Positive Correlation Between the Femur Neck Shaft and Anteversion Angles: A Retrospective Computed Tomography Analysis in Patients With Developmental Dysplasia of the Hip

BackgroundThis study aimed to explore the anatomical correlation between the femoral neck shaft angle (NSA) and femoral anteversion angle (AA) in patients with developmental dysplasia of the hip based on the Crowe classification and provide a novel method to estimate the femoral AA on anteroposterior pelvic radiographs.MethodsA total of 208 patients with dysplastic hips who underwent total hip arthroplasty at our institution were retrospectively included. Preoperative physiological AA and NSA were determined via 3-dimensional computed tomography. Linear regressions and Pearson’s coefficients were calculated to assess the correlation between the femoral NSA and femoral AA.ResultsA total of 416 hips were divided into 5 subgroups: 99 normal, 143 type I, 71 type II, 63 type III, and 40 type IV hips following the Crowe classification. Dysplastic femurs had significantly higher AAs than normal hips (25.2° vs 31.4° vs 33.3° vs 35.5° vs 41.7°). Significant positive correlations between the AA and NSA were observed in normal (r = 0.635), type I (r = 0.700), type II (r = 0.612), and type III (r = 0.638) hips (P < .001); however, no meaningful correlation was observed in type IV hips (r = 0.218, P = .176).ConclusionThe NSA and AA correlated positively and significantly in the normal and dysplastic Crowe type I-III hips. The relationship between the NSA and AA indicates torsion of the proximal femur and offers an opportunity for straightforward estimation of AA based on NSA.     

Asymmetrically increased femoral version with high prevalence of moderate and severe femoral anteversion in unilateral Legg-Calvé-Perthes disease

PurposeTo determine and stratify femoral version in Legg-Calvé-Perthes disease (LCPD), and to compare the femoral version between the LCPD hip and the contralateral unaffected hip.MethodsWe performed a retrospective review of 45 patients with unilateral LCPD who had available CT scan through the hips and knees between January 2000 and June 2017. There were 34 (76%) male cases with a mean age of 14 years (sd 4.69). Two independent readers measured femoral version on the affected and the unaffected contralateral femur. Femoral version was classified as follows: severely decreased version (< 10°); moderately decreased (10° to 14°); normal femoral version range (15° to 20°); moderately increased (21° to 25°); and severely increased version (> 25°).ResultsLCPD hips had predominantly increased femoral version (38% severely increased anteversion, 24% moderately increased anteversion), while 51% of the contralateral unaffected hips had normal femoral version (p < 0.001). LCPD hips had higher mean femoral version than the contralateral, unaffected side (mean difference = 13^o; 95% confidence iterval 10^o to 16^o; p < 0.001). As the version of the affected hip increased, so did the discrepancy between sides. No effect of sex on the LCPD femoral version was detected (p = 0.34).ConclusionThis study included a selected group of patients with unilateral LCPD and available CT scans obtained for surgical planning. The femoral version was asymmetric, with a high proportion of excessive anteversion observed at later stages of disease in the affected hips. Future studies will be necessary to determine the pathogenesis of increased femoral version associated with LCPD.Level of EvidenceLevel IV, retrospective study.     

Anteversion Angle Measurement in Suspected Torsional Malalignment of the Femur in 3-Dimensional EOS vs Computed Tomography—A Validation Study

BackgroundComputed tomography (CT) scan is the standard for assessment of femoral torsion. This observational study was conducted to evaluate the comparability of the EOS radiation dose scanning system (EOS imaging, Paris, France) and the CT scan in patients with suspected torsional malalignment of the femur.MethodsPatients with suspected torsional malalignment of the femur were included in a study for surgical planning. The primary endpoint was to compare the 3-dimensional radiological (EOS) imaging system with the CT scan to determine femoral anteversion (AV) angle. Three independent raters performed measurements. Comparability of CT scan and EOS values was assessed by Pearson correlation, t test, interobserver reliability, and intraobserver reliability (Cronbach alpha).ResultsAbout 34 femora were examined. Interobserver reliability/intraobserver reliability was 0.911 of 0.955 for EOS and 0.934 of 0.934 for CT scan. EOS system revealed an AV angle of 12.2° ± 10.0° (?15.0° to 32.0°). CT examinations showed an AV angle of 12.6° ± 9.2° (?3.2° to 35.6°). About 11 hips featured physiological AV, 14 hips showed decreased AV (<10°) or retroversion (<0°), and 9 hips showed increased AV (>20°). Overall, a strong Pearson correlation of τ = 0.855 and a highly significant correlation in the t test for both methods was seen. In patients with decreased AV, retroversion, or increased AV, Pearson correlation only resulted in a moderate/low correlation of τ = 0.495 and τ = 0.292. The t test showed no significant correlation at malrotation.ConclusionIn torsional malalignment, EOS does not have correlation with CT measurements. In contrast to CT scan, EOS allows femoral torsion measurement independent of legs' positioning.     

Deformities of proximal femur in spastic hip displacement: A reconstructed three-dimensional computed tomography model approach

Background/PurposeSpastic hip displacement is a common musculoskeletal problem in cerebral palsy (CP), leading to further complications in daily life. Deformities of the proximal femur were regarded as a factor in hip displacement, and therefore, femoral osteotomy is often recommended. This study aims to identify the relationship between hip displacement and femoral deformities.MethodsWe retrospectively collected preoperative radiography and three-dimensional computed tomography (3D-CT) images from 19 nonambulatory CP children with unilateral hip displacement (average age: 8.4 years; range: 4.4–13.6). The 3D image of femur was reconstructed for measuring the femur anteversion angle (FAA) and true femoral neck-shaft angle (NSA). The association among migration percentage (MP), acetabular index (AI), FAA, and NSA between nondisplaced and displaced hips was analyzed by paired t test and its correlations were identified.ResultsThe FAA and AI are significantly greater in displaced hips (42.7° vs. 36.3° and 32.8° vs. 22.7°, respectively, p < 0.001). However, the NSA is similar between displaced and nondisplaced hips. The AI and FAA have significantly positive correlations with MP between nondisplaced hips and displaced hips (0.69 and 0.57, respectively).ConclusionUsing reconstructed 3D-CT images we can directly measure and prove these femoral deformities. We found that AI has a positive correlation with MP (0.69), which is consistent with the results of previous studies. The displaced side has greater femur anteversion (42.7° vs. 36.3°), and coxa valga is common in these nonambulatory patients, irrespective of whether or not these patients underwent hip displacement. In addition, the severity of AI and anteversion angle will be affected by the MP.     

Trans-lateral decubitus radiograph of the hip: A new view to measure the anteversion of the femoral stem

BackgroundMalposition of the femoral stem is a risk factor for dislocation after total hip arthroplasty (THA). Currently, two radiological methods are available for the measurement of stem anteversion. However, one method is not applicable in patients with a stiff hip, and the other one cannot differentiate the anteversion and retroversion of the stem. Therefore, we developed a method to measure the stem anteversion and assessed its reliability as well as validity.MethodsTrans-lateral decubitus view of the proximal femur was taken with the patient in lateral decubitus position, the hip in extension and the knee in 90° flexion. Hip anteroposterior (AP) view, trans-lateral decubitus view and CT scan of the hip were taken in 36 patients, who underwent THA. Their mean age was 59.8 (27–84) years and the mean body mass index was 25.2 (18.8–30.9) kg/m². The stem neck-femoral shaft angle was measured on hip AP view and the trans-lateral decubitus view. Then, the stem anteversion was calculated using the Ogata-Goldsand formula. We assessed the intra- and inter-observer reliabilities and evaluated the validity by comparing with the measurements on CT scan.ResultsThe intra- and inter-observer reliabilities were 0.934 and 0.935, respectively. The calculated stem anteversion (23.72°±8.17°) correlated well with the stem anteversion on CT scan (23.91°±10.25°), especially when the radiological anteversion was <30° (correlation coefficient = 0.729, p = 0.001).ConclusionWe developed a reliable and valid method to measure stem anteversion using hip AP view and trans-lateral decubitus view of the femur. This method can replace conventional radiological methods.     

Evaluation of the accuracy of acetabular cup orientation using the accelerometer-based portable navigation system

BackgroundAccurate orientation of acetabular and femoral components is important during total hip arthroplasty (THA). In recent years, several navigation systems have been developed. However, these navigation systems for THA are unpopular worldwide because of their high cost. We assessed the orientation accuracy of cups inserted using a disposable accelerometer-based portable navigation system for THAs.MethodsThis was a prospective cohort study. We analyzed 63 hips with navigation prospectively and 30 hips without navigation retrospectively as historical control. The patients underwent THA via the mini anterolateral approach in the supine position using an accelerometer-based portable navigation system. We compared the preoperative target angles, intraoperative cup angles using navigation records, postoperative angles using postoperative CT data, measurement errors of cup angles, and clinical parameters such as sex, treated side, age at surgery, and body mass index (BMI).ResultsThe average absolute error (postoperative CT-navigation record) was 2.7 ± 2.1° (inclination) and 2.7 ± 1.8° (anteversion), and the absolute error (postoperative CT-preoperative target angle) was 2.6 ± 1.9° (inclination) and 2.7 ± 2.2° (anteversion). The absolute error between postoperative CT and target angle with navigation was significantly lower than the error without navigation (inclination; p = 0.025, anteversion; p = 0.005). Cup malalignment (absolute difference of inclination or anteversion between postoperative CT and preoperative target angle of over 5°) was significantly associated with BMI value (OR: 1.3, 95% CI: 1.1–1.7). The absolute measurement error of cup inclination and anteversion was significantly correlated with patients’ BMI (inclination error: correlation coefficient = 0.53, p < 0.001, anteversion error: correlation coefficient = 0.58, p < 0.001).ConclusionsThe clinical accuracy of accelerometer-based portable navigation is precise for the orientation of cup placement, although accurate cup placement was affected by high BMI. This is the first study to report the accuracy of accelerometer-based portable navigation for THA in the supine position.     

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

Background

To determine the interobserver agreement on femoral version measurements between an orthopedic attending, orthopedic senior and junior residents, and an attending radiologist.

Materials and methods

Postoperative 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.

Results

Version 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.

Conclusion

Regardless 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 evidence

Level III, diagnostic study.     

Assessment of Acetabular Component Anteversion after Total Hip Arthroplasty: Comparison of Anteroposterior and Cross-Table Lateral Radiographs with Computed Tomography Scans

BackgroundSeveral methods of measurement of anteversion of acetabular components after total hip arthroplasty (THA) have been described in the literature using plain radiographs or computed tomography (CT) scans. None of these have proved to be the gold standard. We aimed to study the correlation between the CT and radiographic methods of calculation of acetabulum anteversion.MethodsCT scans of the pelvis, anteroposterior (AP) and cross-table lateral (CL) radiographs were obtained in 60 patients who underwent THA two weeks after surgery. Anteversion was measured using Widmer method and Liaw method on AP radiographs, and the ischiolateral method on CL radiographs. Anteversion measured on the CT scan was taken as the reference anteversion and the above measurements were analysed for correlation with the measurements on CT scan. Intraclass correlation coefficients (ICCs) were calculated for both intra- and interobserver reliability.ResultsMean acetabular version on CL radiographs was 53.1 ± 10.7. Mean version on AP radiographs by Widmer method was 21.4 ± 3.6 and by Liaw method was 20.3 ± 4.8. Mean version on CT scans was 26.02 ± 6.8. There was a good correlation between the acetabular version on CT scans with the version on AP radiographs by Widmer method (r = 0.78, p < 0.001) and Liaw method (r = 0.87, p < 0.001). Good correlation was seen between the acetabular version on CL radiographs and CT scans (r = 0.91, p < 0.001). Also, a good correlation was observed between the acetabular version measurements on CL radiographs and AP radiographs by Widmer method (r = 0.81, p < 0.001) or Liaw method (r = 0.70, p < 0.001). Excellent inter- and intraobserver reliability were seen for all the measurements.ConclusionsCalculation of acetabular component version on AP views as well as CL views of plain radiographs showed a strong correlation with the version measurements on CT scans. Good correlations were observed between different techniques of measurement on radiographs. Therefore, all these measurements can be valid methods for assessment of anteversion.     

应用双髋关节正位X线片评估全髋关节置换术后髋臼前倾角

目的: 探讨是否可以在普通双髋关节正位X线片上评估髋臼假体前倾角。方法: 2019年3月至7月收治全髋关节置换术后患者32例(共41髋),男18例,女14例,年龄(66.2±4.1)岁,所有患者于术后完成双髋关节正位X线片及骨盆CT平扫。通过骨盆CT平扫测量髋臼前倾角,在X线片上采用Saka等测量公式进行测量。结果: 41髋X线片测量髋臼前倾角为(16.2±5.0)°,与CT测量的髋臼前倾角(31.8±9.7)°间差异有统计学意义(P=0.00)。此外,X线片测量与CT测量的髋臼前倾角具有明显相关性(Pearson相关系数r=0.84,P=0.00)。结论: CT可以较准确地测得髋臼前倾角,但是其存在辐射量大、成本较高、假体CT伪影重等明显弊端。在普通双髋关节正位X线片上采用Saka测量公式虽然无法像CT测量一样直接获得准确的髋臼前倾角,但却和CT测得的髋臼前倾角间存在高度的相关性,所以提出的方法也可以初步评估髋臼前倾角。     

A nonlinear QCT-based finite element model validation study for the human femur tested in two configurations in vitro

PurposeFemoral fracture is a common medical problem in osteoporotic individuals. Bone mineral density (BMD) is the gold standard measure to evaluate fracture risk in vivo. Quantitative computed tomography (QCT)-based homogenized voxel finite element (hvFE) models have been proved to be more accurate predictors of femoral strength than BMD by adding geometrical and material properties. The aim of this study was to evaluate the ability of hvFE models in predicting femoral stiffness, strength and failure location for a large number of pairs of human femora tested in two different loading scenarios.MethodsThirty-six pairs of femora were scanned with QCT and total proximal BMD and BMC were evaluated. For each pair, one femur was positioned in one-legged stance configuration (STANCE) and the other in a sideways configuration (SIDE). Nonlinear hvFE models were generated from QCT images by reproducing the same loading configurations imposed in the experiments. For experiments and models, the structural properties (stiffness and ultimate load), the failure location and the motion of the femoral head were computed and compared.ResultsIn both configurations, hvFE models predicted both stiffness (R² = 0.82 for STANCE and R² = 0.74 for SIDE) and femoral ultimate load (R² = 0.80 for STANCE and R² = 0.85 for SIDE) better than BMD and BMC. Moreover, the models predicted qualitatively well the failure location (66% of cases) and the motion of the femoral head.ConclusionsThe subject specific QCT-based nonlinear hvFE model cannot only predict femoral apparent mechanical properties better than densitometric measures, but can additionally provide useful qualitative information about failure location.     

Lower limb malrotation following MIPO technique of distal femoral and proximal tibial fractures

Objective

To determine the incidence of rotational malalignment in distal femoral and proximal tibial fractures using computed tomography (CT) scanograms following indirect reduction and internal fixation with the minimally invasive percutaneous osteosynthesis (MIPO) technique.

Design

Prospective Cohort.

Setting

Level I Trauma Centre.

Patients/Participants

A total of 27 consecutive subjects, and 14 proximal tibia and distal femur fractures.

Intervention

All patients underwent indirect reduction and internal fixation with a MIPO plating system. A CT scanogram to measure rotational malalignment between the injured and non-injured extremity was then undertaken.

Main outcome measure(s)

Femoral anteversion angles and tibial rotation angles between the injured and non-injured extremities were compared. Malrotation was defined as a side-to-side difference of >10°.

Results

A total of 14 postoperative tibias and 13 femurs underwent CT scanograms. Three females and 11 males with an average age of 38.1 years sustained proximal tibia fractures and six females and seven males with an average age of 55.8 years sustained distal femur fractures. The difference between tibial rotation in the injured and the non-injured limbs ranged from 2.7 to 40.0° with a mean difference of 16.2° (p = 0.656, paired T-test). Fifty percent of the tibias fixed with MIPO plates were malrotated >10° from the uninjured limbs. The difference between femoral anteversion in the injured and non-injured limbs ranged from 2.0 to 31.3° with a mean difference of 11.5° (p = 0.005, paired T-test). A total of 38.5% of the distal femurs fixed with MIPO plates were malrotated >10° from the uninjured limb.

Conclusions

Following fixation of distal femoral and proximal tibial fractures, the incidence of malrotation was 38.5% and 50%, respectively. The difference of the mean measures was significant for femoral malrotation; however, statistical significance could not be demonstrated for tibial malrotation. The incidence of malrotation following MIPO plating in this study is much higher than that quoted in previous studies.     

Factors associated with acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time lateral patellar dislocation: A prospective magnetic resonance imaging study

ObjectivesTo identify risk factors of acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time lateral patellar dislocation (LPD).MethodsMagnetic resonance images were prospectively analyzed in 115 patients in an acute first-time LPD. Factors included gender, skeletal maturity, trochlear dysplasia, patellar height, and tibial tuberosity–trochlear groove (TT-TG) distance. Binary logistic regression analysis was carried out to identify the independent risk factors for the incidence of acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time LPD.ResultsThe incidence of acute articular cartilage lesion of the patella and lateral femoral condyle were 46.1% and 27% in acute first-time LPD, respectively. Univariate analysis revealed significantly higher incidence rate of acute articular cartilage lesion of the patella in male (P = 0.027), skeletally mature (P = 0.035), normal TT-TG distance (P = 0.043) and normal femoral trochlea (P = 0.031). Risk factors for the incidence of acute articular cartilage lesion of the patella were skeletally mature (odds ratio (OR): 2.324), normal TT-TG distance (OR: 2.824) and normal femoral trochlea (OR: 3.835). Univariate analysis revealed significantly higher incidence rate of acute articular cartilage lesion of the lateral femoral condyle in skeletally mature (P = 0.027) and normal femoral trochlea (P = 0.031). Risk factor for the incidence of acute articular cartilage lesion of the lateral femoral condyle was normal femoral trochlea (OR: 3.347).ConclusionsFor patients in acute first-time LPD, compared with other parameters, the normal femoral trochlea, normal TT-TG distance and skeletally mature are independent risk factors for the incidence of acute articular cartilage lesion of the patella, and the normal femoral trochlea is an independent risk factor for the incidence of acute articular cartilage lesion of the lateral femoral condyle.     

Lesser Trochanter Size on Plain Anteroposterior Radiographs Correlates With Native Femoral Anteversion

Background

Assessing femoral version in orthopedic surgery is important for preoperative planning of total hip arthroplasty, especially for recognizing excessive anteversion or retroversion. The present study addressed the following: (1) Is the position of the lesser trochanter correlated to the femoral neck axis? (2) If so, may femoral version be assessed by means of plain pelvic radiographs?

Flat foot and femoral anteversion in children—A prospective study

BackgroundFlat foot in children during the first years of life evokes significant parental concern. Flat foot, intoeing and femoral anteversion may well be differential dimensions of developmental pathodynamics with potential for inter-related developmental correction. While correlation of femoral anteversion with intoeing is documented, its relationship with flat foot remains unclear.ObjectiveThe aim of this prospective study is to investigate the relationship between flat foot and internal rotation of hip, indirectly femoral anteversion.Methods651 Children, 339 boys and 312 girls, aged 3–6 years, were examined and Contact Index II for flat foot as well as internal rotation of hip measured. 82 children with other foot and leg deformities were excluded from further analysis.ResultsOut of 569 children, 95 (16.7%) had flat feet – 56 bilateral, 39 unilateral – with Contact Index II of 0.88 or above. All children with flat feet (and none of the normal 474) had raised internal rotation of hip (mean 69.9°, range 62–80°).ConclusionRegression analysis established an unequivocal and highly significant statistical relationship between flat foot and increased internal rotation of hip (F = 168.1, p < 0.001, r = 0.53) in children between 3 and 6 years.     

液晶数字显示角度仪在全髋关节置换术中的应用价值

目的:探讨在全髋关节置换术中使用液晶数字显示角度仪控制前倾角的应用价值。方法:回顾分析自2018年1月至2019年12月83例行初次全髋关节置换术的患者,其中男28例,女55例;年龄42~81(70.4±7.9)岁。股骨颈骨折63例,股骨头缺血性坏死20例。所有患者术中使用液晶数显角度仪控制髋臼杯假体的前倾角,术后采用CT扫描,测量髋臼杯的前倾角,两者进行比较,了解使用液晶数显角度仪的准确性。结果:术后CT测量提示患者的髋臼前倾角均位于Lewinnek提倡的安全区内,术中使用液晶数显角度仪测量髋臼杯的前倾角度中位数为14.20°(12.80~15.40)°,术后CT扫描测量的髋臼杯的前倾角中位数为14.20°(13.40~15.50)°,两者比较差异无统计学意义(Z=-1.725,P=0.085)。结论:应用液晶数显角仪器对术中控制髋臼杯的前倾角是一种准确可靠的方法,具有良好的辅助参考价值。     

Tibial Tubercle-Trochlear Groove Distance Influences Patellar Tilt After Total Knee Arthroplasty

BackgroundTibial tubercle-trochlear groove (TT-TG) distance is associated with a greater risk of recurrent patellar dislocation in young, active patients. However, the effect of TT-TG distance after total knee arthroplasty (TKA) has not been investigated. The purpose is to analyze the effect of TT-TG distance and component rotation on patellar tilt and patellar shift after TKA.MethodsAfter TKA, axial computed tomography scans and axial radiograph were taken in 115 consecutive knees. TT-TG distance was measured between the most anterior point of the tibial tuberosity and the deepest point of the femoral component relative to a line connecting the anterior condyles. Femoral and tibial component rotation was measured relative to the femoral and tibial rotational axis, respectively. Pearson correlation coefficients were calculated.ResultsTT-TG distance had a significant correlation with patellar tilt in extension (R = 0.220, P = .018), patellar tilt in flexion (R = 0.438, P < .001), and patellar shift (R = 0.330, P < .001). Tibial component rotation had a significant correlation with patellar tilt in flexion (R = −0.251, P = .007) and patellar shift (R = −0.360, P < .001). Femoral component rotation had no significant correlations. Tibial component rotation had a significant correlation with TT-TG distance (R = −0.573, P < .001), whereas femoral component rotation had no correlation (P = .192).ConclusionTT-TG distance had a significant correlation with patellar tilt and patellar shift. Surgeons need to understand the factors affecting TT-TG distance and to pay attention to avoiding excessive TT-TG distance after TKA.     

Trochanteric entry femoral nails yield better femoral version and lower revision rates—A large cohort multivariate regression analysis

IntroductionIntramedullary nailing (IMN) has become the standard of care for the treatment of most femoral shaft fractures. Different IMN options include trochanteric and piriformis entry as well as retrograde nails, which may result in varying degrees of femoral rotation. The objective of this study was to analyze postoperative femoral version between three types of nails and to delineate any significant differences in femoral version (DFV) and revision rates.Materials & methodsOver a 10-year period, 417 patients underwent IMN of a diaphyseal femur fracture (AO/OTA 32A-C). Of these patients, 316 met inclusion criteria and obtained postoperative computed tomography (CT) scanograms to calculate femoral version and were thus included in the study. In this study, our main outcome measure was the difference in femoral version (DFV) between the uninjured limb and the injured limb. The effect of the following variables on DFV and revision rates were determined via univariate, multivariate, and ordinal regression analyses: gender, age, BMI, ethnicity, mechanism of injury, operative side, open fracture, and table type/position. Statistical significance was set at p < 0.05.ResultsA total of 316 patients were included. Piriformis entry nails made up the majority (n = 141), followed by retrograde (n = 108), then trochanteric entry nails (n = 67). Univariate regression analysis revealed that a lower BMI was significantly associated with a lower DFV (p = 0.006). Controlling for possible covariables, multivariate analysis yielded a significantly lower DFV for trochanteric entry nails than piriformis or retrograde nails (7.9 ± 6.10 vs. 9.5 ± 7.4 vs. 9.4 ± 7.8°, p < 0.05). Using revision as an endpoint, trochanteric entry nails also had a significantly lower revision rate, even when controlling for all other variables (p < 0.05).ConclusionComparative, objective comparisons between DFV between different nails based on entry point revealed that trochanteric nails had a significantly lower DFV and a lower revision rate, even after regression analysis. However, this is not to state that the other nail types exhibited abnormal DFV. Translation to the clinical impact of a few degrees of DFV is also unknown. Future studies to more in-depth study the intricacies of femoral version may lead to improved technology in addition to potentially improved clinical outcomes.     

Does It Matter: Total Hip Arthroplasty or Lumbar Spinal Fusion First? Preoperative Sagittal Spinopelvic Measurements Guide Patient-Specific Surgical Strategies in Patients Requiring Both

BackgroundIn patients requiring both total hip arthroplasty (THA) and lumbar spinal fusion (LSF), consideration of preoperative sagittal spinopelvic measurements can aid in the prediction of postfusion compensatory changes in pelvic tilt (PT) and inform adjustments to traditional THA cup anteversion. This study aims to identify relationships between spinopelvic measurements and post-THA hip instability and to determine if procedure order reveals a difference in hip dislocation rate.MethodsPatients at a single practice site who received both THA and LSF between 2005 and 2015 (292: 158 = LSF prior to THA, 134 = THA prior to LSF) were retrospectively reviewed for incidents of THA instability. Those with complete radiograph series (89) had their sagittal (standing) spinopelvic profiles measured preoperatively, immediately postoperatively, and 3 months, 6 months, 1 year, 1.5 years, and 2 years postoperatively. Measured parameters included lumbar lordosis (LL), pelvic incidence (PI), PT, and sacral slope (SS).ResultsNo significant differences in dislocation rates between operative order groups were elicited (7/73 LSF first, 4/62 THA first; Z = 0.664, P = .509). Compared to nondislocators, dislocators had lower LL (−10.9) and SS (−7.8), and higher PT (+4.3) and PI-LL (+7.3). Additional risk factors for dislocation included sacral fusion (relative risk [RR] = 3.0) and revision fusion (RR = 2.7) . Predictive power of the model generated through multiple regression to characterize individual profiles of post-LSF PT compensation based on perioperative measurements was most significant at 1 year (R² = 0.565, F = 0.000456, P = .028) and 2 years (R² = 0.741, F = 0.031, P = .001) postoperatively.ConclusionIn performing THA after LSF, it is theoretically ideal to proceed with THA at a postfusion interval of at least 1 year, beyond which further compensatory PT change is minimal. However, the order of surgical procedure revealed no statistical difference in hip instability rates. In cases characterized by large PI-LL mismatch (larger or less predictable compensation profiles) or large SS or LL loss (considerably atypical muscle recruitment), consideration of full functional anteversion range between sitting and standing positions to account for abnormalities not appreciated with standing radiographic assessment alone may be warranted.     

3D打印技术测量儿童发育性髋关节脱位股骨颈前倾角

目的:探讨利用3D打印技术测量发育性髋关节脱位儿童股骨颈前倾角的方法及准确性以期找到准确测量该类患儿股骨颈前倾角的方法并指导制定手术方案。方法:纳入2016年6月至2018年9月需行手术治疗的单侧发育性髋关节脱位患者17例,男2例,女15例;年龄2～13(5.47±0.81)岁;左侧11例,右侧6例。用CT测量法(CT法)、3D打印的股骨实物模型测量法(模型法)和术中股骨颈前倾角测量法(术中法)分别测量患儿股骨颈前倾角,以术中法测量值作为标准参考值,进行统计学分析,比较前两种测量方法的准确性。结果:CT法测量平均值为(36.00±1.66)°,模型法测量平均值为(43.91±1.62)°,术中法测得股骨前倾角平均值为(44.21±1.62)°。CT法测量值与模型法测量值、术中法测量值的比较差异均有统计学意义(P0.05)。模型法测量值与术中法测量值差异无统计学意义(P0.05)。结论:利用3D打印技术的模型法测量儿童发育性髋关节脱位股骨颈前倾角与传统CT测量法相比更简单、准确、可重复性强,而且可以术前模拟术中操作,是目前比较理想的测量股骨颈前倾角的方法。