Lateral Radiographic Measurements Research Articles

Correlation Between Traditional Anteroposterior Radiographic Measurements With Lateral Radiographic Measurements Following Triplanar Correction of Hallux Valgus and With Patient-Reported Outcomes From a Prospective Multicenter Trial

Hallux valgus (HV) is a common condition in which the first ray is deformed, leading to pain and altered joint mechanics. A variety of radiographic measurements are used to evaluate HV. Little is known about measurements used in the assessment of HV on lateral radiographs compared to anteroposterior (AP) radiographs. The primary aim of this study was to correlate lateral measurements with AP measurements pre and postoperatively. The secondary aim was to correlate lateral measurements with patient-reported outcome measures (PROMs) pre and postoperatively.One hundred eighty-three patients were initially enrolled in the study. Two fellowship-trained musculoskeletal radiologists independently performed all measurements. On AP radiographs, hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured. On lateral radiographs, sagittal IMA, Meary's angle, and sagittal first ray length were measured. Measurements were recorded at baseline and 6, 12, and 24 months postoperatively. Intraclass correlation coefficients (ICCs) were used for inter-reader analysis. ICCs were moderate to very strong among readers. There were significant but weak correlations between lateral measurements and AP measurements. For at least 1 timepoint, IMA correlated with sagittal IMA, sagittal first ray length, and Meary's angle. HVA only correlated with sagittal first ray length. These correlations were all weak in magnitude. There were a few significant but weak correlations between the measurements in the study and PROMs. This study showed that sagittal IMA, sagittal first ray length, and Meary's angle are not predictive of AP measurements or patient outcomes and are not useful in preoperative assessment of HV.

O36: Classification of joint gait patterns in children with hereditary spastic paraplegia

Retrospective.To develop and validate a prediction formula to estimate three-dimensional (3D) T5–T12 kyphosis in adolescent idiopathic scoliosis (AIS) from standard two-dimensional (2D) radiographic measurements.2D measurements of thoracic kyphosis in AIS patients overestimate 3D kyphosis; however, there is a lack of widespread availability of 3D imaging technology.Retrospective review was performed for AIS patients with right thoracic curves evaluated with EOS Imaging from January 2010 to June 2014. Standard 2D posteroanterior and lateral radiographic measurements, pelvic incidence, Nash-Moe grade, Perdriolle rotation, and “3D T5–T12” sagittal measures (reconstructed with sterEOS, analyzed with custom MatLab code) were input into a multivariate logistic analysis to create a prediction model for 3D T5–T12 sagittal alignment. An initial cohort of 66 patients (curves 14°–85°) was used to create a predictive model, and a separate cohort of 129 patients (curves 16°–84°) was used to validate the formula.2D thoracic coronal Cobb and 2D T5–T12 kyphosis were the only significant predictors in the model. The prediction formula for estimating 3D T5–T12 sagittal measurement from standard 2D measurements, in degrees, was 18.1 + (0.81*2D T5–T12 sagittal Cobb) − (0.54*2D coronal Cobb), r2 = 0.84. The average model error between predicted and measured 3D T5–T12 kyphosis was ±7°. The predicted 3D T5–T12 kyphosis (8.6° ± 12.1°) and measured 3D T5–T12 kyphosis (8.5° ± 13.0°) were not significantly different (p = .8). 3D kyphosis was less than standard measures of 2D kyphosis (8.5° ± 13.0° vs. 20.2° ± 12.6°, p < .001).This simple validated formula to predict 3D T5–T12 sagittal alignment using routine 2D thoracic Cobb and T5–T12 kyphosis for thoracic AIS patients has great potential value in assessing historical data collected prior to the development of 3D imaging methods as well as understanding/planning surgical hypokyphosis correction in patients without access to 3D imaging.

Predicting 3D Thoracic Kyphosis Using Traditional 2D Radiographic Measurements in Adolescent Idiopathic Scoliosis

Study DesignRetrospective. ObjectiveTo develop and validate a prediction formula to estimate three-dimensional (3D) T5–T12 kyphosis in adolescent idiopathic scoliosis (AIS) from standard two-dimensional (2D) radiographic measurements. Summary of Background Data2D measurements of thoracic kyphosis in AIS patients overestimate 3D kyphosis; however, there is a lack of widespread availability of 3D imaging technology. MethodsRetrospective review was performed for AIS patients with right thoracic curves evaluated with EOS Imaging from January 2010 to June 2014. Standard 2D posteroanterior and lateral radiographic measurements, pelvic incidence, Nash-Moe grade, Perdriolle rotation, and “3D T5–T12” sagittal measures (reconstructed with sterEOS, analyzed with custom MatLab code) were input into a multivariate logistic analysis to create a prediction model for 3D T5–T12 sagittal alignment. An initial cohort of 66 patients (curves 14°–85°) was used to create a predictive model, and a separate cohort of 129 patients (curves 16°–84°) was used to validate the formula. Results2D thoracic coronal Cobb and 2D T5–T12 kyphosis were the only significant predictors in the model. The prediction formula for estimating 3D T5–T12 sagittal measurement from standard 2D measurements, in degrees, was 18.1 + (0.81*2D T5–T12 sagittal Cobb) − (0.54*2D coronal Cobb), r2 = 0.84. The average model error between predicted and measured 3D T5–T12 kyphosis was ±7°. The predicted 3D T5–T12 kyphosis (8.6° ± 12.1°) and measured 3D T5–T12 kyphosis (8.5° ± 13.0°) were not significantly different (p = .8). 3D kyphosis was less than standard measures of 2D kyphosis (8.5° ± 13.0° vs. 20.2° ± 12.6°, p < .001). ConclusionThis simple validated formula to predict 3D T5–T12 sagittal alignment using routine 2D thoracic Cobb and T5–T12 kyphosis for thoracic AIS patients has great potential value in assessing historical data collected prior to the development of 3D imaging methods as well as understanding/planning surgical hypokyphosis correction in patients without access to 3D imaging.

Upright magnetic resonance imaging measurement of prevertebral soft tissue in the cervical spine of normal volunteers

Background context Anteroposterior width of prevertebral soft tissues (PVSTs) in the cervical spine has long been considered a valuable radiographic measurement for evaluation of occult cervical spine pathology. These measurements, generally obtained from lateral radiographs of the cervical spine, have been used clinically as references for the evaluation of patients with traumatic, neoplastic, or other cervical spine disorders. Magnetic resonance imaging (MRI) offers a subtle delineation of the soft-tissue structures anterior to the vertebral column, with the potential for more accurate and sensitive determination of PVST width. Upright magnetic resonance images permit comparison with and validation of previously reported upright lateral radiographic measurements of PVST width. To our knowledge, evaluation of cervical spine PVST width using upright MRI has not been previously published in the English literature. Purpose The purposes of this study were to validate lateral radiographic measurements of PVST width using upright weight-bearing MRI in healthy subjects and quantify effects of spinal level and gender. Study design Clinical study in asymptomatic volunteers. Methods Eleven male and eight female volunteers consented and were enrolled in the study. All volunteers were asymptomatic and had no history of cervical spine injury or degenerative disease. Prevertebral soft-tissue width was measured at each cervical level from C2 to C7 using upright weight-bearing MRI. Statistically significant differences in PVST width based on spinal level and gender were determined using two-factor analysis of variance. Results Width magnitudes were significantly dependent on gender (p<.0001) and spinal level (p<.0001). All C3 and C6 measurements were below the traditionally accepted values of 7 and 20 mm, respectively, that would be considered “abnormal.” Prevertebral soft-tissue width was greater in men at upper and lower extents of the cervical spine. Prevertebral soft-tissue widths reported in the present study were similar in magnitude and level-by-level trends to measurements of asymptomatic volunteers obtained using lateral radiography. Conclusion The present study validated the use of lateral radiography to measure PVST width, presented level-by-level and gender-specific normative data, and provided a weighted statistical analysis of differences between normal volunteers and injured patients.

Assessment of adenoid size: A comparison of lateral radiographic measurements, radiologist assessment, and nasal endoscopy

Objectives Correlate adenoid size as determined by lateral neck radiographs and intra-operative mirror exam. Determine if a radiologist's assessment of the lateral neck X-ray correlates with adenoid size. Assess the correlation of endoscopic findings to the degree of adenoid hypertrophy seen on intra-operative mirror exam. To perform a cost analysis of radiographic and endoscopic evaluations of the adenoids. Study design Retrospective study. Methods Patients who underwent adenoidectomy were reviewed. The adenoid size as determined by the adenoid-to-nasopharyngeal (A/N) ratio, radiology report, and flexible nasal endoscopy were compared to the adenoid size as determined by intra-operative mirror nasopharyngeal exam. Compensation rates for each modality were compared. Results Sixty-one children had pre-operative airway radiography. Ninety-nine patients underwent flexible nasopharyngoscopy. When the A/N ratio was compared to the intra-operative mirror exam, the Pearson Correlation coefficient was 0.64 ( p < 0.0001). The radiology reading was compared to intra-operative mirror exam and the Spearman Correlation coefficient was 0.29 ( p = 0.0258). When endoscopic nasopharyngoscopy was compared to intra-operative mirror exam, the Pearson Correlation coefficient was 0.62 ( p < 0.0001). The cost of nasal endoscopy was $654. Lateral airway radiography plus radiology interpretation cost $605. Conclusion Children who undergo lateral radiographs to assess adenoid size are younger than those who undergo awake flexible endoscopic nasopharyngoscopy. Both the A/N ratio and endoscopic nasopharyngoscopy correlate well with the findings of the intra-operative mirror exam. The radiologist interpretations that do not utilize the A/N ratio measurement do not correlate well with intra-operative mirror exam findings. Both modalities are comparable in cost.

A Guide Frame for the Taylor Spatial Frame

The Taylor Spatial Frame (TSF) is a versatile multiplanar external fixator that combines ease of application with computer accuracy to effectively reduce fractures and correct all aspects of deformity in reconstructive orthopaedic surgery. However, postapplication adjustments depend on adequate anteroposterior and lateral radiographic measurements to yield the most accurate output from the program. These radiographs need to be taken in an orthogonal plane to the reference ring. We describe a noninvasive technique using a specifically designed radiolucent frame that can be attached to the TSF to guide the surgeon and radiologist in obtaining lateral and anteroposterior radiographs, with the reference ring perfectly orthogonal in single exposures for each radiographic view. By using this guiding frame, reproducible and consistent x-rays oriented orthogonally to the reference ring at different points in the correction may be achieved, thus eliminating the need for repeat radiographs and radiation exposure for patients, radiologists, and surgeons. In this manner, the mounting parameters and the orientation of the bony deformity will be consistent. This should lead to enhanced accuracy of the TSF correction.

Comparison of distal and proximal centralising devices in hip arthroplasty

Centralising devices were introduced to ensure that the prosthesis is implanted in a neutral position and that a cement mantle of optimal thickness is achieved proximally and distally. A distal centralising device (DCD) is compared with a proximal midshaft centralising device (PCD) to test which one provides a more neutral prosthetic alignment. Thirty consecutive patients undergoing hemiarthroplasties for femoral neck fractures were studied prospectively. Patients were blindly randomised to receive either a femoral component with proximal midshaft centraliser or distal centraliser. Both components were implanted following the manufacturer's protocol. Postoperative true anteroposterior and lateral radiographs were made to assess the stem position. There was no statistically significant difference between the two groups in zones 1, 2, 3, 4, 5, 6 and 7 in both anteroposterior and lateral radiographic measurements. DCP and PCD both have similar centralisation and cement mantle. Future studies should be done to evaluate their long-term effect.

The Role of the Dynamic Pedobarograph in Assessing Treatment of Cavovarus Feet in Children With Charcot-Marie-Tooth Disease

We used the dynamic pedobarographs to study pressure distribution patterns in the foot after surgical correction of cavovarus feet. We also assessed the influence of ankle power generation on pressure distribution in these feet. Nine children (14 feet) diagnosed with Charcot-Marie-Tooth disease who had undergone operative treatment with a combination of osteotomies and muscle transfers were the subjects of this study. Preoperative and postoperative pedobarographic measurements recorded included pressure over the medial forefoot, lateral forefoot, medial midfoot (MMF), lateral midfoot (LMF), and heel segments. In 6 patients (9 feet) who had a complete gait analysis, the power generation of the ankle was also obtained both preoperatively and postoperatively. Lateral radiographic measurements included the (1) talus-first metatarsal angle, (2) calcaneus-first metatarsal angle, and (3) calcaneal pitch. The radiographs showed significant improvements in all 3 angles. Increased LMF and decreased forefoot pressures were seen on preoperative pedobarographic measures. Postoperatively, improvement in pressure at the LMF was seen. When postoperative measurements were compared with the normal values, only the LMF was similar; the other 4 segments showed decreased forefoot and MMF pressures and increased heel pressures (P = 0.000 for the lateral forefoot and MMF; 0.040 for the heel and medial forefoot). The heel pressures displayed an inverse relationship to ankle power generation. The amount of correction achieved radiographically did not correlate with pedobarographic measurements. The increased heel pressure that was noted was not addressed by treatment. Normalization of pressure patterns should be the goal in treating children with symptomatic cavovarus feet. Although the foot deformity is corrected completely in neuromuscular disorders, pressure distribution was not normalized, and therefore, symptoms might persist. Both patients and parents should be informed about this possible problem before surgical intervention.

Correction of Tibial Deformity with Use of the Ilizarov-Taylor Spatial Frame

The Ilizarov-Taylor Spatial Frame (TSF; Smith and Nephew, Memphis, Tennessee) is a powerful tool for correcting tibial deformity1-6. A specialized feature of the TSF is its virtual hinge, which allows for the simultaneous gradual correction of multiplanar deformities and limb-lengthening through one osteotomy site. The power of the spatial frame lies in its precise control over the final limb length and alignment and in its ability to correct a residual deformity. The stability of this multiplanar circular fixator permits early weight-bearing and provides an ideal environment for both new-bone formation and soft-tissue healing. The classic principles of the Ilizarov method are followed to ensure proper frame application. The TSF web-based software is user-friendly and has greatly simplified the planning of the correction of an oblique plane deformity by utilizing standard anterior-posterior and lateral radiographic measurements. Computer-generated schedules and easy-to-read struts have greatly simplified patient involvement, which is crucial to the success of this technique. ### Preoperative Planning Patients are evaluated clinically by a history and physical examination including observation of gait. Special attention is directed toward the assessment of leg length, mechanical axis deviation, and rotational alignment (Fig. 1). An erect bipedal 51-in (130-cm) radiograph in the frontal plane is made. If there is a leg-length discrepancy, then blocks are placed under the affected foot to level the pelvis, and the block height is recorded. Accurate limb lengths are measured in this way. Sagittal deformity about the knee is evaluated with a 36-in (91-cm) lateral radiograph made with the knee in full extension. Routine anteroposterior and lateral radiographs of the tibia are made as well. Ankle deformity should be evaluated with the x-ray beam centered on the ankle. Mechanical axis deviation is determined with use of the malalignment test7,8 (Fig. 2). The lateral distal femoral angle, …