Secondary osteoporosis prevention: three-year outcomes from a Fracture Liaison Service in elderly hip fracture patients.

BACKGROUND: Hip fractures are the most serious fragility fractures due to their associated disability, higher hospitalization costs and high mortality rates. Fracture Liaison Service (FLS) programs have enhanced the management of osteoporosis-related fractures and have shown their clinical effectiveness. AIMS: To analyze the effect of the implementation of a FLS model of care over the survival and mortality rates following a hip fracture. METHODS: We conducted a prospective cohort study on patients over 60 years of age who suffered a hip fracture before and after the implementation of the FLS in our center (between January 2016 and December 2019). Patients were followed for three years after the index date. Mortality, complications and refracture rates were compared between the two groups using a Multivariate Cox proportional hazard model. RESULTS: A total of 1366 patients were included in this study (353 before FLS implementation and 1013 after FLS implementation). Anti-osteoporotic drugs were more frequently prescribed after FLS implementation (79.3% vs 12.5%; p < 0.01) and there was an increase in adherence to treatment (51.7% vs 30.2%; p < 0.01). A total of 413 (40.8%) patients after FLS implementation and 141 (39.9%) individuals before (p = 0.47) died during the three-years follow-up period. A second fracture occurred in 101 (10.0%) patients after FLS implementation and 37 (10.5%) individuals before (p = 0.78). Patients after the implementation of the FLS protocol had a lower all cause one-year mortality [adjusted Hazard Ratio (HR) 0.74 (0.57-0.94)] and a decreased risk of suffering a second osteoporotic fracture [adjusted HR 0.54 (0.39-0.75) in males and adjusted HR 0.46 (0.30-0.71) in females]. CONCLUSIONS: The implementation of a FLS protocol was associated with a lower all-cause one-year mortality rate and a higher survivorship in elderly hip fracture patients. However, no three-year mortality rate differences were observed between the two groups. We also found a reduction in the complication and second-fracture rates.

The Use of ß-Blockers and the Risk of Undergoing a Knee Arthroplasty: A Nested Case-Control Study.

BACKGROUND: Research has indicated that ß-blockers may downregulate various inflammatory mediators that are involved in osteoarthritis (OA). The objective of this study was to analyze the likelihood of total knee arthroplasty (TKA) among patients with OA who were being treated with ß-blockers. METHODS: A nested case-control study was conducted with use of clinical records from our institutional database. We included patients who attended our outpatient clinic with a history of new-onset knee pain between 2010 and 2019. The case group included individuals who had undergone primary TKA between 2018 and 2019, whereas the control group included subjects who had not undergone TKA. Controls were matched by date of birth ±2 years, sex, calendar time (first outpatient visit ±1 year), and the grade of arthritis; the control-to-case ratio was 1:1. Adherence to ß-blocker use was measured with use of the proportion of days covered (PDC) (i.e.,<0.25, ≥0.25 to <0.75, ≥0.75), and the cumulative effect was measured on the basis of the total number of years of treatment with ß-blockers. A binary logistic regression analysis adjusted to potential confounders was carried out to assess the risk of TKA associated with the intake of ß-blockers. RESULTS: A total of 600 patients were included (300 in the case group and 300 in the control group). Compared with non-users, any use of ß-blockers during the follow-up period was associated with a reduction in the likelihood of undergoing TKA (adjusted odds ratio [OR], 0.51; 95% confidence interval [CI], 0.34-0.77). The adjusted ORs for the use of selective ß1-blockers and nonselective ß1-blockers were 0.69 (95% CI, 0.36 to 1.31) and 0.42 (95% CI, 0.24 to 0.70), respectively. The adjusted ORs for any recent use, PDC of <0.25, PDC of ≥0.25 to <0.75, and PDC of ≥0.75 were 0.65 (95% CI, 0.51 to 0.99), 0.62 (95% CI, 0.21 to 1.85), 0.32 (95% CI, 0.09 to 1.22), and 0.55 (95% CI, 0.34 to 0.88), respectively. Regarding the cumulative effect of ß-blockers, the adjusted ORs for the use for <1 year, ≥1 to <5 years, and ≥5 years were 0.41 (95% CI, 0.20 to 0.85), 0.52 (95% CI, 0.21 to 1.33), and 0.36 (95% CI, 0.22 to 0.60), respectively. CONCLUSIONS: The use of nonselective ß-blockers was associated with a lower likelihood of undergoing TKA. Patients treated for prolonged periods were at a lower likelihood for undergoing TKA. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Admission criteria and academic performance in medical school.

BACKGROUND: Different variables have been used to predict the academic performance of students in medical schools. The aim of this study was to assess the effect of demographics, admission system, and high-school background on the academic performance of medical students. METHODS: We conducted this longitudinal cohort study on 808 students admitted to the Faculty of. Medicine at the University of Jordan (Amman, Jordan), in the years 2012 and 2013. Admission pathway, and academic performance data were collected and analyzed. RESULTS: A total of 808 students [i.e., 426 (52.7%) females, and 382(47.3%) males] were identified. Admitted students were holding 17 different types of high school degrees, and were accepted through 6 different quota pathways (open competition [National unified admission], underprivileged ["Makrumah"], parallel, children of university staff, international students, and others). Students admitted through the open competition and the underprivileged quota(Makrumah) were more likely to graduate on time and had higher graduation grades while students admitted through the parallel, international and others quota were more likely to fail and had lower graduation grades. Regarding highs school degrees, the students that were more likely to graduate were those with IB and the Jordanian high school degrees. The highest graduation GPA was for IB students followed by SAT, IGCSE as well as Jordanian and Syrian high school degrees respectively. IB, Jordanian, Kuwaiti and IGSC high school grades were significantly correlated with the graduation GPA. CONCLUSIONS: Admission criteria such as type of high school degree and grades as well as admission pathways can predict the likelihood to graduate and the graduation GPA of medical students. Open competition and underprivileged admission pathways as well as IB, IGCSE and Jordanian high school degrees seem to be better predictors of student performance in the medical school.

Facemask wearing does not impact neuro-electrical brain activity.

Given the massive use of facemasks (FMs) during the covid-19 pandemic, concerns have been raised regarding the effect of FMs wearing on overall health. This study aimed at evaluating the effect of surgical FM on brain neuro-electrical activity. Electroencephalography (EEG) background frequency (BGF) and background amplitude (BGA) was performed on 30 volunteers before (baseline), during and after wearing a FM for 60 min. Measurements were done during normal ventilation, hyperventilation and post-hyperventilation (PHVR). Blood gas levels were assessed at baseline and after FM use. EEG analysis concerning baseline (without FM) (BGA), was 47.69 ± 18.60 µV, wearing FM, BGA was 48.45 ± 17.79 µV, post FM use BGA was 48.08 ± 18.30 µV. There were no statistically significant differences between baseline BGA and BGA under FM and post FM. BGF, Baseline data were 10.27 ± 0.79, FM use 10.30 ± 0.76 and post FM use was 10.33 ± 0.76. There were no statistically significant differences between baseline BGF and BGF under FM and post FM. Venous blood gases, and peripheral oxygen saturation were not significantly affected by FM use. Short-term use of FM in young healthy individuals has no significant alteration impact on brain's neuro-electrical activity.

Proton Pump Inhibitors and the Risk of Early Aseptic Loosening in Hip and Knee Arthroplasty.

Introduction: The use of proton pump inhibitors (PPIs) has been associated with a higher risk of osteoporotic fractures and non-unions rates. However, the relation between the use of PPIs and the development of aseptic loosening in arthroplasty procedures has not been studied. The objective of this study is to analyze the relation between the use of PPIs, and the risk of early aseptic loosening in total knee arthroplasty (TKA) and total hip arthroplasty (THA). Materials and methods: A nested case-control study was conducted on patients who were subjected THA or TKA in our center between 2010 and 2014. Cases were patients subjected to revision surgery due to early aseptic loosening during the study period. Cases were matched with controls who did not require any type of revision surgery by type of joint replacement (THA/TKA), gender, age (+/- 2 years), and follow-up time (±6 months). Odds Ratios were adjusted to potential confounders. Results: The crude and adjusted ORs (95% CI) of undergoing revision surgery for aseptic loosening following primary total knee arthroplasty or total hip arthroplasty, were 6.25 (2.04-19.23) and 6.10 (1.71-21.73), respectively, for any use PPIs compared with non-users. Crude and adjusted ORs, were 11.6 (2.93-45.88) and 17.1 (2.41-121.66), respectively, for patients with a Proportion of Days Covered (PDC) for PPIs <.5 (Table 2). In addition, the crude and adjusted ORs of undergoing revision surgery, were 5.05 (1.59-16.02) and 5.01 (1.36-18.44), respectively, for patients with a PDC for PPIs ≥.5. Discussion: These results suggest that PPIs should be used with caution in patients with TKA and THA, and that the use of these drugs should not be prolonged unless there was a justifiable indication. Conclusions: The use of PPIs and was associated with a higher risk of early aseptic loosening in patients subjected to THA and TKA.

Lateral Meniscus Height and ACL Reconstruction Failure: A Nested Case-Control Study.

Previous work has shown that the morphology of the knee joint is associated with the risk of primary anterior cruciate ligament (ACL) injury. The objective of this study is to analyze the effect of the meniscal height, anteroposterior distance of the lateral tibial plateau, and other morphological features of the knee joint on risk of ACL reconstruction failure. A nested case-control study was conducted on patients who underwent an ACL reconstruction surgery during the period between 2008 and 2015. Cases were individuals who failed surgery during the study period. Controls were patients who underwent primary ACL reconstruction surgery successfully during the study period. They were matched by age (±2 years), gender, surgeon, and follow-up time (±1 year). A morphological analysis of the knees was then performed using the preoperative magnetic resonance imaging scans. The anteroposterior distance of the medial and lateral tibial plateaus was measured on the T2 axial cuts. The nonweightbearing maximum height of the posterior horn of both menisci was measured on the T1 sagittal scans. Measurements of the medial and lateral tibial slope and meniscal slope were then taken from the sagittal T1 scans passing through the center of the medial and lateral tibial plateau. A binary logistic regression analysis was done to calculate crude and adjusted odds ratios (ORs) estimates. Thirty-four cases who underwent ACL revision surgery were selected and were matched with 68 controls. Cases had a lower lateral meniscal height (6.39 ± 1.2 vs. 7.02 ± 0.9, p = 0.008, power = 84.4%). No differences were found between the two groups regarding the bone slope of the lateral compartment (6.19 ± 4.8 vs. 6.92 ± 5.8, p = 0.552), the lateral meniscal slope (-0.28 ± 5.8 vs. -1.03 ± 4.7, p = 0.509), and the anteroposterior distance of the lateral tibial plateau (37.1 ± 5.4 vs. 35.6 ± 4, p = 0.165). In addition, no differences were found in the medial meniscus height between cases and controls (5.58 ± 1.2 vs. 5.81 ± 1.2, respectively, p = 0.394). There were also no differences between cases and controls involving the medial bone slope, medial meniscal slope, or anterior posterior distance of the medial tibial plateau. Female patients had a higher medial (4.8 degrees ± 3.2 vs. 3.3 ± 4.1, p = 0.047) and lateral (8.1 degrees ± 5.1 vs. 5.6 degrees ± 5.6, p = 0.031) tibial bone slope, and a lower medial (5.3 mm ± 1.0 vs. 6.1 mm ± 1.2, p = 0.001) and lateral (6.6 ± 1.0 vs. 7.0 ± 1.2, p = 0.035) meniscus height, and medial (4.3 ± 0.4 vs. 4.8 ± 0.4, p =0.000) and lateral (3.3 ± 0.3 vs. 3.9 ± 0.4, p = 0.000) anteroposterior distance than males, respectively.The adjusted OR of suffering an ACL reconstruction failure compared to controls was 5.1 (95% confidence interval [CI]: 1.7-14.9, p = 0.003) for patients who had a lateral meniscus height under 6.0 mm. The adjusted OR of suffering an ACL reconstruction failure was 2.4 (95% CI: 1.0-7.7, p = 0.01) for patients who had an anteroposterior distance above 35.0 mm. Patients with a lateral meniscal height under 6.0 mm have a 5.1-fold risk of suffering an ACL reconstruction failure compared to individuals who have a lateral meniscal height above 6.0 mm. Patients with a higher anteroposterior distance of the lateral tibial plateau also have a higher risk of ACL reconstruction failure.

Non-union and use of proton pump inhibitors in the treatment of femoral and tibial shaft fractures: a nested case-control study.

BACKGROUND: Proton pump inhibitors (PPIs) are one of the most frequently used drugs worldwide. Previous research has shown that they could increase the risk of fracture and interfere with the fracture healing process. In this study, we analyzed the effect of PPIs on the risk of fracture non-union in patients with femoral and tibial shaft fractures. METHODS: A case-control study was conducted at our institution, including a total of 254 patients who underwent fixation surgery for a femoral or tibial shaft fracture between January 2012 and December 2017. We defined cases as patients who experienced a delayed union (case group A; n = 44), or non-union (cases group B; n = 12). Cases were matched by age, sex, and fractured bone, to 144 controls who did not experience delayed fracture union and did not require further procedures. A conditional logistic regression analysis was performed adjusted to potential confounders, and to the proportion of days covered (PDC) with PPIs. RESULTS: Adjusted ORs (95% CI) for undergoing a nail dynamization following a tibial or femoral shaft fracture were 1.38 (0.70-2.65) for any use PPIs. Patients with a longer PPI treatment courses (PDC ≥ 0.5) had an adjusted OR of 1.86 (0.70-4.76) for undergoing nail dynamization when compared with controls. Contrastingly, patients with a PDC < 0.5 had an adjusted OR of 1.03 (0.43-2.48). The adjusted OR (95% CI) for undergoing additional surgical procedures due to non-union was 4.5 (0.62-32.8) for any use of PPIs, and 12.3 (1.9-81.0) in patients with a PDC ≥ 0.5. CONCLUSIONS: A prolonged use of PPIs use was associated with a higher risk of fracture non-union in tibial and femoral shaft fractures.

A Prediction Model for Primary Anterior Cruciate Ligament Injury Using Artificial Intelligence.

BACKGROUND: Supervised machine learning models in artificial intelligence (AI) have been increasingly used to predict different types of events. However, their use in orthopaedic surgery has been limited. HYPOTHESIS: It was hypothesized that supervised learning techniques could be used to build a mathematical model to predict primary anterior cruciate ligament (ACL) injuries using a set of morphological features of the knee. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Included were 50 adults who had undergone primary ACL reconstruction between 2008 and 2015. All patients were between 18 and 40 years of age at the time of surgery. Patients with a previous ACL injury, multiligament knee injury, previous ACL reconstruction, history of ACL revision surgery, complete meniscectomy, infection, missing data, and associated fracture were excluded. We also identified 50 sex-matched controls who had not sustained an ACL injury. For all participants, we used the preoperative magnetic resonance images to measure the anteroposterior lengths of the medial and lateral tibial plateaus as well as the lateral and medial bone slope (LBS and MBS), lateral and medial meniscal height (LMH and MMH), and lateral and medial meniscal slope (LMS and MMS). The AI predictor was created using Matlab R2019b. A Gaussian naïve Bayes model was selected to create the predictor. RESULTS: Patients in the ACL injury group had a significantly increased posterior LBS (7.0° ± 4.7° vs 3.9° ± 5.4°; P = .008) and LMS (-1.7° ± 4.8° vs -4.0° ± 4.2°; P = .002) and a lower MMH (5.5 ± 0.1 vs 6.1 ± 0.1 mm; P = .006) and LMH (6.9 ± 0.1 vs 7.6 ± 0.1 mm; P = .001). The AI model selected LBS and MBS as the best possible predictive combination, achieving 70% validation accuracy and 92% testing accuracy. CONCLUSION: A prediction model for primary ACL injury, created using machine learning techniques, achieved a >90% testing accuracy. Compared with patients who did not sustain an ACL injury, patients with torn ACLs had an increased posterior LBS and LMS and a lower MMH and LMH.

Acetylcholinesterase inhibitors and risk of bleeding and acute ischemic events in non-hypertensive Alzheimer's patients.

INTRODUCTION: Acetylcholinesterase inhibitors (AChEIs) are commonly used to treat mild to moderate cases of Alzheimer disease (AD). To the best of our knowledge, there has been no study estimating the risk of bleeding and cardiovascular events in patients with non-hypertensive AD. Therefore, this study aimed to estimate the association between AChEIs and the risk of bleeding and cardiovascular ischemic events in patients with non-hypertensive AD. METHODS: A nested case-control study was conducted to estimate the risk of bleeding and ischemic events (angina, myocardial infarction [MI], and stroke) in patients with AD. This study was conducted using the UK Clinical Practice Research Datalink and Hospital Episode Statistics (HES) databases. The study cohort consisted of AD patients ≥65 years of age. The case groups included all AD subjects in the database who had a bleeding or ischemic event during the cohort follow-up. Four controls were selected for each case. Patients were classified as current users or past users based on a 60-day threshold of consuming the drug. Simple and multivariable conditional logistic regression analyses were used to calculate the adjusted odds ratio for bleeding events and cardiovascular events. RESULTS: We identified 507 cases and selected 2028 controls for the bleeding event cohort and 555 cases and 2220 controls for the ischemic event cohort. The adjusted odds ratio (OR) (95% confidence interval [CI]) for the association of AChEI use was 0.93 (0.75 to 1.16) for bleeding events, 2.58 (1.01 to 6.59) for angina, and 1.89 (1.07 to 3.33) for MI. Past users of AChEIs were also at increased risk of stroke (1.51 [1.00 to 2.27]). DISCUSSION: This is the first study assessing the risk of bleeding and cardiovascular events in patients with non-hypertensive AD. Our findings could be of great interest for clinicians and researchers working on AD.

Could vagus nerve stimulation influence bone remodeling?

OBJECTIVES: To investigate the effect of vagus nerve stimulation (VNS) on the bone mineral density (BMD) in epileptic patients. METHODS: A prospective cohort study was conducted on individuals with refractory seizures who underwent VNS surgery between January 2012 and December 2018. BMD was measured preoperatively and between 6 months and one year after surgery. RESULTS: Twenty-one patients (mean age (±SD)=23.6±12.3 years) were recruited for the implantation of a VNS device. The mean absolute increase in lumbar BMD in the 21 patients was 0.04±0.04 g/cm2 resulting in an overall percent increase from baseline of 4.7±6.1%. BMD increased by an amount ≥ the least significant change (LSC) for the lumbar spine in 13 patients (61.9%). The lumbar Z score also increased in these patients from -1.22±1.15 to -0.88±1.22, P=0.006). Pre and Post VNA femoral BMD was measured in only 11 patients and, of those 3 showed a significant increase in BMD, 1 a significant decrease and 7 no change. CONCLUSION: The implantation of a VNS was associated with an increase in lumbar BMD. This study could lead to a new application for VNS in the treatment of osteoporosis.

A Quantifiable Risk Factor for ACL Injury: Applied Mathematics to Model the Posterolateral Tibial Plateau Surface Geometry.

BACKGROUND: The mechanism for traumatic ruptures of the native anterior cruciate ligament (ACL) is frequently a noncontact injury involving a valgus moment with internal rotation of the tibia. The abnormal rotation and translation of the lateral femoral condyle posteroinferiorly relative to the lateral tibial plateau is thought to be related to the geometry of the tibial plateau. PURPOSE/HYPOTHESIS: The purpose of the study was to mathematically model the posterior tibial plateau geometry in patients with ACL injuries and compare it with that of matched controls. The hypothesis was that increased convexity and steepness of the posterior aspect of the lateral plateau would subject knees to higher forces, leading to a potentially higher risk of ACL injury. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We mathematically modeled the posterior curvature of the lateral tibial plateau in 64 patients with ACL injuries and 68 matched controls. Using sagittal magnetic resonance imaging scans of the knee, points on the articular cartilage of the posterolateral tibial plateau were selected and curve-fitted to a power function (y = a × xn ). For coefficient a and coefficient n, both variables modulated the shape of the curve, where a larger magnitude represented an increase in slope steepness. Groups were compared using a Mann-Whitney test and α < .05. RESULTS: There was a significant difference in surface geometry between the patients with ACL injuries and matched controls. The equation coefficients were significantly larger in the patients with ACL injuries: coefficient a (ACL injury, 0.9 vs control, 0.68; P < .0001) and coefficient n (ACL injury, 0.34 vs control, 0.30; P = .07). For coefficient a, there was a 78.9% sensitivity, 77.5% specificity, and odds ratio of 12.6 (95% CI, 5.5-29.0) for ACL injury using a cutoff coefficient a = .78. CONCLUSION: Patients with ACL injuries had a significantly greater posterolateral plateau slope. The steeper drop off may play a role in higher anterior translation forces, coupled with internal rotation torques on the knee in noncontact injury, which could increase ACL strain and predispose to ACL injury.

Rupture of De Novo Middle Cerebral Artery Aneurysm 8 Years After the Clipping of Ruptured M1 Middle Cerebral Artery Aneurysm.

BACKGROUND Development and rupture of a de novo intracranial aneurysm is rare. Little is known regarding its etiology and the appropriate timing of follow-up angiograms after surgical clipping or coiling. CASE REPORT We present a case report of a 39-year-old male smoker with history of hypertension who developed a de novo aneurysm 8 years after surgical clipping of an aneurysm in the middle cerebral artery in the same segment. He presented with neck rigidity and drowsiness. Laboratory analysis did not show blood dyscrasia. Brain computerized tomography showed right temporal lobe hematoma and 4-vessel angiogram demonstrated de novo aneurysm in the same segment of the M1 middle cerebral artery, which was confirmed by intraoperative microsurgical findings. We review the literature on such cases and discuss the pathophysiology, diagnosis, and treatment of this condition. De novo aneurysm, although rare, can develop within days to as long as 10 years after surgical clipping or coiling. CONCLUSIONS This rare case of de novo aneurysm supports follow-up imaging of patients after initial surgical clipping for up to 10 years.

Microsurgical Fenestration of Intracranial Arachnoid Cysts: Volumetric Analysis and Clinical Outcome.

INTRODUCTION: There is paucity of data regarding change in arachnoid cyst (AC) volume following surgery. This study aimed at investigating the clinical outcome of ACs and applying 2 volumetric methods for determination of their volume change post microsurgical fenestration. METHODS: Twenty-one ACs in 20 patients that underwent microsurgical fenestration were analyzed using 2 volumetric methods; the modified McDonald equation and the picture archiving and communication (PAC) system-based method. Patients were followed up for 23 ± 40.3 months. RESULTS: The majority of the patients (13 or 65%) were children. Preoperative symptoms in children were mainly seizures and less commonly headache. Of the 20 patients, 12 (60%) had complete resolution of their preoperative symptoms with 8 (40.0%) showing partial improvement. Volumetric studies showed a mean reduction in AC size of 73.7% in children and 64.4% in adults using the PAC system versus 67.9% in children and 70.5% in adults using the modified McDonald equation method. There was no correlation between the percentage decrease in AC volume post surgery and degree of symptom improvement (49.2 ± 34.3% in patients with complete vs. 60.9 ± 40.3% in patients with only partial resolution of symptoms, p = 0.57). DISCUSSION/CONCLUSION: Microsurgical fenestration is an effective approach for ACs with an excellent clinical outcome apparent in the complete or partial improvement of symptoms in all patients. Volumetric estimates of ACs and their change following surgery are feasible using the modified McDonald or PAC system methods. However, there is no correlation between the percentage decrease in AC volume after surgery and degree of clinical improvement.

Obesity and Meniscal Transplant Failure: A Retrospective Cohort Study.

The purpose of this study was to analyze the effect of obesity and other clinical factors on the outcome of meniscal allograft transplantation (MAT) with transosseous fixation. A retrospective cohort study was performed on patients who underwent a MAT between 2002 and 2017. All the participants had a minimum follow-up period of 24 months. The variables assessed were age at the time of the transplant, side, sex, transplanted meniscus (lateral/medial), body mass index (BMI), smoking status, and previous surgeries. Lysholm, Tegner, and International Knee Documentation Committee (IKDC) test outcomes, and patient satisfaction were recorded. Image assessment was performed using plain standing X-rays and a follow-up magnetic resonance imaging scan. Thirty-five patients fulfilled the inclusion criteria. The mean follow-up time was of 75.7 standard deviation (SD) 43.4 months. Patients with a BMI ≥ 30 underwent medial meniscal transplants (88.9 vs. 42.3%, p = 0.022, respectively) more frequently. Obese patients had a significantly lower IKDC (48.6 SD 19.9 vs. 61.7 SD 13.1, p = 0.038, power: 57.5%) and Lysholm (60.3 SD 19.2 vs. 79.4 SD 14.3, p = 0.004, power: 88.7%) scores compared with nonobese patients. The satisfaction and Tegner scores were also lower in obese patients (55.6 vs. 80.7%, p = 0.136, and 2.8 SD 1.0 vs. 4.0 SD 1.9, p = 0.104, respectively); however, these differences were not statistically significant. Obese patients had higher rates of meniscal transplant failure compared with nonobese patients (adjusted hazard ratio: 11.8 [95% confidence interval: 1.5-91.4]). No differences were observed between obese and nonobese patients regarding age, sex, side, smoking status, and follow-up time. In this study, a BMI ≥ 30 kg/m2 resulted in higher MAT failure rates. Nonobese patients had better knee functional results compared with obese individuals.

Improving the regenerative microenvironment during tendon healing by using nanostructured fibrin/agarose-based hydrogels in a rat Achilles tendon injury model.

AIMS: Achilles tendon injuries are a frequent problem in orthopaedic surgery due to their limited healing capacity and the controversy surrounding surgical treatment. In recent years, tissue engineering research has focused on the development of biomaterials to improve this healing process. The aim of this study was to analyze the effect of tendon augmentation with a nanostructured fibrin-agarose hydrogel (NFAH) or genipin cross-linked nanostructured fibrin-agarose hydrogel (GP-NFAH), on the healing process of the Achilles tendon in rats. METHODS: NFAH, GP-NFAH, and MatriDerm (control) scaffolds were generated (five in each group). A biomechanical and cell-biomaterial-interaction characterization of these biomaterials was then performed: Live/Dead Cell Viability Assay, water-soluble tetrazolium salt-1 (WST-1) assay, and DNA-released after 48 hours. Additionally, a complete section of the left Achilles tendon was made in 24 Wistar rats. Animals were separated into four treatment groups (six in each group): direct repair (Control), tendon repair with MatriDerm, or NFAH, or GP-NFAH. Animals were euthanized for further histological analyses after four or eight weeks post-surgery. The Achilles tendons were harvested and a histopathological analysis was performed. RESULTS: Tensile test revealed that NFAH and GP-NFAH had significantly higher overall biomechanical properties compared with MatriDerm. Moreover, biological studies confirmed a high cell viability in all biomaterials, especially in NFAH. In addition, in vivo evaluation of repaired tendons using biomaterials (NFAH, GP-NFAH, and MatriDerm) resulted in better organization of the collagen fibres and cell alignment without clinical complications than direct repair, with a better histological score in GP-NFAH. CONCLUSION: In this animal model we demonstrated that NFAH and GP-NFAH had the potential to improve tendon healing following a surgical repair. However, future studies are needed to determine the clinical usefulness of these engineered strategies. Cite this article: Bone Joint J 2020;102-B(8):1095-1106.

Composition and characteristics of trabecular bone in osteoporosis and osteoarthritis.

BACKGROUND: Bone strength depends on multiple factors such as bone density, architecture and composition turnover. However, the role these factors play in osteoporotic fractures is not well understood. PURPOSE: The aim of this study was to analyze trabecular bone architecture, and its crystal and organic composition in humans, by comparing samples taken from patients who had a hip fracture (HF) and individuals with hip osteoarthritis (HOA). METHODS: The study included 31 HF patients and 42 cases of HOA who underwent joint replacement surgery between 1/1/2013 and 31/12/2013. Trabecular bone samples were collected from the femoral heads and analyzed using a dual-energy X-ray absorptiometry, micro-CT, and solid-state high-resolution magic-angle-spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. RESULTS: No differences in proton or phosphorus concentration were found between the two groups using 1H single pulse, 31P single pulse, 31P single pulse with proton decoupling NMR spectroscopy, in hydroxyapatite (HA) c-axis or a-axis crystal length. Bone volume fraction (BV/TV), trabecular number (Tb.N), and bone mineral density (BMD) were higher in the HO group than in the HF group [28.6% ± 10.5 vs 20.3% ± 6.6 (p = 0.026); 2.58 mm-1 ± 1.57 vs 1.5 mm-1 ± 0.79 (p = 0.005); and 0.39 g/cm2 ± 0.10 vs. 0.28 g/cm2 ± 0.05 (p = 0.002), respectively]. The trabecular separation (Tp.Sp) was lower in the HO group 0.42 mm ± 0.23 compared with the HF group 0.58 mm ± 0.27 (p = 0.036). In the HO group, BMD was correlated with BV/TV (r = 0.704, p < 0.001), BMC (r = 0.853, p < 0.001), Tb.N (r = 0.653, p < 0.001), Tb.Sp (-0.561, p < 0.001) and 1H concentration (-0.580, p < 0.001) in the HO group. BMD was not correlated with BV/TV, Tb.Sp, Tb.Th, Tb.N, Tb.PF, 1H concentration or HA crystal size in the HF group. CONCLUSIONS: Patients with HO who did not sustain previous hip fractures had a higher femoral head BMD, BV/TV, and Tb.N than HF patients. In HO patients, BMD was positively correlated with the BV/TV and Tb.N and negatively correlated with the femoral head organic content and trabecular separation. Interestingly, these correlations were not found in HF patients with relatively lower bone densities. Therefore, osteoporotic patients with similar low bone densities could have significant microstructural differences. No differences were found between the two groups at a HA crystal level.

Altered topological blueprint of trabecular bone associates with skeletal pathology in humans.

Bone is a hierarchically organized biological material, and its strength is usually attributed to overt factors such as mass, density, and composition. Here we investigate a covert factor - the topological blueprint, or the network organization pattern of trabecular bone. This generally conserved metric of an edge-and-node simplified presentation of trabecular bone relates to the average coordination/valence of nodes and the equiangular 3D offset of trabeculae emanating from these nodes. We compare the topological blueprint of trabecular bone in presumably normal, fractured osteoporotic, and osteoarthritic samples (all from human femoral head, cross-sectional study). We show that bone topology is altered similarly in both fragility fracture and in joint degeneration. Decoupled from the morphological descriptors, the topological blueprint subjected to simulated loading associates with an abnormal distribution of strain, local stress concentrations and lower resistance to the standardized load in pathological samples, in comparison with normal samples. These topological effects show no correlation with classic morphological descriptors of trabecular bone. The negative effect of the altered topological blueprint may, or may not, be partly compensated for by the morphological parameters. Thus, naturally occurring optimization of trabecular topology, or a lack thereof in skeletal disease, might be an additional, previously unaccounted for, contributor to the biomechanical performance of bone, and might be considered as a factor in the life-long pathophysiological trajectory of common bone ailments.