Reliability and accuracy of MRI scanogram in the evaluation of limb length discrepancy

The purpose of this study was to compare MRI scanogram with traditional radiographic methods for measurement of limb length. The authors hypothesized that MRI scanogram would be as reliable and accurate as radiographic scanogram in measurement of limb length without exposing patients to ionizing radiation. Twelve cadaveric femurs were measured using AP conventional radiographic scanogram, CT scanogram, MRI scanogram, and electronic caliper. Three orthopaedists performed two separate measurements using each technique. Intraobserver and interobserver variability was assessed for each of the three radiographic techniques. Accuracy was assessed by comparison of radiographic measurements to electronic caliper measurements of femur length. The reliability of all three radiographic limb length measurement techniques was excellent (ICC > 0.99). The accuracy of plain radiographic scanogram was slightly superior to CT scanogram and MRI scanogram. The mean absolute differences for radiographic, CT, and MRI scanograms compared with the gold standard, direct caliper measurement, were 0.52 mm, 0.68 mm, and 2.90 mm, respectively. All three scanogram techniques showed excellent reliability and accuracy. Radiographic scanogram remains the gold standard for leg length measurement. MRI scanogram is slightly less accurate compared with radiographic scanogram, but it does not use ionizing radiation. MRI scanogram merits clinical study and comparison with the traditional radiographic scanogram method for measurement of limb length.     

CT scanogram for limb length discrepancy in comminuted femoral shaft fractures following IM nailing

IntroductionLeg length discrepancy (LLD) following intramedullary nailing of femoral fractures is not uncommon. We designed a prospective study to evaluate the efficacy of routine postoperative computed tomography (CT) scanograms for evaluation of limb length discrepancy in patients with comminuted Winquist III or IV femoral shaft fractures treated with intramedullary nailing.MethodsThe study consisted of 15 patients with Winquist III and 13 with a Winquist IV femoral shaft fracture pattern with an average age of 37 years. The mechanisms of injury were motor vehicle collision (13), gunshot wound (12) and falls (three). All patients were treated with a statically locked intramedullary femoral nail (18 antegrade and 10 retrograde). A CT scanogram evaluated limb length in all patients. A discrepancy of greater than 20 mm was considered for correction during the same admission. An LLD of 15–20 mm was discussed with the patient extensively for correction.ResultsIn the 28 patients included in our study, the average limb length discrepancy was 9.1 mm with a range of ?43.5 mm short to 10.3 mm long. The LLD was less than 10 mm in 18 patients (64%), 10–15 mm in four patients (14%), 15–20 mm in three patients (11%) and more than 20 mm in three patients (11%). Measurement of discrepancy as small as 0.5 mm showed that 18 patients were fixed with shortening and in 10 patients the operated femur was longer. Tibia lengths were also evaluated separately. Though none of the tibiae had a previous fracture, only three patients (10%) had tibiae of equal length. In 13 patients, an unequal tibia partially corrected the LLD whilst in 12 it added to the discrepancy. Five patients with LLD of greater than 15 mm underwent correction.ConclusionsA postoperative scanogram in patients with comminuted femoral shaft fractures treated with intramedullary nailing is useful to evaluate LLD and allows for early intervention. The ideal length where correction is necessary remains unclear.     

Reliability of radiographic measurement of small intestinal length

OBJECTIVE: The capacity for absorption of nutrients after small intestinal resection is related to the remaining length of intestine, and short bowel syndrome has major implications. Accurate pre-operative determination of bowel length may be useful in conditions where further resection of small bowel is contemplated. The aim of this study is to evaluate the accuracy of small bowel length measured by barium follow-through (BaFT) examination. PATIENTS AND METHODS: Twenty-two patients underwent both intra-operative measurement of small bowel length, and BaFT examination where length was measured using an opisometer. RESULTS: The difference between operative and radiological measurement (mean +/- standard deviation: 15.7 +/- 16 9%) was least in those with the shorter small intestine (overall variation: r = 0.703, P < 0.01, regression coefficient: -0.118, intercept: 15.1). There was no difference in whether BaFT was performed pre or postoperatively. CONCLUSION: Assessment of small bowel length by BaFT radiography is accurate, particularly in those with shorter small bowel lengths.     

Measurement variance in limb length discrepancy: clinical and radiographic assessment of interobserver and intraobserver variability

The purpose of this study was to assess interobserver and intraobserver variability in the assessment of clinical and radiographic measurement of lower limb length discrepancy. Clinical measurements included direct measurement with a tape measure from anterior superior iliac spine (ASIS) to lateral malleolus and ASIS to medial malleolus as well as block measurement. Slit scanogram radiographic measurement was also evaluated. All three clinical measurements had excellent reliability, but the relatively large mean differences and the large 95% confidence intervals for clinical measurements limit the usefulness of these techniques. Slit scanogram measurement was the most reliable measurement technique. The intraobserver variance of direct slit scanogram measurement included intraclass correlation coefficient of 0.99, mean difference of 0.1 cm, and 95% confidence interval of 0.4 cm. Results were not influenced by patient age or body mass index. Slit scanogram measurement is the preferred method for assessment of limb length discrepancy. The direct slit scanogram measurement described in the text follows the mechanical axis line of the leg in the "at ease" standing position described by Paley. Direct measurement using a measuring tape on a full-length slit scanogram is more reliable than indirect measurement using horizontal lines drawn to a radiolucent ruler that is positioned by a technician, since direct measurement avoids errors due to nonparallel positioning of the limb relative to the ruler, and direct measurement also avoids errors due to non-horizontal lines drawn from standard bony landmarks to the ruler. The ideal radiographic measurement technique would have high reliability and accuracy and would minimize or eliminate radiation.     

Epiphysiodesis for limb length discrepancy: a comparison of two methods

A retrospective review of 42 patients from 1999 to 2008 with at least 1-year follow-up was performed. The type and location of epiphysiodesis, average operative time and hospital stay, complications, timing and the final limb length discrepancy (LLD) were recorded. Computer tomography scanograms and mechanical axis view with grids were done to assess LLD. Twenty-six patients underwent Canale type epiphysiodesis compared with 14 receiving Metaizeau screw epiphysiodesis. The average operation time for Canale type was 42 and 45 min for screw epiphysiodesis. In the Canale group, there was a mean reduction in 2.5 cm in LLD from 3.7 to 1.2 cm over an average follow-up of 2.1 years. There were 4 minor and 2 major complications with a 92 % success rate defined as achieving the desired discrepancy correction. In the screw epiphysiodesis group, the mean change was 1.8 cm from 3.2 to 1.4 cm, over 2.2 years with 2 minor and 2 major complications and a success rate of 85 %. Percutaneous epiphysiodesis by any method is a reliable, minimally invasive method with minimal morbidity and an acceptable complication rate when compared to a corrective osteotomy or an open Phemister-type epiphysiodesis. This study has led to our preference for the Canale method, which in our hands has fewer complications and is more successful at reaching the desired discrepancy correction.     

The whole leg radiograph: standing versus supine for determining axial alignment

The whole leg radiograph (WLR), the standard technique for determining axial alignment, is usually taken in a standing position, although some prefer the supine position. To determine the difference between these two positions, we performed a standing and a supine WLR in 20 patients with a varus alignment. We found an average of 2 degrees more varus deviation in the standing position than in the supine position.     

Lengthening of the humerus for upper extremity limb length discrepancy

We present a case of humeral lengthening for a limb length discrepancy of 7.7 cm due to proximal humeral growth arrest in a 12-year-old boy. Lengthening of 69 mm was achieved using the Wagner technique. Bone grafting was not required. Humeral lengthening may be performed for upper extremity limb length discrepancy with good results. Objectives of treatment must include protection of the radial nerve from traction injury and from entrapment in the osteotomy site. Elbow extension may be lost during lengthening, but in the adolescent age group, full return of elbow motion can be expected.     

An analysis of radiographic parameters comparison between lumbar spine latericumbent and full-length lateral standing radiographs

Background Context

The lumbar spine latericumbent and full-length lateral standing radiographs are most commonly used to assess lumbar disorder. However, there are few literatures on the difference and correlation of the sagittal parameters between the two shooting positions.

全髋关节置换术下肢不等长的处理

目的 探讨全髋关节置换术下肢不等长的处理方法。方法 1997年 7月～ 2000年 7月,将 44例接受单侧全髋关节置换术的患者作为研究对象;男 30例,女 14例。患者手术时年龄 42～ 80岁,平均 65.8岁。术前通过临床及对骨盆前后位 X线片的测量评估双下肢不等长的程度,然后利用模板预测髋臼及股骨假体的置入位置,估计股骨颈的截骨水平以维持双下肢等长。术中先标记并测量股骨近端至髋臼上方两标志之间的距离,而后在术前估计的位置进行股骨颈截骨。置入假体试模之后再次测量两标志之间的距离,最后通过调整股骨头假体颈部或头部长度进一步进行纠正。结果 术前患肢短缩 1.5～ 5.0 cm的 30例患者中,术后仅 4例患肢短缩或延长在 1.5～ 2.0 cm之间。术前双下肢等长 14例患者中,术后仅 1例患侧延长超过 1.0 cm。结论 通过术前测量评估,预测股骨颈截骨平面,术中定位测量,置入假体试模后再次测量,调整股骨头假体颈部及头部长度等方法,可以有效地避免全髋关节置换术带来的下肢不等长,同时也可纠正术前存在的下肢短缩现象。     

Vascular reconstruction using deep vein for limb length discrepancy in a child

Iatrogenic vascular injuries can result in claudication and limb length discrepancy in growing children. Traditional reconstruction has been performed with great saphenous vein as a conduit. We report the case of a 7-year-old boy with a symptomatic limb length discrepancy and vascular reconstruction using femoropopliteal vein. The use of deep vein as an autogenous conduit may facilitate reconstruction of iliofemoral arteries in preadolescent children, providing an excellent size match and an efficacious means of restoring normal blood flow.     

Results of screw epiphysiodesis for the treatment of limb length discrepancy and angular deformity

The purpose of this study was to evaluate the technique of screw epiphysiodesis for effectiveness, predictability, and reversibility. We reviewed the cases of our first 60 patients (105 physes) treated with percutaneous screw epiphysiodesis or hemiepiphysiodesis. All cases were followed up to maturity or screw removal if growth remained after full correction. A total of 30 patients underwent the procedure for limb length inequality. Final inequality was compared with the predicted epiphysiodesis effect. A total of 30 patients (66 physes) underwent screw hemiepiphysiodesis for the correction of angular deformity. The degree of correction per month was calculated, the reversibility of the procedure was analyzed, and complications were evaluated. In the length group, at the end of treatment, the final limb length difference in the femur averaged 0.15 cm (SD, +/-0.37 cm) from the epiphysiodesis effect predicted by using the multiplier method. In the tibia, this difference was 0.05 cm (SD, +/-0.57 cm). In the angular group, the average correction in the distal femur was 6.91 degrees (SD, +/-3.75 degrees) or 0.75 degrees per month (SD, +/-0.45 degrees per month). In the proximal tibia, the average correction was 3.88 degrees (SD, +/-3.57 degrees) or 0.37 degrees per month (SD, +/-0.34 degrees per month). In all 13 cases where the screws were removed at the time of angular correction with significant growth remaining, growth resumed. Complications were minor and were related to incorrect placement of screws or minor hardware irritation. Percutaneous screw epiphysiodesis is a reliable, minimally invasive method with reliable results in both length and angular correction, with minimal morbidity, and with an acceptable complication rate.     

U型钉方法矫治儿童下肢不等长和成角畸形

目的回顾总结北京儿童医院自1989年至2007年应用U型钉方法矫治儿童下肢不等长和成角畸形的体会。方法对于下肢成角畸形,以及由于肢体过度生长造成的肢体不等长,采用U型钉皮下置入方法（亦即Blount临时骺阻滞钉技术）。如果达到治疗效果,即时取出,如果暂时未达到治疗目的 ,需要在置入U型钉后1年左右暂时取出,3个月后重新置入,以避免损伤骨骺。结果共有16例患儿接受了临时骺阻滞技术的治疗。1例先天性单侧肢体过度生长,1例神经纤维瘤病合并单侧肢体过度生长,2例K-T综合征,2例Proteus综合征,4例重度双侧膝外翻,1例内生骨软骨瘤合并膝外翻畸形,2例外伤骺早闭造成的膝外翻,1例骨骺发育不良合并膝外翻,1例Blount＇s病,1例佝偻病合并膝内翻。2例U型钉脱出,无断裂现象,1例出现骨骺变形,1例在置钉位置出现软骨样组织增生,本组病例并发症的发生率为25%。结论骨骺未闭合之前的儿童存在生长发育的潜力,在这个时期的儿童如果患有肢体过度生长导致的肢体不等长,以及不同原因造成的下肢成角畸形,可以采用临时骺阻滞技术,依靠自身的生长发育能力,自动调节后予以矫治。该方法具有创伤小,近似微创,手术较为简单,效果良好的优点。但是,置入钉的数量、位置、体内维持的时间等问题还需要进一步观察和研究。     

Effect of anesthesia type on limb length discrepancy after total hip arthroplasty

A retrospective study of 132 patients (63 spinal anesthesia and 69 general anesthesia) undergoing total hip arthroplasty was performed by 4 fellowship-trained adult reconstructive surgeons to determine the influence of anesthesia type on postoperative limb length and medial offset. Limb length discrepancy occurred in 87.0% of patients who received regional anesthesia as opposed to 47.6% patients who had general anesthesia (P<.001). Differences in postoperative medial offset measurements between the 2 groups were not statistically significant. It was concluded that surgeons operating on patients who receive regional anesthesia should supplement intraoperative tests for assessing hip stability with meticulous preoperative templating to avoid overlengthening the operative limb.     

Sagittal plane deformity after temporary epiphysiodesis of the distal femur for correcting limb length discrepancy

BackgroundOutcome of the temporary epiphysiodesis procedure for limb length discrepancy (LLD) is commonly evaluated in the coronal plane. The purpose of this study was to investigate implant position and complications of the distal femur and patella in the sagittal plane after the temporary epiphysiodesis.MethodsWe retrospectively reviewed 27 patients with LLD who underwent temporary epiphysiodesis of the distal femur using staples (11 patients) or eight-plates (16 patients) between 2007 and 2015. The mean age was 9.7 years (range, 6.3–13.8) at the time of epiphysiodesis. The implants were removed after a mean period of 2.6 years (range, 0.8–4.8) from the epiphysiodesis. Correction amount of LLD was measured on anteroposterior long leg standing radiographs. Implant position, extension deformity of the distal femur (>5° from epiphysiodesis to removal of implant) and patella baja (the epiphyseal line midpoint method < 1.0) were evaluated using lateral knee radiographs.ResultsThe average correction amount of LLD was 17.4 mm (range, 2–34). The average implant position was 43.1% (range, 35–55) from the anterior edge of the distal femoral epiphysis. At removal surgery, 16 patients (59%) had extension deformity of the distal femur and 14 patients (52%) showed patella baja. There were significant correlations between implant position and extension deformity (r = −0.51, p < 0.01) and as well as between correction amount of LLD and patella baja (r = −0.64, p < 0.01).ConclusionAfter temporary epiphysiodesis for the treatment of LLD, extension deformity of the distal femur and patella baja occurred frequently. Anterior placement of the implants is associated with extension deformity of the distal femur. The implant should be placed in the center of distal femoral physis, not the center of femoral shaft. Excessive correction of LLD should be avoided due to a risk of patella baja.     

Lengthening of congenital limb length discrepancy using callotasis: early experience of the Hospital for Sick Children.

Seventeen patients were reviewed after callotasis lengthening for congenital limb length discrepancy. The average age at lengthening was 10.8 years. Length discrepancy before lengthening ranged from 4.5 cm to 12 cm for the leg, and 24 mm to 30 mm for the forearm. At completion of the lengthening process, all but one patient had their discrepancy corrected successfully. The difficulties encountered were classified into problems, obstacles and complications. All patients suffered from superficial infection, but in only one case did this become a complication, resulting in a residual femoral discrepancy of 2 cm. Of the other three patients who suffered a complication, one fractured through the newly formed bone. The fracture was treated conservatively. In two further femoral lengthenings, the fixator had to be exchanged under general anaesthesia because it had reached its maximum excursion. Callotasis appears to be a safe and reliable method for correcting congenital limb length discrepancy in children.