OBJECTIVE: To investigate the impact of bone mass and volume of low-density zones beneath the tibial plateau on the maximum von Mises stresses experienced by the cartilage and meniscus in the knee joint. METHODS: The study included one healthy adult volunteer, from whom CT scans were obtained, and one patient diagnosed with knee osteoarthrisis (KOA), for whom X-ray films were acquired. A static model of the knee joint featuring a low-density zone was established based on a normal knee model. In the finite element analysis, axial loads of 1 000 N and 1 800 N were applied to the weight-bearing region of the upper surface of the femoral head for model validation and subsequent finite element studies, respectively. The maximum von Mises stresses in the femoral cartilage, as well as the medial and lateral tibial cartilage and menisci, were observed, and the stress percentage of the medial and lateral components were concurrently analyzed. Additionally, HE staining, as well as alkaline magenta staining, were performed on the pathological specimens of patients with KOA in various low-density regions. RESULTS: The results of model validation indicated that the model was consistent with normal anatomical structures and correlated with previous calculations documented in the literature. Static analysis revealed that the maximum von Mises stress in the medial component of the normal knee was the lowest and increased with the advancement of the hypointensity zone. In contrast, the lateral component exhibited an opposing trend, with the maximum von Mises stress in the lateral component being the highest and decreasing as the hypointensity zone progressed. Additionally, the medial component experienced an increasing proportion of stress within the overall knee joint. HE staining demonstrated that the chondrocyte layer progressively deteriorated and may even disappear as the hypointensity zone expanded. Furthermore, alkaline magenta staining indicated that the severity of microfractures in the trabecular bone increased concurrently with the expansion of the hypointensity zone. CONCLUSION The presence of subtalar plateau low-density zone may aggravate joint degeneration. In clinical practice, it is necessary to pay attention to the changes in the subtalar plateau low-density zone and actively take effective measures to strengthen the bone status of the subtalar plateau low-density zone and restore the complete biomechanical function of the knee joint, in order to slow down or reverse the progression of osteoarthritis.
Humans ; Finite Element Analysis ; Knee Joint/physiology* ; Tibia/anatomy & histology* ; Cartilage, Articular/physiology* ; Menisci, Tibial/physiopathology* ; Tomography, X-Ray Computed ; Osteoarthritis, Knee/diagnostic imaging* ; Weight-Bearing ; Bone Density ; Adult ; Stress, Mechanical ; Male ; Middle Aged ; Biomechanical Phenomena ; Female

OBJECTIVE: To explore the anatomical parameters of the cervical uncinate process "inflection point" through cervical CT angiography (CTA) and MRI measurements, offering a reliable and safe anatomical landmark for anterior cervical decompression surgery. METHODS: A retrospective analysis was conducted on the cervical CTA and MRI imaging data of normal adults who met the selection criteria between January 2020 and January 2024. The CTA dataset included 326 cases, with 200 males and 126 females, aged 22-55 years (mean, 46.7 years). The MRI dataset included 300 cases, with 200 males and 100 females, aged 18-55 years (mean, 43.7 years). Based on the CTA data, three-dimensional models of C ₃-C ₇ were constructed, and the following measurements were obtained from the superior view: uncinate process "inflection point" to vertebral artery distance (UIVD), uncinate process tip to vertebral artery distance (UTVD), uncinate process "inflection point" to "inflection point" distance (UID), uncinate process long-axis to sagittal angle (ULSA), and uncinate process "inflection point" to transverse foramen-sagittal angle (UITSA). From the anterior view, the anterior uncinate process to sagittal angle (AUSA) was measured. From the posterior view, the posterior uncinate process to sagittal angle (PUSA) was measured. Based on the MRI data, uncinate process "inflection point" to dural sac distance (UIDD) and dural sac width (DSW) were measured. The trends in measurement parameters of C ₃-C ₇ were observed, and the differences in measurement parameters between genders and between the left and right sides of the same segment were compared, as well as the difference in UID and DSW within the same segment was compared. RESULTS: The measurement parameters from C ₃ to C ₇ in the CTA data showed a general increasing trend, with no significant difference between the left and right sides within the same segment ( P>0.05). The UIVD, UTVD, and UID were greater in males than in females, with significant differences observed in the UIVD and UTVD at C ₃ and C ₆ and UID at C ₃, C ₆, and C ₇ ( P<0.05). The MRI measured DSW showed a general increasing trend from C ₃ to C ₇, and the DSW at C ₆ was greater in females than in males, with a significant difference ( P<0.05). The UIDD showed a gradual decreasing trend, with the smallest value at C ₆. There was no significant difference between males and females or between the left and right sides within the same segment ( P>0.05). The UID was greater than the DSW at C ₃-C ₇, and the differences were significant ( P<0.05). CONCLUSION The uncinate process "inflection point" is a constant anatomical structure located at the anteromedial aspect of the uncinate process tip and laterally to the dural sac. It maintains a certain safe distance from the vertebral artery. As a decompression landmark in anterior cervical spine surgery, it not only ensures surgical safety but also guarantees complete decompression.
Humans ; Adult ; Male ; Female ; Middle Aged ; Retrospective Studies ; Cervical Vertebrae/surgery* ; Magnetic Resonance Imaging ; Decompression, Surgical/methods* ; Young Adult ; Adolescent ; Computed Tomography Angiography ; Imaging, Three-Dimensional ; Vertebral Artery/anatomy & histology* ; Anatomic Landmarks/diagnostic imaging*

OBJECTIVE: To explore the morphological characteristics of the postero-superior protuberance of the calcaneus and to explore its relationship with Haglund malformation. METHODS: Ankle lateral X-ray films of 391 hospitalized patients between May 2021 and June 2024 were retrospectively collected. The morphological parameters of the postero-superior protuberance of the calcaneus were measured, including the length of the base, the height of the base, and the tip angle of the postero-superior protuberance of the calcaneus, and the morphological types were classified according to the above parameters, including the peak type, the hill type, and the flat type. The related parameters of Haglund malformation were measured, including Fowler-Philipp angle (FPA), calcaneal pitch angle (CPA), parallel pitch line (PPL), Chauveaux-Liet angle (CLA), and X/Y ratio (total calcaneal length/length of greater tuberosity of calcaneus). The differences of the morphological parameters of the postero-superior protuberance of the calcaneus and the related indicators of Haglund deformity among the three types and between the males and the females were compared and analyzed, and the differences of the positive numbers of the related indicators of Haglund deformity among the three types were compared. RESULTS: According to the morphological parameters of the postero-superior protuberance of the calcaneus, there were 64 cases of peak type, 245 cases of hill type, and 82 cases of flat type. There was no significant difference in the length of the base of the postero-superior protuberance of the calcaneus, CPA, CLA, and X/Y ratio among the three types ( P>0.05). Among the three types, the peak type had the largest FPA and the flat type had the smallest ( P<0.05); the peak type had the smallest tip angle of the postero-superior protuberance of the calcaneus and the flat type had the largest ( P<0.05); the positive rate of PPL in the hill type was significantly higher than that in the peak type and flat type ( P<0.05); the height of the base of the postero-superior protuberance of the calcaneus in the flat type was the smallest ( P<0.05). FPA, CPA, CLA, PPL, and X/Y ratio were positive in 2, 42, 172, 142, and 77 patients, respectively. There was no significant difference in the number of positive Haglund deformity indicators among the three types ( P>0.05). There was no significant difference between male and female patients in the tip angle of the postero-superior protuberance of the calcaneus, FPA, the positive rate of PPL, and X/Y ratio ( P>0.05). The length and the height of the base of the postero-superior protuberance of the calcaneus, CPA, and CLA in male patients were significantly higher than those in female patients ( P<0.05). CONCLUSION The postero-superior protuberance of the calcaneus can be divided into three types: the peak type, the hill type, and the flat type. The peak type is more likely to suffer from Haglund deformity, and the males are more likely to suffer from Haglund deformity than the females.
Humans ; Calcaneus/anatomy & histology* ; Male ; Female ; Retrospective Studies ; Adult ; Middle Aged ; Adolescent ; Young Adult ; Radiography ; Child ; Aged

OBJECTIVE: To conduct a comprehensive analysis of proximal humeral anatomical characteristics in the Chinese population utilizing three-dimensional reconstruction technology, thereby establishing an evidence base for the enhancement of shoulder hemiarthroplasty procedures and the development of domestically manufactured prostheses. METHODS: The study cohort comprised 30 patients (60 shoulders) presenting with cervicoscapular pain between July 2023 and June 2025, with equal gender distribution (15 males and 15 females); age distribution ranged from 20 to 75 years (mean, 53.7 years). Data acquisition was performed via high-resolution CT imaging (technical parameters: slice thickness 0.625 mm, voltage 120 kV, current 150 mA, matrix 512×512). Subsequently, CT datasets were processed in DICOM format using Mimics17.0 software for three-dimensional reconstruction, followed by quantitative assessment via Imageware12.0 software to evaluate key proximal humeral parameters: humeral head dimensions (coronal diameter, sagittal diameter, surface curvature diameter, thickness), angular measurements [neck-shaft angle, retroversion angle (retroversion angle 1 was the angle between the humeral head axis and the line connecting the medial and lateral condyles, and retroversion angle 2 was the angle between the humeral head axis and the tangent of the trochlea)], and positional metrics (medial offset, posterior offset). Statistical analysis incorporated Pearson correlation coefficients to determine parameter relationships, with comparative evaluations conducted across demographic variables including gender, height, body mass, and age. RESULTS: Quantitative analysis yielded the following measurements: humeral head coronal diameter (41.8±3.6) mm, sagittal diameter (39.1±4.1) mm, surface curvature diameter (44.9±4.6) mm, thickness (17.2±1.8) mm, neck-shaft angle (128.4±4.2)°, retroversion angle 1 (16.9±8.9)°, retroversion angle 2 (21.4±11.3)°, medial offset (3.8±1.7) mm, and posterior offset (5.1±1.6) mm. Correlation analysis demonstrated the most pronounced positive relationship between humeral head surface curvature diameter and thickness ( r=0.966, P=0.001), with additional significant positive correlations observed between surface curvature diameter and coronal diameter ( r=0.842, P=0.001), posterior offset and retroversion angle 1 ( r=0.766, P=0.001), and coronal diameter and thickness ( r=0.727, P=0.001). Demographic analysis revealed significantly greater dimensions in males compared to females for humeral head surface curvature diameter, coronal diameter, sagittal diameter, and thickness ( P<0.05), with these parameters demonstrating progressive increases corresponding to height ( P<0.05). With the exception of neck-shaft angle, all parameters exhibited a positive correlation with body mass. No significant age-related differences were detected across parameters ( P>0.05). CONCLUSION The proximal humeral morphology in the Chinese population exhibits substantial variability, necessitating optimization of prosthetic designs based on population-specific anatomical metrics to enhance the efficacy of personalized clinical interventions.
Humans ; Middle Aged ; Male ; Female ; Aged ; Imaging, Three-Dimensional/methods* ; Adult ; Tomography, X-Ray Computed/methods* ; Humerus/diagnostic imaging* ; Shoulder Joint/surgery* ; Hemiarthroplasty/methods* ; Humeral Head/anatomy & histology* ; Young Adult ; Clinical Relevance

OBJECTIVE: To investigate the anthropometric parameters that can accurately predict the diameter of the hamstring tendon graft, and to examine the correlation between disease etiology, duration, and graft diameter. METHODS: A retrospective analysis was conducted on data from 166 patients who underwent anterior cruciate ligament reconstruction using hamstring tendon autografts (semitendinosus and gracilis tendon) between January 2013 and December 2023. The cohort conprised 135 males and 31 females;the age ranged from 14 to 62 years old with an average of (28.87±10.46) years old. Pearson correlation coefficients, partial correlation coefficients, and stepwise multiple linear regression analysis were utilized to elucidate the relationship between the outcome variable (diameter of hamstring tendon grafts) and predictive variables (e.g., height). RESULTS: Correlation analysis revealed significant associations between the diameter of hamstring tendon grafts and height (r=0.379, P<0.001), weight (r=0.225, P=0.002), male gender (r=0.302, P<0.001), age(r=-0.218, P=0.002), and sports injury etiology (r=0.167, P=0.016). No significant correlations were found with surgical side, body mass index (BMI), or injury duration (P>0.05). Stepwise multiple linear regression analysis using a backward elimination method indicated that height was the sole significant predictive variable (R²=0.144, P<0.001), with the optimal predictive equation being:Graft size =2.636+0.029×Height (cm). Partial correlation analysis, after controlling for height, showed no significant association between age, gender, weight, and injury etiology with graft diameter. CONCLUSION Height is an effective predictive factor for the diameter of autologous hamstring tendon grafts. Factors such as gender, age, surgical side, body weight, and BMI are not influential to the diameter of the hamstring tendon grafts. Under the condition of the same height, there is no significant difference in the influence of these factors on the graft diameter. Preoperative physical activity level and the duration of injury do not significantly affect the diameter of the hamstring tendon grafts obtained during surgery. It is recommended to use the formula 'Graft Diameter=2.636 + 0.029 × Height (cm)' for preoperative prediction.
Humans ; Male ; Female ; Adult ; Middle Aged ; Retrospective Studies ; Adolescent ; Young Adult ; Transplantation, Autologous ; Anthropometry ; Anterior Cruciate Ligament Reconstruction ; Tendons/anatomy & histology* ; Autografts ; Hamstring Tendons/transplantation* ; Quadriceps Muscle/surgery*

PURPOSE: In surgical procedures commonly employed for the management of scaphoid and distal radial fractures, the incision and dissection of the pronator quadratus muscle play a pivotal role. Nevertheless, comprehensive investigations into the anatomical intricacies of the pronator quadratus muscle have been relatively scarce within the clinical community. In light of this, our study endeavors to make a substantive contribution to the medical literature by conducting a meticulous examination of the morphology and morphometry of this muscle. METHODS: This study is a cross-sectional observational study conducted on 22 cadaveric upper extremities (44 sides) preserved between January 2005 and December 2018 at Istanbul University. The study included specimens with intact dissection areas and no prior surgical intervention. Observations focused on the morphometry of the pronator quadratus muscle and related anatomical structures. Statistical analysis was performed using SPSS v23.0, employing Student's t-test and paired t-test, with significance set at p < 0.05. RESULTS: Significant differences were found in the morphometric measurements of the pronator quadratus muscle between the right and left upper extremities, particularly in the vertical distance between the proximal and distal attachment points of the pronator quadratus to the radius (p = 0.008). Additionally, significant differences were observed between male and female samples for radius length (p < 0.001), ulna length (p < 0.001), pronator quadratus width (p < 0.001), and the vertical distance between pronator quadratus attachment points on both the radius (p = 0.001) and ulna (p = 0.001). Furthermore, significant correlations were identified between radius length and parameters such as the vertical distance between pronator quadratus attachment points on both the radius (p = 0.002) and pronator quadratus width (p = 0.030), and between ulna length and parameters including the vertical distances on the radius (p = 0.001) and ulna (p = 0.024). CONCLUSION In light of our comprehensive analysis, which encompasses not only the anatomical features of the pronator quadratus muscle but also its vascular supply and the organization of its neurovascular structures, we posit that our study holds significant implications for the field of orthopedic surgery. We anticipate that this research will furnish valuable insights that can inform and enhance orthopedic procedures.
Humans ; Female ; Male ; Cross-Sectional Studies ; Muscle, Skeletal/anatomy & histology* ; Cadaver ; Aged ; Middle Aged

PURPOSE: End-stage knee osteoarthritis (OA) patients are the primary candidates for total knee arthroplasty (TKA). However, most morphological refinements of TKA prosthesis are based on anatomical data from the knees of healthy individuals. This study aimed to determine whether differences exist in key bony morphological characteristics of the distal femur and proximal tibia between osteoarthritic knees and healthy knees. METHODS: This was a retrospective cross-sectional observational study with a case-control design. Patients who were aged ≥ 50 years, had no history of trauma, fracture, or surgery in the studied knee, and had no obvious knee flexion contracture were included in this study by CT scans. Patients who met the American College of Rheumatology clinical criteria for knee OA were included in the study group. Kellgren-Lawrence grade III or IV knees were studied (for bilateral cases, the more severely affected knee was chosen). Patients who presented with unilateral knee pain or trauma were included in the control group, with CT scans from the opposite (asymptomatic) knee used for analyzing. The studied knee had a Kellgren-Lawrence grade of 0 or I and showed no abnormalities upon physical examination. Archived knee CT scans from 160 patients were divided into 2 groups: the study group (80 moderate-to-severe OA knees) and the control group (80 healthy knees). After 3-dimensional reconstruction and virtual cutting using a CT workstation, 13 morphological parameters of the distal femur and proximal tibia were compared between the 2 groups using independent-samples t-tests. RESULTS: No significant group differences in the femoral anteroposterior dimension (p = 0.797), height of the lateral femoral condyle (p = 0.268), posterior condylar angle (p = 0.240), tibial anteroposterior dimension (p = 0.536), or tibial lateral anteroposterior dimension (p = 0.702) were observed. However, the femoral mediolateral dimension (p = 0.002), distal femoral aspect ratio (femoral mediolateral dimension/femoral anteroposterior dimension) (p < 0.001), height of the femoral trochlear groove (p < 0.001), height of the medial femoral condyle (p < 0.001), tibial mediolateral dimension (p = 0.001), proximal tibial aspect ratio (tibial mediolateral dimension/tibial anteroposterior dimension) (p = 0.004), tibial medial anteroposterior dimension (p = 0.005), and tibial asymmetry ratio (tibial medial anteroposterior dimension/tibial lateral anteroposterior dimension) (p = 0.006) were all significantly greater in the study group. CONCLUSION Knees with moderate-to-severe OA are significantly wider than healthy knees, and OA is a risk factor for increased tibial platform asymmetry. When refining the morphological parameters of TKA prostheses, the specific bony morphological characteristics of OA knees should be taken into account to reduce the potential risk of femoral or tibial component underhang and facilitate optimal balance between tibial component fit and rotational alignment.
Humans ; Osteoarthritis, Knee/pathology* ; Male ; Female ; Cross-Sectional Studies ; Retrospective Studies ; Arthroplasty, Replacement, Knee ; Middle Aged ; Aged ; Case-Control Studies ; Prosthesis Design ; Knee Prosthesis ; Femur/anatomy & histology* ; Tibia/anatomy & histology* ; Tomography, X-Ray Computed ; Knee Joint/diagnostic imaging*

BACKGROUND: The protective effectiveness of an N95 respirator depends on the filtration efficiency of the material from which the N95 respirator is made of, as well as the wearers' facial fit. The facial fit of an N95 respirator mainly depends on the degree of matching between the wearers' facial dimension characteristics and the N95 respirator. Quantitative fit testing objectively evaluates the fit of N95 respirators; however, it is not easy to promote because of the limitations of testing conditions. The aim of this study is to establish a fit prediction model of N95 respirator based on facial images. METHODS: Facial images and fit factor (FF) value of 5 N95 respirators were gathered from 299 medical staffs in 10 hospitals in Beijing. Face geometry measurement was based on 3D face modelling, and the American TSI-8038 Porta Count Pro+ was used to conduct quantitative fit test. Multiple linear regression analysis was employed to identify facial dimensional features that significantly influenced the fit of N95 respirators. Through matching training of facial image and FF values, a fit prediction model has been established, enabling rapid recommendation of N95 respirators meeting the fit standard via facial image recognition. RESULTS: A fit prediction model for N95 respirators based on facial images has been developed, which enables the rapid recommendation of N95 respirators with acceptable FF value for healthcare personnel. The model demonstrated an accuracy of 55.93%, a precision of 98.43%, a recall of 51.65%, and an F1 score of 0.68. CONCLUSIONS It is feasible to utilize computer-based facial recognition technology to rapidly recommend N95 respirators for medical personnel. Given the high level of accuracy achieved, the model demonstrates significant potential for practical application.
Humans ; Face/anatomy & histology* ; N95 Respirators/standards* ; Male ; Adult ; Female ; Middle Aged ; Beijing

OBJECTIVE: To compare the registration accuracy of cone beam computed tomography (CBCT) images while registering to virtual craniodentofacial patients based on soft tissue and the dentition registration method. METHODS: Virtual dentofacial patients out of 13 selected participants who needed CBCT scanning were established by impression with a registered-block impression (RBI) based on digital dental images, three-dimensional (3D) facial images and maxillofacial CBCT images. CBCT images were processed in the Mimics software program, establishing the craniofacial virtual patients based on CBCT images (CCTs). Registration between virtual patients from RBI and CCT, using the soft tissue in lower half face (STE) and dentition (DTN) as the reference area, respectively, forming two kinds of virtual craniofacial patients based on digital dental images, 3D facial images and skeletal images of CBCT (hiding the soft tissue and dental casts from CBCT). Three-dimensional deviation analysis was performed in the upper half face and lower half face of facial images from CBCT between two kinds of virtual craniodentofacial patients and compared with 3D facial images from RBI and recorded as root mean square error (RMSE). Paired-t test was used to compare the deviations of RMSEs between the upper and lower half of the face and the upper half of the face of facial images from CCT, respectively, between the two kinds of virtual craniodentofacial patients based on STE and DTN methods. RESULTS: Paired-t tests showed that there was no statistically significant difference between the upper and lower half faces of facial images from CCT between STE and DTN (P>0.05), but the deviation of RMSEs of the upper half face of facial images from CCT in STE was smaller than those in DTN [(1.696±0.420) mm vs. (1.752±0.424) mm, P < 0.01]. CONCLUSION The registration accuracy of CBCT registered in virtual craniodentofacial patients using soft tissue as the reference area was higher.
Humans ; Cone-Beam Computed Tomography/methods* ; Imaging, Three-Dimensional/methods* ; Male ; Face/anatomy & histology* ; Female ; Adult ; Image Processing, Computer-Assisted/methods* ; Young Adult ; User-Computer Interface

OBJECTIVE: To investigate the changes and symmetry of facial soft tissue during posed smile, to analyze the feature of posed smile in different gender, and verify the reproducibility of posed smile. METHODS: Three-dimensional (3D) facial images of 41 adults (16 males and 25 females with an average age of 26.76±2.70 years) which were taken by FaceScan three-dimensional sensor, including one rest position and two posed smile images. Then these images were imported into 3D soft tissue analysis software for model repositioning. 3D morphable model method (3DMM) was carried out to automatic landmarks setting. After that, the measurement of the eyes, cheeks, nose and perioral area were carried out for 3D soft tissue analysis. Finally, the changes and symmetry of the soft tissues between the two expression states and the gender differences during the posed smiles were compared. Meanwhile, the reproducibility of posed smile was statistically tested. RESULTS: Compared with the rest position, except for nasolabial angle (1.45°±7.65°), the measurements of 3D soft tissue in other region were changed in posed smile (P < 0.001). It should be noted that the eye region was also significantly changed (P < 0.001). Furthermore, the prominent feature of posed smile was that the alar base length became longer, the upper and lower vermilions were narrow and thin, and the mentolabial furrows became shallow. Meanwhile the chin extended anteriorly while the mouth retracted; During posed smile, the labial fissure asymmetry [2.78 (1.73, 3.49) mm], mid-infraorbital asymmetry [2.36 (1.22, 3.27) mm] and outercanthal asymmetry [2.31(1.29, 2.80) mm] were most apparent. Compared with the rest position, the asymmetry was not significantly increased except for cheilion and alar curvature points during the posed smile (P>0.05). In the posed smile, the changes of the right palpebral fissure height and the thickness of lower vermilion (|Li-Stoi| _z) of males were greater than those of females (P < 0.05), and asymmetry of exocanthion and cheekbone increased more than that of females (P < 0.05). There was no obvious difference between the two posed smiles. CONCLUSION In this study, during the posed smile the soft tissues of the eyes, cheeks, nose, lips and chin changed in different degrees, and the asymmetry of cheilion and alar curvature point was greater than that of the rest position; In addition, the reproducibility of posed smile was excellent, which can be a reference for clinical aesthetics and functional research of smile.
Humans ; Smiling/physiology* ; Female ; Male ; Adult ; Imaging, Three-Dimensional/methods* ; Face/anatomy & histology* ; Young Adult ; Facial Expression