High tibial osteotomy combined with cartilage restoration: A systematic review of clinical outcomes and prognostic factors.

Background: Focal chondral defects are often treated with cartilage restoration procedures. Malalignment often accompanies chondral defects. High tibial osteotomy (HTO), classically utilized to treat uni-compartmental knee osteoarthritis, corrects malalignment. HTO combined with cartilage restoration procedures can treat uni-compartmental osteoarthritis and focal chondral defects. Purpose: To assess outcomes of combined HTO and cartilage restoration procedures and review prognostic factors that may assist in preoperative planning and patient counseling. Study design: Systematic Review of published literature. Methods: A systematic review of PubMed and Scopus was performed following PRISMA guidelines. Thirty-four papers were included in qualitative considerations. Results: Thirty-four papers that reported the combined outcome of HTO and cartilage repair were included. Twenty of the 34 included papers reported prognostic factors that affected the success or failure of combined HTO and cartilage repair surgery for focal articular defect and uni-compartmental knee osteoarthritis. Cartilage repair techniques that were combined with HTO and included in this review are bone marrow stimulation, allograft transplantation, osteochondral autograft transplantation, autologous chondrocyte implantation, and mesenchymal stem cell implantation. Conclusions: HTO with adjunctive cartilage repair procedures improve clinical outcome scores and restore alignment in patients with medial compartment osteoarthritis and isolated focal chondral defects. HTO with adjunctive cartilage procedures produces optimal results in younger, non-obese patients with focal chondral defects and varus malalignment, without significant lateral compartment and patellofemoral involvement.

Analysis and Modeling of Early Estradiol-induced GREB1 Single Allele Gene Transcription at the Population Level.

Single molecule fluorescence in situ hybridization (smFISH) can be used to visualize transcriptional activation at the single allele level. We and others have applied this approach to better understand the mechanisms of activation by steroid nuclear receptors. However, there is limited understanding of the interconnection between the activation of target gene alleles inside the same nucleus and within large cell populations. Using the GREB1 gene as an early estrogen receptor (ER) response target, we applied smFISH to track E2-activated GREB1 allelic transcription over early time points to evaluate potential dependencies between alleles within the same nucleus. We compared two types of experiments where we altered the initial status of GREB1 basal transcription by treating cells with and without the elongation inhibitor flavopiridol (FV). E2 stimulation changed the frequencies of active GREB1 alleles in the cell population independently of FV pre-treatment. In FV treated cells, the response time to hormone was delayed, albeit still reaching at 90 minutes the same levels as in cells not treated by FV. We show that the joint frequencies of GREB1 activated alleles observed at the cell population level imply significant dependency between pairs of alleles within the same nucleus. We identify probabilistic models of joint alleles activations by applying a principle of maximum entropy. For pairs of alleles, we have then quantified statistical dependency by computing their mutual information. We have then introduced a stochastic model compatible with allelic statistical dependencies, and we have fitted this model to our data by intensive simulations. This provided estimates of the average lifetime for degradation of GREB1 introns and of the mean time between two successive transcription rounds. Our approach informs on how to extract information on single allele regulation by ER from within a large population of cells, and should be applicable to many other genes. AUTHOR SUMMARY: After application of a gene transcription stimulus, in this case the hormone 17 ß -estradiol, on large populations of cells over a short time period, we focused on quantifying and modeling the frequencies of GREB1 single allele activations. We have established an experimental and computational pipeline to analyze large numbers of high resolution smFISH images to detect and monitor active GREB1 alleles, that can be translatable to any target gene of interest. A key result is that, at the population level, activation of individual GREB1 alleles within the same nucleus do exhibit statistically significant dependencies which we quantify by the mutual information between activation states of pairs of alleles. After noticing that frequencies of joint alleles activations observed over our large cell populations evolve smoothly in time, we have defined a population level stochastic model which we fit to the observed time course of GREB1 activation frequencies. This provided coherent estimates of the mean time between rounds of GREB1 transcription and the mean lifetime of nascent mRNAs. Our algorithmic approach and experimental methods are applicable to many other genes.

Subscapularis tear classification implications regarding treatment and outcomes: consensus decision-making.

Background: Several classifications have been proposed for subscapularis tendon tearing (SCTs); however, there remains a poor agreement between orthopedic surgeons regarding the diagnosis and management of these lesions. Distinguishing the various tear patterns and classifying them with some prognostic significance may aid the operating surgeon in planning appropriate treatment. Purpose: The purpose of this study was to outline the current literature regarding SCT classification and treatment and conduct a survey among shoulder and elbow surgeons to identify the approaches regarding surgical decision-making for these injuries. Methods: In this systematic review, we analyzed 12 articles regarding the subscapularis tendon tear classification and implications regarding treatment plans and outcomes. In addition, 4 international experts in subscapularis repair surgery participated in the development of a questionnaire form that was distributed to 1161 ASES members. One hundred sixty five surgeons participated and chose whether they agree, disagree, or abstain for each of the 32 statements in 4 parts including indications/contraindications, treatment plan, and the factors affecting outcomes in the survey. Results: Classification criteria were extremely variable with differing recommendations and descriptions of tear morphology; most were based on tear size, associated shoulder pathology, or lesser tuberosity footprint exposure. Considering the multiple classification systems and the overall poor agreement regarding SCT management, our study found that the most widely agreed upon (more than 80%) statements included early surgery is advised for traumatic SCT, chronic degenerative SCT (without fatty infiltration) associated with acute supraspinatus tear is a candidate for repair, and rotator cuff arthropathy is a contraindication for SCT repair. Conclusion: Our study was able to identify both patient and tear characteristics that are well agreed upon among surgeons in the treatment of these injuries. Lafosse classification is generally widely accepted; however, it needs to be improved by some additions. Continued collaboration among surgeons is needed to establish an acceptable and broadly applicable classification system for the management of these injuries.

Successful Return to Sport and Daily Activities After Suture Augmentation of Both the Anterior Talofibular Ligament and Calcaneofibular Ligament.

Purpose: To evaluate the return to sport and daily activities in addition to clinical outcomes after modification of the Brostöm repair, specifically using suture augmentation for concomitant fixation of both the anterior talofibular ligament and calcaneofibular ligament. Methods: Patients who had grade III ankle sprains and lateral ankle instability, all of whom failed supervised conservative management, were included. Patients underwent a modified Broström procedure consisting of suture augmentation for both the anterior talofibular ligament and calcaneofibular ligament. For clinical outcome evaluation, Foot and Ankle Ability Measure (FAAM) and Karlsson-Peterson Scoring System for Ankle Function questionnaires coupled with questions regarding time of return to sport and level of sports activity were used. Results: Thirty-one patients were included. The differences in preoperative and postoperative FAAM scores for both the Activities of Daily Living subscale and Sports subscale were significant (P < .001). The FAAM Activities of Daily Living score improved from an average of 46.06 preoperatively to 77.49 postoperatively (P < .001, 99% confidence interval, 26.4-36.4). The FAAM Sports score improved from an average of 4 preoperatively to 19.31 postoperatively (P < .001, 99% confidence interval, 11.6-19.0). For the Karlsson-Peterson Scoring System for Ankle Function, the surveyed population reported a mean of 82.74 points out of 100 post-op (standard deviation 20.14). The mean time to return to sport activity was 5.72 months. Mean follow-up time was 24.12 months. Conclusions: This variant Broström procedure with suture anchors and augmentation of both the anterior talofibular ligament and calcaneofibular ligament was effective in helping patients return to their preinjury functionality level in both daily life and sports activity. Level of Clinical Evidence: Level IV, therapeutic case series.

Ankle Distraction Arthroplasty: A Survivorship Review and Meta-Analysis.

Multiple treatments exist for ankle osteoarthritis. Ankle arthrodesis is the gold standard in late-stage osteoarthritis, but sacrifices range of motion and risks nonunion. Total ankle arthroplasty is typically reserved for low-demand patients as the long-term outcomes are poor. Ankle distraction arthroplasty is a joint sparing procedure which utilizes external fixator frame to unload the joint. This promotes chondral repair and improves function. This study aimed to organize clinical data and survivorship in published papers and direct further research efforts. Thirty-one publications were evaluated and 16 were included in the meta-analysis. The Modified Coleman Methodology Score was used to assess quality of the individual publications. Random effects models were used to estimate the failure risk after ankle distraction arthroplasty. Ankle Osteoarthritis Score (AOS), American Orthopedic Foot and Ankle Score (AOFAS), Van Valburg, and Visual Analog Scores (VAS) all improved postoperatively. Random effects model analysis revealed an overall failure ratio of 11% (95% CI: 7%-15%; p value ≤ .001; I2 = 87.01%) after 46.68 ± 7.17 months follow up, 9% (95% CI: 5%-12%; p value≤0.001 I2=81.59%) with less than 5 years follow-up and 28% (95% CI: 16%-41%; p value≤0.001 I2=69.03%) for patients with more than 5 years follow-up. Ankle Distraction Arthroplasty has promising short to intermediate term outcomes which makes this a reasonable treatment option to delay joint sacrificing surgery. The selection of the optimal candidates and consistent technique would improve research and subsequently outcomes. Based on our meta-analysis, negative prognostic factors include female sex, obesity, ROM < 20°, leg muscle weakness, high activity level, low preoperative pain levels, higher preoperative clinical scores, inflammatory arthritis, septic arthritis, and deformity.

Accuracy of radiographic techniques in detection of the calcaneofibular ligament calcaneal insertion for lateral ankle ligament complex surgery.

BACKGROUND: Grade III ankle sprains that fail conservative treatment can require surgical management. Anatomic procedures have been shown to properly restore joint mechanics, and precise localization of insertion sites of the lateral ankle complex ligaments can be determined through radiographic techniques. Ideally, radiographic techniques that are easily reproducible intraoperatively will lead to a consistently well-placed CFL reconstruction in lateral ankle ligament surgery. PURPOSE: To determine the most accurate method to locate the calcaneofibular ligament (CFL) insertion radiographically. METHODS: MRIs of 25 ankles were utilized to identify the "true" insertion of the CFL. Distances between the true insertion and three bony landmarks were measured. Three proposed methods (Best, Lopes, and Taser) for determining the CFL insertion were applied to lateral ankle radiographs. X and Y coordinate distances were measured from the insertion found on each proposed method to the three bony landmarks: the most superior point of the postero-superior surface of the calcaneus, the posterior most aspect of the sinus tarsi, and the distal tip of the fibula. X and Y distances were compared to the true insertion found on MRI. All measurements were made using a picture archiving and communication system. The average, standard deviation, minimum, and maximum were obtained. Statistical analysis was performed using repeated measures ANOVA, and a post hoc analysis was performed with the Bonferroni test. RESULTS: The Best and Taser techniques were found to be closest to the true CFL insertion when combining X and Y distances. For distance in the X direction, there was no significant difference between techniques (P = 0.264). For distance in the Y direction, there was a significant difference between techniques (P = 0.015). For distance in the combined XY direction, there was a significant difference between techniques (P = 0.001). The CFL insertion as determined by the Best method was significantly closer to the true insertion compared to the Lopes method in the Y (P = 0.042) and XY (P = 0.004) directions. The CFL insertion as determined by the Taser method was significantly closer to the true insertion compared to the Lopes method in the XY direction (P = 0.017). There was no significant difference between the Best and Taser methods. CONCLUSION: If the Best and Taser techniques can be readily used in the operating room, they would likely prove the most reliable for finding the true CFL insertion.

Opening wedge high tibial osteotomy for medial compartment knee osteoarthritis: Planning and improving outcomes: Case series and literature review.

Background: Opening wedge high tibial osteotomy (OWHTO) is a safe surgical procedure to treat medial compartmental osteoarthritis caused by a varus deformity. Over-correction of this varus deformity can lead to lateral compartment over-loading. In our study, we planned our correction by using the mechanical axis deviation (MAD). Purpose: The purpose of this study is to evaluate the clinical and radiological results of OWHTO based on planning using the MAD measurements. Study Design: Retrospective Case Series. Methods: 14 patients with Kellgren- Lawrence classification (KL) grade 3 or above underwent OWHTO, with plans to have the mechanical axis pass through 5-15 mm lateral to the center of the tibial plateau. Pre-operative and post-operative radiographic measurements were made and compared using the student t-test. SF-36 scores were obtained for clinical performance. Results: Our patients experienced MAD from 25.9 mm medial to the center of the tibial plateau pre-operatively to 12.7 mm lateral to the center of the plateau post-operatively. The mean change in MAD was 38.7 mm (p < 0.0001). The accuracy of our correction compared to the planned MAD was 98.3%. The mechanical axis angle shifted from 7.35° of varus to 3.5° of valgus (p < 0.0001). All patients had post-operative alignments of 1-6° of valgus, with 11 of out the 14 patients with alignments less than 5° of valgus, preventing over-loading of the lateral compartment. Conclusion: Using MAD measurements is an accurate planning method for OWHTO that corrects varus deformity without over-loading the lateral compartment, and leads to improved clinical outcomes.

Pseudomeniscus after knee arthroplasty: A case series for arthroscopic management of this problem and systematic review of literature.

Introduction: Most patients undergoing total knee arthroplasty (TKA) experience favorable outcomes. Some patients, however, experience prolonged post-operative knee pain and tenderness at the joint line. This has been attributed in some cases to soft tissue impingement due to pseudomeniscus. The purpose of this study is to evaluate patient outcomes for arthroscopic excision of pseudomeniscus for persistent knee pain after TKA and to perform a review of literature for pseudomeniscus after knee arthroplasty. Methods: A retrospective analysis of patients undergoing arthroscopy to remove soft tissue causing persistent knee pain after previous TKA was performed. Outcome scores were asked at three time points: prior to knee arthroplasty, prior to arthroscopy, and post-arthroscopy at final follow-up. Subjective satisfaction with surgery and willingness to repeat procedures were also recorded. A two-tailed distribution paired t-test was used to determine statistical significance (p < 0.05). We also performed a review of the literature for pseudomeniscus complications for comparison. Results: Nine out of eleven patients were considered eligible to be assessed for post-operative satisfaction. Seven out of nine patients reported complete satisfaction and eight participants stated they would undergo the procedures again if they have to. Among 9 included patients, five patients have successfully completed the clinical score evaluation survey. The mean age of the patients with clinical score evaluation at the time of TKA was 61 years (range, 53-72) and the time between TKA and undergoing arthroscopy was 8 months (range, 5-13). The average follow-up period for patient-determined assessment after the arthroscopic procedure was 71 months (range, 16-115). All 5 patients reported improved Oxford Knee Scores (p=0.017), Western Ontario and McMaster Universities Osteoarthritis Index (p=0.023), and pain scores (p=0.018) comparing pre-arthroscopy to post-arthroscopy at follow-up. Conclusion: Arthroscopic removal of pseudomeniscus after TKA provides promising results in patients who experience persistent knee joint line pain and tenderness. Considering our results and review of literature, we recommend including pseudomeniscus in the differential for post arthroplasty knee pain. Study design: Case series with a review of literature.

Structural and charge transfer properties of ion intercalated 2D and bulk ice.

Ion trapping at the nanoscale within low-dimensional and bulk ice and their corresponding hydration properties are studied using ab initio techniques. We study the structural and charge transfer properties of ion intercalated two-dimensional (2D) and bulk ice and the corresponding ion hydration properties. We found that (i) the nanochannel size and ionic radius are two important factors that control the spatial distribution of hydrated ions, (ii) the alkali metal and halide ions are located in the center of the graphene-made nanochannel of size ≃6.5 Å, whereas in the nanochannel with size ≃9 Å, large (K+, Rb+, Cl-, Br-, and I-) and small (Li+, Na+, and F-) ions are located in different positions, (iii) the binding energy decreases with increase in the ionic radius, (iv) the hydration of ions decreases for large ions within 2D ice, giving a reduction in coordination number and allowing dehydration of large ions, and (v) the charge transfer mechanism is found to be different for large and small ions.

Evaluation of COVID-19 pandemic spreading using computational analysis on nonlinear SITR model.

The main purpose of present paper is to investigate the nonlinear model of COVID-19 (novel coronavirus) computationally. The SITR model is designed according to four classifications of Susceptible (S), Infectious (I), Treatment (T) and Recovered (R). Two convenient and effective numerical techniques namely the Adams-Bashforth Method (ABM) and Milne-Simpson Method (MSM) are employed to analyze the epidemic model. The influences of the contact rate parameter (ß), recovery parameter (µ) and death parameter (α) on the variables including S, I and R are studied comprehensively. The obtained findings indicate that by increasing the contact rate parameter the infectious and recovered categories enhance but the susceptible mechanism decreases.

Electronic Properties of Oxidized Graphene: Effects of Strain and an Electric Field on Flat Bands and the Energy Gap.

A multiscale modeling and simulation approach, including first-principles calculations, ab initio molecular dynamics simulations, and a tight binding approach, is employed to study band flattening of the electronic band structure of oxidized monolayer graphene. The width of flat bands can be tuned by strain, the external electric field, and the density of functional groups and their distribution. A transition to a conducting state is found for monolayer graphene with impurities when it is subjected to an electric field of ∼1.0 V/Å. Several parallel impurity-induced flat bands appear in the low-energy spectrum of monolayer graphene when the number of epoxy groups is changed. The width of the flat band decreases with an increase in tensile strain but is independent of the electric field strength. Here an alternative and easy route for obtaining band flattening in thermodynamically stable functionalized monolayer graphene is introduced. Our work discloses a new avenue for research on band flattening in monolayer graphene.

Adaptable transmitter for discrete and continuous variable quantum key distribution.

We present a versatile transmitter capable of performing both discrete variable and continuous variable quantum key distribution protocols (DV-QKD and CV-QKD, respectively). Using this transmitter, we implement a time-bin encoded BB84 DV-QKD protocol over a physical quantum channel of 47 km and a GG02 CV-QKD protocol with true local oscillator over a 10.5 km channel, achieving secret key rates of 4.1 kbps and 1 Mbps for DV- and CV-QKD, respectively. The reported transmitter scheme is particularly suitable for re-configurable optical networks where the QKD protocol is selected to optimize the performance according to the parameters of the links.

Proximal tibial osteotomy for genu varum: Radiological evaluation of deformity correction with a plate vs external fixator.

BACKGROUND: High tibial osteotomy (HTO) is a well-known procedure for the correction of knee varus. The purpose of this study was to compare the radiological results and accuracy of deformity correction performed using two different techniques: acute opening wedge correction using a plate and gradual correction with a monolateral external fixator. AIM: To compare of the radiological results of two different techniques: acute opening wedge correction (a plate and screw) and gradual correction (external fixator). METHODS: A total of 43 patients with plates and 36 patients with external fixators were included. All patients had moderate uniplanar varus deformities. We measured radiographic parameters, including the mechanical axis deviation (MAD), medial proximal tibial angle (MPTA), Caton-Deschamps Index (CDI), posterior proximal tibial angle, and joint line obliquity angle (JLOA). The accuracy of MAD correction was calculated based on a correction goal of neutral or overcorrection for medial compartment arthritis. RESULTS: Demographics including age, body mass index, sex, and preoperative deformities were similar between the groups. The MAD significantly improved from 23.6 mm medial to the midline (SD = 8.2 mm) to 6.9 mm lateral to the midline (SD = 5.4 mm) (P < 0.001). The accuracy of MAD correction did not differ between the groups and was 96.1% (SD = 8.1%) in the plate group and 98.2% (SD = 5.2%) in the external fixator group (P = 0.18). The MPTA significantly improved from 83.9° (SD = 2.9°) to 90.9° (SD = 3.3°) (P < 0.001), and the change was similar between the groups. Differences were noted in patella height, with a CDI change of -19.2% (SD = 13.7%) and 3.1% (SD = 8.0%) for the plate and external fixator groups, respectively (P < 0.001). The change in JLOA was 1.6 degrees (SD = 1.1 degrees) and 0.9 degrees (SD = 0.9 degrees) for the plate and external fixator groups, respectively (P = 0.04). CONCLUSION: Reliable correction of moderate varus alignment was achieved with both the acute opening wedge technique with a plate and the gradual monolateral external fixator technique. The patellar height decreased with the open wedge plate technique. Joint line obliquity decreased to a greater degree with the open wedge plate technique, perhaps as a result of medial collateral ligament release. The appropriate technique should be selected based on surgeon and patient preferences; however, external fixation may be a better choice when the preservation of patellar height is deemed important.

Thermodynamically stable polymorphs of nitrogen-rich carbon nitrides: a C3N5 study.

We have carried out an extensive search for stable polymorphs of carbon nitride with C3N5 stoichiometry using the minima hopping method. Contrary to the widely held opinion that stacked, planar, graphite-like structures are energetically the most stable carbon nitride polymorphs for various nitrogen contents, we find that this does not apply for nitrogen-rich materials owing to the high abundance of N-N bonds. In fact, our results disclose novel morphologies with moieties not previously considered for C3N5. We demonstrate that nitrogen-rich compounds crystallize in a large variety of different structures due to particular characteristics of their energy landscapes. The newly found low-energy structures of C3N5 have band gaps within good agreement with the values measured in experimental studies.

Artificial neural networks for the kinetic energy functional of non-interacting fermions.

A novel approach to find the fermionic non-interacting kinetic energy functional with chemical accuracy using machine learning techniques is presented. To that extent, we apply machine learning to an intermediate quantity rather than targeting the kinetic energy directly. We demonstrate the performance of the method for three model systems containing three and four electrons. The resulting kinetic energy functional remarkably accurately reproduces self-consistently the ground state electron density and total energy of reference Kohn-Sham calculations with an error of less than 5 mHa. This development opens a new avenue to advance orbital-free density functional theory by means of machine learning.

New strontium titanate polymorphs under high pressure.

We report six new dynamically stable structures of SrTiO3 at various pressures ranging from 0 to 200 GPa. These structures were found by exploring the enthalpy surface with the Minima Hopping structure prediction method. The potential energy surface was generated by a machine learned potential, the charge equilibration via neural network technique (CENT), based on an extensive training data set of highly diverse SrTiO3 periodic and cluster structures. All our CENT structures were validated at the level of density functional theory. For our new structures, we performed phonon calculations and NVT molecular dynamics calculations to investigate their dynamical stability. Finally, X-ray diffraction patterns were simulated to help to identify our predicted structures in experiments.

Staged Bilateral Total Knee Arthroplasty: When Should the Second Knee be Replaced?

BACKGROUND: Bilateral total knee arthroplasty (BTKA) under the same anesthesia (simultaneous) or staged are options for patients with end-stage arthritis of the knee that carries advantages and limitations. Not all patients are candidates for simultaneous BTKA, and therefore, surgeons prefer to stage the two TKAs. The optimal safe interval between two TKAs is not known. The present systematic review aimed to determine the optimal time interval between the two stages of BTKA. METHODS: Pubmed and Scopus databases were searched to identify publications from January 1979 to November 2017 in English that compared the outcomes of staged BTKA performed using various time intervals between the two TKAs. Data on systemic and local complications following staged BTKA were extracted, and the pooled data were analyzed to adjust for age. RESULTS: In total, 23 studies that enrolled 117,090 patients undergoing staged BTKA were included in this systematic review. A significant increase was observed in the incidence of myocardial infarction (OR=8.4 and 8.32), other cardiac complications (OR=17.71 and 18.18), deep vein thrombosis (OR=4.72 and 4.89), pneumonia (OR=3.37 and 3.45), and knee revision (OR=3.73 and 4.14) in patients undergoing the second TKA within 30 days or 90 days of the first TKA. However, the replacement of the second knee within this time interval was associated with a significantly lower risk of pulmonary embolism (OR=0.145 and 0.128), superficial (OR=0.14 and 0.79) and deep knee infection (OR=0.0 and 0.0), as well as vascular complications (OR=0.0 and 0.42). CONCLUSION: Time interval of less than 30 or 90 days between two TKAs performed in patients with BTKA was associated with a higher risk of systematic complications. However, the shorter time intervals between the two TKA may reduce the risk of other complications. This information may help surgeons' council patients better when deciding on the optimal time interval between two TKAs.

Subtalar distraction arthroplasty with bone marrow aspirate concentrate (BMAC), preliminary results of a new joint preservation technique.

INTRODUCTION: Isolated subtalar osteoarthritis (OA) is a debilitating condition usually occurring after trauma and particularly in the setting of an intraarticular calcaneal fracture. Currently, subtalar (talo-calcaneal joint) fusion surgery is the treatment of choice in managing subtalar OA after failure of conservative treatment. Unfortunately, subtalar fusion eliminates joint motion and increases the load over the adjacent midfoot and ankle joints, which affects the outcome of the surgery over time. Popular in the ankle, distraction arthroplasty offers another joint-preserving option, particularly important for active patients. In contrast to fusion as a salvage procedure, subtalar distraction arthroplasty allows the possibility of maintaining the function of the arthritic subtalar joint while reducing pain and improving the overall function of the foot and ankle. METHODS: We performed subtalar distraction arthroplasty using a circular external fixator combined with BMAC on seven patients with symptomatic and refractory subtalar OA. All these patients were interested in an alternative to fusion. We obtained clinical and radiographic data before and after surgery. Ankle Osteoarthritis Score (AOS) and the Marijnissen Distraction Clinical Score (MDCS) were obtained before surgery, after one year, and at latest follow-up. RESULTS: The average age was 56 years (range 45-69). The mean duration of post-operative follow-up was 35.4 months (range 15.2-53.5). The inversion of the ankle joint changed from 16.9° (10°-25°) pre-operatively to 14.3° (10°-20°) post-operatively (P = 0.28), and the eversion from 5.6° (0°-10°) to 10.0° (0°-20°) (P = 0.17). We found an increase in subtalar joint space from 1.4 mm (0-3) to 2.6 mm (2-4) before and after surgery (P = 0.01), respectively. Finally, Pixel Density Ratio (PDR) increased from 0.87 (0.66-1.30) to 1.01 (0.89-1.18) (P = 0.19). Compared to pre-operative conditions, we observed a decrease in subchondral sclerosis on X-ray in all cases post-operatively. The AOS score for ankle pain improved from 58.8 (47-74) to 15.1 (0-31) (p < 0.01). The AOS score for ankle disability improved from 68.2 (57-81) to 16.1 (0-43.5) (p < 0.001). We found improvement in the MDCS over time for all measured parameters. The clinical condition improved from 1.4 (0-2) to 0.8 (0-2) after one year and to 0.3 (0-2) at the latest follow-up (p < 0.001). Mobility was measured as ROM in the treated ankle relative to each patient's contralateral ankle. This increased from 35% (0-100) to 66% (15-120) to 76% (15-100) (p = 0.059). Function improved from 2.3 (0-3) to 1.3 (0-3) to 0.6 (0-3) (p < 0.001). Pain decreased from 7.4 (2-10) to 4.4 (2-8) to 2.1 (0-7) (p < 0.01). Complications include one patient with sensory neuralgia. CONCLUSIONS: Preliminarily, results of subtalar distraction arthroplasty as a new joint preservation technique are encouraging. Our research suggests the possibility of subtalar distraction arthroplasty as an effective treatment for symptomatic subtalar OA. Furthermore, this new operation does not eliminate the possibility of a future surgery like fusion. Subtalar distraction arthroplasty can be helpful in the management of subtalar OA in active patients who desire preservation of foot and ankle motion.

Does osteoporosis increase marginal bone loss around dental implants in the posterior of the maxilla?

Osteoporosis is caused by an imbalance in bone remodelling. The aim of this study was to compare the marginal bone loss (MBL) around dental implants placed in the posterior maxilla between osteoporotic and non-osteoporotic female patients. This was a prospective cohort study. Female patients needing a dental implant restoration in the posterior maxilla were included. Dual-energy X-ray absorptiometry was performed and the T-score recorded. MBL was measured at 12 months after loading. The patients were assigned to one of two groups: group 1, osteoporotic (T-score ≥2.5); group 2, non-osteoporotic (T-score <2.5). In this study, osteoporosis was the primary predictor variable and MBL was the outcome variable. The mean MBL was compared between the two groups using an independent t-test. Pearson's correlation test was applied to identify any correlation between the T-score and MBL. Ninety female patients were studied, 44 in group 1 and 46 in group 2. The mean MBL was 1.20±0.29mm in group 1 and 0.87±0.15 in group 2; this difference in mean MBL was statistically significant (P=0.001). There was a correlation between T-score and MBL (P=0.001). Despite the correlation between T-score and MBL, this study did not provide enough evidence to prove any causal relationship between MBL and osteoporosis.