Validity and reliability of existing and modified clinical methods of measuring femoral and tibiofibular torsion in healthy subjects: use of different reference axes may improve reliability

Concurrent Validity of Three Photogrammetric Methods for Assessing Knee Alignment in Sagittal Plane

Background: Evidence supporting the validity of photogrammetry for assessing body segment alignment remains limited, with most studies focusing on spinal evaluation. Thus, there is a lack of robust research examining its use for other body segments such as the lower limbs. Objective: This study aimed to evaluate the concurrent validity of three photogrammetric methods for measuring knee alignment in the sagittal plane with and without corrections for potential rotational deviations in the participant's thigh and leg. Methods: A total of 21 adults underwent sequential evaluations involving panoramic radiography of the lower limbs and photogrammetry at a private radiology clinic. Photogrammetric analysis involved identifying the following anatomical landmarks: the greater trochanter of the femur (GTF), the lateral condyle of the femur (LCF), the head of the fibula (HF), and lateral malleolus (LM). Three photogrammetric methods were employed: (1) the condylar angle (CA) defined by the GTF, LCF, and LM points; (2) the fibula head angle (FHA) defined by the GTF, HF, and LM points; and (3) the four-point angle (4PA) incorporating the GTF, LCF, HF, and LM. Concurrent validity was assessed using correlation analysis, agreement with radiographic measurements, and the root mean square error (RMSE). Each photogrammetric method was tested using raw (CA, FHA, and 4PA) and corrected (CAcorr, FHAcorr, and 4PAcorr) values, accounting for thigh and/or leg rotational deviations. Results: Correcting for thigh and leg rotations significantly improved the validity metrics for all methods. The best performance was observed with the corrected condylar angle (CAcorr: r = 0.746; adjusted r2 = 0.533; RMSE = 2.9°) and the corrected four-point angle (4PAcorr: r = 0.733; adjusted r2 = 0.513; RMSE = 3.0°); however, the measurements presented proportional errors, possible due the method of assessment of rotations. Conclusions: The findings validate the evaluated photogrammetric methods for assessing sagittal knee alignment. Accounting for thigh and leg rotational deviations is critical for achieving accurate measurements, raising the need of accurate tools for measuring rotational changes in the lower limbs to avoid errors.

Femoral anteversion as a potential risk factor for anterior cruciate ligament injuries in athletes

Purpose

Non-contact anterior cruciate ligament (ACL) injuries are influenced by the anatomic and biomechanical characteristics of the lower limb. The combination of knee valgus, hip internal rotation and tibial external rotation are important contributors to non-contact ACL injuries. In this study, we aimed to evaluate the effect of femoral anteversion on the incidence of ACL injuries among athletes.

Methods

A retrospective comparative study was conducted on 137 adult male athletes with high suspicion of ACL injury following a sports-related injury. The patients were classified into two groups based on the presence of ACL tears: the 'ACL tear' and the 'ACL intact' groups. The femoral anteversion angle was measured by both a computed tomography (CT) scan using the method described by Hernandez et al. and a physical examination using Craig's test. The association of ACL tears with femoral anteversion angle was evaluated. Femoral anteversion cut-off values were calculated to find the best margin for a high probability of ACL tearing.

Results

The mean anteversion in patients with ACL tears was found to be higher compared to ACL-intact patients both in CT scan measures (18.4 ± 5.5 vs. 12.9 ± 6.9, p value < 0.001) and physical examination (20.2 ± 5.9 vs. 14.8 ± 7.7, p value < 0.001). The correlation analysis revealed an excellent correlation between femoral anteversion measured by CT scan and Craig's test results (r = 0.94). Cut-off values for femoral anteversion measured by CT scan concerning ACL tearing with the highest sensitivity and specificity were 12.7 and 19.0, respectively. The Craig-measured cut-off values were 1.5-2° more than the CT scan measurements.

Conclusion

This study reveals a significant correlation between increased femoral anteversion and a higher risk of ACL injury among male athletes. The results of this study aid in designing personalized prevention programmes for non-contact ACL injuries among athletes.

Level of Evidence

Level III.

Assessing Femoral Anteversion in Patients With Bilateral Recurrent Patellar Dislocations

Background

After first-time lateral patellar dislocation, 44% to 70% of patients sustain redislocations. Increased femoral anteversion (FA) is considered to result in increased lateralizing forces on the patella, which might predispose one to patellar instability. When recurrent patellar dislocations (RPDs) are bilateral, it is unclear if the FA is even more increased.

Hypothesis

Patients with bilateral RPD would have greater FA than patients with unilateral RPD.

Study Design

Case-control study; Level of evidence, 3.

Methods

A total of 52 skeletally mature patients with RPD and a clinical suspicion of rotational malalignment underwent rotational computed tomography or magnetic resonance imaging. The uni- or bilaterality of the RPD was determined. A control group comprising 54 adult patients with trauma underwent computed tomography of both lower extremities as part of a multitrauma protocol. The FA values of both lower extremities were evaluated separately.

Results

In total, 20 of 52 (38.5%) patients in the study group had a history of unilateral RPD and 32 of 52 (61.5%) patients had a bilateral RPD diagnosis. The mean FA of the asymptomatic limb in unilaterally symptomatic patients was 18.0° (SD, 11.2°; range, 0.5°-40.0°; median, 16.5°). In the symptomatic limb, the mean FA was 19.2° (SD, 9.1°; range, 2.0°-33.0°; median, 19.0°) (mean difference, 1.2°; 95% CI -1.3° to 3.8°). In bilaterally symptomatic patients, the mean FA on the right side was 23.2°, and 22.5° on the left. The mean differences between the symptomatic limbs in the unilateral RPD group and the right or left limbs in the bilateral RPD group were 4.0° (P = .263) and 3.3° (P = .326), respectively. In the control group without RPD, the mean FA was 12.5° (SD, 8.5°; range, 0.8°-33.0°; median, 10.9°). The mean difference between right limbs of the patients with bilateral RPD and right limbs of controls was 10.8° (P = .001).

Conclusion

Patients with bilateral RPD have bilaterally greater FA than patients without a history of RPD. Patients with unilateral RPD have greater FA on both sides compared with the control group without a history of lateral patellar dislocation. No statistically significant difference of FA can be seen between patients with bilateral or unilateral RPD.

Predicting two-year return-to-sport failure after medial patellofemoral ligament reconstruction in patellar dislocation patients with bone abnormalities

PURPOSE

To develop a comprehensive and validated personalized scoring system based on anatomical characteristics to predict the probability of failure to return to sport after medial patellofemoral ligament reconstruction in patients with patellar dislocation.

METHODS

312 patients with medial patellofemoral ligament reconstruction in our hospital from 2013 to 2023 were included. Demographic and anatomical characteristics were collected retrospectively. A backward stepwise approach was used to identify independent predictors, and a nomogram was constructed to predict the probability of recurrence. The predictive performance was evaluated by receiver operating characteristic curves, calibration diagram and decision curve analysis.

RESULTS

Multivariate analysis showed that increased tibial tubercle-trochlear groove (TT-TG) distance, trochlear dysplasia, increased femoral anteversion angle, and patellar alta were independent risk factors for failure of return to sport after medial patellofemoral ligament reconstruction. Validation of this column graph in the training cohort and validation cohort showed strong predictive power, with areas under the curve of 0.850 and 0.844, respectively. The nomogram has good calibration and good clinical practicability.

CONCLUSION

The study developed a personalized predictive nomogram with 4 predictors (increased TT-TG distance, trochlear dysplasia, increased femoral anteversion angle, and patellar alta) that allowed surgeons to stratify the risk of failure to return to sport after medial patellofemoral ligament reconstruction and recommend skeletal surgery for patients with these factors.

LEVEL OF EVIDENCE

Level III.

Validity and reliability of ultrasonographic assessment of femoral and tibial torsion in children and adolescents: a systematic review

Torsional disorders of the lower limb are common in childhood, and they are one of the primary reasons parents seek consultation with healthcare providers. While clinical manoeuvres can assess femoral and tibial torsion, their reliability is medium to low. Various imaging-based techniques, including computed tomography, magnetic resonance imaging, fluoroscopy, biplanar radiology and ultrasonography, have been used to evaluate torsional alterations of the lower extremity. Among these, ultrasound assessment offers certain advantages: it is a low-cost, non-irradiating technique, which allows the follow-up of children's torsional development. However, to the best of the authors' knowledge, its validity and reliability have not been summarised in a systematic review. This study aims to analyse the validity and reliability of ultrasonography in determining femoral and tibial torsion in children and adolescents. A search from Medline (via PubMed), Web of Science, Scopus and CINAHL databases were performed from inception to 16 March 2023. No restrictions were placed on the publication year or language. The methodological quality of all eligible studies was independently reviewed by two authors using QUADAS and STARD checklists. Overall, 1546 articles were identified through the searches; 30 were considered eligible for full-text screening; and 8 studies were finally included in this review. The included studies were conducted in Germany, Norway and the UK. Among them, 7 studies analysed the validity of ultrasonography compared with other imaging techniques such as computed tomography, magnetic resonance imaging and biplanar X-ray, and 4 studies assessed intra- and inter-observer reliability. All the studies assessed femoral torsion, but only one of them also included tibial torsion.     Conclusion: Ultrasound is a good alternative for routine evaluation and follow-up of femoral torsional alterations in children and adolescents due to its safety, accessibility and immediate results in the clinical examination room. Although ultrasound has good accuracy and reliability for routine evaluations, there is controversy about whether it is sufficient for surgical planning. In cases where greater accuracy is required, magnetic resonance imaging and biplanar radiography are the preferred imaging techniques. What is Known: • Several imaging-based techniques have been described for the assessment of torsional alterations of the lower extremity. • Computed tomography, magnetic resonance imaging, biplanar radiology and ultrasonography are the most used and studied methods. What is New: • Ultrasonography represents a good alternative for the assessment of femoral and tibial torsional alterations in children and adolescents, given its safety, accessibility and immediacy of results in the consultation room. • Its accuracy and reliability are good but not sufficient for surgical planning, in which case MRI and biplanar X-ray will be the preferred choices.

A new method for assessing tibial torsion using computerized tomography in a pediatric population

Purpose

Tibial torsion disorders may lead to abnormal gait, frequently leading to a consultation with a pediatric orthopedic surgeon. The present study evaluated an alternative method for assessing tibial torsion on computerized tomography (CT) images that considers the tibial distal axis to be equivalent to the geometric axis of the tibiotalar joint.

Methods

One hundred CT scans were reviewed retrospectively, and four measurements were taken: proximal transtibial angle (PTTA), posterior margin tibial plateau angle (PMTPA), intermalleolar angle (IMA), and talar angle (TA). The tibial torsion angle was then calculated using these different angles.

Results

The patient cohort comprised 38 girls and 62 boys, with a mean age of 12 ± 4.4 years. Median PTTA and PMTPA were -8.4° ± 14.7° and -8.8° ± 14.2°, respectively, with no statistically significant difference. Mean IMA and TA were 23° ± 16.2° and 17.2° ± 16.9°, respectively, with a statistically significant difference. Mean total measurement time per patient was 6'44", with means of 2'24" for PTTA, 36" for PMTPA, 2'14" for IMA, and 1'12" for TA.

Conclusion

Tibial torsion values may differ significantly depending on the axis chosen to define tibial orientation. At the level of the proximal tibia, the choice of PTTA or PMTPA had little influence on the calculation of the tibial torsion angle. There was a significant difference of 5.8° when measuring the distal tibia. Measuring the PMTPA and TA is probably more suited for use in clinical practice because their tracing is simple and faster.

Effects of differences in femoral anteversion and hip flexion angle on hip abductor muscles activity during clam exercise in females

This study aimed to determine differences in the hip abductor muscle activity during clam exercise at different hip flexion and femoral anteversion angles. Thirty healthy females were divided into two groups based on the femoral anteversion angle: the excessive femoral anteversion group and the normal group. Clam exercise was performed at three different hip flexion angles (60°, 45°, and 30°). Tensor fascia latae, gluteus medius, and superior portion of gluteus maximus activities were measured during the exercise, and the results were normalized to the activity during maximum voluntary isometric contraction to calculate the gluteal-to-tensor fascia latae muscle activation index. The superior portion of gluteus maximus activities at a hip flexion of 60° and 45° were greater than that at 30°. The excessive femoral anteversion group had a lower gluteal-to-tensor fascia latae muscle activation index than the normal group; the gluteal-to-tensor fascia latae muscle activation index for hip flexion at 60° was higher than that at 45°, and the gluteal-to-tensor fascia latae muscle activation index for hip flexion at 60° and 45° were higher than that at 30°. Therefore, the femoral anteversion angle and hip joint position were related to the activity of the hip abductor muscles during clam exercise. These findings may provide a rationale for instructing exercises to maximize the activity of the hip abductor muscles in individuals with an excessive femoral anteversion angle.

Predicting the Probability of Recurrence Based on Individualized Risk Factors After Primary Lateral Patellar Dislocation Treated Nonoperatively

PURPOSE

To develop a comprehensive and effective personalized scoring system on the basis of demographic and clinical characteristics for predicting recurrence probability in patients with primary lateral patellar dislocation (LPD).

METHODS

Participants included 261 primary patients with LPD with 2-year minimum follow-up from our hospital across 2013 to 2020. Demographic and clinical characteristics were collected retrospectively. The backward stepwise method was performed to identify independent predictors and construct a nomogram to predict the probability of recurrence. The predictive performance was assessed by receiver operating characteristic curves, calibration plots, and decision curve analysis.

RESULTS

After variables selection, 6 independent predictors of recurrence (skeletal maturity, trochlear dysplasia, tibial tuberosity-trochlear groove distance, mechanical axis deviation, Insall-Salvati index, and patellar tilt) were enrolled in our model. Validation of this nomogram in both training and validation cohort revealed powerful predictive ability, with an area under the curve of 0.962 and 0.977, respectively. The nomogram also showed great calibration and good clinical practicability.

CONCLUSIONS

Our study presented a nomogram that incorporates 6 independent risk factors (skeletal maturity, trochlear dysplasia, tibial tuberosity-trochlear groove distance, mechanical axis deviation, Insall-Salvati index, and patellar tilt), which can be conveniently used to accurately predicts the risk of recurrence after primary LPD in individual cases.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic study.

Validity of measurement of femoral anteversion angle using FEMORA® software based on two-dimensional radiographic imaging examination femur in children with cerebral palsy in Indonesia

Introduction

Children with spastic cerebral palsy (CP) often show an increase in femoral anteversion angle (FAA). Computed tomography (CT) scan is the main modality for evaluating FAA in these patients, however, due to significant radiation exposure, it carries a high carcinogenic risk. FEMORA® software is expected to be able to accurately assess FAA even with conventional X-ray images that only require low radiation exposure. However, its validity has not been tested in various populations or CT devices. This study aimed to validate the FEMORA® software by comparing it to CT scans done on an Indonesian population.

Material and methods

All spastic CP patients of the outpatient clinic at Dr. Soetomo Hospital between March and November 2022, were included. The FEMORA® Software evaluation was performed by three examiners. The calculation results were averaged and compared with those of the CT scan. Intraclass correlation coefficient (ICC), reliability, and correlation were be assessed.

Results

There were 36 patients included in this study. Most were female (n = 22; 61,1 %) and the average age was 7,28 years old. Interobserver preoperative analysis using ICC showed good outcomes (p = 0.918; 95 % CI, 0.858-0.955). FAA measurement results using FEMORA® and CT scans were 41,71 ± 12,90 and 32,68 ± 11,85, respectively. Correlation coefficient between the two values is 0.634 (p < 0.001).

Conclusion

FEMORA® software demonstrates a good and significant correlation with FAA measurement using CT scan.

Analysis of lower extremity alignment (LEA) in children with recurrent patellar dislocation by EOS system

Objectives

Recurrent patellar dislocation (RPD) greatly affects active young individuals, necessitating the identification of risk factors for a better understanding of its cause. Previous research has connected RPD to lower limb alignment (LEA) abnormalities, such as increased femoral anteversion, tibial external rotation, knee valgus, and flexion. This study aims to use EOS technology to detect RPD-related LEA anomalies, enabling three-dimensional assessment under load conditions.

Methods

A total of 100 limbs (50 in the RPD group, 50 in the control group) were retrospectively analyzed. In the RPD group, we included limbs with recurrent patellar dislocation, characterized by dislocations occurs at least two times, while healthy limbs served as the control group. We used EOS technology, including 2D and 3D imaging, to measure and compare the following parameters between the two groups in a standing position: Femoral neck shaft angle (NSA), Mechanical femoral tibial angle (MFTA), Mechanical lateral distal femoral angle (mLDFA), Medial proximal tibial angle (MPTA), Anatomical femoral anteversion (AFA), External tibial torsion (ETT), and Femorotibial rotation (FTR).

Results

The significant differences between the two groups were shown in NSA 3/2D, MFTA 3/2D, mLDFA 3/2D, MPTA 3D, AFA, FTR. No significant difference was shown in MPTA 2D, ETT between the RPD group and the control group. Further binary logistic regression analysis. Further binary logistic regression analysis was conducted on the risk factors affecting RPD mentioned above. and found four risk factors for binary logistic regression analysis: mLDFA (3D), AFA, NSA(3D), and FTR.

Conclusions

EOS imaging identified abnormal LEA parameters, including NSA, MFTA, mLDFA, MPTA, AFA, and FTR, as risk factors for RPD. Children with these risk factors should receive moderate knee joint protection.

The gait pattern and not the femoral morphology is the main contributor to asymmetric hip joint loading

Gait asymmetry and skeletal deformities are common in many children with cerebral palsy (CP). Changes of the hip joint loading, i.e. hip joint contact force (HJCF), can lead to pathological femoral growth. A child's gait pattern and femoral morphology affect HJCFs. The twofold aim of this study was to (1) evaluate if the asymmetry in HJCFs is higher in children with CP compared to typically developing (TD) children and (2) identify if the bony morphology or the subject-specific gait pattern is the main contributor to asymmetric HJCFs. Magnetic resonance images (MRI) and three-dimensional gait analysis data of twelve children with CP and fifteen TD children were used to create subject-specific musculoskeletal models and calculate HJCF using OpenSim. Root-mean-square-differences between left and right HJCF magnitude and orientation were computed and compared between participant groups (CP versus TD). Additionally, the influence on HJCF asymmetries solely due to the femoral morphology and solely due to the gait pattern was quantified. Our findings demonstrate that the gait pattern is the main contributor to asymmetric HJCFs in CP and TD children. Children with CP have higher HJCF asymmetries which is probably the result of larger asymmetries in their gait pattern compared to TD children. The gained insights from our study highlight that clinical interventions should focus on normalizing the gait pattern and therefore the hip joint loading to avoid the development of femoral deformities.

Changes in Parameters after High Tibial Osteotomy: Comparison of EOS System and Computed Tomographic Analysis

Unintended rotation of the distal tibia occurs during medial open-wedge high tibial osteotomy (MOWHTO). Computed tomography (CT) is the standard method of measuring lower limb alignment; however, the new low-dose EOS system allows three-dimensional limb modeling with automated measurements of lower limb alignment. This study investigated the differences between the changes in lower limb alignment profiles obtained using the EOS system and CT in patients who underwent MOWHTO. We investigated whether any factors contributed to the degree of deformation. Thirty patients were prospectively enrolled between October 2019 and February 2023. Changes in femoral and tibial torsion, femorotibial rotation, and posterior tibial slope were measured using pre- and post-MOWHTO CT and EOS images. We found no significant difference in pre- and postoperative tibial torsion or posterior tibial slope between CT and EOS. No variables showed a significant correlation with changes in the tibial torsion or posterior tibial slope. This study confirmed the possibility that the EOS system could replace CT in measuring changes in several parameters pre- and postoperatively. Furthermore, we confirmed that the distal tibia tended to be internally rotated after MOWHTO; however, we found no significantly related parameters related to deformation caused by MOWHTO.

3D Gait Analysis and Patient-reported Outcomes of Femoral Osteotomies for Torsional Deformity

BACKGROUND

Idiopathic torsional deformities causing pain and/or functional difficulty is an indication for a femoral derotational osteotomy (FDRO). Past studies have focused entirely on children with internal femoral torsional deformity (IFTD). This study aims to compare gait and outcomes between children with IFTD and those with external femoral torsional deformity (EFTD) after a FDRO.

METHODS

A retrospective review of all patients who underwent an FDRO between 1997 and 2020 at our institution. Data on typically developing (TD) children with no torsional deformity was used as a control group. We analyzed preoperative and postoperative standardized physical examination, 3-dimensional gait analysis, and Pediatric Outcomes Data Collection Instrument questionnaires.

RESULTS

There were 54 patients in total (IFTD=37, EFTD=17) and 20 patients in the control group. The EFTD cohort was older (IFTD=11.7, EFTD=14.7, P <0.05) and had a higher body mass index both preoperatively (IFTD=21.1 kg/m 2 , EFTD=32.1 kg/m 2 , P <0.05) and postoperatively (IFTD=20.2 kg/m 2 , EFTD=34.1 kg/m 2 , P <0.05). Preoperatively, 3-dimensional gait analysis elicited mean hip rotation in stance was more internal for IFTD cohort (10.8 degrees) and external for the EFTD cohort (-17.8 degrees) in comparison to the TD (2.4 degrees, P <0.001). Postoperatively, dynamic mean hip rotation during stance was -1.4 degrees for IFTD, whereas for EFTD, it was -5.4 degrees, which was different to the TD ( P <0.05). The IFTD group's Pediatric Outcomes Data Collection Instrument improved for transfer/basic mobility, sports/physical function, global functioning, and satisfaction with symptoms ( P <0.05). The EFTD group that only reported an improvement with the satisfaction with symptoms after surgery ( P <0.05).

CONCLUSIONS

Adolescents with surgically corrected IFTD show more improvement in gait and in patient-reported outcomes than those with surgically corrected EFTD. Children with EFTD persist in external rotation and have less satisfactory patient-reported outcomes after a FDRO in comparison those with IFTD.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Comparison of clinical with CT based evaluation for tibial torsion

PURPOSE

Tibial torsion is important to be factored in during calculations of angular deformities of the lower extremity. Three methods are commonly used, thigh foot angle, measurement of transmalleolar axis with proximal tibia or knee as a reference, and Computerized tomography. The purpose of the current study was to find out the effectiveness of clinical methods and compare CT based method for tibial torsion.

METHODS

A total of 68 limbs (34 subjects) were included. Tibial torsion was measured using thigh foot angle, transmalleolar axis in relation to knee forward position (Knee ankle axis) and CT based evaluation using Jend method.

RESULTS

Pearson correlation coefficient showed strong correlation between CT values and thigh foot angle (r = 0.848) as well as between CT values and Knee ankle axis (r = 0.889). Scatter plots also showed a linear distribution.

CONCLUSION

Both thigh foot angle and Knee ankle axis provide reliable alternative to ionizing CT in measuring tibial torsion.

Is there a persistent capital femoral epiphysis growth after screw fixation for slipped capital femoral epiphysis?

Femoral neck screwing during child development is controversial. The objective of this study was to evaluate the residual growth of the capital femoral physis after screw fixation. This retrospective study included children aged younger than 12 years treated for slipped capital femoral epiphysis (SCFE) with a single percutaneous partially threaded cannulated screw. The children were followed up for at least 1 year. Some patients also underwent prophylactic contralateral screwing. Preoperative, immediate postoperative and final follow-up X-rays were evaluated to determine the degree of slippage, pin–joint ratio (PJR), neck–pin ratio (NPR), number of threads crossing the physis, neck–shaft angle (NSA), screw–physis angle and screw position in the physis. We included 17 patients (29 hips: 18 SCFE and 11 prophylactic) with a mean age of 10.1 years (range: 7.1–11.9 years) at the time of surgery. Significant evolution of radiological growth parameters of the proximal femoral physis was noted during a mean follow-up of 2.4 years (range: 1–4.3 years). The mean PJR significantly decreased from 7.3 to 6.0, the mean NPR significantly decreased from 106 to 96 and the mean number of threads beyond the physis decreased from 3.3 to 1.8. The mean NSA decreased by 6.5°, from 139° to 132.5°. Persistent capital femoral epiphysis growth occurs after screw fixation. The NSA significantly decreases over time but remains within the physiological limits.

Level of evidence: IV (case series)

Coronal and Transverse Malalignment in Pediatric Patellofemoral Instability

Patellofemoral instability (PFI) encompasses symptomatic patellar instability, patella subluxations, and frank dislocations. Previous studies have estimated the incidence of acute patellar dislocation at 43 per 100,000 children younger than age 16 years. The medial patellofemoral ligament (MPFL) complex is a static soft tissue constraint that stabilizes the patellofemoral joint serving as a checkrein to prevent lateral displacement. The causes of PFI are multifactorial and not attributed solely to anatomic features within the knee joint proper. Specific anatomic features to consider include patella alta, increased tibial tubercle–trochlear groove distance, genu valgum, external tibial torsion, femoral anteversion, and ligamentous laxity. The purpose of this paper is to provide a review of the evaluation of PFI in the pediatric and adolescent patient with a specific focus on the contributions of coronal and transverse plane deformities. Moreover, a framework will be provided for the incorporation of bony procedures to address these issues.

A Validated, Automated, 3-Dimensional Method to Reliably Measure Tibial Torsion

BACKGROUND

Tibial torsion is a twist in the tibia measured as an angle between a proximal axis line and a distal axis line. Abnormal torsion has been associated with a variety of painful clinical syndromes of the lower limb. Measurements of normal tibial torsion reported by different authors vary by 100% (ranging from 20° to 42°), making it impossible to determine normal and pathological levels.

PURPOSE

To address the problem of unreliable measurements, this study was conducted to define an automated, validated computer method to calculate tibial torsion. Reliability was compared with current clinical methods. The difference between measurements of torsion generated from computed tomography (CT) and magnetic resonance imaging (MRI) scans of the same bone, and between males and females, was assessed.

STUDY DESIGN

Controlled laboratory study.

METHODS

Previous methods of analyzing tibial torsion were reviewed, and limitations were identified. An automated measurement method to address these limitations was defined. A total of 56 cadaveric and patient tibiae (mean ± SD age, 37 ± 15 years; range, 17-71 years; 28 female) underwent CT scanning, and 3 blinded assessors made torsion measurements by applying 2 current clinical methods and the automated method defined in the present article. Intraclass correlation coefficient (ICC) values were calculated. Further, 12 cadaveric tibiae were scanned by MRI, stripped of tissue, and measured using a structured light (SL) scanner. Differences between torsion values obtained from CT, SL, and MRI scans, and between males and females, were compared using t tests. SPSS was used for all statistical analysis.

RESULTS

When the automated method was used, the tibiae had a mean external torsion of 29°± 11° (range, 9°-65). Automated torsion assessment had excellent reliability (ICC, 1), whereas current methods had good reliability (ICC, 0.78-0.81). No significant difference was found between the torsion values calculated from SL and CT (P = .802), SL and MRI (P = .708), or MRI and CT scans (P = .826).

CONCLUSION

The use of software to automatically perform measurements ensures consistency, time efficiency, validity, and accuracy not possible with manual measurements, which are dependent on assessor experience.

CLINICAL RELEVANCE

We recommend that this method be adopted in clinical practice to establish databases of normal and pathological tibial torsion reference values and ultimately guide management of related conditions.

Differences between the Craig's test and computed tomography in measuring femoral anteversion in patients with anterior cruciate ligament injuries

[Purpose] This study aimed to compare the Craig’s test and computed tomography (CT) in measuring the femoral anteversion angle (FAA) in patients with anterior cruciate ligament (ACL) injuries. The relationship between the FAA measured on CT, and the range of axial rotation of the hip joint and muscle tightness around the hip joint was also investigated. [Participants and Methods] Twenty-six patients who received CT examination within 3 months after ACL reconstruction were enrolled in this study. The Craig’s test, internal and external rotation of the hip, the Ely test, Ober’s test, and FAA on the CT were assessed. [Results] The FAA on the Craig’s test and CT in female patients was 24.3 ± 3.9° and 23.0 ± 10.3°, respectively on the uninjured side and 25.0 ± 5.2° and 20.3 ± 11.2°, respectively on the injured side, indicating no significant correlation between the 2 measurement techniques. In contrast, the FAA on the CT was significantly correlated with the range of internal rotation of the hip, which was 40.5 ± 6.1° on the uninjured side and 37.8 ± 5.6° on the injured side. [Conclusion] The results suggest that measuring the internal hip rotation range rather than the Craig’s test, provides more reliable estimates of the magnitude of FAA, and may help to evaluate the risk of ACL injuries in female athletes.

[Treatment of rotational malalignment of the lower leg]

BACKGROUND

Rotational malalignment after intramedullary nailing of tibial shaft fractures is not uncommon. In-toeing and out-toeing conditions in children are often the reason for orthopedic and traumatological medical consultation.

OBJECTIVE

Evaluation of diagnostic modalities and therapeutic options for rotational malalignment in relationship to the patient's age. Surgical indications and efficacy of specific surgical techniques.

MATERIAL AND METHODS

Systematic literature search in the German Institute for Medical Documentation and Information (DIMDI) and MEDLINE and evaluation of the currently published articles.

RESULTS

In adults computed tomography (CT) scanning is the gold standard for measuring the rotational alignment of the lower leg. To avoid exposure to ionizing radiation, magnetic resonance imaging (MRI) is currently the preferred modality in children and adolescents. The indications for corrective osteotomy are dependent on the functional complaints as well as the rotation angle measured by CT or MRI. Presently, there is no published study which demonstrates a correlation between rotation of the lower leg and the development of arthrosis in the knee or ankle joint. When a rotational osteotomy above the tibial tubercle is performed, correction of the rotation and the distance between the tibial tuberosity and the trochlear groove (TT-TG) and therefore patellofemoral imbalance can be effectively treated. Treatment of rotational malalignment after tibial shaft fractures is performed by diaphyseal osteotomy with intramedullary nail stabilization. In children, supramalleolar rotational osteotomy with subsequent locking plate osteosynthesis or stabilization using external fixation is performed for torsion correction.

CONCLUSION

If there is a suspicion of rotational malalignment in the lower leg, a CT scan can be performed in adults and MRI in children and adolescents. Surgical indications for corrective osteotomy are dependent on functional complaints as well as the CT and MRI measurements. The CT and MRI reference values are only published according to the method of Waidelich et al. and Jend et al.

Alignment in the transverse plane, but not sagittal or coronal plane, affects the risk of recurrent patella dislocation

PURPOSE

Abnormalities of lower extremity alignment (LEA) in recurrent patella dislocation (RPD) have been studied mostly by two-dimensional (2D) procedures leaving three-dimensional (3D) factors unknown. This study aimed to three-dimensionally examine risk factors for RPD in lower extremity alignment under the weight-bearing conditions.

METHODS

The alignment of 21 limbs in 15 RPD subjects was compared to the alignment of 24 limbs of 12 healthy young control subjects by an our previously reported 2D-3D image-matching technique. The sagittal, coronal, and transverse alignment in full extension as well as the torsional position of the femur (anteversion) and tibia (tibial torsion) under weight-bearing standing conditions were assessed by our previously reported 3D technique. The correlations between lower extremity alignment and RPD were assessed using multiple logistic regression analysis. The difference of lower extremity alignment in RPD between under the weight-bearing conditions and under the non-weight-bearing conditions was assessed.

RESULTS

In the sagittal and coronal planes, there was no relationship (statistically or by clinically important difference) between lower extremity alignment angle and RPD. However, in the transverse plane, increased external tibial rotation [odds ratio (OR) 1.819; 95% confidence interval (CI) 1.282-2.581], increased femoral anteversion (OR 1.183; 95% CI 1.029-1.360), and increased external tibial torsion (OR 0.880; 95% CI 0.782-0.991) were all correlated with RPD. The tibia was more rotated relative to femur at the knee joint in the RPD group under the weight-bearing conditions compared to under the non-weight-bearing conditions (p < 0.05).

CONCLUSIONS

This study showed that during weight-bearing, alignment parameters in the transverse plane related to the risk of RPD, while in the sagittal and coronal plane alignment parameters did not correlate with RPD. The clinical importance of this study is that the 3D measurements more directly, precisely, and sensitively detect rotational parameters associated with RPD and hence predict risk of RPD.

LEVEL OF EVIDENCE

III.

A comparison of three methods of measuring tibial torsion in children with myelomeningocele and normally developing children

Abnormal tibial torsion is a common pediatric problem, and there are many existing measurement methods. The purpose of this study was to compare three methods of measuring tibial torsion for its evaluation: computed tomography, physical examination, and motion capture. Twenty healthy children and 20 children with myelomeningocele underwent measures of tibial torsion bilaterally. Measurements were compared using correlation and Bland-Altman plots of the difference between measurements. All three measurements were moderately correlated in controls (r ≥ 0.49, P ≤ 0.002) and in patients (r ≥ 0.51, P ≤ 0.001). In controls, the motion capture measurements were on average 2° more lateral than the clinical measurements whereas motion capture and clinical measurements were 13° and 15° more medial than CT measurements, respectively. Similarly for patients, motion capture measurements were on average 5° more medial than clinical measurements, and motion capture and clinical measurements were 26° and 22° more medial than CT measurements. The approximate 20° difference between the clinical or motion capture measures and the CT measure suggests that clinical evaluation identifies different axes than those defined based on skeletal anatomy. Clinical or motion capture methods may be used in lieu of imaging methods for measuring tibial torsion with the knowledge that these methods provide less lateral measurements than measurements obtained using CT. Clin. Anat. :1043-1048, 2017. © 2017 Wiley Periodicals, Inc.

Risk of vascular injury when screw drilling for tibial tuberosity transfer

PURPOSE

During tibial tubercle transfer, popliteal vessels are at risk from drills and screws. The risk is around 0.11%, as described in the literature. We reviewed knee injected CT scan for analysis of the location of arteries, identified landmarks allowing minimizing risks, and defined a safe zone.

MATERIAL AND METHOD

Distances between the posterior cortex and arteries were measured on CT scans from 30 adults (60 knees) at three levels (proximal part of the tibial tuberosity, 20 mm and 40 mm distally). Data were used to create a "risk map" with different angular sectors where the frequency of the presence of arteries was analyzed in each area. We also analyzed the position of 68 screws of 47 patients who underwent a medial tibial tuberosity transfer.

RESULTS

The nearest distance between artery and the posterior tibial cortex was found at the level corresponding to the top of the tuberosity with less than 1 mm, while the largest distance was found at the distal level. We were able to define a safe zone for drilling through the posterior tibial cortex which allows a safe fixation for the screws. This zone corresponds to the medial third of the posterior cortex. When the safe zone is not respected, screws that overtake the posterior cortex may be close to arteries as observed for 37 of the 68 screws analyzed.

CONCLUSION

We described new landmarks and recommendations to avoid this complication during tibial tuberosity transfer.

Accuracy and Reliability of Computed Tomography and Magnetic Resonance Imaging Compared With True Anatomic Femoral Version

BACKGROUND

Abnormal torsion of the femur is correlated to lower extremity pathologies. Although computed tomography (CT) scan is the gold standard torsional measurement, magnetic resonance imaging (MRI) is proposed as a viable alternative. Our aim was to determine the accuracy and consistency of MRI and CT femur rotational studies based on 4 described protocols.

METHODS

Twelve cadaveric femora were stripped of soft tissue before imaging and physical assessment of torsion. Four advanced imaging series were obtained for each specimen: CT with axial cuts of the femoral neck (CT-axial); CT with oblique cuts of the femoral neck (CT-oblique); MRI with axial cuts of the femoral neck (MR-axial); MRI with oblique cuts of the femoral neck (MR-oblique). Anatomic specimens were placed with the posterior femoral condyles flat on a dissection table for assessment of true torsion with digital images. Three independent reviewers performed all measurements, including true torsion, using imaging software. Bland-Altman analysis was repeated with the data from each reviewer.

RESULTS

Interobserver repeatability for all groups was high at 0.95, 0.87, 0.90, 0.97, and 0.92 for CT-axial, CT-oblique, MR-axial, MR-oblique, and true torsion, respectively. CT-axial had the lowest mean difference from clinical imaging for all three observers (all <1 degree) and held the tightest 95% limits of agreement for 2/3 observers. As torsion increases from neutral, MR-oblique linearly overestimates the rotation compared with true torsion. CT-oblique and MR-axial showed slightly greater differences from true torsion compared with CT-axial, but did not reach clinical significance.

CONCLUSIONS

CT-axial was both most accurate and reproducible when compared with true torsion of the femur and should be the gold standard imaging modality; however, both MR-axial and CT-oblique were accurate to a level that is likely less than clinical significance. MR-axial images should be used in clinical situations where radiation exposure needs to be limited. MR-oblique images can overestimate true antetorsion and should not be used.

CLINIC SIGNIFICANCE

CT-axial followed by MRI-axial is the most accurate and consistent in measuring true torsion of the femur.

Intra- and inter-examiner reliability of goniometer and inclinometer use in Craig's test

[Purpose] The purpose of this study was to determine the inter- and intra-examiner reliability of measurement methods for femoral anterversion during Craig’s test. [Subjects and Methods] The study included 37 healthy participants (20 males and 17 females). Two novice examiners (Department of Physical Therapy students at Silla University) used three different methods to measure the femoral anterversion during Craig’s test: a goniometer, a goniometer with a laser beam, and an inclinometer. [Results] The intra-examiner reliability was high for both examiners with all three measurement methods, with scores of 0.82, 0.86, and 0.73 for examiner 1 and 0.74, 0.78, and 0.72 for examiner 2 for the goniometer, goniometer with the laser beam, and inclinometer, respectively. The inter-examiner reliability during Craig’s test was below moderate for both the goniometer (0.25) and inclinometer (0.27) and moderate for the goniometer with the laser beam (0.62). [Conclusion] This study found that Craig’s test using a goniometer with a laser beam had high intra-examiner reliability and moderate inter-examiner reliability. Clinically, these findings may supplement existing measurement skills and reduce the difficulty of locating the goniometer axis during Craig’s test.

Development of a method for measuring femoral torsion using real-time ultrasound

Excessive femoral torsion has been associated with various musculoskeletal and neurological problems. To explore this relationship, it is essential to be able to measure femoral torsion in the clinic accurately. Computerized tomography (CT) and magnetic resonance imaging (MRI) are thought to provide the most accurate measurements but CT involves significant radiation exposure and MRI is expensive. The aim of this study was to design a method for measuring femoral torsion in the clinic, and to determine the reliability of this method. Details of design process, including construction of a jig, the protocol developed and the reliability of the method are presented. The protocol developed used ultrasound to image a ridge on the greater trochanter, and a customized jig placed on the femoral condyles as reference points. An inclinometer attached to the customized jig allowed quantification of the degree of femoral torsion. Measurements taken with this protocol had excellent intra- and inter-rater reliability (ICC2,1 = 0.98 and 0.97, respectively). This method of measuring femoral torsion also permitted measurement of femoral torsion with a high degree of accuracy. This method is applicable to the research setting and, with minor adjustments, will be applicable to the clinical setting.

Measuring femoral and rotational alignment: EOS system versus computed tomography

INTRODUCTION

Computed tomography (CT) is currently the reference standard for measuring femoral and tibial rotational alignment. The EOS System is a new biplanar low-dose radiographic device that allows 3-dimensional lower-limb modelling with automated measurements of femoral and tibial rotational alignment (torsion).

HYPOTHESIS

Femoral and tibial torsion measurements provided by the EOS System are equivalent to those obtained using CT.

MATERIALS AND METHODS

In a retrospective analysis of 43 lower limbs in 30 patients, three senior radiologists measured femoral and tibial torsion on both CT and EOS images. Agreement between CT and EOS values was assessed by computing Pearson's correlation coefficient and interobserver reproducibility by computing the intraclass correlation coefficient (ICC).

RESULTS

Femoral torsion was 13.4° by EOS vs. 13.7° by CT (P=0.5) and tibial torsion was 30.8° by EOS vs. 30.3° by CT (P=0.4). Strong associations were found between EOS and CT values for both femoral torsion (P=0.93) and tibial torsion (P=0.89). With EOS, the ICC was 0.93 for femoral torsion and 0.86 for tibial torsion; corresponding values with CT were 0.90 and 0.92.

DISCUSSION

The EOS system is a valid alternative to CT for lower-limb torsion measurement. EOS imaging allows a comprehensive evaluation in all three planes while substantially decreasing patient radiation exposure.

LEVEL OF EVIDENCE

Level III, case-control.

Total knee arthroplasty in patients with excessive external tibial torsion >45° and patella instability--surgical technique and follow up

Patients presenting with advanced knee osteoarthritis (OA), excessive external tibial torsion (EETT) and chronic patella subluxation pose significant surgical challenges. A combination of TKA, tibial derotation osteotomy, and tibial tuberosity transfer was performed in ten patients (twelve knees) with OA secondary to EETT and patellar instability. Six weeks of non weight-bearing and flexion limited to 45° was mandated after surgery. The mean follow-up and patient age was 81months (range, 14 to 159) and 56years (range, 49 to 62). The mean pre-operative external tibial torsion was 62°, with an average rotational correction of 30°. Significant improvement was found in the Knee Society Score, SF-12 and all WOMAC questionnaire score subscales (p<0.0001); 5 patients had complications, but no loosening or nonunion was seen.

Magnetic resonance imaging analysis of rotational alignment in patients with patellar dislocations

BACKGROUND

The role of anatomic risk factors in patellofemoral instability is not yet fully understood, as they have been observed in patients either alone or in combination and in different degrees of severity.

PURPOSE

To prospectively analyze rotational limb alignment in patients with patellofemoral instability and in controls using magnetic resonance imaging (MRI).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Thirty patients (mean age, 22.9 y; range, 12-41 y) with a history of patellar dislocation and 30 age- and sex-matched controls (mean age, 25.2 y; range, 16-37 y) were investigated. The patients underwent MRI of the leg at 1.5 T using a peripheral angiography coil and a T2-weighted half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence for measuring femoral antetorsion, tibial torsion, knee rotation, and mechanical axis deviation (MAD). The mean values of these parameters were compared between patients and controls. In addition, the patients underwent an assessment to determine the influence of rotational limb alignment on lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, Insall-Salvati index, and tibial tuberosity-trochlear groove distance.

RESULTS

Patients had 1.56-fold higher mean femoral antetorsion (20.3° ± 10.4° vs 13.0° ± 8.4°; P < .01) and 1.6-fold higher knee rotation (9.4° ± 5.0° vs 5.7° ± 4.3°; P < .01) compared with controls. Moreover, patients had 2.9 times higher MAD (0.81 ± 0.75 mm vs -0.28 ± 0.87 mm; P < .01). Differences in tibial torsion were not significant. Also, there were no significant correlations between parameters of rotational alignment and standard anatomic risk factors.

CONCLUSION

Our results suggest that some patients with nontraumatic patellar instability have greater internal femoral rotation, greater knee rotation, and a tendency for genu valgum compared with healthy controls. Rotational malalignment may be a primary risk factor in patellar dislocation that has so far been underestimated.

Patellofemoral disorders: role of computed tomography and magnetic resonance imaging in defining abnormal rotational lower limb alignment

Background:

The contribution of lower limb rotational malalignment to patellofemoral pain and instability has been well recognized. The purpose of the present study is to review the role of computed tomography (CT) and magnetic resonance imaging (MRI) in assessment of abnormal rotational alignment of lower limb.

Evidence Acquisition:

An analysis of all available literature in the English language through 2010 was performed to provide data on a comparison between MRI and CT—specifically, the techniques and normative values used to determine abnormal lower limb alignment.

Results:

CT and MRI are highly accurate in defining abnormal alignment of the lower limb. Determination of axis of femoral anteversion in proximal femur has been the subject of debate in the literature. The determination of distal femoral condylar axis, proximal tibial axis and distal tibial axis are less controversial.

Conclusions:

CT and MRI are both used for assessing the rotational abnormalities of the femur and tibia during evaluation for patellofemoral disorders. MRI has an advantage over CT because femoral anteversion measurements are more accurate and ionizing radiation is avoided. A standardized protocol defining the level and axes for measurement of femoral and tibial alignment indices should be used to maintain consistency in measurements.

A three-dimensional axis for the study of femoral neck orientation

A common problem in the quantification of the orientation of the femoral neck is the difficulty to determine its true axis; however, this axis is typically estimated visually only. Moreover, the orientation of the femoral neck is commonly analysed using angles that are dependent on anatomical planes of reference and only quantify the orientation in two dimensions. The purpose of this study is to establish a method to determine the three-dimensional orientation of the femoral neck using a three-dimensional model. An accurate determination of the femoral neck axis requires a reconsideration of the complex architecture of the proximal femur. The morphology of the femoral neck results from both the medial and arcuate trabecular systems, and the asymmetry of the cortical bone. Given these considerations, two alternative models, in addition to the cylindrical one frequently assumed, were tested. The surface geometry of the femoral neck was subsequently used to fit one cylinder, two cylinders and successive cross-sectional ellipses. The model based on successive ellipses provided a significantly smaller average deviation than the two other models (P < 0.001) and reduced the observer-induced measurement error. Comparisons with traditional measurements and analyses on a sample of 91 femora were also performed to assess the validity of the model based on successive ellipses. This study provides a semi-automatic and accurate method for the determination of the functional three-dimensional femoral neck orientation avoiding the use of a reference plane. This innovative method has important implications for future studies that aim to document and understand the change in the orientation of the femoral neck associated with the acquisition of a bipedal gait in humans. Moreover, the precise determination of the three-dimensional orientation has implications in current research involved in developing clinical applications in diagnosis, hip surgery and rehabilitation.

Femoral anteversion in the hip: comparison of measurement by computed tomography, magnetic resonance imaging, and physical examination

PURPOSE

The purpose of this study was to evaluate the correlation between computed tomography (CT) and magnetic resonance imaging (MRI) measurements of femoral anteversion, as well as the relation of anteversion with physical examination and radiographic findings.

METHODS

Preoperative CT and MRI measurements of anteversion along with clinical examination were performed on 129 consecutive hips before hip arthroscopy for nonarthritic hip injuries. All anteversion measurements were performed by 2 musculoskeletal radiologists. The radiographic findings and physical examination findings were analyzed for statistically significant correlations. For statistical analysis purposes, the patients were divided into 3 groups according to the mean CT anteversion measurement: group I (low), less than 10°; group II (medium), 10° to 22°; and group III (high), greater than 22°.

RESULTS

High interobserver correlation was found for femoral anteversion measurement by CT and MRI (r = 0.95 and r = 0.86, respectively; P < .0001 for both). CT and MRI measurements showed high correlation with each other (r = 0.80, P < .0001). However, in 96% of the cases, the CT measurement was larger, with a mean difference of 8.9° (range, -37° to 1.5°). A significant correlation coefficient was found between internal rotation and anteversion angles as measured by CT (r = 0.36, P < .0001). However, no correlation was found with other hip movement measurements. Abnormal femoral acetabular bony architecture of the hip was found in 64% of the patients; isolated cam impingement was more prevalent in group I, whereas isolated pincer impingement was more prevalent in group III (P = .01).

CONCLUSIONS

Although high correlation was found between anteversion angle measurements by CT and MRI, significant discrepancies in the absolute anteversion number between the 2 techniques suggest that they may not be interchangeable. Furthermore, CT was found to have higher interobserver reliability than MRI. There was a significant correlation between CT and examination of internal rotation of the hip. Clinically, the findings of the study show that the diagnosis of excessive femoral anteversion or retroversion should have different thresholds according to MRI and CT measurements; moreover, the diagnosis should not rely exclusively on either examination or radiologic criteria.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Tibial torsion in cerebral palsy: validity and reliability of measurement

Physical examinations of tibial torsion are used for preoperative planning and to assess outcomes of tibial osteomy in patients with cerebral palsy (CP). The thigh-foot angle (TFA) and transmalleolar axis (TMA) are commonly used, and the second toe test recently was introduced. However, the validity and reliability of the three methods have not been clarified. This study was performed to evaluate the validity and reliability of these physical measures. We recruited 18 patients (36 limbs) with CP. During reliability sessions, three raters with various levels of orthopaedic experience independently measured tibial torsion using the three different methods during one day before surgery. Validity was assessed by performing a correlation study between physical examination and two-dimensional computed tomographic (CT) findings. Interobserver reliability was greatest for the TMA followed by TFA and then by the second toe test with intraclass correlation coefficients of 0.92, 0.74, and 0.57, respectively. In terms of the concurrent validity, the correlation coefficients (r) for the CT measurements were 0.62, 0.52, and 0.55. When depicting tibial torsion by physical examination, all three methods had substantial validity, but test reliability and validity were highest for TMA measurements.

LEVEL OF EVIDENCE

Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The association between idiopathic clubfoot and increased internal hip rotation

Clinical observation suggests the coexistence of increased internal hip rotation in limbs with clubfoot, thereby providing an additional, and perhaps overlooked, site of deformity to account for an intoeing gait in these limbs. Furthermore, assuming a genetic basis exists for exaggerated femoral and/or acetabular anteversion, which are the possible cause(s) for increased internal hip rotation, this association could provide another key to the multifactorial etiology of clubfoot. We asked whether such an association exists and retrospectively reviewed 114 children (178 clubfeet). We then tested for an association between clubfoot and increased internal hip rotation. These rotational measurements were compared with published normative data on torsion in children. In cases of unilateral clubfoot, an additional analysis compared the rotational profiles of the affected and unaffected extremities. Increased internal hip rotation occurred more frequently in limbs with idiopathic clubfoot. In patients with unilateral clubfoot, the affected extremities manifested greater internal hip rotation than the unaffected extremities, whereas the latter showed no difference in internal hip rotation compared with normative values. Clinical evaluation of intoeing in children with a history of clubfoot should include a rotational profile to determine the level(s) of deformity and guide therapeutic intervention.

LEVEL OF EVIDENCE

Level III, prognostic study (case control study). See Guidelines for Authors for a complete description of levels of evidence.

Correlation between lower limb bone morphology and gait characteristics in children with spastic diplegic cerebral palsy

BACKGROUND

Children with spastic diplegic cerebral palsy (CP) exhibit abnormal walking patterns and frequently develop lower limb, long bone deformities. It is important to determine if any relationship exists between bone morphology and movement of the lower limbs in children with CP. This is necessary to explain and possibly prevent the development of these deformities.

METHODS

This study investigated the relationship between bone morphology and gait characteristics in 10 healthy children (age range, 6-13 years; mean, 8 years 7 months; SD, +/-2 years 7 months) and 9 children with spastic diplegic CP (age range, 6-12 years; mean, 9 years 2.5 months; SD, +/-1 year 10.5 months) with no previous surgery. Three-dimensional magnetic resonance images were analyzed to define bone morphology. Morphological characteristics, such as the bicondylar angle, neck-shaft angle, anteversion angle, and tibial torsion, were measured. Gait analyses were performed to obtain kinematic characteristics of CP and normal children's gait. Principal component analysis was used to reduce the dimensionality of 27 parameters (26 kinematics variables and age of the children) to 8 independent variables. Correlations between gait and bone morphology were determined for both groups of children.

RESULTS

Results indicated that in healthy children, hip adduction was correlated with neck-shaft and bicondylar angles. In CP children, pelvic obliquity correlated with neck-shaft angle, and foot rotation with bicondylar angle. In the transverse plane, hip and pelvic rotational kinematics were related to femoral anteversion in healthy children and to tibial torsion in CP children.

CONCLUSION

Different development was observed in femoral and tibial morphology between CP and healthy children. The relationship between bone shape and dynamic gait patterns also varied between these populations. This needs to be taken into account, particularly when surgical treatment is planned.

CLINICAL RELEVANCE

Understanding the relationship between gait abnormality and bone deformity could eventually help in developing treatment regimens that will address gait deviations at the correct level and promote normal bone growth in children with CP.

Proximal femoral geometry in cerebral palsy

There is much debate about the nature and extent of deformities in the proximal femur in children with cerebral palsy. Most authorities accept that increased femoral anteversion is common, but its incidence, severity and clinical significance are less clear. Coxa valga is more controversial and many authorities state that it is a radiological artefact rather than a true deformity.

We measured femoral anteversion clinically and the neck-shaft angle radiologically in 292 children with cerebral palsy. This represented 78% of a large, population-based cohort of children with cerebral palsy which included all motor types, topographical distributions and functional levels as determined by the gross motor function classification system.

The mean femoral neck anteversion was 36.5° (11° to 67.5°) and the mean neck-shaft angle 147.5° (130° to 178°). These were both increased compared with values in normally developing children. The mean femoral neck anteversion was 30.4° (11° to 50°) at gross motor function classification system level I, 35.5° (8° to 65°) at level II and then plateaued at approximately 40.0° (25° to 67.5°) at levels III, IV and V. The mean neck-shaft angle increased in a step-wise manner from 135.9° (130° to 145°) at gross motor function classification system level I to 163.0° (151° to 178°) at level V. The migration percentage increased in a similar pattern and was closely related to femoral deformity.

Based on these findings we believe that displacement of the hip in patients with cerebral palsy can be explained mainly by the abnormal shape of the proximal femur, as a result of delayed walking, limited walking or inability to walk. This has clinical implications for the management of hip displacement in children with cerebral palsy.

Tibial torsion in non-arthritic Indian adults: a computer tomography study of 100 limbs

BACKGROUND

Knowledge of normal tibial torsion is mandatory during total knee replacement (TKR), deformity correction and fracture management of tibia. Different values of tibial torsion have been found in different races due to biological and mechanical factors. Value of normal tibial torsion in Indian limbs is not known, hence this study to determine the norm of tibial torsional value in normal Indian population.

MATERIALS AND METHODS

Computer tomography (CT) scans were performed in 100 non-arthritic limbs of 50 Indian adults (42 males, eight females; age 26-40 years). Value of tibial torsion was measured using dorsal tangent to tibial condyles proximally and bimalleolar axis distally.

RESULTS

Normal tibial torsion was found to be 21.6 +/- 7.6 (range 4.8 to 39.5) with none of the values in internal rotation. Right tibia was externally rotated by 2 degrees as compared to the left side (P 0.029). No significant difference was found in male and female subjects. Value of tibial torsion was less than in Caucasian limbs, but was comparable to Japanese limbs when studies using similar measurement technique were compared.

CONCLUSIONS

Indian limbs have less tibial torsion than Caucasian limbs but the value of tibial torsion is comparable to Japanese limbs.

Radiographic and computed tomographic determination of femoral varus and torsion in the dog

Diagnosis and quantification of femoral varus and femoral torsion using radiographs is technically challenging due to the difficulty in determining proper positioning. The purpose of this study is to describe a computed tomographic technique for determination of femoral varus and femoral torsion and to compare this technique, and standard radiography, to anatomic preparation, for the measurement of femoral varus and femoral torsion in normal dogs. Nine canine cadavers, visually and radiographically free of orthopedic disease of the hip and stifle joints, were utilized for analysis. Femoral varus was determined using a craniocaudal radiograph, a craniocaudal radiograph obtained after confirming accurate positioning using horizontal beam fluoroscopy, and computed tomography (CT). Femoral torsion (expressed as angle of version) was determined using an axial radiographic projection obtained from distal to proximal and CT. Each femur was dissected free of soft tissues, and direct determination of femoral varus and femoral torsion was performed using digital photographic images. All radiologic and photographic images were digitally measured to quantify the magnitude of femoral varus and femoral torsion. For femoral varus, no difference (P = 0.149) between the three different imaging techniques and the anatomic preparation was identified. For femoral torsion, no difference (P = 0.059) between the two imaging techniques and the anatomic preparation was identified. Well positioned radiographs and the described computed tomographic method are both as accurate as anatomic preparation for the measurement of both femoral varus and femoral torsion in normal dogs.

Dance training intensity at 11-14 years is associated with femoral torsion in classical ballet dancers

OBJECTIVE

To examine in a cross sectional study the influence of femoral torsion (FT) and passive hip external rotation (PER) on turnout (TO). Starting age, years of classical ballet training, and current and past dance training intensity were assessed to determine their influence on FT, PER, and TO in pre-professional female dancers.

METHODS

Sixty four dancers (mean (SD) age 18.16 (1.80) years) were recruited from four different dance training programmes. They completed a dance history questionnaire. FT was measured using a clinical method. PER was measured with the subjects prone, and TO was measured with the subjects standing.

RESULTS

Mean TO was 136 degrees, mean unilateral PER was 49.4 degrees, and mean FT was 18.4 degrees. A positive correlation was observed between PER combined (PERC) and TO (r = 0.443, p < 0.001). A negative association was found between FT combined (FTC) and PERC (r = -0.402, p = 0.001). No association was found between starting age or years of classical ballet training and FTC, PERC, or TO. Dancers who trained for six hours a week or more during the 11-14 year age range had less FT than those who trained less (mean difference 6 degrees, 95% confidence interval 1.4 to 10.3). Students currently training for longer had higher levels of TO (p < 0.001) but comparable PERC and FTC.

CONCLUSION

FT is significantly associated with PERC. Dancers who trained for six hours a week or more at 11-14 years of age had significantly less FT. FTC had a significant influence on PERC, but no influence on the execution of TO.

Ethnic-, gender-, and age-related differences in femorotibial angle, femoral antetorsion, and tibiofibular torsion: cross-sectional study among healthy Japanese and Australian Caucasians

The current study was conducted to examine ethnic, gender, and age-related differences in femorotibial angle (FTA), femoral antetorsion and tibiofibular torsion. Healthy Japanese (n = 120) and Australian Caucasian (n = 82) subjects were examined using a series of clinically reliable methods for measuring FTA and torsion of the lower limb. Subjects between 18-29 years of age were categorized as younger, 30-59 years as middle age, and 60 or more as older age. Three-way analysis of variance was utilized for data analysis. The Japanese subjects had significantly greater FTA (more varus) than the Australian subjects (P < 0.001). Femoral antetorsion in the Japanese subjects was significantly smaller in middle and older age groups than younger group (P < 0.05), but did not differ between the age groups in the Australian subjects. Further, tibiofibular torsion in female subjects was significantly greater in younger and middle age groups than the older age group (P < 0.01), but was not different between different age groups in males. The results suggest that healthy Japanese may have more genu varus alignment compared to the corresponding Australian population. Age-related ethnic and gender differences in femoral and tibiofibular torsion are worthy of further study.