BACKGROUND: This study aims to investigate the impact of varying coronal alignments of femoral prostheses on stress and strain distributions within the lateral compartment following unicompartmental knee arthroplasty (UKA) in patients with normal bone density and osteoporosis using finite element analysis. Additionally, it examines the relationship between osteoporosis and the progression of osteoarthritis in the lateral compartment postoperatively.
METHODS: UKA models were developed for both normal bone and osteoporotic conditions using a validated finite element model of the knee. Seven alignment conditions for the femoral prosthesis were simulated: 0° (neutral alignment), varus angles of 3°, 6°, and 9°, and valgus angles of 3°, 6°, and 9°, resulting in a total of 14 scenarios. Stress and strain distributions in the meniscus, tibial cartilage, and femoral cartilage of the lateral compartment were evaluated.
RESULTS: The results indicated that stress and strain in the meniscus, tibial cartilage, and femoral cartilage of the lateral compartment increased with greater varus alignment and decreased with greater valgus alignment in both normal and osteoporotic models. At equivalent alignment angles, stress and strain were consistently higher in the osteoporotic model (M2) compared to the normal bone model (M1), although the peak equivalent stress in the tibial cartilage was lower in the M2 model than in the M1 model.
CONCLUSIONS: In patients with osteoporosis undergoing fixed-bearing medial UKA, varus malalignment of the femoral prosthesis can lead to increased stress and strain in the lateral compartment\'s meniscus, tibial cartilage, and femoral cartilage. These findings suggest that osteoporosis may contribute to abnormal stress and strain distributions in the lateral compartment following UKA, potentially accelerating the progression of osteoarthritis in this region postoperatively.

BACKGROUND: Ongoing lower extremity long-bone nonunion is a devastating condition and associated with substantial patient morbidity. There is limited evidence regarding physical and mental function after surgical management of lower extremity nonunions. The purpose of this study was to assess general physical and mental health and lower extremity specific physical function of patients that underwent surgery for a lower extremity long-bone nonunion.
METHODS: One-hundred and twenty-four adult patients who underwent successful surgical management for a lower extremity long-bone nonunion between June 2002 and December 2021 were evaluated at an average follow-up of 8.6 years (interquartile range [IQR]: 4 - 12). General physical and mental health was assessed with the Short-Form 12 (SF-12) physical (PCS) and mental (MCS) component summaries, and lower extremity specific physical function with the Lower Extremity Functional Scale (LEFS). Multivariable linear regression was performed to identify variables that were independently associated with outcomes.
RESULTS: The median LEFS was 50 (IQR: 37 - 63) and the median SF-12 PCS was 43 (IQR: 33 - 52), which are both lower than normative population scores (LEFS: 77 and PCS: 51, p < 0.0001). The median SF-12 MCS was 50, which was comparable to the normative population score of 51 (p < 0.0001). The number of previous surgeries before the index nonunion treatment (p = 0.018 and p = 0.041) and the number of revision surgeries after the index nonunion treatment (p = 0.022 and p = 0.041) were associated with lower LEFS and SF-12 PCS scores.
CONCLUSIONS: At an average of 8.6 years after lower extremity nonunion surgery that led to bone healing, patients continue to report lower general and lower extremity specific physical functioning compared to the normative population. The number of surgical attempts to obtain definitive healing was associated with compromised physical function scores. Mental health scores may return close to normative population scores. These results can be used to inform patients and guide treatment strategies and healthcare policies.

It\'s imperative to create a more ideal biological scaffold for bone defect repair. Calcium phosphate bone cements (CPC) could be used as a scaffold. Some ingredients and osteogenic factors could be added to improve its poor mechanical properties and biological activity. As a macromolecule extracted from traditional Chinese medicine, Hedysarum polysaccharides (HPS) would significantly promote the osteogenic activity of bone biomaterials. Zirconium oxide and starch were added to the solid phase and citric acid was added to the liquid phase to optimize CPC. HPS was loaded onto the scaffold as an osteogenic factor, and the prepared CPS + HPS was characterized. Further, the cytocompatibility of CPS + HPS was assessed according to activity, differentiation, and calcification in neonatal rat calvarial osteoblasts, and the biosafety of CPS + HPS was evaluated according to acute toxicity, pyrogen, sensitization, and hemolysis. The success of CPS + HPS in repairing bone defects was evaluated by using a rabbit femur implantation experiment. After optimization, CPS-20-CA-5 containing 10% starch and 5% citric acid displayed the highest mechanical strength of 28.96 ± 0.03 MPa. HPS-50 was demonstrated to exert the best osteogenic effect. The combination of CPS + HPS achieved HPS-loaded CPC. Material characterization, cytocompatibility, biosafety, and femoral implantation experiments indicated that CPS + HPS possessed better pressure resistance and improved osteogenic ability in bone defect repair.CPS + HPS demonstrated effective pressure resistance and superior osteogenic ability, which may be of great significance for bone defects and bone tissue engineering to promote bone regeneration and repair.

Drug use during pregnancy is an important issue that must be investigated due to its adverse effects on maternal and foetal health. This study aimed to determine the embryotoxic and teratogenic effects of in-ovo administered metamizole (dipyrone), which can be used when needed during pregnancy and has potent analgesic, antipyretic, anti-inflammatory, and long bone (tibia and femur) effects. This study used 240 fertile eggs from Atak S breed chickens, divided into eight equal groups: control, vehicle control, and 15.62, 31.25, 62.5, 125, 250 and 500 mg/kg metamizole. The eggs were hatched on the 21st day of incubation, and the chicks\' body weights and mortality rates were determined. The right and left femur and tibia bones were resected from the chicks. Anatomical reference points were determined after removing the soft tissues of the bones, and necessary morphometric measures were taken from these points with a 0.01 mm precision using digital callipers. The 100% lethal dose (LD100) was identified in the highest examined dose (500 mg/kg) in the Chicken Embryotoxicity Screening Test (CHEST)-I stage. The CHEST-II stage determined the 50% lethal dose (LD50). High-dose metamizole affected skeletal development, significantly decreasing tibia and femur lengths and corpus thicknesses and increasing mortality.

Vitamin A derivatives have inhibitory effects on cartilage tissue, such as decreasing chondrocyte proliferation and collagen synthesis, and increasing the loss of glycosaminoglycans and proteoglycans. Therefore, isotretinoin (a vitamin A derivative) may play a role in the pathogenesis of cartilage-related diseases like osteoarthritis by affecting the balance of cartilage tissue. The aim of this study was to evaluate the distal femoral cartilage thickness in acne patients under the systemic isotretinoin therapy and to determine whether it constitutes a risk factor for the development of osteoarthritis. The study included 52 patients (42 female, 10 male, mean age 23.31 ± 3.89 years) who were prescribed systemic isotretinoin for acne and completed at least 3 months of treatment, along with 45 healthy controls ((35 female, 10 male, mean age 23.85 ± 4.77 years). Bilateral distal femoral cartilage thickness was measured by ultrasonography before isotretinoin treatment and after the completion of the third month of treatment. After treatment, a statistically significant increase was found in the thickness of the right medial, right lateral, left medial, left lateral, and left intercondylar cartilage (p = 0.014, 0.012, 0.019, 0.027, 0.002, respectively). There was also an increase in the right intercondylar cartilage thickness, but this was not statistically significant (p = 0.1). Systemic isotretinoin seems to make cartilage thicker. The increase in femoral cartilage thickness observed after short-term isotretinoin treatment might be an indicator of very early-stage osteoarthritis. Extended follow-up studies with larger participant pools are necessary to substantiate this result.

Nutrient foramina are small openings in the periosteal surface of the mid-shaft region of long bones that traverse the cortical layer and reach the medullary cavity. They are important for the delivery of nutrients and oxygen to bone tissue and are crucial for the repair and remodeling of bones over time. The nutrient foramina in the femur\'s diaphysis are related to the energetic needs of the femur and have been shown to be related to the maximum metabolic rate (MMR) of taxa. Here, we investigate the relationship between nutrient foramen size and body mass as a proxy to the aerobic capacity of taxa in living and extinct xenarthrans, including living sloths, anteaters, and armadillos, as well as extinct xenarthrans such as glyptodonts, pampatheres, and ground sloths. Seventy femora were sampled, including 20 from extant taxa and 50 from extinct taxa. We obtained the blood flow rate (Q̇) based on foramina area and performed PGLS and phylogenetic ANCOVA in order to explore differences among mammalian groups. Our results show that, among mammals, taxa commonly associated with lower metabolism like living xenarthrans showed relatively smaller foramina, while the foramina of giant extinct xenarthrans like ground sloths and glyptodonts overlapped with non-xenarthran placentals. Consequently, Q̇ estimations indicated aerobic capacities comparable to other placental giant taxa like elephants or some ungulates. Furthermore, the estimation of the MMR for fossil giant taxa showed similar results, with almost all taxa showing high values except for those for which strong semi-arboreal or fossorial habits have been proposed. Moreover, the results are compatible with the diets predicted for extinct taxa, which indicate a strong consumption of grass similar to ungulates and in contrast to the folivorous or insectivorous diets of extant xenarthrans. The ancestral reconstruction of the MMR values indicated a lack of a common pattern for all xenarthrans, strongly supporting the occurrence of low metabolic rates in extant forms due to their particular dietary preferences and arboreal or fossorial habits. Our results highlight the importance of considering different evidence beyond the phylogenetic position of extinct taxa, especially when extinct forms are exceptionally different from their extant relatives. Future studies evaluating the energetic needs of giant extinct xenarthrans should not assume lower metabolic rates for these extinct animals based solely on their phylogenetic position and the observations on their extant relatives.

UNASSIGNED: T-score measurement via dual-energy X-ray absorptiometry (DXA) is the gold standard for assessing and classifying the bone mineral density status of patients as normal, osteopenic, or osteoporotic according to the World Health Organization criteria. However, the diagnostic accuracy may be affected by the skeletal site selected for DXA.
UNASSIGNED: Estimate the prevalence of femoral and lumbar BMD discordance in a community-based setting in Riyadh, Saudi Arabia.
UNASSIGNED: Cross-sectional.
UNASSIGNED: Polyclinics at a tertiary care center.
UNASSIGNED: This study included all patients aged ≥60 years who visited the Department of Family Medicine and underwent DXA screening between 2016 and 2022.
UNASSIGNED: Discordance was defined as a difference in BMD status between two skeletal sites. Minor discordance occurs when adjacent sites have different diagnoses; i.e., one site exhibits osteoporosis and the other exhibits osteopenia. In contrast, major discordance occurs when one site exhibits osteoporosis and the other exhibits normal BMD.
UNASSIGNED: 1429 older adults.
UNASSIGNED: The study patients had a median age of 66 years (60-99, minimum-maximum). The prevalence of discordance was 41.6%, with major discordance present in 2.2% of patients and minor discordance in 39.4%. The distribution of discordance did not differ significantly among the sociodemographic factors.
UNASSIGNED: Discordance is prevalent among the Saudi geriatric population. During the analysis of DXA results, physicians should account for discordance when diagnosing and ruling out osteoporosis in high-risk patients.
UNASSIGNED: All factors influencing discordance were not explored thoroughly; this study mainly focused on older adults. Furthermore, diverse age groups need to be investigated for a more comprehensive understanding of the analyzed factors.

OBJECTIVE: To evaluate outcomes and complication rate of utilizing a string-of-pearls (SOP) plate augmented with adjunctive fixation in the repair of canine femur fractures.
METHODS: Records of canine patients with mid-diaphyseal femoral fractures repaired with the SOP plate and adjunctive fixation were reviewed. Information retrieved from medical records included signalment, patient weight, fracture configuration, repair technique, healing time, and complications based on perioperative radiographic follow-up to clinical union. Forty client-owned dogs met inclusion criteria for this study. Variables analyzed for association with major complications included body weight, fracture configuration, repair technique, and adjunctive fixation.
RESULTS: Major complications requiring surgical revision occurred in 8 of 40 fractures. Five cases experienced intramedullary pin migration and were successfully treated with sedated pin removal. The remaining 3 cases involved implant failure via screw shear breakage and required surgical revision of the fixation to achieve a successful outcome. On the basis of a calculated Bonferroni correction, no statistical significance of the tested variables was found in association with major complications; however, significance was limited due to the low statistical power of this study.
CONCLUSIONS: The use of adjunctive fixation with the SOP locking plate system led to radiographic union without complication in most cases, and no instances of plate breakage were reported. However, implant complications secondary to the adjunctive fixation can occur.
CONCLUSIONS: Adjunctive fixation used with the SOP plate for repair of canine femur fractures has a high success rate, though pin migration as a complication persists.

BACKGROUND: Cementless fixation has become increasingly popular in hip arthroplasty due to its shorter operation time, easier technique, biologic fixation, and avoidance of bone cement implantation syndrome compared to cemented fixation. However, intraoperative periprosthetic femoral fracture (IOPFx) is a disconcerting complication during cementless hip arthroplasty. Our purpose was to identify the features of cementless stem that increase the risk of IOPFx during primary hip arthroplasty.
METHODS: We retrospectively reviewed all 4806 hip arthroplasties that was performed in a single institution from May 2003 to December 2020. Age at the index arthroplasty, sex, body mass index, physical status, ambulatory function, side of the operation, operational history, cause of the index arthroplasty, type of arthroplasty, surgical approach, surgeon, implant information, and events during the operation were investigated. The shoulder geometry and length of stem were also reviewed. The event of interest was narrowed down to IOPFx among various records of intraoperative events.
RESULTS: We found IOPFx of 2.6% among all the hips operated with cementless stem. In the multivariable analysis, female (OR = 1.52), childhood hip disease (OR = 2.30), stove-pipe femur (OR = 2.43), combined approach (OR = 2.60), and standard length of stem (OR = 1.59) were found to be significant risk factors of IOPFx.
CONCLUSIONS: In conclusion, a stem with a standard length is significantly associated with risk of IOPFx compared to a shortened stem. These findings highlight the importance of careful consideration in terms of the risk of IOPFx when standard length cementless stem is chosen.

BACKGROUND: Metastases increase the risk of fracture when affecting the femur. Consequently, clinicians need to know if the patient\'s femur can withstand the stress of daily activities. The current tools used in clinics are not sufficiently precise. A new method, the CT-scan-based finite element analysis, gives good predictive results. However, none of the existing models were tested for reproducibility. This is a critical issue to address in order to apply the technique on a large cohort around the world to help evaluate bone metastatic fracture risk in patients. The aim of this study is then to evaluate 1) the reproducibility 2) the transposition of the reproduced model to another dataset and 3) the global sensitivity of one of the most promising models of the literature (original model).
METHODS: The model was reproduced based on the paper describing it and discussion with authors to avoid reproduction errors. The reproducibility was evaluated by comparing the results given in the original model by the original first team (Leuven, Belgium) and the reproduced model made by another team (Lyon, France) on the same dataset of CT-scans of ex vivo femurs. The transposition of the model was evaluated by comparing the results of the reproduced model on two different datasets. The global sensitivity analysis was done by using the Morris method and evaluates the influence of the density calibration coefficient, the segmentation, the orientations and the length of the femur.
RESULTS: The original and reproduced models are highly correlated (r2 = 0.95), even though the reproduced model gives systematically higher failure loads. When using the reproduced model on another dataset, predictions are less accurate (r2 with the experimental failure load decreases, errors increase). The global sensitivity analysis showed high influence of the density calibration coefficient (mean variation of failure load of 84 %) and non-negligible influence of the segmentation, orientation and length of the femur (mean variation of failure load between 7 and 10 %).
CONCLUSIONS: This study showed that, although being validated, the reproduced model underperformed when using another dataset. The difference in performance depending on the dataset is commonly the cause of overfitting when creating the model. However, the dataset used in the original paper (Sas et al., 2020a) and the Leuven\'s dataset gave similar performance, which indicates a lesser probability for the overfitting cause. Also, the model is highly sensitive to density parameters and automation of measurement may minimize the uncertainty on failure load. An uncertainty propagation analysis would give the actual precision of such model and improve our understanding of its behavior and is part of future work.