Femoral Version Research Articles

Does increased fracture comminution affect femoral version after intramedullary nailing? An analysis of 307 intramedullary femoral nails

Does increased fracture comminution affect femoral version after intramedullary nailing? An analysis of 307 intramedullary femoral nails

Unveiling the Hidden Links: Anatomical and Radiological Insights into Primary Hip Osteoarthritis.

Hip osteoarthritis (HOA) is a disease with globally rising incidence that leads to disability and morbidity, overall, in older populations, and might be primary or secondary to numerous risk factors. The most common idiopathic HOA is generally a diagnosis of exclusion, with pathogenetic mechanisms largely still misunderstood. We aimed to investigate the correlation between femoral-acetabular and spinopelvic anatomical and computed tomography (CT) characteristics, and the presence of primary OA. We retrospectively analyzed CT scans from 2019 to 2021, excluding patients under 45 years or with conditions affecting the pelvis, sacrum, or lower limbs. Femoral, acetabular, and spinopelvic parameters were measured; signs of OA were analyzed in the hip and knee joints. Patients were categorized into two groups: A (isolated hip OA) and B (no OA); patients with hip OA, also presenting knee OA, were excluded from this study. In total, 232 cases were examined; statistical analyses compared CT parameters between 129 subjects from Group A and 103 patients of Group B. Group A showed a mean femoral version of 16 ± 4.53 degrees, significantly higher than Group B's 13.16 ± 4.37 degrees (p = 0.0001). Other parameters showed no significant differences. This study highlights an association between femoral version and primary hip OA.

Radiological and Anthropometrical Analysis of the Hip Joint Using Computed Tomography Scan in North Indian Population

Abstract Background: Anthropometric research on the hip joint has significant clinical implications, including (1) implant design and (2) avoiding implant mismatch complications, such as aseptic loosening and incorrect load distribution, which are mainly unknown in North India. The aim of this research is to ascertain the anatomical differences in the normal hip joint across individuals in North India and to statistically compare the results with global data. Materials and Methods: We used one hip topogram and one axial segment of the femoral head to analyze 100 people (35 females and 65 males) with normal hips between the ages of 20 and 65. In both sexes and on both sides, we determined the means of the following measurements: femoral head diameter (HD), femoral neck width (NW), femoral neck length, acetabular angle of sharp, femoral version, horizontal offset, acetabular version, and vertical offset. Results: The following are the mean parameters that were observed: (a) neck shaft angle (NSA) - 128.93°, (b) femoral HD = 4.29 cm, (c) femoral NW = 2.97 cm, (d) femoral neck length = 3.61 cm, (e) Acetabular angle of Sharp - 33.01°, (f) Acetabular version = 20.44°, (g) femoral Version = 21.57°, (h) horizontal offset = 3.62 cm, and (i) Vertical offset = 4.43 cm. Conclusion: The NSA and acetabular angle of sharp were 5°–6° more when compared to the western population while horizontal and vertical offset is comparatively less than Western population and in the Indian NSA was higher for North Eastern population than the North Indian population. The residual parameters were comparable to those found in Western literature.

Understanding the variability of the proximal femoral canal: A computational modeling study.

Statistical shape modeling (SSM) offers the potential to describe the morphological differences in similar shapes using a compact number of variables. Its application in orthopedics is rapidly growing. In this study, an SSM of the intramedullary canal of the proximal femur was built, with the aim to better understanding the complexity of its shape which may, in turn, enhance the preoperative planning of total hip arthroplasty (THA). This includes the prediction of the prosthetic femoral version (PFV) which is known to be highly variable amongst patients who have undergone THA. The model was built on three dimensional (3D) models of 64 femoral canals which were generated from pelvic computed tomography images including the proximal femur in the field of view. Principal component analysis (PCA) was performed on the mean shape derived from the model and each segmented canal. Five prominent modes of variations representing approximately 84% of the total 3D variations in the population of shapes were found to capture variability in size, proximal torsion, intramedullary femoral anteversion, varus/valgus orientation, and distal femoral shaft twist/torsion, respectively. It was established that the intramedullary femoral canal is highly variable in its size, shape, and orientation between different subjects. PCA-driven SSM is beneficial for identifying patterns and extracting valuable features of the femoral canal.

Femoral version and its clinical relevance in adult hip preservation surgery for developmental dysplasia of the hip.

Femoral version (FV) is more widely adopted with the definition as the angle between the long axis of the femoral neck and the tangent line of the posterior femoral condyles on the axial plane, and the normal range between 5 and 20°. FV can be measured by imaging and functional tests. Cross-sectional CT including both the hip and the knee is the typically used imaging technique, yet variation exists according to the different landmarks used. As MRI investigations are routinely performed preoperatively, and protocols can be easily adopted to include version measurement, they are frequently used as an alternative to CT and offers several advantages. Abnormal FV has adverse effects on the biomechanics and musculoskeletal health of the whole lower limb. It affects the lever arm of muscles and the forces that the hip and patellofemoral joints suffer, and can lead to disorders such as osteoarthritis and impingement. In adult hip preservation surgery for developmental dysplasia of the hip (DDH), abnormal FV is sometimes accompanied by other morphological abnormities of the hip, a more severe DDH, and can help predict postoperative range of motion (ROM), and postoperative impingement. Currently, the most frequently used surgical technique for abnormal FV is femoral derotational osteotomy. Many controversies are left to be solved, including the specific origin of FV, the indication for femoral derotational osteotomy, especially in patients with combined DDH and abnormal FV, and the explicit compensation mechanism of abnormal FV by tibial torsion.

How Strong Is the Ligamentum Teres of the Hip? A Biomechanical Analysis.

Intraarticular hip pain represents a substantial clinical challenge, with recent studies implicating lesions in the ligamentum teres as potential contributors. Even more so, damage to the ligamentum teres is particularly prevalent among young patients undergoing joint-preserving interventions. Although several studies have investigated the biomechanical attributes of the ligamentum teres, inconsistencies in reported findings and reliance on cadaveric or animal models have raised concerns regarding the extrapolation of results to clinical practice. Furthermore, there is a lack of research examining ligamentum teres biomechanics specifically within the relevant patient cohort-individuals who benefit from joint-preserving surgical interventions. We sought (1) to determine the biomechanical properties (ultimate load to failure, tensile strength, stiffness, and elastic modulus) of fresh-frozen ligaments from patients undergoing surgical hip dislocation, and (2) to identify patient-specific factors that are associated with them. This was an institutional review board-approved study on intraoperatively harvested ligamentum teres from 74 consecutive patients undergoing surgical hip dislocation for joint preservation (August 2021 to September 2022). After the exclusion of patients with previous surgery, posttraumatic deformities, avascular necrosis, slipped capital femoral epiphysis, and Perthes disease, 31 ligaments from 31 patients were analyzed. The mean age of the study group was 27 ± 8 years, and 61% (19) of participants were male. The main indication for surgery was femoroacetabular impingement. Standardized AP pelvic and axial radiographs and CT scans were performed in all patients for better radiological description of the population and to identify associated radiological factors. The ligament was thoroughly transected at its origin on the fossa acetabuli and at the insertion area on the fovea capitis and stored at -20°C until utilization. Specimens were mounted to a materials testing machine via custom clamps that minimized slippage and the likelihood of failure at the clamp. Force-displacement and stress-strain curves were generated. Ultimate failure load (N), tensile strength (MPa), stiffness (N/mm), and elastic modulus (MPa) were determined. Using a multivariate regression analysis and a subgroup analysis, we tested demographic, degenerative, and radiographic factors as potential associated factors. The ligamentum teres demonstrated an ultimate load to failure of 126 ± 92 N, and the tensile strength was 1 ± 1 MPa. The ligaments exhibited a stiffness of 24 ± 15 N/mm and an elastic modulus of 7 ± 5 MPa. After controlling for potential confounding variables like age, fossa/fovea degeneration, and acetabular/femoral morphologies, we found that female sex was an independent factor for higher tensile strength, stiffness, and elastic modulus. Excessive femoral version was independently associated with lower load to failure (HR 122 [95% CI 47 to 197]) and stiffness (HR 15 [95% CI 2 to 27]). Damage to the acetabular fossa was associated with reduced load to failure (HR -93 [95% CI -159 to -27]). Overall, the ligamentum teres is a relatively weak ligament. Sex, degeneration, and excessive femoral version are influencing factors on strength of the ligamentum teres. The ligamentum teres exhibits lower strength compared with other joint-stabilizing ligaments, which calls into question its overall contribution to hip stability. Young patients undergoing hip-preserving surgery are the population at risk for ligamentum teres lesions. Baseline values for load to failure, tensile strength, elastic modulus, and stiffness are needed to better understand those lesions in this cohort of interest.

Femoral Anteversion Angle as a Predictor of Anterior Hip Labral Length in Patients With Femoroacetabular Impingement Syndrome.

The relationship between hip rotational abnormalities and hip labral size has not been fully investigated. To (1) examine the correlation between rotational abnormalities of the hip and labral size, while also identifying other predictive values for hip labral size, and (2) explore whether femoral torsion will lead to increased labral size. Cross-sectional study; Level of evidence, 3. A total of 180 patients (180 hips) with femoroacetabular impingement syndrome (FAIS) (mean age, 36.81 ± 10.17 years; 67 male, 113 female) who underwent hip arthroscopic surgery between January 2021 and May 2022 were included. The femoral version (FV), acetabular version, and combined version angles were measured on computed tomography, and the labral length and height at the 12-o'clock and 3-o'clock positions were measured on magnetic resonance imaging. The hips were categorized into 3 groups based on FV angle: small (SFV; <10°); moderate (MFV; ≥10° and ≤20°), and large (LFV; >20°), and group comparisons were performed. Linear correlation and regression analysis were employed. Predictive factors for labral length were FV angle (β = 0.298; P = .02), sex (β = -0.302; P < .001), and age (β = -0.169; P = .016) at 3 o'clock and lateral center-edge angle (LCEA; β = -0.208; P = .005) and age (β = -0.186; P = .011) at 12 o'clock. FV angle was positively correlated with labral length at 3 o'clock (r = 0.267; P < .001) and negatively correlated with age (r = -0.222; P = .003) and female sex (r = -0.202; P = .006). LCEA (r = -0.227; P = .002) and age (r = -0.205; P = .006) were negatively correlated with labral length at 12 o'clock. Labral length at 3 o'clock was significantly different between the LFV (n = 49 hips), MFV (n = 65 hips), and SFV (n = 66 hips) groups (9.85 ± 2.28, 8.89 ± 2.44, and 8.30 ± 2.05 mm, respectively; P = .027 for LFV vs MFV; P < .001 for LFV vs SFV). Patients with FAIS who exhibited a higher FV angle were at a greater likelihood of having a larger anterior labral length. Increased femoral anteversion and decreased LCEA, male sex, and younger age were significantly associated with longer hip labral length.

Decreased “Polar Axis Angle” is Associated With Instability After Total Hip Arthroplasty: A New Method to Assess Functional Component Position on Lateral-Seated Radiographs

BackgroundResearch on hip instability has focused on establishing “safe” ranges of combined component position in supine posture or functional placement of the acetabular component based on the hip-spine relationship. A new angle, the polar axis angle (PAA), of the total hip arthroplasty (THA) components describes the concentricity of both components and can be evaluated in functional positions that confer a greater risk of instability (ie, sitting). The goal of this study was to compare the PAA in functional positions between patients who experienced a postoperative dislocation and a matched control group who did not have a dislocation. MethodsAn institutional database was searched for patients experiencing a dislocation after primary THA. Patients who had postoperative full-length standing and lateral-seatedradiographs were included in the dislocator group. A control group of nondislocator patients was matched 2:1 by age, body mass index, sex, and hip-spine classification. Radiographic measurements of the neck angle, acetabular ante-inclination, and PAA were performed by 2 separate blinded, trained reviewers. ResultsThe lateral-seated neck angle and lateral-seated PAA measurements were significantly lower in the dislocator groups (n = 37) than the control group (n = 74) (23 versus 33 degrees, P < .001; 74 versus 83 degrees, P = .012, respectively). Significant differences were also observed in changes in the polar axes and neck angles between standing and seated positions (P < .001 and P < .001, respectively). When comparing patients who have mobile spines versus stiff spines within the dislocator group, there were no differences in the acetabular, neck, or PAAs. The effect of neck angle on the PAA showed a linear trend across cohorts. ConclusionsPatients who experience postoperative instability have a significantly lower PAA on lateral-seated radiographs when matched for age, sex, body mass index, and hip-spine classification. In addition, the lower seated PAA is driven more strongly by decreased functional femoral anteversion, which emphasizes the role of functional femoral version on stability in THA.

No significant change of tibiofemoral rotation after femoral rotational osteotomy in patients with patellofemoral instability.

An increased value of tibiofemoral rotation is frequently observed in patients with patellofemoral instability or maltracking. Nevertheless, the appropriate approach for addressing this parameter remains unclear so far. One potential approach for correcting tibiofemoral rotation is femoral rotational osteotomy. We hypothesized that femoral rotational osteotomy affects tibiofemoral rotation. All patients who underwent femoral rotational osteotomy between January 2018 and May 2022 were included in this study. Pre- and postoperative tibiofemoral rotation and the degree of femoral rotation were measured using two-dimensional (2D) and three-dimensional (3D) measurements. The effect of femoral rotation on tibiofemoral rotation was assessed. Forty knees (18 rightand 22 left) of 36 patients (28 femalesand 8 males) were included. Mean preoperative femoral torsion was 32.1 ± 10.1° in 2D and 30.8 ± 10.1° in 3D. Femoral rotation was performed by -14.1 ± 8.3° using 2D measurements and -15.0 ± 8.0° using 3D measurements. Tibiofemoral rotation changed from 9.9 ± 6.2° to 9.7 ± 6.0° (p = n.s.) in 2D, and from 10.2 ± 5.5° to 9.4 ± 5.4° (p = n.s.) in 3D. Tibiofemoral rotation showed no significant changes after femoral rotational osteotomy. Hence, femoral rotational osteotomy cannot be used to correct tibiofemoral rotation in addition to correcting the femoral version. Other surgical techniques need to be evaluated if correction of tibiofemoral rotation is required. Level III.

MCKIBBIN INDEX AND FEMORAL VERSION NOT PREDICTIVE OF IHOT12 CHANGE AT TWO YEARS IN PATIENTS UNDERGOING ISOLATED PERIACETABULAR OSTEOTOMY

Adult hip dysplasia AHD is a complex 3D pathology of lateral coverage, version and/or volume and is often associated with increased femoral anteversion. The Mckibbin index MI is the combination of acetabular version AV and femoral version FV and is used as a measure of anterior hip Stability/ Impingement(1). The Bernese Periacetabular osteotomy PAO is a powerful tool in treating AHD, but it does not address FV. De-rotational femoral osteotomies FO increases risk of complications, operative time and might condemn the patient to Secondary osteotomies to balance the gait. We aim to investigate the effect of MI and FV on PROMs in patients undergoing PAO only.593 PAOs identified on the Local Hip preservation registry between 01/2013 and 7/2023. PAOs for retroversion, residual Perthes and those combined with FO were excluded. Patients with no available PROMS at 2 years were excluded. Independent variables were collected from E-notes and imaging including MI and FV. A multiple linear regression analysis was performed against preoperative iHot12, and iHot12 change at 2years.The mean FV was 18.86± 12.4 SD. Mean MI was 36.07, SD 15.36. Mean preop iHot12 score was 29.83 ± 17.38 SD. Mean change in iHot12 at 2 years was+36.47 ± 28.44 SD. Females and a higher BMI were statistically correlated to a lower preoperative iHot12. A lower preop iHot12 score and a higher preop AI were correlated to a bigger change in iHot12 at 2years with statistical significance. MI and FV were not found to have a statistically significant correlation with Outcome measures,An increased Mckibbin index and femoral anteversion were not correlated with worse outcomes at two years. PAO alone in the presence of increased femoral anteversion avoids risks associated with FO which can be performed later if required.

Automating Linear and Angular Measurements for the Hip and Knee After Computed Tomography: Validation of a Three-Stage Deep Learning and Computer Vision-Based Pipeline for Pathoanatomic Assessment

BackgroundVariability in the bony morphology of pathologic hips/knees is a challenge in automating preoperative computed tomography (CT) scan measurements. With the increasing prevalence of CT for advanced preoperative planning, processing this data represents a critical bottleneck in presurgical planning, research, and development. The purpose of this study was to demonstrate a reproducible and scalable methodology for analyzing CT-based anatomy to process hip and knee anatomy for perioperative planning and execution. MethodsOne hundred patients with preoperative CT scans undergoing total knee arthroplasty for osteoarthritis were processed. A two-step deep learning pipeline of classification and segmentation models was developed that identifies landmark images and then generates contour representations. We utilized an open-source computer vision library to compute measurements. Classification models were assessed by accuracy, precision, and recall. Segmentation models were evaluated using dice and mean Intersection over Union (IOU) metrics. Contour measurements were compared against manual measurements to validate posterior condylar axis angle, sulcus angle, trochlear groove-tibial tuberosity distance, acetabular anteversion, and femoral version. ResultsClassifiers identified landmark images with accuracy of 0.91 and 0.88 for hip and knee models, respectively. Segmentation models demonstrated mean IOU scores above 0.95 with the highest dice coefficient of 0.957 [0.954-0.961] (UNet3+) and the highest mean IOU of 0.965 [0.961-0.969] (Attention U-Net). There were no statistically significant differences for the measurements taken automatically vs manually (P > 0.05). Average time for the pipeline to preprocess (48.65 +/− 4.41 sec), classify/retrieve landmark images (8.36 +/− 3.40 sec), segment images (<1 sec), and obtain measurements was 2.58 (+/− 1.92) minutes. ConclusionsA fully automated three-stage deep learning and computer vision-based pipeline of classification and segmentation models accurately localized, segmented, and measured landmark hip and knee images for patients undergoing total knee arthroplasty. Incorporation of clinical parameters, like patient-reported outcome measures and instability risk, will be important considerations alongside anatomic parameters.

How useful are indirect radiographic measurements of hip instability in borderline hip dysplasia? An MRI-based comparison to a healthy cohort

PurposeSymptomatic hips with borderline hip dysplasia (BHD) morphology pose a challenge in differentiating stable from unstable hips. The current study aims to compare indirect radiographic signs of instability in a symptomatic BHD population to those in a healthy cohort.MethodsThe study group consisted of patients with a lateral centre–edge angle (LCEA) with values 18° ≤ LCEA < 25° who underwent corrective periacetabular osteotomy (PAO) and reported an improvement in patient-reported outcome measures (PROMs). The comparison group consisted of a healthy cohort of athletes who did not complain of any hip-related symptoms and who had normal values of their hip morphological parameters (LCEA, acetabular index (AI°), alpha angle (α°), femoral version, acetabular version). Indirect signs of instability consisting of the femoro-epiphyseal acetabular roof index (FEAR), iliocapsularis-to-rectus-femoris (IC/RF) ratio and labral dimensions (height-to-length ratio) were assessed in both groups. Partial Pearson correlation, logistic multiple regression analysis and Receiver-Operating Characteristic (ROC) curve analysis were performed to determine correlations, as well as the sensitivity and specificity of these signs to differentiate between healthy hips and BHD.ResultsOn binary logistic multiple regression analysis, the FEAR Index was the only independent predictor to differentiate between BHD and healthy hips (p < 0.001). The IC/RF ratio did not achieve significance. The calculated area under the curve (AUC) was 0.93 (0.87 – 0.99, CI 95%, p < 0.001) for the FEAR Index and 0.81 (0.70 – 0.92, CI 95%, p < 0.001) for the height-length ratio. Using the predefined cut-off values (dysplastic—FEAR Index ≥ 5° or labral height-to-length ratio ≤ 0.5), 27% sensitivity/100% specificity and 20% sensitivity/ 100% specificity, were achieved. ROC analysis provided the following new thresholds: FEAR Index ≥ -5° (73% sensitivity/97% specificity); labral height-to-length ratio ≤ 0.8 (70% sensitivity, 79% specificity).ConclusionIn our cohort, the FEAR index was an independent parameter that could differentiate between borderline dysplastic and asymptomatic hips. The previously published values for both the FEAR index and labral hypertrophy ratio had a poor sensitivity in differentiating symptomatic unstable BHD from healthy hips. The cut-off values of ≥ -5° (FEAR index) and ≤ 0.8 (labral height-to-length ratio) provided acceptable sensitivity and specificity when comparing to morphological healthy hips.

Computed tomography-based automated 3D measurement of femoral version: Validation against standard 2D measurements in symptomatic patients.

To validate 3D methods for femoral version measurement, we asked: (1) Can a fully automated segmentation of the entire femur and 3D measurement of femoral version using a neck based method and a head-shaft based method be performed? (2) How do automatic 3D-based computed tomography (CT) measurements of femoral version compare to the most commonly used 2D-based measurements utilizing four different landmarks? Retrospective study (May 2017 to June 2018) evaluating 45 symptomatic patients (57 hips, mean age 18.7 ± 5.1 years) undergoing pelvic and femoral CT. Femoral version was assessed using four previously described methods (Lee, Reikeras, Tomczak, and Murphy). Fully-automated segmentation yielded 3D femur models used to measure femoral version via femoral neck- and head-shaft approaches. Mean femoral version with 95% confidence intervals, and intraclass correlation coefficients were calculated, and Bland-Altman analysis was performed. Automatic 3D segmentation was highly accurate, with mean dice coefficients of 0.98 ± 0.03 and 0.97 ± 0.02 for femur/pelvis, respectively. Mean difference between 3D head-shaft- (27.4 ± 16.6°) and 3D neck methods (12.9 ± 13.7°) was 14.5 ± 10.7° (p < 0.001). The 3D neck method was closer to the proximal Lee (-2.4 ± 5.9°, -4.4 to 0.5°, p = 0.009) and Reikeras (2 ± 5.6°, 95% CI: 0.2 to 3.8°, p = 0.03) methods. The 3D head-shaft method was closer to the distal Tomczak (-1.3 ± 7.5°, 95% CI: -3.8 to 1.1°, p = 0.57) and Murphy (1.5 ± 5.4°, -0.3 to 3.3°, p = 0.12) methods. Automatic 3D neck-based-/head-shaft methods yielded femoral version angles comparable to the proximal/distal 2D-based methods, when applying fully-automated segmentations.

An Innovative Plate Concept for Rotational Guided Growth: A Porcine Pilot Study.

Background Rotational deformities in children are currently treated with an osteotomy, acute de-rotation, and surgical fixation. Meanwhile, guided growth is now the gold standard in pediatric coronal deformity correction. This study aimed to evaluate the feasibility of a novel implant intended for rotational guided growth (RotOs Plate) in a large porcine animal model. Methodology A submuscular plate was inserted on the medial and lateral aspect of the distal femoral physis of the left femur in 6 pigs. Each plate was anchored with a screw in the metaphysis and epiphysis respectively. The plates were expected to rotate the femur externally. The right femur acted as a control in a paired design. The animals were housed for 12 weeks after surgery. MRI scanning of both femora was performed before euthanasia after 12 weeks. Rotation was determined as the difference in the femoral version on MRI between the operated and non-operated femur after 12 weeks. Results External rotation in all operated femurs was observed. The mean difference in the femoral version on MRI between operated and non-operated femurs was 12.5° (range 9°-16°). No significant changes in axial growth were detected. Conclusions This study shows encouraging results regarding rotational guided growth, which may replace current invasive surgical treatment options for malrotation in children. However, further studies addressing potential secondary deformities are paramount and should be carried out.

CORR Insights®: What Is the Influence of Femoral Version on Size, Tear Location, and Tear Pattern of the Acetabular Labrum in Patients With FAI?

CORR Insights®: What Is the Influence of Femoral Version on Size, Tear Location, and Tear Pattern of the Acetabular Labrum in Patients With FAI?

Who Are the Anatomic Outliers Undergoing Total Knee Arthroplasty? A Computed Tomography–Based Analysis of the Hip-Knee-Ankle Axis Across 1,352 Preoperative Computed Tomographies Using a Deep Learning and Computer Vision–Based Pipeline

BackgroundDissatisfaction after total knee arthroplasty (TKA) ranges from 15 to 30%. While patient selection may be partially responsible, morphological and reconstructive challenges may be determinants. Preoperative computed tomography (CT) scans for TKA planning allow us to evaluate the hip-knee-ankle axis and establish a baseline phenotypic distribution across anatomic parameters. The purpose of this cross-sectional analysis was to establish the distributions of 27 parameters in a pre-TKA cohort and perform threshold analysis to identify anatomic outliers. MethodsThere were 1,352 pre-TKA CTs that were processed. A 2-step deep learning pipeline of classification and segmentation models identified landmark images and then generated contour representations. We used an open-source computer vision library to compute measurements for 27 anatomic metrics along the hip-knee axis. Normative distribution plots were established, and thresholds for the 15th percentile at both extremes were calculated. Metrics falling outside the central 70th percentile were considered outlier indices. A threshold analysis of outlier indices against the proportion of the cohort was performed. ResultsSignificant variation exists in pre-TKA anatomy across 27 normally distributed metrics. Threshold analysis revealed a sigmoid function with a critical point at 9 outlier indices, representing 31.2% of subjects as anatomic outliers. Metrics with the greatest variation related to deformity (tibiofemoral angle, medial proximal tibial angle, lateral distal femoral angle), bony size (tibial width, anteroposterior femoral size, femoral head size, medial femoral condyle size), intraoperative landmarks (posterior tibial slope, transepicondylar and posterior condylar axes), and neglected rotational considerations (acetabular and femoral version, femoral torsion). ConclusionsIn the largest non-industry database of pre-TKA CTs using a fully automated 3-stage deep learning and computer vision-based pipeline, marked anatomic variation exists. In the pursuit of understanding the dissatisfaction rate after TKA, acknowledging that 31% of patients represent anatomic outliers may help us better achieve anatomically personalized TKA, with or without adjunctive technology.

Can a clinical assessment predict the functional status progression in patients with femoroacetabular impingement syndrome?

BackgroundFemoroacetabular impingement syndrome (FAIS) is a hip joint motion-related clinical disorder with a triad of symptoms, clinical signs, and imaging findings. However, scientific evidence is still unclear regarding the best treatment for FAIS. ObjectivesTo assess the value of a physical therapy evaluation in predicting the progression of functional status over the subsequent years in patients with FAIS who are candidates for hip arthroscopy surgery. MethodsIn this case-series study, patients with FAIS, candidates for hip arthroscopy surgery, underwent a standard physical therapy evaluation. Baseline data were collected between 2013 and 2019. In 2020/2021, the patients’ functional status was assessed through the International Hip Outcome Tool (iHOT-33). Functional status progression was calculated as the difference between the follow-up and baseline iHOT-33 scores. A multivariate forward stepwise regression analysis was conducted to explore the relationship between baseline characteristics and the functional status progression. ResultsFrom 353 patients who completed the baseline assessment, 145 completed the iHOT-33 follow-up. The mean (±SD) follow-up time was 58.7 (27.2) months (minimum 12 and maximum 103 months). The iHOT-33 scores increased 20.7 (21.8) points on average, ranging from -39.8 to 76.9 points. Among the 15 potential predictive factors assessed in this study, only baseline iHOT-33 score (β -0.44; -0.061, -0.27), femoral version (β 9.03; 1.36, 16.71), and body mass index (β -0.99; -1.98, -0.01) had the ability to predict the functional status progression. ConclusionPatients with a lower baseline iHOT-33 score, lower body mass index, and normal femoral version were more likely to increase their functional status after a minimum of one year of follow-up.

Evaluation of Intraoperative Fluoroscopic Techniques to Estimate Femoral Rotation: A Cadaveric Study.

To compare three fluoroscopic methods for determining femoral rotation. Native femoral version was measured by computed tomography in 20 intact femurs from 10 cadaveric specimens. Two Steinmann pins were placed into each left femur above and below a planned transverse osteotomy which was completed through the diaphysis. Four surgeons utilized the true lateral (TL), neck-horizontal angle (NH), and lesser trochanter profile (LTP) techniques to correct the injured femur's rotation using the intact right femur as reference, yielding 120 measurements. Accuracy was assessed by comparing the angle subtended by the two Steinmann pins before and after manipulation and comparing against version measurements of the right femur. Absolute mean rotational error in the fractured femur compared to its uninjured state was 6.0° (95% CI, 4.6-7.5), 6.6° (95% CI, 5.0-8.2), and 8.5° (95% CI, 6.5-10.6) for the TL, NH, and LTP techniques, respectively, without significant difference between techniques ( p = 0.100). Compared to the right femur, absolute mean rotational error was 6.6° (95% CI, 1.0-12.2), 6.4° (95% CI, 0.1-12.6), and 8.9° (95% CI, 0.8-17.0) for the TL, NH, and LTP techniques, respectively, without significant difference ( p = 0.180). Significantly more femurs were malrotated by >15° using the LTP method compared to the TL and NH methods (20.0% vs 2.5% and 5.0%, p = 0.030). Absolute mean error in estimating femoral rotation of the intact femur using the TL and NH methods compared to CT was 6.6° (95% confidence interval [CI], 5.1-8.2) and 4.4° (95% CI, 3.4-5.4), respectively, with significant difference between the two methods ( p = 0.020). The true lateral (TL), neck-horizontal angle (NH), and the lesser trochanter profile (LTP) techniques performed similarly in correcting rotation of the fractured femur, but significantly more femurs were malrotated by >15° using the LTP technique. This supports preferential use of the TL or NH methods for determining femoral version intraoperatively.

Determination of optimal component positioning in THA using 3D preoperative planning.

Advancements in three-dimensional (3D) preoperative planning tools can offer surgeons and design engineers detailed feedback and additional opportunities for clinical advancements. The objective of this study is to use a 3D total hip arthroplasty preoperative planning tool to compare femoral component alignment for three different stem systems. The planning tool in this study used morphology data of femoral bones gathered from a CT database, seven from postoperative patients and 63 from statistical shape models (SSMs), to suggest specific implant sizes and optimal placements in 3D to match each specific bone model. Retrospective validations of predicted stem size and femoral version were first performed by comparing planner-chosen and surgeon-implanted stem sizes and version angles for the seven postoperative patients. Next, the alignment of three different stem systems was evaluated using bone models generated from SSMs, with a quantitative focus on component head positioning. In the validation study, the planner accurately selected stem size and orientation compared to the surgeon for all assessed subjects. In the stem evaluation, the three stem systems yielded different accuracies in component placement, with the newest stem system demonstrating the closest restoration of anatomical head center location. It is evident that new stem designs may have the potential for increased accuracy over their predecessors, demonstrating that new stem designs can offer improved intraoperative and postoperative alignment potential. The 3D preoperative planning tools can provide novel and reliable data to both surgeons and design engineers, which can ultimately improve clinical outcomes and future implant designs.

Multivariate linear-mixed analysis of changes in anterior inferior iliac spine impingement incidence with posterior pelvic tilt: a computer simulation study.

It is well known that increased posterior tilt of the pelvis is an effective strategy for avoiding impingement of the femur with the pelvis during movement. Daily repetitive collisions become mechanical loads, and the more frequently they occur, the more tissue damage and pain they cause. Therefore, reducing the rate of occurrence of impingement is important to avoid aggravation of symptoms. This study aimed to evaluate the effects of changes in posterior pelvic tilt on the risk of impingement between the femur and the anterior inferior iliac spine (AIIS)/subspine in various functional postures. Patients with femoroacetabular impingement syndrome (FAIS) who were candidates for hip arthroscopic osteochondroplasty between October 2013 and June 2020 were included. A three-dimensional reconstructed model was used to simulate the incidence of impingement at 12 hip positions required for activities of daily living. We predicted value of the spatial incidence of impingement assumed that hip motion should exceed 130/30 degrees without impingement. Impingement was measured at three pelvic positions: an anterior tilt of 10°, in the functional pelvic plane and a posterior tilt of 10°. Multivariate linear-mixed models were used to assess the effect of covariate-adjusted posterior pelvic tilt on the impingement incidence in the AIIS region. AIIS type, center-edge angle, acetabular version and femoral version were used as covariates. The impingement rates and locations of the three pelvic tilt postures were assessed. Seventy-eight patients (60 males and 18 females; average age, 46 ± 15.1 years) with FAIS were analyzed. A multivariate linear-mixed model revealed a coefficient of -0.8% (95% confidence interval -0.9 to -0.7%; P < 0.001) for posterior pelvic tilt. Thus, posterior pelvic tilt affects AIIS impingement incidence. After adjusting for anatomical effects, the posterior pelvic tilt should be addressed to avoid impingement.