Persons with lower-limb amputation have impaired trunk postural control while maintaining seated balance

Lumbopelvic movement coordination during walking improves with transfemoral bone anchored limbs: Implications for low back pain

BACKGROUND

Low back pain (LBP) is more prevalent in patients with transfemoral amputation using socket prostheses than able-bodied individuals, in part due to altered spinal loading caused by aberrant lumbopelvic movement patterns. Early evidence surrounding bone-anchored limb functional outcomes is promising, yet it remains unknown if this novel prosthesis influences LBP or movement patterns known to increase its risk.

RESEARCH QUESTION

How are self-reported measures of LBP and lumbopelvic movement coordination patterns altered when using a unilateral transfemoral bone-anchored limb compared to a socket prosthesis?

METHODS

Fourteen patients with unilateral transfemoral amputation scheduled to undergo intramedullary hardware implantation for bone-anchored limbs due to failed socket use were enrolled in this longitudinal observational cohort study (7 F/7 M, Age: 50.2±12.0 years). The modified Oswestry Disability Index (mODI) (self-reported questionnaire) and whole-body motion capture during overground walking were collected before (with socket prosthesis) and 12-months following bone-anchored limb implantation. Lumbopelvic total range of motion (ROM) and continuous relative phase (CRP) segment angles were calculated during 10 bilateral gait cycles. mODI, total ROM, CRP and CRP variabilities were compared between time points.

RESULTS

mODI scores were significantly reduced 12-months after intramedullary hardware implantation for the bone-anchored limb (P = 0.013). Sagittal plane trunk and pelvis total ROM during gait were reduced after implantation (P = 0.001 and P < 0.001, respectively). CRP values were increased (more anti-phase) in the sagittal plane during single limb stance and reduced (more in-phase) in the transverse plane during pre-swing of the amputated limb gait cycle (P << 0.001 and P = 0.029, respectively). No differences in CRP values were found in the frontal plane.

SIGNIFICANCE

Decreases in mODI scores and lumbopelvic ROM, paired with the changes in lumbopelvic coordination, indicate that bone-anchored limbs may reduce LBP symptoms and reduce compensatory movement patterns for people with unilateral transfemoral amputation.

Trunk postural control during unstable sitting among individuals with and without low back pain: A systematic review with an individual participant data meta-analysis

INTRODUCTION

Sitting on an unstable surface is a common paradigm to investigate trunk postural control among individuals with low back pain (LBP), by minimizing the influence lower extremities on balance control. Outcomes of many small studies are inconsistent (e.g., some find differences between groups while others do not), potentially due to confounding factors such as age, sex, body mass index [BMI], or clinical presentations. We conducted a systematic review with an individual participant data (IPD) meta-analysis to investigate whether trunk postural control differs between those with and without LBP, and whether the difference between groups is impacted by vision and potential confounding factors.

METHODS

We completed this review according to PRISMA-IPD guidelines. The literature was screened (up to 7th September 2023) from five electronic databases: MEDLINE, CINAHL, Embase, Scopus, and Web of Science Core Collection. Outcome measures were extracted that describe unstable seat movements, specifically centre of pressure or seat angle. Our main analyses included: 1) a two-stage IPD meta-analysis to assess the difference between groups and their interaction with age, sex, BMI, and vision on trunk postural control; 2) and a two-stage IPD meta-regression to determine the effects of LBP clinical features (pain intensity, disability, pain catastrophizing, and fear-avoidance beliefs) on trunk postural control.

RESULTS

Forty studies (1,821 participants) were included for the descriptive analysis and 24 studies (1,050 participants) were included for the IPD analysis. IPD meta-analyses revealed three main findings: (a) trunk postural control was worse (higher root mean square displacement [RMSdispl], range, and long-term diffusion; lower mean power frequency) among individuals with than without LBP; (b) trunk postural control deteriorated more (higher RMSdispl, short- and long-term diffusion) among individuals with than without LBP when vision was removed; and (c) older age and higher BMI had greater adverse impacts on trunk postural control (higher short-term diffusion; longer time and distance coordinates of the critical point) among individuals with than without LBP. IPD meta-regressions indicated no associations between the limited LBP clinical features that could be considered and trunk postural control.

CONCLUSION

Trunk postural control appears to be inferior among individuals with LBP, which was indicated by increased seat movements and some evidence of trunk stiffening. These findings are likely explained by delayed or less accurate corrective responses.

SYSTEMATIC REVIEW REGISTRATION

This review has been registered in PROSPERO (registration number: CRD42021124658).

George L, Nankervis K, Sinclair J, Penhorwood G, Williams J, Clayton HM. Towards an Evidence-Based Classification System for Para Dressage: Associations between Impairment and Performance Measures

This study follows a previously defined framework to investigate the impact of impairment on performance in Para dressage athletes. Twenty-one elite Para dressage athletes (grades I to V) and eleven non-disabled dressage athletes (competing at Prix St. Georges or Grand Prix) participated. Data were collected in two phases: performing a two minute custom dressage test on a riding simulator while kinematic data were synchronously collected using inertial measurement units (2000 Hz) and optical motion capture (100 Hz), and clinically assessed using a battery of impairment assessment tools administered by qualified therapists. Impairment and performance measures were compared between Para and non-disabled athletes. Significant differences between athlete groups were found for all impairment measures and two performance measures: simulator trunk harmonics (p = 0.027) and athlete trunk dynamic symmetry (p < 0.001). Impairment assessments of sitting function and muscle tone could predict 19 to 35% of the impact of impairment on performance in Para athletes but not in non-disabled athletes. These findings provide the basis for a robust, scientific evidence base, which can be used to aid in the refinement of the current classification system for Para dressage, to ensure that it is in line with the International Paralympic Committee's mandate for evidence-based systems of classification.

Exercise Therapy in Nonspecific Low Back Pain among Individuals with Lower-Limb Amputation: A Systematic Review

Low back pain is very common condition that often becomes a long-lasting problem in prostheses users after lower limb amputation. The presented study aims to decide the potential benefits of exercise therapy on low back pain among lower limb amputees by using a systematic review. The PICO technique was used to answer the primary issue of this review: Does exercise treatment lessen the prevalence of low back pain in the population of lower limb amputees? Systematic review was conducted in the following databases: Medline-PubMed, EMBASE, Scopus, and Web of Science. Studies up to September 2010 published in English are included. Aim, target population, development and execution strategies, and treatment suggestions were among the data gathered. The primary outcomes of interest were exercise interventions as a therapy for low back pain but only two articles met including criteria. The search was broadened and 21 studies describing biomechanical changes in gait and pelvic-spine posture were analysed. This review indicates that movement therapy is a potential treatment strategy in low back pain among amputees. The major limitation of the study is the very heterogenous group of subjects in terms of amputation level, baseline activity level and comorbidities. We used a procedure that was registered in PROSPERO (CRD42022345556) to perform this systematic review of systematic reviews. There is a necessity of good quality research for concluding a consensus of exercise intervention.

Comparison of clinical and biomechanical characteristics between individuals with lower limb amputation with and without lower back pain: A systematic review and meta-analysis

BACKGROUND

Lower back pain is a debilitating condition common to individuals with lower limb amputation. It is unclear what risk factors contribute to the development of back pain. This study systematically reviewed and analyzed the available evidence regarding the clinical and biomechanical differences between individuals with amputation, with and without lower back pain.

METHODS

A literature search was conducted in PubMed, Web of Science, Scopus, and CINAHL databases in November 2020 and repeated in June 2021 and June 2022. Studies were included if they reported comparisons of demographic, anthropometric, biomechanical, and other clinical variables between participants with and without LBP. Study quality and potential for reporting bias were assessed. Meta-analyses were conducted to compare the two groups.

FINDINGS

Thirteen studies were included, with aggregated data from 436 participants (239 with LBP; 197 pain free). The median reporting quality score was 37.5%. The included studies enrolled participants who were predominantly male (mean = 91.4%, range = 77.8-100%) and with trauma-related amputation. Meta-analyses showed that individuals with LBP exhibited moderate (3.4 out of 10) but significantly greater pain than those without LBP. We found no between-group differences in age, height, weight, BMI, and time since amputation (p = 0.121-0.682). No significant differences in trunk/pelvic kinematics during gait were detected (p = 0.07-0.446) between the groups.

INTERPRETATION

Demographic, anthropometric, biomechanical, and simple clinical outcome variables may be insufficient for differentiating the risk of developing back pain after amputation. Investigators should be aware of the existing gender bias in sampling and methodological limitations, as well as to consider incorporating psychosocial measures when studying LBP in this clinical population.

A single-subject comparison of functional outcomes between lower limb salvage vs. transtibial amputation through sequential participation in a fall-prevention program

PURPOSE

Prior research has noted similar functional and subjective outcomes between individuals with delayed amputation vs. limb salvage; however, these reports are generally retrospective in nature. Here, we prospectively compare functional and subjective outcomes from an individual with limb salvage to a delayed transtibial amputation using a single-subject design with sequential participation in a fall-prevention program.

MATERIALS AND METHODS

The subject participated in a fall-prevention rehabilitation training program, once before undergoing a delayed transtibial amputation and again after. As part of the fall-prevention program, the participant completed pretraining and post-training assessments which quantified trunk control by 1) trunk flexion and flexion velocity after trip-inducing perturbations on a treadmill and 2) trunk sway parameters during unstable sitting. In addition, the four square step test was administered, and patient-reported outcomes, including pain, prosthetic/orthotic comfort, and walking/running endurance, were collected.

RESULTS

In general, the participant demonstrated improved trunk control after amputation, as evidenced by decreases in trunk flexion and flexion velocity after perturbation and sway parameters during unstable sitting. In addition, four square step test times were shorter with amputation vs. limb salvage; the participant also reported reduced pain and greater comfort with amputation (vs. limb salvage).

CONCLUSIONS

Although just a single participant, within-subject comparisons provide quantitative evidence that, for some individuals, delayed/late (transtibial) amputation after prolonged limb salvage may be beneficial in reducing pain and restoring function.

Immediate effect of stair exercise on stiffness, tone, and pressure pain threshold of thoracolumbar fascia in individuals with lower limb amputation: a preliminary report

BACKGROUND

Adaptations to the use of prosthesis in individuals with a lower limb amputation may cause changes in lumbopelvic region structures during daily life activities.

OBJECTIVE

To investigate the effect of stair exercise on the stiffness, tone, and pressure pain threshold (PPT) of the thoracolumbar fascia (TLF) in individuals with unilateral lower limb amputation.

DESIGN

This is a prospective preliminary study.

METHODS

The study was conducted in Prosthetic Orthotic Centers in Istanbul. Syrian individuals with unilateral transtibial (n = 17) and transfemoral (n = 15) amputation who received prosthesis and rehabilitation services at the centers between February 2020 and December 2020 were included in the study. The subjects were instructed to ascend and descend a nine-step stair one at a time at their maximum possible speed. Measurements were made before and immediately after the stair exercise. Tone and stiffness of TLF was measured using myometer. PPT was measured using algometer. Low back pain was evaluated using numerical pain rating scale.

RESULTS

In the transfemoral amputation group, PPT measurements taken immediately after stair exercise were significantly decreased in both the amputated ( P = 0.001) and intact ( P = 0.021) sides, whereas significant reduction in stiffness when compared with the prestair levels was observed only at the intact side ( P = 0.019). The change in PPT values on the amputated side was significantly higher in individuals with transfemoral amputation than those in individuals with transtibial amputation ( P = 0.011).

CONCLUSION

The decrease in PPT values of TLF in the transfemoral amputation group was considered as a precursor sign for low back pain development. Thus, exercises and preventive rehabilitation programs targeting TLF may be needed, especially in this group.

Musculoskeletal pain as the effect of internal compensatory mechanisms on structural and functional changes in body build and posture in elite Polish sitting volleyball players

Background

With the dynamic development of professional Paralympic sport, the prevalence of musculoskeletal pain and structural and/or functional disturbances in Para athletes constantly increases. The aim of the study was to evaluate the impact of internal compensatory mechanisms on selected aspects of body structure and function in elite sitting volleyball players.

Methods

The study included eighteen elite sitting volleyball players (male; n = 12, female; n = 6, age; 36.0 ± 6.1, body mass; 76.6 ± 16.1, body height; 179.3 ± 0.1) from the Polish national team. Retrospective and direct participatory observation methods were used in the study. NMQ-7 was used to assess the current prevalence and location of musculoskeletal pain. The evaluation of spinal curvature and pelvic inclination was performed using a non-invasive Medi Mouse method (Idiag M360) in three different trunk positions. All statistical analyses were performed using Statistica 13.3 software package.

Results

Lumbar hypolordosis was a predominant sagittal deviation of spinal curvature (n = 15;83%). Low back pain (LBP) and neck pain were the most frequent complaints (50%). Statistically significant differences in the values of thoracic kyphosis angle, pelvic inclination, and spine length (SL) in sagittal standing flexion and extension were found. However, there was no statistically significant difference in sagittal standing flexion for the lumbar lordosis angle with a simultaneous significant change in pelvic inclination (66.9°). Moreover, a tendency to interpenetration of relationships between variables that characterize (a) body structure and (b) function of the spine and musculoskeletal pain were observed. Shoulder pain correlated with SL (R = 0.6; p < 0.05) and body height (R = 0.5; p < 0.05). Pelvic inclination correlated with shoulder pain, LBP (R = 0.5; p < 0.05/R = 0.6; p < 0.01), and body trunk fat mass (R = − 0.6; p < 0.05).

Conclusions

Trunk fat mass induces internal compensatory mechanisms to maintain optimal pelvic inclination and sagittal spinal balance. Furthermore, the level of pelvic mobility may determine musculoskeletal pain in Para athletes with lower limb impairment.

The Impact of Internal Compensatory Mechanisms on Musculoskeletal Pain in Elite Polish Sitting Volleyball Players – A Preliminary Study

The purpose of the study was to evaluate the impact of (1) maximal muscular strength of the upper body and (2) fat mass on musculoskeletal pain and sagittal spinal curvature deviations in elite Polish sitting volleyball players. The study examined twelve players (age = 35.4 ± 6.9 years). The assessments were performed based on objective (anthropometric examinations, Medi Mouse, 1RM test) and subjective (NMQ = 7) measurements. All statistical analyses were performed using the SPSS. The lower back, the upper back and the neck were the most frequent painful areas. Statistical analyses showed a significant relationship between lumbar lordosis (LL) sagittal standing extension (r = 0.62; p = 0.03) and thoracic kyphosis (TK) sagittal standing flexion (r = -0.63; p = 0.28) with the 1RM. Furthermore, correlations between a body adiposity index and TK sagittal standing flexion and extension (r = -0.65; p = 0.05, r = - 0.58; p = 0.0.05) as well as LL sagittal standing flexion (r = 0.61; p = 0.05) were found. The body mass index correlated with wrist pain, whereas a very high relationship was found between pain in the wrists and knee joints. Neck pain positively correlated with TK and LL sagittal standing. Low back pain correlated with LL sagittal standing flexion and TK sagittal standing extension. Fat mass impacts the depth of anteroposterior spinal curvatures, what may cause pain in the neck and the lower back. The 1 RM bench press may influence the prevalence and location of musculoskeletal pain, whereas its values might be predicted by the depth of TK. A lower 1RM in the bench press may impact sagittal spinal curvature deviations. Deepen TK and LL significantly contribute to the prevalence of the neck pain.

Lumbopelvic coordination while walking in service members with unilateral lower limb loss: Comparing variabilities derived from vector coding and continuous relative phase

BACKGROUND

Continuous relative phase and vector coding are two common approaches for quantifying lumbopelvic coordination and variability. Evaluating the application of such methodologies to the lower limb loss population is important for better understanding reported asymmetrical movement dynamics of the lumbopelvic region.

RESEARCH QUESTION

How do coordination variabilities derived from trunk-pelvic coupling angles and continuous relative phases compare among individuals with and without unilateral lower limb loss walking at self-selected speeds?

METHODS

Full-body kinematics were obtained from thirty-eight males with unilateral lower limb loss (23 transtibial and 15 transfemoral) and fifteen males without limb loss while walking along a 15 m walkway. Coordination variabilities were derived from trunk-pelvic coupling angles and continuous relative phases and compared using a multivariate approach, as well as in unilateral outcome measures between control participants and participants with lower limb loss.

RESULTS

Overall, tri-planar measures of continuous relative phase variability were 19-43% larger compared to coupling angle variabilities for individuals without limb loss and individuals with transtibial limb loss. Individuals with transfemoral limb loss had 27% and 31% larger sagittal and transverse variabilities from continuous relative phases compared to coupling angles, respectively. During both prosthetic and intact limb stance, individuals with transtibial limb loss had 19-35% greater tri-planar measures of continuous relative phase variability compared to coupling angle variabilities. During intact stance phase, tri-planar measures of continuous relative phase variability were 27%- 42% larger compared to coupling angle variabilities for individuals without limb loss.

SIGNIFICANCE

While both methods provide valid estimates of lumbopelvic movement variability during gait, continuous relative phase variability may provide a more sensitive estimate in the lower limb loss population capturing velocity-specific motions of the trunk and pelvis.

Assessments of trunk postural control within a fall-prevention training program for service members with lower limb trauma and loss

BACKGROUND

Trunk postural control (TPC) is critical in maintaining balance following perturbations (i.e., avoiding falls), and impaired among persons with lower extremity trauma, contributing to elevated fall risk. Previously, a fall-prevention program improved TPC in individuals with unilateral transtibial amputation following trip-inducing perturbations. However, it is presently unclear if these improvements are task specific.

RESEARCH QUESTION

Do improvements to TPC gained from a fall-prevention program translate to another task which assesses TPC in isolation (i.e., unstable sitting)? Secondarily, can isolated TPC be used to identify who would benefit most from the fall-prevention program?

METHODS

Twenty-five individuals (21 male/4 female) with lower extremity trauma, who participated in a larger fall-prevention program, were included in this analysis. Trunk flexion and flexion velocity quantified TPC following perturbation; accelerometer-based sway parameters quantified TPC during unstable sitting. A generalized linear mixed-effects model assessed training-induced differences in TPC after perturbation; a generalized linear model assessed differences in sway parameters following training. Spearman's rho related training-induced changes to TPC following perturbation (i.e., the difference in TPC measures at pre- and post-training assessments) with pre- vs. post-training changes to sway parameters during unstable sitting (i.e., the difference in sway parameters at pre- and post-training assessments) as well as pre-training sway parameters with the pre- vs. post-training differences in TPC following perturbation.

RESULTS

Following training, trunk flexion angles decreased, indicating improved TPC; however, sway parameters did not differ pre- and post-training. In addition, pre- vs. post-training differences in TPC following perturbation were neither strongly nor significantly correlated with sway parameters. Moreover, pre-training sway parameters did not correlate with pre- vs. post-training differences in trunk flexion/flexion velocity.

SIGNIFICANCE

Overall, these results indicate that improvements to TPC gained from fall-prevention training are task-specific and do not translate to other activities. Moreover, isolated TPC measures are not able to identify individuals that benefit most from the fall-prevention program.

Femur Abduction Associated with Transfemoral Amputation Alters the Profile of Lumbopelvic Mechanical Loads During Generalized End-Limb Loading

Pain in the lower back is frequent problem for most individuals with transfemoral amputation, which limits their overall mobility and quality of life. While the underlying root causes of back pain are multifactorial, a contributing factor is the mechanical loading environment within the lumbopelvic joint. Specifically, this study aims to explore the upstream effects amputation has on the mechanical loading environment of the lumbopelvic joint using a 3D musculoskeletal model of transfemoral amputation. A generic musculoskeletal model was altered to represent a transfemoral amputation. Muscle parameters were adjusted to represent a myodesis amputation surgery that preserved musculotendon tension in a neutral anatomical pose. The model contained a total of 28 degrees of freedom and 76 muscles spanning the lower-limb and torso. In forward dynamics simulations, generalized external forces were applied to the distal end of the residual limb at a series of directions. Axial, oblique and transverse 10 N end-limb loads were applied. In addition, simulations were performed for 0°, 4°, and 8° of femur abduction, which are clinically observed in individuals with transfemoral amputation. In these simulations, reaction forces and moments at the lumbopelvic joint were computed. In general, femur abduction had little effect on back loading for an axial applied end-limb force. These data showed that while the individual magnitudes of lumbopelvic force and moment reactions did not significantly deviate for differing levels of femur abduction, the pattern of how these forces changes in response to different end-limb force directions (applied circumferentially along the limb) was affected by femur abduction angle.Clinical Relevance- The changes in joint reaction forces in the lumbopelvic joint from an aligned position to an abducted position reinforce the importance of avoiding hip flexion-abduction contracture during amputation surgery. This suggests that surgical techniques such as myodesis, osseointegration, or medial thighplasty, which intend to maintain anatomical alignment may have beneficial upstream effects for the patients during locomotion. Given the prevalence of lower back pain in individuals with transfemoral amputation, teasing out the causes of lower back pain could bring relief to a population that struggles with community independence.

Overall Greater Demands on the Musculoskeletal System at Multiple Walking Speeds in Service Members With Lower Limb Loss

Individuals with lower limb loss often walk with altered/asymmetric movement mechanics, postulated as a catalyst for development of low back and knee pain. Here, the authors simultaneously investigated trunk-pelvic movement patterns and lower limb joint kinematics and kinetics among 38 males with traumatic, unilateral lower limb loss (23 transtibial and 15 transfemoral), and 15 males without limb loss, at a self-selected and 2 standardized (1.0 and 1.6 m/s) speeds. Individuals with versus without lower limb loss walked with greater trunk range of motion in the frontal and transverse planes at all speeds (despite ∼10% slower self-selected speeds). At all speeds, individuals with versus without limb loss exhibited +29% larger medial ground reaction forces, and at 1.6 m/s also exhibited +50% to 110% larger vertical hip power generation, +27% to 80% larger vertical hip power absorption, and +21% to 90% larger medial-lateral hip power absorption. Moreover, pervasive biomechanical differences between transtibial versus transfemoral limb loss identify amputation-level movement strategies. Overall, greater demands on the musculoskeletal system across walking speeds, particularly at the hip, knee, and low back, highlight potential risk factors for the development/recurrence of prevalent secondary musculoskeletal conditions (eg, joint degeneration and pain) following limb loss.

Effect of Compensatory Mechanisms on Postural Disturbances and Musculoskeletal Pain in Elite Sitting Volleyball Players: Preparation of a Compensatory Intervention

The aim of the study was to identify the effect of compensatory mechanisms on the prevalence of sagittal spinal curvature deformity and musculoskeletal pain and to assess the interrelationships between those components in sitting volleyball players. Twenty-one elite Polish sitting volleyball players (age = 34.1 ± 7.5, BM = 77.9 ± 16.0) participated in the study in which direct participatory systematic observation and a non-invasive method were used. Both objective (anthropometric, spinal curvature-Idiag M360) and subjective (musculoskeletal ailments-NMQ = 7) measurements were performed. The Statistica 13.3 software package was used for statistical analyses. The neck, lower back (43%), and upper back (38%) were the most frequently reported painful areas. Of all participants, 76% reported sagittal spinal deformities. In the habitual position, the results indicated moderate correlations (r = 0.5, p < 0.05) between the lumbar concavity of the back and low back pain (LBP) and between thoracic convexity and LBP (r = 0.4, p < 0.05). Internal and external compensation have an effect on the prevalence of spinal curvature deformities in the sagittal plane, with thoracic hyperkyphosis (38%) and lumbar hyperlordosis (33%) being the most common. More severe lower and upper back pain were correlated with greater angles of thoracic kyphosis and lumbar lordosis in the habitual position.

Trunk Muscle Characteristics: Differences Between Sedentary Adults With and Without Unilateral Lower Limb Amputation

OBJECTIVE

The primary purpose of this study was to compare trunk muscle characteristics between adults with and without unilateral lower limb amputation (LLA) to determine the presence of modifiable trunk muscle deficits (ie, impaired activity, reduced volume, increased intramuscular fat) evaluated by ultrasonography (US) and magnetic resonance imaging (MRI). We hypothesized that compared with adults without LLA (controls), individuals with transfemoral or transtibial LLA would demonstrate reduced multifidi activity, worse multifidi and erector spinae morphology, and greater side-to-side trunk muscle asymmetries.

DESIGN

Cross-sectional imaging study.

SETTING

Research laboratory and imaging center.

PARTICIPANTS

Sedentary adults (n=38 total) with LLA (n=9 transfemoral level; n=14 transtibial level) and controls without LLA (n=15).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We examined bilateral multifidi activity using US at levels L3/L4-L5/S1. MRI was performed using 3-dimensional quantitative fat-water imaging; bilateral L1-L5 multifidi and erector spinae were manually traced, and muscle volume (normalized to body weight) and percentage intramuscular fat were determined. Between-group and side-to-side differences were evaluated.

RESULTS

Compared with adults without LLA, participants with LLA demonstrated reduced sound-side multifidi activity; those with transfemoral LLA had larger amputated-side multifidi volume, whereas those with transtibial LLA had greater sound- and amputated-side erector spinae intramuscular fat (P<.050). With transfemoral LLA, side-to-side differences in erector spinae volume, as well as multifidi and erector spinae intramuscular fat, were found (P<.050).

CONCLUSIONS

Impaired trunk muscle activity and increased intramuscular fat may be modifiable targets for intervention after LLA.

Trunk-pelvic coordination during unstable sitting with varying task demand: A methodological study

Unstable sitting is used commonly to evaluate trunk postural control (TPC), typically via measures based on center-of-pressure (CoP) time series. However, these measures do not directly reflect underlying control/movement strategies. We quantified trunk-pelvis coordination during unstable sitting using vector coding (VC) and correlated such coordination with CoP-based outcomes across varying task demands. Thirteen uninjured individuals (11 male/2 female) sat on an unstable chair at four instability levels, in a random order, defined relative to the individual gravitational gradient (∇G): 100, 75, 60, and 45%∇G. VC assessed trunk-pelvic coordination, and coupling angles classified movements as: 1) anti-phase, 2) in-phase, 3) trunk-phase, or 4) pelvic-phase. With decreasing %∇G (i.e., increasing instability), we found: increased anti-phase movement in the sagittal and frontal planes; decreased in-phase movement in the sagittal and frontal planes; and increased in-phase and pelvic-phase movement in the transverse plane. In the sagittal and frontal planes, we observed significant weak-to-moderate correlations between anti-phase and in-phase movements (0.288 < |ρ| < 0.549). Correlations between CoP-based measures and pelvic-phase and trunk-phase movements were typically weak and/or non-significant (|ρ| < 0.318). VC techniques discriminated between levels of instability during unstable sitting, identifying in-phase coordination (stiffening strategy) at lower instability levels and anti-phase coordination at higher instability levels. Compared to CoP-based measures, trunk coordination outcomes during unstable sitting provide measures of TPC that more directly quantify underlying movement strategies. These results can also serve as a baseline for future work investigating populations with impaired TPC (e.g., individuals with low back pain or limb loss).

Reducing Core Stability Influences Lower Extremity Biomechanics in Novice Runners

PURPOSE

The role of core stability in running and its influence on injury risk in runners is not well understood. The purpose of this study was to investigate the effect of core stability (and core fatigue) on running mechanics. We hypothesized that decreasing core stability in novice runners would result in altered running mechanics previously associated with increased risk for common lower extremity running injuries.

METHODS

Three-dimensional running kinematics and kinetics and seated postural sway on an unstable surface were collected on 25 healthy, novice runners before and after they performed a core stability knockdown protocol (CSKP), designed to temporarily reduce participants' core stability in a single testing session.

RESULTS

Linear mixed models demonstrated that the CSKP resulted in an increased peak knee flexion moment (0.51%BW·ht increase, effect size = 0.49, P = 0.021) and a decreased vertical average loading rate (4.5 BW·s decrease, effect size = 0.44, P = 0.037) during running, but no significant changes in peak knee adduction moment, knee adduction impulse, hip adduction moment, hip adduction impulse, or peak vertical ground reaction force (all P > 0.05). Of 25 runners, 20 demonstrated a measurable decrement in their core stability as defined by their seated postural sway center of pressure excursion changing more than the standard error of measurement of 76 mm.

CONCLUSIONS

An experimentally induced decrement in core stability in novice runners caused an increased peak knee flexion moment during stance, which has previously been associated with increased patellofemoral contact pressure during running. Therefore, these results demonstrate that insufficient core stability in novice runners may be a risk factor for developing patellofemoral pain. Other results did not support a role of core stability in other common overuse running injuries in this population.

Chronic low back pain influences trunk neuromuscular control during unstable sitting among persons with lower-limb loss

BACKGROUND

Persons with unilateral lower-limb loss are at increased risk for developing chronic low back pain. Aberrant trunk and pelvis motor behavior secondary to lower-limb loss potentially alters trunk postural control and increases demands on the trunk musculature for stability. However, it is unclear whether trunk postural control is associated with the presence or chronicity of low back pain within this population.

RESEARCH QUESTION

Is there a potential role of impaired trunk postural control among persons with lower limb loss and chronic low back pain?

METHODS

Two groups of males with unilateral lower-limb loss (n = 18 with chronic low back pain; n = 13 without pain) performed an unstable sitting task. Trunk postural control was characterized using traditional and non-linear measures derived from center-of-pressure time series, as well as trunk kinematics and the ratio of lumbar to thoracic erector spinae muscle activations.

RESULTS

Traditional and non-linear center-of-pressure measures and trunk muscle activation ratios were similar between groups, while participants with chronic low back pain demonstrated greater trunk motion and reduced local dynamic stability.

SIGNIFICANCE

Our results suggest that persons with both lower-limb loss and chronic low back pain exhibit impaired trunk postural control compared to those with limb loss but without pain. Aberrant trunk motor behavior may be a response to altered functional requirements of walking with a prosthesis. An inability to adequately control the trunk could lead to spinal instability and pain in the presence of repetitive exposure to aberrant motor behavior of these proximal structures during everyday activities.

Understanding Low Back Pain in Traumatic Lower Limb Amputees: A Systematic Review

Objective

This systematic review aims to evaluate current literature for the prevalence, causes, and effect of low back pain (LBP) in traumatic lower limb amputees, specifically its association with the kinematics and kinetics of the lumbar spine and lower extremities.

Data Sources

Databases (EMBASE, MEDLINE, Scopus, CINAHL, PsycINFO) were searched systematically for eligible studies from inception to January 2018.

Study Selection

The inclusion terms were synonyms of low back pain, lower limb amputation, and trauma, whereas studies involving nontraumatic amputee populations, single cases, or reviews were excluded. 1822 studies were initially identified, of which 44 progressed to full-text reading, and 11 studies were included in the review.

Data Extraction

Two independent reviewers reviewed the included studies, which were evaluated using a quality assessment tool and the Grades of Recommendation, Assessment, Development and Evaluation system for risk of bias, prior to analyzing results and conclusions.

Data Synthesis

There was an LBP prevalence of 52%-64% in traumatic amputees, compared to 48%-77% in the general amputee population (predominantly vascular, tumor, trauma), attributed to a mixture of biomechanical, psychosocial, and personal factors. These factors determined the presence, frequency, and severity of the pain in the amputees, significantly affecting their quality of life. However, little evidence was available on causality.

Conclusion

The high prevalence of LBP in traumatic amputees highlights the necessity to advance research into the underlying mechanics behind LBP, specifically the spinal kinematics and kinetics. This may facilitate improvements in rehabilitation, with the potential to improve quality of life in traumatic amputees.

Spinopelvic sagittal alignment of patients with transfemoral amputation

PURPOSE

This study aims to describe the spinopelvic sagittal alignment in transfemoral amputees (TFAs) from a radiologic study of the spine with a postural approach to better understand the high prevalence of low back pain (LBP) in this population.

METHODS

TFAs underwent X-rays with 3-D reconstructions of the full spine and pelvis. Sagittal parameters were analyzed and compared to the literature. Differences between TFAs with and without LBP were also observed.

RESULTS

Twelve subjects have been prospectively included (TFA-LBP group (n = 5) and TFA-NoP group (n = 7)). Four of the five subjects of the TFA-LBP group and two of the seven in TFAs-NoP group had an imbalanced sagittal posture, especially regarding the T9-tilt, significantly higher in the TFA-LBP group than in the TFA-NoP (p = 0.046). Eight subjects (6 TFA-NoP and 2 TFA-LBP) had abnormal low value of thoracic kyphosis (TK). Moreover, the mean angle of TK in the TFA-NoP group was lower than in the TFA-LBP group (p = 0.0511).

CONCLUSION

In the considered sample, TFAs often present a sagittal imbalance. A low TK angle seems to be associated with the absence of LBP. It can be hypothesized that this compensatory mechanism of the sagittal imbalance is the most accessible in this population. This study emphasizes the importance of considering the sagittal balance of the pelvis and the spine in patients with a TFA to better understand the high prevalence of LBP in this population. It should be completed by the analysis of the spinopelvic balance and the lower limbs in 3D. These slides can be retrieved under Electronic Supplementary Material.

Low back pain in persons with lower extremity amputation: a systematic review of the literature

BACKGROUND CONTEXT

Lower extremity amputation (LEA) is associated with an elevated risk for development and progression of secondary health conditions. Low back pain (LBP) is one such condition adversely affecting function, independence, and quality of life.

PURPOSE

The purpose of this study was to systematically review the literature to determine the strength of evidence relating the presence and severity of LBP secondary to LEA, thereby supporting the formulation of empirical evidence statements (EESs) to guide practice and future research.

STUDY DESIGN/SETTING

Systematic review of the literature.

METHODS

A systematic review of five databases was conducted followed by evaluation of evidence and synthesis of EESs.

RESULTS

Seventeen manuscripts were included. From these, eight EESs were synthesized within the following categories: epidemiology, amputation level, function, disability, leg length, posture, spinal kinematics, and osseointegrated prostheses. Only the EES on epidemiology was supported by evidence at the moderate confidence level given support by eight moderate quality studies. The four EESs for amputation level, leg length, posture, and spinal kinematics were supported by evidence at the low confidence level given that each of these statements had some evidence not supporting the statement but ultimately more evidence (and of higher quality) currently supporting the statement. The remaining three EESs that addressed function, disability and osseointegrated prosthetic use were all supported by single studies or had comparable evidence that disagreed with study findings rendering insufficient evidence to support the respective EES.

CONCLUSIONS

Based on the state of the current evidence, appropriate preventative and, particularly, treatment strategies to manage LBP in persons with LEA remain a knowledge gap and an area of future study.

Balance Perturbations as a Measurement Tool for Trunk Impairment in Cross-Country Sit Skiing

In cross-country sit-skiing, the trunk plays a crucial role in propulsion generation and balance maintenance. Trunk stability is evaluated by automatic responses to unpredictable perturbations; however, electromyography is challenging. The aim of this study was to identify a measure to group sit-skiers according to their ability to control the trunk. Seated in their competitive sit-ski, 10 male and 5 female Paralympic sit-skiers received 6 forward and 6 backward unpredictable perturbations in random order. k-means clustered trunk position at rest, delay to invert the trunk motion, and trunk range of motion significantly into 2 groups. In conclusion, unpredictable perturbations might quantify trunk impairment and may become an important tool in the development of an evidence-based classification system for cross-country sit-skiers.

Impact of Powered Knee-Ankle Prosthesis on Low Back Muscle Mechanics in Transfemoral Amputees: A Case Series

Regular use of prostheses is critical for individuals with lower limb amputations to achieve everyday mobility, maintain physical and physiological health, and achieve a better quality of life. Use of prostheses is influenced by numerous factors, with prosthetic design playing a critical role in facilitating mobility for an amputee. Thus, prostheses design can either promote biomechanically efficient or inefficient gait behavior. In addition to increased energy expenditure, inefficient gait behavior can expose prosthetic user to an increased risk of secondary musculoskeletal injuries and may eventually lead to rejection of the prosthesis. Consequently, researchers have utilized the technological advancements in various fields to improve prosthetic devices and customize them for user specific needs. One evolving technology is powered prosthetic components. Presently, an active area in lower limb prosthetic research is the design of novel controllers and components in order to enable the users of such powered devices to be able to reproduce gait biomechanics that are similar in behavior to a healthy limb. In this case series, we studied the impact of using a powered knee-ankle prostheses (PKA) on two transfemoral amputees who currently use advanced microprocessor controlled knee prostheses (MPK). We utilized outcomes pertaining to kinematics, kinetics, metabolics, and functional activities of daily living to compare the efficacy between the MPK and PKA devices. Our results suggests that the PKA allows the participants to walk with gait kinematics similar to normal gait patterns observed in a healthy limb. Additionally, it was observed that use of the PKA reduced the level of asymmetry in terms of mechanical loading and muscle activation, specifically in the low back spinae regions and lower extremity muscles. Further, the PKA allowed the participants to achieve a greater range of cadence than their predicate MPK, thus allowing them to safely ambulate in variable environments and dynamically control speed changes. Based on the results of this case series, it appears that there is considerable potential for powered prosthetic components to provide safe and efficient gait for individuals with above the knee amputation.

Impact of Traumatic Lower Extremity Injuries Beyond Acute Care: Movement-Based Considerations for Resultant Longer Term Secondary Health Conditions

Significance: Advances in field-based trauma care, surgical techniques, and protective equipment have collectively facilitated the survival of a historically large number of service members (SMs) following combat trauma, although many sustained significant composite tissue injuries to the extremities, including limb loss (LL) and limb salvage (LS). Beyond the acute surgical and rehabilitative efforts that focus primarily on wound care and restoring mobility, traumatic LL and LS are associated with several debilitating longer term secondary health conditions (e.g., low back pain [LBP], osteoarthritis [OA], and cardiovascular disease [CVD]) that can adversely impact physical function and quality of life. Recent Advances: Despite recent advancements in prosthetic and orthotic devices, altered movement and mechanical loading patterns have been identified among persons with LL and salvage, which are purported risk factors for the development of longer term secondary musculoskeletal conditions and may limit functional outcomes and/or concomitantly impact cardiovascular health. Critical Issues: The increased prevalence of and risk for LBP, OA, and CVD among the relatively young cohort of SMs with LL and LS significantly impact physiological and psychological well-being, particularly over the next several decades of their lives. Future Directions: Longitudinal studies are needed to characterize the onset, progression, and recurrence of health conditions secondary to LL and salvage. While not a focus of the current review, detailed characterization of physiological biomarkers throughout the rehabilitation process may provide additional insight into the current understanding of disease processes of the musculoskeletal and cardiovascular systems.

Nonlinear analysis of postural sway in subjects with below knee amputation during opened and closed eye conditions

OBJECTIVE

The aim of this study was to compare the structure of postural sway in healthy people and amputees with SACH foot (solid ankle cushion heel) and single axis foot during standing.

METHODS

Twenty healthy, 10 amputees with single axis foot, and 10 amputees with SACH foot participated in this study. The structure of postural sway of the subjects was evaluated using approximate entropy (ApEn).

RESULTS

People with SACH foot prosthesis exhibit increased regularity in postural sway compared to healthy people and people with single axis foot.

CONCLUSION

Amputees who used single axis prosthesis achieved appropriate adaptation to their prosthesis device.

Postural seated balance in children can be assessed with good reliability

BACKGROUND

Seated postural stability can be measured using Tekscan, CONFORMat. Standing postural stability has gained great clinical and, research value by use of different force platforms with mostly good reliability. No reliability testing or biologic variation assessment has been documented regarding seated balance. This study determines the reliability of the parameters of seated balance in healthy children using the Tekscan CONFORMat equipment.

METHODS

Sixty-six healthy children completed six measurements of seating position the first three with the child seated in a relaxed normal back position and the next three with the child seated in a complete up-right back position. The SAM software calculated five default parameters of balance (area, distance, variability, antero-posterior (AP) excursion and left-right excursion).

RESULTS

Reliability parameters were assessed by one-way analysis of variance intra-class correlation (ICC) proving excellent reliability for relaxed and up-right back position with respect to distance (0.75/0.84) and good reliability with respect to variability (0.61/0.62) and area (0.61/0.60). AP excursion (0.41/0.59) and left-right excursion (0.54/0.24) showed fair to poor reliability.

CONCLUSION

In conclusion, two of the five default parameters of balance used in the Tekscan CONFORMat system are direction-independent parameters and have been found reproducible for measuring seated balance in children. This study can be used as reference for comparisons of seated balance in children with affected seated postural control and for evaluating a clinical treatment effect.

Trunk-pelvis motion, joint loads, and muscle forces during walking with a transtibial amputation

People with unilateral, transtibial amputation (TTA) have an increased prevalence of chronic low back pain (LBP) relative to able-bodied people. However, a definitive cause of increased LBP susceptibility has not been determined. The purpose of this work was to compare dynamic trunk-pelvis biomechanics between people with (n=6) and without (n=6) unilateral TTA during walking using a computational modeling approach. A generic, muscle-actuated whole body model was scaled to each participant, and experimental walking data were used in a static optimization framework to calculate trunk-pelvis motion, L4L5 joint contact forces, and muscle forces within the trunk-pelvis region. Results included several significant between-group differences in trunk-pelvis biomechanics during different phases of the gait cycle. Most significant was greater lateral bending toward the residual side during residual single-limb stance (p<0.01), concurrent with an elevated L4L5 joint contact force (p=0.02) and greater muscle force from the intact-side obliques (p<0.01) in people with TTA relative to able-bodied people. During both double-limb support phases, people with TTA also had a greater range of axial trunk rotation away from the leading limb, concurrent with greater ranges of muscle forces in the erector spinae and obliques. In addition, a greater range of force (p=0.03) in residual-side psoas was found during early residual limb swing in people with TTA. Repeated exposure to atypical motion and joint/muscle loading in people with TTA may contribute to the development of secondary musculoskeletal disorders, including chronic, mechanical LBP.

The relationship between pelvis-trunk coordination and low back pain in individuals with transfemoral amputations

Low back pain (LBP) is common in individuals with transfemoral amputation and may result from altered gait mechanics associated with prosthetic use. Inter-segmental coordination, assessed through continuous relative phase (CRP), has been used to identify specific patterns as risk factors. The purpose of this study was to explore pelvis and trunk inter-segmental coordination across three walking speeds in individuals with transfemoral amputations with and without LBP. Nine individuals with transfemoral amputations with LBP and seven without pain were compared to twelve able-bodied subjects. Subjects underwent a gait analysis while walking at slow, moderate, and fast speeds. CRP and CRP variability were calculated from three-dimensional pelvis and trunk segment angles. A two-way ANOVA and post hoc tests assessed statistical significance. Individuals with transfemoral amputation demonstrated some coordination patterns that were different from able-bodied individuals, but consistent with previous reports on persons with LBP. The patient groups maintained transverse plane CRP consistent with able-bodied participants (p = 0.966), but not sagittal (p < 0.001) and frontal plane CRP (p = 0.001). Sagittal and frontal CRP may have been re-optimized based on new sets of constraints, such as protective rigidity of the segments, muscular strength limitations, or prosthesis limitations. Patients with amputations and without LBP exhibited few differences. Only frontal and transverse CRP shifted toward out-of-phase as speed increased in the patient group with LBP. Although a cause and effect relationship between CRP and future development of back pain has yet to be determined, these results add to the literature characterizing biomechanical parameters of back pain in high-risk populations.

Altered flexion-relaxation responses exist during asymmetric trunk flexion movements among persons with unilateral lower-limb amputation

Repetitive exposures to altered gait and movement following lower-limb amputation (LLA) have been suggested to contribute to observed alterations in passive tissue properties and neuromuscular control in/surrounding the lumbar spine. These alterations, in turn, may affect the synergy between passive and active tissues during trunk movements. Eight males with unilateral LLA and eight non-amputation controls completed quasi-static trunk flexion-extension movements in seven distinct conditions of rotation in the transverse plane: 0° (sagittally-symmetric), ±15°, ±30°, and ±45° (sagittally-asymmetric). Electromyographic (EMG) activity of the bilateral lumbar erector spinae and lumbar kinematics were simultaneously recorded. Peak lumbar flexion and EMG-off angles were determined, along with the difference ("DIFF") between these two angles and the magnitude of peak normalized EMG activities. Persons with unilateral LLA exhibited altered and asymmetric synergies between active and passive trunk tissues during both sagittally-symmetric and -asymmetric trunk flexion movements. Specifically, decreased and asymmetric passive contributions to trunk movements were compensated with increases in the magnitude and duration of active trunk muscle responses. Such alterations in trunk passive and active neuromuscular responses may result from repetitive exposures to abnormal gait and movement subsequent to LLA, and may increase the risk for LBP in this population.

Persons with unilateral lower-limb amputation have altered and asymmetric trunk mechanical and neuromuscular behaviors estimated using multidirectional trunk perturbations

Among persons with unilateral lower-limb amputation (LLA), proximal compensations and preferential use of the sound limb during gait and movement may lead to chronic alterations and/or asymmetries in trunk mechanical and neuromuscular behaviors. Trunk stiffness, the magnitude and timing of maximum reflex force, and EMG reflex delays of superficial trunk muscles, were estimated here using multidirectional (anteriorly- and laterally-directed) position-controlled horizontal trunk perturbations (±5mm, applied at T8) with the pelvis immobilized. Alterations and asymmetries in these trunk behaviors were quantified and compared among eight males with unilateral LLA, and eight male non-amputation controls. During anteriorly-directed perturbations, trunk stiffness and maximum reflex force were 24% and 23% lower, respectively, among participants with LLA compared to non-amputation controls, and the timing of maximum reflex force was 8% later. During lateral perturbations, trunk stiffness and maximum reflex force were also significantly lower among participants with LLA, by 22% and 27%, respectively. Bilateral asymmetries were present in trunk stiffness and the timing of maximum reflex force among persons with LLA. Specifically, trunk stiffness was 20% lower and timing of maximum reflex force was 9% later during perturbations involving spinal tissues and muscles ipsilateral to the side of amputation. Reduced and asymmetric trunk mechanical and neuromuscular behaviors may suggest a condition of reduced trunk stability among individuals with LLA, which could be due to repeated exposure to altered and asymmetric gait and movement and/or compensatory muscle recruitment in response to lost or altered musculature subsequent to LLA.