

Sterically Crowded Trianglimines-Synthesis, Structure, Solid-State Self-Assembly, and Unexpected Chiroptical Properties.

The chiral, triangular-shape hexaimine macrocycles (trianglimines), bearing bulky alkynyl or aryl substituents were synthesized and studied by means of experimental and theoretical methods. The macrocyclization reactions are driven by the extraordinary stability of the trianglimine ring and provided products with high yields. Electrostatic repulsion between imine nitrogen atoms and the substituents forced an anti conformation of the aromatic linkers. Although the DFT-optimized structure of 7 is D3 symmetrical, in the crystal, the macrocycle adopts a bowl-like molecular shape. The macrocycle self-assembles into tail-to-tail dimers by mutual interdigitation of aromatic moieties. In contrast, macrocycle 8 adopts a rigid pillararene-like conformation. The nature of the substituent significantly affects the electronic properties of the linker. As a result, unexpectedly high exciton Cotton effects are observed in the electronic circular dichroism (ECD) spectra. The origin of these effects was subject of an in-depth study.