Assessment Of Lower Limb Alignment Research Articles

Assessment of lower limb alignment: supine weight-bearing CT scanograms compared with a standing full-length radiograph.

We identified limb misalignment by applying personalized axial force while the limb was in a supine position to mimic a standing posture. This study aimed to confirm the accuracy of evaluating lower limb alignment using supine weight-bearing CT scanograms. We prospectively compared measurements of the weight-bearing line ratio (WBL), hip-knee-ankle (HKA) angle, and joint convergence angle (JLCA) in 46 sets of supine weight-bearing CT scanograms with those obtained from full-length standing anteroposterior lower extremity radiographs. We achieved the weight-bearing CT scanograms by applying six different levels of axial force: zero, 1/5 of body weight, 2/5 of body weight, 3/5 of body weight, 4/5 of body weight, and full body weight. We assessed the impact of age, body mass index, HKA, and JLCA on the observed mechanical axis deviation differences between the two methods. The average absolute difference between standing radiographs and supine CT scanograms was 4.32% for the WBL ratio (p < 0.05), 1.25° for HKA (p < 0.05), and 0.46 for JLCA (p < 0.05). The mean absolute difference was minimal when applying full body weight axial pressure during CT scanograms (p > 0.05). Age, body mass index, HKA, and JLCA had no effect on the deviation in the mechanical axis measurements obtained through supine weight-bearing CT scanograms with full body weight. No significant differences were found in assessing lower limb alignment between standing radiographs and supine weight-bearing CT scanograms with full body weight. Weight-bearing CT scanograms prove to be a valuable method for assessing lower limb alignment while in a supine position.

Segmentation-guided coordinate regression for robust landmark detection on X-rays: application to automated assessment of lower limb alignment

Segmentation-guided coordinate regression for robust landmark detection on X-rays: application to automated assessment of lower limb alignment

A deep learning approach for fully automated measurements of lower extremity alignment in radiographic images

During clinical evaluation of patients and planning orthopedic treatments, the periodic assessment of lower limb alignment is critical. Currently, physicians use physical tools and radiographs to directly observe limb alignment. However, this process is manual, time consuming, and prone to human error. To this end, a deep-learning (DL)-based system was developed to automatically, rapidly, and accurately detect lower limb alignment by using anteroposterior standing X-ray medical imaging data of lower limbs. For this study, leg radiographs of non-overlapping 770 patients were collected from January 2016 to August 2020. To precisely detect necessary landmarks, a DL model was implemented stepwise. A radiologist compared the final calculated measurements with the observations in terms of the concordance correlation coefficient (CCC), Pearson correlation coefficient (PCC), and intraclass correlation coefficient (ICC). Based on the results and 250 frontal lower limb radiographs obtained from 250 patients, the system measurements for 16 indicators revealed superior reliability (CCC, PCC, and ICC ≤ 0.9; mean absolute error, mean square error, and root mean square error ≥ 0.9) for clinical observations. Furthermore, the average measurement speed was approximately 12 s. In conclusion, the analysis of anteroposterior standing X-ray medical imaging data by the DL-based lower limb alignment diagnostic support system produces measurement results similar to those obtained by radiologists.

Intra- and interobserver reliability analysis of pediatric lower limb parameters on digital long leg radiographs

BackgroundMalalignments of the lower extremity are common reasons for orthopedic consultation because it may lead to osteoarthritis in adulthood. An accurate and reliable radiological assessment of lower limb alignment in children and adolescents is essential for clinical decision-making on treatment of limb deformities and for regular control after a surgical intervention.ObjectiveFirst, does the analysis of full-length standing anteroposterior radiographs show a good intra- and interobserver reliability? Second, which parameter is most susceptible to observer-dependent errors? Third, what is the Standard Error of Measurement (SEM95%) of the absolute femoral and tibial length?MethodsTwo observers evaluated digital radiographs of 144 legs from 36 children and adolescents with pathological valgus alignment before a temporary hemiepiphysiodesis and before implant removal. Parameters included Mechanical Femorotibial Angle (MFA), Mechanical Axis Deviation (MAD), mechanical Lateral Distal Femoral Angle (mLDFA), mechanical Medial Proximal Tibial Angle (mMPTA), mechanical Lateral Proximal Femoral Angle (mLPFA), mechanical Lateral Distal Tibial Angle (mLDTA), Joint Line Convergence Angle (JLCA), femur length, tibial length. Intra- and interobserver reliability (ICC2,1), SEM95% and proportional errors were calculated.ResultsThe intra- and interobserver reliability for almost all measurements was found to be good to excellent (Intra-ICC2,1: 0.849–0.999; Inter-ICC2,1: 0.864–0.996). The SEM95% of both observers was found to be ± 1.39° (MFA), ± 3.31 mm (MAD), ± 1.06° (mLDFA) and ± 1.29° (mMPTA). The proportional error of MAD and MFA is comparable (47.29% vs. 46.33%). The relevant knee joint surface angles show a lower proportional error for mLDFA (42.40%) than for mMPTA (51.60%). JLCA has a proportional error of 138%. Furthermore, the SEM95% for the absolute values of the femoral and tibial length was 4.53 mm for the femur and 3.12 mm for the tibia.ConclusionsIn conclusion, a precise malalignment measurement and the knowledge about SEM95% of the respective parameters are crucial for correct surgical or nonsurgical treatment. The susceptibility to error must be considered when interpreting malalignment analysis and must be considered when planning a surgical intervention. The results of the present study elucidate that MAD and MFA are equally susceptible to observer-dependent errors. This study shows good to excellent intra- and interobserver ICCs for all leg alignment parameters and joint surface angles, except for JLCA.Trial registration: This study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053.Level of evidenceI, Diagnostic Study.

Radiographic assessment of lower limb alignment in South African children

Radiographic assessment of lower limb alignment in South African children

Automated Artificial Intelligence-Based Assessment of Lower Limb Alignment Validated on Weight-Bearing Pre- and Postoperative Full-Leg Radiographs.

The assessment of the knee alignment using standing weight-bearing full-leg radiographs (FLR) is a standardized method. Determining the load-bearing axis of the leg requires time-consuming manual measurements. The aim of this study is to develop and validate a novel algorithm based on artificial intelligence (AI) for the automated assessment of lower limb alignment. In the first stage, a customized mask-RCNN model was trained to automatically detect and segment anatomical structures and implants in FLR. In the second stage, four region-specific neural network models (adaptations of UNet) were trained to automatically place anatomical landmarks. In the final stage, this information was used to automatically determine five key lower limb alignment angles. For the validation dataset, weight-bearing, antero-posterior FLR were captured preoperatively and 3 months postoperatively. Preoperative images were measured by the operating orthopedic surgeon and an independent physician. Postoperative images were measured by the second rater only. The final validation dataset consisted of 95 preoperative and 105 postoperative FLR. The detection rate for the different angles ranged between 92.4% and 98.9%. Human vs. human inter-(ICCs: 0.85-0.99) and intra-rater (ICCs: 0.95-1.0) reliability analysis achieved significant agreement. The ICC-values of human vs. AI inter-rater reliability analysis ranged between 0.8 and 1.0 preoperatively and between 0.83 and 0.99 postoperatively (all p &lt; 0.001). An independent and external validation of the proposed algorithm on pre- and postoperative FLR, with excellent reliability for human measurements, could be demonstrated. Hence, the algorithm might allow for the objective and time saving analysis of large datasets and support physicians in daily routine.

Intraoperative alignment correlates well with long standing radiographs - The X-ray grid method in complex knee surgery

ObjectiveWhile long standing radiographs (LSR) represent the gold standard for preoperative alignment assessment and planning of lower limb deformity corrections, there is no consensus about the intraoperative alignment assesments (IAC) due to various limitations of the common methods. The present study introduces a radiolucent X-ray grid with integrated radiopaque lines explicitly designed for fluoroscopic IAC and evaluates its reliability in comparsion to the LSR. MethodsPatients with posttaumatic and congenital lower limb deformity surgery and preoperative LSR as well as fluoroscopic IAC utilizing the X-ray grid were retrospectively included to the study. The mechanical axis deviation (MAD) in percentage of the maximum tibial width from the medial to the lateral in comparison between the image pairs was set as primary outcome parameter. Multiple rater and measurements determined intra- and interobserver reliabilit of both imaging methods. In addition, the effects of age, gender, body mass index (BMI), etiology, joint line convergence angle (JLCA), and extent varus or valgus deformity were analysed. ResultsA total of 84 patients were finally included. The mean absolute difference of MAD between the two techniques was 7.2 ± 0.8%. MAD between the LSR and IAC correlated at a high level (R = 0.96, p <0.001). The agreement decreased with increasing extent of deformity (p <0.01) and with higher deviation of JLCA between LSR and IAC (p <0.01). Intra- and interobserver concordance correlation coefficient (CCC) for MAD measurements were 0.99 for both imaging techniques. ConclusionFluoroscopy combined with the X-ray grid method is a valid tool for intraoperative assessment of lower limb alignment in deformity correction surgery, and the correlation between LSR and IAC is better than in other similar techniques described in the literature. However, in case of severe coronal alignment deformity and highly divergent JLCA, the agreement between both imaging techniques decreases significantly.

Radiological assessment of lower limb alignment.

The full-length standing radiograph in an anteroposterior projection is the primary tool for defining and measuring limb alignment with definition of the physiological axes and mechanical and anatomic angles of the lower limb.We define the deformities of the lower limb and the importance of correct surgical planning and execution.For patients with torsional malalignment of the lower limb, computerized tomography scan evaluation is the gold standard for preoperative assessment.Cite this article: EFORT Open Rev 2021;6:487-494. DOI: 10.1302/2058-5241.6.210015

Three-dimensional assessment of lower limb alignment: Reference values and sex-related differences

BackgroundThree-dimensional (3D) preoperative planning and assisted surgery is increasingly popular in deformity surgery and arthroplasty. Reference ranges for 3D lower limb alignment are needed as a prerequisite for standardized analysis of alignment and preoperative planning in 3D, but are not yet established. MethodsOn 60 3D bone models of the lower limbs based on computed tomography data, fifteen parameters per leg were assessed by standardized validated 3D analysis. Distribution parameters and differences between sexes were evaluated. Reference values were generated by adding/subtracting one standard deviation from the mean. ResultsWomen had a significantly lower mean mechanical lateral distal femoral angle compared with men (86.4 ± 2.1° vs. 87.8 ± 2.0°; P < .05) and significantly lower mean joint line convergence angle (−2.5 ± 1.4° vs. -1.3 ± 1.2; P < .01), but higher mean hip knee ankle angle (178.9 ± 1.9° vs. 177.8 ± 2.3°; P < .05) and mean femoral torsion (18.2 ± 9.5° vs. 13.2 ± 6.4°; P < .05), resulting in a tendency towards valgus alignment and vice versa for men. Differences in mean medial proximal tibial angle were not significant. The mean mechanical axis deviation from the tibial knee joint center was 6.9 ± 7.3 mm medial and 1.4 ± 16.1 mm ventral without significant differences between sexes. ConclusionsWe describe total and sex-related reference ranges for all alignment relevant axes and joint angles of the lower limb. There are sex-related differences in certain alignment parameters, which should be considered in analysis and surgical planning.

Three-dimensional assessment of lower limb alignment: Accuracy and reliability

IntroductionThree-dimensional (3D) surgical planning and patient-specific implants are becoming increasingly popular in orthopedics and trauma surgery. In contrast to the established and standardized alignment assessment on two-dimensional (2D) long standing radiographs (LSRs) there is neither a standardized nor a validated protocol for the analysis of 3D bone models of the lower limb. This study aimed to create a prerequisite for pre-operative planning. MethodsAccording to 2D analysis and after meticulous research, 24 landmarks were defined on 3D bone models obtained from computed axial tomography (CT) scans for a 3D alignment assessment. Three observers with different experience levels performed the test three different times on three specimens. Intraobserver and interobserver variability of the landmarks and the intraclass correlation coefficient (ICC) of the resulting axes and joint angles were evaluated. ResultsOverall, the intraobserver and interobserver variability was low, with a mean deviation <5 mm for all landmarks. The ICC of all joint angles and axis deviations was >0.8, except for tibial torsion (ICC = 0.69). All knee joint angles showed excellent ICC (>0.95). ConclusionsUsing the defined landmarks, a standardized 3D alignment assessment with low intraobserver and interobserver variability and high ICC values for the knee joint angles can be performed regardless of examiner's experience. The described method serves as a reliable standardized protocol for a 3D malalignment test of the lower limb. Three-dimensional pre-operative analysis might enhance understanding of deformities and lead to a new focus in surgical planning.

3D Modeling of Lower Extremities With Biplanar Radiographs: Reliability of Measures on Subsequent Examinations.

Biplanar radiography with 3-dimensional (3D) modeling (EOS) provides a comprehensive assessment of lower limb alignment in an upright weight-bearing position with less radiation than conventional radiography. A study was performed to assess the consistency and reliability of 2 lower extremity 3D biplanar radiograph models created at least 1 year apart in a pediatric population. All patients who had 2 lower extremity radiographic evaluations with EOS performed at visits a minimum of 1 year apart were reviewed. Digital radiographs, of lower extremities in both frontal and sagittal planes, were acquired simultaneously, using the EOS system. The 3D reconstruction of the images was achieved utilizing the SterEOS software. Pelvic position, femoral and tibial anatomy, and the torsional profile were evaluated and compared using t tests. In total, 53 patients with a mean age of 11.7 years (range, 6.1 to 18.9 y) met inclusion criteria. When comparing 3D models between visits, minimal differences were noted in proximal femoral anatomy and pelvic alignment (pelvic incidence, sacral slope, sagittal tilt, neck shaft angle). Expected differences in femoral and tibial length corresponded with normal longitudinal growth between visits. Sagittal plane knee position varied widely between examinations. Femoral and/or tibial rotational osteotomies were performed in 37% of extremities between examinations. After femoral derotational osteotomy, a significant difference in femoral anteversion was appreciated when comparing preoperative and postoperative 3D models. However, this difference was less than the expected difference based on the anatomic correction achieved intraoperatively. No differences were noted in tibial torsion measures after tibial derotational osteotomy. The 3D modeling based on biplanar radiographs provides consistent and reliable measures of pelvic and hip joint anatomy of the lower extremity. Patient positioning may influence the reproducibility of knee alignment. The torsional profile assessment did not accurately reflect changes obtained by derotational osteotomy. Level III.

Planning of High Tibial Osteotomy

Introduction:High Tibial Osteotomy (HTO) is an establish technique for the treatment of varus malaligned knees. The aim of HTO is to reduce the load on the medial compartment by shifting the mechanical axis toward the lateral compartment. It is indisputable that appropriate patient selection, precise surgical planning, and correct operative techniques can provide favorable treatment outcomes of HTO.Method:Case Series. We reported four cases of HTO during clinical attachment in Gleneagles Hospital Kuala Lumpur Malaysia. Two cases are simple Open Wedge HTO, and two cases are Open Wedge HTO that performed simultaneously with posterolateral corner reconstruction. The assessment of lower limb alignment is based on an examination of clinical assessment and full standing radiographs, andplanned correction was achieved when the weight-bearing line passedthrough a target point located at 62% (Fujisawa point) ofthe tibial plateau width measured from themedial border of the tibial plateau.Result:We performed 90, 110, and 60 corrections to shift the weight bearing area to Fujisawa point. Post operative radiologic measurement shown all patients had a good alignment with 60, 50, and 60 valgus over correction, and with insignificant change of tibial slope. PLC instability was reconstruct with modified Larson’s technique by using semitendinous graft. In these cases, we used Tomifix plate (Sythes, Switzerland) as a bridging internal fixation with the principle of a locking compression plate (LCP), and ChronOS (Sythes, Switzerland) as a bone void filler.Conclusion:To achieve good results with HTO requires proper patient selection, good surgical planning, accurate surgical technique, and discipline rehabilitation. Reconstruction of the ligament abnormalities that affect the stability around the knee joint is necessary to achieve better results.

Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial.

This study aimed to investigate the accuracy of pinless navigation (BrainLAB(®) VectorVision(®) Knee 2.5 Navigation System) as an intra-operative alignment guide in total knee arthroplasty (TKA). The authors hypothesized that pinless navigation would reduce the proportion of outliers in conventional TKA, without a significant increase in the duration of surgery. Between 2011 and 2012, 100 patients scheduled for a unilateral primary TKA were randomized into two groups: pinless navigation and conventional surgery. All TKAs were performed with the surgical aim of achieving neutral coronal alignment with a 180° mechanical axis. The primary outcomes of this study were post-operative radiographic assessment of lower limb alignment using hip-knee-ankle angle (HKA) and components placement using coronal femoral-component angle (CFA) and coronal tibia-component angle (CTA). There was a smaller proportion of outliers for HKA, CFA and CTA at 10, 2 and 2 % respectively, in the pinless navigation group, compared to 32, 16 and 16 %, respectively, in the conventional group (p = 0.013, p = 0.032 and p = 0.032, respectively). The mean CFA was also more accurate at 90° in the pinless navigation group compared to 91° in the conventional group (p = 0.002). There was no difference in the duration of surgery between the two groups (n.s.). Pinless navigation improves lower limb alignment and components placement without a significant increase in the duration of surgery. The authors recommend the use of pinless navigation to verify the coronal alignments of conventional cutting blocks in TKA before the bone cuts are made. I.

Medial Minimally Invasive Percutaneous Plate Osteosynthesis in Proximal Tibial Comminuted Fractures

Purpose: This goal of this study is to evaluate the clinical and radiological outcomes of proximal tibial comminuted fractures treated with medial minimally invasive percutaneous plate osteosynthesis (MIPPO). Materials and Methods: We evaluated 43 patients who underwent medial MIPPO from February 2008 to February 2012 and were followed up for more than one year. According to the AO/OTA classification, there were 30 patients of 41-A3 and 13 patients of 41-C2. Thirty-six patients had closed fractures and seven patients had open fractures. We assessed clinical outcomes, radiologic results and postoperative complications. Results: All fractures were united at an average of 18.3±8.1 weeks except three patients with nonunion. According to Schatzker and Lambert assessment, excellent results were achieved for 22 patients and good results were achieved for 21 patients. The average tibial plateau angle was 89.1±2.7 and the average posterior tibial slope angle was 10.5±4.6. In assessment of lower limb alignment, the average femorotibial angle was 175.1±2.9 and the mean deviation of mechanical axis was 46.5%±12.7%. In terms of complications, three patients had nonunion, but complete bony union was achieved by autogenous cancellous bone grafting. Seven patients complained of skin irritation around the plate. However, there was no skin necrosis, infection, or limited range of motion in seven patients with skin irritation. Conclusion: Medial MIPPO for proximal tibial comminuted fractures provides favorable clinical outcomes and good radiological alignments.

Automatically Assessing Limb Alignment and Hip Fracture Using 3D Models

To allow an efficient assessment of lower limb alignment and hip fracture, 3D lower limb bone models are reconstructed from patient-specific computed tomography images. The 3D feature-construction system shown here automatically extracts 3D features (centers, auxiliary points, axes, and planes). No other work exists that automatically marks all the features for the lower extremities.

Computer-assisted navigation for the intraoperative assessment of lower limb alignment in high tibial osteotomy can avoid outliers compared with the conventional technique

Longterm outcomes after valgization high tibial osteotomy (HTO) to treat varus osteoarthritis seem to depend mainly on correction precision. Intraoperative assessment of leg alignment based on radiological visualization of the mechanical axis is difficult and its precision is limited. A promising approach to improving precision is to make use of navigation systems. The case-control study reported here involved the evaluation of patients whose varus osteoarthritis had been treated by open-wedge high tibial ostoetomy, and an analysis of the effect of computer-guided navigation on postoperative leg alignment. Forty patients with medial varus osteoarthritis managed by open-wedge high tibial osteotomy using a surgical navigation system were included in the present study (Group 1). They were compared with a retrospective control group (Group 2) of 40 patients with respect to postoperative leg alignment, correlation of planned and definitive correction, and postoperative deviation from the Fujisawa point. The mean values for planned and definitive correction showed no significant differences for identical demographic data. As a percentage of the width of the tibial plateau the postoperative weight-bearing radiographs showed a mechanical line that intersected with the knee base line at the desired value of 62% (Fujisawa point) in 58.8% (SD ± 6.1) in Group 1 and in 58.6% (SD ± 8.1) in Group 2. Despite similar mean values a significantly higher number of corrections were outside the reference area (n = 7) in the non-navigated group, whereby all corrections were within the desired range in the navigated group. There were no significant differences in operation time. This study showed that the use of a navigation system can not increase the precision of the open-wedge HTO procedure in patients with varus osteoarthritis but it can eliminate the outliers of a well defined range. Case-control study, Retrospective comparative study, Level III.

PROXIMAL TIBIAL OSTEOTOMY: STABILIZATION OF THE MEDIAL OPENING WITH A TRICORTICAL ILIAC BONE GRAFT

Objective: Radiographic assessment of lower limb alignment, in the frontal and sagittal planes, after high tibial osteotomy. To stabilize the osteotomy, a tricortical iliac graft was used, along with a positioning screw. Methods: Prospective study on 46 patients with ages ranging from 17 to 61 years. Among them, 42 patients presented genu varum secondary to knee osteoarthritis and four from other causes. Teleradiography was performed for surgical planning, using the Frank Noyes method, as modified by Fugizawa. A conventional surgical access of 3 cm was made to harvest a tricortical iliac graft. Osteotomy was performed under radioscopic control, by means of an anteromedial incision of 3 cm with release of the superficial portion of the medial collateral ligament. The graft was placed in the posterior portion of the osteotomy, to maintain an unaltered tibial slope. The screw crossed the osteotomy orthogonally to protect the lateral cortex. Pre and postoperative radiographic criteria were established to assess the results. Results: There was consolidation in 100% of the cases and maintenance of the mechanical axis, obtained intraoperatively, in 94% of the cases. The posterior slope of the tibial plateau in the sagittal plane ranged from 7° to 12°. Joint mobility was restored in all the patients. Eleven patients presented temporary pain at the site of graft harvesting, but none had paresthesia. The incidence of complications was 8% (infection, loss of correction and joint fracture). Conclusion: The technique was shown to be reproducible, simple, biological, accurate and low-cost, and it may be an alternative to the existing techniques.

The axis-board: An alternative to the cable technique for intraoperative assessment of lower limb alignment

Accurate intraoperative assessment of lower limb alignment is crucial for the treatment of long bone fractures, implantation of knee arthroplasties and correction of deformities. The aim of this study is to present a new technique for the intraoperative analysis of the mechanical axis. The axis board is placed under the patient's lower limb. With the centre of the ankle and hip lying on the reference line we can assess the mechanical axis of the lower limb. This technique was used in 38 cases (19 high tibial osteotomies, 13 femoral fractures and 6 tibial fractures). Comparing the intraoperative tibiofemoral angles and Mechanical Axis Deviations (MAD) with the results of the postoperative long standing radiographs we showed an accuracy of 1 +/- 0.9 degrees and 2.9 +/- 2.6 mm respectively. The method is a simple and convenient option for intraoperative evaluation of the mechanical axis. However, for complex corrections we still recommend the use of navigation systems.

Osteotomia proximal da tíbia: estabilização da abertura medial com enxerto tricortical de ilíaco

OBJETIVO: Avaliacao radiografica do alinhamento do membro inferior, nos planos frontal e sagital, apos osteotomia alta da tibia. Para estabilizacao da osteotomia foi utilizado enxerto tricortical de iliaco e parafuso de posicionamento. METODOS: Estudo prospectivo envolvendo 46 pacientes com idade entre 17 e 61 anos, sendo 42 portadores de geno varo secundario a osteoartrose e quatro por outras causas. A telerradiografia foi realizada para planejamento cirurgico, utilizando o metodo de Frank Noyes modificado por Fugizawa. Foi realizado acesso cirurgico convencional de 3cm para retirada do enxerto tricortical de iliaco. A osteotomia foi realizada sob controle de radioscopia, por incisao anteromedial de 3cm com liberacao da porcao superficial do ligamento colateral medial. O enxerto foi colocado na porcao posterior da osteotomia, para manter inalterado o slope tibial. O parafuso cruzou a osteotomia ortogonalmente para proteger a cortical lateral. Foram estabelecidos criterios radiograficos pre e pos-operatorios para avaliacao dos resultados. RESULTADOS: Houve consolidacao em 100% dos casos e manutencao do eixo mecânico, obtido no intraoperatorio, em 94%. A inclinacao posterior do plato tibial, no plano sagital, variou entre 7o e 12o. A mobilidade articular foi restabelecida em todos os pacientes operados. Onze pacientes apresentaram dor temporaria no local da retirada do enxerto; no entanto, nenhum apresentou parestesia. A incidencia de complicacoes foi de 8% (infeccao, perda da correcao, fratura articular). CONCLUSAO: A tecnica mostrou-se reprodutivel, simples, biologica, precisa e com baixos custos, podendo ser uma alternativa as tecnicas ja existentes.

Assessment of Lower Limb Alignment: Supine Fluoroscopy Compared with a Standing Full-Length Radiograph

While a full-length standing anteroposterior radiograph of the lower extremity provides the best radiographic method for assessing limb alignment, other methods must be used intraoperatively. We have employed intraoperative fluoroscopy with use of an electrocautery cord to assess limb alignment in the supine patient. We retrospectively compared the measurements of lower limb alignment that were obtained with use of supine intraoperative fluoroscopy with those that were obtained with use of a full-length standing anteroposterior radiograph of the lower extremity. A single examiner compared 102 sets of supine fluoroscopy images and full-length standing anteroposterior radiographs of the lower extremity to assess mechanical axis deviation and the joint line convergence angle. For the intraoperative fluoroscopic examination, an electrocautery cord was positioned overlying the center of the femoral head and the tibial plafond and an anteroposterior radiograph of the knee was made. The effect of age, gender, diagnosis, body mass index, pelvic height difference, joint line convergence angle, and the magnitude and direction of malalignment (varus or valgus) on the discrepancy in the observed mechanical axis deviation with use of the two methods was assessed. The mean absolute difference between the two techniques was 13.4 mm for the measurement of mechanical axis deviation (p < 0.0001) and 2.8 degrees for the joint line convergence angle (p < 0.0001). The correlation coefficient (r) for the measurement of mechanical axis deviation with use of the two radiographic methods was 0.88. An increase in body mass index was associated with a greater magnitude of discrepancy in the measurement of mechanical axis deviation between the two techniques (p = 0.0014). Age, gender, pelvic height difference, and the direction of malalignment had no effect on the discrepancy in the measurement of mechanical axis deviation. Limbs with >2 cm of mechanical axis deviation and those with a joint line convergence angle of >3 degrees on the standing radiograph were significantly more likely to have >10 mm of discrepancy in the measurement of mechanical axis deviation with use of the two imaging techniques (p < 0.005). Intraoperative fluoroscopy with use of the electrocautery cord method is a useful tool for assessing lower limb alignment in patients with a normal body mass index and </=2 cm of mechanical axis deviation and </=3 degrees of joint line convergence angle on the standing anteroposterior radiograph. However, the results obtained with fluoroscopy should be interpreted with caution in patients who are obese or who have substantial residual mechanical axis deviation or pathologic laxity of the knee joint.