Effects of compression stockings on sympathetic activity and heart rate variability in individuals with spinal cord injury

Objective

To investigate whether wearing graduated compression stockings (GCS) could affect the sympatho-adrenergic and heart rate variability (HRV) responses at rest and after a strenuous wheelchair exercise in individuals with spinal cord injury (SCI).

Design

Crossover trial.

Setting

Department of Physical Medicine and Rehabilitation, Saint Etienne, France.

Participants

Nine men with SCI (five with low paraplegia: LP, four with high paraplegia: HP).

Interventions

Two maximal wheelchair exercise tests: with and without GCS (21 mmHg).

Main outcome measures

HRV measurements: high frequency (HF), low frequency (LF), and LF/HF ratio. Norepinephrine (NOR) and epinephrine (EPI), at rest and post-exercise. Secondary measures were: blood pressure, heart rate, maximal power output, oxygen uptake, stroke volume, cardiac output, at rest, during and after exercise.

Results

When wearing GCS: LFnu_wavelet-post significantly increased and HFnu_wavelet-post significantly decreased (P < 0.05) in SCI subjects, leading to an enhance ratio of LF_wavelet/HF_wavelet and a significantly increased in NOR_rest (P < 0.05).

Conclusions

GCS induces an enhanced sympathetic activity in individuals with paraplegia, regardless of the level of the injury. Enhanced post-exercise sympathetic activity with GCS may help prevent orthostatic hypotension or post-exercise hypotension.     

Mortality in patients with traumatic spinal cord injury: descriptive analysis of 62 deceased subjects

Study design

Retrospective study.

Objective

To investigate the causes of death in patients who were ≤50 years at the time of traumatic spinal cord injury (tSCI).

Setting

Convenience sample of a tertiary rehabilitation center.

Methods

All deceased patients with tSCI who survived a minimum of 10 years post-injury, were included. In addition, causes of death were compared between subjects surviving <10 years and ≥10 years. Neurological assessments were performed according to the American Spinal Injury Association scale. Data on causes of death were analyzed using the ICD-10 classifications. Differences were calculated using the Mann–Whitney and chi-square tests.

Results

A total of 100 patients, with 38 and 62 surviving <10 and ≥10 years, respectively, were included. No significant differences in causes of death were identified between these two groups. In patients surviving ≥10 years, paraplegia was associated with a higher life expectancy compared with tetraplegia, 34 and 25 years (p = 0.008), respectively, and the leading causes of death were septicemia (n = 14), ischemic heart disease (n = 10), neoplasms (n = 9), cerebrovascular diseases (n = 5), and other forms of heart diseases (n = 5). Septicemia, influenza/pneumonia, and suicide were the leading causes of death in tetraplegics, whereas ischemic heart disease, neoplasms, and septicemia were the leading causes of death in paraplegia.

Conclusion

Our monocentric study showed that in 62 deceased patients with SCI, the leading causes of death were septicemia, cardiovascular diseases, neoplasms, and cerebrovascular diseases. In addition, no significant differences were identified between causes of death among patients surviving <10 years and ≥10 years post-injury.     

Association of rs11190870 near LBX1 with adolescent idiopathic scoliosis susceptibility in a Han Chinese population

Purpose

To investigate whether rs11190870 near LBX1 correlates with the susceptibility or curve progression of adolescent idiopathic scoliosis (AIS) in a Han Chinese population.

Methods

A total of 949 AIS patients and 976 age-matched healthy controls were recruited. All the subjects were genotyped using the PCR-based invader assay. Case–control study and case-only study were performed to define the contribution of rs11190870 to predisposition and curve severity of AIS. Additionally, we further conducted a meta-analysis of the study findings together with those of previously reported studies.

Results

A significant association of rs11190870 with AIS was observed in the Han Chinese population (P = 1.8 × 10⁻⁹; odd ratio = 1.51; 95 % confidence interval = 1.33–1.71), and AIS patients with TT genotype had a larger Cobb angle than those with TC or CC genotype (P = 0.005). The meta-analysis confirmed that the positive association of this SNP with AIS in the East Asian population.

Conclusions

The SNP rs11190870 near LBX1 is associated with both susceptibility and curve progression of AIS.     

Genetic polymorphisms of interleukin-1 beta and osteosarcoma risk

Purpose

Osteosarcoma is the most common childhood bone cancer. Interleukin-1 beta (IL-1B) is crucially involved in osteosarcoma carcinogenesis. Whether genetic polymorphisms of IL-1B also influence osteosarcoma risk is unknown. The aim of this study was to investigate the association between IL-1B gene polymorphisms and osteosarcoma risk in Chinese Han patients.

Methods

A hospital-based case–control study involving 120 osteosarcoma patients and 120 controls was conducted. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect three IL-1B gene polymorphisms (−31 T/C, −511 C/T and +3954 C/T) in these patients.

Results

Patients with osteosarcoma had a significantly lower frequency of −31 CC genotype [odds ratio (OR) = 0.40, 95 % confidence interval (CI) = 0.17–0.92; P = 0.03] and −31 C allele (OR = 0.67, 95 % CI = 0.46–0.99; P = 0.04) than controls. Patients with osteosarcoma had a significantly lower frequency of −511 TT genotype (OR = 0.40, 95 % CI = 0.17–0.95; P = 0.04) than controls. The +3954 C/T gene polymorphisms were not associated with a risk of osteosarcoma. When stratified by Enneking stage, tumour location, histological type, tumour metastasis of osteosarcoma and family history of cancer, no statistically significant results were found.

Conclusions

This is the first study to provide evidence for an association of IL-1B gene polymorphisms with osteosarcoma risk.     

Prevalence of vitamin D insufficiency in Swiss teenagers with appendicular fractures: a prospective study of 100 cases

Background

The significance of subclinical vitamin D deficiency in the pathogenesis of fractures in children and adolescents currently remains unclear.

Objective

We aimed to determine the prevalence of vitamin D insufficiency and its effect on bone mineral density (BMD) and bone mineral content (BMC) values in a collective of Swiss Caucasian children with a first episode of appendicular fracture.

Design and methods

One hundred teenagers with a first episode of appendicular fracture [50 upper limb fractures (group 1) and 50 lower limb fractures (group 2)] and 50 healthy controls (group 3) were recruited into a cross-sectional study. The BMC and BMD values were measured by dual-energy X-ray absorptiometry, and serum 25 hydroxyvitamin D [25(OH)D] was assessed by electrochemiluminescence immunoassays.

Results

From the 100 injured teenagers in the study, 12 % had deficient vitamin D levels (<20 ng/mL; <50 nmol/L) and 36 % had insufficient levels (≥20 <30 ng/mL; ≥50 <78 nmol/L), whereas 6 and 34 % of healthy controls were, respectively, vitamin D deficient and insufficient. There were no significant differences for serum 25(OH)D levels, L2–L4 BMD Z-score, and L2–L4 BMC Z-score variables (p = 0.216) between the three groups nor for the calcaneal BMD Z-score variables (p = 0.278) between healthy controls and lower limb fracture victims. Investigations on the influences of serum 25(OH)D on BMD and BMC showed no correlation between serum 25(OH)D and L2–L4 BMD Z-scores (r = −0.15; p = 0.135), whereas low but significant inverse correlations were, surprisingly, detected between serum 25(OH)D and calcaneal BMD Z-scores (r = −0.21; p = 0.034) and between serum 25(OH)D and L2–L4 BMC Z-scores (r = −0.22; p = 0.029).

Conclusions

A significant proportion of Swiss Caucasian teenagers were vitamin D insufficient, independent of limb fracture status, in our study. However, this study failed to show an influence of low vitamin D status on BMD and/or BMC of the lumbar spine and heel.     

Muscle spasticity associated with reduced whole-leg perfusion in persons with spinal cord injury

Objective

To determine the association between peripheral blood flow and spasticity in individuals with spinal cord injury (SCI).

Design

A cross-sectional study with measurements of muscle spasticity and whole-limb blood flow in individuals with SCI.

Setting

University of Texas at Austin and Brain & Spine Recovery Center, Austin, TX, USA.

Participants

Eighteen individuals (14 males and 4 females) with SCI were classified into high (N = 7), low (N = 6), and no (N = 5) spasticity groups according to the spasticity levels determined by the modified Ashworth scale scores.

Interventions

Whole-limb blood flow was measured in the femoral and brachial arteries using Doppler ultrasound and was normalized to lean limb mass obtained with dual-energy X-ray absorptiometry.

Outcome measures

Limb blood flow and muscle spasticity.

Results

Age, time post-SCI, and the American Spinal Injury Association impairment scale motor and sensory scores were not different among groups with different muscle spasticity. Femoral artery blood flow normalized to lean leg mass was different (P = 0.001) across the three spasticity groups (high 78.9 ± 16.7, low 98.3 ± 39.8, no 142.5 ± 24.3 ml/minute/kg). Total leg muscle spasticity scores were significantly and negatively correlated with femoral artery blood flow (r = −0.59, P < 0.01). There was no significant difference in brachial artery blood flow among the groups.

Conclusions

Whole-leg blood flow was lower in individuals with greater spasticity scores. These results suggest that a reduction in lower-limb perfusion may play a role, at least in part, in the pathogenesis leading to muscle spasticity after SCI.     

Effect of choice of recovery patterns on handrim kinetics in manual wheelchair users with paraplegia and tetraplegia

Background

Impact forces experienced by the upper limb at the beginning of each wheelchair propulsion (WCP) cycle are among the highest forces experienced by wheelchair users.

Objective

To determine whether the magnitude of hand/forearm velocity prior to impact and effectiveness of rim impact force are dependent on the type of hand trajectory pattern chosen by the user during WCP. Avoiding patterns that inherently cause higher impact force and have lower effectiveness can be another step towards preserving upper limb function in wheelchair users.

Methods

Kinematic (50 Hz) and kinetic (2500 Hz) data were collected on 34 wheelchair users (16 with paraplegia and 18 with tetraplegia); all participants had motor complete spinal cord injuries ASIA A or B. The four-hand trajectory patterns were analyzed based on velocity prior to contact, peak impact force and the effectiveness of force at impact.

Results

A high correlation was found between the impact force and the relative velocity of the hand with respect to the wheel (P < 0.05). The wheelchair users with paraplegia were found to have higher effectiveness of force at impact as compared to the users with tetraplegia (P < 0.05). No significant differences in the impact force magnitudes were found between the four observed hand trajectory patterns.

Conclusion

The overall force effectiveness tended to be associated with the injury level of the user and was found to be independent of the hand trajectory patterns.     

Radiographic quantification of dynamic hip screw migration

Purpose

This study aimed to propose a technique to quantify dynamic hip screw (DHS®) migration on serial anteroposterior (AP) radiographs by accounting for femoral rotation and flexion.

Methods

Femoral rotation and flexion were estimated using radiographic projections of the DHS® plate thickness and length, respectively. The method accuracy was evaluated using a synthetic femur fixed with a DHS® and positioned at pre-defined rotation and flexion settings. Standardised measurements of DHS® migration were trigonometrically adjusted for femoral rotation and flexion, and compared with unadjusted estimates in 34 patients.

Results

The mean difference between the estimated and true femoral rotation and flexion values was 1.3° (95 % CI 0.9–1.7°) and −3.0° (95 % CI – 4.2° to −1.9°), respectively. Adjusted measurements of DHS® migration were significantly larger than unadjusted measurements (p = 0.045).

Conclusion

The presented method allows quantification of DHS® migration with adequate bias correction due to femoral rotation and flexion.

Electronic supplementary material

The online version of this article (doi:10.1007/s00264-013-2146-4) contains supplementary material, which is available to authorised users.     

The acromial index is not predictive for failed rotator cuff repair

Background

The main objective of this study was to evaluate the association between the acromial index (AI) and the incidence of recurrent tears of the rotator cuff (RC) in a cohort of patients with full thickness tears who underwent arthroscopic primary repair.

Methods

A prognostic study of a prospective case series of 103 patients with full thickness RC tears was undertaken. The average age was 59.5 years (39–74) and follow-up was 30.81 months (12–72). True anterior–posterior X-rays were obtained during the pre-operative evaluation. Pre and post-operative magnetic resonance imaging (MRI) were recorded.

Results

Eighteen cases with recurrent tears (17.4 %) were seen on post-operative MRI. The average AI for patients with recurrent tears was 0.711 ± 0.065 and for patients without recurrent tears 0.710 ± 0.064 (p < 0.05). A positive association between age and recurrent tears of the RC was noted (average ages: recurrent tears group 63 ± 5.9 years; group without recurrent tears 58.8 ± 7.5 years) (r = −0.216; p = 0.029). We did not find an association between size of the primary tear and recurrent tears (r = −0.075; p < 0.05) or between degrees of retraction of the primary and recurrent tears of the cuff (r = −0.073; p < 0.05). We observed that 38.9 % of the recurrent tears cases presented with more than one tendon affected before the arthroscopy. At follow-up, none of these recurrent tears showed more than one tendon affected on MRI evaluation.

Conclusion

In this study, we found that the AI radiological measurement is not a predictor for recurrent tears of the RC after primary arthroscopic repair.     

The deviation of the mechanical leg axis correlates with an increased hip alpha angle and could be a predictor of femoroacetabular impingement

Purpose

This study was designed to evaluate whether the mechanical axis deviation (MAD) of the leg correlates with an increased hip alpha angle as described by Nötzli, which is associated with femoroacetabular impingement (FAI).

Methods

In a retrospective analysis, standing full-length anteroposterior radiographs were analysed in patients who suffered from symptomatic leg alignment. The study included 85 radiographs of 80 patients with an average age of 43.11 years (range 18–60 years). Five patients underwent a bilateral long-leg X-ray examination. All radiographs were transferred as Digital Imaging and Communications in Medicine data files from the Picture Archiving and Communications System into the OrthoPlanner software version 2.3.2. The radiographs were measured by one orthopaedic surgeon and one independent radiologist.

Results

The mean value of the alpha angle of Nötzli was 61.43° (49.07–74.04°). A total of 57 (67 %) radiographs showed a varus deviation, 25 (29.5 %) had a valgus malalignment and three (3.5 %) a straight leg axis. Of 82 radiographs, 40 (48.8 %) had a moderate axis deviation with a MAD <15 or > − 15 mm and a mean alpha angle of 57.81°, and 42 (51.2 %) with extended axis deviation of a MAD > 15 or < − 15 mm had a mean alpha angle of 62.93°; 40 (95.2 %) of these 42 showed an alpha angle > 55°. The alpha angle was significantly increased in extended axis deviation compared to moderate axis deviation (P = 0.001).

Conclusions

This study confirmed that increased alpha angles were found significantly at higher degrees of axis deviation on the full-length radiograph. In cases of a MAD >15 or < − 15 mm and symptomatic coxalgia, diagnostic tests must be pursued for FAI.     

Effects of reduction in shoulder pain on quality of life and community activities among people living long-term with SCI paraplegia: a randomized control trial

Objective/background

People with spinal cord injury (SCI) paraplegia can develop shoulder problems over time, which may also cause pain. Shoulder pain may complicate or interfere with a person''s daily activities, social events, and their overall quality of life (QOL). The purpose of this study was to examine changes in social interaction and QOL after an exercise treatment for shoulder pain in people with SCI paraplegia.

Design

Fifty-eight participants with SCI paraplegia who were also experiencing shoulder pain were selected and randomized to either an exercise treatment or a control group. Participants in the treatment group participated in a 12-week, at-home, exercise and movement optimization program designed to strengthen shoulder muscles and modify movements related to upper extremity weight bearing.

Methods

Participants filled out self-report measures at baseline, 12 weeks later at the end of treatment, and at a 4-week follow-up.

Outcome measures

The Wheelchair User''s Shoulder Pain Index (WUSPI), the Social Interaction Inventory (SII), and the Subjective Quality of Life Scale.

Results

From the baseline to the end of treatment, repeated-measures analysis of variance revealed a significant interaction between WUSPI and SII scores, P < 0.001, and between WUSPI and QOL scores, P < 0.001.

Conclusion

Reductions in shoulder pain were related to significant increases in social participation and improvements in QOL. However, increases in social participation did not significantly affect improvements in QOL.     

The relevance of sacral and sacro-pelvic morphology in developmental lumbosacral spondylolisthesis: are they equally important?

Study design

Retrospective study of the importance of sacral and sacro-pelvic morphology in developmental L5–S1 spondylolisthesis.

Objectives

To determine and compare the importance of sacral and sacro-pelvic morphology in developmental L5–S1 spondylolisthesis.

Summary and background data

Recent studies have shown abnormalities in sacral and sacro-pelvic morphology in spondylolisthesis. However, it is still unclear if sacral and sacro-pelvic morphology are correlated and if they are equally important in the progression of spondylolisthesis.

Methods

Lateral radiographs of 120 controls and 131 subjects with developmental L5–S1 spondylolisthesis were analyzed. Sacral table angle (STA) and pelvic incidence (PI) were compared using Student t tests. The relationship between STA and PI was assessed separately in the control and spondylolisthesis groups using Pearson’s coefficients. The proportion of subjects with high PI but average STA was compared to the proportion of subjects with low STA but average PI using χ² tests.

Results

STA was significantly lower and PI was significantly higher in the spondylolisthesis group. STA was statistically related to PI in both control (r = −0.43) and spondylolisthesis (r = −0.57) groups. In the spondylolisthesis group, STA (r = −0.45) and PI (r = 0.35) were significantly related to slip percentage. STA remained statistically related to slip when controlling for PI. A significantly greater proportion of subjects in the spondylolisthesis group had average STA and high PI, rather than average PI and low STA.

Conclusion

The significant relationship between PI and STA validates that geometrically sacral morphology depends on sacro-pelvic morphology. This study failed to demonstrate a clear predominant role of either STA or PI in the presence of spondylolisthesis.     

A report of anticipated benefits of functional electrical stimulation after spinal cord injury

Background

Functional electrical stimulation (FES) has been regularly used to offset several negative body composition and metabolic adaptations following spinal cord injury (SCI). However, the outcomes of many FES trials appear to be controversial and incoherent.

Objective

To document the potential consequences of several factors (e.g. pain, spasms, stress and lack of dietary control) that may have attenuated the effects on body composition and metabolic profile despite participation in 21 weeks of FES training.

Participant

A 29-year-old man with T6 complete SCI participated in 21 weeks of FES, 4 days per week.

Methods

Prior to and following training, the participant performed arm-crank-graded exercise testing to measure peak VO₂. Tests conducted included anthropometrics and dual energy X-ray absorptiometry body composition assessments, resting energy expenditure, plasma lipid profiles and intravenous glucose tolerance tests.

Results

The participant frequently reported increasing pain, stress and poor eating habits. VO₂ peak decreased by 2.4 ml/kg/minute, body mass increased by 8.5 kg, and body mass index increased from 25 to 28 kg/m². Waist and abdominal circumferences increased by 2–4 cm, while %fat mass increased by 5.5%. Absolute increases in fat mass and fat-free mass of 8.4 and 1 kg, respectively, were reported. Fasting and peak plasma glucose increased by 12 and 14.5%, while lipid panel profiles were negatively impacted.

Conclusion

Failure to control for the listed negative emerging factors may obscure the expected body composition and metabolic profile adaptations anticipated from FES training.     

Underestimation of Bone Loss of the Spine With Posterior-Anterior Dual-Energy X-Ray Absorptiometry in Patients With Spinal Cord Injury

Background:

Bone mineral density (BMD) of the lumbar spine (L-spine) has been reported to be normal by routine posterior-anterior (PA) bone density imaging in patients with chronic spinal cord injury (SCI).

Objective:

To determine BMD of the L-spine by PA and lateral (LAT) dual-energy radiographic absorptiometry (DXA) in patients with chronic SCI.

Design:

Prospective study.

Setting:

Veterans Affairs Medical Center and a private rehabilitation facility.

Methods:

Measurements of the PA and LAT L-spine and hip were performed in 15 patients with SCI: 9 with tetraplegia and 6 with paraplegia. The DXA (GE Lunar Advance DXA) images were obtained using standard software. Results are reported as mean ± SD.

Results:

The mean age was 35 ± 15 years (range  =  20–62 years), and the duration of injury was 57 ± 74 months (range  =  3–240 months). T- and Z-scores were lower for the LAT L-spine than those for PA L-spine (T-scores L2: −0.7 ± 1.2 vs 0.0 ± 1.4, P < 0.01; L3: −0.9 ± 1.6 vs 0.3 ± 1.3, P < 0.002; L2-L3: −0.8 ± 1.3 vs 0.2 ± 1.3, P < 0.001; Z-scores L2: −0.3 ± 1.1 vs 0.2 ± 1.2, P < 0.05; L3: −0.6 ± 1.3 vs 0.5 ± 1.3, P < 0.01; L2-L3: −0.4 ± 1.1 vs 0.4 ± 1.2, P < 0.005). The T- and Z-scores for the total hip (−1.1 ± 1.0 and −1.0 ± 1.0, respectively) and L2-L3 LAT L-spine demonstrated remarkable similarity, whereas the L2-L3 PA L-spine scores were not reduced. Bone mineral density of the LAT L-spine, but not the PA L-spine, was significantly reduced with increasing duration of injury.

Conclusions:

Individuals with SCI may have bone loss of the L-spine that is evident on LAT DXA that may be misdiagnosed by PA DXA, underestimating the potential risk of fracture.     

Apoptosis of endplate chondrocytes in post-laminectomy cervical kyphotic deformity

Purpose

The present study was performed to establish an animal model of cervical kyphosis after laminectomy (C2–C5), and to determine the role of endplate chondrocytes apoptosis in cervical kyphosis after laminectomy.

Methods

Twenty-four 3-month-old sheep were randomly divided into two groups: the laminectomy group (n = 12), and the control group (n = 12). The cervical spine alignment was evaluated on a lateral cervical spine X-ray using Harrison’s posterior tangent method before surgery and at follow-up. Cartilaginous endplate chondrocyte apoptosis was confirmed using transmission electron microscopy and terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick-end labelling.

Results

The mean preoperative cervical curvature (C2–5) in the surgery group was −15.8°. The cervical curvature was 19.1° at 3 months post-operation and decreased to 20.2° at the final follow-up postoperatively. The cervical curvature was significantly decreased in the laminectomy group compared with the control group at the last follow-up (P < 0.001), which was a direct indication of kyphotic change. The incidence of apoptotic cells in the surgery group was significantly higher at the 3- and 6-month follow-up than the incidence in the control group.

Conclusions

The frequency of endplate chondrocyte apoptosis in the laminectomy group was significantly higher than in the control group, indicating that chondrocyte apoptosis may play a pivotal role in the progress of post-laminectomy cervical kyphosis.     

Sprengel’s shoulder treated by the Woodward procedure: analysis of factors affecting functional and cosmetic outcome

Purpose

To report the functional and cosmetic results of cases with Sprengel’s shoulder who underwent the Woodward procedure.

Materials and methods

Twelve children were operated at a mean age of 5.58 years and reviewed at an average follow up of 31.83 months.

Results

The mean preoperative Cavendish grade for cosmetic evaluation was 3.17, which decreased to 1.25 postoperatively (statistically significant, p < 0.0005, Wilcoxon signed-rank test). Similarly, the range of abduction at the shoulder increased from a mean of 115.83° preoperatively to 153.33° at final review (p < 0.0005). Age had a negative correlation with both functional improvement (r = −0.55, Spearman correlation coefficient) and cosmetic improvement (r = −0.11), although the latter suggested a very weak association, if any. Cavendish grade improvement and increase in abduction had a strong positive association (r = 0.713). However, there was no correlation between the increase in abduction and lowering of the scapula achieved (r = 0.131). The presence of an omovertebral bar did not affect the final functional outcome, nor did the presence of associated congenital anomalies.

Conclusion

The Woodward procedure is a reliable method for obtaining uniformly predictable results in Sprengel’s shoulder. The surgery should be performed at a younger age in order to optimise the functional outcome.     

What Are the Biomechanical Effects of Half-pin and Fine-wire Configurations on Fracture Site Movement in Circular Frames?

Background

Fine-wire circular frame (Ilizarov) fixators are hypothesized to generate favorable biomechanical conditions for fracture healing, allowing axial micromotion while limiting interfragmentary shear. Use of half-pins increases fixation options and may improve patient comfort by reducing muscle irritation, but they are thought to induce interfragmentary shear, converting beam-to-cantilever loading. Little evidence exists regarding the magnitude and type of strain in such constructs during weightbearing.

Questions/purposes

This biomechanical study was designed to investigate the levels of interfragmentary strain occurring during physiologic loading of an Ilizarov frame and the effect on this of substituting half-pins for fine-wires.

Methods

The “control” construct was comprised of a four-ring all fine-wire construct with plain wires at 90°-crossing angles in an entirely unstable acrylic pipe synthetic fracture model. Various configurations, substituting half-pins for wires, were tested under levels of axial compression, cantilever bending, and rotational torque simulating loading during gait. In total three frames were tested for each of five constructs, from all fine-wire to all half-pin.

Results

Substitution of half-pins for wires was associated with increased overall construct rigidity and reduced planar interfragmentary motion, most markedly between all-wire and all-pin frames (axial: 5.9 mm ± 0.7 vs 4.2 mm ± 0.1, mean difference, 1.7 mm, 95% CI, 0.8–2.6 mm, p < 0.001; torsional: 1.4% ± 0.1 vs 1.1% ± 0.0 rotational shear, mean difference, 0.3%, 95% CI, 0.1%–0.5%, p = 0.011; bending: 7.5° ± 0.1 vs 3.4° ± 0.1, mean difference, −4.1°, 95% CI, −4.4° to −3.8°, p < 0.001). Although greater transverse shear strain was observed during axial loading (0.4% ± 0.2 vs 1.9% ± 0.1, mean difference, 1.4%, 95% CI, 1.0%–1.9%, p < 0.001), this increase is unlikely to be of clinical relevance given the current body of evidence showing bone healing under shear strains of up to 25%. The greatest transverse shear was observed under bending loads in all fine-wire frames, approaching 30% (29% ± 1.9). This was reduced to 8% (±0.2) by incorporation of sagittal plane half-pins and 7% (±0.2) in all half-pin frames (mean difference, −13.2% and −14.0%, 95% CI, −16.6% to 9.7% and −17.5% to −10.6%, both p < 0.001).

Conclusions

Appropriate use of half-pins may reduce levels of shear strain on physiologic loading of circular frames without otherwise altering the fracture site mechanical environment at levels likely to be clinically important. Given the limitations of a biomechanical study using a symmetric and uniform synthetic bone model, further clinical studies are needed to confirm these conclusions in vivo.

Clinical Relevance

The findings of this study add to the overall understanding of the mechanics of circular frame fixation and, if replicated in the clinical setting, may be applied to the preoperative planning of frame treatment, particularly in unstable fractures or bone transport where control of shear strain is a priority.     

Kinetic magnetic resonance imaging analysis of lumbar segmental mobility in patients without significant spondylosis

Purpose

The purpose of this study was to examine lumbar segmental mobility using kinetic magnetic resonance imaging (MRI) in patients with minimal lumbar spondylosis.

Methods

Mid-sagittal images of patients who underwent weight-bearing, multi-position kinetic MRI for symptomatic low back pain or radiculopathy were reviewed. Only patients with a Pfirrmann grade of I or II, indicating minimal disc disease, in all lumbar discs from L1–2 to L5–S1 were included for further analysis. Translational and angular motion was measured at each motion segment.

Results

The mean translational motion of the lumbar spine at each level was 1.38 mm at L1–L2, 1.41 mm at L2–L3, 1.14 mm at L3–L4, 1.10 mm at L4–L5 and 1.01 mm at L5–S1. Translational motion at L1–L2 and L2–L3 was significantly greater than L3–4, L4–L5 and L5–S1 levels (P < 0.007). The mean angular motion at each level was 7.34° at L1–L2, 8.56° at L2–L3, 8.34° at L3–L4, 8.87° at L4–L5, and 5.87° at L5–S1. The L5–S1 segment had significantly less angular motion when compared to all other levels (P < 0.006). The mean percentage contribution of each level to the total angular mobility of the lumbar spine was highest at L2–L3 (22.45 %) and least at L5/S1 (14.71 %) (P < 0.001).

Conclusion

In the current study, we evaluated lumbar segmental mobility in patients without significant degenerative disc disease and found that translational motion was greatest in the proximal lumbar levels whereas angular motion was similar in the mid-lumbar levels but decreased at L1–L2 and L5–S1.     

Is tranexamic acid effective and safe in spinal surgery? A meta-analysis of randomized controlled trials

Purpose

The present meta-analysis aimed at assessing the effectiveness and safety of tranexamic acid (TXA) in reducing blood loss and transfusion in spinal surgery.

Methods

Systematic searches of all studies published through March 2012 were identified from PubMed, EMBase, Cochrane library, Science Direct, and other databases. Only randomized controlled trials (RCTs) were included in the present study. Two independent reviewers searched and assessed the literature. Mean difference (MD) of blood loss and blood transfusions, risk ratios (RR) of transfusion rate and of deep vein thrombosis rate in the TXA-treated group versus placebo group were pooled throughout the study. The meta-analysis was conducted by RevMan 5.1 software.

Results

Six placebo-controlled RCTs encompassing 411 patients met the inclusion criteria for our meta-analysis. The use of TXA significantly reduced both total blood loss [MD = −285.35, 95 % CI (−507.03 to −63.67), P = 0.01] as well as the number of patients requiring blood transfusion [RR = 0.71, 95 % CI (0.54–0.92), P = 0.01]. None of the patients in the treatment group had deep-vein thrombosis (DVT) or pulmonary embolism.

Conclusions

Intravenous use of TXA for patients undergoing spinal surgery is effective and safe. It reduces total blood loss and the need for blood transfusion, particularly in the using of high dosage of TXA (≥15 mg/kg), yet does not increase the risk of postoperative DVT. Due to the limitation of the quality of the evidence currently available, high-quality RCTs are required.     

Clinical outcome and changes in gait pattern after pilon fractures

Purpose

Axial burst fractures of the distal tibia are challenging to treat and often lead to restricted function of the lower limb. The purpose of this study was to investigate the clinical outcome and changes in gait pattern in such patients.

Methods

Thirty-five patients in a level 1 trauma centre were followed up clinically and by gait analysis. The American Orthopaedic Foot and Ankle Society (AOFAS), visual analogue scale (VAS) foot and ankle scale and Phillips scores were applied. Dynamic pedography (emed-M; Novel, Germany) with analyses of load, pressure and force-time integral were undertaken to investigate possible changes in gait pattern.

Results

Mean follow-up was 50 (19–100) months. Mean AOFAS, VAS foot and ankle and Phillips scores were 65, 63 and 55 points, respectively. There were clear correlations between fracture severity in the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification and functional outcome in AOFAS (−0.63; p < 0.01), VAS foot and ankle scale (−0.56; p < 0.01) and Phillips (−0.64; p < 0.01) scores. There was a high correlation of 0.74 (p < 0.01) between the severity of the injury in the AO-classification and onset of post-traumatic arthrosis. Dynamic pedography revealed lesser load bearing for the total foot, medial foot, heel, first metatarsal and medial forefoot for the affected limb, and increased load bearing was seen in the lateral midfoot region.

Conclusions

Fractures of the tibial pilon lead to restricted function of the lower limb. Clinical outcome correlates with fracture severity in the AO classification, the onset of post-traumatic arthrosis and changes in gait patterns.