Anteroposterior Pelvic Radiographs Research Articles

Is There a Relationship Between the Functional Level of Juvenile and Adolescent Patients With Down Syndrome and Hip Dysplasia?

The prevalence of hip dysplasia among patients with Down syndrome (DS) is higher than in the general population. We hypothesize that a relationship may exist between functional level and hip dysplasia in DS, but this has not been studied to date. The aim of this study is to evaluate whether there is a relationship between functional level and radiographic parameters of hip dysplasia or other measures. Retrospective cross-sectional comparative study of 652 patients with DS from a pediatric referral center database. Patients over 8 years of age with an anteroposterior pelvis radiograph and with no exclusion criteria were selected, totaling 132 patients (264 hips; 54.55% females; mean age 12.96 ± 2.87 y). Several radiographic parameters of the acetabulum [Sharp angle (SA), Tönnis angle (TA), Wiberg center-edge angle (W-CEA), extrusion index (EI), and acetabular retroversion signs], the proximal femur [neck shaft angle (NSA)], and joint congruence [Shenton line (SL)] were assessed. Patients were classified into 2 levels based on functional skills. A multivariate association analysis was performed between radiographic parameters and functional level. Sixty-one patients were compatible with a functional level I and 71 with a level II. Forty-six hips were dysplastic and 60 were borderline according to the W-CEA. A statistically significant relationship was found between the categorical distribution of certain radiographic measurements of hip dysplasia (EI, SA, TA, W-CEA, SL, and classification by functional level ( P < 0.0005). A significant receiver operating characteristic curve was obtained for W-CEA with a cutt-off point at 26.4 degrees for level I (area under the curve = 0.763; P < 0.005; sensitivity = 0.800 and specificity = 0.644). There was a fairly high correlation between EI and TA (0.749; P < 0.0005), EI and W-CEA (-0.817; P < 0.0005), and TA and W-CEA (-0.748; P < 0.0005). Numerous hips showed signs of acetabular retroversion, with no significant differences found between functional levels or association with hip dysplasia measures. The present study reveals a relationship between an increased risk of hip dysplasia and reduced functional levels in DS children older than 8 years. These findings may guide individualized clinical follow-up of hip development in DS children considering their functional level. Level III, retrospective comparative study.

Pubic Symphysis to Sacrococcygeal Joint: A Poor Correlate to Other Spinopelvic Measurements

BackgroundThe hip-spine relationship is increasingly recognized as critical for optimizing stability following total hip arthroplasty (THA). However, these measurements are not routinely obtained during THA workup. It has been suggested that insight can be gained from supine antero-posterior pelvis radiograph, measuring the distance from the superior border of the pubic symphysis to the sacro-coccygeal joint (PSCD). This study assessed the correlation between PSCD and lateral lumbar radiographic metrics in a cohort of preoperative THA patients. MethodsWe retrospectively evaluated 250 consecutive patients who underwent THA with preoperative supine antero-posterior pelvis and lateral lumbar radiographs. The mean age was 68 years (range, 42 to 89), 61% were women, and the mean body mass index was 30 kg/m2 (range, 19 to 52). Two reviewers measured PSCD, pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), and lumbar lordosis (LL). Inter-observer reliability was calculated for all measurements, and correlation coefficients were calculated for PSCD with respect to PT, SS, PI, and LL. ResultsCorrelations between PSCD and lumbar radiographic metrics were all statistically significant, except for PI in men but graded as “weak” or “very weak” for men and women, respectively, as follows: PT = −0.30 (P < .01) and −0.46 (P < .01); SS = 0.27 (P < .01) and 0.22 (P < .01); PI = −0.04 (P = .70) and −0.19 (P = .02); and LL = 0.45 (P < .01) and 0.30 (P < .01). Inter-observer reliability was graded as “strong” for every metric. ConclusionThe PSCD was weakly correlated with all evaluated lateral lumbar radiographic metrics in both sexes, despite strong inter-observer reliability. Therefore, PSCD cannot reliably serve as a proxy for evaluating the hip-spine relationship.

Measurement of pelvic tilt and rotation on AP radiographs using HipRecon: Validation and comparison to other parameters.

In this paper, we present and evaluate HipRecon, a noncommercial software package that simultaneously calculates pelvic tilt and rotation from an anteroposterior pelvis radiograph. We asked: What is the (1) accuracy and precision, (2) robustness, and (3) intra-/interobserver reliability/reproducibility of HipRecon to analyze both pelvic tilt and rotation on conventional AP pelvis radiographs? (4) How does the prediction of pelvic tilt on AP pelvis radiographs using HipRecon compare to established measurement methods? We compared the actual pelvic tilt of 20adult human cadaveric pelvises with the calculated pelvic orientation based on an AP pelvis radiograph using HipRecon software. The pelvises were mounted on a radiolucent fixture and a total of 380 AP pelvis radiographs with different configurations were acquired. In addition, we investigated the correlation between actual tilt and the tilt calculated using HipRecon and seven other established measurement methods. The calculated software accuracy was 0.2 ± 2.0° (-3.6-4.1) for pelvic tilt and 0.0 ± 1.2° (-2.2-2.3, p = 0.39) for pelvic rotation. The Bland-Altman analysis showed values that were evenly and randomly spread in both directions. HipRecon showed excellent consistency for the measurement of pelvic tilt and rotation (intraobserver intraclass-correlation coefficient[ICC]: 0.99 [95% CI: 0.99-0.99] and interobserver ICC 0.99 [95% CI: 0.99-0.99]). Of all eight analyzed methods, the highest correlation coefficient was found for HipRecon (r = 0.98, p < 0.001). In the future, HipRecon could be used to detect changes in patient-specific pelvic orientation, helping to improve clinical understanding and decision-making in pathologies of the hip.

Application of deep-learning-based artificial intelligence in acetabular index measurement.

To construct an artificial intelligence system to measure acetabular index and evaluate its accuracy in clinical application. A total of 10,219 standard anteroposterior pelvic radiographs were collected retrospectively from April 2014 to December 2018 in our hospital. Of these, 9,219 radiographs were randomly selected to train and verify the system. The remaining 1,000 radiographs were used to compare the system's and the clinicians' measurement results. All plain pelvic films were labeled by an expert committee through PACS system based on a uniform standard to measure acetabular index. Subsequently, eight other clinicians independently measured the acetabular index from 200 randomly selected radiographs from the test radiographs. Bland-Altman test was used for consistency analysis between the system and clinician measurements. The test set included 1,000 cases (2,000 hips). Compared with the expert committee measurement, the 95% limits of agreement (95% LOA) of the system was -4.02° to 3.45° (bias = -0.27°, P < 0.05). The acetabular index measured by the system within all age groups, including normal and abnormal groups, also showed good credibility according to the Bland-Altman principle. Comparison of the measurement evaluations by the system and eight clinicians vs. that of, the expert committee, the 95% LOA of the clinician with the smallest measurement error was -2.76° to 2.56° (bias = -0.10°, P = 0.126). The 95% LOA of the system was -0.93° to 2.86° (bias = -0.03°, P = 0.647). The 95% LOA of the clinician with the largest measurement error was -3.41° to 4.25° (bias = 0.42°, P < 0.05). The measurement error of the system was only greater than that of a senior clinician. The newly constructed artificial intelligence system could quickly and accurately measure the acetabular index of standard anteroposterior pelvic radiographs. There is good data consistency between the system in measuring standard anteroposterior pelvic radiographs. The accuracy of the system is closer to that of senior clinicians.

Radiographic measurement of leg-length change in the nonoperative leg during total hip arthroplasty: a potential indicator of imaging error?

Anteroposterior (AP) pelvic radiographs are subject to errors that may cause measurement inaccuracy in total hip arthroplasty (THA). Such errors may be detected by measuring pre- to postoperative leg-length changes in the nonoperative leg, which experiences no physical changes during THA. From AP pelvic radiographs, we measured pre- to postoperative leg-length changes (LLC) in the nonoperative legs of 67 patients who underwent primary THA using the trans-ischial line method. An LLC of 0 mm was observed in the nonoperative leg in only 14 cases (21%). A LLC ⩾ 2 mm was observed in 27% (18/67) of cases, including 13% (9/67) with LLC ⩾ 3 mm and 6% (4/67) with LLC ⩾ 4 mm. A post-hoc analysis used a validated method to measure change in pelvic tilt between pre- and postoperative images and found that changes in pelvic tilt ⩾ 4° in the anterior and posterior directions created apparent lengthening (2.0 ± 1.4 mm, p < 0.001 vs. 0-3° of tilt) and shortening (-2.1 ± 1.6 mm, p < 0.001 vs. 0-3° of tilt) of the nonoperative leg, respectively. The current study provides evidence of measurement errors in leg length using AP pelvic radiographs following THA. Changes in pelvic tilt may be in part responsible for these errors, with the direction of change in pelvic tilt influencing the apparent lengthening or shortening of the lower limb. Ultimately, these findings may influence the radiographic measurement and interpretation of leg-length changes following THA.

Developmental dysplasia of the hip is common in patients undergoing total hip arthroplasty under 50years of age.

Developmental dysplasia of the hip (DDH) refers to congenital and/or developmental hip instability that can result in hip joint subluxation or dislocation. When detected neonatally, conservative treatment with hip bracing can restore normal hip anatomy. Missed detection of DDH in the neonatal period or late development of DDH often requires surgical intervention to correct the abnormal anatomy. Furthermore, despite surgical intervention, residual sequelae may persist leading to early osteoarthritis of the hip joint requiring joint replacement surgery. This study investigates the prevalence of hip dysplasia in patients undergoing total hip arthroplasty (THA) under 50years of age. The hip arthroplasty database at a national referral centre was investigated from January 2014 to December 2020. In patients under 50years of age, those with an adequate pre-operative anteroposterior pelvic radiograph without previous hip arthroplasty were included, while those with inadequate radiographs were excluded. The following measurements were made on the contralateral non-operated hip: (1) lateral centre-edge angle (LCEA), (2) Tönnis angle, (3) acetabular version, (4) acetabular depth, (5) femoral head lateralisation, (6) femoral head extrusion index, and (7) acetabular depth-to-width ratio. In total, 451 patients were included in this study. Twenty two percent of the patients had hip dysplasia, based on a LCEA of<25° and 42.6% of patients had hip dysplasia, based on a Tönnis angle of>10°. The mean LCEA and Tönnis angle were 31.47±9.64 and 9.82±6.79°, respectively. Hip dysplasia is common in patients undergoing THA under the age of 50years with over 40% having dysplasia according to the Tönnis angle. Classification of primary and secondary osteoarthritis in the joint registries will benefit our knowledge on the prevalence of DDH in the adult population.

Can modified Dunn radiographs be an alternative to standing AP pelvis radiographs in the evaluation of pincer femoroacetabular impingement?

The purpose of this study was to compare modified Dunn radiographs with standing anteroposterior (AP) pelvis radiographs in respect of the tilt ratio, lateral centre-edge angle (LCEA), crossover sign, crossover percentage and joint space width measurements. The study hypothesis was that modified Dunn radiographs could be an alternative method to standing AP pelvis images in the evaluation of pincer-type femoroacetabular impingement (FAI). The study included 31 patients with a mean age of 42 years (range: 29-55 years) who had modified Dunn and standing AP pelvis radiographs taken in the radiological evaluation of non-traumatic hip pain between July 2018 and September 2022. Similar tilt ratio values were obtained on standing AP and modified Dunn images (P = 0.986). Joint space width showed a decrease in the transition from the modified Dunn position to the standing position, but the difference was not statistically significant (P = 0.161). The mean LCEA was measured as 34° ± 4° in the standing position and as 35° ± 5° in the modified Dunn position. No statistically significant difference was determined in the number of patients with a crossover sign or the crossover percentage values in these patients (P > 0.05). The data obtained in this study showed that there was no significant difference between images taken in the standing and modified Dunn positions in respect of radiological findings of pelvic tilt and pincer-type FAI. The modified Dunn radiograph is equivalent to the standing AP pelvis radiograph for the evaluation of pincer FAI.

Creating High Fidelity Synthetic Pelvis Radiographs Using Generative Adversarial Networks: Unlocking the Potential of Deep Learning Models Without Patient Privacy Concerns

BackgroundIn this work, we applied and validated an artificial intelligence technique known as generative adversarial networks (GANs) to create large volumes of high-fidelity synthetic anteroposterior (AP) pelvis radiographs that can enable deep learning (DL)-based image analyses, while ensuring patient privacy. MethodsAP pelvis radiographs with native hips were gathered from an institutional registry between 1998 and 2018. The data was used to train a model to create 512 × 512 pixel synthetic AP pelvis images. The network was trained on 25 million images produced through augmentation. A set of 100 random images (50/50 real/synthetic) was evaluated by 3 orthopaedic surgeons and 2 radiologists to discern real versus synthetic images. Two models (joint localization and segmentation) were trained using synthetic images and tested on real images. ResultsThe final model was trained on 37,640 real radiographs (16,782 patients). In a computer assessment of image fidelity, the final model achieved an “excellent” rating. In a blinded review of paired images (1 real, 1 synthetic), orthopaedic surgeon reviewers were unable to correctly identify which image was synthetic (accuracy = 55%, Kappa = 0.11), highlighting synthetic image fidelity. The synthetic and real images showed equivalent performance when they were assessed by established DL models. ConclusionThis work shows the ability to use a DL technique to generate a large volume of high-fidelity synthetic pelvis images not discernible from real imaging by computers or experts. These images can be used for cross-institutional sharing and model pretraining, further advancing the performance of DL models without risk to patient data safety. Level of EvidenceLevel III.

Femoral neck shaft angle measurement on plain radiography: is standing or supine radiograph a reliable template for the contralateral femur?

IntroductionNeck-shaft angle (NSA) is of paramount importance to orthopedic surgeons due to its implications for various pathologies of the hip and femur. The primary aim of the study was to establish if NSA measurement may be affected by imaging position (standing and supine) and provide evidence regarding whether the contralateral NSA can be used as a template. The secondary aim was to determine a reference value and precisely understand the effects of sex on NSA measurement.Materials and methodsWe measured bilateral NSA in a retrospective study of 200 standing and 200 supine anteroposterior pelvis radiographs that met the inclusion criteria, while paying special attention to bilateral hip symmetry. The overall inter-rater reliability was 0.688 (CI 0.128–0.851). Matching was performed according to sex (exact matching) and age. Paired t-test, Pearson correlation coefficient, and independent sample t-test were used (p < 0.01).ResultsA total of 400 pairs of femoral necks were reviewed, comprising of 200 males and 200 females. In the upright radiograph, the overall mean NSA was 131.21° ± 4.72°. There was no significant difference between right and left femur NSA among the patients (p = 0.95). On both sides, male NSA was higher than female NSA (p < 0.001). In supine radiograph, the overall mean NSA for the supine position was 133.06° ± 5.71°. There was a significant difference between NSA of the right and left femur among the patients in the supine position (p < 0.001). On supine radiographs there was no statistically significant difference between male and female NSA (p = 0.85).ConclusionOur findings indicated no significant variability in upright radiographs between the right and left NSA. In contrast, significant asymmetry between the right and left NSA was found in the supine radiographs. However, this study does not provide definitive clinical evidence, and further clinical-oriented research is required.Level of evidenceLevel III; retrospective comparative study.

The Hip of Children with Congenital Zika Syndrome: A Prospective Observational Study

To assess the clinical and radiographic characteristics of hip joint deformities in children with congenital Zika syndrome (CZS), and the evolution of hip joint deformities in affected infants for the first 3years of life. This prospective observational study evaluated orthopedic clinical examinations performed every 3months to assess hip flexion and extension, lateral and medial rotation, and abduction and adduction, as well as lower limb muscle length and tone. The biannual radiograph comprised anteroposterior panoramic pelvic radiographs with the lower limbs in extension. Percentage of migration was used as a radiographic study tool to measure and evaluate linear hip displacement. From November 2018 to March 2020, we followed 30 children with CZS, of whom 15 (50%) had normal pelvic radiographs on admission; 5 (33.3%) developed hip displacement by the second radiograph examination. During follow-up radiographic examinations, 20 of the 30 children (66.7%) were diagnosed with hip displacement and/or dislocation of at least 1 side, and 10 of the 30 (33.3%) remained normal. Among 30 affected patients, 13 (43.3%) had hip displacement on the right side and 9 (30%) on the left side. Logistic regression analysis revealed that spasticity (P=.0033; OR, 15.9) and ophthalmologic abnormalities (P=.0163; OR, 16.9) were associated with hip dislocation during follow-up. Pelvic radiographic follow-up for all children with CZS will complement physical examination, diagnosis, and monitoring for hip joint deformities.

Estimation of Gender from Anteroposterior Pelvis Radiograph among Nepalese population

Estimation of Gender from Anteroposterior Pelvis Radiograph among Nepalese population

Leg length discrepancy assessment in total hip arthroplasty: is a pelvic radiograph sufficient?

Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements. Strong correlations were observed for all EOS measurements (rs > 0.9). The strongest correlation with AP radiograph (inter-teardrop line) was observed for functional-ASIS-to-floor (functional) (rs = 0.57), much weaker than the correlations between EOS measurements. ASIS-to-ankle measurements exhibited a high correlation to other linear measurements and the highest ICC (rs = 0.97). Using anterior superior iliac spine (ASIS)-to-ankle, 33% of patients had an absolute LLD of greater than 10 mm, which was statistically different from the inter-teardrop LLD measurement (p < 0.005). We found that the conventional measurement of LLD on AP pelvic radiograph does not correlate well with long leg measurements and may not provide a true appreciation of LLD. ASIS-to-ankle demonstrated improved detection of potential LLD than other EOS and radiograph measurements. Full length, functional imaging methods may become the new gold standard to measure LLD.Cite this article: Bone Jt Open2022;3(12):960-968.

Labral calcification in patients with femoroacetabular impingement

Background: Histologically, several previous studies correlated labral calcification with degenerative changes of the hip joint. Also, presence of labral calcification might be associated with alteration of labral quality which in turn plays a crucial rule during decision making for management of labral tears. This study aimed describe the prevalence, patient characteristics, radiographic and arthroscopic findings of labral calcification in patients with symptomatic FAI. Materials and Methods: This retrospective study was conducted on all patients who underwent hip arthroscopy in OCM Hospital – Munich – Germany, between April 2018 and March 2020. Skeletally mature patients who underwent primary arthroscopic treatment of FAI and showed radiological radio-opacity at the site of acetabular labrum in pre-operative radiographs were gathered and thoroughly evaluated. Medical records of included patients were thoroughly reviewed with documentation of personal data including gender, age, duration of symptoms (in months) and night pain. Data from preoperative examination and clinical data including passive range of motion, anterior impingement and apprehension tests were also gathered. Preoperative antero-posterior pelvic radiographs and lateral radiographs (Lauenstein view) of the affected hip were evaluated in all patients. Results: During the study period, 611 patients underwent primary hip arthroscopy for symptomatic FAI in our hospital.

Artificial intelligence-generated hip radiological measurements are fast and adequate for reliable assessment of hip dysplasia : an external validation study.

Hip dysplasia (HD) leads to premature osteoarthritis. Timely detection and correction of HD has been shown to improve pain, functional status, and hip longevity. Several time-consuming radiological measurements are currently used to confirm HD. An artificial intelligence (AI) software named HIPPO automatically locates anatomical landmarks on anteroposterior pelvis radiographs and performs the needed measurements. The primary aim of this study was to assess the reliability of this tool as compared to multi-reader evaluation in clinically proven cases of adult HD. The secondary aims were to assess the time savings achieved and evaluate inter-reader assessment. A consecutive preoperative sample of 130 HD patients (256 hips) was used. This cohort included 82.3% females (n = 107) and 17.7% males (n = 23) with median patient age of 28.6 years (interquartile range (IQR) 22.5 to 37.2). Three trained readers' measurements were compared to AI outputs of lateral centre-edge angle (LCEA), caput-collum-diaphyseal (CCD) angle, pelvic obliquity, Tönnis angle, Sharp's angle, and femoral head coverage. Intraclass correlation coefficients (ICC) and Bland-Altman analyses were obtained. Among 256 hips with AI outputs, all six hip AI measurements were successfully obtained. The AI-reader correlations were generally good (ICC 0.60 to 0.74) to excellent (ICC > 0.75). There was lower agreement for CCD angle measurement. Most widely used measurements for HD diagnosis (LCEA and Tönnis angle) demonstrated good to excellent inter-method reliability (ICC 0.71 to 0.86 and 0.82 to 0.90, respectively). The median reading time for the three readers and AI was 212 (IQR 197 to 230), 131 (IQR 126 to 147), 734 (IQR 690 to 786), and 41 (IQR 38 to 44) seconds, respectively. This study showed that AI-based software demonstrated reliable radiological assessment of patients with HD with significant interpretation-related time savings.Cite this article: Bone Jt Open2022;3(11):877-884.

Can Pelvic Orientation Be Accurately Predicted Using One Radiographic View Alone?

AbstractPelvic positioning during total hip arthroplasty (THA) can affect the functional position of the acetabular component. A comprehensive understanding of pelvic orientation before THA is necessary to allow for proper cup positioning and mitigate the risks of postoperative complications. Measurements using anteroposterior (AP) radiographs have been described as an effective means of accurately predicting pelvic functional orientation. The purpose of our study was to describe the accuracy of assessing pelvic tilt using AP radiographs alone. An online survey was created and sent to a cohort of fellowship-trained adult reconstruction (AR) surgeons. The survey consisted of 65 standing AP pelvis radiographs. Participants were asked to score each radiograph as (1) anterior pelvic tilt more than 10 degrees, (2) posterior pelvic tilt more than 10 degrees, or (3) neutral. Responses were then compared with measurements of pelvic tilt made on lateral standing pelvic radiographs. Demographic data, such as country of practice, surgical volume, surgical approach, familiarity with spinopelvic mobility, and planning with spinopelvic mobility were evaluated. Categorical variables were compared using chi-squared analysis and analysis of variance. Continuous variables were assessed using unpaired, two-tailed Student's t-tests. A total of 45 surgeons completed the survey. The average correct predictive value of pelvic tilt between all surgeons was 53.2%. Of the responding surgeons, 51.2% performed greater than 100 cases per year. Fifty percent of surgeons reported that they were “not so familiar” or “somewhat familiar” with the principles of spinopelvic mobility. Also, 43.5% of surgeons reported that they did not routinely use spinopelvic mobility principles in THA planning. Pelvic orientation before THA is poorly predicted in our cohort of surveyed fellowship-trained AR surgeons with standing AP pelvis radiographs alone. Given the limited understanding of these principles within our cohort, preoperative evaluation of spinopelvic parameters with AP radiographs may require supplementation with lateral pelvic views to ensure detailed assessment and accurate preoperative planning. This is a prospective survey study and reflects level of evidence II.

Relationship between labral length and symptoms in patients with acetabular dysplasia before rotational acetabular osteotomy.

The aim of this study was to investigate the relationship between acetabular labral length and symptoms in patients with acetabular dysplasia. In a retrospective medical record review, 218 patients with acetabular dysplasia who had undergone rotational acetabular osteotomy were identified. After implementing the inclusion and exclusion criteria, 53 patients were analyzed for preoperative symptoms measured by the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), acetabular bone morphology parameters by anteroposterior pelvic radiographs and labral parameters by radial magnetic resonance imaging. Spearman's correlation coefficients were calculated among JHEQ scores, bone morphologic parameters and labral parameters. Multiple linear regression models to determine the predictive variables of JHEQ score and labral length were obtained. There was no correlation between bone morphologic parameters and JHEQ scores. Labral length measured anteriorly correlated with JHEQ pain {r [95% confidence interval (CI)] = -0.335 (-0.555, -0.071), P = 0.014}, movement subscale [r (95% CI) = -0.398 (-0.603, -0.143), P = 0.003], mental subscale [r (95% CI) = -0.436 (-0.632, -0.188), P = 0.001] and total JHEQ score [r (95% CI)=-0.451 (-0.642, -0.204), P = 0.001]. The multiple linear regression results showed that anterior labral length was independently associated with JHEQ subscales in some models. Meanwhile, age, acetabular head index and total JHEQ score were independently associated with anterior labral length in all models. Labral length, notably in anterosuperior area, in patients with symptomatic acetabular dysplasia was related to patient's symptom. Labral length may be an important objective image finding that can be used to assess the severity of cumulative hip instability.

Proximal femur geometry: a major predictor of proximal femur fracture subtypes.

Proximal femur geometry (PFG) represents an important risk factor for the occurrence of hip fractures. There are currently few studies regarding the correlation between PFG and the occurrence of a specific fracture subtype, and those that exist have small cohorts and present with different methodologies and contradictory results. Therefore, there is no consensus in the literature regarding this topic. The present study aimed to establish the contribution of the PFG in the occurrence of different subtypes of proximal femur fractures (PFF): intertrochanteric, neck and subtrochanteric. Analysis of 1022 plain anteroposterior pelvic radiographs of patients consecutively admitted to the emergency room of a Level 1 Trauma Centre between 2013 and 2019 after low energy trauma who presented with PFF and underwent surgical treatment. Patients were analysed considering age, gender and subtype of PFF (intertrochanteric, neck or subtrochanteric). Radiological parameters including cervicodiaphyseal angle (CDA), horizontal offset (HO), femoral neck width (FNW), femoral neck length (FNL), great trochanter-pubic symphysis distance (GTPSD), acetabular teardrop distance (ATD) and width of the intertrochanteric region (WIR) were measured and compared between the different subtypes of fractures (7154 measurements). Statistical analysis was conducted recurring to absolute measurements and measurements ratios. The correlation was assessed using t-test. There were statistically significant differences in proximal femur geometry between the different subtypes of fractures. Patients presenting with femoral neck fractures had greater CDA (132.5 ± 6.9 vs. 130.0 ± 7.3; p < 0.001) and lower HO (45.8 ± 7.4 vs. 49.0 ± 8.0; p < 0.001), HO/ATD (0.34 ± 0.068 vs. 0.37 ± 0.072; p < 0.001) and HO/GTPSD (0.26 ± 0.049 vs. 0.28 ± 0.039; p < 0.001) than patients with intertrochanteric/subtrochanteric fractures. PFG represents an important contributor to the occurrence of different fracture subtypes. Femoral neck fractures are associated with greater CDA and lower HO, HO/ATD and HO/GTPSD when compared to intertrochanteric or subtrochanteric fractures.

Use of Anatomic Radiographic Horizons for the Lateral Center-Edge Angle in the Classification of Hip Dysplasia

Background: The lateral center-edge angle of Wiberg (LCEA) and Tönnis angle (TA) rely on a “horizon” that functions as a reference point for measurements of hip dysplasia on weightbearing anteroposterior pelvis radiographs. There are 3 different horizons that are currently utilized depending on surgeon preference: (1) a line parallel to the radiographic floor (F), (2) a line that connects the inferior portions of the acetabular teardrops (ATs), or (3) a line that connects the ischial tuberosities (ITs). It is imperative to accurately assess the degree of hip dysplasia on initial workup to select the appropriate surgical intervention. Purpose: To assess how the choice of a radiographic horizon affects the measurements of the LCEA and TA. The secondary purpose was to assess how the horizon affected the classification of hips as either normal, borderline dysplastic, or dysplastic. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: The LCEA and TA were measured on all preoperative weightbearing anteroposterior pelvis radiographs for 186 consecutive patients who underwent hip preservation surgery between February 2016 and November 2020 (140 hip arthroscopic procedures, 46 combined hip arthroscopic procedures with periacetabular osteotomy), 3 times per hip, each time using an F, AT, and IT horizon. The Student t test was used to analyze the differences in the measurements of the LCEA and TA, and discordance rates in the dysplasia classification between horizons were quantified. Results: For the entire study population, the mean LCEAF (23.4°± 7.4°) was significantly greater than the mean LCEAIT (23.1°± 7.2°) (95% CI, −0.634 to −0.003; P = .047) and mean LCEAAT (23.0°± 7.1°) (95% CI, −0.723 to −0.139; P = .004). There was no difference between the LCEAIT and LCEAAT (95% CI, −0.305 to 0.080; P = .251). When stratified by hip arthroscopic surgery, the mean LCEAF (26.3°± 5.6°) was significantly greater than the mean LCEAAT (25.8°± 5.3°) (95% CI, −0.845 to −0.162; P = .004). Overall, there was a 17.7% and 18.3% discordance rate in the dysplasia classification using the LCEAIT and LCEAAT compared with the LCEAF, respectively. There were no statistically significant differences between the mean TAIT, TAAT, and TAF for the entire study population, the arthroscopic surgery group, and the combined arthroscopic surgery and periacetabular osteotomy group. Conclusion: There was no statistical difference between the AT and IT horizons for LCEA measurements. The dysplasia classification was in better agreement between the 2 anatomic horizons compared with the F horizon. The TA was not affected by changes in the horizon.

It's not arthritis! Resolution of the illusion of joint space narrowing with acetabuloplasty and labral reconstruction for the calcified labrum.

Labral calcification may be part of the natural history of untreated femoroacetabular impingement syndrome (FAIS) in certain patients, making it a potential target for intervention with the goal of preserving the hip joint. The purpose of this study was to investigate if calcified labra create the appearance of lateral joint space narrowing and report minimum 2-year patient-reported outcome measures (PROMs) after treating patients with arthroscopic acetabuloplasty and labral reconstruction. Prospectively collected data on patients who underwent primary hip arthroscopy for FAIS and labral tearing from February 2015 to April 2021 were reviewed. Patients treated with primary labral reconstruction for an intraoperatively confirmed diagnosis of labral calcification were included. A sub-analysis was performed for patients with a minimum of 2-year follow-up. Preoperative and postoperative PROMs for the modified Harris hip score, nonarthritic hip score, the International Hip Outcome Tool-12 and visual analog scale for pain were recorded. Forty-six hips (46 patients) were included, with 19 hips in the sub-analysis. There was a significant increase in apparent lateral joint space width (JSW) measured on supine anteroposterior (AP) pelvis radiographs with no significant changes in medial and central JSW and significant decreases in the lateral and anterior center-edge angles and alpha angle. Patients experienced significant increases in PROMs and high rates of achieving psychometric thresholds. Patients presenting with FAIS and calcified labra may have apparent lateral joint space narrowing on pre-operative supine AP pelvis radiographs. These patients have low rates of full-thickness femoral head and acetabular cartilage pathology, this apparent narrowing can be corrected and excellent outcomes and survivorship can be achieved, with primary labral reconstruction.

Patient-specific Hip Arthroplasty Dislocation Risk Calculator: An Explainable Multimodal Machine Learning-based Approach.

To develop a multimodal machine learning-based pipeline to predict patient-specific risk of dislocation following primary total hip arthroplasty (THA). This study retrospectively evaluated 17 073 patients who underwent primary THA between 1998 and 2018. A test set of 1718 patients was held out. A hybrid network of EfficientNet-B4 and Swin-B transformer was developed to classify patients according to 5-year dislocation outcomes from preoperative anteroposterior pelvic radiographs and clinical characteristics (demographics, comorbidities, and surgical characteristics). The most informative imaging features, extracted by the mentioned model, were selected and concatenated with clinical features. A collection of these features was then used to train a multimodal survival XGBoost model to predict the individualized hazard of dislocation within 5 years. C index was used to evaluate the multimodal survival model on the test set and compare it with another clinical-only model trained only on clinical data. Shapley additive explanation values were used for model explanation. The study sample had a median age of 65 years (IQR: 18 years; 52.1% [8889] women) with a 5-year dislocation incidence of 2%. On the holdout test set, the clinical-only model achieved a C index of 0.64 (95% CI: 0.60, 0.68). The addition of imaging features boosted multimodal model performance to a C index of 0.74 (95% CI: 0.69, 0.78; P = .02). Due to its discrimination ability and explainability, this risk calculator can be a potential powerful dislocation risk stratification and THA planning tool.Keywords: Conventional Radiography, Surgery, Skeletal-Appendicular, Hip, Outcomes Analysis, Supervised Learning, Convolutional Neural Network (CNN), Gradient Boosting Machines (GBM) Supplemental material is available for this article. © RSNA, 2022.