Development and Validation of an Automated Classification System for Osteonecrosis of the Femoral Head Using Deep Learning Approach: A Multicenter Study.

BACKGROUND: Accurate classification can facilitate the selection of appropriate interventions to delay the progression of osteonecrosis of the femoral head (ONFH). This study aimed to perform the classification of ONFH through a deep learning approach. METHODS: We retrospectively sampled 1,806 midcoronal magnetic resonance images (MRIs) of 1,337 hips from 4 institutions. Of these, 1,472 midcoronal MRIs of 1,155 hips were divided into training, validation, and test datasets with a ratio of 7:1:2 to develop a convolutional neural network model (CNN). An additional 334 midcoronal MRIs of 182 hips were used to perform external validation. The predictive performance of the CNN and the review panel was also compared. RESULTS: A multiclass CNN model was successfully developed. In internal validation, the overall accuracy of the CNN for predicting the severity of ONFH based on the Japanese Investigation Committee classification was 87.8%. The macroaverage values of area under the curve (AUC), precision, recall, and F-value were 0.90, 84.8, 84.8, and 84.6%, respectively. In external validation, the overall accuracy of the CNN was 83.8%. The macroaverage values of area under the curve, precision, recall, and F-value were 0.87, 79.5, 80.5, and 79.9%, respectively. In a human-machine comparison study, the CNN outperformed or was comparable to that of the deputy chief orthopaedic surgeons. CONCLUSION: The CNN is feasible and robust for classifying ONFH and correctly locating the necrotic area. These findings suggest that classifying ONFH using deep learning with high accuracy and generalizability may aid in predicting femoral head collapse and clinical decision-making.

Comparison of Glenohumeral Bone Morphology Between Patients With Versus Without Anterior Shoulder Instability.

Background: The stability of the glenohumeral joint is associated with anatomic characteristics including bony structures and soft tissues. Purpose: To compare the differences in specific bony glenohumeral geometries between shoulders with anterior shoulder instability (ASI), unaffected contralateral shoulders, and healthy control shoulders. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Shoulder computed tomography (CT) scans of 36 patients with ASI and 36 matched healthy controls were retrieved and 3-dimensionally reconstructed. We measured the glenoid radius of curvature (GROC) in the anterior-posterior (AP) and superior-inferior directions, humeral head radius of curvature (HROC) in the AP direction, conformity index, glenoid height, glenoid width, glenoid index, stability angle, glenoid version, and glenoid depth. The differences between the groups were statistically calculated. CT scans of the unaffected contralateral shoulders from 21 of the ASI patients were also collected to identify the consistency of the bony structures in bilateral shoulders. Results: Patients with ASI had greater GROC in the AP direction (P < .001), HROC in the AP direction (P = .002), glenoid height (P = .005), and glenoid index (P < .001) and smaller conformity index (P < .001), glenoid width (P = .002), stability angle (P < .001), and glenoid depth (P < .001). In addition, the glenoid of the ASI patients was more anteverted compared with that of controls (P = .001). There was no statistical difference in half the measurements between the bilateral shoulder joints in patients with ASI. Conclusion: In this study, glenohumeral geometric differences were found between ASI patients and healthy control participants. Glenoid curvature and conformity index, based on bilateral comparisons of affected and contralateral shoulders, appear inherent and may predict ASI risk.

Automatic detection of early osteonecrosis of the femoral head from various hip pathologies using deep convolutional neural network: a multi-centre study.

PURPOSE: The aim of this study was to develop a deep convolutional neural network (DCNN) for detecting early osteonecrosis of the femoral head (ONFH) from various hip pathologies and evaluate the feasibility of its application. METHODS: We retrospectively reviewed and annotated hip magnetic resonance imaging (MRI) of ONFH patients from four participated institutions and constructed a multi-centre dataset to develop the DCNN system. The diagnostic performance of the DCNN in the internal and external test datasets was calculated, including area under the receiver operating characteristic curve (AUROC), accuracy, precision, recall, and F1 score, and gradient-weighted class activation mapping (Grad-CAM) technique was used to visualize its decision-making process. In addition, a human-machine comparison trial was performed. RESULTS: Overall, 11,730 hip MRI segments from 794 participants were used to develop and optimize the DCNN system. The AUROC, accuracy, and precision of the DCNN in internal test dataset were 0.97 (95% CI, 0.93-1.00), 96.6% (95% CI: 93.0-100%), and 97.6% (95% CI: 94.6-100%), and in external test dataset, they were 0.95 (95% CI, 0.91- 0.99), 95.2% (95% CI, 91.1-99.4%), and 95.7% (95% CI, 91.7-99.7%). Compared with attending orthopaedic surgeons, the DCNN showed superior diagnostic performance. The Grad-CAM demonstrated that the DCNN placed focus on the necrotic region. CONCLUSION: Compared with clinician-led diagnoses, the developed DCNN system is more accurate in diagnosing early ONFH, avoiding empirical dependence and inter-reader variability. Our findings support the integration of deep learning systems into real clinical settings to assist orthopaedic surgeons in diagnosing early ONFH.

Deep Learning Approach for Diagnosing Early Osteonecrosis of the Femoral Head Based on Magnetic Resonance Imaging.

BACKGROUND: The diagnosis of early osteonecrosis of the femoral head (ONFH) based on magnetic resonance imaging (MRI) is challenging due to variability in the surgeon's experience level. This study developed an MRI-based deep learning system to detect early ONFH and evaluated its feasibility in the clinic. METHODS: We retrospectively evaluated clinical MRIs of the hips that were performed in our institution from January 2019 to June 2022 and collected all MRIs diagnosed with early ONFH. An advanced convolutional neural network (CNN) was trained and optimized; then, the diagnostic performance of the CNN was evaluated according to its accuracy, sensitivity, and specificity. We also further compared the CNN's performance with that of orthopaedic surgeons. RESULTS: Overall, 11,061 images were retrospectively included in the present study and were divided into three datasets with ratio 7:2:1. The area under the receiver operating characteristic curve, accuracy, sensitivity, and specificity of the CNN model for identifying early ONFH were 0.98, 98.4, 97.6, and 98.6%, respectively. In our review panel, the averaged accuracy, sensitivity, and specificity for identifying ONFH were 91.7, 87.0, and 94.1% for attending orthopaedic surgeons; 87.1, 84.0, and 89.3% for resident orthopaedic surgeons; and 97.1, 96.0, and 97.9% for deputy chief orthopaedic surgeons, respectively. CONCLUSION: The deep learning system showed a comparable performance to that of deputy chief orthopaedic surgeons in identifying early ONFH. The success of deep learning diagnosis of ONFH might be conducive to assisting less-experienced surgeons, especially in large-scale medical imaging screening and community scenarios lacking consulting experts.

Optimal Timing of Anterior Cruciate Ligament Reconstruction in Patients With Anterior Cruciate Ligament Tear: A Systematic Review and Meta-analysis.

Importance: The timing of surgery has been regarded as a key factor in anterior cruciate ligament reconstruction (ACLR), and early vs delayed ACLR remains a controversial topic. Objective: To synthesize up-to-date published data from randomized clinical trials (RCTs) comparing early vs elective delayed ACLR for patients with ACL deficiency, in terms of clinical outcomes and complications. Data Sources: The PubMed, Cochrane Library, and Web of Science databases were systematically searched until September 9, 2022. Study Selection: All published RCTs comparing clinical and functional outcomes and complications associated with early ACLR vs elective delayed ACLR. Data Extraction and Synthesis: Two reviewers independently extracted relevant data and assessed the methodological quality following the PRISMA guidelines. Main Outcomes and Measures: Due to the clinical heterogeneity, the random-effects model was preferred. The primary outcomes were functional outcomes and complications. The Mantel-Haenszel test was used to evaluate dichotomous variables and the inverse variance method was used to assess continuous variables. Results: This meta-analysis included 972 participants in 11 RCTs stratified by follow-up duration. The following factors did not differ between early and delayed ACLR: operative time (mean difference, 4.97; 95% CI, -0.68 to 10.61; P = .08), retear (OR, 1.52; 95% CI, 0.52-4.43; P = .44), and infection (OR, 3.80; 95% CI, 0.77-18.79; P = .10). There were also no differences between groups in range of motion, knee laxity, International Knee Documentation Committee (IKDC rating scale), and Tegner score. IKDC score (mean difference, 2.77; 95% CI, 1.89-3.66; P < .001), and Lysholm score at 2-year follow-up (mean difference, 2.61; 95% CI, 0.74-4.48; P = .006) significantly differed between early and delayed ACLR. In addition, the timing of surgery was redefined in the included RCTs and subgroup analyses were performed, which validated the robustness of the principal results. Conclusion and Relevance: This systematic review and meta-analysis found that early ACLR was not superior to delayed ACLR in terms of most factors analyzed, except for IKDC and Lysholm scores. This information should be available to patients with ACL deficiency and clinicians as part of the shared decision-making process of treatment selection.

Acetabular Revision Arthroplasty Based on 3-Dimensional Reconstruction Technology Using Jumbo Cups.

Background: This study was aimed at evaluating the changes in cup coverage (CC) and hip center of rotation (HCOR) in acetabular defects of various severities treated with acetabular revision using jumbo cups. Methods: A total of 86 hips were included. The American Academy of Orthopedic Surgeons (AAOS) classification of these patients was as follows: 16 patients, AAOS I; 16 patients, AAOS II; and 16 patients, AAOS III. A three-dimensional (3D) implant simulation technique was used to visualize the placement of jumbo cups during revision arthroplasty. The acetabular anteversion, inclination, CC, and the HCOR were measured. Results: The inclination and anteversion of simulated acetabular cups in AAOS I-III groups were consistent with the normal acetabular anatomy. Compared with the controls, in AAOS I-III groups, the HCOR was significantly increased and CC was significantly decreased. The HCOR elevation was significantly higher in AAOS III patients than in AAOS I (p = 0.001) and AAOS II patients (p < 0.001). The use of the jumbo cup technology for acetabular revision would decrease the CC in AAOS I-III patients to 86.47, 84.78, and 74.51%, respectively. Conclusion: Our study demonstrated that in patients with acetabular defects, acetabular revision arthroplasty using jumbo cups will lead to decreased CC and HCOR upshift. Upon classifying these patients according to the AAOS classification, CC decreased with the severity of acetabular defects, and the elevation of the HCOR in AAOS III patients exceeded 10 mm and was significantly higher than in other patients.

Osteoradionecrosis of the Hip, a Troublesome Complication of Radiation Therapy: Case Series and Systematic Review.

Background: Osteoradionecrosis of the hip is a serious complication of radiotherapy that is easily overlooked by physicians and patients in the early stages. There are relatively few reports on this subject, so there is no clear scientific consensus for the pathogenesis, early diagnosis, and clinical treatment of hip osteoradionecrosis. In this paper, we report two cases of hip osteoradionecrosis and systematically review the related literature. Case Presentation: We report two cases of hip osteoradionecrosis. One patient successfully underwent total hip arthroplasty in our hospital and recovered well postoperatively. Another patient although we offered a variety of surgical options for this patient, the patient was worried that the bone loss would lead to poor prosthesis fixation, resulting in prosthesis loosening and infection, and therefore ultimately refused surgical treatment. Conclusion: With the development of radiological techniques, the incidence of hip osteoradionecrosis is decreasing year by year, but early diagnosis and rational treatment remain challenging. The effects of non-surgical treatment are limited. Early prevention, early detection, and early intervention are crucial to delay or prevent the emergence of more serious complications.

Trabecular metal versus non-trabecular metal acetabular components for acetabular revision surgery: A systematic review and meta-analysis.

BACKGROUND: The objective of this study was to compare cup survival and the incidence of adverse events associated with the use of trabecular metal (TM) and non-TM cups for acetabular revision surgery. METHODS: The MEDLINE, EMBASE, and Cochrane Library databases were searched for comparative studies that reported cup survival and the incidence of adverse events associated with the use of TM and non-TM cups for acetabular revision surgery. Primary outcomes included cup survival, aseptic loosening, dislocation, and infection. RESULTS: The meta-analysis included 6 studies that involved 13,864 total hip arthroplasty (THA) revisions who underwent acetabular revision surgery with TM (n = 5,619) or non-TM (n = 8,245) cups. The meta-analysis demonstrated no significant difference in cup survival using re-revision for any reason or aseptic loosening as the endpoint following acetabular revision surgery with TM or non-TM cups (HR = 0.96; [95% CI, 0.84-1.09]; HR = 1.29; [95% CI, 0.70-2.38]). Pooled data indicated that the overall incidence of adverse events for TM or non-TM cups was 6.8% (382/5,289) and 9.0% (725/8,083), respectively, and not significantly different (OR = 0.91; [95% CI, 0.80-1.04]). The incidence of aseptic loosening and infection were significantly lower (OR = 0.75; [95% CI, 0.58-0.96]; OR = 0.70; [95% CI, 0.54-0.90]) and the incidence of dislocation was significantly higher (OR = 1.53; [95% CI, 1.22-1.91]) for TM compared to non-TM cups. CONCLUSION: This review was the first to use reconstructed time-to-event data to find that there was no difference in survival of TM and non-TM cups in acetabular revision surgery. Overall, fewer adverse events were associated with the use of TM compared to non-TM cups, but the difference was not significant. The incidence of aseptic loosening and infection were significantly lower and the incidence of dislocation was significantly higher for TM compared to non-TM cups. This information is expected to guide orthopedic surgeons in the selection of appropriate acetabular components for THA revision.

Arthroscopic surgery for synovial chondroma of the subacromial bursa with non-traumatic shoulder subluxation complications: Two case reports.

BACKGROUND: Synovial chondromatosis is a disease originating from the synovium and characterized by the presence of metaplastic cartilaginous nodules in synovial cavities. The exact prevalence of synovial chondromatosis remains unknown, and the involvement of the shoulder joint is very rare. Synovial chondromatosis accompanied by subluxation of the humeral head without a history of trauma is rarely encountered, and to our knowledge, no published reports describe this condition. CASE SUMMARY: We present two cases of synovial chondromatosis in the shoulder joint, accompanied by subluxation of the humeral head, in two arthroscopically managed adult patients. We performed arthroscopic labrum fixation and removal of the loose body from the shoulder joint. To identify primary and secondary categories, pathological analysis was arranged. Clinical and radiographic evaluations at the 1-mo follow-up were satisfactory. CONCLUSION: The biomechanical function of the shoulder joint requires attention, especially following the detection of loose bodies, as observed with synovial chondroma occurring in rare sites. Arthroscopic management is successful in patients with synovial chondromatosis combined with shoulder subluxation.

[Research status of acetabular reconstruction in Crowe type â ¡ and â ¢ developmental dysplasia of the hip].

Developmental dysplasia of the hip (DDH) is a major cause of hip arthritis and ultimately total hip arthroplasty. Due to the dysplastic acetabulum, how to place the acetabular cup becomes a challenge in acetabular reconstruction for such patients. Especially in the acetabula classified as Crowe typeⅡand type Ⅲ, the dislocation of the femoral head causes bone defects above the true acetabulum, which will affect the stability of the acetabular cup when the acetabular reconstruction is performed at the true acetabulum. Many acetabular reconstruction methods such as bone grafting, the use of small acetabular cups, socket medialization technique, and high hip center technique are used to increase the host bone coverage of the cup. However, each method has its own shortcomings that can not be ignored so that there is no unified conclusion on the acetabular reconstruction methods for Crowe typeⅡand type Ⅲ hip dysplasia. This article summarized and evaluated various reconstruction methods in combination with the acetabular morphology of DDH, and put forward the research direction in the future.

Slipped capital femoral epiphysis with hypopituitarism in adults: A case report and literature review.

RATIONALE: Slipped capital femoral epiphysis (SCFE) is a common disease in pediatric orthopedics. Most research on SCFE has focused on high-risk groups or the whole population, and studies focusing on adult SCFE patients are rare. In the present study, we report the case of an adult patient with SCFE. PATIENT CONCERN: A 37-year-old man presented to our clinic with persistent pain that was poorly localized to both hips, groin regions, and thighs for more than 1 year. DIAGNOSES: A bilateral hip X-ray examination was performed, and the femoral epiphyses were found to be unfused on both sides. Low levels of growth hormone (GH), insulin-like growth factor-1 (IGF-1), triiodothyronine (T3), thyroxine (T4), follicle-stimulating hormone, luteinizing hormone, estradiol, and testosterone, and high levels of thyroid-stimulating hormone, prolactin, and cortisol. INTERVENTIONS: Hormone-substitution therapies (levothyroxine sodium to treat hypothyroidism and testosterone enanthate to treat hypogonadism) were prescribed. Total hip arthroplasty was performed to treat femoral epiphysis slippage. OUTCOMES: After 6 months of postoperative follow-up, the patient's gait improved significantly, and bilateral hip pain was relieved. LESSONS: When treating adults with SCFE, clinicians must be alert to endocrine disorders. Comprehensive imaging evaluation is crucial for the accurate diagnosis and selection of an appropriate treatment.

The MRI-based 3D morphologic changes of knee meniscus under knee weight-bearing and early flexion conditions.

There are few studies investigate morphologic changes of knee meniscus in vivo mechanical loading and three-dimensions (3D) deformation and displacement of the whole meniscus between in vivo mechanical loading and unloading conditions are still unclear. To investigate the displacements and 3D morphological changes of the menisci under knee weight-bearing and early flexion conditions in healthy adults using a Magnetic Resonance Imaging (MRI)-compatible loading device (a 3.0 T MR imaging system) combined with a newly developed 3D comparison technique. Fifteen healthy volunteers were recruited in this cross-sectional observational study. Each subject underwent MRIs of their dominant right knee in eight different scanning conditions using a 3.0-T MRI scanner with a custom-made MRI-compatible loading device. The knee meniscus images were 3D reconstructed, and dimensional comparisons were made for each meniscal model with baseline (0°-unloaded model). The morphologic changes of the meniscal-anterior horn (AH), body (BD), and posterior horn (PH) regions were expressed as mean positive and negative deviations. The displacements were further investigated, and the meniscal extrusions of different subregions were measured. The morphologic changing patterns of human meniscus under loading and flexions were presented using 3D chromatic maps. The bilateral menisci were generally shifting laterally and posteriorly in most flexion angles and were changing medially and anteriorly under fully extended knee loading conditions. The mean deviations were more significant with loading at 0° of knee flexion, while the PH region in the lateral side changed further posteriorly with loading in 30° flexion. Most of the differences were not significant in other flexion angles between loading conditions. The extrusion of meniscus's medial body was greater in full extension compared to any other flexing angles. Mechanical loading can significantly deform the menisci in knee extension; however, this effect is limited during knee flexion. Current study can be used as a reference for the evaluations of the integrity in meniscal functions.

Effects of the depth of the acetabular component during simulated acetabulum reaming in total hip arthroplasty.

We aimed to evaluate whether there are differences in the rotation center, cup coverage, and biomechanical effects between conventional and anatomical technique. Computed tomography scans of 26 normal hips were used to simulate implantation of acetabular component. The hip rotation center and acetabular component coverage rate were calculated. Moreover, a finite element model of the hip joint was generated to simulate and evaluate the acetabular cup insertion. Micromotion and the peak stress distribution were used to quantify the biomechanical properties. The medial and superior shifts of the rotation center were 5.2 ± 1.8 mm and 1.6 ± 0.7 mm for the conventional reaming technique and 1.1 ± 1.5 mm and 0.8 ± 0.5 mm for anatomical technique, respectively. The acetabular component coverage rates for conventional reaming technique and anatomical technique were 86.8 ± 4% and 70.0 ± 7%, respectively. The micromotion of the cup with conventional reaming technique was greater than that with anatomical technique. The peak stress concentration was highest in the superior portion with conventional reaming technique, whereas with anatomical technique, there was no stress concentration. Paradoxically although the acetabular component coverage rate is larger with conventional reaming technique, anatomical technique provides less micromotion and stress concentration for initial cup stability. Thus, anatomical technique may be more suitable for acetabulum reaming during primary total hip arthroplasty.

Comparison of the Sterilization Efficiency of 3 Disinfectants for Dropped Anterior Cruciate Ligament Grafts: A Systematic Review and Meta-analysis.

BACKGROUND: The inadvertent contamination of anterior cruciate ligament (ACL) grafts can occur if they are accidentally dropped on the floor during ACL reconstruction. There has been no meta-analysis conducted to compare the sterilization efficiency of the different disinfectants used on dropped ACL grafts. PURPOSE: To compare the sterilization efficiency of 3 disinfectants to decontaminate ACL grafts as necessary. STUDY DESIGN: Systematic review. METHODS: A systematic literature review was performed using the MEDLINE, Embase, and Cochrane Library databases. All studies reporting the management of dropped or contaminated grafts were considered for this meta-analysis. RESULTS: A total of 7 studies meeting inclusion criteria were identified from a literature search. The pooled results of this meta-analysis indicated that the rate of positive cultures of ACL grafts dropped on the operating room floor was 44.9% and that the commonly contaminated microbes were staphylococci and bacilli. The meta-analysis results indicated that the sterilization efficiency of a 4% chlorhexidine solution was superior to an antibiotic solution (odds ratio [OR], 0.17 [95% CI, 0.05-0.57]; P = .004) and a 10% povidone-iodine solution (OR, 0.04 [95% CI, 0.01-0.20]; P < .0001). Further, the antibiotic solution was superior to the 10% povidone-iodine solution (OR, 0.20 [95% CI, 0.07-0.55]; P = .002). CONCLUSION: The results of our meta-analysis demonstrated that staphylococci and bacilli were the most common contaminants on dropped ACL grafts and that decontamination using a 4% chlorhexidine solution more reliably disinfected ACL grafts. This information can help to guide surgeons as regards appropriate remedial measures.

A Systematic Review of Risk Factors for Anterior Cruciate Ligament Reconstruction Failure.

Although most studies have introduced risk factors related to anterior cruciate ligament reconstruction failure, studies on combinations of high-risk factors are rare. To provide a systematic review of the risk factors of anterior cruciate ligament reconstruction failure to guide surgeons through the decision-making process, an extensive literature search was performed of the Medline, Embase and Cochrane Library databases. Studies published between January 1, 2009, and September 19, 2019, regarding the existing evidence for risk factors of anterior cruciate ligament reconstruction failure or graft failure were included in this review. Study quality was evaluated with the quality index. Ultimately, 66 articles met our criteria. There were 46 cases classified as technical factors, 21 cases as patient-related risk factors, and 14 cases as status of the knee joint. Quality assessment scores ranged from 14 to 24. This systematic review provides a comprehensive summary of the risk factors for anterior cruciate ligament reconstruction failure, including technical factors, patient-related factors, and the factors associated with the status of the knee joint. Emphasis should be placed on avoiding these high-risk combinations or correcting modifiable risk factors during preoperative planning to reduce the rate of graft rupture and anterior cruciate ligament reconstruction failure.

Primary nonkeratinizing squamous cell carcinoma of the scapular bone: A case report.

BACKGROUND: Squamous cell carcinoma (SCC) of bone is usually caused by metastasis from the lungs, bladder, or other sites. Primary SCC of bone most frequently involves the skull bones, and primary involvement of other sites in the skeletal system is extremely rare. To date, only three such cases have been reported, which makes the diagnosis, treatment, and prognosis of this disease a challenge. CASE SUMMARY: A 76-year-old Chinese man presented to our hospital with nonspecific pain and limited mobility in the right shoulder for 4 mo. He underwent three-dimensional computed tomography reconstruction and magnetic resonance imaging of the right shoulder, which revealed an osteolytic destructive lesion in the right scapula with invasion into the surrounding muscles and soft tissues. Ultrasound-guided core needle biopsy detected a malignant tumor, and immunohistochemical analysis revealed a poorly differentiated SCC. Wide excision of the right scapular bone was performed, and pathological examination of the surgical specimen confirmed the diagnosis. At the last follow-up examination within 2 years, the patient was doing well with the pain significantly relieved in the right shoulder. CONCLUSION: Primary SCC of bone is extremely rare at sites other than the skull. Clinicians must exhaust all available means for the diagnosis of primary SCC of the bone, so greater attention can be paid to its timely and effective management. Regular and adequate follow-up is essential to help rule out metastasis and judge the prognosis.

New treatment of patellar instability after total knee arthroplasty: A case report and review of literature.

BACKGROUND: Patellar instability is an uncommon complication after total knee arthroplasty (TKA). Partial lateral patella facetectomy (LPF) with lateral retinaculum release treatment of patellar instability is rarely reported. CASE SUMMARY: We present a case of patellar instability 8 mo after primary TKA. Treatment of this complication was adapted to address the cause of the dislocation. To eliminate patellar instability, we restored the vastus medialis and performed LPF with lateral retinaculum release. We achieved normal patellar tracking. Clinical and radiographic evaluations at the 1-year postoperative follow-up were satisfactory. CONCLUSION: LPF with lateral retinaculum release represents a promising option to restore central patellar tracking in patients with patellar instability after TKA in cases without component malposition.

Morphological Analysis of Normal Meniscus on Magnetic Resonance Imaging (MRI)-Based Three-Dimensional Reconstruction Models in Healthy Chinese Adults.

BACKGROUND The purpose of this cross-sectional observational study was to determine the morphological meniscus characteristics in a normal Chinese population and assess possible relationships between demographic data and meniscal morphological parameters. MATERIAL AND METHODS We examined 116 menisci (58 lateral and 58 medial) from 29 healthy Chinese volunteers (10 men, 19 women, mean age 26 years [range, 20-33 years]) with MRI and three-dimensional reconstruction using Mimics software. The width, thickness, anteroposterior distance (APD), lateral-medial distance (LMD), and covering angle (CA) were measured on reconstructed models. Univariate analysis was used to evaluate the differences of morphological parameters between the medial and lateral menisci, between sides, and between males and females. Pearson correlation analysis was used to evaluate the correlation between meniscal morphological parameters and body height, weight, and body mass index (BMI). RESULTS Univariate analysis demonstrated that the width, thickness, APD, LMD, and CA were significantly different between lateral and medial menisci. The LMD and APD of menisci in men were significantly larger than in women. There was no significant difference in meniscal thickness and CA between males and females. The lateral meniscus dimensions were slightly larger in the right knee. According to Pearson correlation analysis, the APDs of both lateral and medial menisci were strongly correlated with height and weight (lateral: r=0.596, r=0.500; medial: r=0.684, r=0.680). CONCLUSIONS The morphologies of medial and lateral menisci were different and were not significantly correlation with each other. The meniscal width and diameter were correlated with demographic data, but the thickness and CA did not significantly differ by sex, height, or BMI.

Comparison of two different on-shelf femoral stems for Crowe type IV developmental dysplasia of the hip.

OBJECTIVE: This study was performed to evaluate the proximal anatomical compatibility of stems for treatment of Crowe IV developmental dysplasia of the hip (DDH) using a previously developed three-dimensional comparison technique. METHODS: Patients with Crowe IV DDH who underwent computed tomography were retrospectively analyzed. The femoral medullary canals were three-dimensionally reconstructed, and models of cementless modular (S-ROM; DePuy Synthes) and conical (Wagner Cone; Zimmer Biomet) implants were used for virtual implantation. The negative point percentages (NPPs) were applied to verify fitting. The average distance (deviation) and the root mean square of the distance (RMSd) were used to quantify geometric compatibilities. RESULTS: Four (16.7%) and 12 (50.0%) femoral medullary canals could not be fitted properly with either the modular or conical implant. The NPPs in the distal comparison region were significantly greater in the conical than modular group. The deviation was significantly smaller in the modular than conical group. The RMSd was also significantly smaller in the modular than conical group. CONCLUSIONS: Compared with conical implants, modular implants might be more effectively used in patients with Crowe type IV DDH. However, some Crowe IV DDH femurs with severe deformity cannot be fitted with either of these two on-shelf implants.

Multivariable analysis of anatomic risk factors for anterior cruciate ligament injury in active individuals.

OBJECTIVE: The aim of the present study was to compare the morphometric differences between patients with or without anterior cruciate ligament (ACL) injury, and identify the anatomic risk factors associated with ACL injury in active individuals. METHODS: The knee joint magnetic resonance images (MRI) of 100 subjects were included in this study. Data from the ACL-injured group (50 patients) and matched controls (50 subjects) were obtained from the same hospital. These data were analyzed by univariable analysis or multivariable conditional logistic regression analysis to examine the effects of the following variables on the risk of suffering ACL injury for the first time: TT-TG distance, medial and lateral tibial slope, intercondylar notch width and depth, femur condylar width, lateral femoral condylar depth, notch width index (NWI), notch shape index (NSI), notch depth index (NDI), and cross-sectional area (CSA). RESULTS: In the univariable analysis, the ACL-injured group had a larger TT-TG distance, increased medial and lateral tibial slope, narrower intercondylar notch width, deeper lateral femoral condylar depth, lesser NWI and NSI, and CSA when compared with the control group (P < 0.05). However, there were no significant between-group differences in intercondylar notch depth (P = 0.174), femur condylar width (P = 0.797), and NDI (P = 0.436). The multivariable analysis revealed that TT-TG distance [odds ratio (OR) = 1.37, 95% CI = 1.04-1.81, P = 0.028], medial tibial slope (OR = 1.30, 95% CI = 1.02-1.66, P = 0.036) and NWI (OR = 0.46, 95% CI = 0.24-0.91, P = 0.025) had significant multivariable associations with the sole independent risk of ACL injury. CONCLUSION: Larger TT-TG distance, increased MTS, and lesser NWI are independent anatomic risk factors for active individuals with ACL injury. LEVEL OF EVIDENCE: Case-control study; Level of Evidence, III.