Measurement Of Femoral Version Research Articles

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.

Discrepancies in MR- and CT-Based Femoral Version Measurements Despite Strong Correlations

PurposeTo determine the correlation and classification consistency of femoral version measurements between MR and CT using four commonly used measurement methods. MethodsA retrospective study was performed on femoroacetabular impingement (FAI) patients who received preoperative CT and MR imaging assessment of the surgical hip and ipsilateral distal femur. Femoral version was measured using the Murphy method, the oblique method, the Reikerås method and the Lee method. Intra- and inter-rater agreements were calculated. Linear regression and Bland-Altman analysis were performed for measurements using different imaging modalities and measurement methods. Femoral version measurements within the lower quartile, the middle 2 quartiles and the upper quartile were classified into different groups based on their percentile within the sample population. Classification consistency rates between modalities and methods were calculated and compared. ResultsFifty-three patients (39.4 ± 9.1 years; 32 female) were included for analysis. Intra- and inter-rater reliability were high for all modalities and methods (intra-rater ICC range, 0.963-0.993; inter-rater ICC range, 0.871-0.960). MR- and CT-based femoral version measurements showed strong correlations for all methods, with the Lee method demonstrating the strongest association (r = 0.904), while the oblique method exhibited the lowest correlation (r = 0.684) (all P < .001). MR-based measurements were smaller than CT-based measurements with mean differences ranging from 4.5° to 10.3°. Classification consistency between MR and CT ranged from 51% to 74%, whereas the consistency between different measurement methods ranged from 68% to 85%. ConclusionsWhile strong correlations were observed between MR- and CT-based femoral version measurements, MR-based measurements were significantly smaller than their CT counterparts. Classification consistency between the modalities was moderate to high. Measurements between different methods showed strong correlations with high consistency rates. Level of EvidenceLevel III, retrospective case series.

Combined femoral and acetabular version is sex-related and differs between patients with hip dysplasia and acetabular retroversion

AimsFrequency of abnormal femoral and acetabular version (AV) and combinations are unclear in patients with developmental dysplasia of the hip (DDH). This study aimed to investigate femoral version (FV), the proportion of increased FV and femoral retroversion, and combined-version (CV, FV+AV) in DDH patients and acetabular-retroversion (AR). Patients and methodsA retrospective IRB-approved observational study was performed with 78 symptomatic DDH patients (90 hips) and 65 patients with femoroacetabular-impingement (FAI) due to AR (77 hips, diagnosis on AP radiographs). CT/MRI-based measurement of FV (Murphy method) and central AV were compared. Frequency of increased FV(FV > 25°), severely increased FV (FV > 35°) and excessive FV (FV > 45°) and of decreased FV (FV < 10°) and CV (McKibbin-index/COTAV-index) was analysed. ResultsMean FV and CV was significantly (p < 0.001) increased of DDH patients (mean ± SD of 25 ± 11° and 47 ± 18°) compared to AR (16 ± 11° and 28 ± 13°). Mean FV of female DDH patients (27 ± 16°) and AR (19 ± 12°) was significantly (p < 0.001) increased compared to male DDH patients (18 ± 13°) and AR (13 ± 8°). Frequency of increased FV (>25°) was 47% and of severely increased FV (>35°) was 23% for DDH patients.Proportion of femoral retroversion (FV < 10°) was significantly (p < 0.001) higher in patients AR (31%) compared to DDH patients (17%). 18% of DDH patients had AV > 25° combined with FV > 25°. Of patients with AR, 12% had FV < 10° combined with AV < 10°. ConclusionPatients with DDH and AR have remarkable sex-related differences of FV and CV. Frequency of severely increased FV > 35° (23%) is considerable for patients with DDH, but 17% exhibited decreased FV, that could influence management. The different combinations underline the importance of patient-specific evaluation before open hip preservation surgery (periacetabular osteotomy and femoral derotation osteotomy) and hip-arthroscopy.

Coxa valga and antetorta increases differences among different femoral version measurements : potential implications for derotational femoral osteotomy planning.

To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and radial CT images. Second, CT scans from three patients with femoral retroversion, normal femoral version, and anteversion were used to create 3D femur models, which were manipulated to generate models with different NSAs and different cam lesions, resulting in eight models per patient. Femoral version measurements were repeated on manipulated femora. Comparing the different measurement methods for femoral version resulted in a maximum mean difference of 18° (95% CI 16 to 20) between the most proximal (Lee et al) and most distal (Murphy et al) methods. Higher differences in proximal and distal femoral version measurement techniques were seen in femora with greater femoral version (r > 0.46; p < 0.001) and greater NSA (r > 0.37; p = 0.008) between all measurement methods. In the parametric 3D manipulation analysis, differences in femoral version increased 11° and 9° in patients with high and normal femoral version, respectively, with increasing NSA (110° to 150°). Measurement of femoral version angles differ depending on the method used to almost 20°, which is in the range of the aimed surgical correction in derotational femoral osteotomy and thus can be considered clinically relevant. Differences between proximal and distal measurement methods further increase by increasing femoral version and NSA. Measurement methods that take the entire proximal femur into account by using distal landmarks may produce more sensitive measurements of these differences.Cite this article: Bone Jt Open2022;3(10):759-766.

Correlation of femoral version measurements between computed tomography and magnetic resonance imaging studies in patients presenting with a femoroacetabular impingement-related complaint.

Computed tomography (CT) is considered the gold standard for femoral version measurement. However, recent data have shown magnetic resonance imaging (MRI) as another modality to measure femoral version. This study aimed to correlate MRI and CT femoral version measurements in patients presenting with a femoroacetabular impingement (FAI)-related complaint. Patients (18-35 years old) who presented to the hip preservation clinic and radiology department with a suspected FAI diagnosis from 26 December 2018 to 4 March 2020 were included. All patients had a CT and MRI of the hip, with images including both hips and knees, as per our institution's protocol for possible hip preservation surgery. Patients were excluded if they were missing views of the knees, or if they had a history or imaging appearance of any condition affecting femoral version at the femoral head (e.g. slipped capital femoral epiphysis). Femoral version was measured by three reviewers. Fifty-eight patients were included, and 36 (62%) were female. Femoral version averaged 6.1° ± 11.8° on CT and 6.5° ± 10.8° on MRI. A strong positive correlation was reported between the two imaging modalities (r: 0.81; P < 0.001). Inter-rater reliability among the three reviewers was excellent and statistically significant for measurements on both MRI [intraclass correlation coefficient (ICC): 0.95; 95% CI: 0.85, 0.99; P < 0.001] and CT (ICC: 0.97; 95% CI: 0.92, 0.99; P < 0.001). Our finding suggests that MRI is a sufficient method for measuring femoral version to determine disease etiology and treatment progression. To avoid exposing patients to ionizing radiation, physicians should not obtain CT scans to evaluate femoral version.

How frequent is absolute femoral retroversion in symptomatic patients with cam- and pincer-type femoroacetabular impingement?

AimsThe frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes.MethodsA retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed.ResultsA significantly (p < 0.001) lower mean FV was found in patients with cam-type FAI (15° (SD 10°)), and in patients with mixed-type FAI (17° (SD 11°)) compared to severe over-coverage (20° (SD 12°). Frequency of decreased FV < 10° was significantly (p < 0.001) higher in patients with cam-type FAI (28%, 46 hips) and in patients with over-coverage (29%, 11 hips) compared to severe over-coverage (12%, 5 hips). Absolute femoral retroversion (FV < 0°) was found in 13% (5 hips) of patients with over-coverage, 6% (10 hips) of patients with cam-type FAI, and 5% (7 hips) of patients with mixed-type FAI. The frequency of decreased FV< 10° combined with acetabular retroversion (AV < 10°) was 6% (8 hips) in patients with mixed-type FAI and 5% (20 hips) in all FAI patients. Of patients with over-coverage, 11% (4 hips) had decreased FV < 10° combined with acetabular retroversion (AV < 10°).ConclusionPatients with cam-type FAI had a considerable proportion (28%) of decreased FV < 10° and 6% had absolute femoral retroversion (FV < 0°), even more for patients with pincer-type FAI due to over-coverage (29% and 13%). This could be important for patients evaluated for open hip preservation surgery or hip arthroscopy, and each patient requires careful personalized evaluation.Cite this article: Bone Jt Open 2022;3(7):557–565.

Combined abnormalities of femoral version and acetabular version and McKibbin Index in FAI patients evaluated for hip preservation surgery.

ABSTRACTFrequencies of combined abnormalities of femoral version (FV) and acetabular version (AV) and of abnormalities of the McKibbin index are unknown. To investigate the prevalence of combined abnormalities of FV and AV and of abnormalities of the McKibbin index in symptomatic patients with femoroacetabular impingement (FAI), a retrospective, Institutional Review Board (IRB)-approved study of 333 symptomatic patients (384 hips) that were presented with hip pain and FAI was performed. The computed tomography/magnetic resonance imaging based measurement of central AV, cranial AV and FV was compared among five subgroups with distinguished FAI subgroups and patients that underwent a hip preservation surgery. The allocation to each subgroup was based on AP radiographs. Normal AV and FV were 10–25°. The McKibbin index is the sum of central AV and FV. Of patients that underwent a hip preservation surgery, 73% had a normal McKibbin index (20–50°) but 27% had an abnormal McKibbin index. Of all patients, 72% had a normal McKibbin index, but 28% had abnormal McKibbin index. The prevalence of combined abnormalities of FV and AV varied among subgroups: a higher prevalence of decreased central AV combined with decreased FV of patients with acetabular-retroversion group (12%) and overcoverage (11%) was found compared with mixed-type FAI (5%). Normal AV combined with normal FV was present in 41% of patients with cam-type FAI and in 34% of patients with overcoverage. Patients that underwent a hip preservation surgery had normal mean FV (17 ± 11°), central AV (19 ± 7°), cranial AV (16 ± 10°) and McKibbin index (36 ± 14°). Frequency of combined abnormalities of AV and FV differs between subgroups of FAI patients. Aggravated and compensated McKibbin index was prevalent in FAI patients. This has implications for open hip preservation surgery (surgical hip dislocation or femoral derotation osteotomy) or hip arthroscopy or non-operative treatment.

Cam Morphology Is Associated With Increased Femoral Version: Findings From a Collection of 1,321 Cadaveric Femurs

To evaluate the relationship between femoral version (FV) and α angle (AA) in a large osteological collection of human femurs. The University of Iowa-Stanford osteological collection was used to evaluate the research aims. To measure FV and AA, axial photographs of the proximal femurs were taken, referenced from the posterior condylar axis. FV and AA measurements were obtained using ImageJ software, and the relationship between FV and AA was assessed with repeated-measures analysis of variance and generalized linear models. A P value of <.05 was considered statistically significant. A total of 1321 cadaveric femurs (666 left and 655 right) in 721 cadavers were examined. The average AA for all femurs was 47.8° ± 10.9°, and the average FV for all femurs was 8.53° ± 8.09°. Overall, 191 femurs (14.5%) exhibited cam morphology (AA ≥ 60°). Of the 721 cadavers, 600 had both femurs available for side-to-side comparison. The average FV of femurs with cam morphology was significantly higher than that of femurs without cam morphology (11.70° ± 8.82° vs. 7.99° ± 8.82°, P < .001). Linear regression analysis demonstrated that increased AA was significantly correlated with increased FV (β ± standard error of the mean= 0.21 ± 0.02, P < .0001). In a large osteological collection of human femurs, a significant positive relationship between AA and increasing FV was identified. FAI and hip impingement morphology are more complex than cam or pincer morphology. Cam morphology with high femoral anteversion may allow for normal or near-normal hip mechanics without impingement, and this may partially explain the high rates of asymptomatic cam-type femoroacetabular impingement (FAI) morphology in active and general populations. Given the multiple morphological factors implicated in the development of FAI syndrome, these findings warrant further investigation.

Three Patterns of Acetabular Deficiency Are Common in Young Adult Patients With Acetabular Dysplasia.

Detailed recognition of the three-dimensional (3-D) deformity in acetabular dysplasia is important to help guide correction at the time of reorientation during periacetabular osteotomy (PAO). Common plain radiographic parameters of acetabular dysplasia are limited in their ability to characterize acetabular deficiency precisely. The 3-D characterization of such deficiencies with low-dose CT may allow for more precise characterization. The purposes of this study were (1) to determine the variability in 3-D acetabular deficiency in acetabular dysplasia; (2) to define subtypes of acetabular dysplasia based on 3-D morphology; (3) to determine the correlation of plain radiographic parameters with 3-D morphology; and (4) to determine the association of acetabular dysplasia subtype with patient clinical characteristics including sex, range of motion, and femoral version. Using our hip preservation database, we identified 153 hips (148 patients) that underwent PAO from October 2013 to July 2015. Among those, we noted 103 hips in 100 patients with acetabular dysplasia (lateral center-edge angle < 20°) and who had a Tönnis grade of 0 or 1. Eighty-six patients (86%) underwent preoperative low-dose pelvic CT scans at our institution as part of the preoperative planning for PAO. It is currently our standard to obtain preoperative low-dose pelvic CT scans (0.75-1.25 mSv, equivalent to three to five AP pelvis radiographs) on all patients before undergoing PAO unless a prior CT scan was performed at an outside institution. Hips with a history of a neuromuscular disorder, prior trauma, prior surgery, radiographic evidence of joint degeneration, ischemic necrosis, or Perthes-like deformities were excluded. Fifty hips in 50 patients met inclusion criteria and had CT scans available for review. These low-dose CT scans of 50 patients with symptomatic acetabular dysplasia undergoing evaluation for surgical planning of PAO were then retrospectively studied. CT scans were analyzed quantitatively for acetabular coverage, relative to established normative data for acetabular coverage, as well as measurement of femoral version. The cohort included 45 females and five males with a mean age of 26 years (range, 13-49 years). Lateral acetabular deficiency was present in all patients, whereas anterior deficiency and posterior deficiency were variable. Three patterns of acetabular deficiency were common: anterosuperior deficiency (15 of 50 [30%]), global deficiency (18 of 50 [36%]), and posterosuperior deficiency (17 of 50 [34%]). The presence of a crossover sign or posterior wall sign was poorly predictive of the dysplasia subtype. With the numbers available, males appeared more likely to have a posterosuperior deficiency pattern (four of five [80%]) compared with females (13 of 45 [29%], p = 0.040). Hip internal rotation in flexion was significantly greater in anterosuperior deficiency (23° versus 18°, p = 0.05), whereas external rotation in flexion was significantly greater in posterosuperior deficiency (43° versus 34°, p = 0.018). Acetabular deficiency pattern did not correlate with femoral version, which was variable across all subtypes. Three patterns of acetabular deficiency commonly occur among young adult patients with mild, moderate, and severe acetabular dysplasia. These patterns include anterosuperior, global, and posterosuperior deficiency and are variably observed independent of femoral version. Recognition of these distinct morphologic subtypes is important for diagnostic and surgical treatment considerations in patients with acetabular dysplasia to optimize acetabular correction and avoid femoroacetabular impingement.

Accuracy of Low Dose Computed Tomography Scanogram for Measurement of Femoral Version after Locked Intramedullary Nailing.

This prospective study was performed to compare the accuracy of femoral version measurements following repair of femoral shaft fractures using computed tomography (CT) scanograms with 10% of the standard dose of ionizing radiation versus standard-dose scanograms. CT scanogram protocols that used 90 and 10% of the usual dose of ionizing radiation were developed. Ten patients with comminuted femoral shaft fractures repaired with either an intramedullary (IM) nail or plate were imaged with both high- and low-dose CT scanograms. Postoperative version of both femurs was measured and compared between the two dose scans using the Bonesetter application. This was a prospective blinded controlled study at a level 1 trauma centre. Statistical analysis was performed, including standard deviation (SD) and paired t test. Significance was set at p < 0.05. Comparison of femoral version measurements between the 90 and 10% dose scanograms on the native and repaired sides were insignificant (p = 0.870 and p = 0.737, respectively). The difference between native and repaired femurs had an average error of 2.0 ± 1.1° for both the high- and low-dose scans and was insignificant (p = 0.742). Reducing the dose of ionizing radiation in a CT scanogram by 90% has no significant effect on the accuracy of femoral version measurement. This simple change can significantly reduce patient radiation exposure while accurately measuring femoral version and length.

Patient-Centered Outcomes After Hip Arthroscopy for Femoroacetabular Impingement and Labral Tears Are Not Different in Patients With Normal, High, or Low Femoral Version

The purpose of this study was to determine whether outcomes after hip arthroscopy were different based on femoral version. The inclusion criteria were diagnosis of femoroacetabular impingement (FAI) based on clinical examination and/or imaging findings and preoperative measurement of femoral version by magnetic resonance imaging. For this study, the definition of FAI was a positive impingement sign, a positive flexion-abduction-external rotation examination finding, or radiographic signs of impingement. A query of a prospective data registry identified 180 patients who matched the inclusion and exclusion criteria. Group 1 had version of less than 5° (n = 48), group 2 had version of 5° to 15° (n = 84), and group 3 had version greater than 15° (n = 48). The mean age of the patients was 35 years (range, 18 to 61 years). On radiographic examination, the mean alpha angle for all patients' injured hips was 63° (range, 42° to 88°). The mean center-edge angle was 30° (range, 20° to 43°), and mean femoral version was 9.9° (range, -16° to 29°). There was no significant difference in age, alpha angle, or center-edge angle among the 3 version groups. A significant difference in psoas release procedures (psoas impingement) was seen with increasing femoral version. The mean follow-up period was 30 months (range, 18 to 47 months). Patient-reported functional outcomes were not statistically different among the groups. Patient-reported functional outcomes after hip arthroscopy for labral tears and FAI were not different based on femoral version in this population. Although some differences were observed regarding intraoperative findings, these also did not result in differences in patient outcomes reported at a mean follow-up of 2 years. Level IV, therapeutic case series.

A semi-automated method for measuring femoral shape to derive version and its comparison with existing methods.

The measurement of femoral version is important in surgical planning of derotational osteotomies particularly for patients with proximal femoral deformity. It is, however, difficult to measure version accurately and differences of 10° to 15° have been found between repeated measurements. The aim of this work was first to develop a method of measuring femoral version angle where the definition of the neck axis is based on the three-dimensional point cloud making up the neck, second to automate many of the processes involved thus reducing the influence of human error and third to ensure the method could run on freely available software suitable for most computer platforms. A CT scan was performed on 44 cadaveric femurs to generate point clouds of the femoral surfaces. The point clouds were then analysed semi-automatically to determine femoral version angle between a neck axis defined by the bone surface points belonging only to the neck and a femoral condylar axis. The results from the neck fitting method were compared against three other methods typically used in the clinic (Murphy, Reikeras and Lee methods). Version angle measured by the new method gave 19.1° ± 7.3° (mean ± standard deviation) for the set of cadaveric femurs, 3.5° lower than the Murphy method and 6.8° and 11.0° higher than the Reikeras and Lee 2D methods respectively. The results demonstrate a method of measuring femoral version angle incorporating a high level of automation running on free software.

Impact of specialty and level of training on CT measurement of femoral version: an interobserver agreement analysis

BackgroundTo determine the interobserver agreement on femoral version measurements between an orthopedic attending, orthopedic senior and junior residents, and an attending radiologist.Materials and methodsPostoperative computed tomography (CT) scanograms of 267 patients who underwent femoral intramedullary (IM) nailing with corresponding radiology attending reads for femoral version were collected and de-identified. Femoral version measurements performed by a trauma fellowship-trained attending orthopedic surgeon (ORTHO), a senior orthopedic resident (PGY4), a junior orthopedic resident (PGY1), and a musculoskeletal fellowship-trained attending radiologist (RADS) were compared via Pearson’s interclass correlation coefficient to assess interobserver level of agreement.ResultsVersion measurements provided by the two attending physicians exhibited the highest level of agreement (r = 0.661, p < 0.01). The orthopedic attending and the senior resident had the next highest level of agreement (r = 0.543, p < 0.01). The first-year orthopedic resident had the weakest agreement across the board: with the orthopedic attending, the radiology attending, and the senior resident.ConclusionRegardless of specialty, experience and higher levels of training produce stronger agreement when measuring femoral version. Residents in training, especially those who are junior, produce weak agreement when compared to their senior colleagues.Level of evidenceLevel III, diagnostic study.