Innominate movement patterns, rotation trends and range of motion in individuals with low back pain of sacroiliac joint origin

Biomechanical Effects of Multi-segment Fixation on Lumbar Spine and Sacroiliac Joints: A Finite Element Analysis

OBJECTIVE

Spine fixation surgery affects the biomechanical environment in the sacroiliac joint (SIJ), which may lead to the SIJ pain or degeneration after surgery. The purpose of this study is to determine the impact of the number and position of fixed segments on the SIJs and provide references for surgeons to plan fixation levels and enhance surgical outcomes.

METHODS

The intact lumbar-pelvis finite element (FE) models and 11 fixation FE models with different number and position of fixed segments were developed based on CT images. A 400N follower load and 10° range of motion (ROM) of the spine were applied to the superior endplate of L1 to simulate the flexion, extension, bending and torsion motion after surgery. The peak stress on the SIJs, lumbar intervertebral discs, screws and rods were calculated to evaluate the biomechanical effects of fixation procedures.

RESULTS

With the lowermost instrumented vertebra (LIV) of L5 or S1, the peak stress on SIJs increased with the number of fixed segments increasing. The flexion motion led to the greater von Mises stress on SIJ compared with other load conditions. Compared with the intact model, peak stress on all fixed intervertebral discs was reduced in the models with less than three fixed segments, and it increased in the models with more than three fixed segments. The stress on the SIJ was extremely high in the models with all segments from L1 to L5 fixed, including L1-L5, L1-S1 and L1-S2 fixation models. The stress on the segment adjacent to the fixed segments was significant higher compared to that in the intact model. The peak stress on rods and screws also increased with the number of fixed segments increasing in the flexion, extension and bending motion, and the bending and flexion motions led to the greater von Mises stress on SIJs.

CONCLUSION

Short-term fixation (≤2 segments) did not increase the stress on the SIJs significantly, while long-term segment fixation (≥4 segments) led to greater stress on the SIJs especially when all the L1-L5 segments were fixed. Unfixed lumbar segments compensated the ROM loss of the fixed segments, and the preservation of lumbar spine mobility would reduce the risks of SIJ degeneration.

Comparison of muscle energy technique and mobilization with movement to reduce pain and improve functional status in subjects with anterior innominate ilio-sacral dysfunction

OBJECTIVE

This study aimed to compare Muscle energy technique (METs) and Mobilization with movement (MWM) for pain reduction and improving functional status in subjects with anterior innominate iliosacral dysfunction.

METHODOLOGY

Thirty-six patients with anterior innominate iliosacral dysfunction were randomly assigned to both groups. Numeric Pain Rating Scale (NPRS) and Modified Oswestry Disability Index (MODI) were used to measure pain and functional disability. Four weeks of treatment sessions were given to each participant.

RESULTS

The findings of this study have revealed that statistically, differences were present within and between two groups (p-value <0.05) in the Numeric Pain Rating Score and Modified Oswestry Disability Index. After 4 weeks of treatment, pain intensity decreased and functional ability increased to a greater extent in the MET group, with a mean value of 3.05 ± 0.96 for pain and 23.82 ± 4.39 for modified Oswestry index as compared to the MWM group with a mean value of 4.58 ± 1.06 for pain and 30.29 ± 5.89 for modified Oswestry index in mobilization with movement group.

CONCLUSION

This study concluded that both Muscle Energy Technique and Mobilization with Movement techniques are effective in reducing pain and improving functional ability in patients with Anterior Innominate Iliosacral dysfunction. But when both groups were compared with each other Muscle Energy Techniques were more effective than Mobilization with Movement.

Sacroiliac pain after total hip arthroplasty: a combined analysis of clinical data and three-dimensional imaging in standing and sitting positions

PURPOSE

Patients frequently complain of low back pain and sacroiliac joint pain (SIP) following total hip arthroplasty (THA). We hypothesized that patients with SIP would display different pelvic incidence (PI) values between standing and relaxed sitting positions, indicative of increased motion in the sacroiliac joints.

METHODS

In this retrospective case-control study, 94 patients who underwent unilateral THA and experienced SIP were compared with 94 control patients without SIP. SIP was confirmed through clinical tests and investigated using biplanar imaging in both standing and sitting positions. The key parameters analyzed included PI, sacral slope (SS), lumbar lordosis (LL), and limb length discrepancy (LLD).

RESULTS

Patients without SIP showed a mean difference in PI of -1.5° (-8°-5°) between standing-to-sitting positions, whereas those with SIP showed a difference of -3.3° (-12°-0°)(P < 0.0001), indicating more motion in the sacroiliac joint during daily activities in the latter group. Patients with SIP showed smaller change in LL between standing-to-sitting positions (mean:6.3°; range:-8°-27°) compared with those without SIP (mean:9.5°; range:-12°-28°)(P = 0.006). No significant differences were noted in functional leg length between patients with (mean:7 mm; range:0-12 mm) and without SIP (mean:7 mm; range:0-11 mm)(P = 0.973).

CONCLUSIONS

This study revealed significant sacroiliac joint motion in patients with SIP post-THA, as indicated by PI changes, increased posterior pelvic tilt, and reduced change in the LL. Contrary to common belief, SIP did not correlate with LLD.

Non-invasive assessment of sacroiliac joint and lumbar spine positioning in different unilateral sitting postures

BACKGROUND

Sacroiliac joint (SIJ) motion has been documented using invasive and noninvasive kinematic techniques. No study has explored SIJ angular positions in functional postures using noninvasive techniques. The purpose of this study was to quantify SIJ positioning among different seated postures in a healthy population.

METHODS

Twelve female and 11 male healthy young participants participated. Left and right anterior and posterior superior iliac spines were manually digitized during standing, neutral sitting and four different seated postures. Rigid bodies recorded the kinematics of the lumbar spine. Angles calculated included transverse sacroiliac angle, innominate sagittal angle, sacral tilt, lumbar flexion-extension, lumbar lateral bend and lumbar axial twist.

FINDINGS

The observed range of angular positions was approximately 3 to 4 degrees across the SIJ-related angles. The main effect of seated posture was observed for all angles measured. The main effect of sex was observed for all angles except lumbar lateral bending. Females consistently experienced more posterior sacral tilt than males. Interaction effects between sex and posture were only observed at the right-transverse sacroiliac angle and sacral tilt. Previous sitting posture affected the subsequent neutral sitting posture for the right-transverse sacroiliac angle and lumbar spine angle.

INTERPRETATION

SIJ angular position differences among the seated postures were similar in magnitude to motions previously reported in participants undergoing prone passive hip abduction and external rotation. Sex differences, including greater sacral posterior tilt observed in females, likely reflect underlying morphological and physiological differences. Future studies should explore SIJ positioning during functional tasks in pathological populations to help elucidate the underlying causes of SIJ pain and inform treatment strategies.

Hip biomechanics in patients with low back pain, what do we know? A systematic review

BACKGROUND

Biomechanical alterations in patients with low back pain (LBP), as reduced range of motion or strength, do not appear to be exclusively related to the trunk. Thus, studies have investigated biomechanical changes in the hip, due to the proximity of this joint to the low back region. However, the relationship between hip biomechanical changes in patients with LBP is still controversial and needs to be summarized. Therefore, the aim of this study was to systematically review observational studies that used biomechanical assessments in patients with non-specific LBP.

METHODS

The search for observational studies that evaluated hip biomechanical variables (i.e., range of motion, kinematic, strength, and electromyography) in adults with non-specific acute, subacute, and chronic LBP was performed in the PubMed, Embase, Cinahl and Sportdiscus databases on February 22nd, 2024. Four blocks of descriptors were used: 1) type of study, 2) LBP, 3) hip and 4) biomechanical assessment. Two independent assessors selected eligible studies and extracted the following data: author, year of publication, country, study objective, participant characteristics, outcomes, and results. The methodological quality of the studies was assessed using the Epidemiological Appraisal Instrument and classified as low, moderate, and high. Due to the heterogeneity of the biomechanical assessment and, consequently, of the results among eligible studies, a descriptive analysis was performed.

RESULTS

The search strategy returned 338 articles of which 54 were included: nine articles evaluating range of motion, 16 evaluating kinematic, four strength, seven electromyography and 18 evaluating more than one outcome. The studies presented moderate and high methodological quality. Patients with LBP, regardless of symptoms, showed a significant reduction in hip range of motion, especially hip internal rotation, reduction in the time to perform functional activities such as sit-to-stance-to-sit, sit-to-stand or walking, greater activation of the hamstrings and gluteus maximus muscles and weakness of the hip abductor and extensor muscles during specific tests and functional activities compared to healthy individuals.

CONCLUSION

Patients with LBP present changes in range of motion, task execution, activation, and hip muscle strength when compared to healthy individuals. Therefore, clinicians must pay greater attention to the assessment and management of the hip during the treatment of these patients.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020213599).

First clinical results of a novel minimally-invasive fusion system for the sacroiliac joint

BACKGROUND

Sacroiliac joint (SIJ) painful dysfunction is a common source of low back pain (LBP). Several surgical treatment options for SIJ fusion were described. A promising treatment option with demonstrated clinical improvement is the minimally-invasive SIJ fusion.

OBJECTIVE

The aim of this case study was to document the effectiveness and safety of the new SIJ system (Torpedo®) over a period of 6 months after the minimally invasive implantation.

METHODS

Patients with failed conservative treatment of painful SIJ dysfunction were enrolled successively in two centers. The Diagnosis was made by positive response to SIJ-injection with local anesthetic and at least by two positive SIJ provocation tests. The Torpedo® Implant system was used for the implantation. This workpiece made of titanium alloy is characterized by a helical profile geometry (CST: chronical spinal turn) with a hydrophilic surface. The evaluated endpoints LBP and grade of disability were assessed using a 0-10 numerical rating scale (NRS), and Oswestry Disability Index (ODI) preoperatively and at one, three and six months postoperatively.

RESULTS

15 patients (10 female, 5 male; mean age 59 ± 13 years) were operated on one after the other. The pain intensity decreased in all 15 patients. After 6 months, a decrease in the median values of 70% (quartiles 1-3: 65-79%) was calculated. The median values of the Oswestry Disability Index after 6 months were 62% (quartiles 1-3: 53-67) lower than before the operation. Before surgery, 13 patients (87%) were taking opioids for pain management. Six months after the operation, opioids were only needed by 3 patients (20%). Implant malpositioning was not detected on plain radiograph. No surgical site infections or perioperative complications occurred.

CONCLUSIONS

The clinical improvement in early follow up and the absence of surgery related complications demonstrate a high grade of device-related safety and effectiveness of the treatment with a novel minimally-invasive SIJ fusion system.

[Minimally invasive arthrodesis of the sacroiliac joint (SIJ)]

OBJECTIVE

Pain reduction and improvement in quality of life with sacroiliac joint (SIJ) fusion.

INDICATIONS

Chronic SIJ-associated pain; positive response to SIJ injection with local anesthetic; positive SIJ provocation tests; failed conservative therapy over 6 months.

CONTRAINDICATIONS

Non-SIJ-associated pain; tumor/infection/unstable fracture in the implantation area; malformations; tumor or osteolysis of the sacrum or ilium bone; active infection at the implantation site; allergy to metal components; secondary gain from illness, request for a pension; inadequately treated osteoporosis.

SURGICAL TECHNIQUE

Transarticular placement of Kirschner's wires through the SI joint via minimally invasive lateral approach. Guided preparation of implant site over Kirschner's wires and implantation of 3 triangular, transarticular titanium implants for SIJ fusion.

POSTOPERATIVE MANAGEMENT

Deep vein thrombosis prophylaxis. 3 weeks partial weight-bearing and then moving on to full weight-bearing. X‑ray controls at defined intervals. Physiotherapy.

RESULTS

We enrolled 26 patients who were followed up over the period of 4 years. The evaluated endpoints were low back pain on the visual analog scale (VAS 0-10), grade of disability with the Oswestry Disability Index (ODI) and quality of life with the EuroQOL-5D. At 4 years, mean low back pain improved compared to preoperative (VAS preoperative 8.4, VAS 4 years postoperative 4.6). Mean improvements in ODI (ODI preoperative 58.1, ODI 4 years postoperative 32.1) and EQ-5D (preoperative 0.5, after 4 years 0.7) could be evaluated over the long-term period of 4 years. Satisfaction rates were high and the proportion of subjects taking opioids decreased at the 4‑year follow-up (preoperative 82%, postoperative 39%). Implant loosening could not be detected on plain radiograph.

Reliability and validity of manual palpation for the assessment of patients with low back pain: a systematic and critical review

BACKGROUND

Static or motion manual palpation of the low back is commonly used to assess pain location and reproduction in low back pain (LBP) patients. The purpose of this study is to review the reliability and validity of manual palpation used for the assessment of LBP in adults.

METHOD

We systematically searched five databases from 2000 to 2019. We critically appraised internal validity of studies using QAREL and QUADAS-2 instruments. We stratified results using best-evidence synthesis. Validity studies were classified according to Sackett and Haynes.

RESULTS

We identified 2023 eligible articles, of which 14 were low risk of bias. Evidence suggests that reliability of soft tissue structures palpation is inconsistent, and reliability of bony structures and joint mobility palpation is poor. We found preliminary evidence that gluteal muscle palpation for tenderness may be valid in differentiating LBP patients with and without radiculopathy.

CONCLUSION

Reliability of manual palpation tests in the assessment of LBP patients varies greatly. This is problematic because these tests are commonly used by manual therapists and clinicians. Little is known about the validity of these tests; therefore, their clinical utility is uncertain. High quality validity studies are needed to inform the clinical use of manual palpation tests.

Examination of the innominate movements in individuals with and without a positive march test

[Purpose] The March Test (MT), evaluating hypomobility of the sacroiliac joint (SIJ), is often used in clinical practice to evaluate low back pain but has limited reported validity and reliability. Capturing the innominate movement at SIJ associated with the results of MT has not been examined. The purpose of this study was to determine if there was a significant difference in the motion of the innominate between a positive and a negative MT. [Participants and Methods] Sixteen healthy volunteers were assigned into two groups: positive or negative results of the MT. All participants were asked to perform three different tasks: standing on both limbs, static standing on one-limb and flexing the hip to 90 and 100 degrees, and active flexing the hip past 90 degrees. In a 3D motion analysis system, virtual vectors created by landmarks over the ilium defined innominate movement of the ilium related to the sacrum, which were compared between the groups. [Results] There was significantly limited innominate movement in the March Test positive group compared to the March Test negative group. [Conclusion] This study showed hypomobility at SIJ in the March test positive groups. Further investigation is needed for clinical applications.

Comparative Analysis of the Pain Provocation Test and the HABER Test to Diagnose Nonspecific Low-Back Pain Associated with the Sacroiliac Joint

BACKGROUND This study aimed to investigate the correlation between the pain provocation test and the hip abduction-external rotation (HABER) test for diagnosing low-back pain (LBP)-related sacroiliac joint (SIJ) syndrome, and to determine the efficacy of the HABER test as a potential diagnostic tool for SIJ syndrome. MATERIAL AND METHODS One hundred patients with LBP participated. The first and second examiner examined the patients using the pain provocation test and the HABER test, respectively. Positive and negative findings were analyzed to determine the correlation and reliability. RESULTS The HABER test showed similar pain reproduction in groups that were positive or negative for SIJ syndrome (P<0.05). Based on the analysis of the receiver-operating characteristic curve, the cutoff values from the HABER test were found to be 29° and 32° of external rotation in the left and right hip joints, respectively. CONCLUSIONS The HABER test can reproduce similar level of pain in patients with chronic LBP associated with SIJ syndrome, and it can be used as a diagnostic tool in patients presenting with chronic LBP.

Association of thoraco-lumbar fascia length in individuals with non-specific low back pain - an observational study

OBJECTIVE

The purpose of the study was to assess the length of TLF and to evaluate the strength of muscles attached to it in subjects with and without nonspecific low back pain (NSLBP).

METHODS

31 patients with NSLBP and 31 healthy individuals were included in the study. In each subject the TLF length was assessed by quantifying lumbar rotation using Back range of motion (BROM-II) instrument. The endurance of transverses abdominis was assessed using the pressure biofeedback unit while the strength of Latissimus dorsi, internal and external oblique's were assessed using MMT. Outcome measure such as Range of Motion (ROM) was compared across the group using independent sample T-test. While the muscle strength of Latissimus dorsi and oblique's were compared across the group using Man-whitney U- test. Transverse abdominis endurance was tested using chi-square test.

RESULTS

There was statistically significant difference in the length of TLF of subjects with NSLBP when compared with subjects without NSLBP. When the strength of Latissimus dorsi muscle, transverses abdominis muscle and internal and external oblique's muscle was assessed no significant (p value > 0.05) difference was found in either group.

CONCLUSIONS

There was statistically significant reduction in length of TLF but there was no difference in the strength of Latissimus dorsi, internal and external oblique's or endurance of transverses abdominus attached to the TLF in individuals with NSLBP and without low back pain. This study will help in determining the inclusion of TLF and the associated structures in evaluation and management of subjects with NSLBP.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of low back pain

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016.

PURPOSE

The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

This is a guideline summary review.

METHODS

This guideline is the product of the Low Back Pain Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors.

RESULTS

Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature.

CONCLUSIONS

The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx.

The association between sacral morphology and sacroiliac joint conformity demonstrated on CT-based bone models

INTRODUCTION

Knowledge of the stress distribution on structures around the sacroiliac joint (SIJ) is required to treat or prevent SIJ disorders. The purpose of this study was to reveal the association between sacral morphology and SIJ conformity.

MATERIALS AND METHODS

This cross-sectional study included 11 adult patients with unilateral SIJ pain who underwent computed tomography (CT) imaging of the pelvis. Bony coordinate systems for the sacrum and innominates were embedded using anatomical landmarks. Local coordinate systems for the auricular surfaces of the sacrum and innominate were also defined. Conformity of the SIJ was quantified by the offset of the coordinate systems between the auricular surfaces of the sacrum and innominate. Repeated measure ANOVA and multiple regression analysis were used for statistical analyses.

RESULTS

There were large variations across subjects in sacral morphology and SIJ conformity. There were no differences in any of the six degrees-of-freedom positions or orientations of the bilateral sacral and innominate auricular surfaces between the symptomatic and asymptomatic sides. The SIJ downward rotation on the asymptomatic and symptomatic sides were 0.0 [-1.0, 1.1]° and 2.1 [1.2, 3.0]°, respectively. Smaller downward rotation of the sacral auricular surface based on the sacral bony coordinate system had significant association with the greater SIJ downward rotation (standard partial regression coefficient: -.44, p = .043).

CONCLUSIONS

The results indicate that the morphology of the sacrum is associated with poor SIJ conformity and that separation of the superior portion of the SIJ can be a risk factor for SIJ pain.

What do we know about the biomechanics of the sacroiliac joint and of sacropelvic fixation? A literature review

The purpose of this review is to summarize the general knowledge about the biomechanics of the sacroiliac joint and sacropelvic fixation techniques. Additionally, this study aims to support biomechanical investigations in defining experimental protocols as well as numerical modeling of the sacropelvic structures. The sacroiliac joint is characterized by a large variability of shape and ranges of motion among individuals. Although the ligament network and the anatomical features strongly limit the joint movements, sacroiliac displacements and rotations are not negligible. Currently available treatments for sacroiliac joint dysfunction include physical therapy, steroid injections, Radio-frequency ablation of specific neural structures, and open or minimally invasive SIJ fusion. In long posterior construct, the most common solutions are the iliac screws and the S2 alar - iliac screws, whereas for the joint fixation alone, mini - invasive alternative system can be used. Several studies reported the clinical outcomes of the different techniques and investigated the biomechanical stability of the relative construct, but the effect of sacropelvic fixation techniques on the joint flexibility and on the stress generated into the bone is still unknown. In our opinion, more biomechanical analyses on the behavior of the sacroiliac joint may be performed in order to better predict the risk of failure or instability of the joint.

The effectiveness of traditional Thai massage versus massage with herbal compress among elderly patients with low back pain: A randomised controlled trial

OBJECTIVES

To determine the effectiveness of including an herbal compress in a traditional Thai massage regimen for the care of low back pain in the elderly.

DESIGN AND METHODS

This study was a randomised controlled trial. The sample consisted of 140 patients suffering from non-specific chronic low back pain, who were randomly assigned to either the TTM (n = 70) or TMH (n = 70) group. The primary outcome was pain intensity (Visual Analogue Scale), and the secondary outcomes were disability, back performance and quality of life. The outcome measurements were assessed at baseline, 6 weeks and 15 weeks.

RESULTS

There were no statistically significant differences in the primary and secondary outcomes between the two study groups (p-value > 0.05). Although improvement was observed for both groups in pain intensity, disability, quality of life, and back performance.

CONCLUSIONS

There was no additional benefit of including an herbal compress in a regimen of Thai massage for the care of low back pain in the elderly.

Pelvic Incidence Changes Between Flexion and Extension

STUDY DESIGN

Retrospective single-center.

OBJECTIVES

To investigate changes in pelvic incidence from flexion to extension. To assess interobserver error in the measurement of pelvic incidence.

BACKGROUND

Pelvic incidence (PI) has been considered a static parameter since it was originally described. But recent studies have shown that PI can change with age and after spinal procedures. Changes in PI based on position have not been investigated.

METHODS

Seventy-two patients who had obtained flexion and extension radiographs of the lumbar spine were identified using strict inclusion and exclusion criteria. PI along with pelvic tilt (PT), sacral slope (SS), and lumbar lordosis were measured in both flexion and extension by two independent measurers. Variations in all parameters and interobserver measurement reliability were analyzed for the entire group.

RESULTS

PI changed significantly from flexion to extension with a general tendency to decrease: mean (-0.94°), p <.044. However, these changes might have had opposite vectors, and exceeded | 6°| (measurement error) in 20% of cases, with a maximum of 12°. Inconsistencies in changes of SS, as opposed to PT from flexion to extension, were found to be the major factor determining changes in PI (p >.001). Obesity significantly contributed to differences in PI between flexion and extension (p = .003).

CONCLUSIONS

PI is a dynamic parameter that changes between flexion and extension. Changes in SS are the main factor involved in these changes, implicating movement through the sacroiliac joints as the cause. Obese patients have greater changes in PI from flexion to extension.

LEVEL OF EVIDENCE

Level II.

Pelvic orthosis effects on posterior pelvis kinematics An in-vitro biomechanical study

The sacroiliac joint (SIJ) is a well-known source of low back pain, with increasing interest for both conservative and surgical treatment. Alterations in pelvis kinematics are hypothesized as a contributor to SIJ pain and pelvic orthoses one treatment option, but their effects on the pelvis are poorly understood. Alterations in movement patterns induced by the application of pelvic orthoses were determined in five human cadaveric pelvises. Deformations were obtained from the lumbosacral transition and the bilateral SIJ, using digital image correlation and a customized routine to compute the movements within the pelvis. Significant alterations were found for the movements at the SIJ, in particular a vast increase in axial (x-axis) rotation, accompanied by increased inferior (y-) translation of the sacrum relative to the ilium. Movement patterns at the lumbosacral transition changed, causing increases in axial rotation and decreased inferior translation of L5 relative to S1. Using a physiologic mode of load application gives novel insights into the potential effects of pelvic orthoses. The results of these in-vitro experiments vary markedly from previous experiments with loading limited to two or less axes. Furthermore, the influence of pelvic orthoses on the lumbosacral transition warrants further investigation.

Innominate segment deformation during passive hip abduction and external rotation

BACKGROUND

Electromagnetic palpation-digitization technique for measurement of innominate motion involves calculation of innominate rotation using the innominate vector length in the neutral (NEUT) and combined hip abduction and external rotation (HABER) test positions. The innominate vector length [i.e., the segment between anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS)] is not a rigid structure and its deformation could introduce an error influencing the final innominate rotation measurement.

OBJECTIVES

The aim of this study is to determine if there is significant deformation occurring in innominate vector length when the hip is loaded into the HABER test position.

METHOD

A cross sectional study using sixteen healthy individuals and a single tester was conducted. Four pelvic landmarks, left and right PSIS and ASIS, were palpated and digitized using 3D digitizing stylus of Polhemus electromagnetic tracking device, in two hip test positions, NEUT and 50° HABER. The innominate vector lengths were calculated from the 3D coordinates of pelvic landmarks, for each hip test positions.

RESULTS AND CONCLUSION

Paired t-tests demonstrated no significant differences (p > 0.05) in the innominate vector lengths at the side of the load as well as the opposite innominate when either the right or left hip was loaded; thus indicating no significant bone deformation in innominate segment during the HABER test position.

Does repeated palpation-digitization of pelvic landmarks for measurement of innominate motion introduce a systematic error?--A psychometric investigation

BACKGROUND

Palpation-digitization technique for measurement of innominate motion involves repeated manual palpation-digitization of pelvic landmarks, which could introduce a systematic variation between subsequent trials and thereby influence final innominate angular measurement.

OBJECTIVES

The aim of this study is to quantify the effect of repeated palpation-digitization errors on overall variability of innominate vector length measurements; and to determine if there is a systematic variation between subsequent repeated trials.

METHOD

A single group repeated measures study, using four testers and fourteen healthy participants, was conducted. Four pelvic landmarks, left and right posterior superior iliac spine and anterior superior iliac spine, were palpated and digitized using 3D digitizing stylus of Polhemus electromagnetic tracking device, for ten consecutive trials by each tester in their random order. The ten individual trials of innominate vector lengths measured by each tester for each participant were used for the analysis.

RESULTS AND CONCLUSIONS

Repeated measures ANOVA demonstrated a very small effect of repeated trial factor (≤0.66%) as well as error component (≤0.32%) on innominate vector length variability. Further, residual versus order plots demonstrated a random pattern of errors across zero; thus indicating no systematic variation between subsequent trials of innominate vector length measurements.

Can hip abduction and external rotation discriminate sacroiliac joint pain?

AIM

The primary aim of the study is to determine if Hip Abduction and External Rotation (HABER) test is capable of reproducing familiar pain in individuals with low back pain (LBP) of sacroiliac joint (SIJ) origin (SIJ-positive) when compared with LBP of Non-SIJ origin (SIJ-negative). If so, the secondary aim is to determine the diagnostic accuracy of HABER test against the reference standard of pain provocation tests, and to determine which increments of the HABER test has highest sensitivity and specificity for identifying SIJ-positive individuals.

DESIGN

Single-blinded diagnostic accuracy study.

METHOD

Participants [n(122)] between ages of 18-50 y, suffering from chronic non-specific LBP (≥3 months) volunteered in the study. An experienced musculoskeletal physiotherapist evaluated and classified participants into either SIJ-positive [n(45)] or SIJ-negative [n(77)], based on reference standard of pain provocation tests [≥3 positive tests = SIJ-positive]. Another musculoskeletal physiotherapist, blinded to clinical groups, evaluated participants for reproduction of familiar pain during each increment (10°, 20°, 30°, 40°, and 50°) of HABER test.

RESULTS

The HABER test reproduced familiar pain in SIJ-positive individuals when compared with SIJ-negative individuals [p (0.001), R(2) (0.38), Exp(β) (5.95-10.32)], and demonstrated moderate level of sensitivity (67%-78%) and specificity (71%-72%) for identifying SIJ-positive individuals. Receiver operator curve analysis demonstrated that the HABER increments of ≥30° have the highest sensitivity (83%-100%) and specificity (52%-64%).

CONCLUSIONS

The HABER test is capable of reproducing familiar pain in SIJ-positive LBP individuals and has moderate levels of sensitivity and specificity for identifying SIJ-positive LBP individuals.