Optimizing post-operative imaging: a retrospective cohort study comparing two methods of lateral hip radiography after cephalomedullary nail surgery.

BACKGROUND: Currently, there is no consensus on the most appropriate technique for obtaining lateral hip radiographs after cephalomedullary nail (CMN) surgery. The aim of this study was to investigate the distribution of two commonly used postoperative lateral hip radiographic methods (classic lateral view and modified lateral view) and try to find out which one is better suited for this situation. METHODS: A retrospective analysis was conducted on 146 patients who underwent surgical fixation for extracapsular hip fractures between January 2018 and June 2022. The main outcome measured was the angle between the straight part of the CMN and the lag screw/blade on hip lateral X-rays (CMNA). The lateral hip radiographs were categorized into two groups based on different lateral hip radiographic methods. CMNA, patient age, gender, fracture classification based on the 2018 AO classification, nail length (short/long), surgical side (left/right), height, weight, BMI, preoperative waiting time, postoperative imaging interval were collected and compared between the two groups. RESULTS: The distribution trend of CMNA significantly differs between two types of hip joint lateral radiographic methods. Specifically, the classic lateral method exhibits a significantly bimodal and skewed distribution with a median (p25, p75) of -21.6° (-31.2°, -8°), whereas the modified lateral method presents a normal distribution with a mean ± SD of +7.57° ± 14.4°. The difference in the Mean Rank between the classic (47.10) and the modified (102.96) lateral methods is statistically significant (P < 0.001). CONCLUSIONS: The CMNA method is an excellent tool for studying the lateral distribution.We recommend using the modified lateral view as the preferred option for obtaining lateral hip radiographs after CMN surgery due to its superior distribution of CMNA and greater patient-friendliness.

Correlation of the Lateral Wrist Radiograph to Ulnar Variance: A Cadaveric Study.

PURPOSE: Both positive and negative ulnar variance have been implicated in a variety of wrist disorders. Surgery aims to correct the variance in these pathologic conditions. This necessitates accurate and reproducible measuring tools; however, the most accurate radiographic measurement technique remains unclear. The purposes of this study were to evaluate 3 methods for determining ulnar variance and to compare each with direct anatomic measurement in a cadaver model. METHODS: We fixed 10 fresh above-elbow cadaver specimens in neutral rotation and obtained standardized fluoroscopic posteroanterior and lateral wrist images. A dorsal approach was performed and two independent investigators directly measured ulnar variance using digital calipers with the cartilage both intact and denuded. Ulnar variance was measured radiographically using the lateral, perpendicular, and central reference point methods. The reliability of each set of measurements (within a 1-mm cutoff) was assessed by the intraclass coefficient; agreement between radiographic and direct measurements was evaluated by the Bland-Altman method. RESULTS: Each method of determining ulnar variance demonstrated near perfect agreement by the intraclass coefficient. The lateral radiograph method correlated highly with the directly measured ulnar variance with the cartilage denuded with an average measurement difference of 0.06 mm. No radiographic measurement technique demonstrated consistent agreement within 1 mm of the measured ulnar variance with the cartilage intact. CONCLUSIONS: Ulnar variance measured by the lateral wrist radiograph technique correlates highly with the directly measured osseous ulnar variance. The remaining measurement techniques did not correlate reliably to within 1 mm of the directly measured ulnar variance with 95% confidence. No method was able to account accurately for the articular cartilage thicknesses at the lunate facet of the radius or the distal ulnar head, which we found to vary in an unpredictable manner. Whereas the lateral radiograph has been shown to allow for more reliable standardization of wrist position compared with the posteroanterior view, this study also highlights the inherent limitations of using static radiographic images in evaluating ulnar variance. CLINICAL RELEVANCE: The results of the current study demonstrate the utility of the lateral wrist radiograph for assessing bony ulnar variance.

Variations in sagittal locations of anterior cruciate ligament tibial footprints and their association with radiographic landmarks: a human cadaveric study.

BACKGROUND: This cadaveric study aimed to demonstrate variation of the anterior cruciate ligament (ACL) tibial attachment in the sagittal plane, and to analyze the radiographic landmarks which predict the sagittal location of the ACL tibial attachment. METHODS: In 20 cadaveric knees, native ACLs were removed and the centers of the ACL tibial and femoral attachments were marked with metal pins. Full extension lateral radiographs were then obtained in each cadaveric knee. Using the full extension lateral radiographs, the sagittal location of the ACL tibial footprint center was estimated as a percentage in the Amis and Jakob's line. Several radiographic landmarks including the geometry of Blumensaat's line and the apex of the tibial eminence were measured. Then, the relationship between the variation of the sagittal location of the ACL tibial footprint and several radiographic landmarks were analyzed using Pearson's correlation analysis. RESULTS: The average sagittal position of the native ACL tibial footprint was 40.9% (range: 38.0-45.0%). The line connecting the centers of the ACL footprint was nearly parallel to Blumensaat's line, with an average angle of 1.7° (range: 0-4.1°). In addition, the distance from the point where Blumensaat's line meets the tibial articular surface to the center of the ACL tibial footprint was almost consistent, at 7.6 mm on average (range: 6.4-8.7 mm). The correlation analysis revealed that the geometry of Blumensaat's line was significantly correlated with the sagittal location of the ACL tibial footprint. CONCLUSION: The radiographic landmark that showed a significant correlation with the ACL tibial footprint in the full extension lateral radiographs was Blumensaat's line.

Lateral X-ray for proximal femoral fractures - Is it really necessary?

INTRODUCTION: Historically routine work up of a patient with a proximal femoral fracture always included anterior-posterior (AP) and a lateral film of the hip. The aim was to define the role of the lateral X-ray in the assessment and surgical planning of proximal femur fractures. METHODS: Radiographs of 320 consecutive patients with proximal femoral fractures who were admitted over a 12 months period were divided into lateral and AP views. Two blinded reviewers independently assessed the AP view alone and then the AP plus the lateral view. Fracture classification was noted for each X-ray and then compared with intraoperative diagnosis which was our study's gold standard. A 2 × 2 contingency square table and Pearson's x(2) test were used for statistical analysis. RESULTS: The rate of correct classification by the reviewers enhanced by the assessment of the lateral X-ray in addition to the AP view for intracapsular fractures (p = 0.018) but not for extracapsular fractures (p = 0.29). Operative management did not change for intracapsular fractures which appeared displaced on initial AP view after reviewing the lateral X-ray. The only advantage of obtaining a lateral view in intracapsular fracture was the detection of displacement were the fracture appeared to be undisplaced on initial AP view. CONCLUSIONS: This study provides statistical evidence that one view is adequate and safe for majority of proximal femoral fractures. The lateral radiograph should not be performed on a routine basis thus making considerable saving in time and money, and avoiding unnecessary radiation exposure and discomfort to the patient.

Is a Stem Version on the Crosstable Lateral Radiograph Accurate in Total Hip Arthroplasty?

BACKGROUND: In contrast to the acetabular cup version (CV), stem version (SV) measurement on the crosstable lateral radiograph has not been validated. We, therefore, investigated: (1) the difference of SV on the crosstable lateral radiograph from that measured using computed tomography data and (2) the reliability of SV measurement on the crosstable lateral radiograph. METHODS: We examined the correlations of the crosstable-CV and crosstable-SV with true-CV (operative cup anteversion) and true-SV (neck version relative to the posterior condylar line) obtained using computed tomography data from 103 patients. We also produced the digital reconstructed crosstable lateral radiograph with adjusted hip flexion and rotation and defined SV on this image as the true-crosstable SV. RESULTS: Significant positive correlations were noted between the crosstable-CV and true-CV, with a correlation coefficient of 0.79. In contrast, the correlation between the crosstable-SV and true-SV was very low (r = 0.30), with significantly higher deviation from the true-SV values when compared with the crosstable-CV (standard deviation, 11.6° vs 6.5°, P < .001). The true-crosstable SV was correlated with true-SV (r = 0.81); however, the average difference was 23.5° ± 8.9°. CONCLUSION: Crosstable-SV differed from true-SV in the measurement plane and did not correlate well with the true-SV, suggesting the unreliability of its measurements. Therefore, the crosstable-SV is not recommended for clinical use.

Sagittal Full-Spine vs. Sectional Cervical Lateral Radiographs: Are the Measurements of Cervical Alignment Interchangeable?

(1) Background: This study assessed the relationship between cervical spine parameters taken on standing full-spine lateral radiographic images compared to sectional lateral cervical radiographs. (2) Methods: Full-spine (FS) and sectional lateral cervical (LC) radiographs from four spine treatment facilities across the USA retrospectively provided data collected on 220 persons to assess the comparison of three sagittal cervical radiographic measurements between the two views. The measures included cervical lordosis using the absolute rotation angle from C2-C7, sagittal cervical translation of C2-C7, and atlas plane angle to horizontal. Linear correlation and R2 models were used for statistical comparison of the measures for the two views. (3) Results: The mean values of the three measurements were statistically different from each other: C2-C7 translation (FS = 19.84 ± 11.98 vs. LC = 21.18 ± 11.8), C2-C7 lordosis (FS = -15.3 ± 14.63 vs. LC = -18.32 ± 13.16), and atlas plane (FS = -19.99 ± 8.88 vs. LC = -22.56 ± 8.93), where all values were p < 0.001. Weak-to-moderate-to-strong correlations existed between the full-spine and sectional lateral cervical radiographic variables. The R2 values varied based on the measurement were R2 = 0.768 (p < 0.001) for sagittal cervical translation of C2-C7 (strong), R2 = 0.613 (p < 0.001) for the absolute rotation angle C2-C7 (moderate), and R2 = 0.406 (p < 0.001) for the atlas plane line (weak). Though a linear correlation was identified, there were consistent intra-person differences between the measurements on the full spine versus sectional lateral cervical radiographic views, where the full-spine view consistently underestimated the magnitude of the variables. (4) Conclusion: Key sagittal cervical radiographic measurements on the full spine versus sectional lateral cervical radiographic views show striking intra-person differences. The findings of this study confirm that full spine versus sectional lateral cervical radiographic views provide different biomechanical magnitudes of cervical sagittal alignment, and caution should be exercised by health care providers as these are not interchangeable. We recommend the LC view for measurement of cervical sagittal alignment variables.

Resolution of Sporadic Hemiplegic Migraine by Correcting a Cervical Spine Kyphosis Utilizing the Chiropractic BioPhysics® (CBP®) Technique: A Case Report With Long-Term Follow-Up.

A 19-year-old male suffered from sporadic hemiplegic migraine (SHM) for several years and experienced significant pain and disability with sensory and motor disturbances during the migraine headaches. Weakness, abnormal vision, abnormal sensation, one-sided disabling motor weakness, and other signs of SHM were diagnosed. The patient had received previous physical therapy, chiropractic and over-the-counter medications, as well as migraine-specific prescriptions without lasting improvements. Chiropractic BioPhysics® (CBP®) spinal structural rehabilitation protocols were used to increase cervical lordosis and improve cervical muscular strength, mobility, and posture. These protocols include spine-specific prescriptions for Mirror Image® postural exercises, traction, and spinal manipulative therapy. After 24 treatments over eight weeks, all subjective and objective outcomes improved dramatically with a near resolution of all initial symptoms of SHM. There were a significant increase in cervical lordosis and a reduction in forward head posture. The neck disability index improved from 26% to 6%, and all pain scores for all regions improved following treatment. A 10-month follow-up exam showed the outcomes were maintained. SHM is rare and debilitating, is part of the global burden of disease, and is a major cause of disability in the world. Reports of successful conservative and non-conservative long-term treatments for SHM are rare, and there are no clinical trials showing successful treatments for SHM. This successful case demonstrates preliminary evidence that CBP spinal structural rehabilitation may serve as a treatment option for SHM. Future studies are needed to replicate the findings from this case.

Abnormal Static Sagittal Cervical Curvatures following Motor Vehicle Collisions: A Retrospective Case Series of 41 Patients before and after a Crash Exposure.

Previous investigations have found a correlation between abnormal curvatures and a variety of patient complaints such as cervical pain and disability. However, no study has shown that loss of the cervical curve is a direct result of exposure to a motor vehicle collision (MVC). This investigation presents a retrospective consecutive case series of patients with both a pre-injury cervical lateral radiograph (CLR) and a post-injury CLR after exposure to an MVC. Computer analysis of digitized vertebral body corners on CLRs was performed to investigate the possible alterations in the geometric alignment of the sagittal cervical curve. METHODS: Three spine clinic records were reviewed over a 2-year period, looking for patients where both an initial lateral cervical X-ray and an examination were performed prior to the patient being exposed to a MVC; afterwards, an additional exam and radiographic analysis were obtained. A total of 41 patients met the inclusion criteria. Examination records of pain intensity on numerical pain rating scores (NPRS) and neck disability index (NDI), if available, were analyzed. The CLRs were digitized and modeled in the sagittal plane using curve fitting and the least squares error approach. Radiographic variables included total cervical curve (ARA C2-C7), Chamberlain's line to horizontal (skull flexion), horizontal translation of C2 relative to C7, segmental translations (retrolisthesis and anterolisthesis), and circular modelling radii. RESULTS: There were 15 males and 26 females with an age range of 8-65 years. Most participants were drivers (28) involved in rear-end impacts (30). The pre-injury NPRS was 2.7 while the post injury was 5.0; p < 0.001. The NDI was available on 24/41 (58.5%) patients and increased after the MVC from 15.7% to 32.8%, p < 0.001. An altered cervical curvature was identified following exposure to MVC, characterized by an increase in the mean radius of curvature (265.5 vs. 555.5, p < 0.001) and an approximate 8° reduction of lordosis from C2-C7; p < 0.001. The mid-cervical spine (C3-C5) showed the greatest curve reduction with an averaged localized mild kyphosis at these levels. Four participants (10%) developed segmental translations that were just below the threshold of instability, segmental translations < 3.5 mm. CONCLUSIONS: The post-exposure MVC cervical curvature was characterized by an increase in radius of curvature, an approximate 8° reduction in C2-C7 lordosis, a mild kyphosis of the mid-cervical spine, and a slight increase in anterior translation of C2-C7 sagittal balance. The modelling result indicates that the post-MVC cervical sagittal alignment approximates a second-order buckling alignment, indicating a significant alteration in curve geometry. Future biomechanics experiments and clinical investigations are needed to confirm these findings.

Reliability and validity of the functional combined anteversion measurement method using standing lateral radiography after total hip arthroplasty.

Background: The functional safe zone of combined anteversion (CA) shows a superior predictive value for dislocation after total hip arthroplasty (THA) compared to that of the Lewinnek safe zone. Thus, it is necessary to establish a feasible and accurate method for assessing CA for the evaluation of dislocation risk. We aimed to evaluate the reliability and validity of using standing lateral (SL) radiographs for determining CA. Methods: Sixty-seven patients who underwent SL radiography and computed tomography (CT) scans after THA were included. Radiographic CA values were obtained via the calculation of the sum of the acetabular cup and femoral stem anteversion (FSA) measurements as obtained from the SL radiographs. Acetabular cup anteversion (AA) was measured based on the tangential line to the face of the cup, whereas FSA was calculated using the developed formula based on the neck-shaft angle. The intra-observer and inter-observer reliabilities for each measurement were examined. Radiological CA values were compared with the CT scan measurements to evaluate their validity. Results: The intra-observer and inter-observer agreements of the SL radiography were excellent [intraclass correlation coefficient (ICC) ≥0.90]. The radiographic measurements correlated well with the CT scan measurements (r=0.869, P<0.001). The mean difference between the radiographic and CT scan measurements was -0.55°±4.68° and ranged from 0.3° to 2.2° in terms of the 95% confidence interval (CI). Conclusions: SL radiography is a reliable and valid imaging tool for the assessment of functional CA.

Evaluation of the accuracy of new modalities in the assessment and classification of lumbar lordosis: A comparison to Cobb's angle measurement.

Background: Because of the association of lumbar lordosis with some clinical conditions such as low back pain, the chiropractic field has emphasized the significance of evaluating the lumbar lordotic status, by measuring Cobb's angle, regarded as the radiological gold standard, for the assessment of lumbar lordosis, on lateral radiographs. However, research has shown that this technique has some considerable drawbacks, mostly in terms of low accuracy and high variability between clinicians when compared with other radiological modalities. The main objective was to compare the diagnostic accuracy of newly established radiological measurements with one of Cobb's angle methods, for the characterization of lumbar lordosis status in a sample of Lebanese patients aged 15 and above. Material and methods: This retrospective single-center study consisted of measuring Cobb's L1-S1 and Cobb's L1-L5 angles, along with the novel established measurements which are the derivative and the normalized surface area, on 134 lateral radiographs of the lumbar spine of Lebanese patients aged fifteen years old and above, gotten from the Radiology department at Zahra'a's Hospital in Beirut, performed by two observers using MATLAB. Inter-rater agreement was assessed by calculating the Intra-class correlation coefficients. Spearman correlation was analyzed between both Cobb's angle methods and with the derivative and normalized area respectively. 54 patients of the sample were diagnosed by two radiologists, according to their LL status. ROC curve analysis was performed to compare the diagnostic accuracy of the four techniques used. Data were analyzed with IBM SPSS Statistics 23.0 (NY, USA); P < 0.05 was considered statistically significant. Results: According to the ROC curve analysis the new methods, which are the derivative and the normalized surface area, displayed lower diagnostic accuracy (AUCderivative = 0.818 and 0.677, AUCsurface area = 0.796 and 0.828) than Cobb's L1-L5 (AUCL1-L5 = 0.924 and 0.929 values) and L1-S1 (AUCL1-S1 = 0.971 and 0.955) angles, in the characterization of hypo and hyperlordotic patients, respectively, in our Lebanese sample consisting of patients aged 15 and above, because of their lower area under the curve's values compared to the traditional Cobb's techniques. The Cobb's L1-S1 has shown to have the highest diagnostic accuracy among the four methods to characterize normal patients from hypo and hyperlordotic ones, by referring to its highest area under the curve's values. However, the sensitivity of Cobb's L1-L5 angle in characterizing hyperlordotic patients was similar to the one of the normalized surface area with a value of 100%.Conclusion: among the four modalities, the new methods didn't show a better diagnostic accuracy compared to the traditional modalities. Cobb's L1-S1 displayed the highest diagnostic accuracy despite its drawbacks. Further prospective studies are needed to validate the cut-offs obtained for Cobb's L1-S1 angle in our sample.

Risk Factors for the Aggravation of Sagittal Balance After L5-S1 Posterior Lumbar Interbody Fusion.

OBJECTIVE: To identify the risk factors for the aggravation of sagittal alignment after single-level L5-S1 PLIF. METHODS: Eighty-six patients who underwent L5-S1 PLIF were divided into 2 groups according to the postoperative changes in the segmental angle (SA; group I: increase; group D: decrease). The 2 groups were compared in terms of demographic, clinical, and radiological outcomes. Multivariate logistic regression analysis was performed to identify the risk factors for aggravation of sagittal alignment. RESULTS: Of the study patients, 39 (45%) were categorized as group I and 47 (55%) as group D. The demographic and clinical parameters were not significantly different between the 2 groups. Group D showed postoperative deteriorations in the local sagittal parameters, including lumbar lordosis (LL; P = 0.034), sacral slope (P = 0.012), and pelvic tilt (P = 0.003). In contrast, group I showed improved LL after surgery (P = 0.021). Large preoperative values of lumbosacral angle (LSA; odds ratio [OR], 1.287; P = 0.001), SA (OR, 1.448; P < 0.001), and flexion LSA (OR, 1.173; P = 0.011) were independent risk factors for the aggravation of sagittal balance. CONCLUSIONS: Surgeons treating patients with large preoperative SA, LSA, and flexion LSA at L5-S1 level should be cautious of the possible aggravation of sagittal balance after L5-S1 PLIF and may consider different surgical approaches such as anterior or oblique lumbar interbody fusion.

Reliability and Validity of Standing Lateral Radiograph Method for Measuring Acetabular Component Version: A Modified Cross-table Lateral Radiograph Method.

OBJECTIVES: To investigate the effect of the X-ray incidence angle on cup version measurements and the reliability and validity of standing lateral (SL) radiography for measuring cup versions. METHODS: Cup versions under different X-ray incidence angles were investigated by the 3D simulation analysis. Ninety-three patients, who underwent primary total hip arthroplasty (THA) with postoperative SL radiographs and CT scans between April 2020 and December 2021, were retrospectively analyzed. SL radiography was taken under naturally standing position, correcting for the measurement error of pelvic tilt in cross-table lateral (CL) radiography. Cup versions were measured on SL radiographs and CT images by two qualified orthopedic physicians. The intra- and inter-observer reliabilities were assessed by intra-class correlation coefficient. The consistency between radiographic and CT measurements was evaluated using Pearson correlation coefficient. RESULTS: No significant differences in cup version measurements were observed between groups of different X-ray incidence angles (P = 0.663) in the 3D simulation analysis. All measurements had excellent intra- and inter-observer reliabilities, with an intraclass correlation coefficient of >0.95. Mean cup version measurements from SL radiographs correlated well with those from CT scans (r = 0.853, P < 0.001). The mean difference between radiographic and CT measurements was -0.49° (range -12.62° to 10.37°, SD 3.95°), and the majority of differences were within the 95% limits of agreement. CONCLUSION: The cup versions measured with SL radiography were close to the CT measurements. SL radiograph method is reliable and valid for measuring acetabular component version after THA.

Spinopelvic mobility affects accuracy of acetabular anteversion measurements on cross-table lateral radiographs.

AIMS: Cross-table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). The CTL measurements may differ by > 10° from CT scan measurements but the reasons for this discrepancy are poorly understood. Anteversion measurements from CTL radiographs and CT scans are compared to identify spinopelvic parameters predictive of inaccuracy. METHODS: THA patients (n = 47; 27 males, 20 females; mean age 62.9 years (SD 6.95)) with preoperative spinopelvic mobility, radiological analysis, and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on postoperative CTL radiographs and CT scans using 3D reconstructions of the pelvis. Two cohorts were identified based on a CTL-CT error of ≥ 10° (n = 11) or < 10° (n = 36). Spinopelvic mobility parameters were compared using independent-samples t-tests. Correlation between error and mobility parameters were assessed with Pearson's coefficient. RESULTS: Patients with CTL error > 10° (10° to 14°) had stiffer lumbar spines with less mean lumbar flexion (38.9°(SD 11.6°) vs 47.4° (SD 13.1°); p = 0.030), different sagittal balance measured by pelvic incidence-lumbar lordosis mismatch (5.9° (SD 18.8°) vs -1.7° (SD 9.8°); p = 0.042), more pelvic extension when seated (pelvic tilt -9.7° (SD 14.1°) vs -2.2° (SD 13.2°); p = 0.050), and greater change in pelvic tilt between supine and seated positions (12.6° (SD 12.1°) vs 4.7° (SD 12.5°); p = 0.036). The CTL measurement error showed a positive correlation with increased CTL anteversion (r = 0.5; p = 0.001), standing lordosis (r = 0.23; p = 0.050), seated lordosis (r = 0.4; p = 0.009), and pelvic tilt change between supine and step-up positions (r = 0.34; p = 0.010). CONCLUSION: Differences in spinopelvic mobility may explain the variability of acetabular anteversion measurements made on CTL radiographs. Patients with stiff spines and increased compensatory pelvic movement have less accurate measurements on CTL radiographs. Flexion of the contralateral hip is required to obtain clear CTL radiographs. In patients with lumbar stiffness, this movement may extend the pelvis and increase anteversion of the acetabulum on CTL views. Reliable analysis of acetabular component anteversion in this patient population may require advanced imaging with a CT scan. Cite this article: Bone Joint J 2021;103-B(7 Supple B):59-65.

A sagittal reference line using the preoperative radiograph in total knee arthroplasty.

BACKGROUND: We evaluated the accuracy of a sagittal alignment of tibial component in total knee arthroplasty (TKA) with the sagittal reference line using the preoperative radiograph. METHODS: We evaluated 151 patients who underwent primary TKA with posterior cruciate substituting type implant. For 75 patients, the sagittal reference line using preoperative radiograph (group A) was used, while for 76 patients the sagittal reference using intraoperative fibular shaft line (group B) was used. The parallel line (line S) to the anatomical axis of the tibia in the lateral plain radiograph was used as the sagittal reference. The distance from line S to proximal tibia cutting area and to skin surface 20 cm distal to the cutting area was measured in preoperative radiographs. Next, the distance to the extramedullary guide rod was applied intraoperatively, reflecting the results. The intraoperative fibular shaft line was determined using the connecting line between the tip of fibular head and the lateral malleolus. The postoperative tibial component slope angle and the difference to the target slope angle were compared. RESULTS: The difference to the target angle was 1.8 ± 1.3° in group A, whereas the difference was 2.5 ± 1.4° in group B (p = 0.04). The patients with difference within 3° to the target angle were 78.7% in group A and 61.8% in group B (p = 0.024). CONCLUSION: The sagittal reference line using the preoperative lateral radiograph was helpful as a reference guide for the tibial slope in TKA.

Projection of the Most Anterior Line of the Spinal Canal on Lateral Radiograph: An Anatomic Study for Percutaneous Kyphoplasty and Percutaneous Vertebroplasty.

ABSTRACTPurpose: To measure the projection of the most anterior line of the spinal canal on lateral radiographs of the vertebra (C3-L5) and evaluate the efficacy of the safety line (SL) in preventing intraspinal cement leakage in percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP). Materials and Methods: Fifteen adult dry-bone spine specimens were analyzed. The projection of the SL was viewed on lateral radiographs. The distance between the SL and the posterior vertebral body line (PVBL) was measured. Two groups of patients were treated by PKP, and cement injection was stopped either before the PBVL (group 1) or before the SL (group 2) under lateral fluoroscopy. The rate of cement leakage was compared between the two groups. Results: The largest distance between the SL and PVBL was at L1 (5.22 ± 0.62 mm). From L1 to L5, the distance decreased progressively to 1.05 ± 0.64 mm. Similar variation was also observed from L1 to T1 (0.19 ± 0.18 mm). The postoperative computed tomography scan was more sensitive and accurate in detecting intraspinal leakage than radiography in group 1 (p = 0.000); however, there was no significant difference in sensitivity or accuracy between methods in group 2 (p = 0.063). The rate of intraspinal cement leakage was significantly higher in group 1 than group 2 (p = 0.000). Conclusions: The operator should frequently check to ensure that cement injection has stopped upon reaching the SL. Surgeons may benefit from this quantitative anatomical study of PKP and PVP.

Evaluating Cervical Sagittal Alignment in Cervical Myelopathy: Are Sitting Cervical Radiographs and Standing Whole-Spine Radiographs Equally Useful?

STUDY DESIGN: Retrospective review of medical charts and radiographic data. OBJECTIVES: We aimed to clarify the differences in cervical alignment findings between sitting cervical lateral radiographs and standing whole-spine lateral radiographs with clavicle positioning in cervical spondylotic myelopathy (CSM) patients. METHODS: We retrospectively evaluated the radiographs of 50 consecutive patients who underwent cervical surgery for CSM in our hospital. Cervical sagittal alignment was evaluated based on the C0-2 angles and C2-7 Gore and Cobb angles. Head position was evaluated in terms of the center of gravity of the head to C7 (CGH-C7) angle and the McGregor angle (ie, the angle between the McGregor line and a horizontal line). The T1-slope was also evaluated. RESULTS: The mean values of the CGH-C7 angle and T1-slope were significantly lower, while the mean value of the McGregor angle was significantly higher on whole-spine lateral radiographs with clavicle positioning than on sitting cervical lateral radiographs. The mean values of the C0-2 and C2-7 angles did not differ significantly between the 2 radiographic positioning approaches. CONCLUSIONS: Using whole-spine lateral radiographs with clavicle positioning may result in a significantly lower T1-slope and a posterior tilt of the head. In the absence of a compensatory change in cervical alignment, clavicle positioning may force patients to adopt an upward gazing position of the head. These compensatory mechanisms should be considered while evaluating cervical alignment on whole-spine lateral radiographs with clavicle positioning. Surgical planning should take into account the effect of posture on the radiographic appearance of cervical alignment.

Combination of whole-spine lateral radiograph and lateral scanogram in the assessment of global sagittal balance.

BACKGROUND CONTEXT: Global balance of human standing is analyzed as the geometric sum of the individual alignments extending from the spinal column to the pelvis, and to the lower limbs. The innovative EOS system has opened new perspectives for the global analysis of whole-body alignment, but its use is very limited because of its high cost. An alternative may be to combine the whole-spine lateral radiograph and the lateral scanogram in the global sagittal analysis of whole-body alignment. PURPOSE: We examined to determine the validity and reliability of a lateral scanogram in the measurement of sacropelvic parameters. STUDY DESIGN/SETTING: A retrospective radiological study was carried out. PATIENT SAMPLE: We randomly selected 100 sets of digital radiographs, both whole-spine radiographs and lower-limb scanograms, from our database. OUTCOME MEASURES: Sacropelvic parameters, including pelvic incidence, sacral slope, and pelvic tilt, were measured on both whole-spine radiographs and lower-limb scanograms by three independent examiners on three separate occasions. METHODS: Agreement regarding the measurements on both image types was calculated to assess the validity of the lateral scanogram for use in whole-body alignment determinations. Intraobserver and interobserver reliabilities among the types of measurements were calculated. RESULTS: The sacropelvic area on the lateral scanogram was not visible in 19 patients (19%). In the remaining 81 patients, the sacropelvic parameters on the lateral scanogram were similar to those on the whole-spine lateral radiograph (Pearson correlation coefficient, 0.764-0.805). Intraobserver and interobserver reproducibilities for both modalities were good to excellent (intraclass correlation coefficient, 0.657-0.984). CONCLUSIONS: Sacropelvic parameter measurements on lateral scanogram were reliable and were similar to those measured on whole-spine lateral radiograph. Thus, global alignment can be evaluated using the lateral scanogram in combination with the whole-spine lateral radiograph.

The influence of the hips position on measurements of posterior tilt in a valgus-impacted femoral neck fracture.

INTRODUCTION: Lateral radiographs are important for the evaluation of Garden I and II femoral neck fractures. These fractures appear undisplaced in the anteroposterior view, but posterior tilt of the femoral head may still be present in the lateral view. The influence of posterior tilt is, however, debated, which could be caused by the use of non-standardized cross-table radiographs in the conflicting reports. The aim of this bone-model study was therefore to evaluate the influence of the hips position on measurements of posterior tilt. MATERIALS AND METHODS: We generated models of a Garden I-II femoral neck fracture and the non-injured contralateral femur from CT reconstructions with a 3D-printer. Lateral radiographs of the models were obtained in positions ranging from 90° internal rotation (IR) to 90° external rotation (ER) and 0-80° flexion. Two investigators independently measured posterior tilt on 27 lateral radiographs obtained from each model. RESULTS: The inter-tester ICC was 0.91 (0.84-0.94), standard error of measurement (SEM) 2.6, and minimal detectable change (MDC) 7.2. The median (range) posterior tilt for the fracture model was 21.9° (5.0, 33.8) and 23.6° (2.2, 28.6) for observer 1 and observer 2, respectively. The corresponding posterior tilt within the range of 10° IR to 40° ER and 0 to 30° flexion of the fracture model, was 27.3° (24.0, 33.8) and 26.3° (24.8, 28.6). DISCUSSION: The range of posterior tilt measurements for positions of the proximal femur restricted from 10° IR to 40° ER and 0 to 30° flexion, was above the MDC for observer 1, and below the MDC for observer 2. These findings indicate that rotation and flexion affect measurements of posterior tilt, but the influence may be negligible for positions of the injured extremity that are clinically relevant during cross-table lateral radiographs. A larger study that accounts for variations in anatomy and fracture displacement is required to confirm these findings.

Radiographic Comparison between Cervical Spine Lateral and Whole-Spine Lateral Standing Radiographs.

Study Design Retrospective radiologic study. Objective The sagittal alignment of the cervical spine can be evaluated using either a lateral cervical radiograph or a whole-spine lateral view on which the cervical spine is included. To our knowledge, however, no report has compared the two. The purpose of this work is to identify the difference in radiographic parameters between the cervical spine lateral view and the whole-spine lateral view. Methods We retrospectively analyzed 59 adult patients suffering from neck pain with cervical spine lateral radiographs and whole-spine lateral radiographs from November 2007 to December 2011. The radiographs were measured using standard techniques to obtain the following parameters from the two different radiographs: occipital-C2 angle, C2-C7 angle, C7-sternal angle, sternal slope, T1 slope, C2 central offset distance, the distance between C2 and C7 plumb lines, C4 anteroposterior (AP) diameter, the ratio of C2 central off distance to C4 AP diameter, the ratio of plumb lines' distance to C4 AP diameter. Results We found that the occipital-C2 angle, sternal slope, and C4 AP diameter were similar, but the C2-C7 angle, C7-sternal angle, T1 slope, C2 central offset distance, distance between C2 and C7 plumb lines, ratio of C2 central off distance to C4 AP diameter, and ratio of plumb lines' distance to C4 AP diameter were different. However, the error of measurement was greater than the small angular and linear differences between the two views. Conclusions Most numerical values of the measured radiographic parameters appear to be different between the two views. However, the two views are comparable because the numerical differences were smaller than the errors of measurement.

Focal intratendinous radiolucency: A new radiographic method for diagnosing patellar tendon ruptures.

BACKGROUND: Diagnosis of patellar tendon rupture is usually based on clinical history and examination. In equivocal cases, imaging may be required. Lateral radiograph is a simple and cost-effective method for prompt diagnosis. However, no specific radiological sign has been described. Rather than utilising patella alta as an indirect measure of patellar tendon rupture, we hypothesise that a focal intratendinous radiolucency is another reliable and accurate radiological sign for diagnosis. Sensitivity and specificity analysis was undertaken to evaluate the diagnostic value of this radiographic sign. METHODS: Lateral radiographs of mid-substance patellar tendon ruptures from 19 patients were analysed. These were then randomised with another 19 normal knee radiographs from age-matched patients to create a pool of 38 radiographs for interpretation. Six independent interpreters who were blinded to the diagnosis were requested to indicate whether rupture was present or absent based on the visualisation of a focal intratendinous radiolucency in the patellar tendon. The Insall-Salvati (IS), Caton-Deschamps (CD) and Blackburne-Peel (BP) ratios were measured in the same radiographs. Sensitivity and specificity for each of the radiographic measurements were calculated. Inter- and intraobserver correlations were reported in kappa statistics. RESULTS: The average sensitivity and specificity for focal radiolucency in the patellar tendon substance were 82.5% and 95.2%, respectively. Sensitivity and specificity for the IS ratio were 84.2% and 78.9%, for CD was 68.4% and 84.2% and for BP was 68.4% and 89.4% respectively. CONCLUSION: The presence of a focal intratendinous radiolucency in the patellar tendon is both accurate and reliable in diagnosing patellar tendon ruptures.