Determination of the amount of leg length inequality that alters spinal posture in healthy subjects using rasterstereography

Scoliosis and Lower Limb Inequality: To Lift or Not to Lift, That Is the Question

In subjects with scoliotic alterations of the spine, asymmetrical lengths of the lower limbs are frequently observed, a condition commonly referred to as leg length inequality (LLI) or discrepancy (LLD). This asymmetry can induce pelvic misalignments, manifested by an asymmetric height of the iliac crests, and consequently an alteration of the spine's axis. Although correcting this discrepancy might appear to be a straightforward solution, further investigation may reveal other indications. The purpose of this article is to aid clinicians confronted with the decision of whether to compensate for an LLI in individuals with scoliosis, encompassing both adolescents and adults. It presents a literature review on the incidence of LLIs in the general population, distinguishing between structural LLI (sLLI) and functional LLI (fLLI) types of LLIs, and quantifying their magnitude with clinical and instrumental evaluation. Additionally, it links these two types of LLIs to the type of scoliosis (structural or functional). From a clinical perspective, it also examines the compensatory mechanisms employed by the pelvis in the presence of structural or functional LLIs in order to draw useful indications for therapeutic decisions. Moreover, it proposes an additional evaluation parameter in the coronal plane, namely the central sacral vertical line (CSVL), to aid in the decision-making process regarding LLI compensation. Although this parameter has been documented in the literature, it has been little associated with LLIs. The findings indicate that scoliotic discrepancies should be compensated (conservatively or surgically) only when the imbalance of the femoral heads is on the same side as the imbalance of the sacrum and the iliac crests; this corrective action should result in a reduction of the overhang in the coronal plane.

The Effect of Breast Size on Spinal Posture

Macromastia can cause various clinical symptoms, such as low back and shoulder pain as well as sacro-iliac disorders. Because of these symptoms, some women consider breast reduction surgery. So far there does not exist a clear correlation between breast size and back pain. Purpose of this study was to evaluate if increasing breast size has a measurable effect on women's posture using radiation free surface topography.A total of 100 women were grouped according to their breast cup size into four groups (Cup Size: A, B, C, D). All female subjects were measured with a surface topography system, and their spinal posture and pelvic position were analysed accordingly.Our results showed that cup size affects kyphotic angle (p = 0.027) and surface rotation (p = 0.039) significantly. Kyphotic angle increased with cup size. Multiple linear regression analysis, however, revealed that the body mass index has the greatest influence on woman's posture, showing significant correlation to kyphotic and lordotic angle (p < 0.01), as to trunk (p < 0.01) and pelvic inclination (p = 0.02).This is the first study that evaluates the influence of increasing breast size on posture using surface topography. The results match with previous studies using different measuring techniques. However, the great influence of BMI on posture is also confirmed. Therefore, in clinical practice these factors should be taken into account and be approached. Surface topography seems to be a promising tool to further investigate the influence of breast size on posture.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Effectiveness of Early Rehabilitation in Limiting the Progression of Idiopathic Scoliosis

Background: The purpose of this study was to assess specific rehabilitation methods' effectiveness in early idiopathic scoliosis (IS) development, focusing on lower limb functional inequality's role in scoliosis progression. Materials and Methods: This study comprised 812 patients aged 6-16 years at risk of developing idiopathic scoliosis (IS). The mean (SD) age was 10.66 (3.16) years. Patients were categorized into high- and medium-risk groups based on the angle of trunk rotation (ATR) size. Specific scoliosis physiotherapy was used, and the average follow-up period was 28.1 ± 14.5 months. Changes in ATR, Cobb angle, and functional length of the lower limbs pre- and post-treatment were statistically analyzed across three age groups (6-9, 10-12, and 13-16 years) and three scoliosis locations. Results: Significant effectiveness of early rehabilitation was observed in the high-risk group of children aged 6-9 years. In the medium-risk group, significant reductions in ATR were observed in both the 6-9 and 10-12 age groups across all three scoliosis locations. Additionally, there was a significant decrease in the Cobb angle in the thoracolumbar region and a significant reduction in lower limb inequality across all age groups and scoliosis locations. Conclusions: The early implementation of specific physiotherapy may enhance the efficacy of idiopathic scoliosis treatment by attenuating factors contributing to its progression.

The immediate effect of simulating leg-length discrepancy on spinal posture and pelvic position: a cross-over designed study

Leg-length discrepancy (LLD) is a common condition that may cause posture changes and clinical consequences. Rasterstereography is a valid and reliable method that analyzes posture without radiation exposure and invasive procedures. This study aimed to assess the immediate effect of artificial LLD on pelvic position and spinal posture in athletes. Twenty-four elite karate athletes (14 men, 10 women) were included in the study. Sagittal imbalance, coronal imbalance, pelvic obliquity, pelvic torsion angle, thoracic kyphosis angle and lumbar lordosis angle were measured at different artificial LLD heights (5 -10 -15 -20 mm). Statistical analysis was performed with One-Way ANOVA with repeated measures or Friedman test. In cases where there were significant differences, pairwise comparisons were performed with least significant differences (LSD) test or Wilcoxon signed rank test. There were statistically significant differences in pelvic obliquity (p = 0.001), pelvic torsion (p = 0.001) and lumbar lordosis (p = 0.001) with varying LLD. However, there was no significant difference in sagittal imbalance, coronal imbalance and thoracic kyphosis angle. It has been observed that even a 5-mm LLD causes pelvic position and spinal posture changes. Future studies detecting these changes in populations with LLD via rastersterography may prevent possible musculoskeletal disorders.

The Immediate Effects of Muscle Energy Technique in Chronic Low Back Pain Patients with Functional Leg Length Discrepancy: A Randomized and Placebo-Controlled Trial

This study was conducted to determine the effect of muscle energy technique (MET) on pelvic alignment, leg length, pain, and fatigue in chronic low back pain (CLBP) patients with leg length discrepancy (LLD). Forty-two CLBP patients with LLD volunteered to participate and were randomly assigned to the MET group (n = 21) and placebo group (n = 21). The intervention group performed three METs with 5 s of isometric contraction and 30 s of rest once, and the placebo group performed three times the placebo-MET, maintaining the same posture as the MET group without muscle isometric contraction. X-ray equipment, tape measure, and visual analog scale were used to evaluate pelvic alignment, leg length, pain, and fatigue before and after each intervention. In comparison pre- and postintervention, only the MET group showed significant changes in pelvic alignment, leg length, pain, and fatigue (p < 0.05). In comparison between groups, there were significant differences in all variables (pelvic alignment, leg length, pain, fatigue) (p < 0.05). The results of this study confirmed the therapeutic effect of MET for improving pelvic alignment, functional LLD, pain, and fatigue in CLBP patients with functional LLD. Future research is needed to evaluate the long-term effect on more chronic low back pain patients.

Early results of a novel modular knee arthrodesis implant after uncontrolled periprosthetic knee joint infection

AIM

The aim of this study is to evaluate the functional outcomes and complications after non-fusion knee arthrodesis with a modular segmental intramedullary implant used for infected total knee arthroplasty revisions.

METHODS

A retrospective review of the patients who had been surgically treated with a modular intramedullary arthrodesis implant for recurrent infection after revision TKA between January 2016 and February 2020 were included. The indications for arthrodesis were failed infected TKA with massive bone loss, deficient extensor mechanism and poor soft tissue coverage that precluded joint reconstruction with revision TKA implants. Clinical outcomes were assesed with visual analogue scale for pain (pVAS), Oxford knee score (OKS) and 12-item short form survey (SF-12). Full-length radiographs were used to verify limb length discrepancies (LLD).

RESULTS

Fourteen patients (4 male and 10 female) patients with a mean age of 69.3 (range, 59 to 81) years at time of surgery were available for final follow-up at a mean of 28.8 months (range, 24-35 months). All clinical outcome scores improved at the final follow-up (pVAS, 8.5 to 2.6, p = .01; OKS, 12.6 to 33.8, p = .02; SF-12 physical, 22.9 to 32.1, p = .01 and SF-12 mental, 27.7 to 40.2, p = .01). The mean LLD was 1.0 cm (range, + 15 - 2.3 cm). Re-infection was detected in three patients (21.4%). Two patients were managed with suppressive antibiotic treatment and a third patient required repeat 2-stage revision procedure. In one patient, a periprosthetic femur fracture was observed and treated with plate osteosynthesis.

CONCLUSION

Uncontrolled infection after total knee arthroplasty can be effectively treated with arthrodesis using a modular intramedullary nail and satisfactory functional results can be obtained.

LEVEL OF EVIDENCE

Level 4, Retrospective cohort study.

Influence of Lateral Sitting Wedges on the Rasterstereographically Measured Scoliosis Angle in Patients Aged 10-18 Years with Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional axial deviation of the spine diagnosed in adolescence. Despite a long daily sitting duration, there are no studies on whether scoliosis can be positively influenced by sitting on a seat wedge. For the prospective study, 99 patients with AIS were measured with the DIERS formetric III 4D average, in a standing position, on a level seat and with three differently inclined seat wedges (3°, 6° and 9°). The rasterstereographic parameters 'scoliosis angle' and 'lateral deviation RMS' were analysed. The side (ipsilateral/contralateral) on which the optimal correcting wedge was located in relation to the lumbar/thoraco-lumbar convexity was investigated. It was found that the greatest possible correction of scoliosis occurred with a clustering in wedges with an elevation on the ipsilateral side of the convexity. This clustering was significantly different from a uniform distribution (p < 0.001; chi-square = 35.697 (scoliosis angle); chi-square = 54.727 (lateral deviation RMS)). It should be taken into account that the effect of lateral seat wedges differs for individual types of scoliosis and degrees of severity. The possibility of having a positive effect on scoliosis while sitting holds great potential, which is worth investigating in follow-up studies.

Vertebral Rotation in Functional Scoliosis Caused by Limb-Length Inequality: Correlation between Rotation, Limb Length Inequality, and Obliquity of the Sacral Shelf

BACKGROUND

Scoliosis is a structured rotatory deformity of the spine defined as >10° Cobb. Functional scoliosis (FS) is a curve < 10° Cobb, which is non-rotational and correctable. FS is often secondary to leg length inequality (LLI). To observe vertebral rotation (VR) in functional scoliosis due to LLI, one must demonstrate a correlation between LLI, sacral shelf inclination (SSI), and VR and discover a predictive value of LLI capable of inducing rotation.

METHODS

We studied 89 patients with dorso-lumbar or lumbar curves < 15° Cobb and radiographs of the spine and pelvis. We measured LLI, SSI, and VR. The patients were divided into VR and without rotation (WVR) groups. Statistical analysis was performed.

RESULTS

The mean LLI value was 6.5 ± 4.59 mm, and the mean SSI was 2.8 ± 2.53 mm. The mean value of LLI was 5.2 ± 4.87 mm in the WVR group and 7.4 ± 4.18 mm in the VR group. The mean SSI value for WVR was 1.4 ± 2.00 and that for VR was 3.9 ± 2.39. For each mm of LLI, it was possible to predict 0.12° of rotation. LLI ±5 mm increased the probability of rotation (R2.08 p < 0.0016), while this was ±2 mm for SSI (R2 0.22 p < 0.01). Each mm of LLI corresponded to 0.3 mm of SSI (R2 0.29, p < 0.01).

CONCLUSIONS

FS secondary to LLI can cause VR, and 5 mm of LLI can cause SSI and rotation.

The radiation dose, clinical and anatomical implications of erect lumbar spine radiography: A single centre pre-post implementation evaluation

INTRODUCTION

Lumbar radiographs remain a common imaging examination despite strategies to reduce their use. Many authors have demonstrated benefits in changing from traditional supine and recumbent lateral projections to a prone and/or erect orientation. Despite evidence of clinical and radiation dose optimisation, widespread adoption of these strategies has stalled. This article describes the single-centre implementation and evaluation of erect PA and lateral projections.

METHOD

This was an observational study pre- and post-implementation of an erect imaging protocol. Patient BMI, image field size, source image and source object distances and DAP were collected together with assessment of radiographic spinal alignment and disc space demonstration. Effective dose was calculated with organ specific doses.

RESULTS

76 (53.5%) patients were imaged in the supine AP and recumbent lateral position, 66 (46.5%) had erect PA and lateral radiographs. Despite the larger BMI of the erect cohort and similar field sizes, effective dose was lower in the PA position by an average of 20% (p < 0.05), however, no significant difference in lateral dose. Anatomical improvements were evident with greater visualisation of intervertebral disc spaces in the PA erect (t = -9.03; p < .001) and lateral (t = -10.298; p < .001) orientations. Erect PA radiographs demonstrated a leg length discrepancy in 47.0% (0.3-4.7 cm) and a scoliosis in 21.2% of cases, with a significant link between these findings (r (64) = 0.44; p < .001).

CONCLUSION

Erect lumbar spine radiography provides information on clinical outcomes not available with recumbent projections. The improvements in anatomical visualisation and radiation dose reduction supports the local change in practice.

IMPLICATIONS FOR PRACTICE

- Erect imaging can reduce effective dose with an optimised acquisition protocol - additional pathological information can be revealed by the erect posture. - postural awareness is critical to interpret images accurately.

Induced leg length inequality affects pelvis orientation during upright standing immediately following a sit-to-stand transfer: a pre-post measurement study

BACKGROUND

Leg length inequality (LLI) greater than 20 mm has been associated with low back pain (LBP) and its correction is clinically recommended. Much less is known about the biomechanical effects that LLI below 15 mm has on pelvis orientation.

METHODS

Twenty-two adult participants (8 female) aged between 18 and 30 years without LBP were enrolled in the study and completed a series of sit-to-stand trials with no heel-lift (0 mm baseline) and heel-lifts of varying heights (5, 9 and 12 mm) placed in their right shoe. Three-dimensional kinematic data were obtained from the lower extremities, pelvis and thorax. Additional kinematic data were obtained from the left and right sides of the pelvis. The global orientation of the whole pelvis and relative orientation between the left and right sides of the pelvis were obtained in upright standing immediately upon completion of the sit-to-stand movement. Repeated measures ANOVAs were used to detect differences in sample means across the different levels of heel-lift (0, 5, 9, and 12 mm). The tests for within-subject effects determined overall significant differences between the means at the different levels of heel-lift induced LLI. Partial Eta-Squared was used to express the size for the main effect of heel-lift height. For each level of heel-lift, the estimated marginal mean and 95% confidence interval (95%CI) values of pelvis angles were illustrated graphically.

RESULTS

Left frontal plane rotation of the pelvis increased (p = 0.001), that is, the left side of the pelvis was lower than the right side of the pelvis, and anterior tilt of the pelvis decreased (p = 0.020) with a heel-lift height (applied on the right) as low as 5 mm. A significant main effect of heel-lift was only observed for the norm of rotations about all three axes for relative-pelvis orientation (p = 0.034). Post-hoc analyses did not reveal any statistically significant differences between the heel-lifts and the 0 mm baseline (p≥0.072).

CONCLUSION

These findings suggest that correcting leg length inequality below the recommended threshold of 20 mm may influence pelvic orientation. Future work can investigate the effects of the altered orientations on spine loading and the clinical effects of corrections to minor leg length inequality.

Standard values of the upper body posture in healthy adults with special regard to age, sex and BMI

In order to classify and analyze the parameters of upper body posture in clinical or physiotherapeutic settings, a baseline in the form of standard values with special regard to age, sex and BMI is required. Thus, subjectively healthy men and women aged 21-60 years were measured in this project. The postural parameters of 800 symptom-free male (n = 397) and female (n = 407) volunteers aged 21-60 years (Ø♀: 39.7 ± 11.6, Ø ♂: 40.7 ± 11.5 y) were studied. The mean height of the men was 1.8 ± 0.07 m, with a mean body weight of 84.8 ± 13.1 kg and an average BMI of 26.0 ± 3.534 kg/m². In contrast, the mean height of the women was 1.67 ± 0.06 m, with a mean body weight of 66.5 ± 12.7 kg and an average BMI of 23.9 ± 4.6 kg/m². By means of video rasterstereography, a 3-dimensional scan of the upper back surface was measured when in a habitual standing position. The means or medians, confidence intervals, tolerance ranges, the minimum, 2.5, 25, 50, 75, 97.5 percentiles and the maximum, plus the kurtosis and skewness of the distribution, were calculated for all parameters. Additionally, ANOVA and a factor analyses (sex, BMI, age) were conducted. In both sexes across all age groups, balanced, symmetrical upper body statics were evident. Most strikingly, the females showed greater thoracic kyphosis and lumbar lordosis angles (kyphosis: Ø ♀ 56°, Ø♂ 51°; lordosis: Ø ♀ 49°, Ø♂ 32°) and lumbar bending angles (Ø ♀ 14°, Ø♂ 11°) than the males. The distance between the scapulae was more pronounced in men. These parameters also show an increase with age and BMI, respectively. Pelvic parameters were independent of age and sex. The upper body postures of women and men between the ages of 21 and 60 years were found to be almost symmetrical and axis-conforming with a positive correlation for BMI or age. Consequently, the present body posture parameters allow for comparisons with other studies, as well as for the evaluation of clinical (interim) diagnostics and applications.

Effect of Leg Length Discrepancy on Dynamic Gait Stability

Objectives

: It is unclear whether the increased center of mass lateral shift during gait induced by leg length difference induces lateral instability. The purpose of this study was to investigate the effect of leg length discrepancy (LLD) on dynamic gait stability and the compensatory kinematic and dynamic strategies for this effect by using the extrapolated center of mass and margin of stability.

Methods

: Nineteen healthy male participants walked without insoles (no LLD condition; 0 cm) and with added insoles (LLD condition; 3 cm). Kinematic and kinetic data were analyzed using a three-dimensional motion analyzer and force plates; the values were compared between the two conditions. Correlation analysis was performed on the parameters and the margin of stability and significant changes were identified.

Results

Compared with the no-LLD condition, in the LLD condition, lateral stability was maintained on both the short leg side and the long leg side. Nonetheless, changes in joint angles and muscle activity on the frontal plane were observed on the short leg side, although the correlations were not significant. On the long leg side, a moderate negative correlation was found between the lateral flexion angle of the trunk and the margin of stability (r=-0.56, P=0.011).

Conclusions

The short leg side may compensate for lateral stability by complex changes in joint angles and muscle activity, and the long leg side may compensate for lateral stability by actively adjusting the trunk lateral flexion angle.

Correlation Analysis between Leg-length Discrepancy and Lumbar Scoliosis Using Full-length Standing Radiographs

Aim

When a leg-length discrepancy (LLD) is severe enough, it can result in lumbar scoliosis and other postural defects. To our knowledge, no study has demonstrated associations between LLD and lumbar curvature using full-length standing radiographs of the lower limbs and lumbar spine. This study aimed to examine the correlations between LLD and lateral curvature of the lumbar spine using standing radiographs.

Materials and methods

Full-length standing radiographs of the lower limbs and spinal column of 113 participants (age range: 10-65 years) obtained between November 2006 and September 2019 were reviewed. Leg length was measured as the linear distance from the centre of the femoral head to the centre of the tibial plafond and converted to millimetres using a radiographic ruler captured in the images. Leg-length discrepancy was analysed as the absolute difference (mm) between the left and right leg lengths. Inequality was also evaluated as leg-length discrepancy ratio (LLDR), calculated as leg-length discrepancy/length of the unaffected (longer) leg × 100 (%). Lateral lumbar curvature was evaluated with the Cobb angle (°). The association between LLD or LLDR and lumbar Cobb angle was analysed by correlation analysis. Statistical analysis was performed by simple regression in SPSS.

Results

Both LLD and LLDR exhibited a robust and positive correlation with lumbar Cobb angle (γ = 0.53, γ = 0.62), as illustrated by the following regression equations: lumbar Cobb angle (°) = 0.316 × leg-length discrepancy (mm) + 2.83 and lumbar Cobb angle (°) = 2.19 × leg-length discrepancy ratio (%) + 3.0.

Conclusion

Using objective imaging data, we found that the lumbar Cobb angle tends to be >10° if the difference in leg lengths is >20 mm.

How to cite this article

Hamada T, Matsubara H, Kato S, et al. Correlation Analysis between Leg-length Discrepancy and Lumbar Scoliosis Using Full-length Standing Radiographs. Strategies Trauma Limb Reconstr 2022;17(3):144-147.

Biomechanical evaluation and comparison of clinically relevant versus non-relevant leg length inequalities

BACKGROUND

Leg length inequalities are a frequent condition in every population. It is common clinical practice to consider LLIs of 2 cm and more as relevant and to treat those. However, the amount of LLIs that need treatment is not clearly defined in literature and the effect of real LLIs on the musculoskeletal system above and below 2 cm have not been studied biomechanically before.

METHODS

By using surface topography, we evaluated 32 patients (10 females, 22 male) with real LLIs of ≥ 2 cm (mean: 2.72 cm; n = 10) and compared their pelvic position and spinal posture to patients with LLIs < 2 cm (mean: 1.24 cm; n = 22) while standing and walking. All patients were measured with a surface topography system during standing and while walking on a treadmill. To compare patient groups, we used Student t-tests for independent samples.

RESULTS

Pelvic obliquity was significantly higher in patients with LLI ≥ 2 cm during the standing trial (p = 0.045) and during the midstance phase of the longer leg (p = 0.023) while walking. Further measurements did not reveal any significant differences (p = 0.06-0.706).

CONCLUSIONS

The results of our study suggest that relevant LLIs of ≥ 2 cm mostly affect pelvic obliquity and do not lead to significant alterations in the spinal posture during a standing trial. Additionally, we demonstrated that LLIs are better compensated when walking, showing almost no significant differences in pelvic and spinal posture between patients with LLIs smaller and greater than 2 cm. This study shows that LLIs ≥ 2 cm can still be compensated; however, we do not know if the compensation mechanisms may lead to long-term clinical pathologies.

Leg Length Discrepancy and Nonspecific Low Back Pain: 3-D Stereophotogrammetric Quantitative Posture Evaluation Confirms Positive Effects of Customized Heel-Lift Orthotics

Background: The literature reports evidence of leg length discrepancy (LLD) associated with musculoskeletal disorders, alterations in spinopelvic alignment, and body posture, leading to low back pain and lumbar scoliosis. The most common conservative treatment for LLD is the use of internal or external shoe lifts although no treatment guidelines have been established.

Aim: The study aimed to contribute to low back pain–LLD relationship comprehension, highlighting the benefits of LLD correction in the nonspecific low back pain (NSLBP) population.

Methods: A cross-sectional observational study recruited a cohort of 80 NSLBP patients (48 females, 32 males) with LLD, age (μ = 35 ± 17.2). Entire body posture, including 3-D spine shape reconstruction, was measured using a nonionizing 3-D optoelectronic stereophotogrammetric approach. After the first 3-D posture evaluation, patients were provided with customized orthotics, including 100% LLD heel lift correction. No other therapeutic interventions were considered. Pain level was assessed using the numerical pain rating scale (NPRS). The gender, age-related, and time-dependent effects of LLD equalization treatment in NSLBP patients was investigated during 2 years of follow-up. The statistical analysis was performed at the global level using multivariate methods by Hotelling T² tests and intrasubject-level using t-test.

Results and Discussion: An initial average NPRS = 7.8 was determined. In the medium-term follow-up group (4 months), the NPRS dramatically decreased (NPRS = 1.1). The pain disappeared in the long-term (2 years) follow-up group (NPRS = 0). The study results highlight that LLD equalization treatment led to clear statistically significant improvements in all the postural parameters of the frontal plane, including the underfoot load asymmetry. No worsening has been detected. An adaptation period long enough is needed to obtain progressive pain relief improvements and structural posture changes. Younger NSLBP patients showed slightly better improvements than older ones. Minimal differences between healthy young adults’ and NSLBP patients’ postures were found either in natural erect standing posture or when LLD equalization is applied.

Conclusion: Heel-lift customized orthotics with 100% LLD correction are an effective short- and long-term treatment in patients with nonspecific LBP, inducing pain symptom recession and stimulating the improvement of postural parameters without contraindications.

Research and development of 3D printing orthotic insoles and preliminary treatment of leg length discrepancy patients

BACKGROUND:

Leg length discrepancy (LLD) can cause abnormal posture, muscle and/or joint pains, which leads to walking difficulties. The common treatment is to use a shoe lift on the shorter leg side, but this has unsatisfying results.

OBJECTIVE:

Through research and development, we created 3D printing orthotic insoles for LLD patients and aimed to improve their symptoms.

METHODS:

1. Research and development of 3D printing orthotic insole: (1) foot scan and data acquisition; (2) insole software modeling; (3) 3D printing insole using TPU materials, and (4) post-processing. 2. Clinical observation: we customized insoles for LLD patients and required them to wear them while walking. We conducted general inquiries and a functional evaluation before and after 12 weeks of wearing insoles.

RESULTS:

There are seven complete cases. The joint and lower back pains were alleviated. The stride frequency, stride and pace were improved in all seven cases. Patients’ overall health condition improved significantly.

CONCLUSIONS:

The 3D printing orthotic insoles are made with clear procedures and practical operability. By wearing insoles, patients’ muscle and/or joint pains were relieved and their gaits were improved.

Intra and intersession repeatability and reliability of dynamic parameters in pressure platform assessments on subjects with simulated leg length discrepancy. A cross-sectional research

BACKGROUND

Leg length discrepancy (LLD) may play a key role in exercise biomechanics. Although the Podoprint platform has been used in dynamic pressure studies, there are no data regarding the reliability and repeatability of dynamic measurements under simulated LLD conditions.

OBJECTIVES

To determine the intra and intersession repeatability and reliability of dynamic parameters of the Podoprint pressure platform under simulated LLD conditions.

DESIGN AND SETTING

Observational cross-sectional study at a public university.

METHODS

Thirty-seven healthy volunteers participated in this study. LLD was simulated using ethyl vinyl acetate plantar lifts with heights of 5 mm, 10 mm, 15 mm and 20 mm located under the right shoe of each volunteer. The procedure was performed to capture the dynamic parameters of each participant under five different simulated LLD conditions. Stance time, mean pressure and peak pressure measurements were registered in three trials for each foot and each LLD level. Data were collected during two separate testing sessions, in order to establish intrasession and intersession reliability.

RESULTS

The intraclass correlation coefficients (ICCs) for intrasession reliability ranged from 0.775 to 0.983 in the first session and from 0.860 to 0.985 in the second session. The ICCs for intersession reliability ranged from 0.909 to 0.990. Bland-Altman plots showed absence of systematic measurement errors.

CONCLUSIONS

The results from this study indicate that the Podoprint platform is a reliable system for assessing dynamic parameters under simulated LLD conditions. Future studies should evaluate plantar pressures under LLD conditions, in association with exercise, biomechanics and musculoskeletal disorders.

The Effect of Simulated Leg-Length Discrepancy on the Dynamic Parameters of the Feet during Gait-Cross-Sectional Research

Background: The effect of Leg-Length Discrepancy (LLD) on dynamic gait parameters has been extensively discussed. Podobarography is the study of foot-to-ground pressure distribution. It has been used to test plantar footprint deviations that could reveal pathology. Purpose: The aim of this study is to determine the effects of simulated LLD on dynamic gait parameters measured with a pressure platform in healthy subjects. Methods: Thirty-seven healthy subjects participated in observational cross-sectional research. A procedure was performed to capture the dynamic parameters of each participant under five different simulated LLD conditions. Support time, mean pressure, and peak pressure measures were registered on three trials for each foot and LLD level per session. An analysis of variance (ANOVA) test for repeated measures was performed to check for differences between the different simulated LLD levels. Results: The stance time of the short leg had no significant changes. The stance time of the long leg increased by 3.51% (p < 0.001), mean pressure of the short leg increased by 1.23% (p = 0.005), and decreased by 5.89% in the long leg (p < 0.001). Peak pressure of the short leg decreased by 2.58% (p = 0.031) and the long leg decreased by 12.11% (p < 0.001). Conclusions: This study demonstrates that increasing LLD causes an asymmetrical foot-loading pattern, with decreased mean and peak pressure on the longer limb, and consequently an overload on the short side. Furthermore, an increasing LLD causes increased stance time on the long leg.

Radiophobia Overreaction: College of Chiropractors of British Columbia Revoke Full X-Ray Rights Based on Flawed Study and Radiation Fear-Mongering

Fears over radiation have created irrational pressures to dissuade radiography use within chiropractic. Recently, the regulatory body for chiropractors practicing in British Columbia, Canada, the College of Chiropractors of British Columbia (CCBC), contracted Pierre Côté to review the clinical use of X-rays within the chiropractic profession. A "rapid review" was performed and published quickly and included only 9 papers, the most recent dating from 2005; they concluded, "Given the inherent risks of radiation, we recommend that chiropractors do not use radiographs for the routine and repeat evaluation of the structure and function of the spine." The CCBC then launched an immediate review of the use of X-rays by chiropractors in their jurisdiction. Member and public opinion were gathered but not presented to their members. On February 4, 2021, the College announced amendments to their Professional Conduct Handbook that revoked X-ray rights for routine/repeat assessment and management of patients with spine disorders. Here, we highlight current and historical evidence that substantiates that X-rays are not a public health threat. We also point out critical and insurmountable flaws in the single paper used to support irrational and unscientific policy that discriminates against chiropractors who practice certain forms of evidence-based X-ray-guided methods.

Influence of design of dentist's chairs on body posture for dentists with different working experience

BACKGROUND

Musculoskeletal disorders (MSD) are a common health problem among dentists. Dental treatment is mainly performed in a sitting position. The aim of the study was to quantify the effect of different ergonomic chairs on the sitting position. In addition, it was tested if the sitting position of experienced workers is different from a non-dental group.

METHODS

A total of 59 (28 m/31f) subjects, divided into two dentist groups according to their work experience (students and dentists (9 m/11f) < 10 years, dentists (9 m/10f) ≥ 10 years) and a control group (10 m/10f) were measured. A three-dimensional back scanner captured the bare back of all subjects sitting on six dentist's chairs of different design. Initially, inter-group comparisons per chair, firstly in the habitual and secondly in the working postures, were carried out. Furthermore, inter-chair comparison was conducted for the habitual as well as for the working postures of all subjects and for each group. Finally, a comparison between the habitual sitting posture and the working posture for each respective chair (intra-chair comparison) was conducted (for all subjects and for each group). In addition, a subjective assessment of each chair was made. For the statistical analysis, non-parametric tests were conducted and the level of significance was set at 5%.

RESULTS

When comparing the three subject groups, all chairs caused a more pronounced spinal kyphosis in experienced dentists. In both conditions (habitual and working postures), a symmetrical sitting position was assumed on each chair. The inter-chair comparisons showed no differences regarding the ergonomic design of the chairs. The significances found in the inter-chair comparisons were all within the measurementerror and could, therefore, be classified as clinically irrelevant. The intra-chair comparison (habitual sitting position vs. working sitting position) illustrated position-related changes in the sagittal, but not in the transverse, plane. These changes were only position-related (forward leaned working posture) and were not influenced by the ergonomic sitting design of the respective chair. There are no differences between the groups in the subjective assessment of each chair.

CONCLUSIONS

Regardless of the group or the dental experience, the ergonomic design of the dentist's chair had only a marginal influence on the upper body posture in both the habitual and working sitting postures. Consequently, the focus of the dentist's chair, in order to minimize MSD, should concentrate on adopting a symmetrical sitting posture rather than on its ergonomic design.

Changes in muscle activities and kinematics due to simulated leg length inequalities

Muscle imbalances are a leading cause of musculoskeletal problems. One example are leg length inequalities (LLIs). This study aimed to analyze the effect of different (simulated) LLIs on back and leg muscles in combination with kinematic compensation mechanics. Therefore, 20 healthy volunteers were analyzed during walking with artificial LLIs (0-4 cm). The effect of different amounts of LLIs and significant differences to the reference condition without LLI were calculated of maximal joint angles, mean muscle activity, and its symmetry index. While walking, LLIs led to higher muscle activity and asymmetry of back muscles, by increased lumbar lateral flexion and pelvic obliquity. The rectus femoris showed higher values, independent of the amount of LLI, whereas the activity of the gastrocnemius on the shorter leg increased. The hip and knee flexion of the long leg increased significantly with increasing LLIs, like the knee extension and the ankle plantarflexion of the shorter leg. The described compensation mechanisms are explained by a dynamic lengthening of the short and shortening of the longer leg, which is associated with increased and asymmetrical muscle activity. Presenting this overview is important for a better understanding of the effects of LLIs to improve diagnostic and therapy in the future.

Inertial measurement units for the detection of the effects of simulated leg length inequalities

Background

Leg length inequalities (LLI) are a common condition that can be associated with detrimental effects like low back pain and osteoarthritis. Inertial measurement units (IMUs) offer the chance to analyze daily activities outside a laboratory. Analyzing the kinematic effects of (simulated) LLI on the musculoskeletal apparatus using IMUs will show their potentiality to improve the comprehension of LLI.

Methods

Twenty healthy participants with simulated LLI of 0-4 cm were analyzed while walking with an inertial sensor system (MyoMotion). Statistical evaluation of the peak anatomical angles of the spine and legs were performed using repeated measurement (RM) ANOVA or their non-parametric test versions (Friedman test).

Results

Lumbar lateral flexion and pelvic obliquity increased during the stance phase of the elongated leg and decreased during its swing phase. The longer limb was functionally shortened by higher hip and knee flexion, higher hip adduction, dorsiflexion, and lower ankle adduction. Finally, the shorter leg was lengthened by higher hip and knee extension, hip abduction, ankle plantarflexion, and decreased hip adduction.

Conclusion

We found differing compensation strategies between the different joints, movement planes, gait phases, and amounts of inequality. Overall the shorter leg is lengthened and the longer leg is shortened during walking, to retain the upright posture of the trunk. IMUs were helpful and precise in the detection of anatomical joint angles and for the analysis of the effects of LLI.

Systematic changes of the static upper body posture with a symmetric occlusion condition

Background

Temporary occlusal changes and their influence on the upper body statics are still controversially discussed. Furthermore, concrete statements on whether age- or gender-specific differences in neurophysiological reactions exist are missing. Therefore, it is the aim of this study to evaluate the immediate effects of a symmetrical occlusion blocking on the upper body posture. These effects shall be investigated for both genders and for a larger age range.

Methods

In this study, 800 (407f/393 m) subjects volunteered aged from 21 to 60 years. Both genders were divided into four age groups according to decades. The three-dimensional upper body posture was measured by using the rasterstereography (ABW-Bodymapper). The habitual static posture was measured in two dental occlusion conditions (a) in rest position and (b) symmetrical blocking in the bicuspid region by cotton rolls.

Results

A significant reduction of the trunk length (0.72 mm; p <  0.001), an increase of the lumbar (0.30°; p <  0.001) and the thoracic bending angle (0.14°; p = 0.001), a reduction of the spinal forward decline (0.16°; p <  0.001) and a reduction of the scapular distance (0.36 mm; p = 0.001) was found. Gender-specific reactions can only be recorded in scapular distance, in that regard men reduce this distance while over all age groups women did not show a significant change.

Discussion

Slight gender- and age-independent reactions due to a symmetric occlusion blockade are shown: A gender independent reaction of the spinal related variables in the sagittal plane (thoracic and lumbar flexion angle, trunk length, spinal forward decline). In addition, a gender specific change of the shoulder blade distance could be observed, where men reduced the distance while female did not show a change. However, since these reactions are of a minimum amount, it can be concluded that neurophysiological compensation mechanisms work equally well regardless of age and sex, and the upper body posture of healthy people changes only very slightly due to a temporarily symmetrical altered bite position.

Evaluating the role of surface topography in the surveillance of scoliosis

STUDY DESIGN

Literature review.

OBJECTIVE

To review the history, modern uses, limitations, and future direction of surface topography (ST) in surveillance of scoliosis. Spinal deformities, including scoliosis, can be characterized using measurements such as the Cobb angle, lateral curvature, and vertebral rotation. The gold standard for diagnosis and surveillance of such deformities utilizes radiographic images. To minimize repeated radiation exposure, many systems have been developed utilizing ST. ST measures local deviations of a surface from a flat plane. Applying this concept to spinal deformities, ST can non-radiographically study the 3-dimensional shape of the back. One ST system, rasterstereography, projects parallel white light lines onto a patient's back and analyzes line distortion with a camera. While radiography has long been considered the primary diagnostic tool for scoliosis, rasterstereography may possess alternative or complementary benefits in monitoring scoliosis and other diseases.

METHODS

A comprehensive literature review was performed on the history, development, and validity of ST. The advantages and limitations of this technique were compared to those of radiography.

RESULTS

While the initial goal of ST, designing a system to accurately reproduce the Cobb angle, was not successful, research efforts over the last 40 years have attempted to improve this correlation. ST technologies, including rasterstereography and the Formetric ST System, currently play important roles in scoliosis surveillance, research, and minimizing radiation exposure in longitudinal care of patients. Such technologies are also useful as an adjunct to X-rays for monitoring disease progression, especially in Parkinson's disease.

CONCLUSION

Despite its limitations, ST has proven useful across multiple fields of medicine. It is a safe and cost-effective tool for long-term surveillance of scoliosis and early detection of progressive disease. With technological improvements, the Formetric System will become a critical alternative in dynamic spinal motion and gait analysis.

LEVEL OF EVIDENCE

N/A.

Standard reference values of the upper body posture in healthy male adults aged between 41 and 50 years in Germany

BACKGROUND

Classifications of posture deviations are possible when they can be compared to the standard values for healthy persons. Standard values for healthy male adults aged between 41 and 50 years are currently missing.

METHODS

100 healthy volunteers (41-50 years old; 45.37 ± 3.06 years) were included in the study. Their body weight ranged from 68 to 132 kg (88.76 ± 15.93 kg), their heights from 1.64 to 2.0 m (1.81 ± 0.07 m) and the Body Mass Index (BMI) ranged from 19.0 kg/m² to 37.7 kg/m² (26.2 ± 3.96 kg/m²). A three-dimensional back scan was performed to quantify the upper back posture during habitual standing. The upper and lower limit for 95% of the tolerance regions and the left and right limit of the confidence interval were calculated.

RESULTS

The upper body posture of the subjects was close to the symmetry, or 0°, axis. There was a moderate ventral upper body inclination with a slight left lateral axial deviation and rotation of the spine to the right. An enhanced kyphotic posture was observed in the sagittal plane in the area of the thoracic spine. The shoulder and pelvis areas were almost balanced.

CONCLUSION

Healthy males between 41 and 50 years were found to have an almost balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. These values allow a comparison with other studies for control and patient data and may serve as basis in both clinical practice and scientific studies.

Influence of leg length inequalities on pelvis and spine in patients with total hip arthroplasty

Background

Leg length inequalities (LLIs) are a common finding in patients with a total hip arthroplasty (THA). Therefore, we compared the effects of simulated LLIs in patients with total hip arthroplasty (THA) with a matched control group.

Research question

Do LLIs lead to different effects on the musculoskeletal apparatus of patients with a THA then in a control group?

Methods

In 99 patients with a THA the effects of simulated LLIs were compared to a matched control group of 101 subjects without a hip arthroplasty. First, we compared methods for LLI quantification (tape measurements, pelvic x- ray and rasterstereography). Second, the effects of simulated LLIs on the spine and pelvis were evaluated in both groups using surface topography. LLIs of 5, 10, 15, 20 and 30 mm were simulated on both sides with a simulation platform. The changes of pelvic position (pelvic obliquity & pelvic torsion) and the effects on spinal posture (surface rotation & lateral deviation) were measured and analysed using a surface topography system.

Results

Mean LLI measured with a tape was 0.9 mm (SD +/- 14.8). Mean pelvic obliquity measured on x-rays was 1.2 mm (SD +/- 11.6) and with surface topography 0.9 mm (SD +/- 7.9). Simulated LLIs resulted in significant changes of pelvic position and spinal posture in the patient and control group. Interestingly, our study showed that simulated LLIs lead to greater changes in pelvic position (p<0.05) in patients with a THA.

Significance

This is the first study to demonstrate that LLIs might have a greater impact on the pelvic position of THA patients than in native hips, which could indicate that LLIs do need to be compensated differently in patients with THA than in patients without a THA.

Comparison of two different designs of forefoot off-loader shoes and their influence on gait and spinal posture

BACKGROUND

The purpose of forefoot off-loader shoes (FOS) is to unload the operated region of the foot in order to allow early mobilization and rehabilitation. However, little is known about the actual biomechanical effects of different designs of FOS on gait, pelvis and spine.

RESEARCH QUESTION

Aim of this study was to analyse and compare the effects of two different designs of forefoot unloader shoes.

METHODS

Ortho-Wedge (FOS A) and Relief-Dual® (FOS B) were evaluated in this study during standing and while walking. Changes of the pelvic position and spinal posture were measured with a surface topography system and an instrumented treadmill. Gait phases were detected automatically by a built-in pressure plate.

RESULTS

Both FOS resulted in a significant increase of pelvic obliquity, pelvic torsion, lateral deviation and surface rotation (p < 0.001) while standing. Between both shoe models, pelvic obliquity and lateral deviation (p < 0.05) were significantly different. During walking, both FOS had a significant effect on spine and pelvis (p < 0.05), however only minor differences were found between the designs. All gait parameters were affected more, wearing FOS A than B. Step length were significantly longer by wearing FOS (p < 0.005). However stance phase raised and swing phase is reduced on the leg wearing FOS A (p < 0.001).

SIGNIFICANCE

The study showed that FOS lead to significant changes in pelvic position and spinal posture during standing and while walking. A compensating shoe on the contralateral side is therefore recommend. Gait parameters however were affected more by the traditional FOS A half-shoe. The sole- design and shape of FOS B leads to a more physiological roll-over of the foot.

Effect of inherent tibial asymmetry on leg length discrepancy measurements after intramedullary nailing of comminuted femoral shaft fractures

Introduction: Locked intramedullary nailing (IMN) is the standard treatment for femoral shaft fractures in adults with high rates of union and relatively low rates of complications. Leg length discrepancy (LLD) after IMN of femoral shaft fractures is common, and is reported in 20–43% of cases. A known surgical challenge when trying to obtain equal leg lengths is comminuted fracture, which results in a loss of bony landmarks that guide reduction. The purpose of this study was to assess the effect of inherent tibial asymmetry on LLD measurements after IMN.

Methods: Postoperative CT scanograms were performed on 79 consecutive patients after locked IMN for comminuted femoral shaft fracture. Leg lengths were determined by measurements taken from the scout view of a CT scanogram. Calculations of discrepancy were made for both femurs, tibias, and total leg length. Assessment was also made on the frequency wherein the tibial discrepancy compounded the femoral discrepancy. In situations where a limb segment was exactly symmetric to the contralateral side, the total leg was not regarded as a having compounded asymmetry.

Results: Notable discrepancies were found in tibial length that significantly departed from the null of symmetry (p < 0.0001). Forty-two patients (53.2%) were found to have a tibial asymmetry of 3 mm or more, and 20 patients (25.3%) were found to exhibit a difference of 6.3 mm or more. Median femoral discrepancy was 5.3 mm and median tibial discrepancy was 3.0 mm. Seven patients were found to be asymmetric in total leg length as a consequence of underlying tibial asymmetry. Conversely, 11 patients benefited from their tibial asymmetry, which compensated for femoral asymmetry after IMN.

Conclusion: Tibial symmetry cannot be assumed. If not accounted for, inherent tibial asymmetry may influence LLD after IMN of femur fractures.

Dynamic evaluation of simulated leg length inequalities and their effects on the musculoskeletal apparatus

BACKGROUND

Leg length inequalities (LLI) are a common problem in medicine. So far, the diagnosis and treatment are performed under static conditions. Surface Topography (ST) is an optical, non-invasive technique that uses the principle of triangulation to measure spinal posture and pelvic position. This technique offers the opportunity to detect and treat LLIs and their effects under dynamic conditions.

RESEARCH

question The aim of the study is to show that ST can detect simulated LLIs under dynamic conditions and to prove if there are differences between the effects on the human body under static and dynamic conditions.

METHODS

In the clinical study a total of 30 test subjects were examined with a ST measuring device. LLIs (1 to 4 cm) were simulated using a custom- built sandal and insoles of various thickness. The pelvic obliquity, the surface rotation and lateral deviation of the spine were detected on a treadmill under static and dynamic conditions (3 km/h).

RESULTS

Under static and dynamic conditions LLIs lead to a significant increase of all measured parameters. The pelvic obliquity reaches a significant level of p < 0.0001 under static and p = 0.0001-0.0421 under dynamic conditions. However, for all examined parameters the magnitudes of the parameters under dynamic conditions were smaller than under static conditions.

SIGNIFICANCE

The study showed that simulated LLIs also have a significant effect on the human pelvis and spine under dynamic conditions, but with a smaller magnitude than under static conditions. The human individuum is a dynamic one. Because of that, for the future it should be of great interest to use dynamic measurements to detect and treat LLIs to provide an over correction of LLIs.

Truncal changes in children with mild limb length inequality: a surface topography study

Background

Limb length Inequality (LLI) in children and adults may affect posture, gait, and several truncal parameters, and it can cause spinal scoliosis. In literature, however, there is a paucity of assessment of truncal and spinal changes due to mild LLI in children. This report presents children with LLI, and it aims to provide information in pelvic imbalance, spinal posture, and scoliotic curve, using surface topography analysis which is a novel methodological approach for this condition.

Study design

This is an ongoing prospective research study on patient series suffering LLI.

Material and method

Twenty children, attending the Scoliosis Clinic of the department, 7 boys, 13 girls, 9-15 years old, range 7.5-15, mean 15.5 years, having mild LLI, were assessed. The LLI was 0.5 to 2 cm, mean 1.2 cm. There was not any post-traumatic LLI. We evaluated the LLI in correlation to pelvic and spinal posture parameters. The 4D Formetric DIERS apparatus (4DF) was used for the surface topography assessment. The following were assessed: in the coronal plane, the coronal imbalance, the pelvic obliquity, the lateral deviation, and the 4DF scoliosis angle; in the sagittal plane, the sagittal imbalance, the 4DF kyphotic angle, the kyphotic apex, the 4DF lordotic angle, the lordotic apex, the pelvic tilt, and the trunk inclination; and in the transverse plane, the pelvis rotation, the pelvic torsion, the surface rotation, and the 4DF vertebral rotation. LLI was measured using a tape. The data were statistically analyzed, and reliability study for the LLI was also performed.

Results/discussion

The LLI was statistically significantly correlated to the 4DF reading of pelvis rotation, pelvic tilt (pelvic obliquity), and surface rotation. The scoliometer readings (angle trunk rotation ATR or trunk inclination ATI) in the lumbar region were statistically significantly correlated to the 4DF readings of pelvic tilt (pelvic obliquity). The normally symmetric truncal parameters were also statistically significantly changed (all these deviating from the line of gravity through the vertebral prominence). Interestingly, LLI was not correlated to the scoliosis angle and the scoliometer reading at the lumbar level.The following 4DF readings are presented: in the coronal plane, the coronal imbalance, pelvic obliquity, lateral deviation, and 4DF scoliosis angle; in the sagittal plane, the sagittal imbalance, kyphotic angle, kyphotic apex, lordotic angle, lordotic apex, pelvic tilt, and trunk inclination; and in the transverse plane, the pelvic rotation, pelvic torsion, surface rotation, and vertebral rotation.

Conclusions

Previous studies have reported the results after simulation of LLI in order to evaluate the effects on the pelvic balance and spinal posture parameters. This report is not a LLI simulation study but it presents the effects of mild LLI on truncal changes in the main cardinal planes in children suffering LLI. These changes undoubtedly affect not only the standing truncal posture but also the gait's economy as well.As mild LLI affects the pelvic balance and spinal posture parameters, our therapeutic approach is that mild LLI (less than 2.0 cm) has to be corrected using shoe elevation, in order to equalize the pelvic obliquity and, consequently, the spinal posture parameters.

Standard reference values of the upper body posture in healthy young female adults in Germany: an observational study

OBJECTIVE

Classifications of posture deviations are only possible compared with standard values. However, standard values have been published for healthy male adults but not for female adults.

DESIGN

Observational study.

SETTING

Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University Frankfurt/Main.

PARTICIPANTS

106healthy female volunteers (21-30 years old; 25.1±2.7 years) were included. Their body weight ranged from 46 to 106 kg (60.3±7.9 kg), the heights from 1.53 to 1.82 m (1.69±0.06 m) and the body mass index from 16.9 kg/m² to 37.6 kg/m² (21.1±2.6 kg/m²).

OUTCOME MEASURES

A three-dimensional back scan was performed to measure the upper back posture in habitual standing. The tolerance ranges and CI were calculated. Group differences were tested by the Wilcoxon Mann-Whitney U test.

RESULTS

In normal posture, the spinal column was marginally twisted to the left, and the vertebrae were marginally rotated to the right. The kyphosis angle is larger than the lumbar angle. Consequently, a more kyphotic posture is observed in the sagittal plane. The habitual posture is slightly scoliotic with a rotational component (scapular depression right, right scapula marginally more dorsally, high state of pelvic right, iliac right further rotated anteriorly).

CONCLUSIONS

Healthy young women have an almost ideally balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. Compared with young males, women show only marginal differences in the upper body posture. These values allow a comparison to other studies, both for control and patient data, and may serve as guideline in both clinical practice and scientific studies.

Does structural leg-length discrepancy affect postural control? Preliminary study

BACKGROUND

Leg-length inequality results in an altered position of the spine and pelvis. Previous studies on the influence of leg asymmetry on postural control have been inconclusive. The purpose of this paper was to investigate the effect of structural leg-length discrepancy (LLD) on the control of posture.

METHODS

We studied 38 individuals (19 patients with structural LLD, 19 healthy subjects). The examination included measurement of the length of the lower limbs and weight distribution as well as a static posturography. All statistical analyses were performed with Statistica software version 10.0. Non-parametrical Kruskal-Wallis with Dunn's post test and Spearman test were used. Differences between the groups and correlation between mean COP sway velocity and the value of LLD as well as the value of LLD and weight distribution were assumed as statistically significant at p < 0.05.

RESULTS

There was a significant difference in the asymmetry of weight distribution between the group of patients and the healthy subjects (p = 0.0005). Differences in a posturographic examination between the groups were not statistically significant (p > 0.05). Meaningful differences in mean COP velocity in mediolateral direction between tandem stance with eyes open and closed were detected in both groups (in controls p = 0.000134, in patients both with the shorter leg in a front and rear position, p = 0.029, p = 0.026 respectively). There was a positive moderate correlation between the value of LLD and the value of mean COP velocity in normal standing in mediolateral direction with eyes open (r = 0.47) and closed (r = 0.54) and in anterioposterior plane with eyes closed (r = 0.05).

CONCLUSIONS

The fact that there were no significant differences in posturography between the groups might indicate compensations to the altered posture and neuromuscular adaptations in patients with structural leg-length inequality. LLD causes an increased asymmetry of weight distribution. This study confirmed a fundamental role of the sight in postural control, especially in unstable conditions. The analysis of mean COP sway velocity may suggest a proportional deterioration of postural control with the increase of the value of leg-length asymmetry.

TRIAL REGISTRATION NUMBER

Trial registry: ClinicalTrials.gov NCT03048656 , 8 February 2017 (retrospectively registered).

Association between Sacral Slanting and Adjacent Structures in Patients with Adolescent Idiopathic Scoliosis

Background

Sacral slanting is a frequent unique phenomenon in patients with adolescent idiopathic scoliosis (AIS) and may be important for selecting the distal fusion level. However, the reason of the phenomenon remains unknown. The purpose of this study was to determine the association between sacral slanting and adjacent structures in patients with AIS.

Methods

A total of 303 AIS patients who underwent both whole spine standing anteroposterior (AP) and whole leg standing AP radiography were included. The degree of sacral slanting, pelvic obliquity, lumbar curve angles (L1-L4), and L4 tilt were assessed on whole spine standing AP radiographs. Whole leg standing AP radiographs were used to assess the degree of leg length discrepancy (LLD). Demographic data and radiological parameters were analyzed descriptively. Pearson correlation analysis and partial correlation analysis of the parameters were performed. A p-value of less than 0.05 was considered statistically significant.

Results

The proportion of patients with ≥ 5° of sacral slanting among those with < 3° of pelvic obliquity was 8.9% (27/303). Thirty-two patients (10.6%, 32/303) showed more than 10 mm of LLD. Sacral slanting was positively correlated with pelvic obliquity and lumbar curve (r = 0.445 and r = 0.325, respectively). Pelvic obliquity was also correlated with LLD and L4 tilt (r = 0.123 and r = 0.311, respectively). However, partial correlation analysis showed that LLD was not directly correlated with sacral slanting (r = −0.034).

Conclusions

Sacral slanting can be thought to be a compensatory mechanism for large lumbar curves, which is accompanied by pelvic obliquity. In contrast, a congenitally slanted upper sacrum may contribute to scoliosis in some cases. LLD was not directly correlated with sacral slanting.

Rasterstereographic measurement of scoliotic deformity

BACKGROUND

Back surface topography has gained acceptance in recent decades. At the same time, the motivation to use this technique has increased. From the view of the patient, the cosmetic aspect has played and still plays a major role as it provides a comprehensive documentation of cosmetic impairment. From the view of the medical practitioner, the aspect of reducing X-ray exposures in diagnosis and follow-up has been dominant and still prevails. Meanwhile, new aspects have emerged: due to the consequent three-dimensional view of the scoliotic condition, treatment success can be visualized convincingly. Clinical diagnosis is supported by information otherwise not supplied by X-rays, such as when functional examinations and diagnostic tests are recorded.

METHODS

Like rasterstereography, most techniques of actual back surface measurement refer to photogrammetry and the triangulation method. However, with respect to the particular clinical application, a wide spectrum of implementations exists. Applications in a clinic require high accuracy of measurement in a short time and comprehensive analysis providing data to be used to supplement and compare with radiographic data. This is exemplified by rasterstereography; the procedures of surface analysis and localization of landmarks using curvatures and the reconstruction of the spinal midline will be described.

ORTHOPAEDIC RELEVANCE

Based on rasterstereographic analysis, different geometrical measures that characterize the back surface are given and underlying skeletal structures described. Furthermore, in analogy to radiological projection, a 3-D reconstruction of the spinal midline is visualized by a frontal and lateral projection, allowing comparison with pertinent X-rays.

CONCLUSIONS

Surface topography and, in particular, rasterstereography provide reliable and consistent results that may be used to reduce X-ray exposure. Unfortunately, the correlation of shape parameters with the radiological Cobb angle is poor. However, the wealth of additional applications substantially enhances the spectrum of clinical value.

Does age affect the response of pelvis and spine to simulated leg length discrepancies? A rasterstereographic pilot study

PURPOSE

The purpose of this study was to investigate age differences in the response of the spine and pelvis to simulated leg length inequalities (LLIs).

METHODS

A total of 107 subjects, separated into three age groups (group 1: 20-39 years, group 2: 40-59 years, group 3: >60 years), were used to evaluate for any age effects in the response to LLIs. LLIs of +10, +20, and +30 mm were simulated with a simulation platform on both sides, and the respective changes of pelvic position (pelvic obliquity, pelvic torsion) and spinal posture (lateral deviation, surface rotation, kyphotic, and lordotic angles) were measured with a rasterstereographic system.

RESULTS

In all three age groups an increase in LLI led to significant changes in the pelvic position as measured by the parameters of pelvic obliquity and torsion. No significant differences in the response of the pelvis to the LLIs were found between the age groups. In all age groups an increase in surface rotation and lateral deviation of the spine with increasing LLIs was found. However, none of these parameters responded significantly different between the three age groups.

CONCLUSIONS

Under static conditions, LLIs lead to significant changes of the pelvic position and spinal posture. Despite all known age-related changes, no significant differences of the measured pelvic and spinal parameters in elderly patients as a response to the simulated LLIs occurred.