Anteroposterior Knee Radiographs Research Articles

Comparison of Imaging Characteristics in Pediatric Patients With Trochlear Versus Medial Femoral Condyle Osteochondritis Dissecans.

Although osteochondritis dissecans (OCD) lesions are well-described in the femoral condyles and have been associated with varus limb alignment, there is limited data on OCD lesions in the trochlea. To compare the baseline imaging characteristics in pediatric patients with trochlear OCD with those with medial femoral condyle (MFC) OCD to understand whether measures of coronal plane alignment predispose to OCD development by anatomic location. Cross-sectional study; Level of evidence, 3. This study retrospectively reviewed all pediatric patients (age ≤18 years) diagnosed with isolated trochlear OCD at a tertiary-care medical center from January 2016 to May 2023; all included patients had weight-bearing hip-to-ankle alignment radiographs. Hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), mechanical axis deviation (MAD), Caton-Deschamps Index (CDI), patellar tilt, and sulcus angle were measured on initial/preoperative anteroposterior and lateral knee radiographs. Tibial tubercle-trochlear groove (TT-TG) distance and OCD lesion size were measured on initial/preoperative magnetic resonance imaging sequences. Patients were 1 to 2 matched based on age (±2 years) and sex to a cohort with isolated MFC OCD. A total of 18 extremities in 16 patients were included in the trochlear OCD cohort and matched to 36 extremities in the MFC OCD cohort. The mean age at the first clinical visit for all patients was 14.8 ± 1.5 years and did not differ significantly between the two groups (P = .40). The extremities with trochlear OCD had significantly less varus HKA (1°± 2° vs -1°± 2°; P = .004) and MAD (4 ± 8 vs -3 ± 8 mm; P = .004) compared with the MFC cohort as well as lower mLDFA (86°± 2° vs 88°± 2°; P = .004). There were no differences in MPTA, CDI, patellar tilt, sulcus angle, TT-TG distance, or OCD lesion size between groups. Pediatric patients with trochlear OCD had statistically less varus coronal plane alignment compared with age- and sex-matched patients with MFC OCD, with the latter exhibiting more significant varus based on the HKA and MAD.

Automatic quality assessment of knee radiographs using knowledge graphs and convolutional neural networks.

X-ray radiography is a widely used imaging technique worldwide, and its image quality directly affects diagnostic accuracy. Therefore, X-ray image quality control (QC) is essential. However, subjectively assessing image quality is inefficient and inconsistent, especially when large amounts of image data are being evaluated. Thus, subjective assessment cannot meet current QC needs. To meet current QC needs and improve the efficiency of image quality assessment, a complete set of quality assessment criteria must be established and implemented using artificial intelligence (AI) technology. Therefore, we proposed a multi-criteria AI system for automatically assessing the image quality of knee radiographs. A knee radiograph QC knowledge graph containing 16 "acquisition technique" labels representing 16 image quality defects and five "clarity" labels representing five grades of clarity were developed. Ten radiographic technologists conducted three rounds of QC based on this graph. The single-person QC results were denoted as QC1 and QC2, and the multi-person QC results were denoted as QC3. Each technologist labeled each image only once. The ResNet model structure was then used to simultaneously perform classification (detection of image quality defects) and regression (output of a clarity score) tasks to construct an image QC system. The QC3 results, comprising 4324 anteroposterior and lateral knee radiographs, were used for model training (70% of the images), validation (10%), and testing (20%). The 865 test set data were used to evaluate the effectiveness of the AI model, and an AI QC result, QC4, was automatically generated by the model after training. Finally, using a double-blind method, the senior QC expert reviewed the final QC results of the test set with reference to the results QC3 and QC4 and used them as a reference standard to evaluate the performance of the model. The precision and mean absolute error (MAE) were used to evaluate the quality of all the labels in relation to the reference standard. For the 16 "acquisition technique" features, QC4 exhibited the highest weighted average precision (98.42%±0.81%), followed by QC3 (91.39%±1.35%), QC2 (87.84%±1.68%), and QC1 (87.35%±1.71%). For the image clarity features, the MAEs between QC1, QC2, QC3, and QC4 and the reference standard were 0.508±0.021, 0.475±0.019, 0.237±0.016, and 0.303±0.018, respectively. The experimental results show that our automated quality assessment system performed well in classifying the acquisition technique used for knee radiographs. The image clarity quality evaluation accuracy of the model must be further improved but is generally close to that of radiographic technologists. Intelligent QC methods using knowledge graphs and convolutional neural networks have the potential for clinical applications.

Gap Volume Based on Computed Tomography Measurement Is a Strong Risk Factor for Delayed Gap Healing After Open-Wedge High Tibial Osteotomy

To identify factors that affect delayed gap healing after open-wedge high tibial osteotomy (OWHTO) and to determine whether large gap volume is a predictor of delayed gap healing. This retrospective study analyzed biplane OWHTO performed between 2019 and 2023 for knee osteoarthritis or osteonecrosis. The minimum follow-up period was 1 year. Delayed gap healing was defined when the medial half of the osteotomy gap area had not reached the consolidation phase by 6 months after surgery based on anteroposterior knee radiographs. Gap volume was calculated from computed tomography images. Logistic regression was performed using body height, smoking, correction angle, hinge fracture, flange thickness, and gap volume. A gap volume cutoff value for delayed gap healing was determined with receiver operating characteristic curve analysis. Gap volume was predicted with multiple linear regression. There were 80 knees in 71 patients (36 men and 44 women). The mean gap volume was 7.6 cm3. Gap healing rates at 3, 6, 9, and 12 months after surgery were 26%, 65%, 89%, and 100%, respectively. There were 25 knees with delayed gap healing. Male sex was not a significant risk factor when adjusted for body height. Multivariate logistic regression revealed that only larger gap volume was a significant risk factor (odds ratio, 1.45; P= .006). The gap volume cutoff value was 7.6 cm3, with an area under the curve of 0.74. Tall body height and a large correction angle (both P < .001) were associated with a significantly larger gap volume (R2= 0.73). Large gap volume is the most important risk factor for delayed gap healing after OWHTO. Gap volume can be predicted based on body height and correction angle. When OWHTO with substantial correction is planned for tall men, surgeons should be aware of possibly delayed gap healing. Level IV, retrospective case-control study.

Femorotibial angle on short knee radiographs fails to accurately predict the lower limb mechanical alignment. A systematic review and meta-analysis on different femorotibial angle definitions and short knee radiograph types.

Hip-knee-ankle angle (HKA) on Full Limb Radiographs (FLRs) is the gold standard for coronal knee alignment assessment. Despite the widespread utilization of the more convenient femorotibial angle (FTA) on either antero-posterior (AP) or postero-anterior (PA) short knee radiographs (SKRs), its definition and correlation with HKA remains controversial. This review is the first to systematically investigate FTA-HKA correlation and the effect of different FTA methods and SKRs. Systematic literature search (Pubmed, Scopus, Cochrane Library) followed PRISMA guidelines, to evaluate studies examining the FTA-HKA correlation. Meta-analyses compared the 3 most common FTA methods, knee center determination method and SKR types. 17 studies (2597 patients, 3234 knees) were included. The strongest correlation with HKA (r = 0.78) was found for FTA Method 1 (angle formed by lines drawn from the midpoint of tibial spines to points 10 cm above and below the joint line). No significant differences were observed when grouping the FTA methods by knee center assessment (Group I, r = 0.78; Group II, r = 0.77). AP SKRs showed a trend towards stronger FTA-HKA correlation compared to PA SKRs, in both Method 1 (r = 0.79 vs 0.75) and Method 3 (r = 0.80 vs 0.66). Irrespective of its definition or type of SKR used, FTA lacks reliable accuracy in predicting the HKA in most knees. FLRs should be used whenever precise estimation of the patient's alignment is necessary. Caution is warranted in interpreting studies investigating knee alignment or knee arthroplasty outcomes based on FTA.

Prognostic power of criteria for symptomatic early knee osteoarthritis from a 2-year longitudinal observation of the Iwaki cohort study

PurposeThis study aimed to investigate whether symptomatic early knee osteoarthritis (EKOA) effectively predicts the incidence of definitive knee osteoarthritis (DKOA) in the general Japanese population. MethodsA total of 133 women from the Japanese Iwaki cohort study were enrolled and followed-up over 2 years in order to calculate the rate of progression of EKOA to DKOA. Weight-bearing anteroposterior bilateral knee radiographs and magnetic resonance imaging (MRI) were conducted at baseline and follow-up. Radiographs were classified according to the Kellgren–Lawrence grade. The presence of cartilage lesion, bone marrow lesions, attrition, cysts, osteophytes, and meniscal lesions was evaluated according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Logistic regression analyses were performed to determine the predictive power of EKOA. ResultsOf 25 women with EKOA, 15 (60%) progressed to DKOA over 2 years, showing a relative risk (RR) of 1.44 compared with the non-osteoarthritis (non-OA) group (P ​= ​0.120). Logistic regression analysis showed associations of EKOA (P ​= ​0.048) and high body mass index (P ​< ​0.001) with progression to DKOA. Combined EKOA and meniscal lesions increased the RR for osteoarthritis incidence to 2.32 (P ​= ​0.004) compared with the non-OA group. Also, meniscus and bone marrow lesion scores on MRI of the EKOA group maintained high scores over 2 years. ConclusionsThe prognostic power of EKOA criteria was confirmed with a RR of 1.44. The combination of symptomatic EKOA criteria and MRI-detected meniscal lesions was a valuable predictor of progression to DKOA over 2 years in women without radiographic abnormalities.

Is conventional magnetic resonance imaging superior to radiography in the functional integrity evaluation of anterior cruciate ligament in patients with knee osteoarthritis?

BackgroundThe functional integrity of the anterior cruciate ligament (ACL) influences surgical decision-making in patients with knee osteoarthritis (KOA). This study aimed to compare the diagnostic value of radiography and magnetic resonance imaging (MRI) in determining the functional status of ACL.MethodsWe analyzed 306 knees retrospectively using preoperative hip-to-ankle anteroposterior standing (APS) radiographs, anteroposterior (AP) and lateral knee radiographs, AP valgus stress (VS) force radiographs, and standard orthogonal MRI. Based on the intraoperative visualization, the knees were grouped into ACL functionally-intact and ACL functionally-deficient (ACLD) groups. The diagnostic validity and reliability were calculated based on the radiograph parameters such as hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), posterior tibial slope (PTS), sagittal tibiofemoral subluxation (STFS), coronal tibiofemoral subluxation (CTFS), joint line convergence angle (JLCA), the maximum wear point of the proximal tibia plateau (MWPPT%), and MRI parameters including ACL grades and MWPPT%.ResultsHKA, MPTA, PTS, STFS, JLCA, and CTFS on APS and AP radiographs, and MWPPT% on radiographs and MRI showed a significant diagnostic value (P < 0.05). There were no statistically significant differences in the single parameters from radiographs and MRI. After constructing the logistic regression models, MRI showed higher sensitivity, specificity, and accuracy, reaching 96.8%, 79.9%, and 83.3%, respectively (P < 0.001).ConclusionsIn patients with KOA, the diagnostic value of single radiographic or MRI parameter in assessing the functional integrity of the ACL are equivalent. However, by constructing predictive models, MRI could significantly improve diagnostic validity compared with radiography.

Optimizing calibration of modern skeletal maturity systems.

Greulich and Pyle is the most used system to estimate skeletal maturity but has significant drawbacks, prompting the development of newer skeletal maturity systems, such as the modified Fels skeletal maturity systems based on knee radiographs. To create a new skeletal maturity system, an outcome variable, termed a "skeletal maturity standard," must be selected for calibration of the system. Peak height velocity and 90% of final height are both considered reasonable skeletal maturity standards for skeletal maturity system development. We sought to answer two questions: (1) Does a skeletal maturity system developed using 90% of final height estimate skeletal age as well as it would if it was instead developed using peak height velocity? (2) Does a skeletal maturity system developed using 90% of final height perform as well in lower extremity length prediction as it would if it was instead developed using peak height velocity? The modified Fels knee skeletal maturity system was recalibrated based on 90% of final height and peak height velocity skeletal maturity standards. These models were applied to 133 serially obtained, peripubertal antero-posterior knee radiographs collected from 38 subjects. Each model was used to estimate the skeletal age of each radiograph. Skeletal age estimates were also used to predict each patient's ultimate femoral and tibial length using the White-Menelaus method. The skeletal maturity system calibrated with 90% of final height produced more accurate skeletal age estimates than the same skeletal maturity system calibrated with peak height velocity (p < 0.05). The 90% of final height and peak height velocity models made similar femoral and tibial length predictions (p > 0.05). Using the 90% of final height skeletal maturity standard allows for simpler skeletal maturity system development than peak height velocity with potentially more accuracy.

Radiographic Investigation of Coronal Plane and Patellar Height and Changes Following Tibial Deflection Osteotomy for Correction of Tibial Slope in Combination With ACL Reconstruction

Background: A tibial deflexion osteotomy (TDO) is performed to decrease the sagittal tibial slope to reduce the relative risk of anterior cruciate ligament (ACL) reconstruction (ACLR) graft failure. Given that coronal plane osteotomies can cause consequential changes in the sagittal plane to patellar height and tibial slope, potential changes to coronal plane alignment and patellar height can result after a sagittal plane osteotomy. Purpose: To compare preoperative and postoperative coronal plane alignment after TDO, as well as to analyze the effect of the osteotomy on patellar height. Study Design: Case series; Level of evidence, 4. Methods: This study was conducted on a consecutive series of patients with primary and revision ACLR with concomitant TDO between 2011 and 2022. Inclusion criteria were 1-stage autograft ACLR combined with supratubercular TDO with pre- and 3 months postoperative radiographs of sufficient quality. Indications for TDO were anterior instability requiring ACL revision surgery and a posterior tibial slope (PTS) >9° or a PTS >14° in the primary ACL surgery patients. Anteroposterior and lateral knee radiographs were reviewed, and the medial proximal tibial angle (MPTA), PTS, Caton-Deschamps index (CDI), and modified Insall-Salvati ratio were measured directly from the radiographs by 2 independent reviewers. Results: A total of 68 patients were included in this study. Pre- and postoperative radiographs were performed 1 month before and 3 months after surgery, respectively. There was a significant increase in the mean MPTA of 0.95° varus (SD, 2.1°; range, increase of 4.23° valgus to increase of 7.74° varus; P < .01), a decreased PTS of 8.86° (SD, 3.03°; P < .01), and an increased CDI of 0.08 (range, decrease of 0.27 to increase of 0.64) (P < .01; SD, 0.17) in patients undergoing TDO. Insall-Salvati ratio measurements showed no difference. There was good intra- and interobserver reliability, with intraclass correlation coefficients of 0.97 and 0.91 for MPTA, 0.97 and 0.87 for PTS, 0.87 and 0.93 for CDI, and 0.88 and 0.76 the Insall-Salvati ratio. Conclusion: This study, the largest series on TDO for ACLR, demonstrates that the TDO can be performed safely without large changes to coronal alignment or patellar height. The tibial slope was reduced by a mean of 8.86° (range, 2.3°-11.5°; P < .01). The TDO produces a small statistically significant change to coronal alignment, inducing a mean increased varus of <1° and an increased patellar height of 0.1 CDI. Therefore, TDO can be performed safely without dramatic changes to coronal alignment or patellar height, this study highlights technical aspects to minimize iatrogenic varus.

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy

Background: Increased posterior tibial slope (PTS) and decreased patellar height (PH) after medial opening wedge high tibial osteotomy (MOWHTO) have been repeatedly reported in the literature. However, this has been disputed in more recent biomechanical studies. Hypothesis: No change in PTS or PH would result after MOWHTO with the freehand technique, regardless of the degree of the coronal plane correction. Study Design: Case series. Methods: A total of 62 patients who underwent MOWHTO between 2018 and 2020 were included. Surgery was performed using a dedicated step-by-step protocol to reduce the risk of unintentional slope changes. All patients were evaluated preoperatively and at a 2-year follow-up with the Knee injury and Osteoarthritis Outcome Score and the University of California, Los Angeles physical activity scale. Pre- and postoperative radiographic lower limb alignment parameters—including hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle, proximal posterior tibial angle (PPTA), joint line convergence angle, and joint line obliquity—were measured on full-length lower limb radiographs. PH measurements assessed on lateral and anteroposterior knee radiographs included the Caton-Deschamps, Insall-Salvati, and Schröter indices. Results: A significant change was observed in the coronal plane alignment, with an increase in the MPTA from 84.38° to 90.39° ( P &lt; .001) and a consequent increase in the HKA from 172.19° to 180.15° ( P &lt; .001). No significant changes were observed in the PTS, as evidenced by a postoperative PPTA of 80.6° versus a preoperative value of 80.4° ( P = .2). No significant changes were detected in the mean PH on all 3 indices used—pre- versus postoperative Caton-Deschamps, Insall-Salvati, and Schröter indices measured 0.95 versus 0.93 ( P = .2), 1.03 versus 1.03 ( P = .5), and 1.56 versus 1.54 ( P = .3), respectively. Conclusion: In this study, MOWHTO did not result in significant changes in the PTS or PH when accurate preoperative planning and precise intraoperative freehand technique were adopted..

Preoperative Joint Distraction Imaging and Planning Protocol for Total Knee Arthroplasty

BackgroundCurrent preoperative total knee arthroplasty (TKA) planning strategies are bone-referencing and do not consider the ligamentous profile of the knee. This study assessed the mean Hip-Knee-Ankle (HKA) angle of the planned Distracted Alignment (DA), an alignment output using a joint distraction radiology and planning protocol, which incorporates preoperative evaluation of ligament laxity. MethodsA retrospective study of 144 knees undergoing TKA was performed. Each patient received a preoperative computer tomograph scan, a weight-bearing antero-posterior knee radiograph, and distracted knee radiographs in extension and flexion. The imaging was used to develop a preoperative DA plan aiming for medio-lateral and extension-flexion space balance. The mean DA, weight-bearing, and arithmetic HKA angles were compared to each other, and to the HKA of a healthy nonarthritic population. ResultsThe mean weight-bearing, arithmetic, and planned DA HKA angles were 4.8° (interquartile range [IQR] 6.5°) varus, 0.4° (IQR 4.5°) varus, and 2.2° (IQR 4.0°) varus, respectively. This compares to a healthy adult HKA angle of 1.3° varus. The difference between the planned DA and arithmetic HKA angles was greater than 3° for 36% of the patients in the study population. ConclusionsThe planned DA HKA angle was fundamentally different from the arithmetic HKA angle, but comparable to a healthy population. Considering both hard and soft tissue information of the knee, we believe the planned DA resulting from the joint distraction radiology protocol allows for optimized preoperative surgical planning in TKA. This protocol has been shown to be clinically viable.

The Reliability of the Modified Fels Knee Skeletal Maturity System.

The recently described Modified Fels knee skeletal maturity system (mFels) has proven utility in prediction of ultimate lower extremity length in modern pediatric patients. mFels users evaluate chronological age, sex, and 7 anteroposterior knee radiographic parameters to produce a skeletal age estimate. We developed a free mobile application to minimize the learning curve of mFels radiographic parameter evaluation. We sought to identify the reliability of mFels for new users. Five pediatric orthopaedic surgeons, 5 orthopaedic surgery residents, 3 pediatric orthopaedic nurse practitioners, and 5 medical students completely naïve to mFels each evaluated a set of 20 pediatric anteroposterior knee radiographs with the assistance of the (What's the Skeletal Maturity?) mobile application. They were not provided any guidance beyond the instructions and examples embedded in the app. The results of their radiographic evaluations and skeletal age estimates were compared with those of the mFels app developers. Averaging across participant groups, inter-rater reliability for each mFels parameter ranged from 0.73 to 0.91. Inter-rater reliability of skeletal age estimates was 0.98. Regardless of group, steady proficiency was reached by the seventh radiograph measured. mFels is a reliable means of skeletal maturity evaluation. No special instruction is necessary for first time users at any level to utilize the (What's the Skeletal Maturity?) mobile application, and proficiency in skeletal age estimation is obtained by the seventh radiograph. Level II.

The utility of standing knee radiographs for detection of lipohemarthrosis: comparison with supine horizontal beam radiographs.

Lipohemarthrosis is a key finding in acute trauma patients and indicates an intra-articular fracture. The horizontal beam lateral radiography with supine position is known to be the best technique to demonstrate knee lipohemarthrosis. Our main purpose was to compare the sensitivity of supine and standing lateral knee radiographs to detect lipohemarthrosis. In our retrospective study, consecutive patients with lipohemarthrosis on computed tomography of the knee between October 2019 and September 2021 were included. Fractured bone, the presence of lipohemarthrosis, and image quality in both standing and supine anteroposterior and lateral knee radiographs were evaluated. Interobserver reliability of the three observers was calculated. Fisher exact chi-square and z-proportion tests were used to compare lateral and anteroposterior knee radiographs. Krippendorff's Alpha and Kappa coefficients were used for inter-observer agreement. A total of 61 patients (38 men [62.3%], 23 women [37.7%]; mean age, 43years ± 17 [standard deviation]) were included. The most common type of fracture was isolated tibial fractures (n = 32; 52.5%). The sensitivity of showing lipohemarthrosis of standing lateral knee radiographs (95.5%) was higher than supine lateral radiographs (38.5%) (p < 0.001). While non-optimal image quality did not affect lipohemarthrosis detection on lateral radiographs (p > 0.99), it caused a significant decrease in the diagnosis of lipohemarthrosis on anteroposterior radiographs (p = 0.036). We found a good-excellent interobserver agreement in lipohemarthrosis detection. Standing lateral radiographs have higher sensitivity than supine lateral radiographs in detecting lipohemarthrosis and are beneficial for detecting lipohemarthrosis which indicates the presence of occult-evident intraarticular fracture in patients with knee trauma. Standing lateral knee radiographs offer a useful method for reducing the misdiagnosis of the occult intra-articular fractures by showing the fat-fluid leveling more clearly. Its advantages may be more prominent when the advanced imaging modalities are limited. • Fat-fluid level (lipohemarthrosis) is an important radiographic sign to assess patients with acute trauma. It almost always indicates an intra-articular fracture. • Our retrospective study results support that lipohemarthrosis sign could be observed more frequently in standing lateral knee radiographs than in supine lateral radiographs. • Knee trauma patients, when available, should be evaluated with standing lateral radiographs for the diagnosis of lipohemarthrosis.

JOINT REPAIR EVALUATED ON RADIOGRAPHS IS ASSOCIATED WITH PAIN AND SYNOVIAL FLUID MARKER CHANGES AFTER KNEE JOINT DISTRACTION TREATMENT

Knee joint distraction (KJD) has been associated with clinical and structural improvement and synovial fluid (SF) marker changes. However, structural changes have not yet been shown satisfactorily in regular care, since radiographic acquisition was not fully standardized. AI-based modules have shown great potential to reduce reading time, increase inter-reader agreement and therefore function as a tool for treatment outcome assessment. The objective was to analyse structural changes after KJD in patients using this AI-based measurement method, and relate these changes to clinical outcome and SF markers.20 knee OA patients (&lt;65 years old) were included in this study. KJD treatment was performed using an external fixation device, providing 5 mm distraction for 6 weeks. SF was aspirated before, during and immediately after treatment. Weight-bearing antero-posterior knee radiographs and WOMAC questionnaires were collected before and ~one year after treatment. Radiographs were analysed with the Knee Osteoarthritis Labelling Assistant (KOALA, IB Lab GmbH, Vienna, Austria), and 10 pre-defined biomarker levels in SF were measured by immunoassay. Radiographic one-year changes were analysed and linear regression was used to calculate associations between changes in standardized joint space width (JSW) and WOMAC, and changes in JSW and SF markers.After treatment, radiographs showed an improvement in Kellgren-Lawrence grade in 7 of 16 patients that could be evaluated; 3 showed a worsening. Joint space narrowing scores and continuous JSW measures improved especially medially. A greater improvement in JSW was significantly associated with a greater improvement in WOMAC pain (β=0.64;p=0.020). A greater increase in MCP1 (β=0.67;p=0.033) and lower increase in TGFβ1 (β=-0.787;p=0.007) were associated with JSW improvement.Despite the small number of patients, also in regular care KJD treatment shows joint repair as measured automatically on radiographs, significantly associated with certain SF marker change and even with clinical outcome.

Artificial Intelligence for Automated Implant Identification in Knee Arthroplasty: A Multicenter External Validation Study Exceeding 3.5 Million Plain Radiographs

BackgroundSurgical management of complications following knee arthroplasty demands accurate and timely identification of implant manufacturer and model. Automated image processing using deep machine learning has been previously developed and internally validated; however, external validation is essential prior to scaling clinical implementation for generalizability. MethodsWe trained, validated, and externally tested a deep learning system to classify knee arthroplasty systems as one of the 9 models from 4 manufacturers derived from 4,724 original, retrospectively collected anteroposterior plain knee radiographs across 3 academic referral centers. From these radiographs, 3,568 were used for training, 412 for validation, and 744 for external testing. Augmentation was applied to the training set (n = 3,568,000) to increase model robustness. Performance was determined by the area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy. Implant identification processing speed was calculated. The training and testing sets were drawn from statistically different populations of implants (P < .001). ResultsAfter 1,000 training epochs by the deep learning system, the system discriminated 9 implant models with a mean area under the receiver operating characteristic curve of 0.989, accuracy of 97.4%, sensitivity of 89.2%, and specificity of 99.0% in the external testing dataset of 744 anteroposterior radiographs. The software classified implants at a mean speed of 0.02 seconds per image. ConclusionAn artificial intelligence-based software for identifying knee arthroplasty implants demonstrated excellent internal and external validation. Although continued surveillance is necessary with implant library expansion, this software represents a responsible and meaningful clinical application of artificial intelligence with immediate potential to globally scale and assist in preoperative planning prior to revision knee arthroplasty.

The Association Between Gonarthrosis Pain Severity and Radiographic Findings on X-Ray: A Cross-Sectional Study.

Knee osteoarthritis (KOA) is a degenerative joint disease that progresses over time due to articular cartilage loss. Orthopedic surgeons use plain radiography (X-ray) with an anteroposterior (AP) standing (weight-bearing) view, which is currently considered the gold standard modality, to diagnose KOA. They base this diagnosis on the clinical history and physical examination of the knee joint. However, many previous studies have reported a weak correlation between knee-joint structural abnormalities on X-rays and described pain. Therefore, our study aimed to assess the incompatibility between patients' pain-severity complaints and radiographic findings on standing AP view. No similar study has been recently published in the Middle East. 158 participants were selected for the study from King Abdulaziz University Hospital, Jeddah, between March 2022 and August 2022. We graded the patients' AP knee radiographs using the Kellgren-Lawrence (KL) grading scale and the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, by which we made phone calls to assess pain severity on a 0-10 pain subscale. We found a significant association between the 0-10 pain subscale and WOMAC questions describing difficulty in sitting (p < 0.05). Comparing KL scores on X-ray on a 0-10 pain subscale, we found a significant association between mild pain and severe radiological findings on X-ray and vice versa. In addition, the comparison between KL scores on X-ray and WOMAC questions describing difficulty in sitting showed a significant association between moderate difficulty in sitting and severe radiological findings and vice versa. Our results indicated that there was a significant relationship between mild pain and severe radiological findings on X-rays and vice versa. Additionally, there was a significant relationship, based on the KL score and the WOMAC item that assessed sitting difficulty, between moderate sitting difficulty and severe radiological findings and vice versa. This may suggest that central and peripheral sensitization could be one factor in the causes of pain.

Physeal fusion status and lesion size are more important than patient age for healing of juvenile osteochodritis dessicans lesions of the distal femur.

The purpose of the study was to evaluate the effect of skeletal age and lesion size, location, and grade on the success of nonoperative treatment for juvenile osteochondritis dissecans (OCD). It is hypothesized that skeletal maturity, including a combination of maturation phenotypes, correlates with nonoperative lesion healing. The clinical and radiographic data on 52 patients aged 7-20years treated for OCD of the distal femur between 2010 and 2019 were retrospectively reviewed. Knee radiographs were assessed for number of lesions present and lesion location, size, and stage. Assessments of skeletal maturation were performed on all antero-posterior knee radiographs using the Roche, Wainer, and Thissen (RWT) method. Patients were categorized as healed if they demonstrated no pain on clinical examination. The relationship between skeletal maturity and nonoperative lesion healing was determined using Spearman rank correlations on available variables. Neither chronological nor skeletal age was associated with surgical status (Rho = 0.03, n.s., and Rho = 0.13, n.s., respectively) or the healing status of nonoperatively treated OCD lesions (Rho = 0.44, n.s., and Rho = 0.03, n.s., respectively). Epiphyseal fusion status of the distal femoral physis was moderately correlated with nonoperative healing, but was not statistically significant (lateral femoral physis: Rho = 0.43, p = 0.05; medial femoral physis: Rho = 0.43, n.s.). Lesion length correlated with surgical status (Rho = -0.38, p = 0.009). The extent of fusion of the distal femoral physis (multi-stage grading) may be more strongly correlated with nonoperative healing than other markers of skeletal maturity or chronological age. Clinicians can use this as an additional radiographic sign when considering nonoperative treatment for juvenile OCD lesions in the distal femur. OCD lesion length and physeal fusion status appear to be more important for healing than patient age.

Increasing trend of radiographic features of knee osteoarthritis in rheumatoid arthritis patients before total knee arthroplasty

To investigate the trend and factors related to the occurrence of osteoarthritis (OA)-like features on knee radiographs of rheumatoid arthritis (RA) patients undergoing total knee arthroplasty (TKA) in the recent decades. To classify antero-posterior knee radiographs into ‘RA’ and ‘OA-like RA’ groups, a deep learning model was developed by training the network using knee radiographs of end-stage arthropathy in RA patients obtained during 2002–2005 and in primary OA patients obtained during 2007–2009. We used this model to categorize 796 knee radiographs, which were recorded in RA patients before TKA during 2006–2020, into ‘OA-like RA’ and ‘RA’ groups. The annual ratio of ‘OA-like RA’ was investigated. Moreover, univariate and multivariate analyses were performed to identify the factors associated with the classification as OA-like RA using clinical data from 240 patients. The percentage of ‘OA-like RA’ had significant increasing trend from 20.9% in 2006 to 67.7% in 2020. Higher body mass index, use of biologics, and lower level of C-reactive protein were identified as independent factors for ‘OA-like RA’. An increasing trend of knee radiographs with OA-like features was observed in RA patients in the recent decades, which might be attributed to recent advances in pharmacotherapy.

The winking sign is an indicator for increased femorotibial rotation in patients with recurrent patellar instability

PurposeRotation of the tibia relative to the femur was recently identified as a contributing risk factor for patellar instability, and correlated with its severity. The hypothesis was that in patellofemoral dysplastic knees, an increase in femorotibial rotation can be reliably detected on anteroposterior (AP) radiographs by an overlap of the lateral femoral condyle over the lateral tibial eminence.MethodsSixty patients (77 knees) received low-dose computed tomography (CT) of the lower extremity for assessment of torsional malalignment due to recurrent patellofemoral instability. Three-dimensional (3D) surface models were created to assess femorotibial rotation and its relationship to other morphologic risk factors of patellofemoral instability. On weight-bearing AP knee radiographs, a femoral condyle/lateral tibial eminence superimposition was defined as a positive winking sign. Using digitally reconstructed radiographs of the 3D models, susceptibility of the winking sign to vertical/horizontal AP knee radiograph malrotation was investigated.ResultsA positive winking sign was present in 30/77 knees (39.0%) and indicated a 6.3 ± 1.4° increase in femorotibial rotation (p < 0.001). Femoral condyle/tibial eminence superimposition of 1.9 mm detected an increased femorotibial rotation (> 15°) with 43% sensitivity and 90% specificity (AUC = 0.72; p = 0.002). A positive winking sign (with 2 mm overlap) disappeared in case of a 10° horizontally or 15° vertically malrotated radiograph, whereas a 4 mm overlap did not disappear at all, regardless of the quality of the radiograph. In absence of a winking sign, on the other hand, no superimposition resulted within 20° of vertical/horizontal image malrotation. Femorotibial rotation was positively correlated to TT–TG (R2 = 0.40, p = 0.001) and patellar tilt (R2 = 0.30, p = 0.001).ConclusionsThe winking sign reliably indicates an increased femorotibial rotation on a weight-bearing AP knee radiograph and could prove useful for day-by-day clinical work. Future research needs to investigate whether femorotibial rotation is not only a prognostic factor but a potential surgical target in patients with patellofemoral disorders.Level of evidenceIII.

Estimating Skeletal Maturity by Segmented Linear Modeling of Key AP Knee Radiographic Parameters.

The recently described Modified Fels knee system allows for accurate skeletal maturity estimation using a single anteroposterior knee radiograph but requires evaluation of 7 parameters. A faster method may have clinical utility in the outpatient setting. Seven anteroposterior knee radiographic parameters associated with 90% of the final height (an enhanced skeletal maturity standard compared with peak height velocity) were analyzed in 78 children. Segmented linear regression and generalized estimating equation analyses were used to identify the subsets of parameters most important for accurate skeletal maturity estimation for different patient demographics and parameter scores. This process produced abbreviated skeletal maturity systems, which include fewer parameters and are quicker to use. The accuracy of the resulting abbreviated skeletal maturity systems was evaluated and compared with the full 7-parameter Modified Fels knee system and with the Greulich and Pyle (GP) left-hand bone age. A total of 326 left knee radiographs from 41 girls (range, 7 to 15 y) and 37 boys (range, 9 to 17 y) were included. Models generated by segmented regression and generalized estimating equation analysis required fewer parameters (range, 1 to 5 parameters) than the full Modified Fels knee system (7 parameters). Skeletal age estimates produced by segmented regression models were more accurate than GP (P<0.05) and not significantly different from the full Modified Fels system (P>0.05). The percentage of outlier estimations (estimations >1 y off from actual skeletal age) made by segmented regression models was not significantly different from GP (P>0.05) or the Modified Fels knee system (P>0.05). An abbreviated version of the Modified Fels knee system estimates skeletal maturity more accurately than the GP system with just 2 to 3 radiographic knee parameters. The abbreviated Modified Fels knee system may allow for rapid skeletal age estimation (~30 s) appropriate for routine outpatient practice.

The Impact of Metabolic Syndrome on Quality of Life Among Individuals With Knee Osteoarthritis Living in Egypt.

Background:Several studies have linked metabolic syndrome (MetS) to osteoarthritis (OA), but they have not looked into how MetS can affect the health-related quality of life (HRQOL) of OA individuals.Objectives:We aimed to assess the association of MetS and its components, including obesity, hypertension, hyperglycemia, and dyslipidemia, with HRQOL among Egyptians with knee OA.Methods:This cross-sectional study comprised 116 adult Egyptian participants with knee OA. They were divided into 2 groups based on whether or not they had the MetS. All participants were subjected to a thorough medical history taking and a detailed medical examination. The Kellgren and Lawrence (K/L) scale evaluated OA in all individuals using anteroposterior knee radiographs. The Health Assessment Questionnaire-Disability Index (HAQ-DI) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were used to assess participants’ HRQOL; their higher scores indicate more disability. Spearman rank and Pearson’s correlation analyses were used to assess the association between variables.Results:Diabetes, hypertension, dyslipidemia, and obesity were significantly associated with the OA + MetS group with a prevalence of 77.6%, 82.8%, 77.6%, and 50.0%, respectively. According to the K/L scale, 70.7% of the OA + MetS group had grade IV knee affection. The HAQ-DI and WOMAC scores were significantly (P < .001) higher among the OA + MetS individuals compared with the OA individuals. Interleukin (IL)-6 serum levels were also significantly higher in the OA + MetS group (P = .036) and increased significantly with the more serious radiological damage and functional disability. We found significant positive correlations between HAQ-DI and WOMAC with waist circumference (P = .004, .001), as well as triglycerides (P = .006, .008), cholesterol (P = .041, .048), fasting blood sugar (P < .001, < .001) and significant negative correlations with high-density lipoprotein levels (P = .628, .002).Conclusions:Individuals with knee OA with MetS showed more significant radiological damage, severe functional disability, and poor HRQOL. They also had higher levels of IL-6, which correlated significantly with the degree of disability, promoting it as a significant therapeutic target.