Femoral malrotation after surgical treatment of femoral shaft fractures in children: a retrospective CT-based analysis

Elastic Stable Intramedullary Nailing in Length Stable Versus Unstable Pediatric Femoral Shaft Fractures: A Comparison of Clinical, Radiographic, and Pedobarographic Outcomes

BACKGROUND

Pediatric diaphyseal femoral fracture (PDFF) is one of the most common injuries requiring hospitalization. Elastic stable intramedullary nailing (ESIN) is commonly used for PDFFs in ages 5 to 11. The optimal treatment method for length unstable PDFF is a subject of ongoing debate. This study aimed to compare clinical, radiographic, and pedobarographic outcomes of ESIN between length stable and unstable PDFF.

METHODS

We retrospectively reviewed patients undergoing ESIN treatment for isolated PDFF between 2016 and 2021. Exclusion criteria were (1) history of ipsilateral or contralateral lower extremity fractures, (2) highly comminuted or segmental fractures, (3) body weight >50 kg, and (4) comorbidities affecting bone quality, range of motion, or neurologic status. The patients were divided into 2 groups according to length stability. Clinical, radiographic, and pedobarographic data were then assessed to compare groups.

RESULTS

Twenty-five patients were included (17 length stable and 8 length unstable PDFF) with a mean age of 73.6±17.8 months. There was no significant difference between groups in age, side of injury, body weight, follow-up duration, and nail-canal diameter ratio. Mean deformity in the fracture site in the early postoperative x-rays was not significantly different between groups ( P =0.661). After a mean follow-up of 27.8±14.2 months (range, 12-67), there was no significant difference in mechanical axis deviation, distal femur joint orientation angle, or limb-length discrepancy in both groups. The pedobarographic assessment revealed that the length unstable group had a significantly higher external foot progression angle in the injured extremity (9.8°±6.9° vs. 1.3°±5.6°, P =0.031). However, the length stable group had no significant difference in the foot progression angle (4.9°±5° vs. 3°±4.3°, P =0.326). There was no significant difference in either group for other pedobarographic parameters.

CONCLUSION

ESIN is a safe and effective option for length-unstable PDFF, yet attention should be paid to the rotational alignment. Although significant external rotation deformity occurs in length-unstable PDFF, it has no implications for the other pedobarographic parameters.

LEVEL OF EVIDENCE

Level IV.

Paediatric femoral shaft fractures: an instructional review for the FRCS examination

This review presents the principal features of paediatric femoral shaft fractures including the contemporary management strategies and relevant supporting evidence. The article is an overview of information relevant to clinical practice, in addition to preparation for the FRCS (Orth) examination.

Paediatric Femoral Diaphyseal Fractures in a South Wales Tertiary Centre: An Account of Trend in Management and Complications Over 16 Years

Femoral shaft fractures in children have seen a number of interesting developments over the past 20 years. This is a retrospective cohort study looking into epidemiological and outcomes data of femoral shaft fractures in children treated at a tertiary centre in Wales from 2005-2021. Over a period of 16 years, there has been a significant increase in the number of rigid or elastic nailing and submuscular plating, coinciding with a dramatic reduction of external fixation for definitive treatment of diaphyseal femoral fractures. All patients above five years of age underwent operative fixation, with elastic or rigid intramedullary nailing the treatment of choice. Following multiple linear regression with 16 possible explanatory factors, this study found a statistically significant increase in time to union for open fractures, pre-operative translation, and operation time. Furthermore, there was a significant increase in post-operative leg length discrepancy for right versus left-sided fractures. Overall complication rates were 4% for minor and 8% for major complications. Complication rates were lowest for rigid intramedullary nailing and highest for external fixation. No cases of avascular necrosis were found for 27 rigid intramedullary nails inserted. Overall this study reports treatment choices and outcomes in keeping with current trends in management for paediatric femoral shaft fractures.

Ultra-low-dose computed tomography for torsion measurements of the lower extremities in children and adolescents

BACKGROUND

Quantifying femoral and tibial torsion is crucial in the preoperative planning for derotation surgery in children and adolescents. The use of an ultra-low-dose computed tomography (CT) protocol might be possible for modern CT scanners and suitable for reliable torsion measurements even though the bones are not completely ossified.

METHODS

This is a retrospective review of 77 children/adolescents (mean age 12.7 years) who underwent a lower extremity CT for torsion measurements on a 64-slice scanner. A stepwise dose reduction (70%, 50%, 30% of the original dose) was simulated. Torsion measurements were performed on all image datasets, and image noise, interrater agreement and subjective image quality were evaluated. Effective radiation dose of each original scan was estimated. As proof of concept, 24 children were scanned with an ultra-low-dose protocol, adapted from the 30% dose simulation, and the intra-class correlation coefficient (ICC) was determined. Ethics approval and informed consent were given.

RESULTS

Torsion measurements at the simulated 30% dose level had equivalent interrater agreement compared to the 100% dose level (ICC ≥ 0.99 for all locations and dose levels). Image quality of almost all datasets was rated excellent, regardless of dose. The mean sum of the effective dose of the total torsion measurement was reduced by simulation from 0.460/0.490 mSv (boys/girls) at 100% dose to 0.138/0.147 mSv at 30%. The ICC of the proof-of-concept group was as good as that of the simulated 30% dose level.

CONCLUSION

Pediatric torsion measurements of the lower extremities can be performed using an ultra-low-dose protocol without compromising diagnostic confidence.

Effect of rotational deformities after pediatric femoral fracture on clinical outcome

Femoral shaft fractures are the most common pediatric injuries that require hospitalization. Early closed reduction and spica casting are one of the most popular treatment options. One of the significant complications of spica casting is rotational deformities of the fracture. The present study aimed to determine the potential effects of rotational deformities in pediatric patients who underwent early spica casting after a femoral shaft fracture. Pediatric patients who underwent early spica casting following femoral shaft fractures were screened retrospectively. Radiological measurements were made on the patients' initial postop radiographs who could be measured rotationally according to the defined radiological method. Twenty-three patients with more than 10° of rotation in their measurements were included in the study. Differences in leg length and rotation between both legs were calculated with clinical examination methods for all patients in the study. The gaits of the patients were observed; patient and family complaints were obtained. We found a strong and positive correlation between the rotational measurement made on the X-ray and the clinical measurement (R: 0.634, P: 0.001). For measurements made on X-ray, the mean rotational value was calculated as 27.2 ± 6.9 degrees. After the patients' clinical examination, an average of 3.0 ± 1.7 degrees rotational difference was found between the broken limb and the healthy limb. No patient or family complained of trauma. Early spica casting, according to the age of the patient, is an effective treatment method. There may still be certain degrees of deformity after treatment, but patients well tolerate them even at high degrees. Accordingly, it was concluded that the rotational deformities less than 30 degrees would not cause clinical problems on children under 4 years of age which may require postoperative revisions or the use of various costly imaging techniques and include radiation.

Radiographic cortical thickness parameters as predictors of rotational alignment in proximal tibial shaft fractures: a cadaveric study

AIM

The treatment of tibial fractures with an intramedullary nail is an established procedure. However, torsional control remains challenging using intraoperatively diagnostic tools. Radiographic tools such as the Cortical Step Sign (CSS) and the Diameter Difference Sign (DDS) may serve as tools for diagnosing a relevant malrotation. The aim of this study was to investigate the effect of torsional malalignment on CSS and DDS parameters and to construct a prognostic model to detect malalignment.

METHODS

A proximal tibial shaft fracture was set in human tibiae. Torsion was set stepwise from 0° to 30° in external and internal torsion. Images were obtained with a C-arm and transferred to a PC for measuring the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD) in AP and the anterior cortical thickness (ACT) as well as the posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and the distal main fragment.

RESULTS

There were significant differences between the various degrees of torsion for each of the absolute values of the examined variables. The parameters with the highest correlation were TD, LCT and ACT. A model combining ACT, LCT, PCT and TD lateral was most suitable model in identifying torsional malalignment. The best prediction of clinically relevant torsional malalignment, namely 15°, was obtained with the TD and the ACT.

CONCLUSION

This study shows that the CSS and DDS are useful tools for the intraoperative detection of torsional malalignment in proximal tibial shaft fractures and should be used to prevent maltorsion.

The clinical features, management options and complications of paediatric femoral fractures

This article discusses the incidence, applied anatomy and classification of paediatric femoral fractures based on critical appraisal of the available evidence. The aim is to identify techniques that are relevant to contemporary practice whilst excluding the technical details of individual procedures that are beyond the scope of this review. Injuries of the proximal, diaphyseal and distal segments are considered individually as there are considerations that are specific to each anatomical site. Femoral neck fractures are rare injuries and require prompt anatomical reduction and stable fixation to minimise the potentially devastating consequences of avascular necrosis. Diaphyseal fractures are relatively common, and there is a spectrum of management options that depend on patient age and size. Distal femoral fractures often involve the physis, which contributes up to 70% of femoral length. Growth arrest is common consequence of fractures in this region, resulting in angular and length-related deformity. Long-term surveillance is recommended to identify deformity in evolution and provide an opportunity for early intervention. Deliberate injury should be considered in all fractures, particularly distal femoral physeal injuries and fractures in the non-walking child.

Intraoperative torsion control using the cortical step sign and diameter difference in tibial mid-shaft fractures

AIM

Intramedullar nailing of tibial mid-shaft fractures is a common surgical treatment. Fracture reduction, however, remains challenging and maltorsion is a common discrepancy which aggravates functional impairment of gait and stability. The use of radiographic tools such as the cortical step sign (CSS) and the diameter difference sign (DDS) could improve fracture reduction. Therefore, the validity of the CSS and DDS was analyzed to facilitate detection of maltorsion in tibial mid-shaft fractures.

METHODS

Tibial mid-shaft fractures were induced in human cadaveric tibiae according to the AO classification type A3. Torsional discrepancies from 0° to 30° in-/external direction were enforced after intramedullary nailing. Fluoroscopic-guided fracture reduction was assessed in two planes via analysis of the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD), anterior cortical thickness (ACT), posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and distal fracture fragment.

RESULTS

The TD, LCT and ACT have shown a highly significant correlation to predict tibial maltorsion. While a model combining ACT, LCT, PCT and TD lateral was most suitable model to identify tibial maltorsion, a torsional discrepancy of 15°was most reliably detected with use of the TD and ACT.

CONCLUSION

The present study has shown, that maltorsion can be reliably assessed by the CSS and DDS during fluoroscopy. Thus, torsional discrepancies in tibial mid-shaft fractures can be most reliably assessed in the lateral plane by analysis of the LCT and TD.

Decreased Radiation Exposure Using Ultrasound-Assisted Reduction and Fixation of Femoral Shaft Fractures in Children: A Pilot Study

Elastic stable intra-medullary nail procedures have been used to treat femoral fractures in children for some time. Radiation exposure generated by intra-operative radioscopy may induce side effects in children and staff. This study introduces a method of ultrasound-assisted reduction and fixation of femoral fractures in children to decrease radiation exposure. We included 21 children and evaluated displacement of fractures using multi-section scanning. All fracture reductions were performed with ultrasonography. A hyperechoic point with a posterior acoustic shadow can be seen under the proximal and distal segments after the nail passes through the fracture site. Comparison with radioscopy suggests that this is a viable method of reduction and fixation of femoral shaft fractures in children, and can effectively decrease radiation exposure.

Quantitative assessment of changes in lesser trochanter shapes in relation to femoral rotations

OBJECTIVE

The aim of this study was to evaluate changes in lesser trochanter shapes in relation to femoral rotations and to develop a reference value for the determination of clinically relevant malrotation of the femur.

METHODS

Patients who underwent computed tomography angiography between January 2009 and July 2018 were identified based on a review of their institutional medical records. Thereafter, three-dimensional (3D) images of the whole femur for a total of 860 patients were obtained from their tomographic sections. The distance between the lateral outer cortex of the femur and the most medial point of the lesser trochanter with the femur in neutral rotation was measured and set as the reference value. Then, the same distance was measured at 5°, 10°, 15°, and 20° of femoral internal rotation and at 5°, 10°, 15°, 20°, and 25° of femoral external rotation. To avoid magnification errors, the reference values were divided by each measured value at these different rotation angles and then multiplied by 100.

RESULTS

The mean distances between the lateral cortex and the most medial point of the lesser trochanter at 5°, 10°, 15°, and 20° of femoral internal rotation were 97%, 93%, 90%, and 88%, respectively, of those measured with the femur in neutral rotation. The same distances at 5°, 10°, 15°, 20°, and 25° of femoral external rotation were 102%, 104%, 106%, 107%, and 108%, respectively, of those measured with the femur in neutral rotation. There was no statistically significant difference between the measured distances in males and females (p>0.05). However, significant differences were observed among each measured distance at different angles of femoral rotation (p<0.01).

CONCLUSION

The surgeon should be aware of the possible femoral malrotation if the distance between the lateral cortex of the femur and the most medial point of the lesser trochanter on the operated side is more than 106% or less than 90% of that measured with the femur in neutral rotation on the healthy side.

LEVEL OF EVIDENCE

Level IV, Diagnostic study.

The rotational fixator: A new device

Objectives

Malrotation after surgical treatment of femoral shaft fractures is a common problem and often leads to follow-up procedures with uncertain outcome. The aim of this study is the validation of a new device (Rotational Fixator) to perform the correction safely and accurately.

Methods

In an in-vitro study, we tested the Rotational Fixator on 21 corpse bones against a commercially available standard goniometer for measurement inaccuracies. For this purpose, we varied the rotation width from 10 to 30° in inside and outside rotation.

Results

We found a small measurement inaccuracy of 1-2° with increasing rotation. The smallest differences are found at 10° IR with 0.9524° (SD ± 1.0713; p = 0.001) difference and 10° ER with at 0.5952° (SD ± 0.6823; p = 0.001) difference and increase up to 30° (IR 1.6667°, SD ± 1.7121, p < 0.000/ER 1.5000°, SD ± 1.0488, p < 0.000).

Conclusions

The measurement results of the device show a constant deviation from the gold standard but are constant in the measurement error and slightly in relation to the desired correction range, so that a further review of the device and further testing in in vivo studies makes sense.

Levels of evidence

Level 3.

[Torsion and torsional development of the lower extremities]

BACKGROUND

Torsion is a frequent reason for consultation in paediatric orthopaedics. Torsion of the femur and the tibia in children change during growth. Depending on the age and possibility for compensation, this can be reflected in the gait pattern. Different causes can affect the normal development of torsion.

DIAGNOSTICS

In the context of paediatric orthopaedic assessment, the distinction between physiological and pathological torsion is essential. In addition to the patient history and observation of the gait pattern, as well as a detailed clinical examination, additional imaging techniques are used (Rippstein/Dunn, torsional CT/MRI, EOS). The dynamic effect of abnormal torsion on gait is evaluated by instrumented 3D gait analysis.

PATHOGENESIS

Evidence for the long-term significance of torsional deviations and the risk of consequential damage are low. Isolated increased femoral anteversion without accompanying hip dysplasia is fundamentally harmless, corrects during growth and only rarely needs correction in the case of ongoing disturbing gait or knee problems. In contrast, retroversion is likely indicate the development of pre-arthritic deformity and should be observed and treated more carefully. Tibial torsion shows great variability and may influence the development of femoral torsion. Torsional deformities in children with neurological or syndromal conditions are differentiated as when the biomechanical effects of torsions on their gait function are generally more marked and therefore treatment is more frequently necessary.

THERAPY

Conservative treatments cannot be expected to have an effect on the condition of the bones. Correction can only be achieved surgically with a rotational osteotomy. A simple principle underlies the technique, whereas indication and timing are challenging.

Comparison of efficacy between internal fixation of minimally invasive elastic stable intramedullary nail and plate in the treatment of pediatric femoral shaft fracture

Objective:

To compare and analyze the clinical effects of internal fixation of minimally invasive elastic stable intramedullary nail and plate in the treatment of pediatric femoral shaft fracture.

Methods:

A total of 120 children with femoral shaft fractures who were admitted to our hospital from December 2016 to April 2018 were enrolled. The children were divided into an observation group and a control group by random number table, with 60 children in each group. The children in the observation group underwent internal fixation of minimally invasive elastic stable intramedullary nail, while those in the control group underwent open reduction based on internal fixation of plate. The surgical status and postoperative complications of the two groups were observed and compared, and Kolmert knee function scoring criteria were used for assessing the surgical effects of children.

Results:

The operation duration, intraoperative blood loss, hospitalization duration, fracture healing time and time of off-bed loaded activity of the observation group were significantly shorter than those of the control group, and the differences were statistically significant (P<0.05). The excellent and good rate of fracture healing in the observation group was 100%, which was higher than that of the control group, 83.33%, and the difference was statistically significant (P<0.05). The total incidence rate of complications in the observation group was 8.33%, which was lower than that of the control group, 10.00%, but the difference was not statistically significant (P>0.05).

Conclusion:

Pediatric femoral shaft fractures can be treated with internal fixation of minimally invasive elastic intramedullary nail, and it has advantages of significant curative effect, small trauma and fast postoperative recovery, which is conducive to fracture healing and worth promoting.

Radiographic cortical thickness parameters as predictors of rotational alignment in proximal femur fractures: A cadaveric study

Radiographic assessment tools such as the cortical step sign (CSS) or the diameter difference sign (DDS) aim to identify clinically relevant rotational malalignment after long bone fracture fixation. We aimed to analyze the effect of rotational malalignment on CSS and DDS parameters in a subtrochanteric fracture model and to construct a prognostic model to identify clinically relevant rotational malalignment. A subtrochanteric transverse osteotomy was set in human femora. Rotation was set stepwise from 0° to 30° in internal and external rotation. Images were obtained using a C-arm and transferred for measuring the medial cortical thickness (MCT), lateral cortical thickness (LCT), femoral diameter (FD) in AP and the anterior cortical thickness (ACT) as well as the posterior cortical thickness (PCT) and the FD of the proximal and the distal main fragment. There were significant differences between the various levels of rotation for each of the absolute values of the evaluated variables. MCT, PCT and FD (AP & lat.) were the most affected parameters. In internal rotation, the MCT, PCT and the FD were the most affected variables. The parameters with the highest correlation with femoral rotation were ACT, PCT and FD. A model combining ACT, LCT, PCT and FD AP was most suitable model in identifying rotational malalignment. The best prediction of clinically relevant rotational malalignment was obtained with the FD and the PCT. The CSS and the DDS are promising tools for detecting rotational deformities of the proximal femur and should be used intra- and postoperatively. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.